cssi/SciSciGPT-SciSciNet huggingface dataset:
Foreign Aid after the Cold War

Foreign aid as it is understood today has its origins in the Cold War. It is largely a product of the ideological confrontation between the United States and the Soviet Union that dominated international politics for forty-five years between 1945 and 1990. It began not as a programme to assist the long-term development of impoverished countries but as a programme to facilitate the short-term economic recovery of Western Europe after the end of the Second World War. The political motivation of what was called the Marshall Plan was to prevent the spread of communism to France and Italy (where the Communist Party was strong), to stabilize conditions in West Germany (and create an attractive alternative to the socio-economic system imposed in East Germany) and to reduce the appeal of socialist policies in the United Kingdom (where the Labour Party enjoyed considerable popularity).
A Dynamic Data Driven Computational Infrastructure for Reliable Computer Simulations

The paper presents an initial study on designing a Dynamic Data Driven (DDD) computational environment to enable reliable and efficient determination of Head Related Transfer Functions (HRTF) for patients with reconstructed ears. The determination involves a synthesis of coordinated experiments and large scale, parallel computer simula- tions. Time limits (one working day), cost of MRI scans, and parallelism in experimental and computer simulations impose the need for a DDD enabling fast and reliable results.
A three-tier framework for intruder information sharing in sensor networks

In sensor networks, an intruder (i.e., compromised node) identified and isolated in one place can be relocated and/or duplicated to other places to continue attacks; hence, detection and isolation of the same intruder or its clones may have to be conducted repeatedly, wasting scarce network resources. Therefore, once an intruder is identified, it should be known to all innocent nodes such that the intruder or its clones can be recognized when appearing elsewhere. However, secure, efficient and scalable sharing of intruder information remains a challenging and unsolved problem. To address this problem, we propose a three-tier framework, consisting of a verifiable intruder reporting (VIR) scheme, a quorum-based caching (QBC) scheme for efficiently propagating intruder reports to the whole network, and a collaborative Bloom Filter (CBF) scheme for handling intruder information locally. Extensive analysis and evaluations are also conducted to verify the efficiency and scalability of the proposed framework.
PRECISE N-GRAM PROBABILITIES FROM STOCHASTIC CONTEXT-FREE GRAMMARS

We present an algorithm for computing n-gram probabilities from stochastic context-free grammars, a procedure that can alleviate some of the standard problems associated with n-grams (estimation from sparse data, lack of linguistic structure, among others). The method operates via the computation of substring expectations, which in turn is accomplished by solving systems of linear equations derived from the grammar. The procedure is fully implemented and has proved viable and useful in practice.
Optimal Transport and Ricci Curvature for Metric- Measure Spaces

We survey work of Lott-Villani and Sturm on lower Ricci curvature bounds for metric-measure spaces. An intriguing question is whether one can extend notions of smooth Riemannian geome- try to general metric spaces. Besides the inherent interest, such extensions sometimes allow one to prove results about smooth Riemannian manifolds, using compactness theorems. There is a good notion of a metric space having "sectional curvature bounded below by K" or "sectional curvature bounded above by K", due to Alexandrov. We refer to the articles of Petrunin and Buyalo-Schroeder in this volume for further information on these two topics. In this article we address the issue of whether there is a good notion of a metric space having "Ricci curvature bounded below by K". A motivation for this question comes from Gromov's precompactness theorem (14, The- orem 5.3). Let M denote the set of compact metric spaces (modulo isometry) with the Gromov-Hausdorff topology. The precompactness theorem says that given N ∈ Z + , D < ∞ and K ∈ R, the subset of M consisting of closed Riemannian manifolds (M, g) with dim(M) = N, Ric ≥ Kg and diam ≤ D, is precompact. The limit points in M of this subset will be metric spaces of Hausdorff dimension at most N, but generally are not manifolds. However, one would like to say that in some generalized sense they do have Ricci curvature bounded below by K. Deep results about the structure of such limit points, which we call Ricci limits, were obtained by Cheeger and Colding (8, 9, 10). We refer to the article of Guofang Wei in this volume for further information. In the work of Cheeger and Colding, and in earlier work of Fukaya (13), it turned out to be useful to consider not just metric spaces, but rather metric spaces equipped with measures. Given a compact metric space (X, d), let P(X) denote the set of Borel probability measures on X. That is, ν ∈ P(X) means that ν is a nonnegative Borel measure on X with R X dν = 1. We put the weak-∗ topology on P(X), so limi→∞ νi = ν if and only if for all f ∈ C(X), we have limi→∞ R X f dνi = R X f dν. Then P(X) is compact. Definition 0.1. A compact metric measure space is a triple (X, d, ν) where (X, d) is a compact metric space and ν ∈ P(X). Definition 0.2. Given two compact metric spaces (X1, d1) and (X2, d2), an ǫ-Gromov- Hausdorff approximation from X1 to X2 is a (not necessarily continuous) map f : X1 → X2 so that
Practical Issues in Temporal Difference Learning

