My name is Rena Jacob-Peshmir-Rohaz and I'm here to talk about big data or big hype. In our new knowledge society, one of the issues we're facing is how to deal with this big data. We're collecting data from all over the place about Facebook, Twitter, blogs, media. Everything we do is being traced now in a digital way. So we're thinking about how to deal with this amount of data. Research has shown that information today available can be used in different ways. So sectors are looking now into the amount of data they have been collecting over the years in different silos.  We will have financial information, non-financial information. So the idea of big data is collecting all this information and making analysis that could help organizations to move forward and actually to adapt to the new issues that we're facing. Organizations also have to deal with the debate if having enough data, how they're going to deal with the privacy about this data. Organizations are starting to collect information about consumers, the users. So everything has been traced now. So the debate is about how organizations are using our personal data to make their businesses better or to build solutions to make society better. I think organizations are also thinking about if this kind of data that they're using can be used also in different ways, not just about the organization but also make it available to governments to change policy. So big data is actually moving the economy, it's moving society, it's moving governments. So it's moving it also in a positive way and not in a negative way.


So, first of all, I am very grateful to Professor Mahajan to provide this opportunity to share my calculations and results with the experts and also some students. So what I will do is that I will present my calculations as well. But introductory part is also there about the problem which I am doing. It is not directly related with fusion, but it is about hot plasmas and general plasma dynamics. So, our aim is, I will go to the next slide from here. Okay, the aim is to understand the physical mechanism for the generation of seed magnetic field. And then to find out two-dimensional and three-dimensional analytical solutions of two fluid, MHD and neutral fluids equations with given spatial, I mean, the structure on space is assumed to be given by density and temperatures. And then using justifiable assumptions because we are trying to do analytical calculations so we need some assumptions. And to search for a possible mechanism for the generation of vertical flows. I will introduce this problem later. So how the vertical flows are produced in the plasma and to investigate the formation of augured structures such as speakeals in the solar atmosphere. Yes. Okay. So first the observations. The observations show that all galaxies almost have magnetic field large scale magnetic fields of the order of 10 to minus six gauze micro gauze and lower limit on the seed magnetic field is that it should be greater than 10 to minus 25 21 gauze. Therefore people have tried to obtain the seed magnetic field by using plasma dynamics, which must be greater than 10 to minus 21 gauze. And other observations tell us that the material outflows from the plasma in astrophysical environments are very commonly very common and have been observed in many objects. And the first observation is long ago by Curtis in 1918. And there are many other I am just quoting a few just to give you the flavor if you want to consult the literature. And then there are, there is huge amount of literature about sun where the speakeals. Coronal loops, prominences, flares, coronal mass ejections are observed in sun's atmosphere and solar wind also is manifestation of the particle outflow from the plasma. So these are just a pictorial view of the galactic magnetic fields which are on parsec size, large magnetic field scales magnetic field magnitude are small, but scales are very large. In initial laser plasma experiments which were performed with the low power low intensity lasers and in those days in early 70s. The laser intensity was 10 to 12 watt per centimeter square approximately and laser pulse time was in nanoseconds. So the laser hits here, the target solid target. This red is the plasma density gradient is electron density gradient because plasma increases in opposite direction. And if this is the temperature gradient. So the density gradient and temperature gradient here curl of the vector product of density gradient electron density and temperature gradient produces time dependent magnetic field. So this was the basic idea. And these magnetic fields have been observed in initial laser experiments, then in accretion discs the relativistic jets are produced of electron positrons. And they have been observed large, they have large velocities. And this is the jets observed in young stellar objects. Here the plasma is classical and speeds are relatively slow. So now we just discuss to model the plasma outflow and the generation of mechanism for the generation of magnetic field in a simple way, considering the set of two fluid plasma equations. So this these are the electron equations momentum conservation and then I mean density conservation or mass conservation. And similarly these are the equations for ions. And this is equation of state for ideal gas law. And since these equations, these are charged particles. So these fluid equations are coupled with the set of Maxwell's equations. Our aim is to find out analytical solutions of these coupled nonlinear partial differential equations and highlight the physical significance of these solutions briefly with some possible applications. And before doing that, I want to introduce maybe many of you know it very well, but the beer man battery concept. The beer man was trying to explain how the seed magnetic fields are generated in these stars. So in 1950 he presented the idea that if there is temperature gradient and density gradient in electron fluid. And he assumed that this magnetic field is produced on a longer time scale, compared to electron plasma oscillation. So this assumption that always much greater than the time period of electron oscillation, he ignored, we can ignore the electron inertia me tends to zero. And using other part of the assumption that always much smaller than iron plasma oscillation time. He assumed that we can ignore the iron dynamics so ions can be assumed to be static electrons are inertial as so a very narrow window for this. And this term, Lawrence term V e cross B was also neglected just to start with a very simple physical model. So in this under these assumptions, the electron equation of motion becomes very simple equation time electric field balances the pressure electron pressure gradient. If we take curl of this equation. We see that magnetic field is produced, if del n e and del t are independent of time, so then it is very easy to integrate. If we integrate this equation. We obtain this equation 12 which tells that at any time tau later after t zero, the magnitude of magnetic field will be. So del n e divided by any can be written as log any, and that is the cross with delta t. Now application to galactic plasmas. So this theoretical model has been applied to estimate the seed magnetic field generated in galaxies. So, actually, I have said that it is assumed that I am in the background station. This is the model beer man's model, we will see later. So, in this publication, he assumed that the thickness of the cloud because they divide galaxy in columns of different columns of gases large scale. And for example if we consider a column of gas with thickness 10 to two parsec and parsec is you know very large I have mentioned somewhere 10 to 13 kilometers three 10 to 13 kilometers. So if thickness is 10 to two parsec, and he assumed galactic radius 10 to four parsec, then using that equation beer man's battery equation, the magnetic field after time tau will be expressed as equation 30. Now, del n e over any has been estimated as exponential here one over edge. That is the thickness of the cloud and temperature gradient he estimated from edge of the galaxy to the center and he took it 10 to six. 10 to six kelvin and tau that time of galactic is magnetic field generation seed magnetic field generation is approximately the time of formation of galaxies and galaxies are assumed to be formed in first billion years after the creation of the universe. So, during this time, the magnitude of magnetic field turns out to be 10 to minus 17 cows, which is greater than that so that was the seed magnetic field, as Professor Mahajan yesterday was telling that that is then amplified by the dynamite effect to present of micro gauze. Then the same theoretical model was applied to explain the generation of magnetic field in laser plasmas classical laser plasmas. So then that equation can be written in this form as in equation 14. So, assuming that the density gradient temperature gradients have these order, and in those times, the plasma produced had the electron density is 10 to 20 per cubic centimeter, and temperature one KV CS the sound speed turns out to be three into 10 to seven per second, while omega PI is 10 to 13. So, putting all these values, the magnetic field turns out to be 0.6 10 to six cows, and it was completely in agreement with the observations mega Gauss fields were observed in those days in laser plasmas. So computer simulations and other calculations take into account different effects of ions, plasma rotation resistivity many things with simulation. The model, which takes into we all know that there is m hd we have heard a lot of about m hd to fluid model or multi fluid if you have dust then you can increase. And if temperatures are important and micro instabilities and temperature effects appear, then we talk, or we consider the kinetic model kinetic theory. There, and the model, which works in this time scale, where we ignore electron inertia and assume ions to be static is a very narrow window of time. And in this time, we see that electron inertia is ignored ions are assumed to be static. Now, if you look at the laser experiment, you can see that omega PI is 10 to minus 13, and tau, which they assume was about 10 to minus 10, much longer than the ion plasma oscillation time. So that was the initial point from where I started looking at this problem that this is inconsistent to assume ions to be static. But the problem was how to take into account ion dynamics because then the system becomes very complicated. And I don't know computer simulation so we need to formulate problem to do analytically. So these were some comments on beer man battery. First is the as I have shown the inconsistency with the consistency with the application and the theoretical model. The problem is that this Lawrence term B cross V e, as magnetic field is produced as soon as then this term should be operative in the system electron dynamics, and when we apply this model to galaxies for one billion year assuming the town time, and we assume that ions are static. This seems to be maybe for initial calculations it is okay, but one needs to consider all these things. So about emhd, I