Morning everybody. My name is Davide. I'm a production engineer at Facebook, and this talk is about the work we do with Stream. Here's the agenda for today. We'll start with a quick introduction about our infrastructure. We'll dive into what we do specifically with Sendos and how we use it. We'll talk about how we contribute to upstream and how you can contribute to upstream leveraging Sendos Stream as well. And finally, we close with some words around deployment and management. So let's go over infrastructure. Facebook has a lot of machines. We have millions of servers across the globe in multiple data centers. All of these machines are physical machines. All of these machines run Sentos. And that has been through for many years, as far as I know, since the company was started. And the common theme throughout this is that we try to manage this fleet in a crazy way, and we try to leverage open source software as much as we can. I work on the operating systems team. He manages the bare metal experience of the fleet. We treat the operating system as a platform in the sense that we try to build a common layer that other teams that the company can leverage directly. Teams that run directly on bare metal will interface directly with the US. Teams that run on the container platform will interface with the container platform, which itself runs on top of Sentos. And the containers, by the way, also run Sentos. Teams at Facebook are expected to be responsible for their own machines and their own services. So our team often acts as kind of a consulting partner where we will build tooling and try to set up systems in a way that can be useful and solve problems. And then it's up to the individual owners of, say, MySQL or the web servers or whatever to make sure that their services work properly, they're monitored and so on. A constant theme throughout this is that we try to build our infrastructure on top of an open source foundation. There is no point in reinventing the wheel. And we very much want to try and leverage the work that the community has done and contribute to the community as well as much as we can. So we use Linux, obviously, we use Sentos. We use the standard packaging stack a lot. We use Chef for config management and we use system D throughout the infrastructure. And I'll talk about all of these components more closely in a little bit. But first I want to say a few words about why we actually do this. I had these lies in my talks for quite a while now, but I think it's important to go over these in general. We try as much as possible to work with open source because we think the community is where the innovation tends to happen and the community is what ends up setting the direction. If we can work with the community on features, try to make our use case understood, try to better understand what the community wants. We can make things better for Facebook, but we can also make things better for the world at large. And while Facebook prises itself on moving fast, the reality is that community often moves even faster. It is quite common for us to find out that we have a problem. We start analyzing it and trying to figure out what we should do, and then we find out that it's already been solved by the community at large and we can either import the solution as is or we can make minor changes, contribute back and solve the problem for everybody. We don't need to write anything ourselves. And at the same time, the fact that we can leverage the community's work means also that we can share our work. We can share our work, we can share our code, we can share the maintenance in, we can have other people contribute to it. And from an engineering standpoint, at least for me, it is much more pleasant to know that I am working on something that other folks can actually leverage and use and maybe make the life a little bit better. There's a token I gave in a DEF CON theme in 2017, that was a while ago. It's still fairly relevant though, so if you're interested more into our approach here, you are going to watch it. I left talks referenced throughout this presentation because this is only a 40 minutes long, so I'll try to not go into much details in things that have already been covered in the past. Now let's talk about centers. But first, before we talk about centers, let's talk about why we actually run centers. As I said, we've been running centers for quite a while. We've been at Facebook since 2012, and at the time we were running Cent5, and now we're running CentOS 3Mate. There's been some constant themes throughout this. CentOS gives us a lot of things that we like, and it also gives us the ability to fix the things we don't necessarily like or that don't necessarily apply to our environment. Well, first thing first, CentOS gives us stable releases. It gives us a stable base that we can build upon, that is known to work, that is known to be well tested and gated. Note that this is true both for CentOS Linux and for CentOS 3M, because they have effectively the same gating. So from that point of view, nothing has actually changed. CentOS also gives us binary compatibility. Binary compatibility is very important because binary compatibility means that if you go on a live system and you run DNF upgrade, you can be certain to a very high degree that the services you are currently running on the machine will keep running on the machine, that you won't need to reboot, that you won't need to kill random things for stuff to keep working because GNPC suddenly changed the way it works. This is what makes it possible for us to do minor updates on the fleet live throughout the lifecycle of the system by just sharpening them out. CentOS also obviously gives us security updates, which is something else that is clearly very important, but it's also something that ties in with the binary compatibility because without that we would not be able to live this live in a safe way. CentOS gives us good tooling and tooling that is very well understood. Things like the packaging stack at this point are very mature. There are tools that have been around for a long time. There are tools that people know how to work with, know how to contribute with and make changes if needed. And finally, CentOS is part of a larger ecosystem. CentOS itself is a fairly conservative distribution, that it doesn't carry that many packages, and the same is for REL because it's effectively the same kind of packages, but it doesn't carry that much beyond core system packages. But because CentOS is part of the Fedora ecosystem, we also have access to everything that is packaged in a PEL, and we also have access to everything that is packaged in Fedora. And if something is missing from a PEL or Fedora, we can work with those communities to make it available. And that is something that has been extremely valuable throughout the years. So the approach we've generally taken at Facebook is that we run a CentOS base, and then we backport on top of it what we end up needing from Fedora or Hype. So these are generally things that are system-bombing. Either packages that we work on very closely with upstream, so we want to know that we are running the latest master or the latest stable release so that if we make any changes we can contribute them back without having to worry about backporting. Or if we use system and low-level packages that we work on. We try to publish our backports on GitHub and I'll talk more about this later and how we're trying to make this easier to consume. The way this time to be written is that we have a macro to get Facebook-specific stuff and configuration, so the packages themselves can also be useful to people that are not Facebook. We found throughout the years that the approach of combining CentOS with this, what we call this fasting layer, this layer of packages that we backport, this is a stable distribution that can move as fast as we need and at the pace we need in the various components. The other thing we do that deviates from CentOS proper is that we don't run the CentOS kernel. The CentOS kernel is a very stable kernel, but it tends to be based on a fairly old kernel version compared to what is currently in Linux 3. If those are kernel that tends to have a lot of backports, because our kernel team does a lot of development on many features and subsystems, and they do all of this development in master, it's a lot easier for us to just run effectively Linux history or something close to Linux history rather than doing work to then backport these to an older kernel. And we do a lot of kernel work. We do a lot of kernel work both on specific features and subsystems and general fixes. Although this is work that doesn't really happen internally at Facebook, it's all work that happens outside in the open. And while there is an internal development branch of the kernel, it's effectively used mostly for staging patches and make it easier to roll changes. The way it works in practice is that we tend to have two kernels concurrently in the fleet, one that's stable and one that is development, and then we slowly update them and move them on, but they tend to be very close to mainline. Some examples of features that we worked on throughout the years that we continue to work on are the ButterFS file system. The resource control features leverage in SIGIRV2. There's been a lot of work on resource control lately, and resource control also ties with ButterFS because ButterFS is what actually makes it possible to have reliable IO control. Within resource control, there's also been a lot of work later on PSI, which is a feature in the kernel that effectively allows you to predict the future and tell whether a process is likely to oom in the near term, so you can do something about it before the kernel invokes the oom killer and kills it. And finally, we do a lot of work on BPF and the BPF toolset. This is just a short rundown. There's a lot more stuff happening in the kernel. We have tooling that we use to roll out kernels and test them and make sure this is done safely. These days, it's actually the same tooling we use for the operating system, and I'll talk about this later. There's an old blog post I linked there if you're interested in learning more about the kernel. And other components that I mentioned before that we work on is SystemD. As I said, we do a lot of work on SystemD and with SystemD. So we try to follow the SystemD upstream, and we maintain a SystemD back port that's available in the 3-byte mansion. The way we do work with SystemD is that we'll take the data stable release, we'll add whatever patches we have in development that either have been already submitted upstream and accepted, or that are currently in review. And then we feed it to our CI-CD pipeline, which will run it through a battery of tests. It will also run it against tests against our container suite. It tends to stress things quite a bit. And then if we find any issues, we report them back upstream or fix them directly. And then we just roll it out. We've started using SystemD at Facebook when we were doing the Sense7 migration, and this went from a handful of people that were doing work with this and the rest of the company being fairly skeptical to almost everybody effectively embracing SystemD and wanting to leverage its features and work with it. And we've done a lot of feature development as well throughout the years. I'm not going to talk about these in-depth, because I've given a lot of talks about this before, and I'll link one below there. One thing I do want to highlight though is SystemD UMDI, because it's a fairly recent change, and it's also something that's coming in Fedora for 34. SystemD UMDI is a new kind of user space.  