"If the NYSE, Nasdaq, Amex and OTC are trading 2 Billion shares a day or more , like today, thats $ 500 Million Dollars PER DAY. If there are 260 trading days a year. Thats about 130 Billion dollars a year. If volumes drop because of the tax. It is still 10s of Billions of dollars per year.

Thats real money for the US Treasury. Thats also an annual payment towards the next time Wall Street screws up and we have a black swan event that no one planned on."

"Learning in probabilistic models is often hampered by the general intractability of the normalization factor and its derivatives. Here we propose a new learning technique that obviates the need to compute an intractable normalization factor or sample from the equilibrium distribution of the model. This is achieved by establishing dynamics that would transform the observed data distribution into the model distribution, and then setting as the objective the minimization of the initial flow of probability away from the data distribution.…"

"In the rhizomatic model of learning, curriculum is not driven by predefined inputs from experts; it is constructed and negotiated in real time by the contributions of those engaged in the learning process. This community acts as the curriculum, spontaneously shaping, constructing, and reconstructing itself and the subject of its learning in the same way that the rhizome responds to changing environmental conditions…"

"Such dissolution of mathematics may be occurring already as evidenced by the proliferation and growth of fields, particularly since the middle of the last century, that have considerable mathematical content but whose fac- ulties and professional societies have little overlapping membership. When different fields sponsor different branches of mathematics, then the subfields may adopt the cultures of their sponsors, so the branches of mathematics eventually may come to disagree over acceptable notation, rigor, idiom, and terminology. Barriers among the branches of mathematics entail a large opportunity cost, so to speak, because possible collaborations and synergies may not be realized."

"In this paper we introduce a method for determining local interaction rules in animal swarms. The method is based on the assumption that the behavior of individuals in a swarm can be treated as a set of mechanistic rules.
The principal idea behind the technique is to vary parameters that define a set of hypothetical interactions to minimize the deviation between the forces estimated from observed animal trajectories and the forces resulting from the assumed rule set. We demonstrate the method by reconstructing the interaction rules from the trajectories produced by a computer simulation."

"It has long been known that scientific output proceeds on an exponential increase, or more properly, a logistic growth curve. The interplay between effort and discovery is clear, and the nature of the functional form has been thought to be due to many changes in the scientific process over time. Here I show a quantitative method for examining the ease of scientific progress, another necessary component in understanding scientific discovery. Using examples from three different scientific disciplines – mammalian species, chemical elements, and minor planets – I find the ease of discovery to conform to an exponential decay. In addition, I show how the pace of scientific discovery can be best understood as the outcome of both scientific output and ease of discovery."

"In the present work we introduce a novel multi-agent model with the aim to reproduce the dynamics of a double auction market at microscopic time scale through a faithful simulation of the matching mechanics in the limit order book. The model follows a "zero intelligence" approach where the actions of the traders are related to a stochastic variable, the market sentiment, which we define as a mixture of public and private information. The model, despite the parsimonious approach, is able to reproduce several empirical features of the high-frequency dynamics of the market microstructure not only related to the price movements but also to the deposition of the orders in the book."

"We describe a search for primitive trinomials of high degree and its interaction with the Great Internet Mersenne prime search (GIMPS). The search is complete for trinomials whose degree is the exponent of a Mersenne prime, for all 47 currently known Mersenne primes."

"Investigating the relation between the structure and behavior of complex biological networks often involves posing the following two questions: Is a hypothesized structure of a regulatory network consistent with the observed behavior? And can a proposed structure generate a desired behavior? Answering these questions presupposes that we are able to test the compatibility of network structure and behavior. We cast these questions into a parameter search problem for qualitative models of regulatory networks…. We develop a method based on symbolic model checking that avoids enumerating all possible parametrizations, and show that this method performs well on real biological problems, using the IRMA synthetic network and benchmark experimental data sets. We test the consistency between the IRMA network structure and the time-series data, and search for parameter modifications that would improve the robustness of the external control of the system behavior."

"All rolled into one big ball, the biggest thing to take away from this post is to find the job that will make you happy. These are all just things that I have that make me happy, so maybe they’ll help you find that great place to work. Because of all these reasons and probably some others I’ll think of after publishing this post, thoughtbot has my heart. Barring anything very unexpected, and until I’ve gotten sick of design, you’ll find me here at my desk inside thoughtbot HQ. I can only hope you have the same luxury or soon find a place that makes you just as happy."

"Software projects are displayed by Gource as an animated tree with the root directory of the project at its centre. Directories appear as branches with files as leaves. Developers can be seen working on the tree at the times they contributed to the project."

"As a web developer you really have no excuse for not knowing everything there is to know about URLs, there is just not that much to them. But, I have found that even experienced developers often have some glaring holes in their knowledge of URLs. So, I thought I would do a quick tour of everything that every developer should know about URLs. Strap yourself in – this won't take long ."

"Our findings suggest that in ravens, bystanders may console victims with whom they share a valuable relationship, thus alleviating the victims' post-conflict distress. Conversely victims may affiliate with bystanders after a conflict in order to reduce the likelihood of renewed aggression. These results stress the importance of relationship quality in determining the occurrence and function of post-conflict interactions, and show that ravens may be sensitive to the emotions of others."

