cssi/SciSciGPT-SciSciNet huggingface dataset:
Learning Automata from Ordered Examples

Connectionist learning models have had considerable empirical success, but it is hard to characterize exactly what they learn. The learning of finite-state languages (FSL) from example strings is a domain which has been extensively studied and might provide an opportunity to help understand connectionist learning. A major problem is that traditional FSL learning assumes the storage of all examples and thus violates connectionist principles. This paper presents a provably correct algorithm for inferring any minimum-state deterministic finite-state automata (FSA) from a complete ordered sample using limited total storage and without storing example strings. The algorithm is an iterative strategy that uses at each stage a current encoding of the data considered so far, and one single sample string. One of the crucial advantages of our algorithm is that the total amount of space used in the course of learning for encoding any finite prefix of the sample is polynomial in the size of the inferred minimum state deterministic FSA. The algorithm is also relatively efficient in time and has been implemented. More importantly, there is a connectionist version of the algorithm that preserves these properties. The connectionist version requires much more structure than the usual models and has been implemented using the Rochester Connectionist Simulator. We also show that no machine with finite working storage can iteratively identify the FSL from arbitrary presentations.
Low rank perturbations of large elliptic random matrices

We study the asymptotic behavior of outliers in the spectrum of bounded rank perturbations of large random matrices. In particular, we consider perturbations of elliptic random matrices which generalize both Wigner random matrices and non-Hermitian random matrices with iid entries. As a consequence, we recover the results of Capitaine, Donati-Martin, and Feral for perturbed Wigner matrices as well as the results of Tao for perturbed random matrices with iid entries. Along the way, we prove a number of interesting results concerning elliptic random matrices whose entries have finite fourth moment; these results include a bound on the least singular value and the asymptotic behavior of the spectral radius.
The evolution and structure of pulsar wind nebulae

AbstractPulsars steadily dissipate their rotational energy via relativistic winds. Confinement of these outflows generates luminous pulsar wind nebulae, seen across the electromagnetic spectrum in ...
ADMiRA: Atomic Decomposition for Minimum Rank Approximation

In this paper, we address compressed sensing of a low-rank matrix posing the inverse problem as an approximation problem with a specified target rank of the solution. A simple search over the target rank then provides the minimum rank solution satisfying a prescribed data approximation bound. We propose an atomic decomposition providing an analogy between parsimonious representations of a sparse vector and a low-rank matrix and extending efficient greedy algorithms from the vector to the matrix case. In particular, we propose an efficient and guaranteed algorithm named atomic decomposition for minimum rank approximation (ADMiRA) that extends Needell and Tropp's compressive sampling matching pursuit (CoSaMP) algorithm from the sparse vector to the low-rank matrix case. The performance guarantee is given in terms of the rank-restricted isometry property (R-RIP) and bounds both the number of iterations and the error in the approximate solution for the general case of noisy measurements and approximately low-rank solution. With a sparse measurement operator as in the matrix completion problem, the computation in ADMiRA is linear in the number of measurements. Numerical experiments for the matrix completion problem show that, although the R-RIP is not satisfied in this case, ADMiRA is a competitive algorithm for matrix completion.
The role of FDG-PET in defining prognosis of Hodgkin lymphoma for early-stage disease.

Given the excellent survival rates for early-stage Hodgkin lymphoma (HL), the young age of many patients, and concerns regarding acute and late treatment-related toxicities, there is a desire to have a predictive tool that enables therapy to be tailored toward the individual patient. Early (or interim) 18F-fluorodeoxyglucose positron emission tomography with computerized tomography (FDG-PET/CT), as a test of tumor sensitivity to ongoing/planned therapy, has been shown to be prognostic for survival in HL. Based on results of interim FDG-PET/CT, therapy may be subsequently modified through minimization or via intensification for low- and high-risk patient populations, respectively (ie, response-adapted therapy). Important data have been generated to standardize the interpretability and reproducibility of interim FDG-PET/CT (eg, the Deauville 5-point system), and observational and noncontrolled prospective studies have produced evidence supporting the hypothesis that response-adapted therapy may potentially serve as a predictive tool. Furthermore, results from noninferiority phase 3 clinical trials randomizing early-stage HL patients with negative interim FDG-PET/CT to combined modality therapy versus chemotherapy alone have been reported. The current collective findings from these randomized early-stage HL studies have shown that acute relapse rates are lower with combined modality therapy, even in patients with negative interim FDG-PET/CT. Additional randomized response-adapted studies are ongoing and novel FDG-PET/CT applications involving quantitative techniques and innovative imaging modalities are being investigated to identify more robust imaging biomarkers. Treatment of early-stage HL remains a clinical management choice for physicians and patients to make with consideration of acute and long-term outcomes.
Modeling Interest Rate Parity: A System Dynamics Approach