This paper examines whether temporal difference methods for training connectionist networks, such as Sutton's TD(λ) algorithm, can be successfully applied to complex real-world problems. A number of important practical issues are identified and discussed from a general theoretical perspective. These practical issues are then examined in the context of a case study in which TD(λ) is applied to learning the game of backgammon from the outcome of self-play. This is apparently the first application of this algorithm to a complex non-trivial task. It is found that, with zero knowledge built in, the network is able to learn from scratch to play the entire game at a fairly strong intermediate level of performance, which is clearly better than conventional commercial programs, and which in fact surpasses comparable networks trained on a massive human expert data set. This indicates that TD learning may work better in practice than one would expect based on current theory, and it suggests that further analysis of TD methods, as well as applications in other complex domains, may be worth investigating.
Limits of quantum speedup in photosynthetic light harvesting

It has been suggested that excitation transport in photosynthetic light-harvesting complexes features speedups analogous to those found in quantum algorithms. Here we compare the dynamics in these light-harvesting systems to the dynamics of quantum walks, in order to elucidate the limits of such quantum speedups. For the Fenna–Matthews–Olson complex of green sulfur bacteria, we show that while there is indeed speedup at short times, this is short lived (70 fs) despite longer-lived (ps) quantum coherence. Remarkably, this timescale is independent of the details of the decoherence model. More generally, we show that the distinguishing features of light-harvesting complexes not only limit the extent of quantum speedup but also reduce the rates of diffusive transport. These results suggest that quantum coherent effects in biological systems are optimized for efficiency or robustness rather than the more elusive goal of quantum speedup.
Ward's identity and the suppression of spin fluctuation superconductivity

Of crucial importance in superconductors is the vanishing of certain coherence factors, such as pkq = ukuk+q - vkvk+q for bare fermion energies {epsilon}k = {epsilon}k+q. This result leads to the abrupt drop of the acoustic attenuation rate below T{sub c} in conventional superconductors. Similarly the interference of {phi}k and {phi}k+Q for the statically distorted normal crystal leads to gkQ {yields} O, corresponding to a deformation potential theorem for the zone boundary phonon.
Limited-Rate Channel State Feedback for Multicarrier Block Fading Channels

The capacity of a fading channel can be substantially increased by feeding back channel state information from the receiver to the transmitter. If the feedback rate is limited, what state information to feed back and how to encode it are important questions. This paper studies power loading in a multicarrier system using no more than one bit of feedback per subchannel. The subchannels can be correlated and full channel state information is assumed at the receiver. First, a simple model with N parallel two-state (good/bad) memoryless subchannels is considered, where the channel state feedback is used to select a fixed number of subchannels to activate. The optimal feedback scheme is the solution to a vector quantization problem, and the associated performance for large N is characterized using a rate distortion function. As N increases, the loss in forward rate from the asymptotic (rate-distortion) value is shown to decrease as (logN)/N and √{(logN)/N} with optimal variable- and fixed-length feedback codes, respectively. These results are subsequently extended to parallel Rayleigh block fading subchannels, where the feedback designates a set of subchannels to be activated with equal power. Rate-distortion feedback codes are proposed for designating subsets of (good) subchannels with signal-to-noise ratios (SNRs) that exceed a threshold. The associated performance is compared with that of a simpler lossless source coding scheme, which designates groups of good subchannels, where both the group size and threshold are optimized. The rate-distortion codes can provide a significant increase in forward rate at low SNRs.
Democratic Values and Support for Militancy: Evidence From a National Survey of Pakistan