"The occurrence of the nonzero leftmost digit, i.e., 1, 2, …, 9, of numbers from many real world sources is not uniformly distributed as one might naively expect, but instead, the nature favors smaller ones according to a logarithmic distribution, named Benford's law. We investigate three kinds of widely used physical statistics, i.e., the Boltzmann-Gibbs (BG) distribution, the Fermi-Dirac (FD) distribution, and the Bose-Einstein (BE) distribution, and find that the BG and FD distributions both fluctuate slightly in a periodic manner around the Benford distribution with respect to the temperature of the system, while the BE distribution conforms to it exactly whatever the temperature is. Thus the Benford's law seems to present a general pattern for physical statistics and might be even more fundamental and profound in nature. Furthermore, various elegant properties of Benford's law, especially the mantissa distribution of data sets, are discussed."

"As the study of information processing in living cells moves from individual pathways to complex regulatory networks, mathematical models and simulation become indispensable tools for analyzing the complex behavior of such networks and can provide deep insights into the functioning of cells. The dynamics of gene expression, for example, can be modeled with Boolean networks (BNs). These are mathematical models of low complexity, but have the advantage of being able to capture essential properties of gene-regulatory networks. However, current implementations of BNs only focus on different sub-aspects of this model and do not allow for a seamless integration into existing preprocessing pipelines. RESULTS: BoolNet efficiently integrates methods for synchronous, asynchronous and probabilistic BNs. This includes reconstructing networks from time series, generating random networks, robustness analysis via perturbation, Markov chain simulations [&c]"

"What is it that mathematicians accomplish?"

"Computational Complexity studies the power and limitations of efficient computation. So is efficient computation purely an abstract mathematical object or is it trying to model a real world phenomenon? I would argue the latter. Efficient computation occurs not just in computers but in biological systems, physical systems, chemical systems, economic systems and much more. Physics focuses on the "what", computational complexity on the "how"."

"The underlying reality of a succession of interbreeding populations is a vastly complicated network N. Since Darwin, species trees have been used as a simplified description of the relationships which summarize the overly complicated network N. Recent evidence of hybridization and lateral gene transfer, however, suggest that there are situations where trees are inadequate. Consequently it is important to determine properties that characterize networks closely related to N and possibly more complicated than trees but lacking the full complexity of N."

"Pay attention to the path the steepest descent takes until finding the optimum at x = 1 and y = 1. It is said that an evolution strategy would follow a similar path if its population could be infinite. Since, so far, there are no real computers with infinite memory, such assumption cannot be verified in the real world."

"This is a guide to the R programming language."

"Microbial ecosystems have been widely used in industrial production, but the inter-relationships of organisms within them haven't been completely clarified due to complex composition and structure of natural microbial ecosystems. So it is challenging for ecologists to get deep insights on how ecosystems function and interplay with surrounding environments. But the recent progresses in synthetic biology show that construction of artificial ecosystems where relationships of species are comparatively clear could help us further uncover the meadow of those tiny societies. By using two quorum-sensing signal transduction circuits, this research designed, simulated and constructed a synthetic ecosystem where various population dynamics formed by changing environmental factors."

"While some of the anti-fraud remedies of the securities laws still apply in 144A transactions, these have been watered down in recent years by Congressional action and judicial interpretation. In a series of opinions authored first by Justice Powell and then by Justice Kennedy, the Supreme Court has steadily scaled back the scope of the securities laws. Opinions by Justice Kennedy, in particular, limited the impact of anti-fraud protections as well as the ability of investors to sue gatekeepers who play a significant role in preparing offerings."

"Now folks, it's pretty revealing when lobbyists have become so accustomed to their privileged access and backroom dealings with politicians –as went on in regards to Cheney's energy discussions, and each of the Bush tax cuts drawn up by a secretive group of GOP without any sunlight (or bipartisansip), for example, and too much with the health care bill as well–that they don't even bother to hide their scorn for the public's views and their hopes for getting that back room deal to go their way. No wonder Wall Street honchos have been so brazenly arrogant about their "entitlement" to bonuses, their rights to continue proprietary trading and hedge funds and derivatives desks–"doing God's work" says Goldman CEO Blankfein–when they are merely running a casino market to strip as much gold off suckers as possible with their "financial innovations" like synthetic CDOs that made the market many times more volatile than "real" securitizations…"

"Since the microscope has no lenses, it does not magnify the images. Yet it is able to gain resolution just under two micrometers, and makes images that are about as clear as those made by a conventional 40X microscope. This is made possible by image-processing software. "We compensate for everything in the digital regime," says Ozcan. As light from the LED passes through a given type of cell, the light bends or diffracts in a characteristic way depending on the cell's size, shape, and refractive index. Data picked up by the light-sensing chip is carried to a cell phone for analysis. Ozcan has previously demonstrated running software on the phone that consults a library of diffraction signatures characteristic of particular cell types and bacteria to identify and count the cells in the sample."

"A recent study by researchers in Yale and published in PNAS shows that there are significant differences between the network topologies of living systems like E. coli and complex pieces of software such as the Linux Operating System."