Miracle-dz/UniFAR-FTUs huggingface dataset:
Controller Synthesis for Reward Collecting Markov Processes in Continuous Space

We propose and analyze a generic mathematical model for optimizing rewards in continuous-space, dynamic environments, called Reward Collecting Markov Processes. Our model is motivated by request-serving applications in robotics, where the objective is to control a dynamical system to respond to stochastically generated environment requests, while minimizing wait times. Our model departs from usual discounted reward Markov decision processes in that the reward function is not determined by the current state and action. Instead, a background process generates rewards whose values depend on the number of steps between generation and collection. For example, a reward is declared whenever there is a new request for a robot and the robot gets higher reward the sooner it is able to serve the request. A policy in this setting is a sequence of control actions which determines a (random) trajectory over the continuous state space. The reward achieved by the trajectory is the cumulative sum of all rewards obtained along the way in the finite horizon case and the long run average of all rewards in the infinite horizon case. We study both the finite horizon and infinite horizon problems for maximizing the expected (respectively, the long run average expected) collected reward. We characterize these problems as solutions to dynamic programs over an augmented hybrid space, which gives history-dependent optimal policies. Second, we provide a computational method for these problems which abstracts the continuous-space problem into a discrete-space collecting reward Markov decision process. Under assumptions of Lipschitz continuity of the Markov process and uniform bounds on the discounting, we show that we can bound the error in computing optimal solutions on the finite-state approximation. Finally, we provide a fixed point characterization of the optimal expected collected reward in the infinite case, and show how the fixed point can be obtained by value iteration.
Organization of suppression in receptive fields of neurons in cat visual cortex.

1. The response to an optimally oriented stimulus of both simple and complex cells in the cat's striate visual cortex (area 17) can be suppressed by the superposition of an orthogonally oriented drifting grating. This effect is referred to as cross-orientation suppression. We have examined the spatial organization and tuning characteristics of this suppressive effect with the use of extracellular recording techniques. 2. For a total of 75 neurons, we have measured the size of each cell's excitatory receptive field by use of rectangular patches of drifting sinusoidal gratings presented at the optimal orientation and spatial frequency. The length and width of these grating patches are varied independently. Receptive-field length and width are determined from the dimensions of the smallest grating patch required to elicit a maximal response. 3. The extent of the area from which cross-orientation suppression originates has been measured in an analogous manner. Each neuron is excited by a patch of drifting grating the same size as the receptive field. The response to this stimulus is modulated by a superimposed patch of grating having an orthogonal orientation. After selecting the spatial frequency that produces maximal suppression, the response of each cell is examined as a function of the length and width of the orthogonal (suppressive) grating patch. Results from 29 cells show that the dimensions of the orthogonal grating patch required to elicit maximal suppression are similar to, or smaller than, the dimensions of the excitatory receptive field. Thus cross-orientation suppression originates from within the receptive field. 4. For some cells the spatial frequency tuning of the suppressive effect is much broader than the spatial frequency tuning for excitation. In these cases it is possible to find a spatial frequency that produces suppression but not excitation. With the use of a suppressive stimulus having this spatial frequency, we examined the strength of suppression as a function of orientation for 11 cells. These tests show that suppression occurs at all orientations, including the preferred orientation for excitation. In some cases, suppression is somewhat stronger at the preferred orientation for excitation than at any other orientation. 5. For 12 cells we varied the relative spatial phase between the optimally oriented and orthogonal gratings. In all cases the magnitude of suppression is largely independent of the relative spatial phase. 6. For three binocular cells we examined whether the suppressive effect of a grating oriented orthogonal to the optimum could be mediated dichoptically. (ABSTRACT TRUNCATED AT 400 WORDS)
Soil Bacterial Communities Respond to Climate Changes in a Temperate Steppe

Climate warming and shifting precipitation regimes are affecting biodiversity and ecosystem functioning. Most studies have focused on the influence of warming and altered precipitation on macro-organisms, whereas the responses of soil microbial communities have been neglected. We studied the changes in the abundance, richness, and composition of the entire bacterial kingdom and 16 dominant bacterial phyla/classes in response to increased precipitation, warming, and their combination, by conducting a 5-year experiment in a steppe ecosystem in Inner Mongolia, China. Watering had a greater effect than warming on almost all the bacterial groups as indicated by changes in all the three attributes (abundance, richness, and composition). The 16 phyla/classes responded differentially to the experimental treatments, with Acidobacteria and Gamma-proteobacteria being the most sensitive. Stepwise regression analyses further revealed that climate changes altered the abundance and richness of bacterial groups primarily through direct routes (e.g., increasing soil water content), and changed the community composition through both direct and indirect routes (e.g., reducing soil total nitrogen content and increasing soil pH). The diverse responses of various bacterial groups could imply some potential shift in their ecosystem functions under climate changes; meanwhile, the indirect routes that are important in altering bacterial composition suggest that specific strategies (e.g., adding NH4NO3 to maintain soil nitrogen content and pH) could be adopted to maintain soil microbial composition under climate changes.
Dynamic Datum Transformations in Australia and New Zealand

