cssi/SciSciGPT-SciSciNet huggingface dataset:
Poverty and distributional impact of gas price hike in Armenia

Armenia meets about 75 percent of its energy needs through imports, with natural gas imports from Russia accounting for about 80 percent of total energy imports and 60 percent of total primary energy supply. Because of high dependence on imported energy, Armenia is vulnerable to external energy price shocks, which are often beyond the control of its policymakers. A most recent case in point was the 2010 Russian gas tariff increase, which led to a nearly 40 percent increase in the retail gas price for residential consumers. Coming on the heels of the global economic recession that hit Armenia's economy hard, the price hike amplified the impact on households that rely primarily on gas for heating and cooking. Using aggregate energy consumption data and a nationally representative household survey immediately before the crisis, this paper provides an overview of household energy consumption patterns, highlights Armenia's energy vulnerability, and estimates the direct poverty and distributional impacts of the increase in the cost of imported gas. The analysis shows that the gas price hike resulted in a significant increase in energy expenditures, with disproportionately higher impact on the poor and vulnerable households. The paper concludes with a discussion on the effectiveness of the mitigation measures employed by the Government of Armenia.
Development of ceramic pre-combustion chamber for the automotive diesel engine

A precombustion chamber (hot plug) made of the silicon nitride ceramics has been developed. The hot plug constitutes a component of the combustion chamber of swirl chamber diesel engines. It is subjected to the severest thermal load of all the diesel engine operating components. Unlike metal hot plugs, the ceramic hot plug application requires a unique design approach to meet the ability of the ceramic materials. That is, the soft engine mounting is necessary to avoid the concentration of mechanical stress resulting from the high Young's modulus of the ceramic and control of temperature distribution is also required to reduce thermal stress. Due to the heat insulating construction, the ceramic hot plug permits the combustion performance to be improved at a low speed and load, resulting in improved noise, startability, and hc emission. In additional the ceramic hot plugs are already being produced for diesel passenger car.
Linear-Time Approximation Algorithms for Computing Numerical Summation with Provably Small Errors

Given a multiset X={x1,. . .,xn} of real numbers, the floating-point set summation problem asks for Sn=x1 + . . . + xn. Let $E^*_n$ denote the minimum worst-case error over all possible orderings of evaluating Sn. We prove that if X has both positive and negative numbers, it is NP-hard to compute Sn with the worst-case error equal to $E^*_n$. We then give the first known polynomial-time approximation algorithm that has a provably small error for arbitrary X. Our algorithm incurs a worst-case error at most $2(\lceil\log(n-1)\rceil+1)E^*_n$. (All logarithms log in this paper are base 2.) After X is sorted, it runs in O(n) time. For the case where X is either all positive or all negative, we give another approximation algorithm with a worst-case error at most $\lceil\log\log n\rceil E^*_n$. Even for unsorted X, this algorithm runs in O(n) time. Previously, the best linear-time approximation algorithm had a worst-case error at most $\lceil\log n\rceil E^*_n$, while $E^*_n$ was known to be attainable in O(n log n) time using Huffman coding.
Fluctuating-surface-current formulation of radiative heat transfer for arbitrary geometries

We describe a fluctuating-surface-current formulation of radiative heat transfer, applicable to arbitrary geometries in both the near and far field, that directly exploits efficient and sophisticated techniques from the boundary-element method. We validate as well as extend previous results for spheres and cylinders, and also compute the heat transfer in a more complicated geometry consisting of two interlocked rings. Finally, we demonstrate how this method can be adapted to compute the spatial distribution of heat flux on the surfaces of the bodies.
Accurate Delayed-Neutron Parameter Measurements in a Heavy-Water Reactor

The familiar rod-drop method for determining delayed-neutron parameters has been refined with new techniques of data collection, analysis, and correction. Values for a highly enriched uranium, heav...
The Chiral Magnetic Effect and Axial Anomalies

We give an elementary derivation of the chiral magnetic effect based on a strong magnetic field lowest-Landau-level projection in conjunction with the well-known axial anomalies in two- and four-dimensional space-time. The argument is general, based on a Schur decomposition of the Dirac operator. In the dimensionally reduced theory, the chiral magnetic effect is directly related to the relativistic form of the Peierls instability, leading to a spiral form of the condensate, the chiral magnetic spiral. We then discuss the competition between spin projection, due to a strong magnetic field, and chirality projection, due to an instanton, for light fermions in QCD and QED. The resulting asymmetric distortion of the zero modes and near-zero modes is another aspect of the chiral magnetic effect.
The coherent state variational algorithm: (II). Implementation and testing☆

