Are we live? Yes, we are. Hi, guys. We are here with Tyler at Futural Hall. He is a resident technician. He's going to walk us through some housing services today. Good afternoon, everyone. Thanks, Chris, for having me. And thank you, Sophie, for live streaming this. Yeah. Like Sophie said, my name is Tyler. And I'm a technician here at University Housing. We provide technical and network support for your students living in our residential dorms. Over here on this laptop, I can show you some of the services housing provides for the residents in our dorms. So you can visit this webpage, housing.york.edu, and then head over to services. And on this page, you can see all the services that we provide for some of our students, which include Cox Cable, Laundry, mental health services, mail packages, et cetera. Today, we'll be going through some of these and going into detail so you guys can have a better idea of what housing provides for your students. Great. And we have about 11 people tuned in today. If everyone wants to tell us where they're from, that'd be cool. Let's start with me, I guess. I'm from Portsmouth, Arkansas. So I'm kind of local around here. And I've been up and down in Portsmouth, Arkansas basically my whole life. What are you studying? Computer science. Very cool. So tell us about the cable system. Great. So over on my right side, you can see we have our cable hooked up to this monitor, and it's functioning. We provide Cox Cable. I can get this remote to work. We have many different packages included with Cox Cable. You can get more details on our housing page under the Cox tab. You can see here there are many different channels you can choose from to watch. It also comes with Cox Contour and HBO. Nice. And we have a couple of people from Houston, someone from Franklinville, New York, and someone from St. Louis. All over the country. Identity tune in. Sophie, if you come over here behind, I don't know if you can see, but in our rooms there will be a Cox Box mounted somewhere. In this room specifically in future, it is behind this desk. And connected to the Cox Box is an HDMI coax cable, an IR extender for your remote, and a power cable. If you need help installing any of these devices, you can contact us and we'll send out a technician to come and install it for you or provide you a guide on how to install it. And for equipment that you need such as remotes, HDMI cables, or power cables, this year the front desk will actually have boxes of supplies that you can go to, like the front desk, and ask whatever you need instead of having to have a technician to come out because of these new COVID-19 implementations. That's great. And we also have Cameron from Yalville, Arkansas here. Yalville. We like Yalville. See, on this Cox page it also lists physical addresses for your dorms, which is different than your PO Box. That is very important to note. Typically you won't have to contact Cox support yourself. You can contact resident and we will do the communication for you. Some creek houses, dunking apartments. Also interestingly, you can request additional services from Cox. I believe the student would pay extra for those services. Yeah, for DVR and stuff, yeah. But if you would like DVR services and anything else you can contact us and we can get you in touch with Cox. Great. What other services are we offering these days? In terms of Cox Cable? Oh no, in general housing services, yeah. See, second on the list is this, no. We know a little bit about that. Yeah, I work for them. Let's see. Resnet, like I said, we provide technical and network support for students living in our residence halls. This would include getting your devices connected to the internet, such as gaming consoles, your phone, your laptop, streaming devices, your smart assistants, like anything you need to get connected. We can try to help you as much as possible to get those connected. Our contact is on this housing page. You can find our number,<PHONE_NUMBER> extension 3. You can also contact us by email and also by creating a support ticket. Also new for this year, we actually upgraded our phone system so we can text students who need help with their devices, which is pretty cool.  But with texting, it makes direct messaging students quicker. Maybe they're in class, they can't necessarily pick the phone at the moment, but with SMS texting, we can get to students pretty conveniently. That's great. Becky has a question. She said, did you say that the PO is not part of the mailing address? Let me go back to the Cox page. So on this page, the physical address is not necessarily the mailing address. So let's say for Hots Hall, I believe they use Northwest Quads PO Boxes. There's a page on there that we're going to get to called Mail and Packages, which has all that information if you want to mail something. This is really only, that table was only for if you needed service from Cox directly, because they have their information for the physical dorms themselves, not necessarily where packages go. We will get to Mail and Packages later on in this screen. I did have a question for you about ResNet that I was curious about. That service is obviously offered in the ResNet's halls and is no cost, right? Yes. Cox is provided. Our support is provided for free. And some of the other services too are also provided for free. Back into ResNet here. Our hours of operation, it says 10 to 5 p.m. 10 a.m. to 5 p.m. on the website, but we will actually operate 8 a.m. to 7 p.m., I believe, during moving to kind of help students with the flexibility. They'll be moving in all day and 8 to 5, you know, that's like the peak hours of business, and they kind of cool down in the evening, but they still might need support getting their devices connected. So I use an Xbox at home for my gaming. Is it hard to bring like an Xbox or a PlayStation or Roku? No, no, no. All these devices they are constantly maintained by UITS, our campus network service system. But they should be easily like easy to use, easy to connect. I'll get into some of the devices a lot of students bring gaming consoles, PS4s, Xbox ones. You can use them through Wi-Fi or wire connections, and it works flawlessly most of the time, but our campus is constantly changing UITS is constantly making upgrades, but if there's any conflicts, we'll let you know and you can contact us to get any information and updates about network troubles you're having. See, we also have streaming devices, Roku's, Firesticks, Google Chromecast I believe and Apple TVs. All of those except Google Chromecast I believe are supported with Google. We're still trying to work with UITS to get that supported. But Amazon, Roku and Apple TV should work and then we have our smart assistants such as the Google Home Mini and the Amazon Alexa Echo dots. I believe the Google Home Mini works. There are some workarounds we have to do with that to get it online, but you can contact us for help if you're bringing that device here. Amazon Alexa's aren't working at the moment, but like I said we are constantly working with UITS to bring many of these