A long-standing research tradition on political culture argues that greater support for core liberal values leads to a rejection of destructive political activities and reduced support for violent ...
Diagnosis of Disorders of Iron Metabolism in Dogs and Cats

Most total body iron is found within heme, predominantly as hemoglobin of erythroidcells and myoglobin of muscle with lesser amounts within enzymatic hemoproteins. Asignificant amount of total body iron can also be in storage. Within cells, the mostimportant iron storage protein is ferritin. Much of stored iron is present within
A higher-order on-surface radiation condition derived from an analytic representation of a Dirichlet-to-Neumann map

On-surface radiation conditions are useful for obtaining approximate solutions to scattering problems involving compact obstacles. An analytic representation of the Dirichlet-to-Neumann map for a circle is derived and used to construct a higher-order on-surface radiation condition for a generally convex perfectly conducting body in two dimensions. This approach is based on a Hankel function in which a tangential operator appears in the index. In the high-frequency limit, this analytic representation approaches the square root of a differential operator which commonly arises in the application of parabolic equation techniques to propagation problems. Treating the scattered field propagation angle relative to the surface normal and the surface curvature as independent parameters, the representation is fit to a rational function to provide an accurate and efficient on-surface radiation condition that is tested for various examples.
Localized construction of bounded degree and planar spanner for wireless ad hoc networks

We propose a novel localized algorithm that constructs a bounded degree and planar spanner for wireless ad hoc networks modeled by unit disk graph (UDG). Every node only has to know its 2-hop neighbors to find the edges in this new structure. Our method applies the Yao structure on the local Delaunay graph [1] in an ordering that are computed locally. This new structure has the following attractive properties: (1) it is a planar graph; (2) its node degree is bounded from above by a positive constant 19 + ⌈2π/α⌉ (3) it is a t-spanner (given any two nodes u and v, there is a path connecting them in the structure such that its length is no more than t ≤ max {π/2, π sin α/2 + 1}. Cdel times of the shortest path in the unit disk graph); (4) it can be constructed locally and is easy to maintain when the nodes move around; (5) moreover, we show that the total communication cost is O(n log n) bits, where n is the number of wireless nodes, and the computation cost of each node is at most O(d log d), where d is its 2-hop neighbors in the original unit disk graph. Here Cdel is the spanning ratio of the Delaunay triangulation, which is at most 4√3/9 π. And the adjustable parameter α satisfies 0 < α ≤ π/3.
Anisotropic superconductivity in PrOs4Sb12

Recently two anisotropic superconducting gap functions have been observed in the skutterudite PrOs4Sb12. These order parameters are spin-triplet. There are at least 2 distinct phases in a magnetic field, bearing some resemblance to superfluid 3He. Here we present an analysis of the thermodynamic properties in these two superconducting states within the weak-coupling BCS theory.
Dynamic process management in an MPI setting

We describe an architecture for the runtime environment for parallel applications as prelude to describing how parallel applications might interface to their environment in a portable way. We propose extensions to the Message-Passing Interface (MPI) Standard that provide for dynamic process management, including spawning of new processes by a running application and connection to existing processes to support client/server applications. Such extensions are needed if more of the runtime environment for parallel programs is to be accessible to MPI programs or to be themselves written using MPI. The extensions proposed here are motivated by real applications and fit cleanly with existing concepts of MPI. No changes to the existing MPI Standard are proposed, thus all present MPI programs will run unchanged.
On convexification of polygons by pops

Given a polygon P in the plane, a pop operation is the reflection of a vertex with respect to the line through its adjacent vertices. We define a family of alternating polygons, and show that any polygon from this family cannot be convexified by pop operations. This family contains simple as well as non-simple (i.e., self-intersecting) polygons, as desired. We thereby answer in the negative an open problem posed by Demaine and O'Rourke (2007) [9, Open Problem 5.3].
A remark on bargaining and non-expected utility

