We use the word ownership, in other words, in a fairly imprecise way sometimes, but when I talk about property rights and about ownership, I'm talking about, at least in theory, a fully defined, fully owned set of rights, which includes then all the rights that go along with exclusivity. The central thesis of the whole property rights theory or property rights paradigm is rather simple. I think sometimes it's deceptively simple or even too simple. It seems too easy to be true and yet, as I'm going to get into in just a minute, the evidence is all there to suggest that, in fact, it does work the way the theory would indicate that it's supposed to work. The principal point is simply that, to the extent that rights are not fully and privately defined, economic performance suffers. I'm going to talk only about the economic performance part of this. Obviously there's an entire portion of the debate that concerns individual freedom, individual liberty and what have you, and I don't mean to ignore that, obviously it's part of the entire debate, but it's not the part that I'm going to touch on here. To the extent that rights are not fully and privately defined, economic performance suffers, and by suffers I simply mean that if rights were rearranged to provide for full, private definition of ownership, we could get more output, we could produce more from any given level of inputs, from any given level of resources. And that's then what I'm going to look at when I come around to talk about the empirical evidence. To what extent is that really true? Now one might ask at the start, what's so special about private rights? Why couldn't we have equivalent or even better results from government ownership of resources? Why couldn't or why wouldn't governmental ownership produce exactly the same levels of output, same quality, same performance from any given level of resources or of inputs? And the answer, as I didn't explain in any detail here, not to this group anyway, is that unless one has full ownership of one's property, one doesn't have the incentive to make the most productive use of the property. And by incentive, I very definitely mean to include the incentive to gather information, which is a costly process, the gathering of information, unless one has full ownership, one does not have the incentive to gather information about the best use of one's property in the first place. So there are two sorts of incentives at work, first the incentive to gather information to determine what the best use of the property is, and secondly then the incentive to put the property to that use. To the extent that rights are fully owned, the profits, the gains, from seeking out information and from putting property to the best use are realized by the owner of the property. It is frequently contended that incentives of the sort provided by private property are not necessary as long as we can under a governmental system force workers to do the right thing, in quotes, whatever the right things might be. There are several problems with that scheme. In particular, the monitoring of workers is costly. And since it's costly, monitoring will not achieve the same results that self-direction auto gestion, I guess, would be the word, would achieve in a system where full ownership of property, including in this case ownership by labor of the rights of work, is in private hands. But even more important, I think, and here we go right back to the central point of the whole property rights paradigm, someone has to, if we're talking about a governmental system, someone has to monitor and force productive inputs, productive resources to do the right things, whatever those right things may be. As the incentive, who has the information to do the monitoring to enforce the rules and regulations? Right thesis, the only person who has the full incentive to do that is someone who owns the rights to the gains from the gathering of the information and from the monitoring of the workers. And yet, by definition in public enterprise, the gains from doing that. So to talk about governmental ownership is merely to move back one stage in the inquiry, but to then have to pose the same question all over again. If the resources, if the rights of the profits are not fully owned, who is going to assume the responsibility? Why should we expect the sorts of outcomes that we want then to occur? It's exactly on this point then that the theory of property rights has developed into a more narrowly focused economic theory of the firm. Here I would refer you for those who are interested in a broader exposition of the theory behind this to chapter five in Henri LaPage's Viva Proprieté. There you'll see spelled out much more carefully than I am going to do in just 20 seconds here of the whole theory of the firm property rights notion. In essence, the point that I want to make here is that the agents or managers of the owners have an incentive to make the most productive use of inputs, labor inputs, capital inputs. And again, incentives include the incentive to gather information about what uses are the most productive, are the most profitable. Information is just an input like any other input. In the governmentally owned, if we want to use that term, I'll use them interchangeably, those incentives are lacking. Instead, political incentives replace market incentives. As an example to move us into the empirical questions that I now want to address, there was an interesting study done in the United States hospitals and governmentally owned hospitals. Public hospitals, the publicly owned hospitals were more expensive, principally because the administrators of government hospitals who were publicly employed, bureaucratically employed administrators in more beds, in more capital equipment. And why was that? Well, because politicians can more easily count beds and they can count machines and they can see what's being done with the money that's allocated to the hospital. Decision maker, though, in the case of the public enterprise is the politician. And what one produces in a public hospital then is done to please the politician or the governmental agency that watches over the hospital. Hospitals is the patients, not the politicians, who have to be satisfied. In private hospitals, there tend to be more intangibles, more personal care, different levels of care for different kinds of problems. In the public hospital, you have the same level of care provided across the board. That's as much as I want to say about the theoretical background right now. My interest really is more in the empirical evidence as I've noted. And so let's turn to that evidence right now. I should say at the beginning that the literature on this point is vast. There are more studies out there than we could talk about if we had twice the amount of time that we do today. Limit myself to some of the studies done of the situations where public and private enterprises are found side by side in the United States. But I will mention to you that there are similar studies that have been done in England, recently, for example, some comparisons of the production of coal in England by private companies and by the governmental coal producing firms. Therefore that many situations have arisen that we will not be able to get to talk to today, I'm only going to mention some of them. Perhaps in the discussion afterwards, we can bring out some more. Most important and interesting work that's been done, I think, concerns, comparisons that have been made of the relative level of efficiency or of output in private as compared to public organizations. Taking as one example, differences in output that one observes in the production of oysters, oysters of all things. Oysters turn out to be an interesting situation because there are different degrees, different variations of property rights in the production of oysters, in the different states of the United States. So it furnishes a very useful and rich sort of natural experiment to look at what difference it makes to have private versus public production. No one owns oyster beds. They're open to everyone, anybody can come in and use them, but no one has any exclusive right whatsoever. There is no sale of oyster beds, there is no renting. There is no way to make contracts for the use of them. They're owned by no one, they belong to the public. In other states, oyster beds are sold privately or are leased, very long term leases that end up then being very similar to ownership, full ownership. And the leases for the oyster beds are transferable. So there we have something that comes relatively close to approximating fully defined private property in the oyster beds. Several studies then have gone in from oyster beds when they are owned publicly or when they are owned only privately. And they have faster beds are consistently more productive, the better defined, the more private rights there are in production from the oyster beds, the higher the productivity is. What's particularly interesting I think about some of these studies is the environmental aspect of them. Because a big concern in sea life, at least in the United States, is the concern that people will take, whatever they might be, too soon before they have a chance to regenerate and produce the next generation of shellfish. And so the comparisons of the different systems of producing oysters have looked to see whether or not reproduction and the timing of the taking of the oysters differs as you go from private ownership to public ownership. And in fact, there is a big difference. As long as no one owns the oyster beds, as long as the oysters are there for the taking, the person who gets the oysters is the person who gets there first. You can't wait around and let the oysters procreate and reproduce if you expect to pull any oysters up yourself. Someone else will come before you. And consequently, in the publicly owned oyster beds, the harvest date is much earlier. The size and the age of the oysters taken is besides as much smaller, the date of the harvest is much earlier. And not surprisingly then the catch is smaller, which brings us back to the point that I made before, that the productivity overall is less. One reason the productivity is less in other words is that the fishermen move in too early and take the oysters when they're too small. And finally, as might be expected, since the overall catch is smaller and the amount of reproduction is less, the incomes of oyster fishermen are lower in the states that don't define any sorts of private property rights in oyster beds. And that all pretty much hangs together. It's what you would expect to happen. In a way, you might say this isn't a real test of public versus private enterprise, since there really is no governmental firm that's out there competing with private firms. I think the tests are interesting nevertheless, but we can turn to some empirical evidence on the precise question of public and private firms where both are in fact in existence. And that's what I want to do now, as I mentioned, several other areas where we observe both private and public firms in the United States. One area that has been very useful for study has been comparison of water companies. In many municipalities in the United States, the water company is privately owned. In many municipalities, on the other hand, the water company is publicly owned. One study in particular compared 24 private and 88 public water companies as to their operating costs. And they found that the operating costs were much higher in the public enterprises. The productivity of labor, on the other hand, was higher in private firms. Our public firms with the productivity of labor is higher in private