cssi/SciSciGPT-SciSciNet huggingface dataset:
Optimal transcriptional regulation of cellular responses to sudden environmental shifts

Cellular responses to sudden changes in their environment require prompt expression of the correct levels of the appropriate enzymes. These enzymes are typically regulated by transcription factors that sense the presence of inducers and control gene expression for the duration of the response. The specific choice of regulatory strategy depends on the characteristics of each cell response, with the pattern of gene expression dictated by parameters such as the affinity of the transcription factor to its binding sites and the strength of the promoters it regulates. Although much is known about how gene regulation determines the dynamics of cell responses, we still lack a framework to understand how the many different regulatory strategies evolved in natural systems relate to the constraints imposed by the selective pressures acting in each particular case. Here, we analyze a dynamical model of a cell response where expression of a transcriptionally repressed enzyme is induced by a sudden exposure to its substrate. We identify strategies of gene regulation that optimize the response for different types of selective pressures, which we define as a set of costs associated with substrate, enzyme and repressor intracellular concentrations during the response. We find that regulated responses happen within a defined region in the parameter space. While responses to costly (toxic) substrates favor the usage of strongly self-regulated repressors, responses where expression of enzyme is more costly than its substrate favor the usage of constitutively expressed repressors. There is only a very narrow range of selective pressures that would favor weakly self-regulated repressors. This framework can be used to infer which costs and benefits are most critical in the evolution of natural examples of cellular responses, and to predict how a response can optimize its regulation when transported to a new environment with different demands.
A Straight-Forward Method of Moments Procedure to Solve the Time Domain Integral Equation Applicable to PEC Bodies via Triangular Patch Modeling

In this work, a simple and straight-forward method of moments solution (MOM) procedure is presented to obtain the induced current distribution on an arbitrarily-shaped conducting body illuminated by a Gaussian plane wave directly in the time domain using a patch modeling approach. The method presented in this work, besides being stable, is also capable of handling multiple excitation pulses of varying frequency content incident from different directions in a trivial manner. The method utilizes standard Rao-Wilton-Glisson (RWG) functions and simple triangular functions for the space and time variables, respectively, for both expansion and testing. The method adopts conventional MOM and requires no further manipulation invariably needed in standard time-marching methods. The moment matrix generated via this scheme is a block-wise Toeplitz matrix and, hence, the solution is extremely efficient. The method is validated by comparing the results with the data obtained from the frequency domain solution. Several simple and complex numerical results are presented to validate the procedure.
HST STIS Ultraviolet Spectral Evidence of Outflow in Extreme Narrow-line Seyfert 1 Galaxies: II. Modeling and Interpretation

We present modeling to explore the conditions of the broad-line emitting gas in two extreme Narrow-line Seyfert 1 galaxies, using the observational results described in the first paper of this series. Photoionization modeling using Cloudy was conducted for the broad, blueshifted wind lines and the narrow, symmetric, rest-wavelength-centered disk lines separately. A broad range of physical conditions were explored for the wind component, and a figure of merit was used to quantitatively evaluate the simulation results. Of the three minima in the figure-of-merit parameter space, we favor the solution characterized by an X-ray weak continuum, elevated abundances, a small column density (log(N_H)\approx 21.4), relatively high ionization parameter (log(U)\approx -1.2 - -0.2), a wide range of densities (log(n)\approx 7 - 11), and a covering fraction of ~0.15. The presence of low-ionization emission lines implies the disk component is optically thick to the continuum, and the SiIII]/CIII] ratio implies a density of 10^10 - 10^10.25 cm^-3. A low ionization parameter (log(U)=-3) is inferred for the intermediate-ionization lines, unless the continuum is ``filtered'' through the wind before illuminating the intermediate-line emitting gas, in which case log(U)=-2.1. The location of the emission regions was inferred from the photoionization modeling and a simple ``toy'' dynamical model. A large black hole mass (1.3 x 10^8 M_\odot) radiating at 11% of the Eddington luminosity is consistent with the kinematics of both the disk and wind lines, and an emission radius of ~10^4 R_S is inferred for both. We compare these results with previous work and discuss implications.
GzScenic: Automatic Scene Generation for Gazebo Simulator

Testing robotic and cyberphysical systems in simulation require specifications of the simulated environments (i.e., scenes). The Scenic domain-specific language provides a high-level probabilistic programming language that allows users to specify scenarios for simulation. Scenic automatically generates concrete scenes that can be rendered by simulators. However, Scenic is mainly designed for autonomous vehicle simulation and does not support the most popular general-purpose simulator: Gazebo. In this work, we present GzScenic; a tool that automatically generates scenes for simulation in Gazebo. GzScenic automatically generates both the models required for running Scenic on the scenarios, and the models that Gazebo requires for running the simulation.
Lamellar Architecture Affords Salt Cocrystals with Tunable Stoichiometry

Cocrystals typically display packing motifs distinct from their constituent components; this is a natural result of the new interactions being introduced disrupting those present in the pure compon...
Inorganic Dust Exposure During Military Service as a Predictor of Rheumatoid Arthritis and Other Autoimmune Conditions.