Dynamic datums, which account for crustal dynamics, are widely used in Australia and New Zealand, although in many cases users may not be aware that they are using such a datum. The most widely-used global dynamic datums in Australia and New Zealand are the International Terrestrial Reference Frame (ITRF) and the World Geodetic System 1984 (WGS84). The use of WGS84 presents particular challenges, as it cannot be directly accessed at the sub-metre level by most spatial professionals. The relationship between WGS84 and ITRF is explored in detail, leading to recommendations on how users should deal with WGS84 datasets. New Zealand and Australia have taken different approaches to modelling the relationship between global dynamic datums and their local geodetic datums. Australia has calculated a set of local transformation parameters, which incorporate tectonic movements. New Zealand has adopted a set of global parameters, and uses a deformation model to account for crustal dynamics. As both countries seek to modernise their geodetic datums, the availability of simple yet accurate transformations will be critical to the success of the modernisation process. This paper outlines the options for dynamic datum transformations within a modernised datum, discussing the strengths and weaknesses of each approach. 뀀ഀȠ
POVERTY AND POLICY: EXPERIMENTS WITH A SAM-BASED CGE MODEL FOR GHANA

Ghana has often been regarded as one of the major success stories in sub-Saharan Africa in respect of the implementation of economic reform programmes during the 1980s and 1990s. However analyses of responses in terms of poverty reduction seem to indicate that structural adjustment may not be benefiting all segments of society. The aim of this paper is to carry out some counterfactual, numerical simulation experiments using variants of a stylised SAM-based CGE model, to ascertain possible effects on poverty of a range of revenueneutral redistributive policies. The analysis is based on a social accounting matrix (SAM) for Ghana compiled for the year 1993. This SAM not only has a detailed commodity and activity accounts within a structure in line with the recommendations of the 1993 SNA but it also has some quite detailed representations of factor and household accounts. The CGE model is a real-side, static model and therefore excludes the monetary and financial sectors. The experimental design follows in the tradition of Adelman and Robinson (1978) for Korea and Chia, Wahba and Whalley (1992) for the Cote d’Ivoire. However the model design and experiments are also influenced by recent exchange by De Maio, Stewart and van der Hoeven (1999) and Sahn, Dorosh and Younger(1999) with a view to examining the sensitivity of the experimental results to alternative specifications and closures within broadly similar, general SAM-based model structures.
So, You Want to Be a Lawyer? The Quest for Professional Status in a Changing Legal World

The quest for professional status remains a constant feature of early careers despite changes in opportunities for new lawyers. The narratives of early-career lawyers after two to three years of practice and again after nine to ten years, expose the realities of large law firm practice both before and during the financial crisis. Few lawyers had high expectations about becoming partners in large law firms. They accepted the reality of long hours of work and lack of control over their schedules and even their private lives, albeit with the hope of some future payoff. Money was important and obtaining “prestige” and “status” was equally so. While partnership at the firm was hardly realistic, lawyers still believed that they would at some time become what they imagined “real lawyers” to be— professionals with autonomy, responsibility, and most importantly control over their work. Many, somewhat belatedly, realized that joining a large law firm was neither a safety net nor a guaranteed path to success. The financial crisis has meant less work, leading more and more lawyers to become “performance casualties” in their firms. The focus on the bottom line means that a lot of the resources associated with professional socialization have been cut; large law firms are no longer a venue to learn how to become a leader, a client developer, or even a good case manager. Faced with diminishing work, the lucky associates have either retooled by obtaining additional degrees or changing substantive areas of practice, or moved to smaller firms where work is easier to obtain. Still, they remain committed to the goals of professional status. Firms that look to recruit and retain the best and the brightest would be wise to consider the quest for professional status as an important motivation for young lawyers. Debates about the transformation of the large law firm have been a consistent feature of legal scholarship for nearly two decades. Law review symposia1 and articles from law and the social sciences, books,2 and media
Posterior Corneal Curvature Assessment after Epi-LASIK for Myopia: Comparison of Orbscan II and Pentacam Imaging