firms. Making the evidence as graphic and stark as possible, the study looked at the period 1965 to 1970 to measure these operating costs. And during that time, one firm that was public went private, and one firm that was private went public. So the study looked to see what happened in particular to those two firms that changed their property rights system during the period on the study. And the results are quite interesting. The public firm, its output per employee, found that its productivity, that is, its output per employee, fell by 40%. Quite a significant difference. Thank you. That's not what I mean by the phrase here. Yes, I mean that the government simply took it over and ran it as a public enterprise. Thank you. That's an important qualification, obviously. I'm not talking about going public in the sense of issuing shares. I'm talking about a change in the property rights for private to public. Thanks. Another study that was done by Peter Pashigian of the University of Chicago looked at private and public ownership of municipal transport, municipal bus system. Interesting case because the whole raison d'etre of a municipal transport system, it is said, certainly of a public transport system, is to us and not to bring their cars into town. Stop auto pollution. Stop congestion in the streets and what have you. Pashigian then looked to see, using the period 1960 through 1970, for 40 different cities, some of which had private transport, some of which had public transport, a bus ride. And Pashigian found that there was a significant difference that, in fact, had a significantly higher ratio of bus riders to put, in this case, the bus, if you will, one bus, riders per bus, was higher for the private firm than it was for the public firm. I want to come back and talk a little bit more about this study about public ownership of buses in just a minute. For the moment, though, I will just note that the evidence there is quite consistent with the evidence from the water companies as to the effect on productivity of having the means of transport owned privately rather than publicly. There have been several studies done that relative efficiencies of privately owned airlines and publicly owned airlines. One that I think is particularly interesting is one that was done about 10 years ago, comparing the performance of two airlines in Australia, one publicly owned, one privately owned. The system in Australia is particularly interesting because the government, the owner of the public airline, all kinds of laws competing in lots of different ways with the public airline. For example, they're to charge the same rates as the public airline. The cities in which they land and take off must be the same, airlines must fly the same number of flights between each city. The public and the private airlines typically have to have the same hours of departure. So you go to the airport and you'll find two airplanes, one private and one public. They're in all senses, at least as far as the law can make them the same. They are in all senses the same, except that one is publicly owned and one is privately owned. The situation is even more bizarre than that. The government itself, when its employees, when the bureaucrats fly, is required to have them fly half the time on the public airline, half the time on the private airline, so as not to favor one over the other. They have to have the same size airplanes. When he buys a new airplane, a new model, a different type, moves up from a 727 to a 747. The airline can't introduce the new model until the other airline has had a chance to buy the same model and introduce it at exactly the same time. Similarity in the two airlines, Duke University, Dave Davies, looked at three passengers carried and he looked at those year by year, significantly higher product years as a whole. And what's particularly remarkable is, and in each one of the three measures of productivity that I just mentioned, so you had, in effect, 45 years, three each, and the private airline was consistently higher. Yes, sir? The freight and courier, passenger, and revenue, go into some detail on that particular study because it was particularly carefully done, and also because, as I mentioned, the conditions under which the private airline was forced to operate were rather extreme. And yet, these two airlines with only one real difference between them, everything else is the same. The only difference being that the one is privately owned and the one is publicly owned. And the results are absolutely astonishing. Services that both private companies and governmental companies tend to produce, one that's of interest to me, in particular, that being the area of fire protection or firefighting services, firemen, about one aspect of that in just a minute. Right now, let me mention, though, that there was a study done, the level of operating costs of private firefighting companies with the costs of publicly owned firefighting companies in the United States. And in the United States now, more and more, there are private firms that cities can hire to do their firefighting for them. So again, we have a fairly rich, natural experiment that allows comparison of the different means of operating and the different levels of efficiency of these two kinds of enterprises. The study that I mentioned now that was done about 10 years ago found that private firefighting firms experience only about one half of cities that maintain their own firefighting services. It's twice as expensive, in other words, for a city to hire its own firemen and maintain its own fire companies as compared to contracting with private companies for the same level of service. I might add that there is now tremendous competition, even among companies, in providing private fire services to the cities in the United States, where that kind of competition is allowed, one particularly interesting phenomenon is that even in the very small towns, 25,000 people maybe, one observes that there is no natural monopoly in firefighting. It is not the case that a single firefighting firm ends up serving the entire city. Rather, you'll find two or three companies, private companies competing with one another, contracting with different people to provide for firefighting service. So it does not appear that there is even any sort of natural monopoly rationale for cities' continued insistence on providing their own firefighting. Lastly, I'll mention a rather humble but nevertheless necessary service that many cities provide, that being garbage collection. But there, too, are willing to come around and pick up the trash if they're allowed to compete. One study using St. Louis, the city of St. Louis, considerably lower in communities that use, across the United States, the importance, such as the size of the city and the number of people in the city and how much garbage they generate every year. There are statistics on such things, apparently. Collection of garbage, of these studies that compare the cost of collecting trash, and I won't mention them here. Some of them find that the savings are even greater than 30%. Some find that the savings are more on the order of 50%. The same saving it apparently obtains when you have private firefighting service. That's enough, I think, to give you the general idea as to levels of efficiency. Private firms appear to be much more efficient in general. I will mention that there is one very interesting piece of work that was done on Canadian railroads where you have private railroads competing with the Canadian National Railway. There, there was no difference found in the levels of efficiency of the private and the public enterprise. It's the only such conclusion that I've ever seen. It's the one exception to the rule that private enterprise does seem to operate more efficiently at a lower cost, but in the interest of objectivity, I will mention that there is that one study. I will note, too, though, that there is no suggestion that the governmental railroad was in any way superior. It was simply that it was not inferior in the way that the other government entities had been found to be, as I just mentioned. There are different, there are other interesting empirical phenomena that go along with this question of public versus private enterprise. And I'll just mention a couple of them here. As I say, we can talk more about some of these in the question period afterwards if we like. One phenomenon that is found repeatedly in the comparison of private and public enterprises is the fact that the pricing of certain services done by public entities, done by governmental firms, tends to reflect the relative power who are able to have government alter the prices that are charged to them for the services that they purchase. You find this, for example, in the case of electric utilities. There are many electric companies in the United States that are privately owned. There are many that are publicly owned. In all firms, the prices to large users are lower because there are apparently economies of scale in producing electric power. But public enterprises charge much lower prices to their big industrial users than do private enterprise. Public enterprise, in other words, takes into account the political power within the municipality of the large industrial user and lowers the prices to that large user accordingly. It doesn't have to worry about political pressure or certainly worries less about the political pressure that a big user can generate. It does not underprice electricity to the large user, but rather charges a higher price. When we talk about electric companies, it's the way in which public enterprises charge different prices depending on whether the user of the electricity can vote or not vote. Many electric companies, in addition to serving their own city, also have some users that lie in the next county or in the next city. And they tend to serve those customers as well because they're nearby and it's profitable to do so. But the users that are outside the political jurisdiction are charged a higher price when the provider is a public enterprise, but that does not tend to happen when the provider is a private enterprise. So again, the pricing reflects the degree of political strength in the jurisdiction where the public enterprise is located. I might add that the same kind of, let's call it two parts, is found with the water companies. Once again, if the water company is governmentally owned and it's selling water to users inside the city and outside the city, it tends to charge a higher price to those outside the city than to those inside the city who, of course, have some political power through the right to vote when we compare private and public companies. What we have comes from the electric companies, and as you might predict at this point, the studies, there was one in particular I'm thinking of that looked at all every single private and public electric company in the United States in 1969, and it compared their rates of adopting new electric generation technology as that technology became available after World War II, and it found that private firms adopted new technology much faster and tended to adopt it also on a greater scale than did the public enterprise. There are many other aspects to this question of how public and private enterprise is different. We haven't talked about wage rates. We haven't talked about rates of profit. We haven't talked about a lot of different things on which there has been a considerable amount of work done. Let me set that whole question aside, though, for the moment, and ask the second question that I said that I wanted to address, and that is, works so well, why do we have so much public enterprise? To