Author(s): Ying, David; Schmajuk, Gabriela; Trupin, Laura; Blanc, Paul D | Abstract: ObjectiveRheumatoid arthritis (RA) and other autoimmune (AI) conditions are associated with inorganic dust exposure. Many military activities are likely to entail inorganic dust exposures. We wished to identify associations between prior military dust exposure and RA and other AI conditions.MethodsWe studied persons from a roster of Army, Navy, Air Force, or Marine Corps personnel who had served in Operation Enduring Freedom and Operations Iraqi Freedom and New Dawn. We linked military occupational codes to a job exposure matrix assigning dust exposure likelihood. We used the Veterans Affairs Health Care System (VAHCS) electronic health care records to identify cases of RA, systemic lupus erythematosus (SLE), systemic sclerosis (SSc), vasculitis, and inflammatory myositis. Generalized estimating equations modeled risk of RA and other AI conditions associated with dust exposure, taking into account military service branch, age at first VAHCS encounter, sex, race/ethnicity, smoking status, and years of military service.ResultsOf 438 086 veterans (68% ever-smokers), 44% were classified with likely or somewhat likely dust exposure. Cases included 1139 cases with RA, 467 cases with SLE, and 180 cases with other AI diseases (SSc, vasculitis, or inflammatory myositis). Military dust exposure was associated with increased odds of RA (odds ratio [OR] = 1.10; 95% confidence interval [CI] = 1.003-1.20) and increased odds of SSc, vasculitis, or inflammatory myositis (OR = 1.23; 95% CI = 1.14-1.34) but was protective for SLE (OR = 0.81; 95% CI = 0.76-0.88).ConclusionDust exposure during past military service comprises an occupational and environmental risk factor for RA and other AI diseases. This is potentially relevant for prevention activities.
Pathogenic ubiquitination of GSDMB inhibits NK cell bactericidal functions

Gasdermin B (GSDMB) belongs to a large family of pore-forming cytolysins that execute inflammatory cell death programs. While genetic studies have linked GSDMB polymorphisms to human disease, its function in the immunological response to pathogens remains poorly understood. Here, we report a dynamic host-pathogen conflict between GSDMB and the IpaH7.8 effector protein secreted by enteroinvasive Shigella flexneri. We show that IpaH7.8 ubiquitinates and targets GSDMB for 26S proteasome destruction. This virulence strategy protects Shigella from the bacteriocidic activity of natural killer cells by suppressing granzyme-A-mediated activation of GSDMB. In contrast to the canonical function of most gasdermin family members, GSDMB does not inhibit Shigella by lysing host cells. Rather, it exhibits direct microbiocidal activity through recognition of phospholipids found on Gram-negative bacterial membranes. These findings place GSDMB as a central executioner of intracellular bacterial killing and reveal a mechanism employed by pathogens to counteract this host defense system.
Endoscopic Third Ventriculostomy With "Rescue" Fourth Ventriculocisternostomy: 2-Dimensional Operative Video.

This case of endoscopic third ventriculostomy (ETV) and flexible endoscopy for lysis of fourth ventricle adhesions for obstructive hydrocephalus illustrates a key anatomical variant (anastomosis of posterior communicating arteries) that increases the difficulty of ETV and should be recognized preoperatively. The video further demonstrates flexible endoscopy for lysis of a fourth ventricular web and excellent third and fourth ventricular anatomy. This patient presented with normal pressure hydrocephalus-like symptoms and magnetic resonance imaging suggestive of a fourth ventricular outflow obstruction. An ETV would be an ideal intervention with a high chance of success1 and avoiding a ventriculoperitoneal shunt or a more invasive suboccipital craniectomy for fourth ventricle exploration; however, variant anatomy and resultant medialization of the bilateral posterior communicating arteries put their location directly beneath the tuber cinereum. After discussing the risks and benefits of the proposed procedure, the patient consented to proceeding with the surgery. Patient is not identifiable either by clinical vignette or through this operative video, which is entirely intraventricular. The care rendered was standard (nonexperimental). The patient did sign consent for filming and production of the educational video submitted. Here, we present operative video from our ETV, demonstrating an inability to confirm adequate fenestration and subsequent flexible endoscopy for fourth ventriculocisternostomy.
The Study’s TBLE Distortion-Analysis Protocol for Economic-Efficiency Analysis

