So you need to raise your hands and I'm randomly going to ask somebody so what it means is If you have a Class and you want to object of a class and you want to downcast it to a subclass What is the operator you are going to use? Yeah, that's correct Need a browser Yeah So the answer is basically you use you know whatever object it is, right? object one As a type, you know, whatever the subclass name You can use optional or I think not even if you don't use You just use age We need optional Which if you put optional is basically answers that if this fails then this Object is nil and which you can handle it on This is a dictionary declaration of a specific type And you need to support something here What is the thing that you need to put in the declaration? You need to raise hands That's that's kind of disqualification Okay, which is the keyword used to observe property changes on a property Just after it is set to a new value, which is really I'm not going to ask to you Which is basically a new feature in swipe in objective see what you had is Observers or delegates on on the view controller level is just like you had View did load view will disappear. You did disappear. Well, Swift has property observers on on the property label And you can do certain stuff When the value is set to something Let's say you have a label and once you assign certain things to the label You want to change the color of the label or you want to assign a new property to the font you can use these property observers So, but what is the keyword? You know That's correct again Unfortunately, I have only 10% so you can't really Now this is not just for one book you can you can buy any books from the store, so And you I'm going to leave it here just in case anyone There's something missing in this in this code. Yeah, that's great Because when you're overriding a function, right? You're basically need to ensure that the superclass method gets executed properly so you need something like Super That's it for tonight. Thank you I'm going to ask more difficult questions coming But as I mean Talking about the sweep study group, it's going to start from Starting next month and I'll send out the details. I'll probably not use the meetup group to announce it So because then it's going to spam everyone who are not interested in the study group, for example So I'm going to use the Facebook group. If you haven't Just join iOS steps out on Facebook and I will I will announce about the study group This is probably still going to happen here because it's easier for me to organize here And then if it's here, then I can probably try to get sponsorship for food as well I can't promise that at the moment if we do it very regularly I'm also But feel free to hang around for quite a bit. I think it's mine You can wrap up around 9 30 you want to talk to each other Then just feel free to hang around and talk to each other. Thank you all for coming tonight. Thanks


Okay, thank you. Many thanks to the organizers for this opportunity. This is based on this paper that we wrote with Rachel at Columbia. Okay, so the subject of my talk is partially mass risk gravity, which I'm assuming not everyone here or most people here are not familiar with. So I'm planning to spend a good fraction of my talk simply introducing the subject, okay? Okay, so my starting point is a massive spin-to-fill on a constant curvature background. So imagine splitting the metric into a constant curvature background, which is either the seater or anti-the seater plus a fluctuation, which is our graviton, okay? Okay, so as we learn on Monday, the free theory is described by the third spowly action. The only new thing here is that instead of partial derivatives, we have covariant derivatives defined with respect to our background geometry. And we also have a curvature term that comes from linearizing the cosmological constant term in the Einstein-Hilbert action, okay? So this R bar is a constant. It's just the richest scalar of our background space, okay? And let me remind you that we also have a mass term now for a massive graviton, which is given by this expression here, with m being the mass of the graviton. Okay, so we also learned about this Stuckelberg method, which is a nice way to study the degrees of freedom of our theory and also their stability. In particular, for gravity, we take our tensor field and replace it with this expression. So we introduce a new vector field and also a new scalar field. And the only new thing here is that we should use covariant derivatives rather than partial derivatives because our background is now curved, okay? So Rachel showed that there exists this relativistic limit which formally amounts to taking the mass of the graviton to zero. And in this limit, these three fields become the independent helicities of our massive graviton. So in particular, the tensor field becomes the helicities plus and minus two. The vector field becomes the helicities plus and minus one. And the scalar is just the longitudinal mode, the helicity zero, okay? So for generic values of the rigid scalar of the background and the graviton mass, these helicities are all physical, okay? They are all propagating degrees of freedom. And therefore, if you do the math, you find that the theory has five degrees of freedom as you would expect for a massive graviton, okay? And the theory is massive gravity. Okay, so this is, let me emphasize, this is for generic values of curvature and mass of the graviton. So what about the stability? So this is like a plot in the theory space of massive gravity, so to speak. So the horizontal axis is the mass of the graviton and the vertical axis is the curvature of the background. So when you are in the upper half plane, this is the seater with positive curvature and in the lower half plane is anti-the seater with negative curvature. So it can be shown that the helicity plus and minus one mode of the graviton is stable provided that the mass of the graviton squared is positive. So that rules out this whole region on the left, okay? So yeah, so in this region, the helicity one is unstable. It's a ghost and therefore you can rule out that region. The helicity zero is stable provided that the mass squared of the graviton satisfies this inequality. This is called the Higuchi bound and therefore on this plot, this region here in blue is ruled out. So in this region, the helicity zero is unstable. It's a ghost, okay? So that gives you this wide region here as the space of theories which are stable, okay? So note that these bounds are strict. So this is strictly greater, strictly greater, but you may ask what happens when we saturate the bounds and it turns out interesting things happen because we get gauge symmetries when we hit the bounds. So in particular, when this is well known, when the mass of the graviton is zero, you know what you get, you get GR. That's the theory of a mass less graviton which has this diffeomorphism symmetry, linearized diffeomorphism symmetry because so far I'm dealing only with free theories. And this theory has two degrees of freedom rather than five. So when you are on this line here, M equals zero line, you're five degrees of freedom. Some of them become unphysical, they become pure gauge and you end up with two physical degrees of freedom corresponding to a mass less graviton. Perhaps more interesting is when you saturate the Higuchi bound when M squared equals one sixth of the curvature radius. In this case, this corresponds to this line here which node is in the sitter half of our theory space and this corresponds to this partially mass less theory of gravity and this has this curious gauge symmetry. It's a scalar gauge symmetry because the gauge parameter in this case is a scalar and it involves two derivatives in this case, okay? So it's kind of curious in the sense that you have a massive field with a gauge symmetry living in the sitter, okay? This is partially mass less gravity. Okay, so in a nutshell, the main properties of this theory, as I just said, the graviton has a mass that is given by this value. It's a fraction, a specific fraction of the curvature of the Ritchie scalar of the background which can also be written in terms of the cosmological constant like so. The theory has a scalar gauge symmetry, as I just said, which has two derivatives and this gauge symmetry removes the Helicity zero mode of the graviton. So this is a spin two field that has four degrees of freedom, has the Helicity plus minus one and plus minus two, but not the longitudinal mode, okay? So those were the main basic aspects of this theory, but there are also some interesting phenomenological consequences. The first one, probably the most interesting one is the cosmological constant problem. So I just told you that the cosmological constant is related to the graviton mass by this equation. So they are related by order one numerical coefficient and therefore having a small cosmological constant is equivalent to having a small graviton mass. But this is great because having a small graviton mass is technically natural. The reason being that when the mass of the graviton is exactly zero, you know that you recover the diffeomorphism symmetry of GR. So it's kind of when the mass of the graviton is zero, you have more symmetry so to speak and that implies that a small m square is technically natural. It does not receive large quantum corrections. So if you start with a small mass, then you know that that's going to be under control under quantum corrections. That's what we mean by technically natural, okay? A second interesting consequence is the fifth force problem. Rachel talked about this on Monday. This is the BDBZ discontinuity. And so as you learn, in massive gravity, the helicity is zero mode. It remains coupled at short distances. It remains coupled to matter at short distances. So the Lagrangian looks roughly like this. This is what you would expect to see at short distances. We would expect to have GR at short distances. However, we have also this coupling between the longitudinal mode and the trace of the stress energy tensor. And this gives rise to a fifth force, which we don't observe, of course. As we learn also, this is solving nonlinear massive gravity by the Weinstein mechanism, which consists of the sort of killing of these longitudinal mode at short distances by means