me, at least, the answer is, in part, obvious. The most obvious reason is because politicians themselves benefit from public ownership, owns an appreciable or significant total resources or the total wealth of society, trivial as compared to the total amount of wealth that the government owns in society, of the way in which government makes its money. For example, it becomes wealthier, but it cannot be said that those who are taxed at the same time find themselves wealthier. George Stigler recently observed, it might be true that Henry Ford worth of wealth with two billion dollars was absolutely nothing compared to the benefit that he conferred on the world from the increased ability to produce automobiles at much lower cost of resources, de-concentrated ownership of wealth. On the other hand, it creates a significant portion of society in its hands, and that portion of wealth that's concentrated in the hands of government is in effect concentrated in the hands of politicians who run the government. And I should say here that although I use the term politician and certainly not here to praise the role that politicians play in the running of public enterprise, I'm not suggesting that there's anything morally wrong or that I would do anything different if I were a politician. We have structured the incentive such that we get the outcomes that in effect we've provided for. We have allowed the laws to be written that define the rights in many cases to use the resources publicly. And if we have allowed that to happen, that's our fault. We shouldn't blame those who take advantage of the opportunities that are presented. Resources are resources that are controlled either by politicians directly or indirectly through the bureaucracy, which answers to the politicians. The more resources a politician controls, the more a politician can use those resources to benefit the persons, the organizations that the politician wants to benefit and by benefiting organizations, the politicians make their living. That's their job.  And much of this giving of money is completely legal. I'm not suggesting that this is an illegal activity at all. There are many ways in which politicians can be compensated directly for the sorts of benefits that they provide. The real issue then, I think, is to identify and to benefit use resources in one way as opposed to another to begin to understand we have allowed these kinds of public enterprises to be a lot more work done. Why did that happen? Why was it allowed to happen? It happened as an outcome of a democratic process. And yet the results, if what I'm quoting in these various studies is true, the results are quite unfavorable to us as a society. Why then did it happen? Who gains and who loses? There have been a number of studies equations in the United States. There have been many done elsewhere, but I'm going to stick to the American evidence to try to identify how this process works. How has it been that public enterprise arises? In the United States, most of the governmental ownership, outright ownership, the sources occurs at the municipal level. The national government regulates, and in many ways that's similar to public ownership, but it's more interesting to look at the municipalities because in the United States the municipalities themselves own the electric companies, the water companies, the firefighting services and whatever it might be. What I want to do then is to talk about two or three historical instances where public ownership did arise as a producing various kinds of goods and services. I mentioned earlier the study that was done of private versus public bus transportation. It was found in that study that the shift from private to public ownership of municipal transit depended on the voting of the users of the buses. As the number of users of the buses rose, the chances of the city taking over the bus lines increased. Think of the situation that that places the owner of the bus in. As he becomes more and more popular and provides better service so that more and more people ride the bus, the people to whom he provides the service increasingly go down to city hall for the city itself to take over the buses. Why do they do that? Well, because as soon as they take over the buses, they start to subsidize them. And so municipal ownership of the bus lines is just an indirect way then for cities to subsidize the riders of buses. And that in fact is what the historical evidence shows. First the ridership on the buses rose, then the city took them over, the prices then were slashed. And that's why we got public ownership of the bus lines. Purely as an outcome of a political process. Another example that's been studied quite a lot has to do with public provision of education. Perhaps the biggest single industry that cities at least in the United States provide education. In a very interesting article that was done some time ago, a close friend of mine from memory, a Canadian at West, looked at why it was that the state of New York began to produce public education. And it was quite interesting. The claim in New York, this happened about 1850. Until then there was only private education in the state of New York. But the claim was that under private education, because the private schools had to charge, you had to pay a fee, there were some people who were not going to school because it was too expensive. Some children who could not go to school. And West went out and looked to see whether that was true. And he went right down to the records in each town and looked at the lists of the children and looked to see whether they were going to school or not. And it turned out everyone was going to school. There was no such thing as a child who wasn't going to school. And he then asked, well, how was it possible for everyone to go to school if some of the children were too poor for his private charity to pay in each case for the children to go to school? In fact, what happened is that the students who could pay all paid a little bit more so that the few children who couldn't afford it could also go to school. There isn't any evidence in other words that children could not go to school because it was too expensive. He then asked what was the point of having public education if everybody was already going to school? There was one group that was adamant, that was almost vehement in its support of public education. And you can guess who that might be. The private school teachers were the ones who wanted public education. Why did they want public education? Well, because with private schools they had to compete for students. And the competition was in quite strong. Secondly, under private education, teachers were answerable to parents. It was the parents of the children who were the monitors of the work that the teachers did. Once public education came in, who monitored the performance of the teachers? They set up a bureaucracy called the school board and it was stocked with teachers who were themselves the ones who decided whether or not this teacher would be hired, this teacher would be fired, who would be paid, how much, et cetera. Once public education was begun in New York, salaries for teachers went up quite a lot. And we observed that same distinction today in the United States. Public school teachers are paid much better than private school.  I don't know about in France but in the United States the strength of the teacher's lobby is absolutely enormous. One quarter of the delegates who nominated Jimmy Carter to run for president in 1980 were in fact teachers. One quarter. A piece of work that I did, some others who have been speaking at the seminars here have perhaps alluded to it on the stress by which public ownership came about. For over 200 years in the United States, the municipal fire department simply didn't exist. It was all done hard to get in. You had to pass the insurance company that insured the house would pay them for having put out the fire. Organizations financed themselves. Also the insurance companies bought the fire engines and the other capital equipment that the fire clubs needed. But these were purely voluntary private organizations. There was no governmental involvement whatsoever. Been on these private organizations to disorganize. They didn't do the job well. But in fact, when I went back and looked at the evidence was that from the politicians themselves, the disorganization that occurred at fires and there was always a lot of disorganization. There was looting and fighting and all kinds of behavior that was very unproductive to putting out fires. But the reason that that occurred is that the politicians refused to send the police to the fires. They told them not to go. The firemen then began to enforce their own rules and regulations to try to stop all these problems. When they would catch a looter or something like that at a fire and to enforce their own sorts of property rights, they just passed laws that put all these private fire departments out of existence. It just ended the system right then and there. If you go and look at the debates in the city hall and the state legislatures at the time that the private questions and the public fire departments were created, there were two principal groups that were in favor of public fire departments because they were the ones who were paying the bonuses to the firemen, paying the fees in other words, and also were the ones that were buying the fire engines. But the second group, and by far the most vociferous group, the most vehement group in favor of public fire departments was the firemen themselves because now they were paid to do what they used to do for nothing. The same people who had been in the private organizations were all taken into the public fire departments except before they weren't paid and now they were paid. And there was no requirement that they quit their other job to do it. In fact, they continued to do whatever job they had done before, but they were paid on top now by the city. So that was the plane, this movement to public ownership. It's very similar to what we saw in the case of public education. Once the labor group providing the service becomes fairly large and becomes fairly affected politically, they begin to bring political pressure to bear to have the ownership shifted from private hands to public hands and to have themselves then taken in to be part of the new public entity. They're paid more than they were before. They have an easier time of it. The level of service provided doesn't appear to increase in many cases as I've just explained. The productivity of the good or service produced appears to decline, but for the political group or for the labor group that's able to bring this political pressure to bear, results are quite favorable and how it relates to all of this. But I think I've gone on long enough, so let me stop it right there.


Don't swallow your gum, it will take almost a decade to digest. False. While gum is indigestible, it actually passes through you if you happen to swallow it. And it takes about two hours. Carrots are eye-superfood. This myth originated from World War II propaganda when the British Royal Air Force claimed that carrots helped pilots see through the night, which turned out to be false. The carrot story was told to cover up new technology they used to detect objects from afar. The vitamin A and beta-carotene and carrots are good for your eyes, but they've been way overhyped. Sugar makes you hyper. Wrong. The idea of sugar causing you to bounce off the wall has been a myth for ages. Even though a 1994 study declared that to be false, however, consuming large quantities of sugar could lead to ADHD-related symptoms over time.