This chapter delineates and argues for the ex ante economic efficiency of the “distortion-analysis” protocol this study uses to assess the economic efficiency of choices. This protocol has three distinctive features. First, it instructs the analyst to consider the impact of the choice whose economic efficiency is at issue on the magnitudes of many categories of economic inefficiency that conventional economic-efficiency analyses ignore (including the economic inefficiency generated by resource allocations between alternative quality-or-variety-increasing-investment [QV-investment]-creating uses, between alternative production-process-research [PPR]-executing uses, among alternative unit-output-producing, QV-investment-creating, and PPR-executing uses, and among alternative final consumers). Second, it instructs the analyst to predict the impact of the choice under review on many individual categories of economic inefficiency (resource misallocation) by estimating the choice’s impact on the amount of resources devoted to the associated category of resource allocations, by estimating the profits/losses that would be generated by the choice-elicited/deterred resource allocation, by developing formulas for the difference between the profits yielded by and the economic efficiency of (the “distortion” in the profits yielded by) the individual exemplars of a relevant category of resource allocations, by estimating the post-choice magnitudes of the parameters in those formulas (primarily Pareto imperfections), and by combining the conclusions of the preceding analyses. Third, the protocol contains a subprotocol for determining the ex ante economic efficiency of doing any economic-efficiency-analysis-relevant work (which takes account not only of the direct allocative cost of such efforts but also of the allocative cost of the government’s financing such efforts) and instructs the analyst to do all that work but only that work whose performance is ex ante economically efficient.
Crevice Repassivation Potentials for Alloy 22 in Simulated Concentrated Ground Waters

The resistance of Alloy 22 (N06022) to localized corrosion, mainly crevice corrosion, has been extensively investigated in the last few years. However, the behavior of Alloy 22 in concentrated aqueous solutions that may simulate concentrated ground waters was not fully understood. Systematic electrochemical tests using cyclic potentiodynamic polarization as well as the Tsujikawa-Hisamatsu electrochemical method were performed to determine the crevice corrosion susceptibility of Alloy 22 in simulated concentrated water (SCW), simulated acidified water (SAW) and basic saturated water (BSW). Results show that Alloy 22 is immune to crevice corrosion in SCW and SAW but may suffer crevice corrosion initiation in BSW. Results also show that in a naturally aerated environment, the corrosion potential would never reach the critical potential for crevice corrosion initiation.
Analyzing tensor power method dynamics in overcomplete regime

We present a novel analysis of the dynamics of tensor power iterations in the overcomplete regime where the tensor CP rank is larger than the input dimension. Finding the CP decomposition of an overcomplete tensor is NP-hard in general. We consider the case where the tensor components are randomly drawn, and show that the simple power iteration recovers the components with bounded error under mild initialization conditions. We apply our analysis to unsupervised learning of latent variable models, such as multiview mixture models and spherical Gaussian mixtures. Given the third order moment tensor, we learn the parameters using tensor power iterations. We prove it can correctly learn the model parameters when the number of hidden components k is much larger than the data dimension d, up to k = o(d1.5). We initialize the power iterations with data samples and prove its success under mild conditions on the signal-to-noise ratio of the samples. Our analysis significantly expands the class of latent variable models where spectral methods are applicable. Our analysis also deals with noise in the input tensor leading to sample complexity result in the application to learning latent variable models.
Enantioselective α-Trifluoromethylation of Aldehydes via Photoredox Organocatalysis

The first enantioselective, organocatalytic α-trifluoromethylation and α-perfluoroalkylation of aldehydes have been accomplished using a readily available iridium photocatalyst and a chiral imidazolidinone catalyst. A range of α-trifluoromethyl and α-perfluoroalkyl aldehydes were obtained from commercially available perfluoroalkyl halides with high efficiency and enantioselectivity. The resulting α-trifluoromethyl aldehydes were subsequently shown to be versatile precursors for the construction of a variety of enantioenriched trifluoromethylated building blocks.
Computer Simulation and Animation Environment for Control Education

Abstract Today’s advanced microcomputers offer extremely fast processing speed and vibrant high-resolution color graphics capabilities at affordable cost. By using carefully developed courseware (software used for coursework), these technologies can be used to strengthen engineering course delivery and provide laboratory innovation. This paper describes an interactive computer visualization environment in which real-time simulation and animation (RTSA) is used to significantly enhance control engineering curricula. Presented is the potential impact of the proposed environment on control engineering education with illustrative examples. The roles of this new interactive computer learning experience in control engineering curriculum are two-fold: 1) To provide a new method for delivering classroom material whereby real-world control system engineering concepts are introduced via interative RTSA, and 2) To provide an opportunity innovative laboratory assignments where students can analyze, design and modify control engineering systems via interactive RTSA. Positive acceptance and reactions have been widely received from users and audiences of RTSA programs which were incorporated in research projects and control curricula at Oakland University.
The Piperazine Space in Isocyanide-based MCR Chemistry