Abstract The coherent state variational algorithm provides a method for solving the large-N limit of non-abelian gauge theories. An implementation of this algorithm, capable of minimizing the large-N effective action and computing meson and glueball spectra, has recently been completed. Hamiltonian or euclidean formulations of lattice gauge theories, in any dimension, may be studied. Bose or Fermi fundamental representation matter fields may be included. This paper discusses the design and testing of this implementation. The method involves explicit manipulation of expectation values of physical operators and may be applied directly in infinite volume. The error introduced by the truncation of the set of physical observables (necessary to obtain a finite procedure) is studied by applying the algorithm to a variety of exactly soluble model theories. These include φ4 scalar field theories, ( ψ ψ) 2 fermion theories, 2-dimensional euclidean pure gauge theory, and 1 + 1 dimensional QCD. Modest size calculations are shown to yield accurate results, even in theories possessing asymptotic freedom, spontaneous symmetry breaking, or large-N phase transitions.
Bias from Nonresponse

Nonresponse bias results when some members of the intended study population fail to provide required data (the nonresponders), and when those who respond are not representative of the entire study population. Keywords: bias; nonresponse; bias in case–control studies; bias in cohort studies
The Schorr-Waite graph marking algorithm

An explanation is given of the Schorr-Waite algorithm for marking all nodes of a directed graph that are reachable from one given node, using the axiomatic method.
Aging and the depth of binocular rivalry suppression

Two experiments were designed to examine the effect of aging on the strength of binocular rivalry suppression. To produce rivalry, orthogonally oriented sine-wave luminance gratings were presented dichoptically. The observers were then required either to discriminate the spatial location of a probe spot presented to the dominant or suppressed eye's view or to detect the presence or absence of the probe. The observers in the younger and older age groups exhibited typical rivalry suppression for both tasks (i.e., the probe was more difficult to detect or discriminate when presented to the suppressed eye), but the magnitude of the suppression was significantly larger in the older observers. This increased suppression that accompanies aging can be explained by a reduction in the inhibition produced by the binocular matching circuitry of S. R. Lehky and R. Blake's (1991) model.
Axotomy‐induced target disconnection promotes an additional death mechanism involved in motoneuron degeneration in amyotrophic lateral sclerosis transgenic mice

The target disconnection theory of amyotrophic lateral sclerosis (ALS) pathogenesis suggests that disease onset is initiated by a peripheral pathological event resulting in neuromuscular junction loss and motoneuron (MN) degeneration. Presymptomatic mSOD1G93A mouse facial MN (FMN) are more susceptible to axotomy-induced cell death than wild-type (WT) FMN, which suggests additional CNS pathology. We have previously determined that the mSOD1 molecular response to facial nerve axotomy is phenotypically regenerative and indistinguishable from WT, whereas the surrounding microenvironment shows significant dysregulation in the mSOD1 facial nucleus. To elucidate the mechanisms underlying the enhanced mSOD1 FMN loss after axotomy, we superimposed the facial nerve axotomy model on presymptomatic mSOD1 mice and investigated gene expression for death receptor pathways after target disconnection by axotomy vs. disease progression. We determined that the TNFR1 death receptor pathway is involved in axotomy-induced FMN death in WT and is partially responsible for the mSOD1 FMN death. In contrast, an inherent mSOD1 CNS pathology resulted in a suppressed glial reaction and an upregulation in the Fas death pathway after target disconnection. We propose that the dysregulated mSOD1 glia fail to provide support the injured MN, leading to Fas-induced FMN death. Finally, we demonstrate that, during disease progression, the mSOD1 facial nucleus displays target disconnection-induced gene expression changes that mirror those induced by axotomy. This validates the use of axotomy as an investigative tool in understanding the role of peripheral target disconnection in the pathogenesis of ALS. J. Comp. Neurol. 522:2349–2376, 2014. © 2014 Wiley Periodicals, Inc.
Image Analysis Of Food Microstructure

INTRODUCTION STEREOLOGY The need for stereology Unfolding size distribution Volume fraction Surface area Design of experiments Topological properties Other stereological techniques IMAGE ACQUISITION Scanners Digital cameras Scanning microscopes File formats Color adjustment Color space coordinates Color channels Optimum image contrast Removing noise Nonuniform illumination Image distortion and focus PROCESSING AND ENHANCEMENT Improving local contrast Image sharpening Rank-based filters Edge finding Texture Directionality Finding features in images Image combinations Thresholding Automatic threshold settings using the histogram Automatic threshold settings using the image Other thresholding approaches Color image thresholding Manual marking BINARY IMAGES Erosion and dilation The Euclidean distance map Separating touching features Boolean combinations Using grids for measurement Using markers to select features Combined Boolean operations Region outlines as selection criteria Skeletonization Fiber images Skeletons and feature shape Measuring distance and location with the EDM Summary FEATURE MEASUREMENT Counting Size measurement Size distributions Comparisons Edge correction Brightness and color measurement Location Gradients Shape Identification Conclusions COLOR PLATES (insert)
PlanGraph: An Agent-Based Computational Model for Handling Vagueness in Human-GIS Communication of Spatial Concepts