So the way SystemD UMDI works is that it figures out why your system is running, if there's a process that's about to spill over and you invoke the human killer, and it deals with it before that actually happens. So it can act in a much more precise way and it avoids bringing down your whole system. This is something we are running in production at Facebook now, and it's something that is already merged in SystemD upstream for two for six, I believe, two for five. Yeah, we also have a few other projects that are tangential to SystemD. Back in Descent, when we started doing SystemD, we've got some Kampa libraries to make it possible to run a modern SystemD, when we're doing System7, sorry. We've got Kampa libraries to make it possible to run a modern SystemD on the distribution, because the distribution was still using an older version. This is not terribly relevant these days, and it's something with probably Sunset with Nine. We also have a project called PythonD that gives you a nice Python abstraction on top of SystemD, and because you use this Python, it links directly to SystemD, and it's very fast and very useful, especially if you're into do operations over a debus. This is also packaged in both Skid or NFL, if you want to use it. Finally, a few words about packaging. As I said, we use a standard packaging stack. We use RPM and DNF and YAM. Because we've been doing this for a while, we found pretty much anything that can go wrong in the packaging stack at this point, and I dealt with it at some point. In general, when you're operating a fleet as large as Facebook, anything that can go wrong will go wrong, and it will go wrong a lot. Even issues that normally would manifest themselves on 0.1% of your machine or in your situation, they end up becoming a lot of machines that you have to deal with. With the RPMDB specifically, this was evident when we were still using Berkeley DB, because Berkeley DB was fairly brittle and fairly easy to mess up, and we've wrote a tool set called DCRPM to deal with the situation to identify the state of the RPMDB and re-mediate corruption and do a bunch of housekeeping around it to try and make things better. This is also open source, and it's also packaged in Fedora, which is one of the main issues today. The other thing we did was work with the community. The community was already aware of this problem and had developed some alternative RPM databases to test. At the time, there was LMDB and NDB, so we took those two, we AD tested them by effectively putting them on a lot of machines and comparing results, and we ended up switching to NDB from Berkeley DB, and this all but eliminated RPMDB corruption as far as we can tell, so this day on the fleet at Facebook, everywhere. There's also some work in progress happening in the space. The main thing I want to mention is my colleague Matthew Almo's work on Levered, Geodef, and RPM Copy on Brite. The idea here is to use the features that are provided by modern file systems like ButterFS to make packaging stores much faster, much faster and much less expensive. Matthew gave a talk at Dojo 2021, not 2020, two weeks ago, and I linked it there and it goes indeed along how this works. This has also been proposed as a change proposal for 34, although we will punt it to 35 because there's more work needed there. But this is something we're very excited about and it's something we are currently also running in production and has provided a lot of performance improvements. Finally, I mentioned the RPMDB before. The community already moved on and now it's using SQL Live, especially in Fedora for the RPMDB. So we plan to start evaluating that shortly and assuming it works just as well as NDB, which I expect will switch over there so we can stay closer and not keep a delta if we can avoid it. Okay, there's a few more things that we do that tend to not be what you would normally expect if you run bare Sentos. And these are all things we do to either better fit in our environment or better fit with our workload. So for example, if you install Sent 8 today, it comes with SIGURP 1 by default and it will install on XFS. Because we do a lot of work on resource control and when I leverage these features, by default we will set up machines with SIGURP 2 and we will use better FS from the root file system. SIGURP 2 and better FS combined is important because it's what keeps you working IO control. And that is something we use a lot at Facebook all over the place. We started making better FS the default with Sentos 8 when we started switching over and it has been our resounding success so far. We were using better FS long before that, of course, but it wasn't the default for the root file system. We also had a few other minor changes in the infrastructure. In Sent 8 specifically, IP table ships without the NF table, without the legacy backend, only with NF tables. But our kernel folks don't really want to support NF tables for a bunch of reasons, so we rebuilt it with the legacy backend enabled. On the networking front, historically, we've always used network scripts instead of network manager. Network scripts package as part of image scripts if you're not familiar. It's what used to be the default that we used earlier, I believe. So that's what we still use. This is likely something we'll re-evaluate when we start working on 9. What I suspect we'll end up doing is using system-de-network B, but we haven't actually done any evaluation on this yet, so we'll see. Again, there's a link to another talk if you want more details about these specific things and why we would make the choices we make. Okay, I went fairly fast on that. And I went fairly fast on that on purpose because the part I want to focus is actually the part about upstream and upstream contributions, because I think that's the interesting and the important bit at this point, the bit that, when people have talked about it, I don't think it's necessarily well understood in general. So to talk about this, let's take a step back and think about how the distribution is built. And of course, there's diagrams, which hopefully will make sense. So I'll go over examples of how the distribution is built in Windows 7. So the way CentOS and to be clear, I don't work at Red Hat, I've never worked at Red Hat. This is based on public information and my understanding of things. So if something is blatantly wrong, please mention it in the chat and we can talk about it later. So the way CentOS 7 was built is that Red Hat takes Fedora 19, they took Fedora 19 when it was released and they took a snapshot of it. They revealed the whole distribution with a bunch of special macros so that it comes out as EL instead of Fedora. And then they start actually testing the distribution and working on it. All of this happens inside Red Hat in effectively a staging distribution that is in public that ensures a name for the people that work on it. When the staging distribution evolves from like a primordial soup to an actual distribution that people can use, this becomes something that has testing and gating applied. So when updates are added to it, the updates go through a testing and qualification phase before they then make it out. Then this distribution is what gets shipped as Red Hat 7. When a Red Hat 7.0 comes out, CentOS Linux 7.0 is built and CentOS Linux 7.0 is built by taking the sources of Red Hat 7 that come out publicly and rebuilding them. It has no input whatsoever from what happened on the stage previous. And then throughout the lifetime of 7, this goes on. So 7.1 also comes out of the staging distribution, which at that point is effectively the same as Red Hat and it's a stable distribution that gets updates. These updates are gated and tested and then once a bunch of these have been modeled up, it's released together as Red Hat 7.1 and then CentOS Linux 7.1 and so on. I forgot how many point releases 7 ads, so I'll just put the ads there. Now, if you look at this from a birth idea, let's say you want to contribute your CentOS user and you want to contribute to CentOS Linux because, say, you found a bug in 7.0 in CentOS Linux. What can you do? Well, let's see. You could contribute to CentOS Linux directly, but not really because CentOS Linux is just a rebuild of RHEL. So there is no, apart from logic to do the actual build and some binding changes, there isn't anything in CentOS Linux that isn't in RHEL, so you can't really change anything in CentOS Linux because by definition this doesn't have any deviations from RHEL. So, okay, I guess you could contribute to RHEL, but not really because RHEL is a commercial product. You can certainly file bug reports on RHEL and if you file bug reports and attach patches, those might end up to the right person and they might eventually make it to a stable point release on the road. We actually tried doing this back in the day at Facebook. It took us many months to get a one-line fix merged and this was via pinging people we knew when asking for favors and stuff like that. This is clearly not a viable option and even if you were on RHEL as a commercial customer and as a support contractor and everything, that's mostly geared towards support, not towards contributing changes and trying to do that. So, you're kind of stuck because obviously you can't contribute to the staging because that's internal. The only component you can contribute to in this world is effectively only Fedora. And while you can certainly contribute to Fedora, that's not really going to help you if you're running CentOS Linux 7 now. That may help you if you plan to move to CentOS Linux 8 or 9 down the road because changes in Fedora eventually trickle down to new major releases so you end up doing what we ended up doing and a lot of people do, which is where you end up maintaining a lot of logic internally and backwards and then you try to talk to people and get things fixed via batch channels. This wasn't an ideal situation and this is something everybody was well aware of and this is where stream came in. So let's look at what the picture is with 8. It is actually very similar. There's two changes you can see here. Well, it's Fedora 28 because the world moved on. But also effectively the staging distribution isn't there anymore and instead of that we have CentOS 3Mate. And CentOS 3Mate is public now. It is an actual distribution that you can run, it's an actual distribution you can contribute to. And this is a major change because now, well, you still cannot contribute directly to CentOS Linux because obviously it's already built up already, you can contribute to stream. You can try to get stuff fixed there and it will make it into stream assuming it passes the testing and negating and the maintainers of course thinks the change is not insane. And then from there it will eventually make it to REL and CentOS. So this is a major change because now you suddenly can actually contribute to the distribution and I want to stress this doesn't mean the CentOS 3Mate is all high for CentOS because it's effectively the same as before with the staging distribution. This is effectively REL except it's not REL 8.0, 8.1, 8. whatever. It is REL with all the updates up to this point where when new code is added or when new packages are added are packages that have gone through all the gating and testing that they would have gone if they were shipped to customers in REL. So it's effectively something that is as stable as REL. Now the other difference in this obviously unless you've been living under a rock is that CentOS Linux 8 has been effectively sunset. So at one point there will be REL 8.1 that won't have a corresponding CentOS Linux but CentOS 3M will always be around. Now this is a much better situation because now you can contribute to Fedora if you want to make changes to the new version of REL and CentOS but you can also contribute to CentOS 3Mate now if you want to fix things right now in it and eventually affect the next REL minor release. However there's still a bit of a mismatch here because how do we go from Fedora to CentOS 3M? Effectively for us and for everybody else when CentOS 3Mate came out it was oh here's a drop that's great but how do you make this where it's come from? And that's what I think would get interesting when we have 9. So when we have 9 there's another box in there which is ELN and effectively that's another piece of what used to be internal red-up process that now becomes available to the world. I mentioned before that the first thing folks would do when they start building a new version of REL is that they'll take Fedora and rebuild it with a bunch of different macros and settings to make it an EL distribution. That's the fact that what ELN is doing except it's not doing it on internal REL infra but it's doing it in the open within Fedora right now and Fedora ELN is a Fedora project. So that also moved a large chunk of this process and tooling out in the open as something you can actually contribute to and inspect and work on. And while the 9 cycle as well ELN has started already but the actual 9 cycle is the public one hasn't started yet my expectation is that this will make 9 a much better product and a much easier product to work on and to contribute to as well. With 9, Centus Linux isn't in the picture anymore because it won't exist anymore as a rebuild of REL at least as a Centus product there's going to be there's most