Piperazines and its congeners, (di)keto piperazines are valuable tools in drug discovery, providing a natural path for the process peptide > peptidomimetic > small molecule also called depeptisation. Moreover, they can provide molecular probes to understand molecular pathways for diseases of unmet medical need. However, in order to better understand the design of such value added compounds, the detailed understanding of scope and limitation of their synthesis as well as their 3D structures and associated physicochemical properties is indispensables. Isocyanide multicomponent reaction (MCR) chemistry provides a prime tool for entering the chemical space of (di)(keto)piperazines since not less then 20 different ways exist to access a diversity of related scaffolds.
A Race to Develop: A Competing Risk Examination of the Pattern and Timing of Land Development in an Exurban County

Abstract: Rural-urban fringe counties (i.e. counties adjacent to other counties with large and growing urban centers) often experience intense development pressure as a result of urban growth and expansion. While growth-initiated development can take many forms, the majority of the development that occurs in these exurban counties is in the form of single-family residential dwellings. Moreover, it is in the form of subdivision developments that range in size from very small two and three lot minor subdivisions to massive multi-phase major subdivisions with hundreds of lots and numerous amenities. In this paper, we focus on the land development patterns in Carroll County, MD, an urban-fringe county in the Baltimore-Washington D.C. metro region. The purpose of this paper is to explore whether a basic set of factors, both constant and time-dependent and acting at different spatial scales, can explain the timing and location of major versus minor subdivision developments in Carroll County. Using a micro-level panel of land parcel conversion, historical land records for subdivision development and ArcGIS software a new dataset was created that traces the entire history of the subdivision process in the county. Datasets were also created that trace the history of land preservation so that we could control for official open space and its interaction with the decision to subdivide through time. Using these data and a number of land use variables created from them from 1993-2007, we apply a competing risks duration model to analyze which factors affect major versus minor subdivision development. Visual inspection as well as a descriptive analysis of a series of landscape metrics based on distance from the metropolitan center reveals a different pattern outcome for small versus large subdivisions with larger developments following more closely to the predictions of the urban economic model. Empirically, we find further evidence that the factors affecting the timing of minor versus major subdivision developments are indeed different. Distance and access to road networks have less of an effect on minor over major developments, while surrounding preservation and the option to preserve have less of an effect on major subdivisions. To make the risk comparison relevant and to focus on areas that have experienced the most fragmentation as a result of residential land conversion as well as the most policy attention, we restrict our analysis to parcels located in minimum density zoning districts.
The Impact of Irrigation Capital Subsidies on Common-Pool Groundwater Use and Depletion: Results for Western Kansas

We examine the effects of irrigation technology subsidies using a model of inter-temporal common pool groundwater use with substitutable technology and declining yields from groundwater stocks, where pumping cost and stock externalities arise from the common property problem. We develop and simulate an optimal control analytical model parameterized for Sheridan County, Kansas, overlying the Ogallala aquifer. We contrast competitive and optimal allocations and account for endogenous and time-varying irrigation capital on water use and groundwater stock. In our analysis, we account for the labor-savings from improved irrigation technologies. We find that in the absence of policy intervention, the competitive solution yields an early period with underinvestment in efficiency-improving irrigation technology relative to the socially efficient solution, followed by a period of overinvestment. This suggests a potential role for irrigation capital subsidies to improve welfare over certain ranges of the state variables. In contrast to previous work, we find evidence that significant returns may be achieved from policy intervention. We simulate a policy scenario where an irrigation technology subsidy is implemented to explore whether such a program can capture significant portions of the potential welfare gain.
Photoredox-Catalyzed Intramolecular Aminodifluoromethylation of Unactivated Alkenes

A photoredox catalyzed aminodifluoromethylation of unactivated alkenes has been developed in which HCF2SO2Cl is used as the HCF2 radical source. Sulfonamides were active nucleophiles in the final step of a tandem addition/oxidation/cyclization process to form pyrrolidines, and esters were found to cyclize to form lactones. Thus, a variety of pyrrolidines and lactones were obtained in moderate to excellent yield. In order for the cyclization reactions to be efficient, a combination of a copper catalyst (Cu(dap)2Cl) and silver carbonate was crucial to suppressing a competing chloro, difluoroalkylation process.
An approximate solution method for large risk-averse Markov decision processes