have written few my comments and calculations, very long time ago, but now in the, and this is the, for me, useful point because most of the work has been done in isolation. So here this is an opportunity to discuss with you people. As I told you that numerical simulations can take into account many effects, which analytically we cannot. But our interest is to find out analytical solutions of plasma equations, which can explain the generation of seed field magnetic field, along with flows, because we want to take into account electron flow flow and flow. And this is just symbolic. This is it means ions can be assumed to be stationary. I am presenting. Yes, I am just presenting beer man battery effect. What is this, and its applications. Now we will. We will discuss on dynamics also I am going to discuss that. Okay, so important point to note is that the magnitude of seed magnetic field produced by density and temperature gradient is very small this we will see in calculations. But the flow produce the vorticity and it is directly related with flow that turns out to be very large. So this is also a point I think the baroque linear vectors, these gradients, they produce large flows in plasma. So two dimensional, actually I started this work when I was visiting Japan, and I write a paper with Professor Yoshida. So in this theoretical model, two dimensional solution. There was one problem which I also noticed later when I understood this problem more deeply that one of the component of the magnetic field. For example, we have three dimensional magnetic field. One of the component remains constant. It means that system has already some magnetic field, and we want to generate magnetic field, so there should not be any magnetic field given. So what I did is that using the same assumptions that cosine neutrality because we are considering large scale dynamics so cosine neutral plasma temperature gradients are there. Now J denotes electron and ion so we will now consider both dynamics and density gradient is also there. So this is produced with these gradients, and they are non parallel, because we want to take curl of these del n cross del t so if they are parallel it will become zero, the mechanism will disappear. So flows, this is the restriction which I impose to simplify the model that long flows are longitudinally uniform said divergence vj divergence of both flows is zero. So we assume that density is constant in time as in beer man battery, but we know that such a system cannot remain independent of time density will also evolve the time, but that is a later problem. Other dimensions and assumptions are same be ignore electron inertia. So in this case, the electron equation of motion becomes 15 equation 15. Here we can be related with iron velocity and curl of B through ampere's law, because when we ignore the displacement current Maxwell's equation reduces to ampere's law and then these velocities are related. So replacing this V e, and you see the curl of equation 15 becomes in this form and here left hand side is the generation of magnetic field on right hand side. The second term is the same as beer man hat, but this term which is non linear v cross B. This is problematic complicated term. And if we replace V e by ampere's law, it becomes in the form of 16. So here we see that left hand side has the time dependent magnetic field. So if non linear terms, one, two, and three, which are very complex complicated. If they vanish, we have the same form as beer man hat, considering the electron equations. And if we look at Einstein's equation and take curl of this equation, it becomes in the form of 17. And again it has these non linear terms very complicated terms. And we have used this classical gas law. Now we look at continuity equation. So if density partial T and is zero as we have assumed that density is time independent, and then flow is longitudinally uniform. And we have an other condition on our flow and density gradient that del n dot V j must be zero. And if we divide with n, we write instead of density, we write psi. So del psi dot V j should be zero. And ampere's law also requires that the gradient of psi dot del cross B must be zero. So these two conditions we need if density is time independent and flow is longitudinally uniform. In addition to these conditions. We also assume that all complicated non linear terms vanish with our solution, which is, which has to be proved. But in the beginning it looks that we have dropped but not we have not dropped. We want to find out structure of psi and temperature gradient in such a way that all these non linear terms automatically vanish. So this we will see later. So we have two equations equation 20. This is just beer man battery and equation 21 tells us that magnetic field is not independent of vorticity. And ions vorticity is linked with the baroclinic vector of ions. And if we add these two term equations are we subtract 20 from 21, we see that the addition of baroclinic vectors of electrons and ions produces ions vorticity, and which is linked with electron velocity as well through ampere's law that we know. So this equation 22 is also an important result. Since we see that vorticity, I am vorticity is linked with magnetic field it can be parallel or anti parallel to the vorticity. So let us assume that magnetic field is directly related with the ions vorticity equation 23. So now we have to choose the form of psi temperature spatial profiles because these are given. And in addition to this, we need to satisfy all the conditions which we have mentioned. First, I just want to see that how non linear terms can vanish. So suppose velocity has this structure that curl of this non linear term vanishes. Okay, we will prove it later but suppose that this vanishes. And this velocity structure has the form that if we take del square, we express it as eta vi and eta is some constant. So these are again two conditions on the velocity. And we will find and see that velocity turns out to be in the form of psi. Therefore, psi should also satisfy the similar equation as 26. So, 24, 25 and 26, along with these conditions that divergence vi is zero, B is proportional to the ions vorticity divergence psi dot vj is zero and divergence psi dot del cross B zero. If these conditions satisfy, then we find a very neat and clean two equations, which produces vorticity and magnetic field. Now I just show that how these non linear terms vanish. If this we have shown that if curl of vi cross del cross vi is zero, then this term del cross vi will be zero because V is the curl of vi. So if this is zero, then del cross vi cross B is zero. Now we look at another equation. That is the vorticity equation we related here. So take curl of this equation 23. Curl of 23 gives del cross B in terms of velocity, and we see the divergence vi is our assumption that it is zero. It means del and del square vi is eta vi. So now we have found one thing in our system that velocity is curl of magnetic field and magnetic field is curl of velocity. So these are the characteristics of our flow and velocity fields. Now this is again a third term. Here it is ions. It is automatically related with the electrons. So yeah, this is the model which I am it is modifying this beer man battery effect from the beginning. That was the other part. This is the second part. So we are taking into account on dynamics. Okay, so this term if we write it becomes in the form of vi cross B curl of it and we have seen in equation 27 that it is zero. So this term also finishes. Now we look the last term that is del psi cross del cross B del cross B. So we just write it in this form and it turns out to be in the form of equation 30. So divergence psi dot B B is equal to del psi cross del T. So this dot product vanishes and this from continuity equation we have seen that they should vanish. So interestingly on all nonlinear terms can vanish if the form of velocity psi and T we found appropriately and that is the main step now that how we can. It is not linear process what is complicated process, but I am trying to simplify the problem to find out analytical solutions but of course, this will just give an insight to the physical processes and I mean, basic mechanism, but people can now try if we put for the physical linear terms, I cannot solve analytically. And also these nonlinear terms I cannot solve. So, okay, I think later on we can discuss but here as an exercise, I am presenting three dimensional solution just a mathematical exercise, I do not have found any application of this but then I will show you the two dimensional solution, it has very interesting in my opinion, very interesting application that we will discuss. So quickly I just tell you one thing you can check because but this is some cumbersome. Three dimensional solution requires a lot of algebra to prove, but two dimensional is very easy. So, this form of psi, I don't know how physical it is or not. So three dimensional solution we just see as mathematical exercise at present, I am trying to find out its application but later. So if psi has this form and T has this form, you see if we take gradient of T, it becomes just constant because this T not j prime is the gradient of temperature which we assume is a constant. So then what happens is this term del psi del Tj because these are the source terms. It has the form of psi because T not j prime comes out of the equation. Cross product and all terms are in the form of psi. So, V i turns out to be in this form equation 34 in three dimension and magnetic field turns out to be in the form of 35. So this is the mathematical expression, its application I am not presenting here and I do not know at present. Now we discuss. Okay, to neutral fluids because it is a simpler set of equations to many equations. So we have more general solution. So here the solution is psi e raised to power alpha plus beta plus gamma. So if I write psi in this form and temperature remains laying linear as earlier, we have again the vorticity produced by this vector and psi has this form and velocity that far. So now I discuss. And that can also be applied to m h d I don't know I have okay so single fluid also but now we do slightly interesting problem with application that is the two dimensional solution which I will present just after this. First we make some background general what we are doing. So if we look at sun sun is divided into two main regions exterior and interior interior has core where the huge thermonuclear reactor exists and energy is produced here. Beyond core is the radiative zone here the gas is almost static and absorption and emission processes are taking place. And then comes the convective zone where the plasma is in motion above convective zone is photosphere. And above chromosphere is Corona even our earth lies in Corona but we will study and discuss Corona closer to the chromosphere just upper. So this is the figure I took from priest book, you can see it. So I just go here to give you some flavor of solar structure for the application so that you can appreciate application. The thickness of the photosphere is approximately 500 kilometer and density is 10 to 