A fundamental challenge in developing a usable conversational interface for Geographic Information Systems (GIS) is effective communication of spatial concepts in natural language, which are commonly vague in meaning. This paper presents a design of an agent-based computational model, PlanGraph. This model is able to help the GIS to keep track of the dynamic human-GIS communication context and enable the GIS to understand the meaning of a vague spatial concept under constrains of the dynamic context.
Convex gradient optimization for increased spatiotemporal resolution and improved accuracy in phase contrast MRI

Purpose: To evaluate convex gradient optimization (CVX) for increased spatiotemporal resolution and improved accuracy for phase-contrast MRI (PC-MRI). Methods: A conventional flow-compensated and flowencoded (FCFE) PC-MRI sequence was compared with a CVX PC-MRI sequence using numerical simulations, flow phantom experiments, and in vivo experiments. Flow measurements within the ascending aorta, main pulmonary artery, and right/ left pulmonary arteries of normal volunteers (N ¼ 10) were acquired at 3T and analyzed using a conventional FCFE sequence and a CVX sequence with either higher spatial resolution or higher temporal resolution. All sequences mitigated chemical shift–induced phase errors and used equivalent breath-hold durations. Results: Chemical shift–optimized PC-MRI has increased sequence efficiency when using CVX, which can provide either higher spatial or higher temporal resolution compared with conventional FCFE PC-MRI. Numerical simulations, flow phantom experiments, and in vivo experiments indicate that CVX measurements of total flow and peak velocity are increased and more accurate when compared with FCFE. Conclusion: CVX PC-MRI increases sequence efficiency while reducing chemical shift–induced phase errors. This can be used to provide either higher spatial or higher temporal resolution than conventional chemical shift–mitigated PC-MRI methods to provide more accurate measurements of blood flow and peak velocity. Magn Reson Med 72:1552–1564, 2014. V C 2013 Wiley Periodicals, Inc.
How has epoprostenol changed the outcome for patients with pulmonary arterial hypertension

Summary Aims: Pulmonary arterial hypertension (PAH), characterized by increased pulmonary vascular resistance and pulmonary artery pressure, is a significant cause of morbidity and mortality in children and adults. Prior to 1995, there were no approved therapies for PAH. Materials and Methods: Review of the clinical drug development of epoprostenol (synthetic prostacyclin) for the treatment of PAH. Results: Based on the results of a phase 2 and one phase 3 trial carried out between 1987 and 1992 in adult patients with PAH, epoprostenol was approved for the treatment of severe idiopathic PAH in 1995. Continuous intravenous infusion 24/7 of epoprotenol improved exercise capacity, hemodynamic parameters, functional capacity and survival. Epoprostenol was subsequently shown to be safe and efficacious in PAH associated with the scleroderma spectrum of disease and has now been utilized in PAH associated with congenital heart disease, HIV, portal hypertension, drugs and toxin and connective tissue diseases. Epoprostenol has also been used in children of all ages with similar safety and efficacy as shown in adult patients. Discussion: Due to the mode of delivery of epoprostenol, i.e. continuous intravenous infusion 24/7 via an indwelling central venous line, there are significant side effects than can occur with its use, e.g. bacteremia, sepsis, thromboembolic events, that can be fatal. Furthermore, there is significant variability in the optimal dose in both children and adult patients. It remains unclear why there is such dose variability between patients to achieve optimal efficacy. Furthermore, its mechanism(s) of action remain unclear.
THE VANISHING BEQUEST TAX: THE COMPARATIVE EVOLUTION OF BEQUEST TAXATION IN HISTORICAL PERSPECTIVE

Bequest tax revenues have been declining in OECD countries for at least 70 years. We propose an explanation that is based on a dynamic politico-economic model where the evolution of bequest taxation is determined by wealth inequality. Since economic development induces a growing role of labor income and thus a reduction of wealth inequality, bequest taxation is reduced over time. The model also embeds a process of structural reallocation from agriculture to manufacturing and a consequent shift of the tax base from easy-to-tax land to hard-to-tax capital. This process implies a lower tax level and slower equalization-induced tax reduction, the higher is the tax avoidance rate and the less developed is the economy. The introduction of franchise restrictions which are gradually lifted over time allows the hump-shaped long-term evolution of bequest taxation to be reproduced starting from the nineteenth century for those countries that are now modern industrial democracies. The evolution of political institutions also helps to explain the discrepancies currently observed between tax systems in developed and underdeveloped countries.
Cascaded star: a hyper-dimensional model for a data warehouse

A data warehouse is defined as subject-oriented, integrated, time-variant and nonvolatile collection of data. Often, the data representing different subjects is multi-dimensional in nature, where each dimension of each subject could again be multi-dimensional. We refer to this as hyper-dimensional nature of data. Traditional multi-dimensional data models (e.g., the star schema) cannot adequately model these data. This is because, a star schema models one single multi-dimensional subject, hence a complex query crossing different subjects at different dimensional levels has to be specified as multiple queries and the results of each query must be composed together manually. In this paper, we present a novel data model, called the cascaded star model, to model hyper-dimensional data, and propose the cascaded OLAP (COLAP) operations that enable ad-hoc specification of queries that encompass multiple stars. Specifically, our COALP operations include cascaded-roll-up, cascaded-drill-down, cascaded-slice, cascaded-dice and MCUBE. We show that COLAP can be represented by the relational algebra to demonstrate that the cascaded star can be built on top of the traditional star schema framework.
Intelligent workstation agents and unstructured workstation data