Stochastic domains often involve risk-averse decision makers. While recent work has focused on how to model risk in Markov decision processes using risk measures, it has not addressed the problem of solving large risk-averse formulations. In this paper, we propose and analyze a new method for solving large risk-averse MDPs with hybrid continuous-discrete state spaces and continuous action spaces. The proposed method iteratively improves a bound on the value function using a linearity structure of the MDP. We demonstrate the utility and properties of the method on a portfolio optimization problem.
A Riemann solver for a system of hyperbolic conservation laws at a general road junction

Abstract The kinematic wave model of traffic flow on a road network is a system of hyperbolic conservation laws, for which the Riemann solver is of physical, analytical, and numerical importance. In this paper, we present a new Riemann solver at a general network junction in the demand-supply space. In the Riemann solutions, traffic states on a link include the initial, stationary, and interior states, and a discrete Cell Transmission Model flux function in interior states is used as an entropy condition, which is consistent with fair merging and first-in-first-out diverging rules. After deriving the feasibility conditions for both stationary and interior states, we obtain a set of algebraic equations, and prove that the Riemann solver is well-defined, in the sense that the stationary states, the out-fluxes of upstream links, the in-fluxes of downstream links, and kinematic waves on all links can be uniquely solved. In addition, we show that the resulting global flux function in initial states is the same as the local one in interior states. Hence we presents a new definition of invariant junction models, in which the global and local flux functions are the same. We also present a simplified framework for solving the Riemann problem with invariant junction flux functions.
From Widgets to Digits: Employment Regulation for the Changing Workplace

Introduction Part I. Labor Relations Regimes of the Past: 1. Artisanal production in the nineteenth century 2. The labor system of the industrial era 3. From scientific management to internal labor markets Part II. The Digital Workplace: 4. The changing nature of employment 5. The new employment relationship Part III. Implications of Digital Job Structures for Labor and Employment Law: 6. Implications of the new workplace for labor and employment regulation 7.Disputes over ownership of human capital 8. The changing nature of employment discrimination 9. Unionism in the boundaryless workplace 10. Re-imagining employee representation Part IV. Social Justice in the Digital Era: 11. The crisis in benefits and the collapse of the private welfare state 12. The working rich and the working poor: income inequality in the digital era Conclusion Notes Appendices.
On Bombieri’s asymptotic sieve

If a sequence (an) of non-negative real numbers has best possible distribution in arithmetic progressions, Bombieri showed that one can deduce an asymptotic formula for the sum Σ n≤x a n Λ k (n) for k > 2. By constructing appropriate sequences, we show that any weakening of the well-distribution property is not sufficient to deduce the same conclusion.
Fermentation Kinetics and Model Processes

Publisher Summary This chapter discusses fermentation kinetics particularly as they relate to batch processes, and continuous fermentation. Studies of batch fermentation processes in nearly all development programs involve periodic observations of growth, carbohydrate utilization, and product formation throughout the course of the fermentation. Kinetic analysis is the interpretation of these observations and the factors which influence them, in order to throw light on proposed reaction schemes or fermentation patterns. The crux of any kinetic analysis lies in determining how the rate of product formation and its stoichiometric coefficient vary with respect to the chemical and physical factors influencing them. A refined classification is presented for categorizing fermentation processes. The basis for this classification is a series of typed over-all reactions. Using these reactions and the background available in chemical kinetics, several model processes are suggested for studying such formulations. It is found that a sound and thorough study that combines the fermentation engineer's knowledge of reaction kinetics and their interpretation, the fermentation biochemist's knowledge of the chemistry of the various reactions which occur, and the microbiologist's knowledge in growing and maintaining the active cell tissue which provides the catalytic material for the reactions involved, can easily lead to one of the most substantial technological advances the fermentation industry has ever made.
Spillovers from Climate Policy to Other Pollutants

Climate policy spillovers can be either positive or negative since firms change their production processes in response to climate policies, which may either increase or decrease emissions of other pollutants. Understanding these ancillary benefits or costs has important implications for climate policy design, modeling, and benefit-cost analysis. This paper shows how spillovers can be decomposed into output effects (which have ancillary benefits) and substitution effects (which may have ancillary benefits or ancillary costs). The ambiguous net effect highlights the importance of polluters’ responses to climate policy. I then test for climate policy spillovers in electricity power generation. The estimates are consistent with ancillary benefits from climate policy arising primarily from reductions in output (primarily at older plants) rather than from changes in emissions rates.
Effect of local phase-mismatch on frequency doubling of high-power femtosecond laser pulses under quasi-phase-matched conditions