13 electron density and temperatures are low. Therefore, neutrals also exist there. And this is the reason that we have visible light mostly visible light from the sun surface and the spectrum of sun although it contains x rays ultraviolet etc. But most of the part and intensity comes in the visible spectrum. The gamma rays which are produced in the core when they pass the radiative zone and emission and absorption processes takes place. And they reach the surface, they turn into visible light long wavelength they become visible light, but these are basically the gamma rays produced in the core. And photos above photosphere is chromosphere. You can imagine 2000 to 2500 is the thickness here density is low temperature is high so it is almost fully ionized plasma neutrals are very few. Beyond chromosphere is Corona and in Corona. This is a mystery, the temperature rises suddenly in a very thin layer of transition region between chromosomes here and Corona. So we are not discussing this here, but still there is a lot of literature on this problem. The temperature has very. Okay, I just show the figure from surface, we go above temperature first decreases, then again increases remains somewhat constant and then it takes a jump. And this is the transition region through which it abruptly increases. And these are the figures about son. These are the speakers now I will apply this two dimensional theoretical model to create the speakers. This is grass like structure as grass on the earth they say so son has the grass of hot plasma. These are plasma tubes cylindrical tubes emerging all the time. And maybe I have shown right here that at any time we if we look at the surface of the sun. There are half a million speakers on this surface. So this is a very common phenomena and one needs to understand what is happening in the plasma here. So this is the two dimensional version of our exact solution, which was published in 2010. Okay, three dimensional is recent, but we don't have any application for that so far. If psi has this structure e raised to power Iota. No, mu x plus new by and plus e raised to power mu x minus new by this is the structure of psi and TJ varies linearly along Z and y direction, then we produce magnetic field. You see here in equation 50 in three dimensional. And the flow also becomes three dimensional, because we are not interested in three dimensional I just want to see the vertical flow how it is produced. So if we suppress this why variation and just consider. Okay, here is. Okay, I will discuss it later. First we take the variation of temperature just along vertical direction because this is the observed. So temperature gradient is given. We are not assuming it now it is given. We just what I think is that if temperature gradient in the system is given in astrophysical labor, it is not the laboratory scale. Here, if density gradients are produced, and they have appropriate form, then the force baroclinic effect force that gives acceleration to the plasma in vertical direction. So this we will just show here that how it happens. Then we see that. Okay, actually, one point is, you have not asked, I just mentioned here, you look at equation 51. The speakers actually have external magnetic field also, because the magnetic field is generated by the sun solar dynamics. And we have studied the magnetic field generation by beer man mechanism or if I'd are extended to include dynamics also. And the two dimensional model which I presented before this, it remains valid, I have checked it if there is a constant magnetic field, but it is just uni direction. If it has more directions, then the model does not work so if it is uni direction so we assume are suppose that these speakers have an external magnetic field along z axis, and the generated magnetic by baroclinic effects. So this is the total magnetic field in this structure, then model remains applicable. And generated magnetic field when we put the appropriate magnitudes of scale lens density gradient scale and temperature gradient scale and magnetic field turns out to be very small generated, but velocity you see at velocity 55 equation. It turns out to be along z axis. So this was the main interest velocity has only one component in the vertical direction, if this is given. So this was the interesting point now point is other that speak you'll have long length. And it is also observation that they move with constant velocity, that is the observed fact. So what I think is that in the bottom of the speak you'll be just consider a plasma slab for example, in x direction it is from zero to XM here just I, I have some time little by 510 minutes I have. Okay, these should not be parallel then problem becomes one dimensional. So I consider just one part, and yes, we assume that density falls like this exponential in x right place. So actually we should consider four coordinates, and then instead of cylinder, we have a scare emerging from the surface of from chromosphere to cover. And then what I assume is that if this is the speak you'll be considered this thickness of the plasma here acceleration produce and move up and one after the other. These structures are formed, and we have a form of speak you'll are cylindrical structure. So this was based on the Cartesian coordinates, and we assume that temperature gradient you see here t prime TZ two minus TZ one, this is the linear scale length, if we divide with the thickness edge. We estimate the gradient of temperature, and the acceleration produced, where is a not a notice to here I assume the temperature equal but ions and electron temperature is not equal. I am temperature is two times electron temperature. Otherwise, it's not but for rough estimate, we see the acceleration upward acceleration. It turns out to be 3.3 1024 centimeter per second, and on solar surface, the solar gravitational acceleration is 2.74 1024 centimeter per second scare, it means that this effect produces a larger acceleration in opposite direction. So my view point is that this structures move in upward direction great with greater acceleration than the solar acceleration, and when they leave this part and reaches here, the gradient disappears either temperature gradient disappears, or density gradient disappears. So they look as if they are moving with constant velocity, because then they are that is the observation. But here the point is that we assume cylindrical flow as scare flow are like this, but I did some work, but at that time I so this is the form of just psi and density. And this is the schematic of that and the flow is only along vertical direction with this. So now I tell you and I forgot to mention here. This is actually a better application in cylindrical coordinates. And we see that there are many conditions on psi velocity and other structures, but luckily, if we look at the psi as function of our theta. And TJ as TJ prime z linear, it remains linear because it is given. So del psi across del TJ turns out to be in the form of 58. This is, and this is the form of magnetic field on our theta plane. So this condition you see I mentioned in previous slides that this must satisfy del square psi, lambda square psi or lambda whatever we call this is some real parameter. And this equation satisfies if psi has this form given in 60, because the vessel functions obey the condition 61 and 62. So this was very fortunate that due to these relations of vessel functions 61 and 62, we can satisfy the Helmholtz equation this is Helmholtz equation. Del square psi equal to some constant psi. So this equation satisfy if psi has this form. So this is the J1 vessel function of order one cos theta. So this psi will also attain zero, I mean, not zero value, it is because and divided by and not if it is equilibrium density, so it becomes one. So at equilibrium, it becomes zero, and I just, okay, so this is the interesting point that again, we produce velocity equation 63 along axial direction. So this form of psi and temperature gradient in vertical direction produces velocity only along that direction. Therefore, it means that cylindrical plasma can have a force in vertical direction and moves upward. So I show you the Helicity becomes zero. This is the form of density. So you see this is in center cylinder here, the flow is broken. So it is not a very uniform type flow at different places the acceleration is produced and plasma moves in upward direction and form of size in this form. So psi has smaller amplitude because we assume this and oh sorry psi was log n normalized so n is exponential psi therefore density amplitude is larger. So I have presented this quickly. So if you comment I think this will be good. This will be good. Actually, this model can produce three dimensional two dimensional magnetic field, it depends upon the choice of side, but at the end, the application of the model, I could find at present. I am discussing with astrophysics, people of astrophysics, and I am thinking that maybe the chronal mass ejection can also be excellent but they say that chronal mass ejection has associated magnetic fields, large magnetic fields and magnetic reconnection etc. So this mechanism can be just an additional effect on it, but that we will look later. But unidirectional flow that is a special case, special solution. X and Y. Yes. The B naught, external magnetic field, we assume is in the Z along Z axis and it is, it turns out that its magnitude, for example on the sun is about 100 Gauss in suppose here, the generated magnetic field is very small 10 to minus seven Gauss. If you put these magnitudes. So this means that basically that is why people say that it is a seed magnetic field, magnetic field produced by Baroque-Linic effect is very small, but flows are produced are very large. So I think it is the mechanism which explains flows more dominantly than the magnetic field. Okay. Virtual particles. Virtual particles. There are three conditions of plasma and as we see in the experiment I have seen the plasma flows for a while. The plasma does not follow? Close for a while. I think Professor Mahajan maybe can explain. But what we are applying this is the, I mean plasma given by nature to us. Maybe experimentalists can answer better than us experimentalists. I have a new idea I don't understand the question. Right. I don't know what is the animation time. What is the animation time? What is the animation time? What is the animation time? What is the animation time? And in fact the animation time is the same. And what is the animation time? So I think here I am mixing the things all together. And sometimes you create the motion. And then you create the motion by making a state. These are some things that are stationary in the system. And you can give them a fun time at them. And I think they are phonons. But I mean they have got these as particle and antisposs hurdle. There are no anti-Polans. You don't need to animate their pola. At least one is best for my knowledge. So one must not extend the concepts to some of the sustained limits once you get it. And, you know, so I don't mean if you're kind of discouraged people when you're taking up new processes, you're sure that's all.