devices online. And we have your typical smartphones and laptops. Those always work 100% of the time. With your laptops and your smartphones, just note that you want to connect to UARC Wi-Fi and then for any devices that stay in the residence halls such as those streaming devices, those smart assistants and gaming consoles, you'll want to connect to UARC Housing IoT Wi-Fi. We will be emailing out a quick guide to students just in case this information is kind of overloading. And we also have many other technicians on the phone ready to give you information that you need or any support that you need. Don't be like overwhelmed by all the information I'm giving you about ResNet, but feel free to contact us if you need or if you forget any of the tips we provided you today. You guys are going to keep me connected, I can tell. Yeah. Pretty much it about ResNet. Do we have any questions? We do have a mailing question, but I might save that for when we get to the mail part. Services. So next on the list we have Fixit. Fixit is a service that your students can use if they have any concerns in their dorms about their physical drawers, light bulbs, stuff like that that needs repair. This service is free of charge if it is deemed that the damage wasn't intentional. But if they find you smashed your wall or something like that on purpose they will charge you for that. So with Fixit they shouldn't smash their walls? No, I don't recommend that. It's a pro tip right there. So with Fixit, if you want to submit a request you can come to our housing.york.edu come to Services, scroll down to Fixit and click this Fixit Request tab right here. It will give you a how to and how to submit a ticket. It's pretty straightforward. What you want to do is come up to this top left and click Submit a New Work Request and then you just select your building we are in Futural Hall. Click Next and you just enter your information and then the request that you are in need of and you hit Submit and this will be submitted to our Facilities and Maintenance faculty or staff members and they will get in contact with you when to schedule an appointment and once you submit this ticket you are actually giving permission for housing staff to enter your room whether you're not there. Just a note. And I'll mention it now during the COVID times. This is a practice that we've previously done. You'll be notified before you'll be notified we'll enter with masks we'll clean everything we touch and then we'll leave a sign to let you know that we've been in there and exactly what we've done so we're not going to just come in and be in your place. This is your residence hall not and it's a private place for you. There's also a key request I believe if you've lost your key or if you've broken it you can submit a key request here. I actually think that is for staff. Oh, it's for staff. One thing I'll mention also about the fix-it is that if you want your bed lofted prior to arrival that's a place where you can do that. I would say at this point probably won't happen before you get here but we'll do it within the first week or so. So if you want your bed lofted that's a good thing to do there. Next up on the list of services we have our laundry service so this is also free of charge. Students don't have to rent their coins they can do their laundry. That's pretty neat. The laundry rooms are typically the first floor and a lot of the rooms but in maples I believe it's on the corner of each wing on each floor. There's ample laundry facilities. Yeah, and Laundry Alert is a pretty great app as Tyler was saying or if you'd like to that it will tell you which laundry devices are open which are being in use and you can even go down there and then if you want to you can go down there and put your clothing in and tell Laundry Alert and it'll tell you when they're finished. You'll get an SMS text message as well so that can be pretty helpful. Laundry Alert is available on this web page right here so you can use your computer you can see here there are 10 washes available in Adobe A and you can support by you can select your dorm if you only want to view that one and there's also an iOS and Android app available if you want to connect your phone to Laundry Alert Great And we'd recommend that you use the app the app's stronger than necessarily the browser Yes Except we have mail and packages mail and packages delivered to the dorms mail and packages delivered to the dorms Not every dorm Not every package will go to your direct dorm Sometimes they'll go to a resident hall with more flexibility in terms of their infrastructure with PO boxes and front desk staff and accessibility Yeah There's a number of halls where if you want to send something to one hall it actually will you'll pick your package up at a different hall and this information from the website right here is fantastic for knowing where you need to mail your package So we can see here for go to Founders Hall you won't receive your mail and packages at Founders you'll actually receive it at Humphreys Hall and it will tell you the information for your hall and your your coordinated mail and pick up dorm You can scroll down I believe there is a page somewhere that has the actual PO addresses here But yes on this web page you can find all the information you need about picking up mail and packages Yeah If you're looking for the addresses themselves so you can go up to the top of the web page go to halls and then go to any one individual hall and scroll down There you go You can see the mail address for picking up and dropping out packages and then the actual physical location is also listed right next to it So that's just a very important thing to note actually if you want to have package delivered to you is to make sure that you're not delivering it to the physical address just make sure it's being delivered to the the PO box the mailing address Does that answer the question that we got earlier? Not quite Well a little bit Cameron asks how will I receive packages which I think we just explained and is there a limit on how many I can receive I believe not There is no limit How many do you want? We do tens of thousands of packages I think per semester People are increasingly getting their stuff that way and so we've grown to accommodate it I believe the size of the package doesn't matter either a friend of mine actually last year ordered carports and mountain biking gear boxes that he would have to haul from the PO box back to his dorm but there's also no size limit I believe too We're prepared for larger packages It's always a question of volume so like if it's a package that can fit into one of our designated package receptacles that's ideal if it can't then one of our front desk people will be like alright it's back here and give it to you even if it's gigantic Do you have any other questions about my own packages? Just along with the my received packages question do students get an alert when they have mail? They do yes they get an email alert which explains basically the process that's defined here in general we don't need to read