Summary form only given. Quasi-phase matching (QPM) has been extensively researched for nonlinear interactions. We find from numerical calculations that the local phase-mismatch can significantly affect the second harmonic generation (SHG), especially in situations involving high-power femtosecond pulses where the number of domain periods is limited by group-velocity mismatch (GVM).
Sample complexity of multi-task reinforcement learning

Transferring knowledge across a sequence of reinforcement-learning tasks is challenging, and has a number of important applications. Though there is encouraging empirical evidence that transfer can improve performance in subsequent reinforcement-learning tasks, there has been very little theoretical analysis. In this paper, we introduce a new multi-task algorithm for a sequence of reinforcement-learning tasks when each task is sampled independently from (an unknown) distribution over a finite set of Markov decision processes whose parameters are initially unknown. For this setting, we prove under certain assumptions that the per-task sample complexity of exploration is reduced significantly due to transfer compared to standard single-task algorithms. Our multi-task algorithm also has the desired characteristic that it is guaranteed not to exhibit negative transfer: in the worst case its per-task sample complexity is comparable to the corresponding single-task algorithm.
Inflating the Cube Without Stretching

Here by isometric we mean that the geodesic distance between pairs of points on the non-convex polyhedron is always equal to the geodesic distance between of the corresponding pairs of points on a cube. Alternatively, it means that two surfaces can be triangulated in such a way that they now consist of congruent triangles which are glued according to the same combinatorial rules. For example, if we push a vertex v of a cube C inside as shown in the Figure below, we obtain a polyhedron P whose surface ∂P is isometric to S = ∂C. Of course, vol(P ) < vol(C) in this case.
ARMA time-series modeling with graphical models

We express the classic ARMA time-series model as a directed graphical model. In doing so, we find that the deterministic relationships in the model make it effectively impossible to use the EM algorithm for learning model parameters. To remedy this problem, we replace the deterministic relationships with Gaussian distributions having a small variance, yielding the stochastic ARMA (σARMA) model. This modification allows us to use the EM algorithm to learn parameters and to forecast, even in situations where some data is missing. This modification, in conjunction with the graphical-model approach, also allows us to include cross predictors in situations where there are multiple time series and/or additional non-temporal covariates. More surprising, experiments suggest that the move to stochastic ARMA yields improved accuracy through better smoothing. We demonstrate improvements afforded by cross prediction and better smoothing on real data.
Representing and reasoning with probabilistic knowledge: a Bayesian approach

PAGODA (Probabilistic Autonomous GOal-Directed Agent) is a model for autonomous learning in probabilistic domains [desJardins, 1992] that incorporates innovative techniques for using the agent's existing knowledge to guide and constrain the learning process and for representing, reasoning with, and learning probabilistic knowledge. This paper describes the probabilistic representation and inference mechanism used in PAGODA. PAGODA forms theories about the effects of its actions and the world state on the environment over time. These theories are represented as conditional probability distributions. A restriction is imposed on the structure of the theories that allows the inference mechanism to find a unique predicted distribution for any action and world state description. These restricted theories are called uniquely predictive theories. The inference mechanism, Probability Combination using Independence (PCI), uses minimal independence assumptions to combine the probabilities in a theory to make probabilistic predictions.
Access to Financial Services in Brazil

This study evaluated present levels of access to financial services in Brazil and government policies that have had an impact on access. Based on these findings, the study explored options for increasing future access to financial services in Brazil. The first section of this summary highlights the core conclusions to emerge from the study and their implications for government policy. The next section describes the findings and recommendations of each chapter, and is followed by an in-depth look at specific areas examined by the study.
The Option to Try Again: Valuing a Sequence of Dependent Trials

We examine the value of a petroleum exploration prospect that is to be exploited via a series of possibly dependent trials. The pattern and strength of dependence among trials is linked to a real option that affects the expected economic value of the prospect. We develop an exact, yet intuitive, expression for the expected value of such a prospect. We also show that two intuitive approaches to valuation provide strict upper and lower bounds for the actual value. Finally, the impact of dependence is shown to be monotonic: each increase in the degree of dependence among trials results in a further reduction in expected value of the prospect.
Type ia supernovae as extragalactic distance indicators

Because Type Ia supernovae (SNe Ia) are not perfect standard candles, it is important to be able to use distance–independent observables (DIOs) to define subsets of SNe Ia that are “nearly standard candles” or to correct SN Ia absolute magnitudes to make them nearly homogeneous (“standardized candles”). This is not cruci al for the measurement of H o but it is for the measurement of q o and of parent–galaxy peculi ar velocities. We discuss the use of various photometric and spectroscopic SN Ia DIOs, and a parent–galaxy DIO, for this purpose. We also discuss the status of the absolute–magnitude calibration of SNe Ia. We find that SNe Ia, whether calibrated by means of (1) Cepheids in their parent g al axies, (2) fitting their optical –ultraviolet spectra with detailed non-LTE model atmosphere calculations, or (3) by considering that the light curve is powered by the decay of radioactive 56Ni, firmly indicate that the value of H o is low, less than or about 60 km s-1 Mpc-1. Some issues regarding the determination of q o by means of SNe Ia are discussed briefly. Finally, we conjecture that even if q o=0.5, there probably is no cosmic age problem.
Application of Coarse Integration to Bacterial Chemotaxis