Hello and welcome to NewsClick. I have with me today the award-winning playwright, Vy, who's played the vagina monologues, won the OB Award and she's also a recipient of a Tony Award, wrote two very moving memoirs. The most recent one is a actually very interestingly written book which I hope someday we can spend some time to talk about and it's called The Apology. But there was a previous memoir about six, seven years ago also very moving and this cataloging of one's life I think is very important to you. Welcome to NewsClick, nice to have you with us. Thank you, thrilled to be here. Yes, so I thought the way to begin is that in The Guardian you written a very moving piece called Touch Saved Me From Loneliness, What Will We Become Without It? After I read it I said I have to get in touch with you to talk about this because it's so significant. I want to start by asking you about a paragraph in there where you say at the end of the paragraph, how do we live with this unbearable skin hunger? That phrase really stayed with me, skin hunger. Could you talk a little bit about skin hunger in this global pandemic? Well, I think for me it's a kind of irony of my life in a weird way.  And I think for me I've always felt the way I've known the world is through touch, through kissing, through hugging, through holding, through sex, through contact and absent of it. I have my dear, dear friend that I live with here and I have another friend who's part of our little cohort and tribe and both of them are gay and I adore them and they're my family and occasionally my friend James will jump on top of me and just press himself down on me and just so we both have some kind of physical contact. But for me so much about touch is location, right? It's knowing you're here. It's kind of an existential grounding, like you exist somehow and I hunger for my friends, I hunger for my granddaughters, I hunger for people, their skin, their energy, their vibration and it feels like a really, it's a serious loss to walk the world without that. And I worry, I think there are many fascists, there are AI planners, there are technocrats who would love to see us live here in the screens without touch and without contact and without the collective in a physical sense and I think all revolutions come from the body, right? They come from the kind of the streets and they come from, you know, I'm a child of the 60s, right? Sex, drugs and rock and roll was what birthed me and I get afraid of just everything being in the screen and who will become in that disembodied way. Well, you also say in another very evocative phrase, you say what kind of mutiny is possible in a quarantine? You know, it's true that rebellion is on the streets and you are quite correct to say this touchless future is the fantasy of, you know, the fascists in a way. And yet in the United States, where you are based, it's the far right that's on the streets saying end the lockdown. Give us a sense of the context of Trump, this disease, the lockdown, the fact that there are people on the street saying please let us go out and infect each other. It's just so hard to even try to articulate what is going on in the madness of America right now because it's mad. But again, if you even look, they even the crazy right wingers know that the way to have power is to be in the present with your body on the steps of the Michigan State House, right? With your AK-47s, by the way, amassed. I mean, just imagine if any person of color or a black person showed up with that, what would happen? I mean, it's astounding what world of racism and inequality we are living in right now. I mean, Michael Flynn got free today. Just his case got dropped today. I mean, it's every moment we see these extreme, extreme inequalities of power and justice. But I think what's happening in this country is on one hand, it just utterly terrifying. I think the kind of manifestation of white supremacy, which has of course been here forever, but now has a special agent at the top boiling it and cooking it and catalyzing it and inviting it and celebrating it as far as I can tell. He's unleashed all these forces that have been here. I think what's really disturbing me is to see the way we are killing off black people, brown people and poor people and our essential workers. And they are often one in the same, right? And I've been doing a lot of work with women workers and nurses and restaurant workers and farmers and just we're doing this regular show really trying to look at what is happening to women workers in this country. And I think what I'm very, very disturbed by is to see this kind of invisible genocide that is operating right now, what we call preexisting conditions, right? Which are kind of synonymous with systematic oppressions. So that you look at what are preexisting conditions that are killing people well environmental degradation where people live in the neighborhoods where they are more susceptible to asthma. And so this disease is hurting them diabetes where people don't have the right kind of foods to eat. What's a preexisting condition? Like as all this is going on the right wing is busily eroding women's rights and desecrating abortion rights all over the place. What's another preexisting condition is like their desire to destroy and extract the earth to death. So we're seeing the complete deregulation of lands and press and parks and places that should be preserved. And I think what I am hoping is happening is that people are waking up to understand that we are living in a country where capitalism and the kind of racist patriarchal capitalism has reached a peak. I hope it's a peak because if it goes beyond this we'll all be dead where we have to now make a decision that whatever door this is opening, whatever world this is opening cannot be a world governed by profits over people, commodity over care, where we have to start saying who is actually saving our lives right now? Who are the people who are keeping us able, those of us who are privileged enough to shelter in place? You know it's the workers, it's the farmers, it's the grocery people, it's the janitors, it's the nurses, it's the aides, it's the doctors, it's the people who if you eat meat who are you know working in the poultry plants and the meat plants and those are the people who in my opinion have always been holding this country together and have been the least appreciated, the most underpaid, the most undervalued, the most under cherished and the most unseen. And what I hope is that this is the time where that's all going to change where we are now going to understand that the people who are most essential have to be the most valued and the most paid and the most cherished and the most protected because what we're doing to nurses, I don't know if you saw the demonstration today at the White House where the nurses went and put their all the shoes of the 88 nurses who have already died in this country who didn't need to die. All those women were sent into slaughter or mainly women were sent into slaughter without PPEs, without any protective gear, without masks. There was no reason for that to happen in a country as rich as the United States. Absolutely no reason except for lack of forethought, lack of care, lack of consideration and lack of love and respect for the people who are keeping us alive. I mean I think that's very beautifully said and I know that on social media I've been watching you lifting up the stories of people who are you know the workers who hold things together particularly people in the health field but you know there is a way in which every time there's a tragedy or an emergency we call people in these fields essential workers and then a kind of amnesia sets in when things go back to normal there's a real forgetting. I know that you're trying to make the forgetting impossible but how is this going to be fought in the realm of culture to make people not forget? It's such a good question you know we've been working for years on this thing in One Billion Rising called Women Workers Rising where we've been doing lots of work trying to build coalitions with women workers across various sectors and I think like you said there's moments where people will rise up and they'll care and then of course it but I think now actually there I what I hope and I you know I'm endlessly optimistic I'm one of those beckett people I can't go on I will go on I must go on but I feel like I do believe something has kind of shattered people's denial in this moment even even these beautiful things that are happening every night in New York where people are banging their pots and pans and appreciating workers every day something's going into the consciousness that has to be altering the way people see things and you know I was reading the story the other day of this beautiful woman who works on the MTA she's a conductor on the trains and I don't know her story just really devastated me how she was going to work every day and of course they had no protective gear and they gave them these shoddy masks that didn't work and there were no bathrooms that had water to wash her hands and of course she got sick and she got sick for two weeks and when she came back beautiful workers who she had loved were missing and she she said you know like we do our jobs we like our jobs we don't hate our jobs we actually like the work we do but we want to be respected for the work we do we want to be honored for the work we do and we want to be cared for like everybody else and she wasn't saying like I hate my job I don't want to be doing this I think part of what we have to do is start asking ourselves do we want to live in a culture in a society where we respect each other equally where we honor the work that people do and we pay for that work and we value that work or do we want to keep in this awfully hierarchical capitalist structure where people are they're basically are seen as kind of slaves to the ruling class who will just do their bidding be sacrificed at the altar you know they're not essential workers they're sacrificial workers and they'll just be thrown out there and and and for the very very very small you know one percent or even 0.1 percent who is willing to sacrifice everybody for their pleasures and for their advancement and I don't know I don't think I've ever felt more strongly in this moment that we have to turn our reality away from this very very very small section of people owning the world at the expense of the majority of people who are making the world happen and and giving their lives for the world to happen without care and without sustenance and without love really you know there's a an American economist Nancy Faulberg who said that Adam Smith you know his phrase the invisible hand that's all very well but the economy actually works through an invisible heart and she said this is often women in society totally and if you look at it 80 percent of our essential workers are women and women of color and so it is really women you know who are holding up our culture who are moving the work forward and even even what's happening you know with with schools and with this kind of um this notion that we somehow now can do everything online with teaching right this I find also very very nervous making because I will tell you something if we start eliminating teachers if we start thinking that teachers don't have value which I I think teachers are up there with nurses like up they're critical critical critical um then what's going to happen to women mothers are now going to be responsible for teaching their children and schooling their children at home online so what's that going to do to women and work what's that going to do to putting women back into the house what's that going to do to what's that going to do to teachers and and and the value of teaching and the value of an educator who has gone and trained how to be an educator and I think again women's work is totally