of the nonlinearities of this field. So around a source, say a star of mass m, the profile of the field looks roughly like this. It goes like one over r at large distances, but at short distances, it goes to zero as some power. So this renders the field and the corresponding force unobservable. So the Weinstein mechanism is great because it solves this fifth force problem. However, they're surprised to pay, which is generically perturbations in this nonlinear region are superluminal. This is not really a theorem, but it's kind of a very generic property of this Weinstein mechanism. But the good thing of portioning massless gravity is that we never have to worry about this because we just don't have this longitudinal mode. So that's great. We never have to really worry about this issue of having superluminality in the nonlinear regime. Okay. Let me skip the details here. There are also some nice analogies with electromagnetism. So for example, you can write the partially massless action like in Maxwell-like form, F squared. So if you define this tensor F as the anti-symmetric, the derivative of H, then the action can be written as F squared, roughly speaking. And this F is an invariant field strength, just like the F mu nu of electromagnetism. It is invariant under the gauge symmetry of partially massless. And there's also a duality invariance. If you go to Hamiltonian formalism, you can define as sort of EMB fields in terms of which the action has these duality invariance pretty much like in EMM. Okay. So, so far I've been telling you about the free theory. So the action that I wrote down was just the quadratic action. But the question, the obvious question is whether there is a nonlinear theory of partially massless gravity. That is, can we add to our quadratic action that we know? Can we add higher order interactions to this field? Well, this is a gauge symmetry. So we should also expect to have nonlinear corrections to our gauge symmetry. Like it happens in young males, for example. So this delta zero H is the gauge symmetry that we know. The one that corresponds to the quadratic action. But we in principle should expect to have higher order corrections to this symmetry. Okay. So know that this lowest order symmetry does not involve any powers of H on the right hand side. But in principle, we could have a gauge symmetry that involves the field itself, like in young males, for example, or GR. Okay. So unfortunately, so far we only have negative results. So first it was shown that this partially, this nonlinear theory of partially massless gravity cannot belong to the DRGT class of ghost free massive gravity. That's one thing. More generally, even if you don't worry about ghosts, it was shown that you can make a very generic, very general answer. So assume that the kinetic Lagrangian is a Hilbert and add just any potential that you want. And it was shown that a theory of this class cannot have this partially massless symmetry at nonlinear order. And even more generally, it was shown that even if you relax the assumption about the kinetic terms, so the only constraint being now that the action has two derivatives, it was shown that partially massless gravity cannot have this form at the nonlinear order. Okay. So these are very general no-go results if you think about it because the only assumption here is that the action has at most two derivatives. So imagine writing anything you want with up to two derivatives. The claim is that that's not going to have the partially massless symmetry at nonlinear order. Okay. So the method here, the method we used to prove this is based on this closure condition on gauge symmetries, which is kind of a nice method because it doesn't make any assumption about the form of the action. That's why it's so general in a sense. It only relies on the form of the symmetry. So just to explain the method quickly, let me do the spin one example. So the starting point here is the Maxwell action, which you know has this usual gauge symmetry. And we look for nonlinear extensions of this symmetry. So we write generically, we can write a nonlinear gauge symmetry in this way where this beta and alpha are the functions that we want to determine. So beta is some arbitrary function of powers of the field and alpha likewise involves one derivative and powers of the field, like so. And our goal is to determine this symmetry. Okay. And here the method is based on this closure condition that the commutator of two gauge transformations has to be itself a gauge transformation. That's kind of an integrability condition for a gauge symmetry. And it follows from Frobeni's theorem. Okay. So the goal is to solve this equation for our unknown functions, alpha and beta. And skipping all the algebra, the result turns out to be just the trivial one. Beta has to be just the Kronecker delta and alpha has to be zero. And as a result, the most general gauge symmetry for a single spin one field turns out to be just the usual Maxwell symmetry, this one. And as a consequence, this tells you that the most general low energy action that you can write down for a spin one field is just a Maxwell action. There's nothing else you can write down. Okay. And this all follows from this closure condition on the gauge symmetry. You can play the same game with multiple spin one fields. Let me skip the details here. It turns out that you can derive young mills using this method. Right, so this is the result. If you apply the closure condition to multiple spin ones, you find the young mills gauge symmetry. And therefore, as a result, you get that at low energies, the action has to be the young mills theory. A third example is the spin two, a mass of the spin two in this case, which has linearized the filmorphisms as a symmetry. And playing the same game, you turn the crank, turns out that you can derive GR. So in this case, you find that the most general gauge symmetry for a mass of spin two field turns out to be non-linear diffeomorphisms. So you can derive GR using this method, starting from the free action of a spin two field. And this is kind of nice because in our starting point, in the linearized action, there's no reference to manifolds and geometry. So it's kind of similar to the desert construction that Rachel described on Monday, in which this geometric picture of GR sort of emerges as a consequence, rather than as an assumption, okay? So this is the result for a mass of spin two case. And again, at low energies, this symmetry implies that the action has to be Einstein-Hilbert. So you can derive Maxwell theory, you can derive young mills, you can derive GR using this method of the closure condition. Okay, so just to finish here, what we did with Rachel was to apply this closure condition to partially massless. So our starting point is the quadratic partially massless action, which has this lowest order symmetry. And in this case, the general form of the non-linear symmetry now involves three unknown functions because it has two derivatives. So it's a bit more complicated. But nevertheless, you turn the crank and you can show that the general result turns out to be this for these unknown functions B, D and C. And let me remind you this F tensor is the Maxwell-like tensor for partially massless, this anti-symmetric derivative. So this is the punchline. The most general gauge symmetry for a partially massless spin two turns out to be this. This is the lowest order one corresponding to the quadratic action. And we found this unique non-linear extension that involves this tensor F. So this is quadratic in the fields. And let me point out this, just to remind you this phi is the gauge function. It's a scalar. And this gamma is just an arbitrary constant. Okay, so this was the symmetry. What about the action? So I've been selling you this method because you don't make any assumptions about the form of the action. So it's kind of super general. You only rely on the symmetries and you don't make any assumptions about the action. But at the end of the day, you obviously want the action, right? So to find the action, what you can use is the net identity. So let me remind you that if you have a gauge symmetry, there exists a corresponding net identity, which in GR, this is just the Bianca identity. So if you have the filmorphisms, you know that you can derive the Bianca identity like this. And in general, net identities are always of the form differential operator hitting the equation of motion equals zero. This is always the case. For partially massless, the net identity gives you this mess here. Again, this F is this anti-symmetric combination and E3 is the cubic part of the equation of motion. This is what we are after. Remember, we are trying to find nonlinear extensions for partially massless gravity. We have the quadratic equation of motion that's known and we're trying to find nonlinear interactions. So this is what we are after. And the result turns out to be there's no solution. If you stick to actions with two derivatives, it turns out that there's no solution for the equation of motion at cubic order. So that's our no-go result. Yeah, bummer. Okay, just to wrap up in one minute. So I told you about partially massless gravity. This is a theory of a massive graviton that lives on the cedar and enjoys a gauge symmetry, a scalar gauge symmetry. I told you about the free theory because that's the only thing that is known so far. The obvious question is whether there is an interacting theory and I hope I convinced you that this is a well-motivated question. But we have these very general no-go results that any nonlinear extensions must necessarily have more than two derivatives. So some future prospects. Well, one obvious one that follows from this is that whether there could be higher order derivatives interactions. Second, you could consider coupling two other fields. So far, I only consider a single partially massless field. But you can consider, you can imagine coupling this field to say a massless graviton or two other partially massless fields and so on. And finally, I didn't talk about this, but it turns out that these partially massless fields exist for any higher spin, for any spin greater or equal than two. So you can imagine playing this same game for higher spin fields and see whether you can get interactions for these fields. That's it, thank you.