Hello and welcome to the STM32L4 MOOC online training. My name is André Barata and this is the dedicated session for the DFSTM peripheral. DFSTM stands for Digital Filter for Sigma Delta Modulator and you can find the clear and detailed presentation on this peripheral on the theoretical slides posted down below. On this session we will solely focus on the practical aspects of implementing DFSTM on STM32QMX. In our hands-on we will demonstrate how to connect a single microphone and collect audio samples for this device. There is a microphone located on the bottom right corner of our L4 Discovery board as shown in the slides and it is connected through two wires to our microcontroller. The goal of this session is to learn how to connect our microphone physically, how to configure our DFSTM peripheral to convert the PDM signal to PCM signal, which is a type of data much easier to be transferred and processed by our microcontroller and how to generate and make use of the code generated by the STM32QMX. Let's start by explaining the physical connection of the microphone. On our L4 Discovery board there is an embedded microphone which is a MEMS based microphone and it's connected through two wires, audio clock and the audio data in. Those are respectively PA9 and PA7. PA7 is the line which transmits the data from the microphone to the microcontroller and PA9 delivers the clock source from DMCU to the microphone. The microphone needs a clock source from 1 MHz to 3.5 MHz to work properly. DFSTM role is to convert PDM format bitstream to PCM, which is a parallel data format with 24-bit resolution, much easier to be handled by the microcontroller. Our system is working at 80 MHz, the microphone input is clocked with 2 MHz and the output sampling frequency in PCM format will be 8 kHz. The maximum resolution of the output signal is 24 bits, being the rest of the 32 data which contains information about the channel configuration. As we just finished our theoretical presentation, let's now open STM32 Cubemix to start generating our code. With STM32 Cubemix open, our first step will be to click on New Project, we will type our part number STM32L476VG and then we will double click on the part number to start a new project. As you remember our microphone is connected to the microcontroller through the lines P7 and P9. To simplify the task of finding the correct pin, we may just type P7 which will alight the pin. We select it with the left button of the mouse and as we can see it is assigned to the DFSTM data in 2. So by going to the peripheral tree, we go to the DFSTM1 channel 2 and we will enable the mode DFSTM SPI channel 2 internal clock. So we will be using the internal clock provided by the MCU and the data will flow through the channel 2. P7 is assigned correctly, yet the clock line needs to be reassigned to the right pin. So by holding at the control key, we will relocate it to P9. This is just simply dragging it from its initial position to P9. On the clock configuration tab, by default we have 4 MHz MSI clock selected, but as we agreed to run this program at 80 MHz, we will need to change it. As you can see, we can't run it directly from MSI. Since for running at such high frequencies, we will need some PLL support. Fortunately, QBMX will handle all these changes for us. We just need to press OK and he will change everything to run with 80 MHz and this will happen through PLL. Let's have a look on the clock source for DFSTM. It is driven from the peripheral clock 2 as we were expecting. Let's go now to the biggest part of our configuration, which will happen on the configuration tab. On control session, we are going to select the DFSTM icon. And on the channel number 2, we should see the configuration SPI with rising edge and SPI clock should be internal SPI clock. No analog watchdog configuration will be preformed. More information about watchdog or any other parameter of the DFSTM can be found on the detailed theoretical presentation as they won't be covered during the hands-on session. We will press on apply and then we will go to the output clock window. In the output clock window, we will configure the clock source which goes to the microphone itself. As you recall, our system is running in 80 MHz and to achieve the 2 MHz for the microphone input clock, we need to set the divider to 40. This will be all for the clock parameters. And we will press apply to save the configuration. We have 4 filters available and they can be assigned to any given channel. In this session we will be using filter 0. We have 2 options when choosing which channels to be filtered. The regular channel selection or the injected channel selection. The difference between these 2 modes can be found on the theoretical slides once more. As we are just using one microphone, no switching between source signals is needed and we can just use the regular channel selection and assign it the filter to the channel too. We will select continuous mode as we want to have continuous conversions and the trigger to start conversion will be by software. The rest of the parameters will be handled after DMA configuration. The next step will be the configuration of the filter itself. The reason why we need filtering while using DFSTM is because we are converting the data from the PDM to PCM format, so over sampling needs to be considered. Here we can select the filter order. In our example we will be using sync3 filter type. Now we specify the output frequency. As we aim for 8kHz output frequency and our microphone is running at 2MHz we need to set FOSC to 250. So to wrap up 8kHz multiply by 250 will give us the 2MHz input clock source. The next parameter we will leave it as one. We will press apply to save the configuration and now let's go to the DMA configuration. With such high flow of information coming out of the DFSTM unit it is necessary to have support of the DMA to ensure smooth processing of the information. We will enable DMA from peripheral to memory and we will use standard priority as there are no other peripherals using DMA. Data length will be worth both sides and we will use memory increment. In mode we will use circular as we have continuous conversions of data on the buffer. We press apply and we will return to the filter zero configuration. We need to enable both fast mode and DMA mode. Fast mode is used as we just have one source of data, so there is no need to pre-fill the filter configuration each time. DMA mode is enabled as we are committing this filter to use DMA on its transfers. We will press apply and we just finish to configure the DFSTM peripheral for this specific application. As everything is configured we can just save and generate the code using system workbench for STM32 as our IDE. After the code is generated by STM32 Cubemix and our project is loaded on system workbench for STM32 we will open our main.c file stored inside of the source folder. On the main file you are supposed to see the initialization of all peripherals defined on STM32 Cubemix. In this specific case we can see the system clock configuration, DMA and the DFSTM unit which will be in focus on this session. As a first step we will initialize a buffer where we will store our data to be transferred through DMA. We start by defining a constant value which will be used as the length of the buffer. So we type define audio rack 1024. Then we proceed to initialize the buffer itself and it will be in 32 rack buff audio rack inside of the brackets. Although we are initializing a 32-bit long buffer it is important to note that each chunk of data stores 24 bits of significant audio data plus 8 less significant bits which are filled with data about the channel configuration. The next step will be to start the DFSTM peripheral using HAL functions. In this case HAL DFSTM filter regular start DMA. The four input parameters of this function are the handler to the DFSTM peripheral, the pointer to the buffer location and the size of the transfer. This function will start the acquisition of that in the DFSTM unit and as you recall in our configuration moment it will be triggered by software and mediated by DMA as the function's name suggests. We will proceed to compile and debug our code. On debug mode we will add to monitor our recorded buffer and if we would press resume and let it run for a while when we would pause we will see some value stored on it. If we would process and plot the data we would realize that the content does not look like an audio information and this is due to the fact that we did not treat our data and clear those 8 less significant bits from the PDM to PCM conversion. This is a common mistake when implementing DFSTM for the first time. As you might be guessing in the second part of our example we will implement a typical continuous reception of data where we will treat the data getting rid of those extra 8 bits. So let's start by creating an additional buffer which we will fill with treated audio content. We will initialize it just like we did before. So int, play buff with the same length. We also need to create two additional flags, one for complete and the other for half of complete reception of DMA transfers. When using DMA in circular buffer topology we will be able to make use of the recently transferred data, processed it and store it on the play buffer while in the second part of the DMA buffer is being filled in the meantime. So to make it clear whenever half of the buffer is completed we will treat this information while in the other half is being filled with data coming from the DFSTM unit. The DMA unit generates independent interrupts when reaching the complete and half complete size of the buffer. So to make use of this feature let's go to the STM32XXHALDFSTM.C file and we will copy the initialization of both interrupt service routines. Those can be found manually browsing the file or by simply pressing CTRL-F and search for the weak functions. We will copy them into the main file and we will set each flag inside of respective interrupt service routine. On the infinite loop we will proceed to check if any flag was set during the execution and in case if yes we will treat the content to be stored on the play buffer and logically clear the designated flag. To treat the content we just need to right shift the data 8 bits and this way we will get rid of the unnecessary data generated during the PDM to PCM conversion. We will apply this process to both halves of the buffer and then we will be ready to build and compile the project. We will start the application and add the play buffer to the monitor with expressions. If we would plot the data stored on it we would see a typical audio waveform. It is important to note that for this hands-on to be successful we need to apply an audible audio source so the microphone and DFSDME unit can clearly capture and convert the data. This will be all for this hands-on. Thank you for watching.


Do you have any belief in manifesting, that's what I believe? Yes. I get into so much trouble when I veer into that arena. So manifesting assumes that every single thing in your life you have because your thoughts created it. Correct. The thoughts create the realities, but I don't like this all encompassing, think it and have it. Think it and be it. It's like, yeah, well what about free will? And what about geopolitical unrest? Like who manifested COVID? Like whose fault is that?


I'm Monica from the Public Health Rebrand to Data Science program, and here is your Data Science tip for the day. Data Science Tip number three. If you choose to download data from an online portal that allows you to set criteria, don't do it on the fly. First, use the portal to study the variables and values in the data. Then make a data dictionary to guide your work. After all, you want to be able to replicate your extract. Want to excel in health data science? Follow my channel to learn more about my mentoring program for career advancement.


And also in the news, President Muammar Dubuari has welcomed the release of the abducted students of the Federal College of Forestry Mechanization in Kaduna State. Dubuari, in a statement issued by his spokesman, Garbashi, who also called for the release of the kidnapped students of Greenfield University and other people still in captivity. Gunmen had, in the early hours of March 11th, stormed the school and whisked away 29 students and released them 55 days after. The chairman of the parents' committee, Abdelay Usman, confirmed the release of students by the bandits to journalists, although he didn't state if any ransom was paid to secure the students' freedom. President Dubuari calls for steadfastness and security awareness on part of citizens and the law enforcement agencies and also deploys the increasing politicization of security in the country by opportunistic politicians. And don't forget to hit the notification button so you get notified about fresh news updates.