devalued and yet we're completely dependent on it completely dependent and totally expendable right and this is the story of women in general we we we know that we can't live without them that if women were to stop and I keep saying let's just all stop and see what happens the world would fall to its knees and yet there is no recompense there is no valuing of mothering of teaching of nursing of domestic of of domestic work of nannies of caretakers of people in nursing homes people who actually women who actually make our lives possible and that goes down to farm workers that we can just go down the list and to me um this is where the world has to flip they have I really think that um we have to start moving into I've been dreaming of this idea of what does it mean to live um what would it mean to be an essentialist to live a life of what's essential to have only what you need in terms of things that are essential to have food that is essential to honor the people who are most essential and doing the most essential work to live in with only essential words you know poetry is essential language right what would it mean if we started to dream of um you know do you really have to take that flight is it essential right do you really have to buy that thing is it essential um and and what about our essential workers they would be our queens they would be the people we we we honored and and we celebrated and we cherished and we paid right I like that I mean you know I I for a while thought of you as a prophet because when nobody thought Donald Trump could win an election you said he's going to win we have to stop him and then uh you wrote such a brilliant essay called Trump a fable for the book strong men in which you um basically compare Trump to a virus I know isn't that crazy it's you are a prophet I hope you realize that at the end of the essay and I just want you to remark we can you know come to an end with this because at the end of the essay you I don't know if you even remember this but you talk about the antidote to the virus the virus being hate really Trump has the embodiment of hate and you say that the air the way to get rid of the virus is with people essentially touching they made each other laugh and rub and healed each other with special oils and rituals and prayers they lay with each other and shared their dreams they listened to each other's stories and made amends and reparations here's the antidote and then you write an essay called clutch save me from loneliness please help me understand what's coming next you know it's very strange about Trump I I have this very I just had a very weird understanding of him and what he would bring and what he would be because as I said in that very first meeting he is a hologram he is he he there's something about America that Americans don't even understand which is that we really don't exist at all except in the future we have no past because we have amnesia we have no history because we blotted everything we've ever done out that was bad or wrong we don't have a present because capitalism only exists as a future mechanism of what we only exist in this dream of what will come and so he was the perfect perfect deliverer of the imagined future right make America great again now that's a futuristic idea even though there was no antecedent to it right there was no there was a past to that but it was a futuristic notion based on some nostalgia for the future we've always been nostalgic for right and and and that got implanted into us through Hollywood through you know commercialism through consumption through we will be this America and people come to this country and despite every piece of evidence in front of them that there are no jobs that it's racist that there's this people are like no there's this dream and we're going to commit to this dream and we're going to ride this dream and it doesn't matter and and so to me I guess what I feel is happening right now is is the dream has collapsed there is a complete collapse of the dream and and as painful as it is for so many people I know that many many many people have never lived that dream have never been part of that dream have never believed that dream and most people most people in this country and so I think before we can begin to create the new world and and the new vision we have to get rid of this this thing that's really occupied people I remember once they were interviewing a man who had just lost his job in a big plant where he'd worked for 27 years right and he was sitting in his his trailer and they asked him you just got fired how do you feel and he said well I screwed up I failed I I didn't I wasn't able to get the American dream I screwed up it never occurred to him that his union that didn't exist or the factory that had hired him for 27 years and just laid him off with no benefits or had failed it was his failure because the dream was so all pervasive and so almighty in that consciousness and I think until that collapses that that illusion that whatever that thing is that possesses people we can't really be we can't be at square at square at the beginning point together and I think in a way that's what we're in the process of doing is stripping away stripping away so that we're at the beginning point and I think as as this is happening the viral leader just gets more viral and even to the point where his his head person today had the virus right his head you know what what is his valet right and and and it's getting closer and closer and closer you know the virus to the viral to the viral leader I guess we shall say because he is a virus he is a virus look at him he's just like a he's always scary scary viral well one of the nice things we is that your prophetic voice at the end says we're at the point of stripping everything away and maybe restarting let's very much hope that this is a new beginning and not it has to be because otherwise yeah me too well look it can go either way it really can go either way and it's really up to us all of us um particularly progressives to really ensure that this is a door opening and I don't think we can rely on parties or democrats or any of that we as progressives and there are so many of us people who really believe in a different way of living in this world you know we're racism we're sexism we're homophobia transphobia we're ableism we're all of the things we've been fighting fighting and fighting to stop right we all have to now say we're going to come together now we are going to demand that what this virus is teaching us those lessons get followed through when this is over there's no return to quote normal there was never normal normal was dysfunctional for the majority of people we have to now say we want to go forward into the new imaginative possible place which involves the majority of people having water right now 20 million americans have no water it's anticipated that 120 million americans will not have water because why the water companies the bills get turned off and they don't turn that back on water is not a private it the fact that it's been privatized is insanity right so we're not people aren't gonna have water they're not gonna have food they're not gonna have jobs we all have to start saying why are we accepting this we are the majority of people we we we have to demand that people have health care that people have food that people have water that people have education and that people have community those are the essentials and that everybody lives with those basic things and comfort so people don't have to live in fear and panic to me that's what's got to come out of this and we all have to be willing to really fight for that in the ways that we haven't thought we've got to get out of our comfort we've got to get out of like laying back and hoping it happens you know this is the time now to to move new ideas to move a new way into into the new ground because those those on the other side are taking it and they're gonna take it fast if we don't move that's great thank you so much you


Everybody forced here ripping 2023 Bowman Baseball Sapphire 10 box full case number nine There are the results on screen. Let's go ahead and get started. Good luck everybody recap color and autos at the end Let's do it that one. Is it uh, I don't know that one got you by the Sonics Number two or would have been would it be a Chet Holmgren first of the actual Sonics? Holiday Arias orange to 50 Wilbur Sanchez white socks. I don't know where Sean cameras drafted Sean Kelly my next guest. He's the only other like probably Pretty highly drafted Sonic. I could think of Colby Thomas Luis Rodriguez Zavala and Bishop Graham Frias green to 60 Jefferson Rojas Cubs There you go cubbies and Simon Juan The Zandra Rodriguez I'm Ari on Boyd. How you Lee and Fraley Encarnacion Davis paroza Rojas Axel Sanchez Wilbur Sanchez Mikey Romero first woman auto Kansas City is La Zandra Rodriguez. There's a sooner there Can you see what the first hit nice nice nice? Javier Osorio glitter figure a O Michael Arroyo and Christian Vauquero Sidenio Simone Aqua Hector Rodriguez at 55 for the Reds first Bowman Sit on Raffaella All right decent first box It's all right need some bigger cards though. Come on you near Garcia Montecino orange to 50 pirates Henry Davis Landro Arias Davis and the Los Santos Luis Garcia Cam Cali are alert or down to the Los Santos Luis Lara Cole Young Khalil Watson and Roman Anthony Logan Wagner Yulbar Herrera Wow Two of ten purple first bowman auto this one's going to Alvin with the Mariners Michael Arroyo Holy crap Alvin come on man Auto looks pretty clean to me That's big my friend. That's a big card and Luciano I got a card's name for that one Charles Clifford green Montecino to 60 Padres Lake is it you're gonna stop thundering a lighting anytime at all soon.  He's under a blanket with flashlight that he's who spy as Lazaro Montez Dylan Array Matt Mervis De La Cruz Paroso William Lugo to 55 Mets first Bowman Aqua and I want Chacon Zack Neto Munoz Spencer Jones and Christian Hernandez Tavares Bayez Jesus Bayez first Bowman auto New York Mets Alex Ramirez Juan almost Ruben Santana Aqua to 55 Kennedy Corona first Bowman for the Stroze and Luis on a la Cunha Jace Bowen Pedro Ramirez Parada and Jace young Randy De Jesus Juan Brito Miro Shinjig Martinez and heavy Ramos Marcus Lee saying Eric Brown, Jr. Jose the Paula five at 25 purple first Bowman for the Dodgers Purple is the color here y'all Mike K with the Dodgers Big card Mike Kenny Gomez there Corona Fernandez Al Monte in the Paula actor Rodriguez Anthony Piguero green Junior Garcia to 60 Dodgers and Yonjela Ponte we're gonna have to Get a raft to get it here. I think I can kind of see the other the truck across the parking lot now though A few like 10 minutes ago. I could not see it across the parking lot It's the kind of rain you you literally just don't even drive it. He's pull over Myer Cabrera orange Mike you're a marita 50 Red Sox Coloss to Mar Johnson Jackson choreo Edwin Arroyo Xavier Isaac Jason Dominguez Colson Montgomery Manuel Beltre and Ryan Acuna. We'll have Donnie do the Benjamin Franklin experiment I'm a kite with the key attached to it Michelle de Sons that gel off auto Padres first woman is Daniel Montecino Donnie's the play for I during the day one of these days Drew Gilbert, Mechia Carlos Jorge and Dion Jorge He's just play for like an hour one day before we go in Jorge Ruiz Justin Hennie Malloy green Axel Sanchez the 60 Mariners first bowman And Christian Sarada Crawford Robert Perez, Jr. Max Muncie followed by a red First bowman Luis Garcia four of ten J's Jeffrey H with Toronto now. There we go Oh Lionel James Brooks Lee Gabriel Martinez Juan Alonso All right box five here Susak mess messa Sweeney and Janelle Avena coming arrow first. There's an aqua auto Lissandra Rodriguez to 99 for the Royals There you go. There's an Anthony Gutierrez as well James Wood Brady House Moises by Haceros and Abdi Estella