it to them but I would suggest that you go through there and you'll have a good understanding of the package receiving process I guess the general consensus of picking up your packages make sure you have your student ID on you so it lines up with the package name and you just sign for it and then go check it out to you I'd say the majority of issues we run into with packages is it got delivered on the weekend when can I get it and usually that would be a Monday we don't have front staff members there 24-7 professional staff in the halls but not front desk staff there all the time so just be aware that the package may show as delivered according to Amazon or USPS and you won't be able to just grab it immediately it may be an extra 24 hours as it goes through our processing Sounds good Moving on to our next service which is mental health yeah our residence halls we actually provide what they call counselor in residence I believe CIRs we go into this web page it provides you with all the information you need about mental health in our residence halls I think it's a pretty neat service we provide for our students it is free of charge correct Chris? to a certain degree yes certainly if you're having an issue of struggling with exams and stress they're there they'll listen and they will help you work through that stuff when it gets to a more advanced level as I say the service is used repeatedly and I think there are some insurance issues that can pop up but certainly initial no problem at all we want our resident students to have that access through the Pat Walker health center and through housing collaborate together a space where you can go talk about what's troubling you this is a very unique time a very unique semester coming up we anticipate that students particularly those who are transitioning from their own home environment into their first year of university life might need to avail themselves of some mental health counseling and we hope that you'll use that service yes definitely on this web page you can find contact information for different CIRs on campus I believe yes so in Reed Hall there is a counselor and there's also a counselor in Gibson Hall let me point out one thing about that is these spaces where these counselors are is very discreet it's not highly visible as to when you're visiting such a place we know that can add additional layers of stress so feel free to take advantage of it and know that it won't be a highly visible thing other services sustainability our campus is very we're very creative green there's a keyword I'm looking for proactive very proactive about being eco-friendly you'll see many recycling bins in the residence halls and they're also categorized by paper plastic aluminum cardboard I believe in the housing office and just your regular trash somewhere and also this page also tells you what exactly we recycle and what we don't recycle and the process of doing that and we recycle ton starting to move in well you'll see special designated areas to do recycling during the process because so many people are buying various different things to decorate their residence hall room and they'll have packaging and we don't want you to throw it away we'd like for you to put it in the recycling bin so that we can use it again that's important to us and we have a lot of water stations around so be sure you bring a water bottle so you don't have to use a disposable it'll also give you some tips on different sustainability living life styles in your room in your hall and just around campus it's a pretty neat page to check out if you're looking to conserve our planet save the planet and here at the bottom the university or is it Fayetteville it's a collaboration between Fayetteville and the university for the VO ride program now we do have the scooters that you've probably seen at other universities as well automated scooters but we also have this program which is you can check out a bike pretty much anywhere on campus use it for a minimal cost and then drop it off a couple months ago I got one it was one of the electric ones and it was pretty fun to ride around campus on the electric one definitely a college checklist bucket list item to do once you're on campus I think it's pretty neat it's very inexpensive too and the electric scooters are pretty fun to ride around campus they can go pretty quick so I'd be careful if you've never ridden an electric scooter before yeah maybe bring a helmet even yes for those ridesharing bikes and scooters you would just download an app specific to that company VO ride spin and there's a second scooter company as the other ones I can remember but you're better than me it's an orange or blue one I can't remember they'll know as soon as they get here they'll see it we do try to be as environmentally aware as we can be and there's an office for sustainability that also provides additional information beyond just sort of the residence hall experience as to how to be as green in this community as we possibly can be well I think that covers the main services do you have any questions about any of the services we provide here in our housing building I'll give everyone maybe some time if they wanted to submit any so let me ask you a question Tyler you're a computer sciences major what's happened like it's actually been kind of rough with COVID last semester that's when I really tackled my tougher higher level classes but fortunately the professors are very forgiving during those times and they made accommodations for students in terms of exams, quizzes, homework and helping us understand some of the content better but I love the College of Engineering if you're kind of undecided I'm a little biased but definitely go towards the College of Engineering they're wonderful staff wonderful community you'll make a lot of new friends there nice, nice well I think that's it thank you Tyler thank you for having me bye everyone


some highlights here was five five the score at the half but in the second half right away a goal for Stevenson University from Kara Yeruso gives the Mustangs the lead and then inside the eight another goal for the Mustangs free position opportunity here for Brie Halpin for St. John Fisher as they get to within one nice turn spin goal for Blick here past Goodsell the goalkeeper as Stevenson kept up the offensive pressure back the other way Goodsell with a save to the corner now back up top Mary Mark finding Koslowski inside she had three goals today for Stevenson University again Koslowski past Goodsell to the keeper's left shoulder it was a two-goal lead for the Mustangs fighting back though inside the eight one of the rare times that Halpin was able to get free and it's a one-goal one-goal game there comes a free position opportunity saved by Shikosky on the near side later on DeGirolamo inside and this was kind of the final defensive stand here for Stevenson is they were leading by one and Stevenson was able to take the ball away from St. John Fisher inside the eight and take the game away from the Cardinals 11-10 the final here Stevenson winning on their home field