The theory of uncovered interest rate parity has enjoyed very little empirical support. Despite the fact that global financial markets trade seven days a week, twenty-four hours a day, and communication takes place almost instantaneously, there are strong indications that differences in expected rates of return across countries can be non-zero and large for extended periods of time. However, these deviations display a pattern within which there is an important clue regarding their cause. Changes in the differences between expected rates of return across countries largely correspond to changes in the differences between national interest rates. In other words, when agents expect the rate of return (taking into account both interest rates and forecast exchange rate movements) to be higher in one country than another, that country also tends to have the higher interest rates. This means, as will be demonstrated below, that deviations from uncovered interest rate parity cannot be explained (as has been argued elsewhere) by relying on the assumption that agents perceive some assets to be riskier than others. A model of international financial flows that incorporates John Maynard Keynes' concept of forecast confidence, however, has no difficulty explaining this commonly observed phenomenon. The purpose of this paper is to show the superiority of Keynes' approach by comparing three system dynamics models of the relationship among interest and exchange rates: one based on traditional uncovered interest rate parity, one with risk, and one with forecast confidence. It will be demonstrated that only the last produces patterns consistent with those observed in the real world. This paper is an extension of the empirical study undertaken in Harvey 2004.
Swan conductors for p-adic differential modules, I: A local construction

We define a numerical invariant, the differential Swan conductor, for certain differential modules on a rigid analytic annulus over a p-adic field. This gives a definition of a conductor for p-adic Galois representations with finite local monodromy over an equal characteristic discretely valued field, which agrees with the usual Swan conductor when the residue field is perfect. We also establish analogues of some key properties of the usual Swan conductor, such as integrality (the Hasse–Arf theorem), and the fact that the graded pieces of the associated ramification filtration on Galois groups are abelian and killed by p.
Syntheses of Ring C Oxysterols: Inhibitors of Sterol Biosynthesis

Oxygenated derivates of cholesterol and lanosterol, known as oxysterols, have consistently displayed significant activity as inhibitors of 3-hydroxy-3-methylglutaryl (HMG) CoA reductase, a key regulatory enzyme in sterol biosynthesis. We have developed the chemical syntheses of ring C oxysterols for evaluation as inhibitors of sterol biosynthesis. A key intermediate in the chemical synthesis was 3β-benzoyloxy-9α, 1α-epoxy-5α-cholest-7-ene (1), whose structure was confirmed by X-ray crystallographic analysis and is presented herein.
MONEY HOLDINGS, INFLATION, AND WELFARE IN A COMPETITIVE MARKET*

This paper examines an environment where money is essential and agents exchange in perfectly-competitive, Walrasian markets. Agents consume and produce a homogeneous good, but hold money to purchase consumption in the event of a relatively low productivity shock. A Walrasian market delivers a non-degenerate distribution of money holdings across agents and avoids some of the computational difficulties associated with the market and pricing assumptions of bilateral matching and bargaining common to search-theoretic environments. The model is calibrated to long-run US velocity, and the welfare costs of inflation are assessed for variable buyer-seller ratios and persistent states of buying and selling.
Impact of boundary conditions on entrainment and transport in gravity currents

Gravity currents have been studied numerically and experimentally both in the laboratory and in the ocean. The question of appropriate boundary conditions is still challenging for most complex flows. Gravity currents make no exception— appropriate, physically and mathematically sound boundary conditions are yet to be found. This task is further complicated by the technical limitations imposed by the current oceanographic techniques. In this paper, we make a first step toward a better understanding of the impact of boundary conditions on gravity currents. Specifically, we use direct numerical simulations to investigate the effect that the popular Neumann, and less popular Dirichlet boundary conditions on the bottom continental shelf have on the entrainment and transport of gravity currents. The finding is that gravity currents under these two different boundary conditions differ most in the way they transport heat from the top towards the bottom. This major difference occurs at medium temperature ranges. Entrainment and transport at high temperatures also show significant differences. Published by Elsevier Inc.
Power Analysis of Artificial Selection Experiments Using Efficient Whole Genome Simulation of Quantitative Traits

Evolve and resequence studies combine artificial selection experiments with massively parallel sequencing technology to study the genetic basis for complex traits. In these experiments, individuals are selected for extreme values of a trait, causing alleles at quantitative trait loci (QTL) to increase or decrease in frequency in the experimental population. We present a new analysis of the power of artificial selection experiments to detect and localize quantitative trait loci. This analysis uses a simulation framework that explicitly models whole genomes of individuals, quantitative traits, and selection based on individual trait values. We find that explicitly modeling QTL provides qualitatively different insights than considering independent loci with constant selection coefficients. Specifically, we observe how interference between QTL under selection affects the trajectories and lengthens the fixation times of selected alleles. We also show that a substantial portion of the genetic variance of the trait (50–100%) can be explained by detected QTL in as little as 20 generations of selection, depending on the trait architecture and experimental design. Furthermore, we show that power depends crucially on the opportunity for recombination during the experiment. Finally, we show that an increase in power is obtained by leveraging founder haplotype information to obtain allele frequency estimates.
Is Retheta/Me a Meaningful Transition Criterion?