Cruz Artin Gonzalez jet Williams aqua for the Marlins is Anthony Pagueros six of 55 on the first and a frame a de Leon poaca Grego Elarte Gabriel Gonzalez Anna Louise Garcia to 25 now for the blue J's Red and a blue or a red and a purple. Sorry all the bases blue Bastidas Brock Jones Burgos and Artega Radha Julian Loller Jacob Berry Drew Jones Go for Goya green Austin Charles the 60 Royals Royals having a nice break What advisory Gavin Cross? You don't say It came a little late with that one A news desk of Sean so Breaking news such as flood warnings and trash list updates That's pretty true Young Gil Fernandez Riccardo Perez orange Michael Arroyo to 50 Hey, hey, there you go Alvin 20 Blanco, Jr. Von and he might go 4080. I think you might go 4080 Got he's used by as Lazarus Montez Dylan Array and Matt Mervis Spencer Jones Ellie de la Cruz Vincent Peruzzo and Juan Chacon Neto Munoz purple, Jr. Garcia book and 25 Dodgers Christian Hernandez I'm B. Oras Tavares Joshua Baez green auto to 50 Montecino Padres Alchemyres you guys Anybody gonna be watching the late in sports cards annual hot by eating a contest tomorrow Pedro Mires Juan Olmos Ruben Santana and Luis and hella Cunha got Martinez Bowen Parada and Jayce Young Randy De Jesus Juan Brito green the 60 Rangers first moment Alejandro Osuna And Henry Ramos Past the eyes has a flying colors are in the 2022 preseason one run in particular against Denver when he slipped Alvante sang air Brown, Jr. Kenny Gomez. I'll say breeze all Corona Fernandez green Ricardo Perez ten of sixty first woman Phillies Jose de Paula Hector Rodriguez Anthony Piguero Cam Collier first woman auto Heck yes, since see now You go reds been a reds kind of night They've hit something pretty nice in every single baseball break tonight young hella Ponte Collier Damian Pierce or It's not gonna be Kenneth Walker again, is it not trying to trick me a Royal Meyer first woman Marcos Cabrera and Oscar Colas To Mar Johnson Jackson choreo Brian Acuna and Xavier Isaac the main guys Colson Montgomery Orange Jayce young forty seven to fifty Tigers and well Beltry Carlos Jorge might Michelle de Sons that gal off Jason choreo Gilbert Mejia. There's a Salando to 55 first woman Marlins Aqua the honor right Elijah green Miguel blaze orange to 50 Luis and hella Cunha rangers Chase the louder some guests and running back 2022 preseason one in particular against Denver Ladies Jordan Kumar Rocker Colton Couser at William Lugo Max Wagner Kyle Harrison Leandro Arias and your first Solano Union Garcia Daniel Montecino green is 60 Frederick Ben Cosme Orioles Your Don Adela Santos Watson Davis and the Los Santos Luis Garcia Cam Collier Luis Laura Cole young first woman auto Jorge Ruiz angels and Roman Anthony first Well, I already know who that is that's Sam Yeah, Logan Wagner Gilbert Herrera aqua to 55 Marcos Cabrera Yankees And Marco Luciano and Cosme Austin Charles Ryan Clifford and Blake Lube a Ruiz Maloy Orange Figuero Rangers to 50 nice guard first moment and a Christian Serda Gabriel Martinez Justin Crawford Max Muncie and Robert Perez, Jr. Lionel James Brooks Lee on hell's your now and Juan Alonso Daniel Susak Andres Mesa aqua to 55 Red Sox Marcello Meyer As I go one to Trey Sweeney Bayeceros Avena you need coming arrow and Anthony Gutierrez Wood Brady house orange junior coming arrow out of the 25 Wow Tampa Bay raised Chris s big-time coming arrow. He's One of the best performers so far the 2023 first Bowman class That's big. What a case. This has been I'm Diaz de la Cruz. This has been an insane case Joe Oh Our team Gonzales Jet Williams purple Kenny Gomez the 25 Astros And for me they own Board of Ghosts Poca Grego Gabriel Gonzales and Daniel Guilarte Alright last box One sec actually realize the game was turned so far. Have you guys can told me? Stitas Brock Jones Jacob Barry and our taga column Zab He's got a Zaxby's Radha Julianne Aqua Jorge Ruiz the 99 first Bowman auto angels. It's a luller arias Drew Jones Gregorian cross we got a red coming up Mercedes Zavala holiday First it's a red You know Garcia Dodgers to 10 Man Dodgers killed it too had the purple de Paula and Now a red first Garcia sad is calling us a bot. Oh, man. Oh, man.  What are you playing for? How you leave Peyton Graham Frias and Simon Juan? Los Andro Rodriguez and Mario void Axel Sanchez and Karnaz. He owned tonight 3m. All right, Sean. I'm maybe not 3 a.m. Close to it. Henry Davis, Parosa Aqua at a 55 Edwin Arroyo for the Reds There's a piece of dust on the oh and his name will get that off before we get sleep for you He better be we'll squat at 2 30 a.m. I'm in Sean's always on after we leave. I'm usually on for like I'd say half the time I get on for a yeah That's dangerous though. It's not a couple games can Uh Yeah, a couple games could lead you to like 3 30 a.m. Okay autos first up Ruiz Montecino Bayez Los Andro Rodriguez Aqua Ruiz for the Angels of 99 Rodriguez Royals green to 50 auto Montecino Padres Now parallels green is 60 Fernandez been Cosme Perez Osuna Austin Charles Axel Sanchez Union Garcia Montecino Jefferson Rojas aqua to 55 Edwin Arroyo Marcello Meyer Marcos Cabrera Yolfri Solano Anthony Piguero Kennedy Corona William Lugo and Hector Rodriguez Orange to 50 figure Rao Luis and hella Cunha Jayce young Michael Arroyo Mikey Romero Henry Davis Wilbur Sanchez purple to 25 Kenny Gomez Union Garcia Louise Garcia and Jose the Paula You get that one mad for your Dodgers We had red the 10 Louise Garcia blue jays red to 10 Union Garcia Dodgers Cam Collier base auto reds Monster commie narrow to 25 first woman orange sapphire auto for Tampa Bay for 25 and a 10 Michael Arroyo first woman purple auto for the Mariners Now we'll do it. Thanks again everybody. We are moving on now. Thank you. Thank you


And this is a good point to take a few questions, we have gone about one hour without questions. So, let us take some live questions then I will take chat. S V U college Tirupati. Hello sir, my question is on database connectivity is that how can we connect the remote databases in remote location using PHP or any other language and what kind of connectivity is to be used for that. So, the question is how do we connect to a remote database using PHP and what kind of connectivity. Now, first of all the standard protocol to connect to a database whether it is local on your own machine or elsewhere there are several protocols for Java its JDBC, ODBC was the standard for C and pretty much all the scripting languages like PHP have their own version of the ODBC API and they also have some other API. So, PHP there is another API called the peer API for connecting to databases. So, internally you know they provide an API and the way they talk to the database is using the ODBC connectivity that the database provides. So, that is what you would do use the API for whatever language you are using and it does not matter whether the database is local or remote you can use the same thing. Now, the many databases also provide proprietary protocols and tools correspondingly. So, Oracle has its own connectivity protocol and if you are using Oracle tools you could use that, but if you want to use Java then you probably cannot use that. So, just to wrap up there is also other ways of accessing data remotely there are what are called web services which in the simplest avatar means you do a URL get on a particular URL and you get data back this is the simplest avatar of web services there are much more complex versions and that web page which you get back is not necessarily a HTML page, but maybe you get back JSON data or you get XML data. So, this is called a web service where the goal is that particular URL is invoked with some parameters and the response is not intended for direct display, but for consumption by a program. So, instead of low level database access you might instead use a web service like this and build your own interface to that database to implement whatever functionality you want. So, you know that is kind of what sort of what we do when we build an application in this case the end user is a actual user the user is interacting through web interface, but if the end user were a program then equivalent thing can still be done using HTTP or other protocols. Mount Zion Tamil Nadu please go ahead Mount Zion. Sir my question is how to touch this how I am creating a new database and how and where I should start normalization sir it is a question we are waiting for last two days can you able to tell me about that sir. So, the question is when you want to create a new database how and where do you do normalization when you want to build a database for some application. The first step is to understand the needs of that application and you know the whole process is laid out in the project proposal that is part of the sample project proposal document to make sure you follow the steps which are required in building a new system you do not jump straight into normalization. You first put down what all functionality you need in English or in whatever language you prefer and then you sketch out the kinds of data which you need to store then you do an entity relationship modeling of that application then you convert to relations and then you figure out what all functional dependencies and multi-value dependencies there are and see if there is any violation of normal form and that is where the normalization process happens. So, part of this is figuring out what functional dependencies hold not just now, but are likely to hold continue to hold if something is not likely to hold it may change tomorrow it is probably better to not take note of it when you design the schema because you could get into trouble. Like I said if you assume that students are in one department, but you believe there is a chance that tomorrow students may be in two departments you should not use that functional dependency, but for our colleges we know pretty much that students are given a department and that is their major. So, that is perfectly fine for us, but if you have some other thing which you are not sure of let us say advisors we currently have only one advisor per student, but you know tomorrow that may change we may want to have two advisors then that is not something you want to put into the design itself. So, do not use that particular functional dependency during schema design after that the steps of normalization you know looking at the dependencies figuring out whether it is in BCNF or 3NF and so forth those can be used as is for the moment let us go back to query processing and then I will come back to the quiz. So, we saw sorting with external memory and it is pretty efficient today people can sort a terabyte relation in a few minutes time on parallel machines with multiple disks. There is some interesting history here at one time a gigabyte was thought to be big. So, they said here is a benchmark called a gigabyte sort and let us see how fast you can sort it. Now, a gigabyte main memory was unimaginable back then main memories were 10, 20 megabytes in size and so that was a benchmark about 5 to 7 years after that benchmark was launched a main memory sizes grew to 1 gigabyte it was expensive back then, but it was available 1 gigabyte memory today of course, every one of us has 1 gigabyte on a desktop. So, in fact many gigabytes so the 1 gigabyte sort benchmark turned into an in memory sort rather than an external memory sort. So, now you have much larger sizes and so the current benchmarks are terabyte, but now there are people with a terabyte memory. So, those have to probably go to 10 terabyte or something. So, coming back that was sorting now let us focus on join algorithms. There are many different ways of doing joins the simplest is nested loop join let us start with that and then we will look at alternative. So, this nested loops join is applicable regardless of the join condition I am going to do a theta join what does that mean this is essentially R join S on some condition