So, this is where we had left off in the previous class with a something called magic angle. What is that? Once again we want to deal with it briefly because we intend to come back to the issue of polarization of fluorescence in a little more detail later on. To keep it very, very brief generally you excite using a linearly polarized light and you do that because first of all the laser that you use is usually linearly polarized. If you are talking about a Ticephal laser, Ticephal laser is very nicely linearly polarized. If you are working with diode laser of course you cannot work with diode laser for up conversion for TCSPC diode laser usually is elliptically polarized which means there is a mixture of horizontal and vertical polarizations. There you put in another polarizer and generate one kind of polarization. So, when you excite with polarized light then what happens is photo selection. Photo selection means only molecules that have a component of whose dipole moment has a component along this direction is going to get excited. We come back to this in little more detail later on but the issue is this when you excite and then when fluorescence takes place even though you excite with linearly polarized light this one the fluorescence that comes out is actually depolarized to different extent depending on your sample medium and so on and so forth. And I hope it is not very difficult to understand what these jumping targets are what it means is that generally not generally always when light polarized light is incident on a nonlinear medium then the harmonic that is generated undergoes a 90 degree shift of polarization. What you see here what you see here in the red double arrow here the polarization is in the plane of the breadboard the blue light has polarization in perpendicular direction okay. So, the problem is this you have depolarized fluorescence coming out but then depolarization can take place by many different mechanisms rotation of the fluorophore while in the excited state being a major one and that brings something like a rise time in the decay unless you are careful. So, after all when you excite the molecule has this kind of polarization when it emits it has say this kind of polarization then this state was not even there so it has grown over time after excitation that can show up as a rise time. In fact if you measure at 90 degree polarization with respect to the excitation polarization you do get a rise time distinctly. And then if you measure at parallel polarization then also you are not safe because this state the state with this kind of polarization undergoes an additional decay because this one is being formed and that decay is not the decay of the excited state that decay is just because of rotation of the molecule. So if you measure along parallel polarization then you are going to get a very fast decay. So crux of the matter is because of rotation of the molecule while in the excited state you are going to have additional fast decay or rise in your decay in your transient rise in decay sounds foolish how do we eliminate that we are going to do the math in a little more detail later on. But for now let me just tell you that there is this angle 54.7 degrees which is called a magic angle you might want to be wondering why I am saying 54.7 when the magic angle written on the slide is 35.3 to understand that do a very simple bit of math subtract 54.7 from 90 degrees what do you get you get 35.3. So 35.3 because 35.3 is what you maintain with respect to the fundamental red light. So that the angle with the blue light is 54.7 degree. What happens at this magic angle so once again skipping the math for now let me just tell you that this rotation thingy has a 3 cos square theta minus 1 term and when theta equal to 54.7 degrees 3 cos square theta minus 1 is 0. So this is the angle and that is why it is called a magic angle where the fast decay or fast rise due to rotation is not observed. So what you see in your transient is just the time evolution of the electronic excited state irrespective of orientation that is why when you record lifetime by TCSPC or by up conversion you always have to measure at magic angle otherwise you are going to get additional spurious components and rotation is only one thing if there is homo freight you are going to get a rise. So magic angle is what you have to maintain and magic angle does not mean angle between the beams it is the angle between polarization that is usually achieved by something called a Berek plate once again we will not go into that at the moment later on if there is time for discussing optics in a little more detail we will come back to that. Let us just say that Berek plate is something that rotates the polarization and you can rotate it to 35.3 degrees with respect to blue well you rotate the polarization of the blue light by 35.3 degrees so that you only look at fluorescence of this polarization magic angle to the fundamental. Next let us move on a little bit and talk about something we do not have in our lab see in the experiment that we have discussed so far you have to suppose you want to know how the fluorescence spectrum evolves with time we have had a discussion of that in the one of the previous modules already. So then you have to go wavelength by wavelength emission wavelength by emission wavelength right and every time you have to record a decay stop then go and change the angle of the SFG crystal start the experiment again so all this can be made a little simpler if you do what is called 2D up conversion 2D up conversion also comes in two different forms we are discussing this the simpler form now if there is time we will talk about the more interesting form later on but for that we will need some knowledge of nonlinear optics so we are postponing that discussion. So especially Marget Chebu is group in Switzerland what they have done is that they have attached a computer control to the some frequency generation crystal. So now remember this is only thing that one thing that changes about the some frequency generation crystal is that you have to change the angle so in this instrument first of all it is calibrated and the angle for all different wavelengths is determined that what is the angle for 600 nanometer what is the angle for 605 nanometer so everything is calibrated and fed into the computer and then the rest is simple start the instrument and say that you are going to measure at every position of the BBO crystal for a certain amount of time. Now understand what is happening first your computer sets this BBO crystal the SFG crystal at a particular angle that means your omega 2 is selected omega 1 is constant anyway there now you scan the delay so you get a transient. Next you go back and change the position of the BBO crystal so instead of omega 2 A your system is tuned for omega 2 B you record a transient once again for the same amount of time when I say same amount of time I do not mean integration time I mean total acquisition time half an hour 1 hour 20 minutes 5 minutes whatever so for every angular position of the SFG