Purpose To compare the changes in posterior corneal curvature using scanning slit topography (Orbscan II) and Scheimpflug imaging (Pentacam) before and after Epi-laser in situ keratomileusis (LASIK) for myopia. Methods In a prospective observational case-series study, 20 myopic patients having undergone Epi-LASIK were examined serially with two different devices, Orbscan II and Pentacam, preoperatively and one month postoperatively. Posterior central elevation (PCE) and posterior maximal elevation (PME) were compared between the two devices, and the changes in parameters after Epi-LASIK were analyzed using a difference map. Results All parameters (preoperative and postoperative PCE and preoperative and postoperative PME) that were measured using the Orbscan II were significantly greater compared to those of the Pentacam (for all p < 0.001). PCE and PME were significantly increased one month postoperatively in the Orbscan II measurements (p < 0.05) but were not significantly increased in the Pentacam measurements. Also, ΔPCE and ΔPME, in the difference map obtained by each serial scanning, were significantly greater in the Orbscan II measurements than with the Pentacam (p = 0.012, p = 0.016). Conclusions The Pentacam measurements displayed significantly reduced values in all parameters related to posterior corneal elevation compared to those of the Orbscan II. The Pentacam showed no significant change in posterior corneal curvature after Epi-LASIK, based on the difference map.
Cell Stiffness Is a Biomarker of the Metastatic Potential of Ovarian Cancer Cells

The metastatic potential of cells is an important parameter in the design of optimal strategies for the personalized treatment of cancer. Using atomic force microscopy (AFM), we show, consistent with previous studies conducted in other types of epithelial cancer, that ovarian cancer cells are generally softer and display lower intrinsic variability in cell stiffness than non-malignant ovarian epithelial cells. A detailed examination of highly invasive ovarian cancer cells (HEY A8) relative to their less invasive parental cells (HEY), demonstrates that deformability is also an accurate biomarker of metastatic potential. Comparative gene expression analyses indicate that the reduced stiffness of highly metastatic HEY A8 cells is associated with actin cytoskeleton remodeling and microscopic examination of actin fiber structure in these cell lines is consistent with this prediction. Our results indicate that cell stiffness may be a useful biomarker to evaluate the relative metastatic potential of ovarian and perhaps other types of cancer cells.
Essays on financial economics

This thesis consists of five chapters. The first chapter previews the analysis of the following three chapters. In the second chapter, my co-author and I provide new empirical evidence that the distribution of liquidity has a strong in-sample and out of- sample predictive power on intraday market volatility. To this end, we introduce a novel way of summarizing the relative depth provision in the whole limit order book. Our measure, global depth, considers the entire quoted depth and assigns weights decreasing with distance from the best quotes. We document that global depth outperforms alternative predictors of volatility, such as the bid-ask spread, standard depth variables, and measures of trading activity, in explaining the variations in market volatility. The third chapter, forthcoming in the Journal of Banking and Finance, investigates the effects of competition and signaling in a pure order driven market and examines the trading patterns of agents when walking through the book is not allowed. My co-author and I show that the variables capturing the cost of a large market order are not informative for an impatient trader under this market mechanism. We also document that the competition effect is not present only at the top of the book but persistent beyond the best quotes. Moreover, we show that institutional investors’ order submission strategies are characterized by only a few pieces of the limit order book information. The fourth chapter analyses the relationship between the firms’ disclosure decisions and the market expected value of default probabilities. I use option prices to estimate the option implied probability of default, whereas the level of disclosure is measured by a self-constructed voluntary disclosure index for the largest 85 U.S. bank holding companies. I provide evidence that the enhanced disclosure is followed by reduced market implied default probabilities in the subsequent year. This evidence suggests that by mitigating the information asymmetries between the bank management and their depositors and regulators, disclosure affects investors’ assessments of the riskiness of a bank. Finally, Chapter 5 sums up and points out directions for further work.
The Mondrian Kernel

We introduce the Mondrian kernel, a fast random feature approximation to the Laplace kernel. It is suitable for both batch and online learning, and admits a fast kernel-width-selection procedure as the random features can be re-used efficiently for all kernel widths. The features are constructed by sampling trees via a Mondrian process [Roy and Teh, 2009], and we highlight the connection to Mondrian forests [Lakshminarayanan et al., 2014], where trees are also sampled via a Mondrian process, but fit independently. This link provides a new insight into the relationship between kernel methods and random forests.
Vascular and Valvular Calcification in Chronic Peritoneal Dialysis Patients

Cardiovascular disease accounts over half of the total mortality in peritoneal dialysis (PD) patients. In addition, there is an increasing recognition of a high prevalence of vascular and valvular calcification that may contribute to the increased all-cause and cardiovascular mortality in the PD patients. Disturbed mineral metabolism in association with chronic kidney disease has been suggested as one of the major contributing factors to the increased vascular/valvular calcification in this population. In this paper, we provide an overview of the prevalence and importance of this complication in the PD patients. In addition, we review the contributing factors and some emerging mechanisms for this complication. Furthermore, we discuss some therapeutic strategies that may be useful in limiting the progression of vascular/valvular calcification in the PD population.
Formation of Disk Galaxies: Feedback and the Angular Momentum Problem