it natural join is a special case of this with projection, but this is the most general case this could be any condition R dot a less than b and R dot c equal to R dot d and some function of R dot a is greater than some other function of R dot a comma S dot b and so forth could be a arbitrarily complex condition. Regardless of how complex it is we can always do nested loop join for each tuple t R in R for each tuple t as in S for two nested for loops test the pair of tuples to see if they satisfy the join condition if they do output the concatenated tuples to the result that is it this is a very simple algorithm and R the outer loop is called the outer relation the relation in the inner loop is called the inner relation. So, this is very general, but also very expensive because it is quadratic. So, it is not feasible in for any large relations although occasionally there is a very complex join condition with small relations where you are forced to do this, but if it is two large relations this is going to be horribly expensive. So, the next algorithm is a index nested loops join which is actually fairly simple the edits I made to this slide did not make it, but just look at this here this thing says for each tuple t R in outer relation R use the index to look up tuples in S that satisfies the join condition. What do we do this the join condition had better be something which the index in support and the most common case of this is equi joint R dot A equal to S dot B. Let us say R is the outer S is the inner and I have an index on S dot B. Now, for each tuple in the outer relation R I will take that tuple look at its R dot A value I will use the index on S dot B to find all matching S tuples and then output all the pairs that all those S tuples with that particular R tuple. Then I will move to the next R tuple do this and so forth through all the R tuples. So, this is the outer loop here for each tuple in the relation R. So, I am going to skip the details of the join cost, but it is essentially the cost is the number of matching. So, C is the average cost of traversing index finding all matching S tuples. If there are many matching S tuples the cost C could be higher. So, essentially the number of records in outer relation times the cost of traversing index and finding matching records on average which is denoted as C. So, if the index is you know on disc in the relation is very large with small memory each index traversal could involve some higher. So, C could be fairly expensive because it may involve on average one or more seeks per lookup. So, index necessary loops join can be very efficient if N R is small, but if N R is very large this one seek per outer record can blow up in your face and become very expensive. There are alternatives though which work when the relation N R is large there are lot of records the first of which is merge join is very very easy to understand. So, the first step is to sort both relations from the join attribute may be they are stored sorted in which case there is no need to sort. Otherwise we run external merge sort and get the sorted output. So, here is the relation R which is sorted on attribute a 1 can see a b d d f m q. Similarly, relation S sorted on this join attribute in this case a 1 equal S R dot a 1 equal to S dot a 1 is the join condition. So, we have sorted this also on a 1 and now the merge join is very very easy. We simply keep a pointer to the first record here the first record here they match. So, immediately output this pair a 3 a capital A is the first output if it were a natural join the two copies of a 1 would be replaced by one copy. So, the output would be a 3 capital A. So, for natural join we can just do the projection immediately. Now, what do I do I will move this pointer to the next record b is that 1 equal to this a it is not it is b it is larger. At this point I have to move this record to the next larger 1 which is b and I get b b which is a match. So, that will be output next what do I do I move this record again to the next one which is c does not match no which is smaller b. So, I move that 1 and I get d to d and c match no which is smaller c is smaller. So, I move that pointer to the next one d now we have a match d 8 with d matches and I will output it. Now, if I look ahead here the next one is m, but here the next one is still d it is not changed. So, actually I need to do a little bit of look ahead to find which all records here have the same value and which all records have the same value. So, if there are they say 3 records here with the a 1 value as d and 2 records here with a 1 value as d all of them match both these match all 3 here. So, I essentially have to do a cross product of this subset this one matching with all 3 here this one matching with all 3 here in this case there is just 1. So, I have to output this one d 8 d n and also d 13 d n. So, 2 things have to be output then moving on I find f and m f is smaller I move ahead to m m m match that is output I move ahead here to q this one has nothing that is it. So, it is very easy merge join is a very very simple algorithm very intuitive if you are familiar with the merge operation merge join is a very simple extension. It is also very efficient you know the total cost is basically just transferring all the blocks and we will skip the details of the seeks. If the relations are sorted it is super efficient if the relations are not sorted when you have to add the cost of sorting. And the last major technique is hash join hashing technique which we did cover earlier we will explain it in the context of hash join. Now, this particular hash join algorithm is also just like for merge join it is applicable for equi joints and natural join. What is an equi join it has a condition such as r dot a equal to s dot b. You can also have more multiple attributes being equated you can have r dot a equal to s dot b and r dot c equal to s dot d. We can sort on these pairs of attributes r will be sorted on a comma c while s will be sorted on b comma d and then do the matching. So, we will ignore those details for now. So, now, what is the hash join do the first step is to use the hash function to partition tuples. What is the goal of partition the figure is to break this large relation r and this other potentially large relation s into pieces such that at least the smaller relations pieces fit in memory. So, my goal is to break it into enough pieces such that s s is the smaller relation here and I want each of the pieces of s to fit in memory. So, that determines the number of partitions that I need to create and I will choose the hashing function appropriately. How do I do that typically I have a hash function which generates a value from let us say 1 to max and then I find the number of partitions I need I know the size of s I know the size of memory size of s divided by size of memory plus some fudge factor to allow for non uniform breakup will give me the number of partitions that I want. Supposing s is 100 blocks memory is 10 blocks I will do 100 by 10 which is 10 partitions and assuming some non uniformity say 20 percent I will create 12 partitions here. Now, the number of partitions of r has to be exactly the same in fact the partitioning function is exactly the same. So, I will use the same hash function to partition r and s in the case of r it will be applied on the join attributes of r in the case of s it will be applied on the join attributes of s. Now, what is important is that the partitioning is done on the join attributes and if I had 2 tuples 1 in r and 1 in s which would have satisfied the join condition. What can I say the join attributes values would have been the same therefore, the hash functions would be the same if 2 tuples at all could match both of them will hash to the same value i. In other words if I had a pair of matching tuples in r and s both will land up in the same partition number if that s tuple lines up in 1 that r tuple will land up in 1 if that s tuple lines up in 3 that r tuple would land up in 3. In other words once I have done this partitioning I only need to match tuples in r 0 with tuples in s 0 tuples in r 0 cannot match with tuples in s 1 s 2 s 3 and so forth. They can only match s 0 similarly tuples in r 0 can only match tuples in s 1 and vice versa tuples in s 0 can only match tuples in r 0 not any others. So, I can do the joins locally between r 0 s 0 r 1 s 1 r 2 s 2 and so forth. Furthermore this relation s 0 s 1 and so forth each of them fits in memory. So, how do I finish that join it is described here the first step it is to partition r and s with hashing we have already discussed that. Now, for each i we will load s i into memory and build an in memory hash index on it on the join attribute. The hash index will use a different hash function from the earlier one because in the earlier hash function all of these tuples map to the same value i. So, I cannot reuse that hash function I will use some other hash function and build a hash index. Now, I will read the tuples in r 1 block at a time and then consider the tuples 1 at a time. For each tuple r I will use the same in memory hash function which I use for s i and locate the matching tuples using the in memory hash index. And I will compare the actual values not just the hash value and assuming they match I will output the concatenation as the join result. And that is pretty much it that is the hash join algorithm very very simple. So, the basic idea is partition the relations into smaller pieces such that each s i fits in memory then I load each s i 1 i at a time load s i fully into memory build a hash index that is called the build input s. Then I take the tuples of r and probe the index which I have built just now in memory index. So, r is called the probe input and then I will find matches and output them more on to the next r tuple. Note that if I look at this picture r i does not have to fit in memory because I am not reading all of r i into memory at a time. Only the s i's have to fit in memory. So, that is it that is the hash join algorithm. There are some more details in the book which I am going to skip and the next step. So, hash join merge join both will work for equi joints and natural joints which are a special case of equi joints. Anyway the equi joints plus projection. Now, what about other conditions which are complex? First all I said if the condition is too complex I may have to do nested loops, but it is actually not so bad. Supposing I have a conjunction of conditions where one of the conditions at least is equi joint. Then I can use the one of the algorithm merge join hash join index nested loop join on that condition theta i and what about the remaining conditions theta 1 to theta i minus 1 and then theta i plus 1 through theta n. What about those conditions? I will use them as filters on tuples that match this join condition. So, it is actually better than what it looks like which means fall back to nested loops join. So, if I have a condition which is equi join and another condition where r dot a less than s dot b I will first apply the equi join and matching tuples will be filtered. Let us wrap up the other operations. I want to finish this up in the next 5 minutes and after the break we can move on to optimization. So, the other operations are all done very easily using sorting and hashing. The first is duplicate elimination. I think it is very obvious that if you sort all the duplicates will come together. The only question is what do we sort on? The answer is you sort on all attributes. That will ensure that 2 tuples which are identical will be adjacent to each other in the sort order. Once I have sorted on all attributes I just can and when I see a new tuple I see if it is equal to the previous tuple. If it is new output it, if it is the same as the previous tuple skip it and keep going. So, that is sorting. Hashing can also be done similarly. The trick here is that we use hash partitioning