Hey man, so keep your place in Joshua chapter 10. We're going to start out there this evening, but just a little bit of a pretext before we begin this evening. So this sermon this evening is going to be the second in a sermon series that's going to be ongoing, but this will be the second. I'm calling this series, How Stuff Works, I guess, is what we'll put it. The category we'll put it on our YouTube channel or whatever. The first in this series was, if you remember, the sermon called How the Universe Works. And if you remember that sermon, the point of these sermons, you say, what's the point of these types of sermons? The point of these sermons is to show you that we're living in a day where people will say, oh, religion says this, and then science says this. And they're two different things. The point of these sermons is to show you that the Bible is a very scientific book. As a matter of fact, it is the scientific book. And as a matter of fact, it used to be, and I'm going to show you a little bit more this evening, it used to be that the people that did understand the Bible were much better at applying science and figuring out the mysteries of the greatest scientist that the universe has ever known, which is God, who made all these rules and made these universes. So I would invite you, especially those watching online, if you haven't watched How the Universe Works, watch that sermon. It'll help you understand some of the things that we're going to talk about this evening. We're going to dive down a rabbit hole this evening.  But let's start out in Joshua chapter 10. But the title of the sermon this evening on that pretext and on that introduction is How Time Works. I'm going to tell you how time works this evening. Let's look down at Joshua chapter 10. And I want to just kind of get through what's happening in the story. We'll preach through Joshua chapter 10 verse by verse next week. But basically in Joshua chapter 10 in the first four verses, we have these five kings getting together and they band together as we saw that kings were starting to do in Joshua chapter nine. And they decide that we probably can't beat Joshua and the children of Israel. So let's go beat up on the Gideonites who've made peace with Joshua. We can't beat them, but let's try to beat their friends. So they go and they attack the Gideonites and look at verse number five. Therefore the five kings of the Amorites, the king of Jerusalem, king of Hebron, the king of Jarmoth, the king of Lekesh, the king of Eglon gathered themselves together and went up they and all their hosts, their armies, and they encamp before Gideon and made war against it. So there's this huge conglomeration of these five nations that comes up against Gideon. So I mean, when you look at it from the perspective of the Israelites coming in to conquer these nations, you can kind of see that there's an opportunity here. These kings are all together and they're now coming all at once. Before it was just one city, after another city, here you have these five kings and their armies banding together. And you'll see that God gets a little bit more invested in this opportunity that the Israelites have. So the men of Gideon sent unto Joshua to the camp to Gilgal saying, slak not thy hand from thy servants, come up to us quickly and save us. So they send to Joshua, verse seven. So Joshua ascended from Gilgal, he and all the people of war with him and all the mighty men of Valor. So all these five kings come at once, this huge opportunity, and here comes Joshua to meet them, to defend Gideon. But more importantly, to just defeat these five kings in one shot. Look at verse number eight. And the Lord sent unto Joshua, fear them not, for I have delivered them into thine hand, there shall not a man of them stand before thee.  I mean, that's some confidence right there.  Joshua therefore came unto them suddenly and went up from Gilgal all night. And the Lord discomfited them before Israel and slew them with a great slaughter at Gibeon and chased them all the way to goeth up to Beth Horan and smote them to Azikah and unto Makeda. And it came to pass as they fled from before Israel and they were going down to Beth Horan that the Lord cast down, now it's interesting because in verse number eight he said, there shall not a man stand of them before thee. He's like, nobody's gonna get away. And then look what God does in verse number 11, they're getting away, they're fleeing away and the Lord cast down great stones from heaven upon them unto Azikah and they died. And there were more which died, now let's see who did a better job in the battle here. There were more which died with hailstones than they whom the children of Israel slew with the sword. So look, here they're at in this battle and these kings, they're all retreating. Joshua has won the battle and God creates this huge hailstorm that just kills all the rest of them and it was the majority of these armies that God killed with the hail. And he killed more of them with the hail than Joshua slew with the sword because they immediately ran away. Now look at verse number 12. Then spake Joshua to the Lord in the day when the Lord delivered up the Amorites before the children of Israel. And he said in the sight of Israel, listen to this, listen to the confidence of Joshua here. He's in this battle and he says to the children of Israel, he says to God in front of the children of Israel, sons stand thou still upon Gideon and thou moon in the valley of Agilon and the sun stood still and the moon stayed until the people had avenged themselves upon their enemies. Is it not written in the book of Jasher? So the sun stood still in the midst of heaven and hastened not to go down about a whole day. And there was no day like that before it or after it that the Lord harkened unto the voice of a man for the Lord fought for Israel. So here's something like just extraordinary happens. Joshua asked God to stop the sun and the moon. So the sun and the moon, they go together if you've ever paid attention. But the moon goes down, the sun comes up and then it reverses itself, right? But God literally makes them both stand still for the span of 24 hours, it says. So Joshua can have more time to defeat, he can have more daylight. He can have more light to defeat this enemy completely. So God stops the clock is what God did here. So that brings us to the topic of our sermon and we're gonna leave Joshua chapter 10 right here but that brings us to the topic of our sermon this evening which is how time works. We see this extraordinary event happen in Joshua chapter 10 where God, it's the only time in the Bible where God literally stops the sun for 24 hours. God's done something similar and we'll talk about that a little bit later but this was the most significant event as far as God's stopping his clock in the Bible. So let's look at how time works because guess what? The Bible tells us how time works. The Bible tells us everything that we need to know about time and the Bible tells us what it is, who it belongs to, what it's for, the whole thing, all the answers and that's what we're gonna talk about this evening. And then we'll look at what man thinks about time and we'll look at what the consequences are that man thinks that about time. So let's look first at what is time? If we wanna know how something works, we need to know what it is.  You know, what's the point of this thing? What is time? Let's start at the beginning. Go to Genesis chapter one. Genesis chapter one. Go to Genesis chapter one in verse number 14. God, of course, is speaking the entire universe, everything that we know. He's speaking the creation into existence. In Genesis chapter one, look at verse number 14. Super important verse in the Bible right here. And God said, let there be lights in the firmament of heaven. To divide the day from the night and then let them be for signs and for seasons and for days and for years. Notice the purpose given here for the solar system, the universes, is what God is talking about here. Men, look, men have wasted their whole lives barking up the wrong trees on what the point of the universe and the solar systems and all these stars and planets, what the point of them is for. But look, I'm gonna show you tonight that they should have just started with the Bible and they would have known. Look, the Bible tells us here that there's three specific reasons. Four, you know, the sun, the moon, the planets. They have three purposes. The first one is for signs. We've talked about this. God is going to use the solar system and the stars, the moon, the sun, the planets as signs to show us what's going to happen for the things that he calls out in the word of God. The second thing is for the seasons. It's for the seasons. It's so we can, I don't know, live. It's so we can live, we can survive. Things can grow. So there's a rainy season and a winter and moisture can store itself up in the mountains and come down for the other seasons. So the water cycle, we've talked about this as well. So the water can refresh itself for us every single year. So we see it's for signs. It's for seasons. And then, look at number three. This is the important one that we're gonna talk about. They're all important, but this is the one that we're gonna talk about this evening. And for days and for years, he says. Turn to Genesis chapter six in verse number three. You know what that means? And for days and for years, you know what that means? Time. It means time. Turn to Genesis chapter six and look at verse number three. Look what the Bible says. And the Lord said, my spirit shall not always strive with man for that he also is flesh yet his days shall be 120 years. See how there's days and years? This is God using. So God, look, God created the solar system, the planets, the stars, the entire universe as a clock. For time keeping. Did you know, you're like, what? You're like, what? Did you know the most advanced clock that we have today? Think of all the things we invented today. The atomic clock. Do you know that the atomic clock today that is invented, the cesium clock that literally moves on the vibrations of an atom has to be periodically adjusted for solar time. Solar time, you know what solar time means? You'll hear this scientific term, solar time. Solar time, you know what that means? God's time. That means it needs to be adjusted slightly every single year to match God's clock. That's what it means. The definition of a day. You know who that belongs to? It belongs to God. The definition of a day. Look, the rotation of the earth and the sun around each other, you know, every 24 hours. You know, the spin of the earth that you were taught in school, if you were ever taught that. Look, that is a day. That's what a day is. That's God's clock. The orbits of the planets. You know, the sun and the moon and the earth and all these orbits, as they go around each other, that's a year. That's the seasons. This is solar time. Now that has already been set in motion. It's interesting how all this matches the Bible when you talk about a day and times. When you talk about a year and seasons, it all exactly matches in the Bible. The point I'm trying to make is, is that our current most technological basis for measuring time is based on God's clock. It's that simple. You say, God's clock? You're skeptical. You don't believe the Bible. Somebody watching. You say, God's clock? Well, I mean, has anyone else stopped it before? Has anyone else stopped the clock besides God? Look, God stopped the clock here in Joshua chapter 10, but he's done it before. Turn to 2 Kings chapter 20. Turn to 2 Kings chapter 20. He did it again in the Bible. Look at 2 Kings chapter 20. As Hezekiah was sick and Hezekiah was praying to God that he would not die, he was asked for a sign and Isaiah said that God would show him a sign. And here's the sign that he was to get. Look at 2 Kings chapter 20. Look at verse number nine. And Isaiah said, this sign shall thou have of the Lord, that the Lord will do the thing that he has spoken, meaning heal you, shall the shadow go forward 10 degrees or go back 10 degrees? Meaning the shadow. If you stand in one place during the day, your shadow will move as the sun moves across the sky. Look, he's saying should it go forward or just go backwards? And Hezekiah answered, it's a light thing for the shadow to go down 10 degrees. He's like, it always moves this way. He's like, let the shadow return backward 10 degrees. And Isaiah, the prophet cried unto the Lord and he brought the shadow 10 degrees backward by which it had gone down in the dial of Ahas. So where did the shadow come from? So what happened if his shadow moved backwards? If your shadow normally would go like this as the sun rises in the east and sets in the west and your shadow typically would move this way and your shadow moves the other way, God moved the sun. God moved the clock. God took the clock and he backed it up 10 degrees in this story. God controls his clock. God controls his clock. Now look, did God in Joshua chapter 10 and even in Hezekiah chapter, in 2 Kings chapter 20, did God stop time itself?  