Summary form only given. Many researchers envision a future of intelligent, personalized agents in their computer workstations. These agents could provide a variety of personalized assistance helping to manage email, schedule meetings, gather and summarize relevant information, track progress of various projects, etc. Perhaps the greatest barrier to creating such intelligent agents is that the data observable to such an agent is unstructured and difficult to automatically interpret - it includes unstructured workstation files (text, images, and other formats), email, calendar entries, Web accesses, etc. This paper discusses current research toward such intelligent workstation agents, and in particular toward making this unstructured data understandable to computer agents. This research is being conducted as part of a multiuniversity research effort on intelligent personalized assistants.
The effect of food stamps on labor supply: A bivariate selection model

Abstract Although there is a large literature on the effects of U.S. transfer programs on labor supply, this is the first such study of the Food Stamp Program. We model the nonlinearity and nonconvexity of the budget constraint and use maximum-likelihood methods to estimate hours- of-work functions for female heads of household, the largest recipient group in the program. We also model the joint response to AFDC and Food Stamps and we account for the existence of a significant number of eligible households who do not participate in the programs. A three- equation, bivariate selection model is estimated on a sample of eligible households with maximum likelihood.
Long‐term carbon loss and recovery following selective logging in Amazon forests

[1] Amazon deforestation contributes significantly to global carbon (C) emissions. In comparison, the contribution from selective logging to atmospheric CO2 emissions, and its impact on regional C dynamics, is highly uncertain. Using a new geographically based modeling approach in combination with high resolution remote sensing data from 1999 to 2002, we estimate that C emissions were 0.04–0.05 Pg C yr−1 due to selective logging from a ∼2,664,960 km2 region of the Brazilian Amazon. Selective logging was responsible for 15–19% higher carbon emissions than reported from deforestation (clear-cutting) alone. Our simulations indicated that forest carbon lost via selective logging lasts two to three decades following harvest, and that the original live biomass takes up to a century to recover, if the forests are not subsequently cleared. The two- to three-decade loss of carbon results from the biomass damaged by logging activities, including leaves, wood, and roots, estimated to be 89.1 Tg C yr−1 from 1999 to 2002 over the study region, leaving 70.0 Tg C yr−1 and 7.9 Tg C yr−1 to accumulate as coarse woody debris and soil C, respectively. While avoided deforestation is central to crediting rain forest nations for reduced carbon emissions, the extent and intensity of selective logging are also critical to determining carbon emissions in the context of Reduced Emissions from Deforestation and Forest Degradation (REDD). We show that a combination of automated high-resolution satellite monitoring and detailed forest C modeling can yield spatially explicit estimates of harvest-related C losses and subsequent recovery in support of REDD and other international carbon market mechanisms.
On the approximability of covering points by lines and related problems

Given a set P of n points in the plane, Covering Points by Lines is the problem of finding a minimum-cardinality set L of lines such that every point p ? P is incident to some line ? ? L . As a geometric variant of Set Cover, Covering Points by Lines is still NP-hard. Moreover, it has been proved to be APX-hard, and hence does not admit any polynomial-time approximation scheme unless P = NP. In contrast to the small constant approximation lower bound implied by APX-hardness, the current best approximation ratio for Covering Points by Lines is still O ( log ? n ) , namely the ratio achieved by the greedy algorithm for Set Cover.In this paper, we give a lower bound of ? ( log ? n ) on the approximation ratio of the greedy algorithm for Covering Points by Lines. We also study several related problems including Maximum Point Coverage by Lines, Minimum-Link Covering Tour, Minimum-Link Spanning Tour, and Min-Max-Turn Hamiltonian Tour. We show that all these problems are either APX-hard or at least NP-hard. In particular, our proof of APX-hardness of Min-Max-Turn Hamiltonian Tour sheds light on the difficulty of Bounded-Turn-Minimum-Length Hamiltonian Tour, a problem proposed by Aggarwal et al. at SODA 1997.
Subsurface charge accumulation imaging of a quantum Hall liquid

The unusual properties of two-dimensional electron systems that give rise to the quantum Hall effect have prompted the development of new microscopic models for electrical conduction1,2,3,4,5,6. The bulk properties of the quantum Hall effect have also been studied experimentally using a variety of probes including transport7,8, photoluminescence9,10, magnetization11 and capacitance12,13 measurements. However, the fact that two-dimensional electron systems typically exist some distance (about 1,000 A) beneath the surface of the host semiconductor has presented an important obstacle to more direct measurements of microscopic electronic structure in the quantum Hall regime. Here we introduce a cryogenic scanning-probe technique—‘subsurface charge accumulation’ imaging—that permits very high resolution examination of systems of mobile electrons inside materials. We use this technique to image directly the nanometre-scale electronic structures that exist in the quantum Hall regime.
The impact of environmental performance rating and disclosure: an empirical analysis of perceptions by polluting firms' managers in China