usually Reθ/Me = const. Also since Reθ varies as the square root of a length Reynolds number, any scatter in Reθ is greatly amplified when inverted to get a length transition Reynolds number or a length to transition. There is no apparent physics basis for this form of transition correlation. In this paper, the roles of modal (T-S, crossflow, Gortler, etc) and non-modal (transient growth) mechanisms on the transition process will be described. For modal disturbances, the physics based transition estimations are done by e methods. On the other hand, transient growth methods have been successfully applied in cases where the transition is due to surface roughness. These methods take into account many of the factors that can affect transition such as pressure gradient, surface temperature level, suction or blowing, surface roughness, etc. They also can suggest design changes that can lead to transition delay. Successful
Capital Controls: a Political Economy Approach

The paper examines the economic consequences of political conflicts that arise when countries implement capital controls. In an overlapping-generations model, agents vote on whether to open or close an economy to capital flows. The young (workers) receive income only from wages while the old (capitalists) receive income only from savings. The authors characterize the set of stationary equilibria for an infinite-horizon game. Assuming dynamic efficiency, when the median representative is a worker (capitalist), capitalimporting countries will open (close) while capital-exporting countries will close (open). These predicted patterns are consistent with data on liberalization policies over time and across various countries.
Theory and experiment: What are the questions? ☆

This paper deals generally with testing questions that arise both when experimental observations are in accord with the actions we predict, and when they are not. In both cases the inference of truth from observation is inherently ambiguous, and we face the daunting challenge of using our experimental skills and imagination to reduce this ambiguity. Primarily and most difficult of all we have to constantly reevaluate everything, including ourselves, especially in examining how we talk about and interpret our data. Although I will be drawing on examples and experience from laboratory experiments, the issues I consider apply just as meaningfully to other empirical studies whether from field experiments or observations from past records of socioeconomic processes.
Incentives to Inflate Reported Cash from Operations Using Classification and Timing

ABSTRACT: This study examines when firms inflate reported cash from operations in the statement of cash flows (CFO) and the mechanisms through which firms manage CFO. CFO management is distinct from earnings management. Unlike the manipulation of accruals, firms cannot manage CFO with biased estimates, but must resort to classification and timing. I identify four firm characteristics associated with incentives to inflate reported CFO: (1) financial distress, (2) a long-term credit rating near the investment/non-investment grade cutoff, (3) the existence of analyst cash flow forecasts, and (4) higher associations between stock returns and CFO. Results indicate that, even after controlling for the level of earnings, firms upward manage reported CFO when the incentives to do so are particularly high. Specifically, firms manage CFO by shifting items between th estatement of cash flows categories both within and outside the boundaries of generally accepted accounting principles (GAAP), and by timing certain tr...
What’s in a Picture? Evidence of Discrimination from Prosper.com

Abstract:We find evidence of significant racial disparities in a new type of credit market known as peer-to-peer lending. Loan listings with blacks in the attached picture are 25 to 35 percent less likely to receive funding than those of whites with similar credit profiles. Despite the higher average interest rates charged to blacks, lenders making such loans earn a lower net return compared to loans made to whites with similar credit profiles because blacks have higher relative default rates. These results provide insight into whether the discrimination we find is taste-based or statistical.
Scheduler vulnerabilities and coordinated attacks in cloud computing

In hardware virtualization a hypervisor provides multiple Virtual Machines VMs on a single physical system, each executing a separate operating system instance. The hypervisor schedules execution of these VMs much as the scheduler in an operating system does, balancing factors such as fairness and I/O performance. As in an operating system, the scheduler may be vulnerable to malicious behavior on the part of users seeking to deny service to others or maximize their own resource usage.Recently, publically available cloud computing services such as Amazon EC2 have used virtualization to provide customers with virtual machines running on the provider's hardware, typically charging by wall clock time rather than resources consumed. Under this business model, manipulation of the scheduler may allow theft of service at the expense of other customers, rather than merely re-allocating resources within the same administrative domain.We describe a flaw in the Xen scheduler allowing virtual machines to consume almost all CPU time, in preference to other users, and demonstrate kernel-based and user-space versions of the attack. We show results demonstrating the vulnerability in the lab, consuming as much as 98% of CPU time regardless of fair share, as well as on Amazon EC2, where Xen modifications protect other users but still allow theft of service following the responsible disclosure model, we have reported this vulnerability to Amazon; they have since implemented a fix that we have tested and verified. We provide a novel analysis of the necessary conditions for such attacks, and describe scheduler modifications to eliminate the vulnerability. We present experimental results demonstrating the effectiveness of these defenses while imposing negligible overhead.Also, cloud providers such as Amazon's EC2 do not explicitly reveal the mapping of virtual machines to physical hosts [in: ACM CCS, 2009]. Our attack itself provides a mechanism for detecting the co-placement of VMs, which in conjunction with appropriate algorithms can be utilized to reveal this mapping. Other cloud computing attacks may use this mapping algorithm to detect the placement of victims.
Virtual Algebraic Lie Theory: Tilting Modules and Ringel Duals for Blob Algebras