We have developed and implemented a numerical evolution scheme for a class of stochastic problems in which the temporal evolution occurs on widely separated time scales and for which the slow evolution can be described in terms of a small number of moments of an underlying probability distribution. We demonstrate this method via a numerical simulation of chemotaxis in a population of motile, independent bacteria swimming in a prescribed gradient of a chemoattractant. The microscopic stochastic model, which is simulated using a Monte Carlo method, uses a simplified deterministic model for excitation/adaptation in signal transduction, coupled with a realistic, stochastic description of the flagellar motor. We show that projective time integration of "coarse" variables can be carried out on time scales long compared to those of microscopic dynamics. Our coarse description is based on the spatial cell density distribution. Thus we are assuming that the system "closes" on this variable so that it can be descri...
Incentives for Partitioning High-Level Waste

The safety incentives for separating and eliminating various elements from high-level radioactive waste prior to final geologic isolation have been examined. The study required evaluation of numero...
Improved pseudorandom generators for depth 2 circuits

We prove the existence of a poly(n,m)-time computable pseudorandom generator which "1/poly(n,m)-fools" DNFs with n variables and m terms, and has seed length O(log2nm ċ log log nm). Previously, the best pseudorandom generator for depth-2 circuits had seed length O(log3 nm), and was due to Bazzi (FOCS 2007). It follows from our proof that a 1/mO(log mn)-biased distribution 1/poly(nm)-fools DNFs with m terms and n variables. For inverse polynomial distinguishing probability this is nearly tight because we show that for every m, δ there is a 1/mΩ(log 1/δ)-biased distribution X and a DNF φ with m terms such that φ is not δ-fooled by X. For the case of read-once DNFs, we show that seed length O(log mn ċ log 1/δ) suffices, which is an improvement for large δ. It also follows from our proof that a 1/mO(log 1/δ)-biased distribution δ-fools all read-once DNF with m terms. We show that this result too is nearly tight, by constructing a 1/mΩ(log 1/δ)-biased distribution that does not δ-fool a certain m-term read-once DNF.
Admitting Students to Selective Education Programs: Merit, Profiling, and Affirmative Action

Minority and disadvantaged students are typically underrepresented in selective programs that use merit-based admission. Urban school districts may set different referral and admission thresholds based on income and race (affirmative action), and they may exploit differences in achievement relative to ability across race and income groups (profiling). We develop and estimate a model that provides a unified treatment of affirmative action and profiling. We find profiling by race and income and affirmative action for low-income students. Counterfactual analysis reveals that these policies achieve more than 80 percent of African American enrollment that could be attained by race-based affirmative action.
Surface sensitive microfluidic optomechanical ring resonator sensors

Sensitivity of the optomechanical resonator to the surface mass change is demonstrated to be 1.2 Hz per pg/mm2 by gradually removing SiO 2 molecules from the resonator surface. A detection limit of 83 pg/mm2 is achieved.
A game theoretical approach to modeling full-duplex information dissemination

One major function of social networks (e.g., massive online social networks) is the dissemination of information such as scientific knowledge, news, and rumors. Information can be propagated by the users of the network via natural connections in written, oral or electronic form. The information passing from a sender to a receiver intrinsically involves both of them considering their self-perceived knowledge, reputation, and popularity, which further determine their decisions of whether or not to forward the information and whether or not to provide feedback. To understand such human aspects of the information dissemination, we propose a game theoretical model of the two-way full duplex information for-warding and feedback mechanisms in a social network that take into account the personalities of the communicating actors (including their perceived knowledgeability, reputation, and desire for popularity) and the global characteristics of the network. The model demonstrates how the emergence of social networks can be explained in terms of maximizing game theoretical utility.
Actively learning to verify safety for FIFO automata

We apply machine learning techniques to verify safety properties of finite state machines which communicate over unbounded FIFO channels. Instead of attempting to iteratively compute the reachable states, we use Angluin’s L* algorithm to learn these states symbolically as a regular language. The learnt set of reachable states is then used either to prove that the system is safe, or to produce a valid execution of the system that leads to an unsafe state (i.e. to produce a counterexample). Specifically, we assume that we are given a model of the system and we provide a novel procedure which answers both membership and equivalence queries for a representation of the reachable states. We define a new encoding scheme for representing reachable states and their witness execution; this enables the learning algorithm to analyze a larger class of FIFO systems automatically than a naive encoding would allow. We show the upper bounds on the running time and space for our method. We have implemented our approach in Java, and we demonstrate its application to a few case studies.
Perspectives on Fetal Surgery