likely going to be plenty of non-reddit and non-Centus product that will do that but Centus Trim will be around and it will give you the same guarantees of stability that REL gives you as a distribution you can actually contribute to. I think the block was there from a former colleague of mine to live with who went over these extensive BNFs a lot of diagrams that explain in more detail how this works and also as references to other talks you may want to watch to understand it and I know that every talk that references Centus Trim in the last few months had this kind of diagrams and stuff and I hope this help a little bit making things clear for people that weren't sure how this worked so what can you do so you can contribute to Fedora Fedora effectively influences what we're going to the next major release how can you contribute to Fedora join the Fedora project and do work there file bugs maintain packages, work with maintainers drive changes Fedora has a wealth of opportunities for people to contribute both in Fedora proper and in appell and it's an extremely welcoming community that would encourage everybody to work with if you want to assist in the bring up of stream you can work with the LN I don't actually know very much about the LN besides what came out in the million least and what people have talked to at conferences well today for me because it's going to be at midnight here I highly recommend you join the meetup if you're interested because I expect that will be a very useful place to have this kind of conversations and finally you can also contribute to stream stream is now a continuously delivered version of Rattle effectively it's a continuously delivered distribution that tracks the next minor of Rattle and it is something you can contribute to you can file and fix bugs you can send cool request on packages you can fix things and you can join a SIG or make a SIG SIGs are the building blocks of the Santos community and where all the actual major work happens so let's talk about what we are doing in Fedora as an example we've been involved with Fedora on and off for a while I say we started getting actually involved with Fedora about a year ago engineers from Facebook actually started to read the mailing list to be involved with the project to actual work there not just file bugs and stuff so myself and a bunch of other engineers did work to try and get some of our tooling and software packages with Fedora among other things we got most of our application stack package there not necessarily because we're using it at Facebook because the way we build our internal software at Facebook is very different but because we think it is useful to have it out there so that people know it exists also we think it's useful to have it out there because Fedora runs on a variety of other architectures for example we can leverage the fact that it does CI for these architectures and things like that and we can get feedback on that and at the same time I don't know if you've ever tried building a project that comes out of Facebook or Google or one of these large companies unless you work there it is not particularly fun so my hope is that by these things being actually packaged people can use them and maybe provide feedback more directly we also package tooling that we use in the infrastructure that before we were maintaining internally things like DCRPM that I mentioned before there's really no reason why we wouldn't package those in the distr we've done feature enablement work and we started getting involved with RASIG we also had several change proposals out starting from 1333 we worked with the community to switch Fedora to use a battery fast by default with 34 we are working to have standard compression by default and we are also working to switch from early on to system D I mentioned the DNF copy and write work a moment ago that is also something we are working on in the 34 time frame although that's called the third to 35 because there are more work and finally we are doing work with the RASIGs to make it easier to get packages branched and updated for Apple when needed you can find out into a talk that my colleague Michelle gave a thought to them Michelle works on the desktop team and he's been helping us a lot working with Fedora on the center side we started the SIG we started a SIG called hyperscale in collaboration with other companies and the goal for the SIG is to make it easier for large companies like facebook and twitter but really for anybody else who wants the development work in stream to have a place where they can build packages packages that may be updates of base for example and get them deployed on the infrastructure and leverage the upstream tooling here and contribute as much as possible I'm going to be faster because I realize I'm running out of time we are focusing these on a few things we're focusing these on package backwards so effectively the stuff I mentioned before that we currently have in our own repository on github we would like to move within the SIG because we think it would be a lot easier for people to contribute to and we also think it would make it easier to move changes between Fedora and send us proper so these are all things that we are working on right now at various stages system D something that we will probably publish next week currently something that started working yesterday of course it's a small package we use to actually test this process we have a lot of different members of the SIG working on things like Libre, RESTemon and a bunch of other packages we also use this as a space to publish deviations of base packages with different config settings so I mentioned that we build IP tables for example with the legacy backend still enabled there's not really any reason for not publishing that so we will have that available in the SIG as well and finally for things like the rpm copy on write work that I mentioned that working both rebuilding the entire packaging stack to actually test it why is this something you could theoretically put in a copper we believe there is use for having a version that is tested and actually deployed in production available somewhere for people to test so it can be tested and used before it actually gets published out at Meridian Fedora there's also some discussions about building an alt kernel for sentos to a better feature enablements for things like battery efficiency but this is still in very early stages and at the discussion stage so I don't have anything to show for this yet right now however if you go and get to sendos.org you can find branches for the SIG on a few packages like systemd and there is already a package repository you can enable if you do dnf install sendos release hyper scale and this would give you access to I think right now there's only dwarfs in there so it's not terribly useful but starting from next week I will make sure to post on sendos develop when that happens so people know it's there in the near future we'll have another repository for experimental and then as I mentioned the external work being discussed and we hope to at some point also publish cloud images I want to say a few words about deployment before I run out of time I mentioned we use Chef we've talked about Chef a lot before Chef does config management if you're familiar with Ansible or Puppet it's a package with the same category of product I'm going to skip this because I think mostly everybody knows how this works at this point there are links here to the things that you can use if you're interested in using Chef in your infrastructure with the same model that Facebook uses and with the same tooling and some of this is also packaged in Fedora what I think people are more interested in hearing about is how we do updates because that is something that has come out a lot so we split between minor and major updates for minor updates what we do is that we snapshot the repo beat the repo that used to come from Centus Linux 7 or 8, Centus of 7, 6 or 7 are the repo that comes out of Centus Trim and we snapshot it every couple of weeks and then once we have this snapshot in the repo we roll it out the fleet over the course of two weeks and the way we roll it out is that from Chef we basically just run DNF upgrade with some logic around the 10 queries of course because sometimes you have to do special things especially if you have internal packages that are rebuilt and shadowing so we've done this process in Centus 6 as far as I remember at this point it works very very well and it allows us to do this live on live machines running real traffic and real work without any actual impact all thanks to the binary compatibility that's guaranteed by Centus now this is for minor updates for major updates we just rate provision we've decided long ago that it's not worth the trouble to try and do major updates in place even if it's technically possible we also like the fact that we get a clean slate and that this gives us a watershed event that we can use to also make policy changes if we want to so for example when we do 7 to 8 we enable battery fast by default that requires wiping the drives well yes effectively yes you can do conversion in place but we're not going to do that so things like that are very useful because if you're going to have to rate any way to update you might as well do these things and we have tooling that is generally available to do this leverage maintenance windows so we can do things like the tooling knows how many machines it can take out at the same time without impacting user services and do this in a safe way as I said we've done this a bunch we did 5 to 6 6 to 7 we are at the tail end of 7 to 8 right now and we're going to be doing 9 lightly at the end of this year or next year again link to a talk where I talked about how the updates work specifically right now 85% and 5 and change as of this morning is on stream 8 we do have a long tail of 7 because you always have a long tail when you join these things the long tail right now is things like switches which because as I said we reimage and reboot everything connected to the switch goes down so switches take a while to update because they require extra coordination because they effectively get offline the entire rack and yes the switch is a Facebooker just computers that run CentOS they're nothing special storage is a similar thing where for storage you have special replication constraints they take out all of their app because at once so that is also something that's taking a bit longer and finally containers which are currently still a mix of 7 and 8 and we're hoping to make good headways on that this year and be done by the end of the year coming up stream 9 which I am eagerly awaiting to see the sources of these all I have and I will happily take questions here if there's anything left and if there isn't we'll go on this card. Thank you


I'm a nice day of Christmas, but you look good to me. Reusable Christmas gift tags. It's the morning. Hey there, today we're going to make reusable gift tags. As you can see, we have a gift tag on our gift and it's art resin and you can use a dry erase and reuse it year after year. This one we're going to show you today is from a gift card. So we've cut it out. Now we are going to use acetate paper. We're gonna grab some gloves. We're going to mix up some art resin. You don't need a lot depending on how many gift tags you're going to make. So the benefit of making a reusable gift tag is that it is reusable and it helps reduce waste. Now we're gonna take our gift tag and we're going to place it in. We're going to put a little bit of art resin on top of the card and spread it out with your stir stick. Okay, so now we want to cover it up so there's no dust particles that get into it. Then I want to show you one that I actually prepared yesterday. There's a couple of different ideas of different cards. The one thing you want to remember about this craft is that you don't want to wait until a full cure for art resin, which is at 72 hours because it'll be a very hard glass-like finish. This, there's some flexibility to it and so I'm still gonna be able to cut out my gift tags. So I'm gonna grab some scissors and here's the magic. Now, this is the greatest part. Jeff has been a bad boy. We can erase him and give your gift. Boom! They've made great teacher gifts. After Christmas is over, you can take it off the gift and you can even hang it on your tree. So be creative and have fun. Happy holidays. Merry Christmas. Merry Christmas. Police know me dad.