crystal you record a transient but the trick is you record the transient for a given amount of time you program it in such a way that all decays are recorded for say 5 minutes each or 20 minutes each or something all of them so now some decay will be like this some decay will be bigger depending on the emission wavelength right so now the intensities are believable since you are recorded for the same amount of time. So now you get this kind of a plot you see this is a 3D plot here it is color coded x axis is time y axis unfortunately is cut but y axis is well wave number of emission so if you take a cut along this direction what do you get if you get a horizontal cut then you are keeping the emission frequency constant and you are looking at time evolution you get the decays and that is what you are measuring actually anyway if you take a vertical cut then what do you get you get the spectrum when you take a vertical cut what am I doing this is 0 time right you go from bottom to up you get the 0 time spectrum now when you are at 0.2 picosecond you go from bottom to up you get the spectrum at 0.2 femtosecond okay so from this plot you can take this cut or this cut and get either decay at a particular emission wavelength or emission spectrum at a particular time the problem here of course is deconvolution if your pulse is not so small if it is 300 femtosecond or so then at least for the first 1 or 2 picosecond you get a spectrum that is converted alright so that is a little bit of an issue but otherwise this is a convenient way of doing it if nothing else this allows you to get the decays across the entire spectrum and after that if you are if you want to include convolution you do what we did earlier convolute well deconvolute get the lifetimes using the lifetimes and steady state spectrum to generate the time resolved emission spectrum and in fact even the setup we have or the setups that are there in different labs of India can in principle be converted into this 2D up conversion it is not such a big deal you need a lab view program which is going to drive this and we will interface with the existing program or write a lab view program for the entire thing okay the other way so if you read this paper in Anju camp published in 2006 by Marith Chaguri this is what you see but then if you read the work of Therazima and co-workers what they do is that they use a very thin some frequency generation crystal and it is such that this angle tune is not even required so there you actually record the entire spectrum in one shot you use a spectrograph CCD kind of arrangement to detect the entire spectrum at different positions of delay that is a smarter way of doing it but we would like to come back to it later on if you have gained sufficient understanding of your non-linear optics and all that. Now before concluding this discussion it is important to understand where we can make mistakes okay first mistake that can come and this is something that one needs to be very very worry about is if the gate beam is not horizontal okay let us go back to the schematic remember this decay that you are generating this map of the fluorescence decay is actually raw values of intensity it is not a relative value or anything okay and remember what we had said earlier that this intensity of some frequency is sort of a product of intensities of omega 1 and omega 2 beams. One thing that we have not brought into the discussion so far and now we should is that we now need to worry about the actual spots on the Bivio crystal of course they showing you a very enlarged picture here but let us say that this red circle is the spot of omega 1 on the Bivio crystal and let us say that this one is omega 2 okay here the way I have drawn it the special overlap is perfect right all of intensity of omega 2 is in a region where omega 1 intensity is there and of course these spots are usually if you think specially they are Gaussian which means that the intensity would be maximum in the center and fall off to the sides now let us say this is the situation okay I do not if you understood what went on I will go back let us say that this is omega 2 beam this is omega 1 beam that is coming in instead of coming horizontally let us say it comes like this okay what will happen as I change the path length as I change the path length this is what will happen it is moving like this if it is horizontal it does not matter okay let us say the pulse is here well for the sake of discussion let us say I am talking about one pulse which is here okay it does not matter moves like this if it is like this then what will happen special overlap will get worse right that is what we are shown here you start with perfect special overlap but let us say omega 1 is not coming like this it is not horizontal then as it moves the overlap will become poorer and poorer okay so effectively intensity of omega 1 does not remain constant okay and effectively always unless you start from a very bad special overlap always what will happen is that as the stage moves the special overlap will become bad it will go from bad to worse so what does that mean suppose you are recording from 0 time to some time t dash okay special overlap keeps on getting worse at every step so you can think that intensity of omega 1 is decreasing for every measure so that adds another spurious component to the decay of the some frequency intensity you are going to get always so your decay is always going to look faster than it what it should look and it is not essential that you are going to be able to resolve it it is not essential that it is very fast compared to what you are looking for it may be something that is close and that is the most dangerous situation you would not even know it what you are not going to get the correct result so it is absolutely important to ensure that what we say the stage is flat which means this omega 1 light beam is flat how do you do that and that is where the role of M3 and M4 come in all mirrors have two controls horizontal and vertical if you touch one the beam moves horizontally if you touch the other the beam moves vertically okay so what you do is by playing around with the controls of M3 and M4 you ensure that the beam is horizontal how do you ensure the beam is horizontal the crude measurement is user ruler and ensure that it is at the same height from the base plate everywhere that is what you should do first secondly what you can do is you can put an additional mirror somewhere here and take your beam to a distance and put it on a wall and then move this delay forward and backward look at the spot on the wall see if it is moving vertically or not it should not move so you should keep on playing around with M3 and M4 until for delay being here at the minimum position and here at the maximum position your spot on the wall does not move that is the best way and the most strenuous way of doing and bigger the stage you work with worse it becomes okay now let me ask a question this previous first component I am talking about does it show up for smaller times or longer times shorter times or