In this paper we construct a representation of the blob algebra [22] over a ring allowing base change to every interesting (i.e. non–semisimple) specialisation which, in quasihereditary specialisations, passes to a full tilting module. The Temperley–Lieb algebras are a tower T0(q) ⊂ T1(q) ⊂ .. of one–parameter finite dimensional algebras [28], each with a basis independent of q. These algebras are quasihereditary [3, 8] except in case q+q = 0. Accordingly one may in principle construct tilting modules, full tilting modules, and corresponding Ringel duals. In fact, if V is a free module of rank 2 over the ground ring then Tn(q) has an action on V , and it is straightforward to show (see later) that V ⊗n is a full tilting module in the quasihereditary cases. Since V ⊗n exists over the ground ring, the Ringel dual can be constructed without having to pick a specialisation. The cases of n finite of this dual are a nested sequence of quotients of the quantum group Uqsl2 [17, 11]. This q–deformable duality and glorious limit structure [16] (more usually observed with Uqsl2 as the starting point) provides the mechanism for massive exchange of representation theoretic information between the two sides [26, 10, 13, 4, 18]. In particular the weight theory of Uqsl2 controls the representation theory of Tn(q) for all n simultaneously (as localisations of a global limit). The blob algebras are a tower b0 ⊂ b1 ⊂ .. of two–parameter finite dimensional algebras (and bn ⊃ Tn(q)). They are quasihereditary except at a finite set of parameter values. Accordingly one may in principle construct tilting modules and so on. Ab initio one would have to expect such a construction to depend on the specialisation, as indecomposable tilting modules do [24]. On the other hand, it turns out [23] that bn has an action on V , and in this paper we show that V ⊗2n is a full tilting module in the quasihereditary cases. Historically, Tn(q) and Uqsl2 were studied extensively separately, before the full tilting module/Ringel duality connection was known, but if one side, and the appropriate full tilting module, had been discovered first, the passage to the Ringel dual would rightly have been regarded as quite a significant spin–off! The bn tilting property of V ⊗2n is a striking result, in as much as it places us in a position analogous to this (as it were, before the discovery of quantum groups).
Using the X-Ray Dust Scattering Halo of 4U 1624–490 to Determine Distance and Dust Distributions

We present X-ray dust scattering halo results based on our 76 ks Chandra ACIS-S/HETGS observation of the LMXB dipping source 4U 1624-490. Through analysis of the halo light curves with 2-6 keV spectra over the persistent and dipping periods, we estimate a geometric distance of ~15 kpc to 4U 1624-490. We also fit halo radial profiles with different ISM dust grain models to assess the location, uniformity, and density of the halo. Our analysis shows that the dust spatial distribution is not uniform along the line of sight; rather, it is consistent with the spiral arm structure mapped in H II. The large difference between the absorption hydrogen column (N ~ 8 × 1022 cm-2; probes all gas along the line of sight) derived from broadband spectral fitting and the scattering hydrogen column (N ~ 4 × 1022 cm-2; probes only Galactic gas) derived from our studies of the 4U 1624-490 X-ray halo suggests that a large fraction of the column is local to the X-ray binary. We also present (and apply) a new method for assessing the Chandra point-spread function at large (>50'') angles, through use of the time delays from the observed dips.
Constructions of codes from number fields

We define number-theoretic error-correcting codes based on algebraic number fields, thereby providing a generalization of Chinese remainder codes akin to the generalization of Reed-Solomon codes to algebraic-geometric codes. Our construction is very similar to (and in fact less general than) the one given by Lenstra (1986), but the parallel with the function field case is more apparent, since we only use the non-Archimedean places for the encoding. We prove that over an alphabet size as small as 19 there even exist asymptotically good number field codes of the type we consider. This result is based on the existence of certain number fields that have an infinite class field tower in which some primes of small norm split completely.
Multigraded combinatorial Hopf algebras and refinements of odd and even subalgebras

We develop a theory of multigraded (i.e., ? l -graded) combinatorial Hopf algebras modeled on the theory of graded combinatorial Hopf algebras developed by Aguiar et al. (Compos. Math. 142:1---30, 2006). In particular we introduce the notion of canonical k-odd and k-even subalgebras associated with any multigraded combinatorial Hopf algebra, extending simultaneously the work of Aguiar et al. and Ehrenborg. Among our results are specific categorical results for higher level quasisymmetric functions, several basis change formulas, and a generalization of the descents-to-peaks map.
Standardization for the biomedical photographic department.