Environmental performance rating and disclosure has emerged as a substitute or complement for traditional pollution regulation, especially in developing countries. Using data from China's Green Watch program, this study extends previous research on performance rating and disclosure by considering firms' perceptions of public and market responses to their ratings. The results suggest that the Green Watch has significantly increased market and stakeholder pressures on managers to improve their firms environmental performance. More specifically, controlling for the characteristics of locations, firms, and individual managers, the analysis finds that firms with better ratings perceive positive impacts on market competitiveness, overall market value, and relationships with different stakeholders, while the firms with bad ratings are more likely to perceive deterioration. Among these factors, managers perceive a more active role for markets than for stakeholder relations.
Introduction to Cosmic F- and D-Strings

In these lectures I discuss the possibility that superstrings of cosmic length might exist and be observable. I first review the original idea of cosmic strings arising as gauge theory solitons, and discuss in particular their network properties and the observational bounds that rule out cosmic strings as the principal origin of structure in our universe. I then consider cosmic superstrings, including the ‘fundamental’ F-strings and also D-strings and strings arising from wrapped branes. I discuss the conditions under which these will exist and be observable, and ways in which different kinds of string might be distinguished. We will see that each of these issues is model-dependent, but that some of the simplest models of inflation in string theory do lead to cosmic superstrings. Moreover, these could be the first objects seen in gravitational wave astronomy, and might have distinctive network properties.
Most Relevant Explanation: properties, algorithms, and evaluations

Most Relevant Explanation (MRE) is a method for finding multivariate explanations for given evidence in Bayesian networks [12]. This paper studies the theoretical properties of MRE and develops an algorithm for finding multiple top MRE solutions. Our study shows that MRE relies on an implicit soft relevance measure in automatically identifying the most relevant target variables and pruning less relevant variables from an explanation. The soft measure also enables MRE to capture the intuitive phenomenon of explaining away encoded in Bayesian networks. Furthermore, our study shows that the solution space of MRE has a special lattice structure which yields interesting dominance relations among the solutions. A K-MRE algorithm based on these dominance relations is developed for generating a set of top solutions that are more representative. Our empirical results show that MRE methods are promising approaches for explanation in Bayesian networks.
THE CHANGE IN NEAR-ECLIPTIC ZODIACAL LIGHT BRIGHTNESS WITH HELIOCENTRIC DISTANCE

Background starlight observed by the Pioneer 10 Imaging Photopolarimeter from beyond the asteroid belt is used to isolate zodiacal light in Pioneer observations at heliocentric distances R between 1 and 3 AU. Near—ecliptic zodiacal light brightness data in the range 65° to l80° elongation e are used to depict changes in the shape of the zodiacal light with e and R and are compared to the corresponding views seen from the Earth and from the Helios 1 and 2 spacecraft.
TMAH wet etching of silicon micro- and nano-fins for selective sidewall epitaxy of III-Nitride semiconductors

We describe wet etch experiments to form silicon micro- and nano-fins, with (111)-plane sidewall facets, to be used in selective epitaxy of III-Nitride semiconductors. Starting material was (110)-oriented silicon wafers. Silicon dioxide is used for producing a hard mask and patterned using photo- and electron-beam lithography for micro- and nano-fins, respectively. Wet etching to produce silicon fins was carried out using tetramethyl ammonium hydroxide (TMAH) diluted with isopropyl alcohol (TPA). We experimented with silicon doped TMAH/IPA solution, using a sacrificial wafer, and with surfactant (Triton X-100). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to determine the morphology including surface roughness of the area between fins and etching rate of silicon. By controlling the etching time, temperature, percentage of IPA and concentration of Triton X-100 we obtain good surface morphology on both (111) and (110) planes. Nanofins as small as 30 nm in width and ∼ 250 nm in height are prepared, with corresponding aspect ratio of ∼ 8:1.
A proximal method for composite minimization

We consider minimization of functions that are compositions of convex or prox-regular functions (possibly extended-valued) with smooth vector functions. A wide variety of important optimization problems fall into this framework. We describe an algorithmic framework based on a subproblem constructed from a linearized approximation to the objective and a regularization term. Properties of local solutions of this subproblem underlie both a global convergence result and an identification property of the active manifold containing the solution of the original problem. Preliminary computational results on both convex and nonconvex examples are promising.
Enzymes for chemical synthesis

New catalytic synthetic methods in organic chemistry that satisfy increasingly stringent environmental constraints are in great demand by the pharmaceutical and chemical industries. In addition, novel catalytic procedures are necessary to produce the emerging classes of organic compounds that are becoming the targets of molecular and biomedical research. Enzyme-catalysed chemical transformations are now widely recognized as practical alternatives to traditional (non-biological) organic synthesis, and as convenient solutions to certain intractable synthetic problems.
Reducing Tile Complexity for the Self-assembly of Scaled Shapes Through Temperature Programming