But did everybody in Joshua chapter 10, when God set the, did everyone freeze? Were they all like, and then Joshua just went around like, no, God just gave him, he stopped the solar system so he could have more daylight. Same thing here, Hezekiah didn't all of a sudden start going like, you know, I mean, look, that's science fiction stuff. God simply stopped his mechanical clock of the universe here, okay? He simply stopped the solar system for a practical reason in Joshua chapter 10. But look, all the gears are connected, folks. The clock is his, is the point I'm trying to make, okay? But what about time? What about time? God didn't stop actual time, right? Who controls time? Let's look at that now. The Bible actually tells us that too. Who controls actual time? So we see that there's a big physical mechanical clock of the solar system that God has put in place. Turn to Jeremiah chapter eight. Let's look at who controls actual time itself because the Bible talks a lot about this. Who controls it? Hint, it's not or ever going to be us. I hate to give it away, but it's not gonna be us. Look, we're gonna look and I'm gonna prove to you that we will never be able to control time. I'm gonna prove to you from the Bible and I'm also gonna prove to you from the world, from the things that we can see in the world. You're like, whoa, because if somebody doesn't believe the Bible and they listen to a message like this, look, I'll prove it to you from just what we see in the world that we will never control time. Joshua or Jeremiah chapter eight. Look at Jeremiah chapter eight and look at verse number seven. We're gonna do some, we're gonna do a lot of flipping to Bible here. There's a lot of Bible on time. Look at Jeremiah eight and verse number seven. The Bible says, yay.  But my people know not the judgment of the Lord. Look, here's what God is saying here. Turn to Psalm chapter 31 while I explain this. Here's what God is saying about times. He's saying, look, the birds know where they're supposed to go at what time. He's like, the birds know when to go south and when to go this way and when to go that way. You know, birds migrate.  I've thought about that my whole life. They just all of a sudden, they just, I mean, you'll wake up one morning. It'll be duck season. It'll be crazy duck town in North Dakota. In the next day, they're all gone. Just like that. And we're like, guess duck season's over. Because they just know, they all go together. They all know when to go. And God's saying here, the birds know. He's like, you have no idea though. It's like, you don't know when my judgment comes. We'll get to that in a minute. So basically, God is saying here that my judgment is coming at a certain what? A certain time. He's like, you're not gonna know when it is. It's like, the birds know where to go. At what time to go? He's like, you're not gonna know when my judgment comes. Turn to Psalm chapter 31. And you know what he's saying in the context? What's he talking about? Who are we talking about here? We're talking about Jeremiah. He's like, get right. Get right. Get right. He's like, you're gonna be invaded.  Judgment's coming. Judgment's coming. He's like, look, if you knew that it was gonna, if you knew judgment was gonna be in three years, you think you'd be getting right today. He's like, you don't know what time judgment's coming. It could be coming now. He's like, get right. God wants it that way on purpose. And that's what Jeremiah was telling the people. Look at Psalm 31, verse 15. My times are in thy hand. Deliver me from the hand of mine enemies and from them that persecute me. Turn to Acts chapter one.  God's hand. He's saying, my days and my years, the time that I have on this earth is in God's hands. I don't even know many people out there soul winning that you could actually bring that up to that would argue with that.  Because most people would say, most people when you're soul winning at the door and you say, look, do you know if you're gonna live another day? They're like, no. Like you could die in five minutes, right? Yes, the youngest kid will tell you that. A teenager will tell you that at the door. Yet we're just dumb. We'll get to that in a minute. My times, your hand, God. God controls it. Look at Acts chapter one, verse number seven. And he said unto them, it is not for you. Underline that. Underline those words. It is not for you to know the times or the seasons. Well, who's it to know then? It's not for me. It was just nobody know. Just keep reading. It is not for you to know the times or the seasons. See at times, seasons. See how it's all just perfectly, it just matches up everything. For which the Father have put in his own power. Look, God knows the time. God knows the seasons. Not you. Look, the world itself is on a countdown. That's what the Bible is saying. The world itself is on a countdown. Turn to James chapter four. Your life is on a countdown. Your life is on a countdown. And guess what? You don't know when zero's coming. And God wants it to be that way. He doesn't want you to know that. Look at James chapter four and verse 14. James chapter four and verse 14. Whereas you know not what shall be on the morrow. For what is your life? It is even a vapor that appeareth. What do you mean it's a vapor? What does that even mean? It means that it appeareth for a little time. And then vanisheth away.  It says you don't know. Look, you don't know. God doesn't want you to know. If God wanted you to know, he would let you know.  He'd have told you in his word. But he doesn't want you to know. Look at second, let me read you for Job chapter seven and verse number seven. Oh, remember that my life is a wind. My, even Job knew. He's like, my life is like a wind. I don't know when it's gonna start and stop. Second Samuel chapter 14, look at verse 14. For we must needs die. And now this is really interesting. I don't know how many times you've read this verse, but it's super interesting when you think about it. We must needs die. It's like, we're gonna die.  And it has water spilt on the ground. But look at the next words, which cannot be gathered up again. You know what that says? You know what that says? It means that time when it goes by, it's like, you can't get that back. You can't gather that back up again. You know, look, God is using time in the Bible. He doesn't allow us to control it. He says it's in my hand. We don't know when the times are gonna come. We don't know when his judgment is coming. He uses time to motivate us. Is what God is doing here. It can't be, look, it can't be stopped. It can't be slowed down. And it can't be gotten back. Look, there's no time travel. We're never gonna be able to travel back in the past or the Bible's not correct.  Look, the world itself turned to Matthew chapter 24. The world itself is on a countdown. God has put this whole thing together. He's got this massive physical clock running. He stopped it a couple times for specific reasons for a few hours. But he's got this massive physical clock in motion and it is literally counting down his creation. Think about that.  Just from a biblical perspective.  He controls it, we don't. We're to do what we can with whatever he gives us in that category. It certainly is his, not ours. Look at Matthew chapter 24. And not only do we have a countdown that the world is on a countdown but he gives us clues so we can watch that countdown. Look at Matthew 24 in verse number seven. Remember the sermon on clues and milestones? He gives us clues. Look at Matthew chapter four in verse number seven. For nation shall rise against nation. Kingdom against kingdom. And there shall be famines, pestilences and earthquakes in diverse places. These are all, all these are the beginning of sorrows. Look, these are clues. These are clues that we should be watching for that will tell us where we're at on the clock. And look, that clues are just, that's what they are. They're clues. There's nothing that you can really just say, oh, there's a pestilence. This is the end times. It's just a clue. It's something that's put there so we can notice things. Earthquakes, famines, pestilences, wars. There's always wars, but they're clues. They're clues for us to notice, folks. Now there's milestones, right? There's milestones that we talked about. Milestones like the Antichrist. That's a milestone. We hit that one. Some guy stands in a newly built temple and declares himself to be God. Okay, milestone. We're marking that one down. There's the mark of the beast. There's tribulation. I mean, that could even kind of be a clue, but then there's the great tribulation. I mean, these are milestones, but they're milestones and clues to show us where we're at, what? That to show us where we're at on the timeline of the countdown. Does that make sense? It's a timeline. And time itself and this timeline is his. It's his. Tick, tick, tick. It's going by and we cannot stop it, slow it or reverse it. You follow me so far? Enter Albert Einstein. 1905. In 1905, Albert Einstein publishes the theory of special relativity in which time is variable. He makes time variable. He makes time something that we can control by how fast we accelerate a vehicle, how fast we can travel. All these things, you know, by gravity itself is time is a variable. And I'm not gonna look, I don't have the time or the scope we can talk about it after to get into the actual theory itself, but time, he makes a variable. He spurred this idea that we can one day and we'll be able to control, manipulate or possibly even travel through time. And look, many science fiction books, movies, propaganda, whatever that have been after this point have been based on what Albert Einstein postulated in 1905. Now I'm gonna show you, I'm gonna show you this evening how I know the theory of special relativity is false and general relativity that came later. That one's false too. I'm gonna show you from the Bible and I'm also gonna show you from the physical world.  Yeah, and I'm glad to stand behind it. I've looked into this a lot in the last 20 years. I'm gonna show you how stupid science today has gotten and I'm gonna show you, when I quote things, I'm gonna quote things from liberal websites and liberal propaganda that love Albert Einstein. Okay, here's from Wikipedia. On the theoretical time machine, a theoretical time machine that could work based on Albert Einstein's theory in 1905. Here's what Wikipedia says, okay? If you had a spherical shell with a diameter of five meters, okay? So, roughly 15 feet. A spherical shell 15 feet in diameter containing, look, if you had, this is saying how you can make a time machine on Wikipedia. You can find out how to make a time machine on Wikipedia. All you have to do is this.  