So Cal, it's safe to say you're making this winning look easy, you've come back in three league games and we've won all three of them. Yeah, no, as I was just saying to Simon Parker that I'm just grateful that the team is winning and I'm amongst it and involved in playing and enjoying my time there and enjoying the games that are coming if it can fasten. I just hope we can continue to just keep winning games and get the team back up in the table where they belong. It seemed looking it from outside inwards, it was quite a strong game, quite a gutsy game. There's two good teams going toe to toe. I always knew it was going to be a good game because of their decent team, they got a few decent players in their side and so I knew we had to act our game and focus on our strengths and play to our strengths and I think we're showing today that we've got the quality and we've got the ability to kick on in this league and show the teams in that top off that we're a decent side and we can play and we can ground results out. And it must be nice, obviously the two games that you've been here before, the two away games, Rotstel, Doncast obviously got the two wins, it's nice to show the home fans that winning form as well. There's actually a sign that we're looking to work on as a team and picking up the home form and we've got two great games to look forward to now Wigan and then Blackpool so hopefully we can show the same performance we showed today, take the confidence from today's game into Saturday's game and get another victory.


We all know yeast as the ingredient that makes beer, bread, wine and champagne. But what if we could reprogram yeast to make medicines for us, materials, or make it sense and respond to its environment? This is what synthetic biology is bringing to us. Yeast is our original biotechnology. We've been fermenting alcohol with it for thousands of years. And since the 1980s, with the arrival of GM technologies, we've been able to cut and paste things like human DNA encoding genes that produce things like insulin, the medicine needed by diabetics. But synthetic biology is taking this to a whole new level now. It's fueled by advances in DNA sequencing where thousands of life's genomes have been sequenced, giving us access to the DNA sequence of millions of life's genes, and importantly also in chemistry, where DNA printing can now be done cheaply and rapidly to design. Synthetic biology brings these two advances together so that we can print out the DNA sequence of genes from diverse sources around nature and combine them together in new ways not seen before in nature in organisms that we can work with like yeast. There's so many possibilities when you're tackling with millions of possible genes that the only way to progress in this subject is to think like an engineer would. My research group at Imperial College focuses on turning biotechnology into an engineering discipline, developing the tools that allow things like computer-aided design of DNA sequence, automated DNA assembly, and rapid fabrication and testing of genes in organisms like yeast. When we just combine two or three genes together in combinations never seen before in nature, we can do things like change the way yeast grows, so that we can get yeast to grow in patterns that we define by the topology of the circuits of the genes that are put together, and we can change the timing of when and where those patterns of growth occur. If we start remixing five or six genes from across diverse organisms in nature, organisms like orchids, slime molds that are exotic and make interesting molecules, then we can get these genes to make our yeast not turn sugar into alcohol, but turn sugar into valuable molecules like antibiotics. In my group, we now have a yeast that makes its own penicillin. The engineering principles allow us to do this very straightforward. So straightforward that even undergraduate students over summer can do projects like this, where they can take the genes from carrots that make the antioxidant beta-carotene, insert these into yeast, and potentially now have yeast that can make a more nutritious bread. When you go up to dozens of genes from across nature, the possibilities become enormous. So it's no surprise that dozens, even hundreds of startup companies have emerged that remix genes across nature and get yeast to produce products of high value, things like anti-malarial, medicines, food and cosmetic ingredients. But we can do much better than dozens of genes. What about yeast's own operating system? 6,000 genes, 12 million base pairs, it's genome, and part of the world's largest synthetic biology project, an international collaboration to redesign, rewrite, assemble a synthetic version of the yeast genome to create yeast 2.0. We use a DNA software program which automatically redesigns the genome sequence to add new features, and those genome sequences, we can then email pieces of those to companies that then print the DNA for us and FedEx the DNA chunks back, which we then click together in my lab, add into yeast and gradually turn it into the synthetic version of yeast. Think about where this could go. Think about something out of this world. If all we're doing is designing sequence and emailing it to be printed elsewhere, this is something that could even be done one day in space, maybe in the International Space Station. It's no surprise therefore that NASA is very interested in synthetic biology and investing in this area. Because the beauty of synthetic biology is that the DNA designs go into machines that are cells which are self-replicating. They can grow and we can get product from them. And yeast is an organism where we're very adept at being able to get product from it because of the hundreds of years of experience we have in brewing. Large breweries and micro breweries and home brew too. So one can imagine a future where micro breweries around the world, from the UK to Africa to outer space, could be reprogrammed with DNA printers attached to them so that you could email them the sequences for medicines that are needed when and where they're needed. We're reprogrammed with this DNA to produce the medicines on site. This is a great example of distributed manufacture, something that biology itself excels at doing. But it raises an interesting question. We're used to our medicines being made by big pharmaceutical companies in dedicated factories that can control quality and safety. These key attributes, how can we guarantee them when people are now home brewing their medicines through this distributed manufacturing model? Thank you.


Hello again! Davos is not as snobbish and boring as some may think. Actually there are some amazing parties taking place during the week of the World Economic Forum and some great connections can be set up during this purpose.


Hey everybody, it's Friday, March 27th. We're doing a recap of our trades on the Swing Signal Service. This week we closed the SPX two times, one for about $2,500 and one for about $1,400 yesterday. Today you can see Boeing, we are going to close this. This is probably going to expire worthless, as you can see this iron condor and that should be a good $2,000 or $2,500 trade. Even the others are doing well. Amazon is also going to expire worthless. These are all fantastic trades now. In March already we have exceeded about $18,000 in the Swing Signals program. So even after all this volatility and mayhem in the markets, the Swing Signals picks and chooses the right kinds of trades, the right kinds of stocks and the right kind of strategies because there is a lot of volatility and you have to be able to cash in on this volatility and at the same time time decay. So that's what the Swing Signals is doing. If you want to know more about this program, please watch the end of this video. But it's a great time to join the Swing Signals program with the volatility so high there are incredible opportunities to be captured in the market. Thanks. If you want to join the Swing Trading Signals program, you can go to this bit.ly link, http bit.ly slash 25 swing to get a 25% discount on the monthly plan. You can also come to the OptionTiger website at optiontiger.com and on the home page itself you'll see the algorithm based Swing Trading Signals service. If you click on learn more that will take you to the Swing Trading Signals page and here you can get some more details on it and you can also sign up on a monthly plan for 25% off or an annual plan for 50% off the list price. Thank you.