In 1982, we wrote: “Experimentation with fetal surgery has come of age, and its routine clinical application seems inevitable.”1 We still believe this statement, but the road from experimentation to therapy will be longer than most observers had originally predicted. The results to date have been disappointing, and although research continues, there is no longer a general expectation of immediate therapeutic application of these new surgical techniques. Nonetheless, the stakes remain high and the implications of successful fetal surgery for medicine, society, the pregnant woman, and the fetus are profound. In this chapter we review the current medical indications for fetal surgery, as well as the major ethical and legal issues that the use of this technology raises now and in the future.
A framework for inference-directed data mining

This paper presents a second-path inference-detection approach based on association cardinalities.*It is applicable to the detection of second paths that do not involve functional dependencies or foreign keys. It provides for an analysis sieve that begins with the analysis of an object model of the database. The goal of the analysis is to detect cases in the database in which a small number of values in the target entity can be associated with a single value in the anchor entity. The number of values is called the association cardinality from anchor to target. Inference vulnerabilities occur for cases of small association cardinalities. The analysis sieve processes the data model of the database to detect cases of small association cardinality. For cases with high cardinality associations, the sieve mines the database to detect cases of small instance-level association cardinalities.
Theory of Remote Image Formation

This book was first published in 2004. In many applications, images, such as ultrasonic or X-ray signals, are recorded and then analyzed with digital or optical processors in order to extract information. Such processing requires the development of algorithms of great precision and sophistication. This book presents a unified treatment of the mathematical methods that underpin the various algorithms used in remote image formation. The author begins with a review of transform and filter theory. He then discusses two- and three-dimensional Fourier transform theory, the ambiguity function, image construction and reconstruction, tomography, baseband surveillance systems, and passive systems (where the signal source might be an earthquake or a galaxy). Information-theoretic methods in image formation are also covered, as are phase errors and phase noise. Throughout the book, practical applications illustrate theoretical concepts, and there are many homework problems. The book is aimed at graduate students of electrical engineering and computer science, and practitioners in industry.
What price the court of St. James? Political influences on ambassadorial postings of the United States of America

This paper explores the appointment of career diplomats and political appointees to ambassadorial positions. We present models of the strategic interaction of political donors and presidential candidates, which predicts that donations will match the quality of diplomatic posting granted by the candidate. We test this prediction and confirm it for four presidential terms representing two presidents and 764 diplomatic postings over the 2000 to 2013 period. This allows for the generation of a price list associated with a range of desirable diplomatic posts. This paper provides evidence in support of the proposition that ambassadorships, in locations that are deemed desirable such as Western Europe, are awarded as a form of patronage in return for campaign contributions.
Income diversification in Zimbabwe : welfare implications from urban and rural areas

The author examines, taking into account the urban-rural divides, the changes and welfare implications of income diversification in Zimbabwe following macroeconomic policy changes and droughts of the early 1990s. Data from two comparable national income, consumption and expenditure surveys in 1990-91 and 1995-96, which straddled a period of economic volatility and natural disasters, show that the percentage of households earning income from private and informal sources grew considerably, while that from government and formal sources declined in the aftermath of the drought and policy changes. The author finds that, in general, rural households tend to have a more diversified portfolio of income compared with their urban counterparts, and the degree of diversification decreases with the level of urbanization. However, there are important differences in the level of diversification within the rural and urban areas depending on wealth: While the relatively better-off households have a more diversified income base in rural areas, it is the poor who pursue multiple income sources in urban areas. A decomposition of changes in welfare indicates that the total contribution of income diversification is large and increased between 1990-91 and 1995-96 in both urban and rural areas. On the other hand, there were significant declines in returns to human and physical capital assets during the same period. The findings suggest that households with a more diversified income base are better able to withstand the unfavorable impacts of the policy and weather shocks. The fact that relatively better-off households have a more diversified income base following the shocks implies that the poor are more vulnerable to economic changes unaccompanied by well-designed safety nets.
Insider Lending: Banks, Personal Connections, and Economic Development in Industrial New England

Acknowledgements Introduction 1. Vehicles for accumulating capital 2. Insider lending and Jacksonian hostility towards banks 3. Engines of economic development 4. The decline of insider lending and the problem of determining creditworthiness 5. Professionalization and specialization 6. The merger movement in banking Conclusion.