Biomedical photographers work in a variety of scientific and aesthetic disciplines. Photographs with the greatest scientific value are those that are made under repeatable photographic conditions and that meet the aesthetic criteria of the viewer. The photographic parameters include sharpness, detail, colour balance and films and format. The aesthetic criteria include composition, clarity, and information content. These parameters and visual criteria may be met without great difficulty in a one-man department, but they pose more of a problem in a department of several personnel because of individual priorities and abilities. By standardizing photographic procedures, however, a high percentage of scientifically useful and visually acceptable photographs can be attained from several personnel on changing assignments.This article presents a method for developing standard procedures along with illustrations of typical subjects. In addition, a review system is described that facilitates the updating of informa...
Load aware traffic engineering for mesh networks

Wireless Mesh Network (WMN) is a multi-hop mesh network that consists of mesh routers and mesh clients, where mesh routers are static and form the backbone of the mesh network. The static nature of mesh nodes imposes requirements for designing routing metrics that support high-throughput and low packet delay. This article considers the problem of Interference-Load Aware routing in multi-channel Wireless Mesh Networks. We propose a new Interference-Load Aware routing metric, ILA, that finds paths with reduced inter-flow and intra-flow interference. The aim of this metric is to route the traffic through congestion free areas and balance the load amongst the network nodes. We incorporate this new metric in the well known AODV routing protocol and study the performance of ILA through simulations. We show that the proposed metric is able to adapt to changes in interfering traffic better than existing link metrics such as ETT, WCETT and MIC. We also demonstrate that our metric delivers high-throughput in multi-channel networks.
Calculation Verification: Pointwise Estimation of Solutions and Their Method-Associated Numerical Error

Calculation verification is a method of quantifying the convergence properties of a specific implementation of an algorithm without using an exact solution, whereas code verification does use an exact solution. Calculating global convergence while performing calculation verification can be problematic as no exact solution is generally available. A second difficulty sometimes encountered in both code and calculation verification is when the computed solutionsatapointinspaceconvergeinanoscillatorymanner,makingcalculationofconvergence difficult.An extension to the standard method of calculation and code verification is explored which may address both of these issues. The proposed method uses pointwise convergence analysis to estimate global convergence behavior by first estimating a discrete solution to the partial differential equations. The estimated solution is then used in place of an exact solution to evaluate global convergence rates when conducting a calculation verification analysis. Additionally, the absolute value of the pointwise error is calculated, allowing for monotonic or oscillatory convergence. This method was tested on four pure hydrodynamics problems usingtheEuleriancodeRAGE.Alinearacousticwaveanda1-DRiemannproblembothhave exact mathematical solutions, which were compared to the estimated solution. For these two problems both code and calculation verification methods were applied.A nonlinear acoustic wave and 2-D Riemann problem both have no exact solutions, but the estimated solution was shown to be useful in providing a more accurate solution on a coarse grid than the calculated solution. For these two problems, only a calculation verification analysis was conducted.
On \kappa -noncollapsed complete noncompact shrinking gradient Ricci solitons which split at infinity

We discuss some geometric conditions under which a complete noncompact shrinking gradient Ricci soliton will split at infinity.
Dynamic Adaptive Anti-Jamming via Controlled Mobility

In this paper, the mobility of network nodes is explored as a new promising approach for jamming defense. To fulfill it, properly designed node motion that can intelligently adapt to the jammer's action is crucial. In our study, anti-jamming mobility control is investigated in the context of the single and multiple commodity flow problems, in the presence of intelligent mobile jammers which can respond to the evasion of legitimate nodes as well. Based on spectral graph theory, two new spectral quantities, single- and multi-weighted Cheeger constants and corresponding eigenvalue variants, are constructed to direct motions of the defender and the attacker in this dynamic adaptive competition. Both analytical and simulation results are presented to justify the effectiveness of the proposed approach. Furthermore, the proposed scheme can also be applied in cognitive radio networks to reconfigure the secondary users in the presence of mobile primary users.
An Embedded Bottom Boundary Layer Formulation for Z-Coordinate Ocean Models

Abstract An embedded bottom boundary layer (EBBL) scheme is developed to improve the bottom topographic representation in z-coordinate ocean general circulation models. The EBBL scheme is based on the combined techniques of an embedded topography-following slab, an explicit turbulent bottom boundary layer (BBL), and a generalized pressure gradient formulation. The coupling between the interior z-level model and the EBBL model is achieved by exchanging entrainment/detrainment and pressure gradients at the bottom layer surface, which allows temporal and spatial variations. The EBBL is implemented into one of the most widely used z-coordinate models, the Modular Ocean Model (MOM). A test problem with a source of dense water on a slope is used. The new EBBL produces significantly more realistic plume spreading than the existing BBL scheme of Killworth and Edwards and is comparable to the results from a topography-following coordinate model (SCRUM), which is believed to be more suitable for such a problem. Cal...
Centre SIM: hour-by-hour travel demand forecasting for mobile source emission estimation