longer times definitely longer times so it is a long component that is going to be effective if it is okay that you work within 2 picosecond if your decay gets over in 2 picosecond of course the other problem for a decay that gets over in 2 picosecond is that there will be hardly an intensity that is a different issue but suppose it gets over in 2 picosecond then even if it is a little away from the alignment it will not matter but if you have to move your delay line over a length of 15 centimeter 15 centimeter is 1 nanosecond then it is so in my opinion the best way of doing it is to put it on the wall but now with advent of technology you can do other things what you could do is remove this BBO crystal or if you are scared to remove the BBO crystal at least put a lens put a mirror here and use a webcam put this of course before putting it on the webcam if you value it put a lot of neutral density filter so that intensity is as low as possible you are working with the laser after all so just put it on a webcam look at the output good thing about this method is that if you put a spot how what is the thickness of the spot the millimeter less right about a millimeter let us say that spot if you use a webcam on your computer screen will look this big alright so you look at the spot it will look like a white spot white circular spot and move the delay line and see whether the spot is going up and down since your spot is being magnified so much there is no need to put it on the wall the reason why we put it on the wall is that remember this L equal to r theta the distance that you see if this is an arc the length of the arc is equal to radius multiplied by theta right so we need a long distance so as to have a an observable value of L it is like lamps lamp and scale arrangement galvanometers that you might have used during a BSC or something in physics labs okay but you might as well use a webcam it is not advisable to use your iPhone you can use your mobile phone actually but then we are using a laser phone camera might go bad so just exercise caution but no matter what you do you have to ensure always that the beam is horizontal and you cannot think that I saw it horizontal that it is horizontal today therefore it is going to remain horizontal one year later you do not have to be so paranoid as to check every day or once every two weeks is good practice right you have to ensure that this gate light beam is horizontal otherwise all your measurements are going to be wrong especially when you are talking about longer times okay so that is the biggest thing that can give you a wrong result non horizontal gate beam second thing is magic angle if your magic angle is not setting properly and setting the magic angle is a bit of a bother because this berik plate is a little tricky thing but you have to learn it and you have to do it because if it is not at magic angle now which component will be affected the short component has to get magic third thing is something that usually we do not have a problem with is laser stability and power generally ties up our lasers of the present generation are extremely stable in their output if you keep them on for 3 days the output does not change but if your laser is fluctuating then you actually cannot do the experiment it is very important that your laser is stable throughout the experiment because do not forget you are working with actual intensities here not relative intensities so that is it that completes our discussion of femtosecond optical gating we have talked about TCSPC already there is a go between there is something called streak camera which gives you time resolution which is better than up the better than TCSPC but not as good as up conversion it is very expensive but very convenient unfortunately we do not have one in IIT Bombay but there is one in I think now IZR Pune it used to be NCBS IZR Pune has one TIFR might have had one I am not very sure there was one in Katindor so next day what we do is we briefly talk about how streak camera works and or maybe we leave it for a little later next day let us go back a little bit to the basics there is all this while we are saying that we are going to use a laser that has 100 femtosecond pulse and so on and so forth how does one produce 100 femtosecond pulse or 6 femtosecond pulse that is what we need to learn to do that we have to go back even further to the basics it is always good to start at the very beginning so in the next module we will start talking about the absolute basics of lasers we will start with Einstein's formulation of the problem of absorption and stimulated emission and spontaneous emission and from there we will try to see what are the components required to make a laser and what kind of systems can give you lasing after that we are going to learn about what are called modes of lasers there are two kinds of modes transverse modes and longitudinal modes we will learn about the modes and then we will learn how one can lock the modes together to produce pulses so that is all theory then we are going to learn about pieces of equipment that can actually do this mode locking for us actually for femtosecond lasers you need nothing they get mode locked by themselves because of a magical phenomenon called thermal lensing curr effect but if you want picosecond pulses you have to work a little harder we will learn so you have to do what is called active mode locking we will learn active mode locking because there some devices are used which are used later on when you talk about amplified lasers so we will learn about things called mode lockers and Q switches when we are done with all this then we come back and talk about what is there inside a titanium sapphire oscillator and how do you amplify pulses then we hope to go on to optical parametric amplification okay so that is quite a bit of work cut out for us but before we do all that next step is to go to our lab and have a look at this femtosecond optical gating instrument that we have there that is what the next module will be about okay we are done for today thank you very much.


We got a large crowd over there, just stay away from the air, they all gathered up throwing projectiles. Hey, do you know, Pawn Shop 2 as well, that window was broken, 13-24, can you send that to me? The Pawn Shop 13-24, send that to me too as well. 210-236, the business that was broken into on Washington, can you send me that address too as well? In the name of the business. 1100 Washington. Good copy. Hey, send that to me too, can you take, hey, if you don't mind, because I know Captain's gonna call. Do not whatever my card. No, stay here. In Washington, send me in Washington. Get crossed so nobody else can whatever. Hey guys, great league, great league, trust me brother, trust me. I got it.  Is this no, alright, you didn't. I don't care about recording, do that. 210-236, keep an eye on those vehicles down there, we got a large crowd that's coming across the street. Keep an eye on those vehicles down there. Joe, you copy along with 222?   Is this how you buddy else is? And just bring me the keys.