to break the relation into pieces where each piece will fit in memory and the trick here is once I have partitioned it into pieces which will fit in memory. I build a hash index on that relation. As I am building the hash index I will see if this tuple is already present in the index. If it is I will not even add it to an index I will just throw it off it is a duplicate. If it is not present I add it to the index and I output it. So, it is very simple. If this went by too fast for you go read it up from the slides of the book. Projection operation is basically the first step is removing unnecessary attributes. The second step is duplicate elimination which we just saw. That is very simple. The next major operation is aggregation. Now, if you remember the aggregate operation how did we do it? We first got the records which have the same group together. We had to group the relation. If you recall how we group the relation in our example we simply sorted it. The moment we sorted all the sort on what is the question? We started on the group by attributes. If you sort on the group by attributes all the records with the same value for the group by will come together. It would be nice if I could flip to the other slide on define which gives an example of the group by operation. But it is too slow switching between slides here. But I hope you remember that we brought we sorted on the department attribute to bring all tuples for the same all instructor tuples for the same department together. Now, if you want to find the sum count min max all those tuples are adjacent to each other. I hope you can see this example now. This was take instructor group by department and output average. So, what have we done here? We have sorted on department name and now the first one is biology. Then if you want to find the average we actually do the sum and count separately and we will output the average when we move to a new group. So, the first step is we take the first tuple biology sum is initially 72000 count is 1. The next one is comp size. So, there are no more tuples in biology I will output salary sum of salary divided by count of salary which is average in this case it is 72000. So, we will output biology 72000. Moving forward it is comp size initially the sum is 75000 count is 1. Then I add 65000 I get 1,40,000 count 2. Then I add 92000 I will get 2,32,000 count 3. Then the next one is electrical engineering. So, I have reached the end of the group I output comp size with the 2,42,000 divided by 3. Moving forward I get electrical engineering 80000 count 1 that is only tuple I output it similarly finance and so forth. So, in a single pass keeping just a couple of variables for sum and count I have been able to output the average. Similarly, min max and so on can also be done very easily using very few variables. If I want to find median or few other things like that which are called holistic I may have to load all of these values into memory sort them and then find the median. Again there are tricks for median which involve presorting this. So, I can compute all the aggregates I am interested in pretty efficiently by sorting. I can also do it using hashing for lack of time I would not cover all those details come back here. Then there are set operations maybe I should spend 1 second on aggregation using hashing. The basic idea is as I get tuples I will build a hashing index on the group by attributes and when I get a new tuple I will add to the sum or the count or I will update the min or the max and scan through all the tuples and keep putting stuff into the index. Now, as long as the number of groups is small this hashing index will fit in memory. The hashing index is on the group by attribute, but it stores the aggregates computed so far some count min max. Now, if the number of groups is small this hash table fits in memory and it is actually very very efficient even I do not even have to do sorting one single pass on the data and I am done. So, it is actually a very good algorithm, but if the number of groups might exceed the amount of memory I have available it gets into trouble. So, then there are variants which deal with it I would not get into the details. Set operations union is straight forward again duplicate elimination is only extra step here. I am going to skip details of intersection set difference and so on for lack of time and what I am going to do is wrap up maybe we should give you a break for there are a couple of things more I need to do a little behind time. So, I will break here for your t break.


Hello, so I'm recording this video on April 7th. Things may change by the time you actually see this video. But all my videos are being pushed over to the library website lbry.tv. And my username is middlex1000 there. You should check out my videos over there as well. But I wanted to see if I could just play a video or download a video using YouTube DL. And you would think that a website like this, it'd be, YouTube DL works on a lot of websites. It works great. A website like this, they have a download button right here to download the MP4. So you would think that YouTube DL would work with this. So I should just be able to take that URL, paste it in here with YouTube DL and it should start downloading it. But it doesn't. It throws an error. And yes, I am running, if I sudo YouTube DL dash capital U, it will show you that I'm up to date. You know, the version I'm running is just over a week old. So great. So I started, I decided just for fun, I'm going to write a script that will download, even though I can just click on that button there. But I wanted a script that would be able to either download or play using MPV, a YouTube or a library link without having to go to the web browser and just do it from the shell. And I actually did write a script using phantomjs, which I use for scraping websites, phantomjs is very easy to use. It took me maybe five, definitely less than 10 minutes to figure it out and I was able to get the URL. And then I went back to, I was getting ready to record this video to show you that script, which maybe I should, because it'd just be a good, good lesson. But I just, just double check, I ran YouTube DL again and realized it actually is giving me this unsupported link here. And that is the link, except for it's the embedded link rather than the download link. So for example, if I was to MPV that URL, it's going to throw an error because MPV is gonna try to either play that or use YouTube DL. But if I was to change where it says embed to download, it will start playing that video. And saying what W get, I can W get that URL and now I'm downloading the video. Let's go ahead and just remove what just started to download. So obviously YouTube DL is trying to maybe at some point that link worked, but it has been updated to look for that download link. It's looking at the embed link, which isn't working. So I don't even need to write a whole script. I can just grab what YouTube DL is outputting, like this, and use awk and grep or whatever tools I need to get this information. Now this is a standard error out. So to pipe that into another program, I'm going to have to go to pipe, space pipe, and then put my next command in parentheses, which is a little weird. I've never done that. I've piped standard error out to a file, but I'm not sure if I ever piped it like this before. But let's just go ahead and use this and we'll just say awk and we'll say to print the fourth column. So it's going to go one, two, three, four. Okay, that's great. But it's also going to show other lines in this that we want. We don't want that. So I am just going to use tail dash n1 to get the last line. So here we go, we should get that URL. Now all we have to do is use something like said to substitute. This is going onto a new line. Let me make this a little bigger. There we go. So it's a little easier to read here. So we're set. And now I could say embed and replace that with download. Problem with that is what if the title of the video has the word embed in it. So we're going to say find embed that has forward slashes around it and replace it with download with forward slashes around it. And now we should get our download URL. And that's a direct link even though it doesn't have an MP4 extension. That is our MP4 URL. So I should be able to wrap this in dollar sign parentheses and quotation marks. And I can say something like MPV. And now I'm able to start streaming that video using MPV. Again, not with the link to the MP4 but to the video URL up here. And see the big thing is this right here this randomly generated string. That's what I needed to get from the page. And originally I scraped it from the page but YouTube DL actually did that for me. See it found it here and it tried to find the URL but instead of using download again it did embed. So now I can pass it. Now I could obviously clean up the script so that this URL isn't in the middle here. But let's do it on a one liner. How about that? Instead of putting the URL in here I can say dollar sign URL. And then at the beginning of this I'm going to say read dash. Well, I'm not in bash, I'm in yeah, okay. Anyway, I'm just going to say URL. And now usually if you're in bash read has a dash P option to put a prompt in there. I'm in Z shell here which wouldn't matter if I was writing this as script but it doesn't seem to have the prompt or at least the switch for it is different. So I'm just going to say echo enter URL, okay. And we'll even put a dash in there. So we're going to say enter URL with a space, no new line. Then we're going to wait for the URL to be entered, put it into a variable called URL and then run that through our script there. So now I can hit enter on this and ask for that URL. I should be able to go here, copy any video's URL, enter it there, hit enter and theoretically it should start playing that video after a few seconds. There we go. Now YouTube DL does take a moment to go through that because it's basically throwing an error. So my script actually ripping it might be better but I was just like I went through writing my own script and then realizing that YouTube DL is 99% there which means probably with the next update they're probably going to fix that because it gets all the information it needs it just needs to change that. Anyway, this is just a quick video to look over that. Again, it's going to be a while before this video gets out so it probably be fixed by the time but just something to think of, think about writing your own script is useful and again mine probably would run a little quicker than this since this is throwing errors and going kind of slow but look at the error output when a program doesn't run properly read what the error say they're there for a reason and I just saw unsupported URL and I saw that it was this I thought was just saying that it doesn't support library but then I realized it's actually grabbing the right information 99% there. Anyway, just thought I'm actually going to go to the YouTube DL page right now and see if there is you know, there's probably a error, a bug report on this already. I'm going to check it out and see what it says but while I was thinking about it while I was working on this, I thought I'd share what I came up with. So again, and you know, someone who doesn't understand the shell is going to look at this and go, oh, that's crazy. I don't want to type that every time. The thing is you don't. I can just type in, I can say something like alias LBRY equals and I can give it a command like this. I think that should work. No, because it's running stuff. I actually throw it into a function. I should be able to say function LBRY this. Let's see if that works. Normally I'd throw it into a script file. I'm just seeing if this works. So now I should say LBRY. Nope, that didn't work. Now I just kind of messed up the end of this video. Anyway, I thank you for watching and I hope that you have a great day.