Urban Airshed Models for estimating air pollution concentrations in a region require travel demand models that can produce hour-by-hour mobile source emission estimates. Regional simulation models of this type are currently created and tested in Australia, Europe, Japan, and the United States using a variety of theories, decision-making formalisms, and operational implementation methods. On one hand, these relatively new conceptualizations and models of transport systems have improved in a substantial way the realism of computerized decision support tools and have the potential of improving quantification of environmental impacts and transport management/control strategies. On the other hand, however, these systems require a substantial amount of data and understanding about behavior that very often are not readily available and for this require additional research. In this paper first a brief comparative overview of conceptual designs, data requirements, and models used in computer simulation of regional transport systems is provided. Then, the basic ingredients of a model system called Longitudinal Integrated Forecasting Environment (LIFE) that contains a demographic simulator, a daily time allocation and travel scheduling system, and a Geographic Information System are also presented. One component of this model system emphasizing the spatial and temporal dimensions of travel demand is described in more detail together with its validation using observed traffic data. The paper concludes with a summary and a few directions for model improvements.
Discovering the skyline of web databases

Many web databases are "hidden" behind proprietary search interfaces that enforce the top-k output constraint, i.e., each query returns at most k of all matching tuples, preferentially selected and returned according to a proprietary ranking function. In this paper, we initiate research into the novel problem of skyline discovery over top-k hidden web databases. Since skyline tuples provide critical insights into the database and include the top-ranked tuple for every possible ranking function following the monotonic order of attribute values, skyline discovery from a hidden web database can enable a wide variety of innovative third-party applications over one or multiple web databases. Our research in the paper shows that the critical factor affecting the cost of skyline discovery is the type of search interface controls provided by the website. As such, we develop efficient algorithms for three most popular types, i.e., one-ended range, free range and point predicates, and then combine them to support web databases that feature a mixture of these types. Rigorous theoretical analysis and extensive real-world online and offline experiments demonstrate the effectiveness of our proposed techniques and their superiority over baseline solutions.
Hydrogeologic influence on changes in snowmelt runoff with climate warming: Numerical experiments on a mid-elevation catchment in the Sierra Nevada, USA

Summary The role of hydrogeology in mediating long-term changes in mountain streamflow, resulting from reduced snowfall in a potentially warmer climate, is currently not well understood. We explore this by simulating changes in stream discharge and evapotranspiration from a mid-elevation, 1-km2 catchment in the southern Sierra Nevada of California (USA) in response to reduced snowfall under warmer conditions, for a plausible range in subsurface hydrologic properties. Simulations are performed using a numerical watershed model, the Penn State Integrated Hydrologic Model (PIHM), constrained by observations from a meteorological station, stream gauge, and eddy covariance tower. We predict that the fraction of precipitation occurring as snowfall would decrease from approximately 47% at current conditions to 25%, 12%, and 5% for air temperature changes of +2, +4, and +6 °C. For each of these warming scenarios, changes in mean annual discharge and evapotranspiration simulated by the different plausible soil models show large ranges relative to averages, with coefficients of variation ranging from −3 to 3 depending on warming scenario. With warming and reduced snowfall, substrates with greater storage capacity show less soil moisture limitation on evapotranspiration during the late spring and summer, resulting in greater reductions in annual stream discharge. These findings indicate that the hydrologic response of mountain catchments to atmospheric warming and reduced snowfall may substantially vary across elevations with differing soil and regolith properties, a relationship not typically accounted for in approaches relying on space-for-time substitution. An additional implication of our results is that model simulations of annual stream discharge in response to snowfall-to-rainfall transitions may be relatively uncertain for study areas where subsurface properties are not well constrained.
The Chern–Simons invariants for the double of a compression body

Given a 3-manifold that can be written as the double of a compression body, we compute the Chern‐Simons critical values for arbitrary compact connected structure groups. We also show that the moduli space of flat connections is connected when there are no reducibles.
Foreign Trade and Investment: Firm-level Perspectives

This Economica Coase Lecture reviews research that has revolutionized the field of international trade and foreign direct investment. It explains the motivation behind the development of new analytical frameworks, the nature of these frameworks, and the empirical studies that sprouted from them.
Pragmatics and intensional logic

The word ‘pragmatics’ was used in Morris [1] for that branch of philosophy of language which involves, besides linguistic expressions and the objects to which they refer, also the users of the expressions and the possible contexts of use. The other two branches, syntax and semantics, dealing respectively with expressions alone and expressions together with their reference, had already been extensively developed by the time at which Morris wrote, the former by a number of authors and the latter in Tarski [1].
Matrix theory for minimal trellises