Welcome to the coronavirus weekly brief. Just a note, we are recording this on one-stage July 29th, rather than on Monday as usual. We're your hosts, I'm David Sturman, and I'm Melissa Sallick-Verk with New America. Here are the headlines you need to know. On July 28th, American Federation of Teachers President Randy Weingarden sets a teachers can strike as the last resort if forced to work in unsafe schools during the pandemic. AFT represents 1.7 million members with 76 percent saying that they would return to school buildings if the proper safety measures were taken. According to the Council of Chief State School Officers, these health precautions could cost between $158 billion and $244 billion in federal funds to ensure school safety nationwide. Democrats recently proposed a bill calling for $58 billion in funding for public schools with no stipulations, while Republicans proposed $70 billion in funds for public and private schools, as long as the majority reopened for in-person learning. As we previously covered in the daily brief, President Trump and Secretary of Education Betsy DeVos have been outspoken about schools reopening despite continued coronavirus surges throughout the country. The coronavirus may cause at least 10,000 additional child deaths worldwide each month due to hunger, reports researchers of a consortium called Standing Together for Nutrition. The Lancet has published a new article by researchers who analyzed estimates on food supply in 118 poor and middle-income nations and also found from their models that moderate or severe wasting of children under 5 years old will increase 14.3 percent or 6.7 million cases, also reported by France 24. Last year's count was 47 million. 80 percent of the 6.7 million cases are children from Sub-Saharan Africa and South Asia, and half are from South Asia alone, reports UNICEF. Wasting takes place when the body does not have enough nutrients that it feeds on muscle and fat and causes one out of every 10 infant deaths across lower and middle-income countries, notes France 24. The models estimate that at worst, children could miss 50 percent of their nutritional care and treatment services, which could yield up to 180,000 children dying as a result. According to the World Health Organization's nutrition lead, Francesco Bronca, quote, the food security effects of the COVID crisis are going to reflect many years from now on, quote, adding, quote, there is going to be a societal effect, unquote. In response to this report, UNICEF, the World Agricultural Organization, the World Food Program, and the World Health Organization contributed to a commentary published in the Lancet that said at least $2.4 billion is needed to help child and maternal nutrition and includes, quote, an essential package of four life-saving interventions, prevention of wasting in children at risk, treatment for children who are wasted, biannual vitamin A supplementation for children aged 6 to 59 months or 90 percent coverage, and mass communication for the protection, promotion, and support of breastfeeding that focuses on caregivers or families of children aged 0 to 23 months, unquote. A report by the New York Times finds that coronavirus deaths might challenge election prospects for President Trump and Republican congressional members in November. Data from around the country suggests that coronavirus deaths are linked to President Trump's approval rating, where an increase of local deaths from the virus shows a lower approval rating for Trump and a higher favorability for presumptive Democratic nominee Joe Biden. While compiling county-level data from around the country is difficult and results depend on the region, the nearly 150,000 American lives lost to coronavirus will likely have a considerable impact on voters in November. Research dating back to the Civil War and as recent as the wars in Iraq and Afghanistan shows the similar negative correlation between wartime deaths and electability, although Republicans are still pulling well in states including Wyoming and throughout the Great Plains, recent coronavirus surges in swing states including Georgia, Arizona, and North Carolina may prove a challenge for Republicans. Antiviral immune proteins called interferons may offer a chance to stop COVID-19 from escalating into severe cases, but timing may be crucial to whether that treatment helps or harms. These immune proteins suppress viral replication early in disease, right scientific American, adding, yet if they are active later, some scientists think they can exacerbate the harmful inflammation that forces some COVID-19 patients onto life support. Several trials of interferon therapies are ongoing. British pharmaceutical company Synergyn announced that their inhaled interferon, quote-unquote, greatly reduced the chances of severe disease and hospitalized COVID-19 patients reported by both Biosentry and the New York Times. Their results are unpublished and their study is small, only 101 people. That larger studies are needed to confirm whether the drug is truly effective, but the results show that odds of severe disease were 79 percent lower in patients who received the drug than in those who did not. Several pre-clinical studies in animals and human trials suggest that interferons are a promising avenue for COVID-19 treatment, Report Science Magazine. Earlier this year, a preventive trial in a hospital in China's Hubei province gave daily interferon nose drops to over 2,400 medical workers and found that none of them came down with COVID-19. And at Tehran University of Medical Sciences, a team found that subcutaneous interferon injections lowered mortality and increased the number of patients discharged from hospitals. Both of the aforementioned trials were posted as manuscripts on a pre-print server. The coronavirus pandemic has severely limited the hush, the annual pilgrimage meant to be carried out once in a life of any Muslim who is able. And by extensions of various industries that support the influx of millions of people to Saudi Arabia have been impacted. During a normal year, the hush brings in over 2 million people to Islam's holiest sites in Mecca, Saudi Arabia. But this year, because of the coronavirus, the kingdom limited participation to only 1,000 people who are already living there. This has left Somalia's livestock breeders, traders and exporters who usually supplied the kingdom with millions of cows, camels, sheep and goats needed to feed the pilgrims. With a sudden drop in demand according to a report by the Washington Post, livestock exports make up three quarters of the total exports for Somalia. And 70% of those exports are sent to Saudi Arabia in the months leading up to the hajj. Now, many livestock sellers are left with animals that no one wants to buy, that they accrued earlier in the year to increase their herd, with the expectation of being able to sell the animals and repay the loans. To see our daily brief, go to the address in our show notes and follow us on Twitter at New America ISP. And tune in next Monday for our next episode.


So in this video, I want to change your perception of what a drop shipping, a stereotypical drop shipping business can look like. When you mention the term drop shipping to people in Facebook groups, a lot of people will cringe and say, avoid, it's a scam, it doesn't work, it's cheap, plastic-y products that take weeks to arrive from China on tiny little profit margins and super low quality. That couldn't be further from the truth. However, if you still want to go with the drop shipping business model, but avoid those types of products, then this is the video for you. Today I'm going to show you a drop shipping store that's currently for sale on flipper.com for $136,000. They employ the drop shipping business model, so they're not keeping stock of all of their products. However, they are not coming from China and they are not cheap products either. They're quite a successful business. They've been in business as we can see for three years and they have an average monthly profit of just over $4,000. I'll give you a bit more contextual background information about these guys in a second and what you'll soon see is that over a relatively short period of time, they've been able to build up a very successful business that requires little to no time each week other than order fulfillment. And based on the poll that I put out last week, asking people what sort of money they would like to earn from their drop shipping business, then the majority of the people watching this video would be more than happy with a business that makes this sort of money and offers this level of freedom. So the business is called Tilly and TedHomeware.com. It's a turnkey e-commerce business in the home and garden niche, which boasts profit margins of 75%. The site age, as we've already been over, is three years. Now, some people might be thinking three years and it's only making four grand a month. I don't know of any typical job or typical level of employment where your income would go up by four grand a month within three years if you know differently. Make sure you let me know in the comments section. So in my opinion, if you ask me at least, I would say this is still a pretty successful business even given the length of time that they've been in business. Just to confirm, their monetization methods via dropshipping, they use Google Analytics, Shopify, and Xero is a Xero, obviously being the accounting software and their primary expenses then for last month was $1,600. Before we jump into the products then, I wanna show you some more information. So one of those things is the revenue and profit from the last 12 months. This is still a current and active business. A lot of the businesses you'll come across on Flipper.com, they'll make a ton of money in Q4, then Jan Feb March when sales dip off. They'll want to kind of offload the business but still try and sell it at the numbers they were doing in Q4 but it doesn't quite work like that. Except for these guys, their money really is where their mouth is because as we can see, even through Q4, before Q4 and even as of last month or a couple of months ago, they were still doing over $5,000 in profit for the month. Let's jump onto the website then, take a look at exactly what their store design looks like. Store design, again, I did a poll a couple of weeks ago asking people what they think is the least important or to vote, what is least important, what's most important when it comes to a business. And it's not the first time I've done a vote and it's not the first time that your Shopify store has come at the most least important, which to me doesn't make sense because it's the first impression with every new person that comes onto your business.  So I guess what I'm trying to say is don't skip over or take for granted what your Shopify store looks like. There's always work that can be done or always split tests that can be done to try and improve your conversion rate. So straight away we're greeted with a 10% off discount. This is actually something I recommend everybody do regardless of how expensive your products are. And this is the homepage, so straight away it gives off that kind of soft, feminine kind of touch that homey feel. So to speak, they've even got the pink fonts at the top. To be honest, I'm not a big fan of this because I mean, my eyes aren't great but I'm having to squint to kind of see what they are. So if it was me, I'd certainly be looking at changing that. And then moving down, again, a very kind of textbook, typical look of any particular Shopify store. But the first thing that probably jumps out to you is you've not seen this store on AliExpress before, you've not seen this store or these products. These guys are most likely working with lots and lots of different independent and local businesses, maybe even not local, but certainly nationwide, you've probably seen the prices as well. The fact that it's in great British pound, so it is a UK based business, I would guess they're working with a lot of private and independent companies. That sell these sorts of products and have some sort of deal or arrangement for them and say, hey, can we advertise or can we put your products on our website? We'll sell them at the retail prices. We'll sell them at the prices you tell us to sell them at and then whatever we get orders for we'll pass on for you to Dropship. This is also confirmed in the operations of the business where it says if the order is by one of the Dropship suppliers, the order is passed for them to fulfill. So basically this business or whoever's running it hasn't got a ton of these chairs in their garage or in their living room stocked up. These will be kept in a factory somewhere by the independent business that owns them. A massive advantage to doing things like this is obviously when you're selling a product, let's just take, well, these chest of drawers for example, 600 pounds. The profit margin on them is probably a couple of hundred. And when you've got a couple of hundred pounds worth of room to work in for your advertising, for your CPA, the cost to acquire a customer. Obviously you can reach quite a lot of people for that sort of money. So you've got a little bit more room to play with I guess or a little bit more experimentation and testing to do and still be able to make that profit. The other advantage to working with independent companies and suppliers is they usually film and take their own content because they're an individual business in their own right. So as long as they're happy to of course, you can kind of piggyback off the back of that, take the content that they use, put it on your website and it's like free content for you to use and advertise your business with. And obviously it's a win-win all the way around because if you get the order, you win by