Yesterday I asked you to choose a crystal. Selenite, Carnelian or Rose Quartz. If you chose Carnelian, this means you are powerful, strong and protective. But Selenite shows you to be persuasive, imaginative and dreamy.  Comment me which you chose and if it's right.


Hey guys, welcome back to our channel. My name is Andrea with Food and Mentory Adventures in Food. Our channel is all about the food. We do taste test, recipes, grocery hauls, and what's for dinner. And I am here today with a quick haul from the 99 cents only store. Now, if you're not familiar with that store, everything there, well, not everything. Most things there are 99 cents, but they do have offerings that are more than 99 cents. But everything that I picked up was 99 cents or 50 cents. So let me jump right in. Okay, so a couple of things that I got that I was super excited about are these chopped kits from Fresh Express. As you can see, there were stickers on there for 99 cents. So I got the Asian chopped salad kit, which has romaine, red and green cabbage, carrots, green onions, and a Asian sesame vinaigrette, wonton strips and sliced almonds. And then I also got a Southwest salad kit, which has, there's a glare there, red and green cabbage, romaine, carrots, green onion, and then it has a Greek yogurt jalapeno ranch dressing, Mexican blend cheeses, and yellow and green tortilla strips. And then this is a really good deal too. I got two bags of Chiquita apples slices. So I got one green and then one red, which is a great deal. I got some French vanilla coffee mate creamer for Howard for his coffee. And then I saw this Marie's caramelized onion and sesame seed dressing, and this was refrigerated. And then I also saw this Simply Limeade, which is a really good deal. It was 50 cents and they only had one, so I just grabbed one. I saw this box of Kraft pasta sides. So this would be a quick meal for us, like a meatless meal with some salads. So we'll have that one night for dinner. And then I usually get these when I go to the 99 cent store. I love these wonton strips. I use them on salads. I use them in soups when I make an Asian soup. So I love these things and I just snack on them like chips. So I got some of those. And then I got some goldfish and these are tortilla snacks. So these aren't their regular goldfish. There are stickers on the packaging and basically what it's saying is that the expiration date was too close for them to send it out to stores. So I got two bags and they were 50 cents each. And then I also got a bag of the Chestnut Minis and again, those were 50 cents each. I got two bags of turkey sausage crumbles from Jimmy Dean and we can use this for breakfast.  It's a great deal for 99 cents. And then I got some of this Reese's Dairy Whipped topping and I actually got this to top hot chocolate. I love hot chocolate and I have not tried this before and it looked really good. I picked up two frozen meals, indulgence cordon blue and that really looked good to me. There it is. And it says herb breaded white meat chicken with uncured ham over orzo and a rich Swiss cheese sauce. And then I also got a devour frozen meal and it's a bacon topped meatloaf with a smoky garlic mac and cheese. And again, these were 99 cents.  So for 99 cents again, you can't beat that. So everything that I picked up was 99 cents or less. So again, the goldfish, the chestnut cookies and the Simply Limeade were 50 cents. Everything else was only 99 cents. So you can't beat that with a stick as my mother used to say. So this is it, short and sweet. I hope you guys enjoyed this haul. If you did, please make sure to give me a thumbs up. And if you haven't subscribed to our channel, I hope that you'll do so and we'll see you guys next time.


200 million children woke up this morning as slaves. 200 million. Many of these children, like this boy who's photographed here sleeping at one of our research sites in Ghana, joined tens of millions of adults as forced laborers in the fishing industry, the global fishing industry. And the fishing industry sits at the front line of the human response to environmental change. Every day, hundreds of thousands of boats head out from ports around the world and drop their net in the water in competition for a multi-billion dollar resource, a resource that provides 13% of all jobs on our planet, also provides the primary source of animal protein for the 2 billion poorest people on our planet. But 2 thirds of global fisheries are over exploited, unsustainable. Fishers today must travel farther, spend more money, take more time to achieve the same yields they had 10 or 20 years ago. This has created an increased demand for labor without increased revenue. And that's where, sadly, children and other forced laborers come in to address that need. Human trafficking is not the only consequence of our depleted fisheries. The decline of fish has resulted in increase in fish prices, which has given great global demand for alternative sources of wild meat. Those alternative sources range from the size of crickets to elephants and everything in between, in what is now a multi-billion dollar global trade in wild meat. Our research in collaboration with more than 200 informants at Cities Around the World has tracked 300,000 of these wildlife items as they move through this dark network of a commodity chain to Cities Around the World. For example, we've tracked great apes and elephants arriving in markets in San Francisco and San Jose and on our own shores, among hundreds of other sites. This trade does not spare the iconic or endangered species in these systems and, in fact, has dramatic impacts on some of the rarest species and most charismatic species on our planet. Our own research and a focus of our work has looked at how this trade has impacted large carnivores. Why large carnivores? Because large carnivores play critical roles in ecological systems. They do this by regulating many other species through their predation and also the fear they create. So what happens when you lose large carnivores, like lions, wolves, or leopards and tigers and systems, is that you see dramatic increases in the species they once contained and regulated. And these species become pests, whether they're baboons or coyotes or raccoons or other species. For the urban dweller, for example, this woman in South Africa, the rise of baboons is more nuisance, though