Also we could look at service. Now you'll notice that there's a lot of human beings that feel the importance of service. I could think of like social services, Catholic social services, United Way. I mean you can think about service agencies. They're there to serve. Or you can think of service in terms of doing volunteering service. I went through that myself. I was part of this thing called the holiday project where we went into nursing homes and hospitals to visit people that were shut in during the holidays. Thanksgiving, Christmas. And our slogan was, you are the gift. And we would just go in with service. It was extending and everything. And the interesting thing about service is that it's very helpful. It's a very helpful step at kind of getting you out of that egocentric me, myself, and my and I. And getting you into that sense of opening to share and extend with others. But also you start to realize that there's a lot of people that work in the social services. I was among them. I was, I worked in social services in a number of different ways. Community services and social services. But there's a number of people that really, I'll say, burn out. There's a very high burnout rate in social services. And that's kind of a clue that there's some ego mixed in. Because if you truly were in divine service, you would be in joy. You wouldn't burn out. You know, you wouldn't be like, I gotta take a vacation from all this social service. I've been helping people so much. I'm, I'm dead tired. And that also gives a hint that giving and receiving are the same. And so if you feel tired from serving, then you've been serving the ego. That fatigue and tiredness comes from following the ego. That when you're following the Holy Spirit, you are inspired. You are in the spirit. You are in the joy. Sometimes people will say that to me. They'll say, oh man, just looking at your like coming events page, I get tired of looking at that long thing.  I was at one of those Course in Miracles conference and Gary Renard during our presenters meeting, he was saying, oh, I just, I don't travel like David. That's just, you know, it was just like there was such a full travel schedule. Different towns, different days, different countries, just boom, boom flights and on and on and on and on, just packed in there for not just for a few months, just for years, packed, packed, packed full. Just pure delight for me. Absolutely, because it's, to me, it's involuntary. There was no individual doing it. It was just saying yes to the Spirit. What would you have me do? Where would you have me go? What would you have me say? And that was my prayer in the Spirit says, actually a lot. You're very willing. Well, here, try this on for about 20 years. Try that on, you know. And it was like, thank you. Thank you. Thank you for, for giving me the opportunity to teach what I would learn. It's not fatiguing at all to follow the Spirit. But if you have service ideas, like you're doing service for a future end, or you're doing service for somebody else, or you're doing service because you think the world is in need. The world's not in need. It's the sleeping mind that's in great need. The world's just a reflection of belief. So there's no real need in the world. I wasn't ever going to different countries because I think thought that those countries needed me. I was going there for my benefit, for my mind's benefit, to open up to the Holy Spirit. I used to read that in certain groups would say, well, so-and-so in the Middle East is really bad. Let's beam light, you know, to these poor people over in Ethiopia or the conflict in the Middle East and Syria. This is like, what's all that beaming light stuff about?  Yeah, the Middle East, that's where Khalil Gibran came from. You know, maybe you should open roomy, maybe you should open some of their books and soak in a little bit of that light before you beam it to these lacking countries and lacking cultures.  No, it's all for us. This is what the inspiration is. It's all for us to have a transformation of consciousness, to know the love and light ourselves. It's not about fixing anybody, changing anybody. So it takes a bit of washing away and a lot of the ideas of service, it's service for those that are less advantaged. Who set that up? Who set this world of advantaged and disadvantaged up? And who am I, or who is anyone, to point a finger at somebody and say, you are disadvantaged, but by God's grace, I'm going to come and help you out. I'm going to lend, reach down and lend helping hand. I remember this saying I used to hear, you know, pointing the finger at somebody and saying, but for the grace of God, there go I. And I used to think, how, Eric, to point the finger at somebody and say, but for the grace of God, there go I. I'm going to talk about superiority. You know, it's more like coming to a divine sense that your brothers and sisters are literally who you are and seeing them in fullness and wholeness and completion and saying, thanks to the grace of God, there go I. Thanks to the grace of God, I can see them as whole and complete. I can see a world without problems. I can see that as I am healed, the whole world is healed with me. I can see that if I am happy, the whole world must be happy, too, because there's no world apart from my mind. And who would we want to be a part of a system where you could be happy and others could be suffering or you could be enlightened and others could be unenlightened? You know, that's why we have our big dance party and we dance together. We circle dance, we dance, we wiggle, we're in the joy of the spirit together because we are the same and we're feeling the sameness of the spirit. The spirit unifies us. So to me, this is so, so important that we're letting go of these personal concepts. And in the end, all service is really self-service. We didn't get to watch that movie, Way of the Peaceful Warrior. But at the very end, Socrates, the teacher, he goes back there and there's nobody at the service station. It's suddenly a self-served station at the end of all this work with his teacher. I mean, the symbols in that are amazing. But you cannot burn out if you see that all service is capital S self, is Christ service, is service to yourself, is extending the love and light of Christ. And by extending it, it's the most natural experience you could ever have because you were created to extend love. And when you're extending love, you feel the joy of that original creation. So it's really beautiful and it's really simple, but the ego has just tried to make up a lot of other concepts that try to mix in and jet in to throw us off track. And forgiveness is always a gift to yourself. You're really never forgiving anybody else. You're just pulling and releasing these crazy concepts from your consciousness that don't belong there. And you're giving a gift to yourself and to everyone. But you're not like saying, well, God made me holy, so I have the power to forgive you for your sins. You know, it's forgive your brother for what he has not done. See the misperception in mind and release it from mind. That's really how you take the enemy, pluck the enemy out of your mind. Don't point the finger at the enemy as if they're in form because it just shows you that you believe in grievances if you're pointing fingers at enemies in form. It's cool. It's good stuff. It's healing. Ah, yeah.


A cost object is anything a manager might want to know the cost of. You can see some common examples on the slide, but the most common is the cost of a product. Product costs are one of the most important costs managers need to know. Knowing the cost of a product is a necessity to make sure that it's priced correctly, or if the company should increase or decrease production, or even discontinue the product altogether. Most companies use two different definitions of cost, total product cost and inventoryable product cost. The total cost is used for internal decision making. It includes all the costs of the value chain. Management needs to know total costs so it can price goods high enough to cover these costs and still make a normal profit. Inventoryable product costs, which are sometimes just called product costs, are only the costs incurred during the production stage of the value chain. Since inventoryable product costs include only costs incurred during production, all costs incurred in other stages of the value chain must be reported in the period in which they are incurred as expenses. Inventoryable product costs are required by GAP to be used for the cost of the asset, you know, inventory rather than total product costs. Because GAP will not allow total product cost to be reported on the balance sheet as an asset, the cost incurred in R&D, design, marketing, distribution and customer service are known as period costs. Period costs are reported on the income statement as expenses in the period in which they were incurred. They are often known as operating expenses or selling general and administrative expenses or SG&A for short. The product costs incurred in the production stage are not expensed when incurred. These costs are debited to an inventory account. The cost will remain as assets until the goods are sold, which could be in subsequent periods. And then we would record the cost as cost of goods sold and expense. So let's flash back to financial accounting for a moment. We learned that the cost of an asset is all of the costs incurred to get the asset ready for its intended purpose. That definition applies to inventory because it's an asset. So for merchandisers, the cost of the product, plus shipping and handling, et cetera, are included in the cost of the asset and debited to inventory. Manufacturers have to take raw materials and convert them into finished products. So the inventoryable product costs for manufacturers are direct materials, direct labor, and manufacturing overhead, which is an indirect cost. Direct costs are those that can be easily traced to a product. A car has four tires, so the cost of four tires is easily traced to a car. Indirect costs cannot easily be traced to a product. Because of this, we allocate indirect costs to products. Depreciation expense on a production facility isn't easily traceable to each finished good. So it is allocated to all of them. So direct materials and direct labor are direct costs, and manufacturing overhead is an indirect cost, which needs to be allocated to the products. You'll learn how to do that in future video podcasts. Finally, let's conclude this with a couple additional terms that you want to be familiar with. Prime costs include direct material and direct labor. Conversion costs include direct labor and manufacturing overhead. These are the costs incurred to convert materials into finished products. Make sure you don't make the mistake of adding prime costs plus conversion costs to get product costs. They can't be added together because direct labor would be added twice.