making your money and the supplier wins obviously by being able to fulfill the order and make their money as well. Something else just to point out is this free delivery. Well, not the free delivery in fact, but what it says later on, which is the buy now, pay later with ClearPay. This is something I recommend everybody have in your business, whether you're drop shipping cheaper products or selling more expensive ones. It's a great way of kind of piggybacking off the reputation of names that people feel comfortable with. If you go into ASOS and see you can split with Clana or ClearPay over the course of three months and ClearPay or Clana is this household name that everybody's comfortable and familiar with and then they come onto your website and see that same name. Instantly you kind of your brand piggybacks a little bit off the reputation those companies have already built up. Let's jump on to the Facebook ads library then and see how they're advertising these products, how they're making the money. And we'll start off with this one, which is a very simple carousel ad. As you can see, it's original photography of the product in a nice setting. I think they could probably do a little bit of a better job if I'm being honest with their Facebook ads. There's no need to put hashtags and things like that in there. But at the end of the day, who am I to argue? They're making a decent amount of money each month. So it's one of those things. If it's not broke, then it doesn't need fixing. The best products, the most successful ads on Facebook are always those ones that are selling something unique, something original, something that people haven't seen before. When people are scrolling through on Facebook, they do so for so long each day. They see so many things, they see so much content that if they see something that they've already seen before, they're probably just gonna scroll right past it. However, if they come across an ad like this and they've never seen this particular product before, instantly it's gonna kind of like make them intrigued into what the product is and want to watch the video because it's something they've never seen before. And this is where the majority of the traditional stereotypical dropships go wrong is they'll sell the same products as everybody else using the same content as everybody else. So when you're trying to advertise that one product that maybe 10 dozen other people have tried to advertise and put ads out for a similar content, your audience might already be used to seeing that same content and seeing that same product. So when they see your ad, they just skip right past it because they just assume it's the same thing. When, to be honest, it pretty much is the same thing. Whereas if you're taking the time to order the product yourself or buddy yet get it shipped to some people who have experience taking content, filming content, essentially creating original content for you to use for your business, then you significantly increase your chances of getting the eyeballs on and stopping people in their tracks when they're scrolling, getting their intrigue in them watching your video and then that way they become much more likely to buy your product. Back to the video then, it's a very simple video. Anybody could create a video like this simply using an iPhone. It's just someone in a nice setting and putting together this flower bouquet obviously in this very nice looking fars as well. Let's take a quick look then at the final ad, another video ad and it's just kind of like a drive by that's not the right term obviously but it's just what come to mind. It's like a slide show or drive by, I'm just gonna stick with drive by of all the different pieces that come in this furniture collection and again as we've seen before they do not have a factory or garage full of these things. These will be kept in the independent businesses that are selling them themselves in their own factories and once they get in order for it they'll just simply be passing it on so essentially they are still taking advantage of all the benefits of dropshipping. If we come onto their social media pages then just to finish the video off I think it's an important thing to do. Again it's a place where I see a lot of people neglect their businesses. If you've been running ads you are probably already aware of this that people will click who's running the ad. Basically they'll end up on your Facebook page they'll have a look around and maybe even end up engaging with some of your earlier posts.  So when they come onto a Facebook page if they see things like you have your shop set up you have your location on you have a telephone number you have an email address you have great reviews gorgeous homeware or arrived in good time and basically people evidence people have shops with you and had a good experience. They come on and they see recent original content as well so from May 18th if we go down we can see it's all in the same kind of uniform style that's in keeping and matching with the brand it gives off that impression of an active professional and legitimate business. And so with that being said to wrap the video up and guys the message I want you to take away from this is if you've been trying the traditional Chinese I express type form of drop shipping it hasn't been working out with you or perhaps something doesn't quite sit right then do your own research and take a look at these guys yourself have a look nationwide at the types of products that are super high in demand see if there's a lot of private suppliers that you're comfortable with contacting and see if you yourself can set up a similar business like this. Yes it's gonna be a lot slower to get started yes it's gonna be a lot slower to get results but as we've seen here over the course of three years they've been able to build up a very healthy income from a business that probably takes them no longer than maybe five or 10 hours a week because at the end of the day the alternative is that you don't do anything and I would probably bet my bottom dollar that in three years time the job you're working now won't be paying you an extra four grand per month probably won't even be paying you an extra a thousand pound per month so whether you do this or the traditional type of drop shipping then my advice is just to get started give it a go because you never know what's gonna happen and how things can change for the better. On that note, thanks for watching guys hope you enjoyed it and I'll see you in my next video on Wednesday. Cheers.


So let's take a look at something called a rational expression, and a rational expression is the quotient of two polynomials. So for example, 3x plus 5 over 2x minus 7, it's a quotient of 3x plus 5 divided by 2x minus 5. Both of these are polynomials, so that's a rational expression. Likewise, x squared minus 7x plus 8 over 3x minus 5, this is a quotient of two things, both of which are polynomials, so this is a rational expression. x plus 7 over 3 over x minus 7, well, it is a quotient. It is a quotient of two things, but one of the things is not a polynomial, so this is not a rational expression. Now, I'll add a small qualifier here. It is possible. It is conceivable that we can do some sort of algebraic simplification on this and produce a rational expression, but as it's written, this is not a rational expression, and it's a philosophical point, but as it's written, this is not a rational expression, even though in potentia, this could be a rational expression. For us, we are, for this point in time, concerned with what is and not what could be. For what could be, that's when you take calculus. Well, again, algebra is a generalized arithmetic, so it's useful to think about rational expressions as being equivalent to fractions, and if you have a fraction, the one absolute rule that you have from arithmetic is that the denominator can never be equal to zero, and this is not ordinarily a problem. If I have a fraction like 3 over 5, I could say, well, we absolutely cannot allow 5 to be zero. 5 is never allowed to be zero, and well, that's not really a problem. But the problem arises when we look at rational expressions, because the denominator of a rational expression is a polynomial. It's possible that there might be some values of x that make the polynomial equal to zero, and these are the forbidden values, and we have to be careful that we identify these early. And so as a matter of habit, as a matter of something you automatically do when you are confronted with a rational expression, the first thing you really want to do is to identify the forbidden values and exclude them from consideration. So for example, let's take the rational expression, x squared minus 2x minus 5 over x squared plus 4x minus 12, and see what values of x we want to exclude. So we have to exclude any value of x that makes the denominator equal to zero. So a very common strategy is we see what makes this happen, and we forbid that from occurring. So I want to find where does denominator equal zero, and this is a quadratic equation, so we waste time trying to factor. We use the quadratic formula because we have a nice, fast, quick, efficient way of solving any quadratic. And I'll substitute my values of a equals 1, b equals 4, c equals negative 12. I substitute those into the quadratic formula, and after all the arithmetic does settles, I get my two solutions, x equals 2 or negative 6. Now, since x equals 2 or negative 6, solve this equation. x equals 2 or negative 6 will make the denominator zero, and I have to exclude them. I have to forbid that possibility. x cannot be 2 or negative 6, and I'll write that exclusion this way. Well, what about simplifying things? So a rational expression is like a fraction, and one of the rules I have for fractions, one of the important rules I have for fractions, is that if I have a common factor in numerator and denominator, then I can drop that common factor, and so if I can factor numerator and factor denominator, and if it happens that there's a common factor in both, I don't need to carry it over. Well, both are quadratic, so we should always use the quadratic formula to find the roots and then factor. So I need to find the forbidden values for the denominator anyway. I'm going to want to find the values that make this zero. I'm going to need to find the roots anyway, so it's not a great hardship. So here's my quadratic equation, 3x squared minus 11 plus 6 equals zero. Denominator equal to zero. I have my quadratic with a equals 3, b equals negative 11, c equals 6, and I'll substitute those values into the quadratic formula. I'll let the dust clear. I'll do some arithmetic. I'll do some arithmetic. I'll do some arithmetic. I'll do some arithmetic, and I get my two solution. 11 plus 7 over 6, 18 over 6, 3, or the other one, 11 minus 7 over 6. That's 4, 6, otherwise known as 2 thirds. Now again, once I know the roots, first of all, I know that these are forbidden values. I cannot allow x to be 3 or 2 thirds, but I also know that x minus 3 and x minus 2 thirds are going to be factors of the denominator. So my denominator is going to look like x minus 3, x minus 2 thirds, and here I've made that note. I cannot let x be 3 or 2 thirds. Now, it's important to write this down because we're about to do something that's going to make that very critical. Now again, this gives us our variable factors. There may be an additional constant factor we need to complete the factorization. And in this case, you might note that if you expand this out, you get an x times an x, you get x squared. We really want a 3x squared, so we need a constant factor of 3 thrown in to complete our factorization. So there's our extra factor of a constant. Well, that numerator, we can do the same thing. We can find the roots of the equation x squared minus x minus 6 equal to 0, and I can solve this using the quadratic formula. Again, a equals 1, b equals negative 1, c equals negative 6. I drop those into the quadratic formula and I let the arithmetic dust settle. And after all the dust settles, I get my two roots, 6 over 2, 1 plus 5 over 2. The other root, 1 minus 5 over 2, negative 2. And the solutions are x equals 3, x equals negative 2. And the root theorem says solutions correspond to factors x minus 3, x minus negative 2. And so the numerator here factors as x minus 3 times x plus 2. And now I look for common factors in numerator and denominator. And because, and here's a very important thing to be careful with, because I have a product in the numerator and a product in the denominator, I am allowed to drop common factors. If you do not have a product, you cannot drop the common factor. So I do have a product in numerator, I have a product in the denominator, and so my common factor will drop out and I can cancel it out and leave my new expression this way, x plus 2 over 3 times x minus 2 thirds. And this is a perfectly good form to leave it in. I can combine this constant factor 3 with the denominator expression or not, your choice depends on what you want to do. So maybe we'll clean it up a little bit and so I'll multiply this here to get 3x minus 2. Now here's a very important thing to realize here. This prohibition, x cannot be 3, x cannot be 2 thirds, still holds. So this expression is this expression, as long as x is not equal to 3, not equal to 2 thirds. And the reason we still have to include this prohibition, these forbidden values, is that I can let x be 3 in this expression. If x is 3, there's no problems. If x is 3, there are problems on this. And I don't want no problem to be the same as big problem. So I include that prohibition. I still can't let x be 3. As long as x is not 3 or 2 thirds, these two expressions are equal. If x is 3, then these two expressions are definitely not equal. If x is 2 thirds, both of these expressions are meaningless.