Oh, I was gonna build this my garage later. A person at its center, it continues. A person at its center will travel forward in time faster than distant observers. Okay, so you first have to build a 15 foot spherical ball and put Jupiter inside there. And then, look, then it continues and it says this statement. I'm serious, this is quote, quoting the article on a time machine. This is a direct quote and it's not a joke. It's not a joke. Squeezing the mass of a large planet into such a small structure is not expected to be within humans' capabilities in the near future. Folks, this is what is wrong with science today. Okay, look, this is how Stephen Hawking spent his life. What a waste. What a waste. He spent his life thinking about how to shove Jupiter into a five gallon bucket. That's this, I'm not making this up, this is real. This is real. Look, I have crossed paths with this scientific community several times in the last 20 years of my career and I'm telling you, this is where they're at. This is where they're at. I have worked with engineers that are working on, I mean, can you imagine the pressure? Can you imagine? I mean, look, I've worked with engineers trying to figure out how to make high-pressure steam fit into vessels that we can't, look, we literally hit walls of technology in this world where we cannot manufacture materials that are strong enough to contain the pressures that we can create. Because we can make machines more efficient if we can make these materials stronger and contain higher pressures. And look, these engineers are creating, every single year these engineers are creating different alloys and they're getting better and better and better. They can create alloys, they can create thousands of PSI inside a vessel. And then the next year somebody comes up with another special alloy using minerals from the earth that can create, that can hold higher pressures. It's brilliant. And then we have the people at the university talking about putting Jupiter in a coffee cup. I mean, it's maddening. It's maddening, but this is where they're at today. Look, thermodynamics, which we talked about in the first sermon in this series, how the universe works. Look, that was created by men like, and I'm gonna contrast the difference between the men. It was created by men like Sadie Carnot, like Lord Calvin, or Calvin, I guess it should be called Rudolph Clausius. These are like the fathers of thermodynamics. These men, you say, who's Sadie Carnot?  And that's how your car runs on a thermodynamic cycle. Many of these men that you will find, many, many, many, many of these men that I just named were professing Christians. I'm not saying they were saved. I don't know what their doctrines were. I don't know what their theology were. But to the man, they acknowledged God. To the man, they acknowledged that they were, all that they were doing was trying to figure out the laws that God put in place. Let me give you a quote from William Thompson Kelvin, or better known as Lord Kelvin, if you ever look up or read books on him. He's one of the fathers of thermodynamic theory. This is a quote from him. I have long felt that there was a general impression from the non-scientific world that believes science has discovered ways of explaining all the facts of nature without adopting any definitive belief in a creator. I have never doubted that impression was utterly groundless. He says, I've never doubted that impression was utterly groundless, that science. He says, there's all these people that are non-scientific that are out there. And they think that the scientist is trying to explain away God. And he says, he's one of the most successful, look, he has given us machines today that run our world, this man, in the late 1800s. And he said, that is groundless. And then look what he says on the topic of time. Look what he says. You know who else was coming onto the scene around this time, by the way? A man named Charles Darwin. He said, so Lord Kelvin said that the non-scientific community is starting to think that we're trying to explain away God. He says that's groundless. And then on time, look what he says. One of the smartest men in history says this, we feel that there is no possibility of things going on forever as they have done for the last 6,000 years. Do you understand what this man gave us? This man just said that there's no way things will keep going on forever as they have for the last 6,000 years. He didn't say 2 billion years. He said 6,000 years.  I believe that the earth is just a little over 6,000 years old today. Because that's what the Bible says. But that's what he also said. And you know what's funny? You know what's funny? You know what this man gave us? You know what William Rudolph Kelvin gave us? He gave us the second law of thermodynamics, which basically proves mathematically that the earth cannot go on forever. Mathematically. You can prove mathematically that the earth cannot go on forever. See how the universe works. That's what this man gave us. And he saw it. And look, he unlocked that secret. God unlocked it for him. Look, these men and men like them delivered to the world the things like your car, the things like electricity, the things like basically the physical basis for every machine that we use today. Men like this and the men that I named, they gave us these things. They basically invented the modern world. Turn to Romans chapter one. These men invented the modern world. On the other hand, let me read you a quote from Albert Einstein. Albert Einstein, who is literally worshiped today by scientists and the university culture and crowd out there today. Albert Einstein, quote, the word God to me is nothing more than the expression and product of human weakness. The word God to me is nothing more than the expression and product of human weakness. The Bible, a collection of honorable but still primitive legends, which are nevertheless pretty childish. That's not even good grammar. This is Albert Einstein compared to these other men. Turn to Romans chapter one in verse number 20. Now I'm gonna prove to you not only from the Bible, but from the world that this is all wrong. Look at Romans chapter one in verse number 20. The Bible says for the invisible things of him from the creation of the world are clearly seen. That's what Lord Kelvin saw. Being understood by the things that are made. You know how I know when a scientist understands the things of creation and he understands God? You know how I know when a scientist understands the world from a biblical viewpoint? He can make things. That's how you know. And you can look at these men and you can look at the men that followed, like Albert Einstein, and you can judge them by the things that are made. Because that when they knew God, they glorified him not as God and neither were thankful, but conveyed in their what? In their what? In their realities? No, in their imaginations. Man, if this is not Albert Einstein and his children, I don't know what is. And their foolish heart was darkened, professing themselves to be wise. They became fools. Here's how we know he was wrong. Here's how I know he's wrong. I'm showing you from the Bible how I know he's wrong. Here's how I know he's wrong in the world. Nothing has ever been invented by his theory that he came up with in 1905. Nothing. And I'll leave comments open on this YouTube video and somebody can come up and they can make a comment on something that they thought. Albert Einstein, look. Nothing, no machine, no materials, relativity, special or general has nothing to do with satellites. It has nothing, you need to read more if you think that. It has nothing to do with time dilation as an illusion. Find me a clock that isn't relying on gravity and I'll prove that one wrong. Every clock is relying on gravity. Man will never be able to travel through time. Einstein had nothing to do with atomic energy. Nothing. The only patents he ever received were related to a refrigerator that he didn't even invent. He was a patent clerk. He did the paperwork. His student invents a refrigerator and he filed the paperwork. I mean, it is his most credited equation.  He didn't invent that. That was published in 1889. The equation was actually published by Oliver Heaviestyde in 1889 and later in 1904 and early 1905 by Fritz Hazelnurl. And he published, this man published a trilogy of papers using the equation called On the Theory of Radiation in Moving Bodies. Here's a quote from the Scientific American on Albert Einstein. Then Albert Einstein publishes it a few months later. In reconciling, this is from the Scientific American, hardly a Christian document or publication. In reconciling this equation with his theory of relativity, Einstein approximated away the relativistic bits, leaving an answer one can derive from purely classical physics. You know what you don't do when you're building a bridge or a building or an airplane or a power plant or anything? You don't estimate away stuff. You don't approximate away things. Einstein was notorious for this. Approximating things away and massaging numbers to make his theory fit. That's what he just said. And here's another quote from the Scientific American. One wonders on E equals MC squared. One wonders whether Einstein knew of Hazel Dorrell's work. It is difficult to think he did not, given the bulk of the prize winning trilogy appeared in the most prominent journal of the day. Einstein's work is scientific folklore. That's all it is. And it's weird by the way, how people attribute everything from modern communications to paper towels to Albert Einstein. It is the weirdest thing. It's the strangest thing. But look, he didn't invent this equation. He didn't invent any machines. But look, God has the last laugh. Because professing themselves to be wise, they became fools.  Now we have men like Einstein and then his children, like Neil deGrasse Tyson and Mikio Kaku and all these people, they sit at universities and they theorize about putting Jupiter into a coffee cup. Mikio Kaku talks about like super alien civilizations. I'm serious.   And there's a reason that nothing has ever come from it. There's a reason. Look, here's a statement. I have invented more things than Albert Einstein. You're like, that's pretty prideful to say that. Well, guess what? Go invent one thing and then so have you. It's crazy. It's crazy, but professing themselves to be wise, they became fools. Back to time, God controls time. Time is not a variable, it never will be. God controls it, he uses it. He uses it to manage and motivate us. He uses it to show us the signs, the seasons, the days, the years. Look, it's a tool that he uses and it's a tool that's in his hand for good reason. I mean, when they look, when they look, when they invent the first time machine or they smash Jupiter into a bouncy ball, I will retract the sermon. I'll retract it. I'll be like, you know what, I was wrong about that. I didn't think they'd get Jupiter in there. But look, it's never gonna happen. It's never gonna happen. Look, I have been privileged to see the limits of technology. I've seen the limits of how small we can make a transistor. I've seen the limits. I've seen the limits of wavelengths of light and how we manufacture things. And then I've seen those limits pushed a little further and further and further and further every year. But these guys, they're off in another realm. Science has left the building, folks. We're not gonna control time. And God, look, God not only shows it in this world, he shows it in the Bible that he controls time. And look, he continually makes fools of those that mock him. To believe the theory of special relativity, you literally have to believe that your feet are in the future and your head is in the past.  And it makes perfect sense that God has just like, you know what, you mock me.  And you profess yourself to be wise. And these other men, I love reading about these other men, these past scientists who were just like, you know what, the universe is so great. The more they studied these things, the more they studied the way particles worked and how materials work together and how heat transferred through different materials, they're just like, this is proof of God. That's what you'll find from these men before the Albert Einstein. It reminds me of Matthew 718, where basically, you know, a corrupt tree, just he just keeps bringing forth corrupt fruit. That's science today, unfortunately. God controls time, not us. There will never be a time machine. Sorry to break it to you. You'll have to read about it in books, but you probably shouldn't be reading those books anyway. Let's bow our heads and have a word of prayer.