So, now let us see if we can understand how to follow solvent dynamics using ultrafast spectroscopy and as we are going to discuss by the end of this module this sometimes solvation can be ultra slow as well and first of slow study of solvation dynamics can give us some useful and interesting information. So, the way one studies solvation dynamics is you start from what we have discussed earlier you start with the molecule which has near 0 dipole moment and you excite it and the molecule should be such that there is a charge transfer in the excited state ultrafast charge transfer. So this is the situation in the ground state your molecule with no dipole moment and solvent molecules are oriented in whatever way they are oriented in around the solute molecule upon excitation charge transfer has to take place. Now this excitation takes place in ultrafast time scale at a second that is not enough time for the solvent molecules to reorient that is what I think Prajit was saying in the earlier module. Then given enough time the solvent dipoles would reorient around the 2 poles of the newly created solute dipole and you would get a happy situation like this and as we have discussed due to favorable dipole-dipole interaction you are going to get a stabilization of the excited state. Now see in case this molecule is fluorescent then what is the situation if you can record emission spectra at different times after excitation and we have discussed earlier in this course how one can do that one can do it either by gated emission or one can record steady state and time resolved data and construct the time resolved emission spectrum from there we are going to come back to that in a moment. Now the point is at time t equal to 0 you get emission at some particular maximal frequency as time passes there is going to be a red shift because the energy gap between the ground state and the excited state and the ground state would keep decreasing because of stabilization of the ground state and the fact that the corresponding excited state is of higher energy than the state that we actually excited the unsolvated state this is something we discussed in the previous module. So what you get is a time resolved stroke shift time dependent stroke shift TDSS as it called of the emission spectrum. So in this case one works with the maximum emission maximum of this time resolved emission spectra and from there we construct this solvent response function c of t which is given as nu at time t nu means as I said the maximum of emission spectrum at time t minus the emission maximum at time infinity time infinity means you do not really have to measure up to time infinity it means the time after which there is no further stroke shift and that is a contentious issue I will come back to that in a moment denominator is nu 0 minus nu infinity when nu 0 is the emission maximum at the instant of excitation nu infinity is what we have discussed already. Now see what are the problems associated with this how do you know nu 0 how do you know nu infinity that is what the problem is because if the lifetime is say in tens of nanoseconds lifetime of the excited state and solvation time is some 1 picosecond into picosecond then there is no problem because you would go from the higher energy unsolvated state to the completely stabilized state which will persist for a few nanoseconds. So you get nu infinity without hassle the problem arises if solvation time is comparable to the lifetime which we are going to show is the case in many cases then you do not know whether solvation is complete or not if solvation is not complete within the time scale of the measurement then nu infinity is not determined accurately that is one problem the second problem is how do you determine nu 0 the easiest way of doing it is well to feed the decays to multi exponential fitting functions and then construct the time resolved emission intensities by putting t equal to 0 now there is a problem with that the problem there is what is the time resolution of your experiment what is the instrument response function if you are going to do if you can excite with an atos second pulse atos again detection and do this experiment perhaps you will get the accurate value of nu 0 every time otherwise nu 0 is subject to errors associated with the full width of maximum of instrument response function. Now different people have proposed different ways of determining nu 0 all of them have some approach and some cons one way of determining nu 0 sometimes is people have considered the emission spectrum in non-polar solvents that may or may not be correct because even the ground state energy may not be exactly the same the energy gap between the ground state and the locally excited state may or may not be the same between polar and non-polar solvents as first approximation they are but not always another way that has been done is that the solvent has been frozen and you perform measurements at liquid nitrogen temperature this seems to yield a good result because when the solvent is frozen then there will be no reorientation so you look at the same excited state that you are going to excite anyway the only hesitation about that is that the polarity of the medium as we have seen for the mabn can be temperature dependent so no method is 100% full proof you have to work within whatever limitation it might have. Now let us come back to this fraction itself what does it denote nu at t-nu at infinity divided by nu at 0-nu at infinity what is the significance of this fraction okay nu 0-nu infinity what is that that is a total stoke shift what is nu t-nu infinity stoke shift that is yet to happen so this fraction c of t is the fraction of solvation that is yet to happen okay as has been discussed very nicely in this golden paper it has been cited I do not know how many thousand times the very famous paper by Bakshi, Oxtoby and Fleming 1987 what they have discussed is that due to linear response theory in the simplest case scenario you expect this c of t to decay exponential however most of the time you do not get a simple exponential decay you get something like this okay because there are different modes of solvation that are there it is not a very simple phenomenon as we are going to present very briefly about water there are different things that happen that is why you usually do not get there are cases in which you get single exponential as we are going to show but many times you do not get a simple single exponential decay of your solvent response function so generally c of t is fitted as a multi exponential function and each of the time constants is called a solvation time and the challenge is is it possible to assign each of the solvation time to some kind of a mode of motion of the solvent molecule okay. So let me show you some example of time dependence stoke shift data from our own lab here what do you expect if solvation takes place then you expect we have talked about what the signature of an excited state process is in this case solvation is taking place of the excited state so it is also an excited state process so you expect a fast decay in the blue end which corresponds to the in this case unsolvated locally excited state and you expect a rise time in the red end because that corresponds to the solvated excited state that is being formed so this is a typical kind of curve that you would expect okay. So what you do is you fit this kind of a time result fluorescence data to multi exponential function and you generate the intensity at some particular wave number by I nu bar SS multiplied by sum over I AI e to the power minus t by tau I divided by sum over I AI tau I it comes from the fact that what is this I nu bar SS that is the emission intensity at a particular wave number. Now emission intensity at a particular wave number is essentially integral of time resolved intensity from 0 to infinity it comes from there it is a standard integral which turns out to be sum over I AI tau I which is the total intensity and you get this kind of an expression. Now when you do this you are going to get time resolved emission intensity for different frequencies and when you plot them against frequency for different times you get this kind of a picture. This is an example of time resolved emission spectra and here we see from our lab an example of how C of t changes with time you can see it decays but it does not decays single exponentially one thing you can see we have not told you what the molecule here molecule is here does not really matter but one thing you can see is that the solvation is faster at least a long component of solvation is faster for methanol than for one propanol the reason is understandable one propanol is more viscous than methanol. So similarly there can be many other reasons many other factors that can influence solvation dynamics okay so to start with let us talk about solvation dynamics in non-equal solvents of course non-equal solvents can be classified in 2 parts apoptic solvent and alcohol in 1987 from ground flaming ground flaming group has made significant contribution to the field of solvation dynamics and not only flaming the students who later on went on to become independent researchers they have also done significant work so you can think flaming school comprising Kastner, Marancheli all these people have contributed big time the other players are Mark Berg well of course was a Bimann Berg, Chippos, Kankan, Bhattacharya these people have done a lot of work Ahmed Zuel towards after getting Nobel Prize got interested in the field of solvation dynamics will not really talk about his work here but you can read it and there are many groups in India which who have studied this Nancy Levinger has done significant work on solvation dynamics in things like reverse masses. So that is something that I leave for you to read yourselves it is a very interesting body of literature that has been created starting from say 1985 1987 until now new infinity has not been reached even now plenty of work is going on using solvation dynamics. So this particular work on the Kastner, Marancheli and flaming used this kind of a probe and let me show you the decays fluorescence decays in DMSO. So as you see in the blue end 570 nanometer you have a fast decay that almost gets over within 30 picosecond the red end of the spectrum 730 nanometer you see a distinct rise and here you see a long lived excited state that is the solvated state that is being formed okay. So this is the signature of solvation that we were talking about from there they constructed the time resolved emission spectrum and here in this early work they did not really bother working out C of t they simply plotted nu at time t against t as you understand you can rearrange that equation right and you can still get solvation time and these are the solvation parameters that they obtained. So as you see for acetonite trial linear response theory holds very nicely there is a single exponential decay associated with a 0.4 400 femtosecond decay sorry that is for acetonite trial for DMSO is the same thing but the decay is slower 3.1 picosecond. So you see acetonite trial and DMSO are they a protein what kind of solvents are they both are a protein solvents still there is an almost order of magnitude difference in solvation time that depends on the polarity of the solvent by enlarge so here you see a signature of polarity. Then when you go to nitrobenzene things get a little more complicated because you get double exponential nature of decay first one is 3.4 2.3 is I think calculated theoretically and second one is 6.3 picosecond. So if you look at nu bar infinity and you better look at nu 0 – nu infinity here also you see a lot of difference I think this is in 1000s of centimeter inverse or something this one is 1200 this is 770 this is 1080 so even the extent of stabilization not just dynamics depends on the solvent and even that has a story to tell from there the moment you go to protic solvents methanol has a 3.3 nanosecond single exponential solvation time butanol has a 66 this is nanosecond 3.3 picosecond 66 picosecond and 100 picosecond. So of course for butanol which is a more viscous solvent you get slower solvation times and due to viscosity different kinds of modes get decoupled and that is why you see not one but two different solvation times. This is only one example of solvation in a protic solvents mananchally especially has done a very thorough job I remember this JCP paper of 1994 or 1995 where I think there are several probes and like 30 40 solvents so of that paper I think 4 pages of that paper were just tables like this the small table. So exhaustive work has been done in non-equal solvents to understand the factors that contribute to solvation dynamics polarity, viscosity, hydrogen bonding everything matters. Having done this the next question that was asked is what about solvation dynamics in water. Now this is a very important and fundamental question that has been dealt with significantly after the report that I am going to show you because after all the entire life is