This paper concerns the self-assembly of scaled-up versions of arbitrary finite shapes. We work in the multiple temperature model that was introduced by Aggarwal, Cheng, Goldwasser, Kao, and Schweller (Complexities for Generalized Models of Self-Assembly, SIAM J. Comput. 2005). The multiple temperature model is a natural generalization of Winfree’s abstract tile assembly model, where the temperature of a tile system is allowed to be shifted up and down as self-assembly proceeds. We first exhibit two constant-size tile sets in which scaled-up versions of arbitrary shapes self-assemble. Our first tile set has the property that each scaled shape self-assembles via an asymptotically “Kolmogorov-optimum” temperature sequence but the scaling factor grows with the size of the shape being assembled. In contrast, our second tile set assembles each scaled shape via a temperature sequence whose length is proportional to the number of points in the shape but the scaling factor is a constant independent of the shape being assembled. We then show that there is no constant-size tile set that can uniquely assemble an arbitrary (non-scaled, connected) shape in the multiple temperature model, i.e., the scaling is necessary for self-assembly. This answers an open question of Kao and Schweller (Proceedings of the 17th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA 2006), pp. 571–580, 2006), who asked whether such a tile set exists.
On the intermediate integral for Monge-Ampère equations

Goursat showed that in the presence of an intermediate integral, the problem of solving a second-order Monge-Ampere equation can be reduced to solving a first-order equation, in the sense that the generic solution of the first-order equation will also be a solution of the original equation. An attempt by Hermann to give a rigorous proof of this fact contains an error; we show that there exists an essentially unique counterexample to Hermann's assertion and state and prove a correct theorem.
Application of design of experiments (DoE) optimization to the one-pot synthesis of 4,6-dihydropteridinones

A design of experiments (DoE) analysis of a tandem SnAr-amidation cyclization reaction between 4-chloropyrimidin-5-amine and (S)-N-methylalanine to form (S)-7,8-dimethyl-7,8-dihydropteridin-6(5H)-one is reported. Five reaction variables were optimized using DoE and conversion was improved from 26% to 74%, with a significant reduction in reaction time while retaining high optical purity. The optimized conditions were applied to the synthesis of a wide variety of analogs and the expanded reaction substrate scope included a variety of amino acids and pyrimidines. Products were obtained in isolated yields up to 95% and enantiomeric excess as high as 98%.
Rising Family Income Inequality: The Importance of Sorting

The distribution of family income reflects the distribution of personal income and the composition of families. We develop a non-parametric measure of the impact that changes in family income relationships have on the distribution of family income. Using data from Annual Social and Economic Supplement (the March files) of the Current Population Survey (CPS) (1968-2003), we find that changes in "income sorting" account for more than half of the increase in family income inequality in the United States over the last three decades. Furthermore, income sorting accounts for an even larger share of the growing gap between middle-income and low-income families. Our results demonstrate that understanding inequality of economic well-being requires going beyond labor earnings and other income sources to examine the composition and work behavior of families.
DiPerF: An Automated DIstributed PERformance Testing Framework

We present DiPerF, a distributed performance-testing framework, aimed at simplifying and automating service performance evaluation. DiPerF coordinates a pool of machines that test a target service, collects and aggregates performance metrics, and generates performance statistics. The aggregate data collected provide information on service throughput, on service fairness' when serving multiple clients concurrently, and on the impact of network latency on service performance. Furthermore, using this data, it is possible to build predictive models that estimate a service performance given the service load. We have tested DiPerF on 100+machines on two testbeds, Grid3 and PlanetLab, and explored the performance of job submission services (pre-WS GRAM and WS GRAM) included with Globus Toolkit/spl reg/ 3.2.
The Kuiper Belt and Other Debris Disks

We discuss the current knowledge of the solar system, focusing on bodies in the outer regions, on the information they provide concerning solar system formation, and on the possible relationships that may exist between our system and the debris disks of other stars. Beyond the domains of the terrestrial and giant planets, the comets in the Kuiper belt and the Oort cloud preserve some of our most pristine materials. The Kuiper belt, in particular, is a collisional dust source and a scientific bridge to the dusty “debris disks” observed around many nearby main-sequence stars. Study of the solar system provides a level of detail that we cannot discern in the distant disks while observations of the disks may help to set the solar system in proper context.
Tail asymptotics for delay in a half-loaded GI/GI/2 queue with heavy-tailed job sizes

We obtain asymptotic bounds for the tail distribution of steady-state waiting time in a two-server queue where each server processes incoming jobs at a rate equal to the rate of their arrivals (that is, the half-loaded regime). The job sizes are taken to be regularly varying. When the incoming jobs have finite variance, there are basically two types of effects that dominate the tail asymptotics. While the quantitative distinction between these two manifests itself only in the slowly varying components, the two effects arise from qualitatively very different phenomena (arrival of one extremely big job or two big jobs). Then there is a phase transition that occurs when the incoming jobs have infinite variance. In that case, only one of these effects dominates the tail asymptotics; the one involving arrival of one extremely big job.
Conflicts of interest in self-regulation : can demutualized exchanges successfully manage them?