This is CurzPype. My friends call me Big C. I'm back again guys today I got another free intro for you. However, here's the thing not only is this intro free guys I'm giving away three more custom intros the last guys. I've done their intros. They're done. They're finalized They've got them three more if you like this intro and you want your logo or your channel name in it Let me know. All you got to do is write a comment saying hey pick me and we're gonna go ahead and use heartbeat to pick a random winner Not just one random winner three random winners. So this this intro if you like it put a comment in Let's do it if you don't want this intro But you want to the other intros from the past remember you can just go to the link below click the link and then check out All the different intros and let me know which one you like if you're one of the three winners I will give you my email address, which of course is Curtis at freedom.tm Click that and bam you get your free intro guys. So here it is free intro This is for everybody plus I will customize three lastly a lot of people have been asking how to customize them We can't give away the files and the reason why is because it uses some a little bit of copyright stuff That we don't own the copyright to the music for example or sometimes some of the motion paths are copyrighted And you know what some of the stuff isn't copyrighted, but giving the whole thing away It's kind of against the terms of service and we are pretty legit. We're above board here guys So right now we're gonna do the customization for the three winners plus you can download this intro free and pretty soon We're gonna be releasing templates for you guys as well because that's what we do here All right guys enjoy the free intro download it write your stuff down. Let's do this big see checking out three winners coming up


I'm Rick, follow us on Instagram and Twitter for more juicy content. It's so juicy. It's quite fun. It was a good year. Stings the nostrils. Today, what are we doing, Rick? We are going to react. We are reacting to a video. It's called, I don't want to mispronounce this. Weird title. Yeah. I don't want to mispronounce this. It is pronounced, I'm always guessing so forgive me if I screw it up. Cargo, hero's mother, makes him care on his birthday. I don't know what to call it. I think this is a war. Okay. Between India and Pakistan. It's not just somebody named Cargo Hero? No. I think it's a Cargo Hero. Okay. So like a World War II hero. Okay. I believe that's what it is. And I think it's a Cargo Hero. Okay. So like a World War II hero. Okay. I believe that's what it is. And so this is, I don't know what happened to him. I'm assuming this video will tell us. But it's like a video that makes his mother meet him. Okay. I don't know. What is, what is cure? Do you know? That's why I just said I think it's a war. So his mother makes him war for his birthday? Rick. So think of this like World War II. Okay. World War II hero is mother. Right. So makes him cure. What is cure? I don't know. I don't know what cure is. Got it. This I believe is a war.  Basically. I'm with you. Okay. Here we go. Captain Regent Harper was born on 26 December 1976. When you become a mother you are very happy. You see a beautiful child. She becomes more happy.  The whole school was empty. The last one was Regent Harper. And then he comes home and talks about his friends. That was his everyday job. I said I won't go to the army. I won't go anywhere. Garnet Harper said, if you won't go to the army in the first chance, then remember. Then you won't go to the army. He worked so hard. And he was through in the first chance only. And sometimes I feel, if he didn't go in the first chance, then it's possible. Sometimes he goes to the army.  I don't go to the army for life. I've lived for so many years. But what you achieved in life, it's more important. As a son of course, he was a very fond of his mother. And we were like friends. When you feed Regent, he used to be very happy. And he used to say, if you make it once a week, if you make it once a week, he was very happy. My husband doesn't eat too much sweets. Even my younger son, he eats less sweets. But my son and I were fond of sweets. And he used to make so many sweets that he would store them for 2-3 days. And then he used to eat them for 2-3 days. Now I'll simmer it a little and add sugar to it. This is a small cardamom. It tastes very good. And there's a cup in the middle. This is almonds. Pistachio almonds. This is cashew nuts. Pistachio cashew nuts. So they taste a bit different. If that would have happened, then I would have to add one more thing. And now it's going on the table. We just really like this rich thing. Cashew nuts, cashew nuts, the exercise gym we used to do, this is required for that. I wish Vijay a very, very happy 41st birthday. And I'm sure wherever he is, he's happy. Yeah, that gets you in the feels. Yeah, and that was... Yeah, I just... I can't... I've had moments where I've seen my kids in pain. I can't... I cannot imagine what it's like to lose a child. Especially like that and service to your country at such a young age. And to think he died at 22. He would have been 41.  That's just... God bless all the military and a special portion of blessing on all of those beautiful family members who lost somebody.  Absolutely. Have their love. But it's also almost just as hard, if sometimes harder for the family. The family. The families that they leave back, especially if they're deployed. Yes. And not knowing if they're okay. Yep. And especially if they, you know, if that person dies in service. Right. That, like, it's extremely... You can't even... Especially, like, it's one thing, like, let's say I was in the military and I went off and I died. No, it was my wife and my kids would be extremely sad. But then it's a totally different thing and unfathomable to me to even think of, you know, three months being a father of, like, my son. If he went off to war. Yeah.  I can't even, like, imagine what I would do. I don't know. I've experienced a lot of pain in life and I can say without any hesitation, the worst pain I've ever felt in my life was the pain of knowing my child is in pain in some way. That's... It's just the last thing you want. It's, like, let me be in that pain. I don't want them suffering. It's just...  It's been 20-something years and it's just right there for her. I don't think that goes away. It won't. It won't go away. That's her baby. For example, I've always... Even before, like, when I was a kid and I watched A Lord of the Rings, one of the most quotes that I've ever said. He says, no father should have to bury their son or have to bury their child or for whatever the line is. That's exactly what comes to mind. It's something you shouldn't ever have to think about. It's awful enough to lose your parents but you know that's coming. That's timing. They're old and it's their time but to think of a parent having to raise their son and then them leaving this earth before you leave is just unfathomful. Yeah.  It's mostly chicken dishes. My wife can attest. It's true. It's all chicken dishes. But there's meals and so like... It's just... I'm assuming she does this every single year on just so she can feel like he's there. Yeah. And do it. Do it because people do that all the time. That's one of my... The fact that she said she wishes she didn't make it on the first show. Yeah. Because then he would still be here. Everybody thinks those things. Yeah. If this hadn't happened maybe they would still be there. And I guarantee being a loving mama she's probably wondering was there anything she could have done differently but no this is what he wanted to do. And she says she's a proud mama. Proud mama. I promise you any soldier who's worth their weight will tell you they signed up for that. They know exactly what they were doing and for them in fact there's lots of stories of soldiers coming back and their buddies died and they did and they did not. And they have a really hard... It's survivor's guilt. Really hard time with the fact that they didn't go with their buddies. So yeah man any and everybody in the military we say this every time we do a military video God bless you. You don't get the respect and the love you deserve because it should be poured out to you all the time. Giant. Yeah, giant indeed.