When only cooling processes are included, smoothed-particle hydrodynamical (SPH) simulations of galaxy formation in a cold dark matter hierarchical clustering scenario consistently produce collapsed objects that are deficient in angular momentum by a factor of about 25 relative to the disks of observed spiral galaxies. It is widely hoped that proper allowance for star formation feedback effects will resolve this discrepancy. We explore and compare the effects of including two different types of feedback event: uniform reheating of the entire universe to 5 × 105 K at a redshift of z ~ 6, and gas blowout from pregalactic gas clouds comparable to present-day dwarf galaxies at a somewhat lower redshift. We find that blowout is far more successful than early reheating, and that it may even be sufficient to solve the angular momentum problem. We see indications that the remaining angular momentum deficit (a factor of 5 in the blowout models) is due to current limitations in the numerical method (SPH) used in our and other authors' work. Our most successful models distinguish themselves by the fact that a large fraction of the gas is accreted very gradually, in a cooling flow from a surrounding hot phase rather than by mergers of massive cold clumps.
Pornography, Rape, and the Internet

The arrival of the internet caused a large decline in both the pecuniary and non-pecuniary costs of accessing pornography. Using state-level panel data from 1998-2003, I find that the arrival of the internet was associated with a reduction in rape incidence. While the internet is obviously used for many purposes other than pornography, it is notable that growth in internet usage had no apparent effect on other crimes. Moreover, when I disaggregate the rape data by offender age, I find that the effect of the internet on rape is concentrated among those for whom the internet-induced fall in the non-pecuniary price of pornography was the largest ‐ men ages 15-19, who typically live with their parents. These results, which suggest that pornography and rape are substitutes, are in contrast with previous laboratory studies, most of which do not allow for potential substitutability between pornography and rape.
Genome sequencing and comparative analysis of Saccharomyces cerevisiae strain YJM789

We sequenced the genome of Saccharomyces cerevisiae strain YJM789, which was derived from a yeast isolated from the lung of an AIDS patient with pneumonia. The strain is used for studies of fungal infections and quantitative genetics because of its extensive phenotypic differences to the laboratory reference strain, including growth at high temperature and deadly virulence in mouse models. Here we show that the ≈12-Mb genome of YJM789 contains ≈60,000 SNPs and ≈6,000 indels with respect to the reference S288c genome, leading to protein polymorphisms with a few known cases of phenotypic changes. Several ORFs are found to be unique to YJM789, some of which might have been acquired through horizontal transfer. Localized regions of high polymorphism density are scattered over the genome, in some cases spanning multiple ORFs and in others concentrated within single genes. The sequence of YJM789 contains clues to pathogenicity and spurs the development of more powerful approaches to dissecting the genetic basis of complex hereditary traits.
Options Pricing Via Statistical Learning Techniques: The Support Vector Regression Approach

We explore the pricing performance of Support Vector Regression for pricing S&P 500 index call options. Support Vector Regression is a novel nonparametric methodology that has been developed in the context of statistical learning theory and until now it has been practically neglected in financial econometric applications. This new method is compared with Parametric Options Pricing Models using standard implied parameters and parameters derived via Deterministic Volatility Functions. The empirical analysis has shown promising results for the Support Vector Regression approach.
Innovation and hybridization: Managing the introduction of lean production into Volvo do Brazil

Although the influential group located at the Massachusetts Institute of Technology have argued that “teamwork” is at the heart of the lean factory; more recent works have identified “innovation” as the major driver “of growth in free market economies”. Others have gone further in suggesting that the global business environment has so fundamentally changed that it is the demands of the knowledge economy that are the crucial challenge to global organisations. They identify “tomorrow's winners” as those organisations able to “search out and mobilize untapped pockets of technology and market intelligence” to add significant value to their operations. In this paper two of these “global practices” are analyzed in terms of the management of their introduction at the Curitiba plant of Volvo do Brazil. First, the development of team‐based forms of work organization is analyzed within the context of the changing nature of patterns of global human resource development. Secondly, the increasing utilization of lean production techniques is located within the context of the development of a global production strategy within the Volvo Truck Company. This paper attempts an understanding of the nature of the relationship between team‐based forms of work and lean production within a framework which recognizes the increasing importance of organisations attached to innovation – in the sense of a hybrid system of learning from the best practice of other organisations. In doing so it will assess how far we can claim the presence of a new production paradigm being developed within the plant.