that's pretty terrifying, I think, over a battle over groceries. But for millions of rural inhabitants, for example, this boy sitting on a termite mound in rural Mozambique, he's been taken out of school and is sitting on this mound to prevent baboon raids from the community's maize crops. In fact, he's one of millions of children who've been pulled from school in order to guard fields from baboons. So here you have a loss of education, the primary ladder out of poverty traps for millions in these rural communities is lost because of an ecological change in the environment around them. All of that may sound like a very dark global future and a dark Californian future, because the same issues of resource scarcity, labor demand, environmental justice are occurring along our coasts, occurring in our central valley and occurring in our cities. But it doesn't have to be. Through this research, we're able to illuminate not only the social and political and other systems that impact our global environment, but very importantly through this research, we're able to understand how a changing environment impacts human society. And by doing that, we start to be able to identify levers of change. For example, we may recognize that police enforcement or other actions, maybe policy, are likely to be much less effective for getting this child slave out of a boat and into school than simply working towards more sustainable local fisheries. We may recognize that restoring large carnivores in many areas in Africa, for example, may have much more of effect in getting that kid off of the termite mound and back into school than more popular development measures like school lunch programs, which really deal with symptoms rather than causes of a lot of these societal illnesses. And so this is what we're endeavoring to do here at UC Berkeley and in our lab and many other groups, and that is identify long-term strategies for a sustainable future in California, in the world, and certainly not forgetting the millions of marginalized among us. Thank you very much. Thank you.


Cancer and sun exposure. Is there a connection? This is Dr. Ruchio, and let's discuss a recent study published elucidating some interesting facts about sun exposure, vitamin D, and cancer. Now usually when one thinks of sun exposure and cancer, they think of skin cancer. But there's far more to sun exposure than just that. Now if you may have been reading a little bit more, or following any of the epidemiological literature, you have probably heard the concept that the closer you go to the equator, where there's longer exposure to daylight, longer sunlight, stronger sunlight, and generally more exposure to sun, the incidence of certain cancer goes down. So the closer to the equator you get, the less cancer there is. And it's been theorized, this is because, or in part because of vitamin D and vitamin D's immunomodulatory effects and cancer being in part an immune dysregulation phenomenon. Well, a recent study was published that had a very interesting finding. Now the authors conclude, we found that almost all epidemiological studies suggest that chronic, not intermittent sun exposure is associated with reduced risk of certain kinds of cancer. So one of the key points they're making here is that it may not be a bad idea to go ahead and get some sun exposure. And the word chronic is the key term there. This means that you're not just getting five minutes in the sun, this means you're getting 20, 30, 40, 50 minutes in the sun on most days potentially. Okay, and I'm paraphrasing there a bit. Now, onto the findings of this study. They found that some forms of cancer were prevented because of the increased vitamin D that one experiences from sun exposure. But the interesting thing, and the noteworthy finding in this study was that some forms of cancer responded to or decreased with sun exposure irrespective of vitamin D levels. And so as you can see here in the table, vitamin D had a beneficial effect or decreased colorectal cancer and breast cancer. Now you can also see that vitamin D had no effect, but sun exposure decreased prostate cancer and non-Hodgkin's lymphoma. So when they looked at these four cancers in the study, they found that the prostate cancer and the non-Hodgkin's lymphoma both decreased because of sun exposure and there was no correlation to vitamin D levels. So what this tells us is there are other beneficial anti-cancer properties conferred by the sun outside of just the vitamin D. So what's your take home? Get out in the sun. Get reasonable and responsible sun exposure. One of the things that's recommended in the research is what's called the minimal erythema dose, which means get enough sun to cause a slight pigment change in your skin, a slight pinkening of the skin or a slight tanning of the skin, and that should be sufficient. You certainly never want to burn, but I have to say after looking at numerous studies on this topic, the touted idea that we should live like vampires and slather on the SPF 1000 and cover up all of our skin from the sun is a recommendation that may not be that intelligent. Now to briefly speak to the point of skin cancer going into all the details of that is slightly beyond the scope of this video, but two things. One, we know that yes, if you burn, you will increase your risk of certain types of skin cancer. So you never ever want to burn. But we also know something, and this was best articulated by the PhD researcher named Tony Peroni, who said, when we want to induce skin cancer in lab rats, we do not expose them to UVA UVB radiation. We put chemicals on their skin. And if you look at many of the skin products out there today, they have either potential carcinogens or more strongly associated some that are called probable carcinogens. So we have that factor on the table as well as just the general environmental toxicity that has been known to promote the process of oncogenesis or cancer promotion. So it may not be the best recommendation to avoid the sun because of skin cancer, because if you get responsible exposure to the sun and you avoid putting carcinogens or potential or probable carcinogens on your skin, you should have a very low risk of developing skin cancer. So again, your take home is get some time in the sun. Enjoy yourself a little bit. This is Dr. Ruscio, and I hope you find this information helpful. Thanks.