So, I'll be sharing about our experience in using human-centered design as a technique or as an approach to design a comprehensive newborn monitoring chart here in Kenya. This work is embedded in the clinical information network that has a platform for running quality improvement projects in the newborn and pediatric setting. So what is human-centered design? This is a creative approach to problem solving. It's a process that begins with the people. This is very important. The people that you're designing for and ends with new solutions that are purpose-built to suit their needs. And we'll see how this worked out in our setting. But that's the definition by idea. This is a general process. It begins with understanding the context, the problems, exploring ideas, and then materializing these ideas. And the key to remember here with the process is that it's quite iterative. So you can go back and forth between understanding, exploring, and materializing throughout the whole design process and in between each of these processes, each of these steps. There are very many tools that are available for design and not limited to these that are listed here. So I'll give a brief example about personas. But there are things like user story mapping, storytelling, process mapping, role-play, typical interviews that we always do as researchers, observations, among other things. The goal of all these tools is to allow you to be able to articulate the problem and very well understand the context that you're designing for. So we'll go to the project itself that is designing newborn monitoring charts and give this as an example of the application. So the setting is that the newborn care setting where we have a team of caregivers giving care to any newborn at any given time. So you have many people taking care of these newborns, including the doctors, the nurses, the parents, the nutritionists, and other allied healthcare workers. Therefore, it's important to document the care that they give, both for the person who's documenting, for letter reference, and then for others to understand what has happened. However, we have poorly designed charts, as we found in our setting, and many charts captured related information, which leads to duplicated efforts. And as Anne has clearly stated, the health workers are doing so many other tasks, and then it would be important to make this process efficient. And of course, there are other problems around documentation, but the main thing we're going to focus on today is the charts design. This is the process that we used for our design. We split it up into two phases. In phase one, we sought to understand the challenges and do the charts design. And then in phase two, that's between July 2019 and March 2020, was about piloting and changing. And you can see the process here from step one to step six. The point is you begin with understanding, you explore ideas, converge to practical proposals. This we did through three workshops, and then in the last six steps, although we did repeat the sum of the earlier steps, was to develop together, agreeing on what goes into the chart and what doesn't, and then doing the prototyping and changing. And this process goes on and on until you agree, eventually, that you have something that is useful. So like I mentioned, we did this through three workshops and then piloting at four hospitals. And we had also input from a Neonatal Expert meeting. I'll give a little bit of information on the outputs of the workshops and the process. So in understanding the context, what did we do? We went on to use personas as a tool to help us understand who is it we're designing for. And here we found the most common people likely to be the ones taking care of these babies are interns, medical officer interns, and a clinical officer, and of course, the nurse. And the participants of the workshop went about describing these people, including drawing them and understanding what they do. And their goal ultimately for all of them is to provide best practice care to newborns. So in thinking about what then happened during the workshop and piloting, we were able to move from aspirations to workshop outcomes to testing outcomes. Some of the aspirations included nurses and suggesting that we have a chart that could cover, be used to monitor a patient for seven days. This is a paper-based chart and many other things that they wanted to be included. However, we had to build consensus and agree and discuss is this reasonable, a reasonable thing to be asking of the person who's feeling, the personas that we described. If you put something in a chart, you are essentially asking someone to record something in that slot. So we had to critically think back together with the nurses and the pediatricians on these reasonable requests. So this led to our workshop outcomes. And then in the testing outcomes, we ended up changing once more because things didn't quite work out as expected. So the workshop outcomes, we had two charts. One is called a standard monitoring chart. You can use it over four days if you print it in duplex on an A4 chart. So you use day one here to day two here, flip it over and do the same for day three and four. The what we were calling an intensive monitoring chart is just a chart that provides you with more slots, feeling similar information, but a few extra things for the baby who needs closer monitoring. And again, if you print it on both sides, you use one chart for two days. However, we had to come to this merged chart, which now we are calling the comprehensive newborn monitoring chart. The questions that kept coming up were, how do you select which baby needs which chart? If you're going to have two charts in the world, what if a baby is on three-hourly monitoring and then suddenly requires closer monitoring? What happens? So those are practical issues. And then considering resource limitations in our facilities, is it possible that we introduce some level of wastage if we ask them to print two charts and some don't get used and some get used? So and then the complex printing mechanisms in the hospitals, which then asking people to print two charts just complicates everything even further. So this is why we ended up with this one chart that captures everything. An important thing to note here is that this monitoring chart is very different from the vital science chart that you'll find in many other settings here. We combine the feed and fluid prescription and monitoring plus vital science and other assessment all in one place. So what does it mean to implement the new charts? We move from up to even five charts in some places. The proposed version one charts were two. And finally, we end up with just one chart to cover all this information that was being covered by the old charts. So what are my reflections on the head CD process and what we ended up with? We were able to clearly document and understand the problem using the tools that are available. And the head CD process for me and for the team made this idea of the user and the context and practicalities be the important thing that you constantly think about so that whenever suggestions are made, you run them through a filter to understand whether this will be practical or not. And the final question, of course, we ask ourselves or I ask myself is did this work behind the evaluation phase? And one last told me during an interview is that I thought whoever came up with this idea did a very good thing because this comprehensive chart is now able to cover almost everything to each and every baby, whether they need to be in intensive care or standard care. And this for me means that, yes, we did a good thing and we continue to test and make it even better. I'd like to acknowledge the supervisory team and, of course, acknowledge the teams at the hospitals, the nurses, the pediatricians and the research team at the clinical information network here at Camry Welcome Trust for the support and for making all this work possible. If you would like to read more about the entire process, the publication is available online for free access. And you can always read more about what we did in the entire project. Thank you.


This is the team for this project and title has been slightly changed from what you saw originally in the program, simply because Ichikawa also has his own point of view of project, unfortunately Alexei could not come, so I will tell you about our recent results. And then his female is PhD student from our group in Munich. As Volodya Yudson mentioned yesterday, indeed the main idea of this project appeared after careful reading this paper and numerous discussions with authors including of course Boris Alishulio. So I will very briefly summarize what was the main point of Volodya's yesterday talk. I will address one-dimensional systems. And we all know that transport in one-dimensional systems with or without interactions is carried by collective charge density waves, which propagate ballistically in ideal systems, which are clean, but if you add disorder, it can easily pin charge density wave and it can drive system to enslave. And the question is what are exceptions from this general picture? The exception, which Volodya explained yesterday, is related to H transport in two-dimensional time reversal symmetric topological insulators, where there are so-called helical H modes where chirality is locked with spin. So right move has spin up, left move has spin down. And the four, if you put potential scatterer, it is unable to mix these two modes, simply because of spin conservation. So there is no back-scattering from right-moving mode to the left one. And we hope that conductance is immune to localization effects and can remain ideal at least up to some extent. And the question we addressed is, can we expect other setups where a symmetry-protected transport with suppressed back-scattering can appear in purely one-dimensional systems without presence of topological non-trivial bulk? This question I'll address. I will take the model of Conda-Chain, explain physics of Conda-Chain and different regimes in this model. I will explain you how we derive low energy effective theory for it with quantum phase transition, where discrete symmetry spontaneously broken. And at the end, I will address the properties of these two phases separated by quantum phase transition. Let me start with the model. The Conda-Chain is very well known. We have band electrons, which interact with local magnetic moments. So I have exchange interactions. There are many reviews about this model. I will study this model and the following assumptions. Capon is anisotropic. It is of XXZ type. And it is weak. Spin multiplied by any capon constant must be much smaller than the bandwidths of conduction electrons. Must be much smaller than the ultraviolet cut-off of the theory. I will further assume that band is far from half feeling. The array is dense and I will talk mainly about zero temperature limit. Okay. My goal is to develop effective flow energy theory. And to start with, I might go to continuum limit. So first of all, I change from thermionic operators to smooth chiral modes, right-moving particle with a spin either up or down and left-moving particle with any spin. This is absolutely standard. We end up with two direct particles, right-moving particle with plus thermo-velocity, left-moving particle with minus thermo-velocity. And this is, we'll know the grandian of band electrons where the first matrix acts in spin space and the second in chiral one. Okay, now let me analyze most relevant terms in spin-local moment interactions. There are two types of such terms. The first is related with forward scattering accompanied by spin flip. It is nothing else but origin of quantum physics, as you know. The second type of most relevant terms is related to back-scattering. Here I collected all terms. And back-scattering can also be accompanied by spin flip, or it can occur with forward spin flip. And you see that I have put two different captain constants for these two different back-scattering terms. Now I have to assume something about spin configuration and let me at first assume that spin variables are slow as it was done many years ago in well-known paper. What I have after this? All back-scattering terms in the Hamiltonian are multiplied by oscillating exponential. Under my assumption that spins are slow, this exponential is very fast. So it effectively suppresses this term and we are left with forward scattering spin flip, nothing else but quantum physics. But in principle, there is no guarantee that other spin configurations are absent and I may consider the case where spins have 2K Fermi components. After proper choice of spin configuration, I simply put these fast oscillations into spins. Effectively, they reappear in quantum term such that quantum term becomes suppressed and back-scattering term