Ukraine warns of possible provocations, sabotage actions at border with Belarus. Commander of the Joint Forces of the Armed Forces of Ukraine, Lieutenant General Seriai Naiv, does not rule out the possibility of provocations and sabotage actions at the Ukrainian-Belarusian border. The relevant statement was made by the Joint Forces Command of the Armed Forces of Ukraine on Telegram. According to Naiv, the situation at the border with Belarus is fully controlled by Ukrainian forces, and no rapid changes are expected there. Naiv mentioned that Russia's ground component had been fully withdrawn from Belarus and is now part of the reserve of the Joint Grouping of Russian troops involved in the enemy's offensive in the Kupiansk and Lyman directions. However, a series of CSTO training exercises have been scheduled within the territory of Belarus for September 2023, and they can be used to legitimize the increase in military presence. As Russia failed to achieve its strategic goals, Naiv does not rule out that the aggressor will continue to seek for the new reasons to resume active actions from the northern direction. Therefore, the enemy may organize provocations and sabotage actions at the Ukrainian-Belarusian border. At the same time, Naiv emphasized that no signs of forming strike groupings within the control area of the North Operational Strategic Group of troops had been detected. But, in view of potential risks from the territory of Belarus, the Ukrainian side is taking measures to increase its counter-sabotage and defense capabilities.


Ladies and gentlemen it has been five months nearly six months Which is nearly half a year since we have had a character in FNAF AR. It's been nothing but skins Yeah, we had 8-bit baby, which technically is their own character, but like Who who the heck counts 8-bit baby as a character in that I skin. Let's be real here and for some reason Flamethrower Bear Ender was also maybe its own character, but then again It also might just be a bug with the workshop Anyways, that is all besides the point. It has been five months again since March where we had Mangle since we have had a returning character from the FNAF franchise that was in FNAF AR And that all changes later this month with the addition of FN lefty. You heard me right boys Lefty from FNAF Pizzeria Simulator FNAF 6 is coming into special delivery Pog so let's actually hop into what's going on because me just saying alright guys Lefty is coming into the game. You might not believe me Well take a look at this email that players are receiving it was posted today on August the 15th 2020 and it's titled It is from an unknown source and it is directed to us and the email says it's oh so quiet So let's be real here. It's obviously lefty, right? It's gotta be lefty lefty's lines from Ultimate Custom Night always involve him her Whichever one you want to classify lefty as they're always going And then they have their line so clearly this is fucking left And this is not the only piece of evidence we have for lefty being added into the game So if guys don't remember back in late November when the launch trailer for FNAF AR went up There was a lefty easter egg and because there's been so many trailers for special delivery Let me say that it was the again the launch trailer where we are in our house We have all the characters appearing in our house right Barney and BB are outside like the the sliding glass door Cheeks in the kitchen for the chases us down the hallway out of our house that one right it had a lot of easter eggs in there It had some faded text it had some it's me writings It even had plus trap on a chair, which by the way, he's not in the game yet He's not even the character coming out. Oh my god It also had a glitch trap and I think maybe even a purple guy easter egg in there as well And like I just said yes, it had a lefty easter egg And yet we still have more evidence because again back in November Maybe even early December the voice actress for lefty posted this so this is the post it was posted on instagram And again, this is the voice actress for lefty So the picture is of a audio file that says FNAF underscore lefty and the caption is oh my goodness So happy to finally get to announce that lefty is back in another installment of five nights at furdies So so happy to once again get to scare the crap out of all of you game comes out this fall play and be terrified So again, this was back in the fall of 2019 So this lefty character has been in development Or at least they've been thinking about adding lefty into the game for a really long time also Remember not too long ago when lefty's profile picture was leaked in the game. That's right We knew that some of his assets like his profile picture Maybe even some of his lows were in the game's files But that was the first time a couple weeks ago when we actually saw them in the game itself Not just in the files Actually in the game where players can view it and all you guys said that I was I was looking too far into it But here I am right now telling you yes, I was right So now that we have that out of the way, let's talk about possible mechanics So it is exciting that we do know that new voice lines for lefty have already been recorded by her voice actress Apparently a lumix have had these files for a really long time because again The voice actress sent them to a lumix all the way back in the fall I will say lefty is kind of a weird choice because up until this point they have been going in Order of the games right they had the fnaf one gang They did have a few loose characters like bb and circus baby in spring trap But it was mainly the fnaf one gang right yet And uh one freddy bonnie chica foxy and then when they started releasing new skins It was the toy anotronics toy chica toy bonnie toy freddy mangle So I am a little bit interested to figure out why they all of a sudden are going from fnaf 2 all the way up to fnaf 6 Maybe they just want to have at least one character from each game in the game And then they can move on to other characters again. I don't really know Anyway, so going back to mechanics I do feel like maybe it'll have something to do with a music box Because really thinking about it the puppet or the marionette is inside of lefty That's the whole point of lefty's existence And the puppet is very fond of the music box same thing with lefty because in ultimate custom night Lefty's mechanic was that they could be sued by using the global music box So maybe every now and then we'll have to wind up a music box I'm not sure how that mechanic would truly walk in the game Or maybe they'll just do something completely different. Maybe they'll have a salvage mini game Not like the actual salvage mini game, but maybe they can try and incorporate that In fnaf a or somehow we have been asking for new game modes For a long time at this point Then again the a or section does already have a taser that you shock the characters with so maybe Maybe that idea is off the table. I don't know. It is very interesting. Um, so I will say lefty is not coming out this week They are coming out the last week of august this week apparently alumix is bringing back Old skins from previous events. Alumix did release a series of tweets The other day, so I'm gonna read them off right now, but f a or august mini update one of two We know that you're all really excited for the new character that's coming this month So I wanted to make sure everyone remained updated on the special deliveries remaining in august for knife They are august update two out of two flaming spring trap is the last sizzling sum of skin You told us that you've been missing animatronics from previous events So a few favorites will be back next week look out for clues on the next character They're coming the last week of august and we all know that that character is lefty Looking through the comments a few people are speculating that it would be plus trap some even say below I just came across one that wants below. I guess you're gonna have to wait a bit longer for that But again, very interesting that they're going with lefty. They haven't teased again. We went through all the evidence They've been teased in the past, but i'm still very intrigued why they went with lefty to be fair We had a feeling that they probably weren't going to go in order because if it wasn't lefty I think we could all agree that it would be plus trap Which of course is a fnaf 4 character not a fnaf 2 or 3 character And again other characters that are speculated for the game or Funtime Freddy, Ballora, Scrap Baby, the Nightmare and Matronix So yeah, apparently they're not going to be going in order with the games at this point going forward But i'm still unbelievably excited for lefty again It's been five months not including 8 bit baby and flamethrower bear endo because those guys like They're not characters. Come on.  They're technically characters, but nobody come on. Nobody guys Nobody classes them as characters five months back in march. We got we got mangle along with shami shamrock furdy skin It's been five months since we've gotten a character and it's finally Finally happening. We're finally getting a new one this august the end of august. I'm so excited It's also interesting to theorize what they could do with skins for lefty personally I think the sign, you know when you've already bought him and then you come into his salvage minigame and the signs there I think if they add that sign as a skin for lefty, that would be amazing, right april fools Come on alumix. I'm basically giving you ideas. Anyways, that is about it. I'm sure more emails will come up Leading up to lefty's release, but I mean we already know it's lefty. So there's no reason to do More videos on it. I'll probably post them in the youtube community tab. So keep an eye out on that. Yeah, that's it for me right now Thanks for watching. I literally just posted a video before this playing a fan game called blank. It's really cool I loved it a lot. Go check it out. So yeah, I'll see you all on the flip side. Goodbye