based on water right. So understanding what happens in water is an interesting question that has persisted and water is not a simple liquid right. Sometimes figuratively we say something is as simple as water that is a completely wrong sentence scientifically whereas we should say as simple as hot water because in hot water some hydrogen bonds are broken. Water itself is an abnormal liquid as you all know it should not have been a liquid in the first place because H2S is a gas oxygen and sulfur oxygen is lighter the reason why water is liquid is hydrogen bond. So all the life processes are dependent on this extraordinary liquid that is water it is important to study solvation dynamics in water in many different forms. So the first report of this came in 1994 once again from Graham Fleming's group and the importance of this work is highlighted in the fact that it was published in Nature. Here similar TDSS studies were performed using Kumarin 343 so this has become one of the most used fluorescence probes after this study okay. So there are Kumarin 120 is 1, 343 is 1. So using this Fleming and coworkers got this kind of time resolved this is all femtosecond optical gating experiment okay. You can see first decay in the blue end rise in the red end and you can note the full scale of the experiment 2 picosecond. Of course this is a zoomed in picture they did do the experiment for much longer time and having done this they obtained the C of t and so how it evolves in time there is a lot of data in this we are only giving you an overview the expectation is that you are going to read this paper is extremely important should be read in detail I am not presenting that even the numbers here. So here this is the experimental time evolution of C of t and the other things that you see are theoretical fit and all that and this is how the oscillation takes place that is shown using molecular dynamics. So crux of the matter is that it is multi exponential in fact there is an initial Gaussian component it is not exponential all the way and what Fleming and coworkers did in this paper is that using experiment as well as molecular dynamics they could attribute the different solvation times to different kinds of motion of water the orientation liberation what is the meaning of liberation? Liberation means restricted rotation. So remember when we take water in isolation that is what we are used to thinking it is just HOH but water is not present in isolation in its liquid state as we know it is an associated liquid there are hydrogen bonds. So when a water molecule tries to rotate very often what happens is this hydrogen bond with the next water molecule hinders the rotation it cannot rotate all the way it comes back so that becomes a kind of an oscillator emotion which is identified as a low frequency vibration and motion it is not really rotating this kind of emotion back and forth. So that of course has energy that is much more than rotational motion but significantly less compared to vibrational motion in the next module we will actually show you the spectrum of water IR spectrum where you will see what kind of wave numbers are associated with this liberation. So this different modes of water how they contribute to solvation that is what was worked out in this paper please read it. So this was 1994 the next year the same group Fleming's group published a paper in Faraday Journal of Chemical Society Faraday Transaction. So what they showed the experiment they did there is that they took two probes C343 and C420 and they performed the experiment not in just water but in cyclo-dextrin in equest cyclo-dextrin solution. Cyclo-dextrin as we might have said earlier I do not remember if you have is a macro molecule that looks like an ice cream cup without a bottom and the reason why cyclo-dextrin is interesting is that the outer surface of cyclo-dextrin is polar the inner surface is non-polar so it can be used to solubilize non-polar solutes in water non-polar molecules in water it is used very frequently in drug formulation and all that. So in cyclo-dextrin Fleming's group found that solvation gets slowed down significantly this is a comparison of the time evolution of C of t between water and cyclo-dextrin and these are the associated solvation times. So you see that in addition to the picosecond component that was there first of all they did not observe a less than picosecond component this was a TCS physics experiment. And more importantly hundreds of picosecond component and in one case what they observed as a nanosecond component came in so you have slowing down of solvation by an order of magnitude and this paper sparked a series of work that has resulted in publication of I do not know how many thousand of paper half of my PhD thesis was inspired by this one paper. So the explanation initially was actually not correct what everybody thought was that you have bound water and free water so free water rotates quickly free water moves quickly and contributes to the first component of solvation bound water moves slowly and contributes to the slow component of solvation that is not quite right. As has been elucidated later mainly by the group of Professor Bhivan Bakshi there is a dynamic equilibrium remember I talked about dynamic exchange of solvents in the previous module or maybe in this module so what they showed is that the bound water is actually you can think frozen it does not participate in solvation as such however there is a dynamic exchange between bound and free water it is always the free water that is reorienting around the newly created diaper moment. But there is an exchange and if you remember your lessons from chemical kinetics if there is some equilibrium associated with that you have to take that into account the forward and backward rate constant and this exchange is what is associated with the slow component of water that is something that is that came out very nicely in this Nandi Bakshi theory and this is the cartoon representation of let us say a protein to which water is hydrogen bonded and here you have the regular network of free water there is a dynamic equilibrium between bound and free water when they considered that that is when they could arrive at this long solvation time. So if you look at the energies this is the situation for free water this is the situation for bound water there is a barrier crossing back and forth this K1 and K2 have to be considered when you build the kinetics scheme for solvation that is what causes slow solvation okay. So now let me take a detour with this from the main agenda of the course the title of our course is ultrafast processes now we have arrived at something that is not ultrafast which is not ultra slow maybe but definitely not ultra fast slow and the question to be asked is so what I mean why would we even be interested in slow solvation well slow solvation has in the last 20-22 years emerged as a marker of bound water as we have said and what has been shown later on is that you can actually use it by combining with confocal microscope capable of performing lifetime measurements FLIM this can give you an insight into really small volumes like never before. So in the next 3 minutes or 4 minutes let me present to you a brief summary of work done in one group that of frozen concovertage area in ISES in which they used a confocal FLIM setup fluorescence lifetime imaging microscopy setup when I say confocal what it essentially means is this that this is where your sample is right so the excitation light is focused on to a particular point in the sample focal point as you know cannot be less than lambda by 2 in diameter that is the diffraction limit and then there is a dichroic mirror that sends the this is the laser light this is the fluorescence light the dichroic mirror sends the fluorescence into this objective of the microscope after which the direction takes place. Now if you have work with sufficiently small concentrations you can look at single molecules by this technique so suppose you use an excitation wavelength of 400 nanometer what is the resolution you have 200 nanometer now suppose you use this microscope to study something like a cell what is the size of a cell microns you can see cells very easily under a not very sophisticated optical microscope yeah so the thing is since the cells are like 20,000 30,000 times larger than the resolution that we have in confocal microscopy you have the capability to look at not only the cell as a whole but also at different parts of the cell if you have a fluorescent probe that goes and binds to a mitochondria you can look at mitochondria selectively if there is something that goes and binds to some microtubules then you can look at microtubules selectively if there is something that will go and bind to say lysosome you will be able to see lysosome selectively and this technique has been used very effectively by groups like for example Yamuna Christians group who migrated from NCBS to UChicago few years ago gave a talk in our institute last year so one can look at different components of cell by using selectively by using confocal microscopy now if your confocal microscope is capable of measuring lifetimes you can measure lifetimes at different locations of the cell does not always have to be a cell of anything of that dimension and if your system is fitted with a grating and detector typically EMCCD then you can measure fluorescence spectrum as well in our setup we currently cannot do it so if you have an EMCCD and a grating combination as well as a lifetime measurement accessory FLIM then you can study solvation dynamics in different parts of the cell as well and that is what has been done by Vartacharia group this is one example what they did is they worked with CHO cell what is CHO Chinese hamster ovary the different there are several different cell lines that people work with this is Chinese hamster ovary. So there you see they use 2 dyes one is DCM this is DCM and the other is DAPI this is DAPI so DCM is known to localize in cytoplasm will not get into the detail of why that one can study DAPI is known to bind to nucleus. So what you see here is that if you look at the decays fluorescence decays they are definitely wavelength dependent and then if you record the emission spectrum as well you can get an idea of solvation times in different parts of the cell using DCM you can get the solvation time in cytoplasm using DAPI you can get the solvation time in nucleus using something else you can get a lifetime of something else and the good thing is here even if there is a distribution of DCM between the 2 different parts of the cell you can using confocal microscopy look at say cytoplasm once and record all your data there then look at say Golgi body another time record all your data in Golgi body. So coupling this time resolved emission spectroscopy with microscope gives us this very powerful technique of looking at dynamics in different parts of a very small volume like that of a cell and this is what a typical confocal image looks like and here looking at this image one can identify things like lipid droplets this is a nucleus this is a cytoplasm and recording fluorescence decays at different parts of the cell like this what Bhattacharya group was able to do is that they were able to work out the C of T is at different parts you see this is the decay of C of T in the nucleus this is the one in cytoplasm and this is what is there in lipid droplets. So if you look at the times in bulk what is it is about 1 picosecond in nucleus it is about 750 picosecond cytoplasm a little slower 1100 picosecond lipid droplets 3 times slower 3600 picosecond okay. And what has been proposed is that using these you can in fact later on this technique has been expanded to differentiate between say cancer cells and non-cancerous cells. So this is a way in which one can extend this time resolved ultrafast technique to think of applications in biological systems or even in micro heterogeneous materials okay. I think we will stop here today and next day we will talk about since we are talking about water now next day what we will do is we will talk a little more about water we are going to revise something that I think we did a little hurriedly any burnings work remember science 2003 science 2005 we are going to talk about that in little more detail and we will continue with the work from the same group in which they have shown how vibration energy gets redistributed into different modes of water. So today we talked about liberation and all we come back to that but from a different perspective in the next module and then after that have I talked about ESIPT at all in this course you are talking about x-ray intermolecular proton transfer then for the sake of historical accuracy we will do that since we are talking about photo acids anyway. Then what we will do is we will move over there is one debate that I would like to present if we get time and that is okay maybe we can do that as an extension of ESIPT ESPT then we will move over from molecules to nano clusters and then nano material.