dominates. Back-scattering can open the gap. So this is the regime of gap physics which I will address. The gap physics may dominate, for example, when spin is large and there is no conduit at all, or I can switch on additional electron-electron interactions, repulsions, and if interactions are almost as you to invariant, then the first loop of the RG will tell you that the back-scattering dominates. So there are such cases where this is the main term and I'm going to address these physics right now. So, I expect opening the gap in the Fermi spectrum and after this I have scale separation in the system. There are three scales in space. The smallest scale is related with 2K Fermi oscillations which I'm going to eliminate at first. Then after gap is opened, a coherence lens appears and there are two other regions. Gap fermions live at smaller scales and this is the region of low-energy physics which is my goal. I expect that maybe remaining massless fermions and slow spin components live here and as you will see these two regions may be coupled by massive fluctuations of spin degree of freedom. Now, necessarily, I have already a single out smooth electron degrees of freedom. Now I have to separate scales in spins. I may start with usual parameterization of spin by S2 vector on three-dimensional sphere and let this be one of vectors of orthonormal basis. Then I will do the following trick. I rotate spin, introducing two components, longitudinal and transverse components of new spin and they are characterized by two new angles which I call alpha parallel and alpha perpendicular. Next, I say that let me duplicate variables namely in addition to these two initial angles I allow two new alpha variables to be dynamical degrees of freedom. So I will treat them as independent variables. And I assume that I will be able to single out the fastest oscillations in spin degree of freedom by the composition saying that alpha perpendicular consist of two k-therma oscillations plus some smooth component. What happens now I have four spin degrees of freedom or standard of initial two and of course this is possible if and only if I end up with separation of variables. So at the end, you will see that alpha and psi will be slower spin variables and alpha parallel and theta will be massive spin variables. So nothing bad with this duplication of variables is just the way how to separate degrees of freedom. Okay, now I write down full back scattering term my basic equation with which I will play further and further. I remind you that there are two different types of back scattering without spin flip and with spin flip with two different coupling constants and after I did shift of a perpendicular alpha variable faster oscillations simply disappear. I have included them in alpha. So what remains here already contains no two k-therma oscillations. Now what I expect back scattering must open the gap and the spectrum of fermions after opening the gap I effectively decrease energy of fermions and the ground state energy is minimized when the gap is maximized. So I must find spin configuration which allows me to maximize different back scattering terms. And you see that this effective spin requires that alpha parallel must be close to zero and depending on which term dominates I can have three options for theta variable. It must be close either to zero or to pi over two and which minima is realized depends on ratio of two coupling constants. Let me start with a so-called case of easy access anisotropy when that component of coupling is much, much larger than perpendicular one. So the term with our spin flip dominates and as far as it links all fermions it hybridizes all fermions from left to right and vice versa it can open gaps in spectrum of all Dirac fermions. I expect that this term dominates so alpha is zero, it will be always zero and this term requires theta to be close to pi over two. Next I have to do some technical steps which I will not explain, I will just leave them. I do gauge transformation to gauge out remaining phases from back scattering. I calculate fermionic gap. I integrate out massive fermions which appear to be massive due to back scattering. And finally I integrate out remaining massive fluctuations of spin phases to take into account the normalizations of parameters of my new collective degrees of freedom. So I assume that gauge transformation is done. This is a fermionic gap which comes simply from four by four matrix. Gaps determine fermionic contribution to ground state energy. It is a minus sign so the larger is the gap. Ground state, ground state. The larger the gap is lower ground state energy is and from this cartoon you see that minimum of this contribution is indeed achieved at theta being close to pi over two. Further I can tell or expand ground state energy around this minima and you see that fluctuations of theta and alpha parallel are suppressed. So indeed those two are massive spin variables as I expected in the very beginning. My approach has been preliminary justified. Now I integrate all massive modes, massive fermions, massive spin fluctuations and I end up with effective low energy theory for the case of easy access anisotropy. There are two contributions here. Both are of type of flotting liquid, L stands for flotting liquid and you see that there is pronounced spin charge separation. I have spin density wave which propagates with bare velocity, fermi velocity and I have charge density wave which propagates with velocity being much, much smaller than bare velocity. Correspondently compressibility of charge density wave is also small. The physics of this renormalization of parameters for charging density wave is very simple. Volodya explained it yesterday, I can briefly repeat. Spin phase can rotate freely. I don't know how to draw it better but the main thing is that spinons feel presence of localized electrons and because of this coupling, charge density waves become slow. This is the same picture as Volodya explained yesterday. As concerns configuration of spin waves, we have spin oscillations both in X and Y directions but if I calculate cross correlation functions, I see that X and Y components are not correlated to each other. Now let me add a potential disorder and study stability of charge density wave with respect to this potential disorder which has no spin structure and therefore it links only particles with the same spin. Fermilons which stand here are all gapped fermions. I would like to study property of charge density wave destroyed by alpha so I integrate out massive fermions and after this I end up with sign Gordon model for alpha. Now I recall that Latvinger parameter for alpha degree of freedom is small. Therefore certainly this term is relevant and disorder can pin charge density wave very, very similar to how it happens in usual one-dimensional bias. We come across usual Anderson insulator. The charge density wave is unstable with respect to additional added potential disorder. Now I would like to study the opposite regime where J perpendicular dominates. I remind you equation for the fermionic gap in easy access case and I ask myself a question what happens with this expression at the SU2 symmetric point where two coupling constants become semi equal to each other. If two constants are equal then cosine quadrat plus sine quadrat is one. So for M minus term square root exactly cancels J perpendicular and I see that some gaps go to zero as the SU2 symmetric point. Now I can assume that probably if I go further to the case where J perpendicular dominates only that gap survives and if M minus shrinks to zero it will remain zero in the second. Easy access is a plane. Easy access is a plane. Easy access is the case where JZ dominates and vice versa. So my guess is that this point will be point of quantum phase transition which will separate two different phases. To simplify my life I say that let me consider the case where JZ goes to zero. This is the same equation for back scattering term but now I cross out back scattering without spin flip and I consider back scattering with only spin flip. Sigma minus and sigma plus tell me that here there are two contributions which can be rewritten as helical contributions to back scattering. Again I recall you reminded of helical modes are modes where direction of propagation is locked with spin. This is taken from cosine and if this term dominates in this limit then as usual alpha parallel is zero and I must maximize cosine to open gap as large as possible so I expect theta to be zero. There is second contribution which comes from the sine and the only difference is that as far as I have assigned here then theta must be close to pi not to zero. So I calculate ground state energy, a freemonic contribution to ground state energy in the easy plane configuration and I see that there are two degenerate minima with theta being close to zero and theta being close to pi and depending on which configuration system chooses I can open gap in one or other helical sector, the second helical sector remaining gapless. This is the same situation which I redraw in chiral representation so you see that for one spin right moment particle is gapless, left moment particle is gap and vice versa for second configuration. We can say that there is partial gap opening in the system. Instead of gap for gaps in all branches of chiral freemons now I have only two gaps. Again, I must verify scale separation. I choose some minima. I calculate fluctuations of spin variables around this minima. I see that fluctuations are gap and suppressed so everything is self consistent. I have two massive spin variables as expected. I can go ahead, I can integrate out all massive degrees of freedom but now situation is drastically different from what you saw before. I have two different charge carriers, three helical fermions which are gapless and collective wave which is now coupled to everything to charge and to spin so I can call it charge spin density wave. Three helical fermions of course propagate with bear velocity fermi velocity and collective wave is again slow because of same reasons I explained yesterday kind of polaronic effects. The principle difference between these two phases is also reflected in spin correlations because if now I calculate correlation between Sx and Sy spin components I see that there is local helical order and this local helical order reflects broken helical symmetry. Similar effects were also addressed in talk by Daniel Loss one week ago. Now I'm interested in the question whether after breaking helical symmetry the system can acquire some robustness again localization effect whether we may expect back scattering to be suppressed. So I add again weak scholar disorder which has no spin structure and I see that disorder is able formally link only gap and gapless fermions but matrix element of single particle back scattering would be zero simply because there is no density of state inside of the gap of gap particle. So first conclusion is that single particle back scattering is impossible if I assume spin conservation in the system. Then I do the same as for the case of the axis I integrate out gap fermions. After this I obtain effective back scattering which is multi-particle back scattering you see that I have more fermions those are massive fermions, external mass less fermions and you see that there is spin flip which is hidden inside of a propagator of massive fermions because the gap is opened by scattering with spin flip. I have no full theory for effect of this big scattering in my hands but for simplest estimates I can do the following trick. Let me put expectation value for this exponential and ask whether such multi-particle effects can be strong. We think no because this exponential is always either vanishing or small and before we see that not only single particle back scattering is absent but multi-particle back scattering is also suppressed and this is very similar to suppression of back scattering in time reversal invariant topological insulators so I emphasize that I obtain it due to interaction effects instead of presence of topologically non-trivial bulk. Chairman advices that my time is almost over so these are my conclusions. I have explained you that quantum chain may show quantum phase transition depending on anisotropy in the system. In the case of either plane anisotropy helical symmetry is spontaneously broken and this may lead to noticeable suppression of back scattering which is very, very similar to suppression in edge transport of topological insulators. These are questions which we plan to address further. We still have to explore better robustness of this absence of back scattering deep in the infrared limit and we still do not have full theory of phase transition in the system. Okay, and I see Boris came. So the main conclusion that on behalf of all speakers organize us happy birthday Boris.