The author examines the implications of demutualization of financial exchanges for their roles as self-regulatory organizations. Many regulators and exchanges believe that conflicts of interest increase when exchanges convert to for-profit businesses. Demutualization also changes the nature of an exchange's regulatory role as broker-dealers' ownership interests are reduced. These factors are leading to reduced regulatory roles for exchanges in many jurisdictions. The resulting changes have significant implications for regulation of financial markets, especially as exchanges are the only self-regulating organizations (SROs) in most countries. Major changes in the role of exchanges require a rethinking of the allocation of regulatory functions and the role of self-regulation, as well as stronger mechanisms to mitigate conflicts of interest. Carson looks at the views of both exchanges and regulators on these issues in Asian, European, and North American jurisdictions where major exchanges have converted to for-profit businesses. He finds that views on the conflicts of interest faced by demutualized exchanges vary widely. In addition, the tools and processes used by exchanges and regulators to manage conflicts also differ significantly across jurisdictions. The author concludes that new and greater conflicts result from demutualization and canvasses the regulatory responses in the jurisdictions examined.
Studies of radiative penguin B decays at BaBar

We summarize results on a number of observations of penguin dominated radiative decays of theB meson. Such decays are forbidden at tree level and proceed via electroweak loops. As such they may be sensitive to physics beyond the standard model. The observations have been made at the BaBar experiment at PEP-II, the asymmetricB factory at SLAC.
Disentangling Demand-Enhancing and Trade-Cost Effects of Maximum Residue Regulations

Maximum residue level (MRL) regulations in plant products can create unnecessary trade barriers on one hand and enhance demand via risk mitigation or quality assurance on the other. We stipulate a generalized gravity equation model to disentangle the effects of MRLs on the import demand and foreign exporters' supply. Applying the framework to the MRLs on pesticides imposed by high-income Organization for Economic Co-operation and Development countries, we find that the MRLs jointly enhance the import demand and hinder foreign exporters' supply. In addition, exporters from the less and least developed countries are more constrained by the MRLs than their competitors from the developed world. (JEL F14, Q17)
A Cooperative Savings Game Approach to a Time Sensitive Capacity Allocation and Scheduling Problem

We consider a competitive scheduling setting with arbitrary number of agents each having the option to utilize two parallel resources to satisfy its demand: (i) an in-house resource dedicated to process only the tasks of each specific agent, and (ii) a flexible resource capable of processing all agents' workloads. In a noncooperative setting, each agent would determine how much of its demand it will subcontract to the flexible resource with the objective to deliver its entire demand as quickly as possible subject to the priority rules set by the owner of the flexible resource (i.e., third-party). In this study, we also allow for agents to coalesce with other agents and update their initial subcontracting decisions to attain rescheduling savings. Evidently, a grand coalition of all agents can coordinate to achieve the maximum savings possible, but the resulting schedule may yield individual losses for a subset of agents (which we refer to as “losers”), thus necessitating a transfer payment scheme to distribute the rescheduling savings among the agents in an equitable way. We model the rescheduling interactions among the agents as a cooperative savings game, and propose savings distribution schemes that invoke the core allocation concept.
Sharpness of Second Moment Criteria for Branching and Tree-Indexed Processes

A class of branching processes in varying environments is exhibited which become extinct almost surely even though the means Mn grow fast enough so that \( \sum {M_n^{ - 1}} \) is finite. In fact, such a process is constructed for every offspring distribution of infinite variance, and this establishes the converse of a previously known fact: that if a distribution has finite variance then \( \sum {M_n^{ - 1} = \infty } \) is equivalent to almost sure extinction. This has as an immediate consequence the converse to a theorem on equipolarity of Galton-Watson trees.
Financial Globalization, Financial Crises, and the External Portfolio Structure of Emerging Markets*

We study the transitional dynamics of financial integration in emerging economies using a two-sector model with a collateral constraint on external debt and trading costs incurred by foreign investors. The probability of a financial crisis displays overshooting; it rises sharply initially and then falls sharply, but remains non-zero in the long run. While equity holdings fall permanently, bond holdings initially fall, but rise after the probability of a crisis peaks. Conversely, asset returns and asset prices first rise and then fall. These results are in line with the post-globalization dynamics observed in emerging markets, and the higher frequency of crises that they display.
A Theory of Continuum Economies with Idiosyncratic Shocks and Random Matchings