Described in 1964 as a lady with a dream, Mabel Bradley Payne was that and more. A pioneer of Columbia's preservation movement, she recognized the importance of the history of our city as embodied in the buildings that make it. Throughout her career and time in Columbia, she fought to save numerous parts of our city's history. Best known today for her work to save the Robert Mills House, Mabel Payne's efforts with the City of Columbia had a lasting impact on the preservation of historic properties throughout the city. Born in Abbeville, South Carolina, Mabel Payne moved to Columbia when she was 13, spending some of her formative years here. While in high school, she found her first passion, the stage, and she acted in several plays. Following her graduation from Columbia High School, Mabel Payne moved to New York City to further her study of acting. During her time there, she primarily worked as a teacher and married her first husband, Vasyl Kalmikov. Although her passion for preservation had not yet formed, her strong affinity for historic buildings was readily apparent. Mabel Payne sought out older residences in New York and even lived in a 19th century Chelsea townhome, formerly owned by Clement Clark Moore, author of The Night Before Christmas. When she returned to Columbia in 1936 after the death of her husband, she found that many buildings she had admired on her walk from Columbia High School to the University Hill neighborhood had disappeared. A trend she'd continued to witness over the next few decades. Upon returning to Columbia, Mabel Payne ran a progressive preschool in Maxi Gregg Park in the late 1930s. And from 1939 to 1941, she worked as the business manager of the town theater and director of their children's group. Mabel Payne once again left Columbia in the early 1940s and married her second husband, John Payne, in 1947. They lived in New York City, Alabama, and Virginia. And during her time in Virginia, her passion for acting and appreciation of history translated into a new role at Colonial Williamsburg, where she worked as a hostess, interpreting history in colonial dress for tourists. This work would have a lasting impact on her career and her worldview. In 1956, Mabel Payne moved back to Columbia one last time and took a job with the city as a tenant enforcement officer for the Urban Rehabilitation Department. Working with homeowners who participated in the rehabilitation program as part of the substandard housing ordinance, she saw firsthand how effective reinvestment into old homes could be. At the front line of the urban renewal program, she also saw how demolition threatened to destroy large swaths of our city's history. While she had little power to prevent the demolition of historic properties, Mabel Payne worked tirelessly to photograph buildings slated for and threatened by demolition. In essence, she created Columbia's first preservation records. Some of these photos, now housed at Richland Library, are the only images remaining of these early Columbia buildings. Some of these buildings include the William Glaze House on Park Street, 1502 Richland Street, 1615 Hampton Street, and the House and Office of Dr. Clifford Oliveros, the site of which is a parking garage today. Recently, city preservation staff rediscovered a group of 35 millimeter slides, including photographs taken by Mabel Payne and those who assisted her in documenting historic structures. These previously unseen photos include color images of lost Columbia buildings. These new slides will be uploaded to the Richland Library, Walker Local and Family History Room digital site in 2022. Some of Mabel Payne's first efforts to save historic properties beyond documenting them in photographs were largely influenced by her time in Williamsburg in the early 1950s. She hoped to create a mini Williamsburg in Columbia by moving historic buildings to the area around the governor's mansion, which, at the time, was feeling the pressure of urban renewal and rapidly losing historic structures. She later had a similar idea for the land surrounding the Robert Mills House, which was proposed for the construction of townhomes. While ultimately the dream of a safe haven for historic structures at either site did not come true, the governor's mansion area became one of Columbia's first historic districts, largely due to Mabel Payne's efforts and attention in the area. The Robert Mills House remains a pristine example of historic Columbia as well. Mabel Payne was also instrumental in the creation of the city's first landmark list, a list of properties throughout the city worthy of preservation. As the head of the city's historic division in 1966, she worked with an architecture professor from Clemson University to survey historic resources in the city, adding to the landmark list and prioritizing sites for preservation. While the Historical and Cultural Buildings Commission, which she staffed, generally only had the power to delay the demolition of properties on this list, there were several instances where the delay led to properties being saved and, in some cases, relocated to be preserved elsewhere. Examples include the Robert Mills House, Chestnut Cottage, Caldwell-Boilston House, and 1518 and 1522 Richland Street, all of which were preserved in their original locations. Other buildings that were saved by relocation include an 18th century log cabin moved from River Drive to Sesquicentennial State Park. 1921 Park Street, which was moved to Windover Drive, and the French Consulate Building, which was moved several times but eventually relocated to the old Shandon area. As an early voice for local preservation, Mabel Payne's efforts to preserve historic buildings and the history of our city has had a long-lasting impact on the fabric of the build environment in Columbia. Preservation at the city level has been built upon the foundation of her work, and we remain indebted to Mabel Payne and her pioneering efforts to save Columbia's history.


Hi, this is Hans van der Klaas Senior Lecturer at IHC Delft Institute for Water Education. In this video we are going to make a fun map, not for a particular reason, just for fun, a Lego map of the Rurc catchment. I have combined knowledge from other videos and tutorials that I found on the internet and applied it here to the Rurc catchment. What we need is a polygon layer with the boundary of the catchment and a digital elevation model. The first step is to create a regular grid. You find it under the research tools, create grid. The grid type is rectangles. We want rectangles to get this kind of raster. And I use the layer extent from the Rur boundary polygon layer. Now we need to give a horizontal and a vertical spacing. We can use the measure tool to estimate the size of our Lego bricks. And I think here around three kilometers would be okay. So I switch the units to kilometers and I use three kilometers for the horizontal and the vertical spacing. And I run it and it creates the regular grid with the three kilometers spacing. We use select by location to select those pixels that intersect with the Rur boundary. If we would use clip, it will also clip to the boundaries and we will use the rectangles at the boundaries. So now I have a selection of those grid cells that intersect with the boundary. If I invert the selection, then I can remove it and we now only have those grid cells that overlap with the boundary. The next step is to get the mean elevation per grid cell. I use the zonal statistics. So the input is the DEM and the vector layer is the grid. I can make an output column prefix that I call DEM and I want the mean value. Let's check in the attribute table and I see there the mean values of the DEM for each grid cell. Now we are ready to do the styling. In this case we use the graduated renderer and we choose there the DEM mean field and I'm going to use the same color ramp that I used for the DEM and this is Vicky Knutuck's one and you can use a distribution that you like. I use here natural breaks, janks in five classes. Now you can double click on a color and refine the styling to look like Lego bricks. Therefore we need to add three more of these symbol layers. So in total we have four. Let's get back to the lowest one which is the shadow and first do the one that represents the grid color. We can sample the color from the map and I just need to change the properties of the stroke, make it black and then 87% opacity and for the shadow that's the lowest one I'm going to change the fill color also to black and I use a 54% transparency opacity. Use no pen for the stroke style and I give it an offset of 0.45 for both X and Y and now you can already see in preview a little shadow that is dropped. Now we need to change the first two symbol layers. You can use the geometry generator but it's easier to use the centroid fill which automatically sets it to the centroids of those grid polygons. I change the simple marker of the first one to take the color sampled from the legend. I change the stroke color to black and the opacity of 87% and the stroke width of 0.1 and for the second symbol layer I'm going to use also the centroid fill and that will be then the shadow of the centroid. Also make it black, 54% opacity, no pen and I'm going to give it an offset of 0.3. We have now a little shadow and do okay and I see here that the centroids with the dropped shadow show up. It's still a bit small and it depends on zoom level how it looks like so we're going to fix that double click and I'm going to change the units to meters at scale and I want them to be half of the pixel so 1500 meters and the same for the shadows. Okay now they are a bit bigger, looks a bit more like Lego bricks and when I zoom in and out they also stay the same. So I can apply this now to the other colors, copy the symbol and paste it and now the only thing is that I need to sample the colors from the legend and I can take it here from the DEM but if you don't have that then before going into this procedure you could also duplicate the layer and then sample it from the duplicated layer. Now there's only one thing that we can tweak and that's the symbol levels. It's the order of drawing the different symbols and now they're all drawn at the same moment so I'm just going to give them a continuous number starting from 10 and increase them. This is to create the effect that the blocks are a bit stacked with the shadows and there we see the effect so the higher blocks look higher than the lower blocks. Now let's create a print layout, a new print layout, call it Lego and let's make a map. First I need to go to page properties and make it portrait, zoom to the extent, add the map, leave a bit of space for the title and resize it so the map shows up nicely in the center. Let's add a legend, let's remove some of these items switch off auto update and now we only have the DEM left over, let's call it elevation. Now I would like to have those symbols as square blocks so I'm going to make them the same size 7 by 7 and it looks more like the same bricks. Create a scale bar, of course it needs to have nice colors too, go to fonts and colors and let's sample some nice colors from the map and let's remove the line, that looks nice. Let's change the font, one of the few occasions that I can use the comic sans serif, let's make all the text red also for the legend, it has a subgroup heading, let's also change that to comic sans serif and the item font the same, change the color to red, give it a title, change the font of the title to red and we need a north arrow and I'm going to use a picture for that little end to indicate the north and there it is, our map is done. So just for fun, an easy way to create Lego maps, I hope you've enjoyed it, if you like to see more videos you can subscribe to my youtube channel and for free GIS tutorials go to GIS opencourseware.org.


I am very happy to participate as a speaker at the Exchange for Media digital conference that is around the subject of digital and what digital can do. Hi, hey, it's Tamara McLeary and I just wanted to say I'm so excited to be keynote speaking at this year's Exchange for Media digital marketing conference, TechMod. Exchange for Media puts on the TechMod conference and the Indian digital marketing awards every year. It's become one of the top conferences in Asia and around the world. What are we going to talk about? Well, a lot of people you'll meet at the conference will bring to you the latest and greatest in digital technology. But what I'm going to do in the keynote and the workshop if you have time to join me there is to explore what it takes to you as a digital leader, as a digital market, as a digital expert to be more successful. First, very importantly, we have to understand that it is not about digital marketing, it is marketing interconnected. That's first important. I had no idea it was such a large forum so well attended. The energy and the youth is of course something that I should have expected and I'm always pleasantly surprised. But the one thing that has struck me today is a number of entrepreneurs who are striking it out on their own and trying to build businesses using technology and digital. That to me is super exciting and so I think the best is yet to come. It's not just up to creatives to create great stories but when you're able to incorporate data you can get even better results as she showed in many examples. The topic is so relevant to talk about how to communicate through digital communication. So very positive.