Trellises provide a graphical representation for the row space of a matrix. The product construction of Kschischang and Sorokine builds minimal conventional trellises from matrices in minimal span form. Koetter and Vardy showed that minimal tail-biting trellises can be obtained by applying the product construction to submatrices of a characteristic matrix. We introduce the unique reduced minimal span form of a matrix and we obtain an expression for the unique reduced characteristic matrix. Among new properties of characteristic matrices we prove that characteristic matrices are in duality if and only if they have orthogonal column spaces, and that the transpose of a characteristic matrix is again a characteristic matrix if and only if the characteristic matrix is reduced. These properties have clear interpretations for the unwrapped unit memory convolutional code of a tail-biting trellis, they explain the duality for the class of Koetter and Vardy trellises, and they give a natural relation between the characteristic matrix based Koetter–Vardy construction and the displacement matrix based Nori–Shankar construction. For a pair of reduced characteristic matrices in duality, one is lexicographically first in a forward direction and the other is lexicographically first in the reverse direction. This confirms a conjecture by Koetter and Vardy after taking into account the different directions for the lexicographical ordering.
Occurrence typing modulo theories

We present a new type system combining occurrence typing---a technique previously used to type check programs in dynamically-typed languages such as Racket, Clojure, and JavaScript---with dependent refinement types. We demonstrate that the addition of refinement types allows the integration of arbitrary solver-backed reasoning about logical propositions from external theories. By building on occurrence typing, we can add our enriched type system as a natural extension of Typed Racket, reusing its core while increasing its expressiveness. The result is a well-tested type system with a conservative, decidable core in which types may depend on a small but extensible set of program terms. In addition to describing our design, we present the following: a formal model and proof of correctness; a strategy for integrating new theories, with specific examples including linear arithmetic and bitvectors; and an evaluation in the context of the full Typed Racket implementation. Specifically, we take safe vector operations as a case study, examining all vector accesses in a 56,000 line corpus of Typed Racket programs. Our system is able to prove that 50% of these are safe with no new annotations, and with a few annotations and modifications we capture more than 70%.
Traficando con hombres: la antropología de la masculinidad

La antropologia siempre ha tenido que ver con hombres hablando con hombres sobre hombres, no obstante es bastante reciente el que dentro de la disciplina unos pocos hayan realmente examinado a los hombres como hombres. Este articulo explora el como entienden, utilizan y discuten los antropologos la categoria de masculinidad mediante la revision de analisis recientes sobre los hombres como sujetos que tienen genero a la vez que lo otorgan. Se comienza con las descripciones de cuatro formas distintas de definicion y tratamiento de la masculinidad en la antropologia, y se presta atencion especial a las relaciones de diferencia, desigualdad, y mujeres con el estudio antropologico de las masculinidades, incluida la curiosa omision de la teoria feminista por patie de numerosos antropologos estudiosos de lo varonil. Los temas especificos que se discuten abarcan las diversas economias culturales de la masculinidad, la nocion de regiones culturales en relacion a las imagenes de hombria, amistad masculina, machismo, corporalidad masculina, violencia, poder, y fisuras sexuales.
Selectivity Effects in Bimetallic Catalysis

An emerging area of homogeneous catalysis is the use of catalysts featuring two closely associated metal sites. This approach complements the traditional focus on single-site catalysts and makes available new parameters with which to optimize catalytic behavior. Single-site catalysts are optimized through changing 1) the identity of the metal, and 2) the steric and electronic properties of the ligands. Bimetallic catalysts introduce new optimization parameters such as 3) catalyst nuclearity (mononuclear vs. binuclear), and 4) bimetallic pairing (relative compatibility of two metal sites). In order to harness these new optimization parameters in developing systems, it is necessary to first understand the origin of bimetallic selectivity effects that already have been documented. This Concept article highlights bimetallic effects on the chemo-, regio-, and stereoselectivity of catalytic transformations, using selected case studies from the recent literature as illustrative examples.
FEMORAL TAPEROSIS: A CONSEQUENCE OF MODULAR TOTAL HIP DESIGNS

Corrosion at metal/metal modular interfaces in total hip arthroplasty was first described in the early 19909s, and the susceptibility of modular tapers to mechanically assisted crevice corrosion (MACC), a combination of fretting and crevice corrosion, was subsequently introduced. Since that time, there have been numerous reports of corrosion at this taper interface, documented primarily in retrieval studies or in rare cases of catastrophic failure. We have reported that fretting corrosion at the modular taper may produce soluble and particulate debris that can migrate locally or systemically, and more recently reported that this process can cause an adverse local tissue reaction. Based on the type of tissue reaction and the presence of elevated serum metal ion levels, this process appears quite similar to adverse local tissue reactions secondary to metal-on-metal bearing surfaces. While modularity in THR has demonstrable clinical benefits, modular junctions increase the risk of corrosion and the types of adverse soft tissue reactions seen in patients with accelerated metal release from metal-on-metal bearing THRs.
γ-AApeptides: Design, Structure, and Applications