So the Miami draw has just come out and there are some really interesting unseated players in the draw and some of the big names are going to have to play some of those players but let's go have a look at the players who are not playing in Miami this year. Okay so the players that are not playing on Drava she's pulled out Anissa Mova has also pulled out Benchich and Caviteva both pulling out of course not playing for the rest of the year because they're having babies. Mukava she just got surgery she's pulled out also Sevastova pulled out with injury. Sharif she's not going to play on Bondrusova also not playing in this one due to personal reasons so some big names there that will be missing in Miami. Okay all right so the top half of the draw the top section of the draw of course 32 seeds in this one everyone gets to buy in the first round starting with Svjontek world number one she gets to buy in the first round she'll take on either Frey or Georgie in the second round so not an easy match up there if it is Georgie in that second round then you got Gracheva taken on a qualifier winner of that will take on the number 26 seed Nozkova in the second round and Nozkovic Svjontek they played a lot this year already that could be a third round. Then you've got Pavlia Tchenkova getting a buy in the first round the 21st seed she'll take on either Frubitova or Rodgers in the second round then you got Vekic taken on Plushkova winner of that will take on the number 14 seed Alex Androva in the second round so pretty good section of the draw for Svjontek I mean yeah there's some danger players obviously Nozkova beats Svjontek at the first round open so that's the danger but she just beat her at Indian Wells in a straight set so there should be pretty manageable you think for Svjontek Plushkova is definitely dangerous down the bottom there Frubitova can do things Shelby Rodgers coming back for the first time in a while so look if you're a Svjontek fan you've got to be happy with that all right next section of the draw you've got Pelini the number 12 seed to buy in the first round she'll take on either a qualifier or a cannon in the second round so Pelini cannon great second round matchup potentially there then you've got another qualifier taken on Treveson winner of that will take on the number 20 seed Navarro in the second round then you've got the 31st seed Fernandez she'll take on either Maria or a qualifier in the second round then you got Buzkova taken on Zoo winner of that will take on the number five seed Pagula in the second round so another interesting section a pretty wide open section and Navarro's played well Pelini's played well Fernandez has been playing well at times Pagula needs some form so she's got to play well and might be a little bit under pressure cannon obviously a dangerous unceded player so really fun little section here and this section takes on Svjontek section so we'll see what happens with that as well all right next section of the draw we've got Coco Goff number three seed to buy in the first round she'll take in either a qualifier Kruger in the second round then you got Tormo versus Russe winner of that will take on the number 29 seed Kostuk in the second round then you got Garcia number 23 seed to buy in the first round she'll take on either Tomova or a qualifier in the second round and you got Chuck Eureto taken on Osaka winner of that will take on the number 15 seed Svetlina in the second round so Svetlina or Saka second round could be a thing you know Saka versus Garcia third round they've already played a couple times this year so that's gonna be really fun but again I mean Goff made the semifinals last week of Indian Wells I think she'd be pretty pretty happy with this draw I think she'd be too worried about this section at all all right next section of the draw you've got the number 10 seed Kazakina buying the first round she'll take on either a qualifier Martich in the second then you've got Stevens taken on Kerber great first round there winner of that will take on the number 19 seed Koseya in the second round then you've got the 30th seed Potapova she'll take on either a qualifier or Collins in the second round then you've got Avanessian taken on Andraeba that is Erika Andraeba winner of that will take on the number six seed on Schubert in the second round and again pretty open section you know Schubert needs some form Kazakina has been good this year there's obviously dangerous players like Collins and Kerber and the unseeded players Potapova played really well last week Steyer played really well here last year so a nice little section of course this half or this quarter of the draw will take on the Schviontek quarter of the draw so potentially we could be getting could be getting Schviontek taken on Goff in a semifinal we could be getting Schviontek taken on Jabur in a semifinal maybe even Schviontek versus Kazakina if you want to go with something a little bit different in the draw you probably go if you want to dream big you can probably go with Osaka versus Schviontek which I mean that's dreaming real big but hey it is a possibility that Schviontek can play Osaka in that semifinal all right next bottom half of the draw next section we've got number eight seed Sakurai she gets to buy in the first round she'll take on either Blinkova or Yuan in the second round then you got Sable taken on Zhong winner of that will take on the number 28 seed Yastremska in the second round then you got the 22nd seed Kallen Skyer will take on either Wong or Raducanu in the second round Raducanu and Kallen Skyer very fun matchup want to see what that looks like then you got two qualifiers playing each other winner of that match take on the number nine seed Ostapenko in the second round there's some fun names in this you know you've obviously got Raducanu as the unseeded player Sakurai's just played well last week Kallen Skyer has been good this year Ostapenko is always dangerous Stremska I mean this is probably the most stacked section with the seed because everyone's playing well in this section for the seed all right next section of the draw you got number 16 seed Kutumatoba to buy in the first round she'll take on either Wong or Baptist in the second round then you got Schneider taken on Venus Williams winner of that will take on the number 17 seed keys in the second round then you got the 25th seed Merton she'll take on either Bronzetti or a qualifier in the second round then you've got Dollarheide taken on another qualifier winner of that will take on the number four seed Rabakina in the second round again nice section of the draw for the top seed you know for the top seed of this section Rabakina I mean Dollarheide could be awkward in the second round Merton's played well last week but Rabakina's got a like a chance of getting through here I mean you've got to watch out for Venus obviously as well keys she could come good I don't know if I don't think Rabakina will really mind this section of the draw all right next section we've got the number seven seed Jung she will take on after getting a buy in the first round she'll take on either Bogdan or Sineacova in the second round then you got Stearns taken on Wong winner of that will take on the number 27 seed Azarenka in the second round then you got the number 24 seed Bolta she'll get a buy in the first round she'll take on either a qualifier or Brenda Fruvatova so the younger of the two sisters in the second round then you got Christian taken on Parry winner of that will take on the number 11 seed to Dajmaya in the second round so Jung hasn't been great since he is trying to open really need some form Miami being a little bit more like the Australian open court to speed she might be able to do something to Dajmaya also you know she's usually a slow court player so I don't know how well she's going to do here Bolta's been in good form and Azarenka you're always going to watch out for her and maybe keep an eye on Stearns because remember Stearns almost beat Savalinka last week in Indian Wells so she's got to be feeling pretty good about almost beating the world number two and the bottom section of the draw probably the most stacked with number 13 seed Sineacova she gets a buy in the first round she'll take on either puttenseva or buksa in the second round then you got Sarenka taken on Lynette winner of that will take on the number 18 seed Kragikova in the second round then you got the number 32 seed Kalanina getting a buy in the first round will take on either Boral or Wozniaki in the second round then you've got Halep versus Bedosa return to Simone Halep huge matchup winner to play Savalinka the down pursuit seed that is insane that section is insane now Bedosa has had injuries so let's see if she plays but if that plays true that is an insane section and a terrible draw for Savalinka to start with that is a nightmare Halep hasn't played for a while but she is still I think a very dangerous player of course you got to watch out for Savalinka you've got to watch out for Kragikova she can come good Samson overall so but Halep is the big one Halep is the one that we're all going to be focusing on Wozniaki as well got to keep an eye on her out of respect and last week did really well but Simone Halep is the one for me that you've got to keep an eye on and this section of the draw of course will take on the Rabakina section in a semifinal so Rabakina versus Savalinka semifinal if you want to go something a little bit different you could be going with Savalinka taking on Sakuri who's been really good this week of course you could go with Savalinka taking on Sopenko if you want to go a little bit more random or if you want Rabakina in the semis you can go Rabakina Jung Rabakina Kragikova Rabakina Azarenka maybe if you want to go something a little different but man that is the draw for Miami it's crazy that bottom part of the draw is insane everything else seems a little bit of average kind of I mean a little bit predictable maybe a little bit obvious but that bottom section with Halep Savalinka I mean come on that's insane who do you think's gonna win chat who is gonna win this one I'm gonna I'm gonna back Rabakina I think Rabakina if she's healthy might be able to win this whole thing if she's healthy Savalinka's draw though is a nightmare so I don't know if I could back her but maybe maybe Rabakina so if she's feeling pretty good especially with Savalinka in the semis Savalinka could lose and then Rabakina's road is a little bit easier but there it is that's the Miami draw for the ladies the men's draw comes out tomorrow