Many economic models use a continuum of negligible agents to avoid considering one person's effect on aggregate characteristics of the economy. Along with a continuum of agents, these models often incorporate a sequence of independent shocks and random matchings. Despite frequent use of such models, there are still unsolved questions about their mathematical justification. In this paper we construct a discrete time framework, in which major desirable properties of idiosyncratic shocks and random matchings hold. In this framework the agent space constitutes a probability space, and the probability distribution for each agent is replaced by the population distribution. Unlike previous authors, we question the assumption of known identity - the location on the agent space. We assume that the agents only know their previous history - what had happened to them before, - but not their identity. The construction justifies the use of numerous dynamic models of idiosyncratic shocks and random matchings.
Chronic Disease Models

We discuss the need for multidimensional stochastic models of physiological processes to describe the evolving risk of chronic disease over a lifetime. Modifications of that type of model needed to describe different types of risk factor and health effects collected in different longitudinal studies are described. How health processes are “captured” in different longitudinal study designs is discussed, as is the description of the intra-individual dynamics of degenerative processes. The concept of hormesis is introduced as are more standard types of hazard models (Weibull and Gompertz) drawn from reliability theory. Measurements that may be made in molecular epidemiological studies are discussed and issues that they raise for statistical modeling of disease processes reviewed. Methods for analyzing the genetic contributions to chronic disease risks are presented and discussed. Keywords: hazard function; diffusion process; carcinogenesis; cardiovascular disease; risk factors; hormesis; genetics; and molecular epidemiology
Learning preferences for manipulation tasks from online coactive feedback

We consider the problem of learning preferences over trajectories for mobile manipulators such as personal robots and assembly line robots. The preferences we learn are more intricate than simple geometric constraints on trajectories; they are rather governed by the surrounding context of various objects and human interactions in the environment. We propose a coactive online learning framework for teaching preferences in contextually rich environments. The key novelty of our approach lies in the type of feedback expected from the user: the human user does not need to demonstrate optimal trajectories as training data, but merely needs to iteratively provide trajectories that slightly improve over the trajectory currently proposed by the system. We argue that this coactive preference feedback can be more easily elicited than demonstrations of optimal trajectories. Nevertheless, theoretical regret bounds of our algorithm match the asymptotic rates of optimal trajectory algorithms. We implement our algorithm on two high-degree-of-freedom robots, PR2 and Baxter, and present three intuitive mechanisms for providing such incremental feedback. In our experimental evaluation we consider two context rich settings, household chores and grocery store checkout, and show that users are able to train the robot with just a few feedbacks taking only a few minutes.
Benefit Incidence with Incentive Effects, Measurement Errors and Latent Heterogeneity

Empirical studies of tax and benefit incidence routinely ignore behavioral responses and measurement errors. This paper offers an econometric method of estimating the mean benefit withdrawal rate (marginal tax rate) allowing for incentive effects, measurement errors, and correlated latent heterogeneity in incidence. Under the method's identifying assumptions, a feasible instrumental variables estimator corrects for incentive effects and measurement errors, and provides a bound for the true value when there is correlated incidence heterogeneity. A case study for a large cash transfer program in China indicates that past methods of assessing benefit incidence using either nominal official rates or raw tabulations from survey data are deceptive. The program entails a nominal 100 percent benefit withdrawal rate -- a poverty trap. However, the paper finds that the actual rate is much lower, and clearly too low in the light of the literature on optimal income taxation. The paper discusses likely reasons based on the qualitative observations.
Inhibition of sodium channels by D600.

D6OO, an inhibitor of the slow inward Ca++/Na+ current during the plateau phase of the cardiac action potential, also inhibits veratridine-activated fast sodium channels in both cultured heart cells and cultured neuroblastoma cells. The inhibition is competitive with respect to veratridine and is antagonized by Ca++. The KI for D600 in the presence of 1.8 mM Ca++ is approximately 3 µM.
Characterizing Scales of Genetic Recombination and Antibiotic Resistance in Pathogenic Bacteria Using Topological Data Analysis

Pathogenic bacteria present a large disease burden on human health. Control of these pathogens is hampered by rampant lateral gene transfer, whereby pathogenic strains may acquire genes conferring resistance to common antibiotics. Here we introduce tools from topological data analysis to characterize the frequency and scale of lateral gene transfer in bacteria, focusing on a set of pathogens of significant public health relevance. As a case study, we examine the spread of antibiotic resistance in Staphylococcus aureus. Finally, we consider the possible role of the human microbiome as a reservoir for antibiotic resistance genes.
Verifiable transaction atomicity for electronic payment protocols

We study the transaction atomicity problem for designing electronic payment protocols in distributed systems. We observe that the techniques that are used to guarantee transaction atomicity in a database system are not robust enough to guarantee transaction atomicity in an electronic payment system, in which a set of dishonest or malicious participants may exhibit unpredictable behavior and cause arbitrary failures. We present a new concept-verifiable transaction atomicity-for designing electronic payment protocols. We give formal specifications to the verifiable atomic commitment problem. Then we design a robust electronic currency system to meet the specifications and achieve the verifiable transaction atomicity.