ConspectusThe development of sequence-specific peptidomimetics has led to a variety of fascinating discoveries in chemical biology. Many peptidomimetics can mimic primary, secondary, and even tertiary structure of peptides and proteins, and because of their unnatural backbones, they also possess significantly enhanced resistance to enzymatic hydrolysis, improved bioavailability, and chemodiversity. It is known that peptide nucleic acids (PNAs) are peptidic sequences developed for the mimicry of nucleic acids; however, their unique backbone as the molecular scaffold of peptidomimetics to mimic structure and function of bioactive peptides has not been investigated systematically. As such, we recently developed a new class of peptidomimetics, “γ-AApeptides”, based on the chiral γ-PNA backbone. They are termed γ-AApeptides because they are the oligomers of γ-substituted-N-acylated-N-aminoethyl amino acids. Similar to other classes of peptidomimetics, γ-AApeptides are also resistant to proteolytic degradation ...
The Fall in Chinese Poverty: Issues of Measurement, Incidence and Cause

Honoring Keith Griffinâ€™s more than 40 years of fundamental contributions to the discipline of economics, the papers in this volume reflect his deep commitment to advancing the well-being of the worldâ€™s poor majority and his unflinching willingness to question conventional wisdom as to how this should be done.
Effects From a Farmer-led Collective Action Water Management Plan on Irrigators in Kansas

Depleting groundwater in regions of Kansas over the High Plains Aquifer have become areas of critical concern. Irrigators in Sheridan County, Kansas voted to impose restrictions on themselves by forming a Local Enhanced Management Area (LEMA) in an effort to self-regulate their water use. We estimate the short term production decision changes due to the collective action water use restriction whereby a difference-in-differences model and fixed effects regression. We compare differences between restricted irrigators to those located within five miles of the LEMA water restriction boundary. Our estimates indicate that the management plan was successful at reducing groundwater use and we find the greatest response to the water restriction policy at the intensive margin. This implies irrigators primarily responded by reducing the number of applied inches of water per acre; however, we also find that irrigators subject to the water use restriction responded by shrinking the total number of irrigated acres. In general, we find irrigators adjusted water use primarily by reducing irrigation intensity on corn or soybean, the main crops for this region, rather than switching to different crops.
Stereoselective Glucuronidation of Bupropion Metabolites In Vitro and In Vivo.

Bupropion is a widely used antidepressant and smoking cessation aid in addition to being one of two US Food and Drug Administration–recommended probe substrates for evaluation of cytochrome P450 2B6 activity. Racemic bupropion undergoes oxidative and reductive metabolism, producing a complex profile of pharmacologically active metabolites with relatively little known about the mechanisms underlying their elimination. A liquid chromatography-tandem mass spectrometry assay was developed to simultaneously separate and detect glucuronide metabolites of (R,R)- and (S,S)-hydroxybupropion, (R,R)- and (S,S)-hydrobupropion (threo) and (S,R)- and (R,S)-hydrobupropion (erythro), in human urine and liver subcellular fractions to begin exploring mechanisms underlying enantioselective metabolism and elimination of bupropion metabolites. Human liver microsomal data revealed marked glucuronidation stereoselectivity [Clint, 11.4 versus 4.3 µl/min per milligram for the formation of (R,R)- and (S,S)-hydroxybupropion glucuronide; and Clmax, 7.7 versus 1.1 µl/min per milligram for the formation of (R,R)- and (S,S)-hydrobupropion glucuronide], in concurrence with observed enantioselective urinary elimination of bupropion glucuronide conjugates. Approximately 10% of the administered bupropion dose was recovered in the urine as metabolites with glucuronide metabolites, accounting for approximately 40%, 15%, and 7% of the total excreted hydroxybupropion, erythro-hydrobupropion, and threo-hydrobupropion, respectively. Elimination pathways were further characterized using an expressed UDP-glucuronosyl transferase (UGT) panel with bupropion enantiomers (both individual and racemic) as substrates. UGT2B7 catalyzed the stereoselective formation of glucuronides of hydroxybupropion, (S,S)-hydrobupropion, (S,R)- and (R,S)-hydrobupropion; UGT1A9 catalyzed the formation of (R,R)-hydrobupropion glucuronide. These data systematically describe the metabolic pathways underlying bupropion metabolite disposition and significantly expand our knowledge of potential contributors to the interindividual and intraindividual variability in therapeutic and toxic effects of bupropion in humans.