Abstract We show that a bargaining game of alternating offers with exogenous risk of breakdown and played by dynamically consistent non-expected utility maximizers is formally equivalent to Rubinstein’s [Econometrica 50 (1982) 97] game with time preference. Within this game, the behavior of dynamically consistent players is indistinguishable from the behavior of expected utility maximizers.
Eigenvalue spectra and bounds for certain classes of dynamic systems having tree bond graphs

For a class of linear, time-invariant dynamic systems, information about the eigenvalues of the system can be obtained directly from a graphical model of the system, namely the bond graph model. In contrast to the standard approach, which starts from the state matrix of the system, we use a canonical form of the bond graph, namely the gyrobondgraph, to estimate bounds on the eigenvalues of the associated system. For some special cases, the entire spectrum of the system can be obtained by comparing the graph structure to existing graphs with known spectra. For more general cases, bounds are obtained on the largest real and imaginary parts of the eigenvalues as functions of the system's gyrobondgraph topology and its parameters. For some classes of systems, we present a simple graph-based recurrence formula for deriving the characteristic polynomial of a system from a simplified form of its gyrobondgraph. These results, when suitably automated, can reduce the time required to estimate the system performance.
The Benefits of Frequent Positive Affect: Does Happiness Lead to Success?

Numerous studies show that happy individuals are successful across multiple life domains, including marriage, friendship, income, work performance, and health. The authors suggest a conceptual model to account for these findings, arguing that the happiness-success link exists not only because success makes people happy, but also because positive affect engenders success. Three classes of evidence--crosssectional, longitudinal, and experimental--are documented to test their model. Relevant studies are described and their effect sizes combined meta-analytically. The results reveal that happiness is associated with and precedes numerous successful outcomes, as well as behaviors paralleling success. Furthermore, the evidence suggests that positive affect--the hallmark of well-being--may be the cause of many of the desirable characteristics, resources, and successes correlated with happiness. Limitations, empirical issues, and important future research questions are discussed.
Midwest cousins of Barnes-Wall lattices

Abstract Given a rational lattice and suitable set of linear transformations, we construct a cousin lattice. Sufficient conditions are given for integrality, evenness and unimodularity. When the input is a Barnes–Wall lattice, we get multi-parameter series of cousins. There is a subseries consisting of unimodular lattices which have ranks 2 d − 1 ± 2 d − k − 1 , for odd integers d ⩾ 3 and integers k = 1 , 2 , … , d − 1 2 . Their minimum norms are moderately high: 2 ⌊ d 2 ⌋ − 1 .
Ultra-high accuracy optical testing: creating diffraction-limited short-wavelength optical systems

Since 1993, research in the fabrication of extreme ultraviolet (EUV) optical imaging systems, conducted at Lawrence Berkeley National Laboratory (LBNL) and Lawrence Livermore National Laboratory (LLNL), has produced the highest resolution optical systems ever made. We have pioneered the development of ultra-high-accuracy optical testing and alignment methods, working at extreme ultraviolet wavelengths, and pushing wavefront-measuring interferometry into the 2–20-nm wavelength range (60–600 eV). These coherent measurement techniques, including lateral shearing interferometry and phase-shifting point-diffraction interferometry (PS/PDI) have achieved RMS wavefront measurement accuracies of 0.5–1-A and better for primary aberration terms, enabling the creation of diffraction-limited EUV optics. The measurement accuracy is established using careful null-testing procedures, and has been verified repeatedly through high-resolution imaging. We believe these methods are broadly applicable to the advancement of short-wavelength optical systems including space telescopes, microscope objectives, projection lenses, synchrotron beamline optics, diffractive and holographic optics, and more. Measurements have been performed on a tunable undulator beamline at LBNL’s Advanced Light Source (ALS), optimized for high coherent flux; although many of these techniques should be adaptable to alternative ultraviolet, EUV, and soft x-ray light sources. To date, we have measured nine prototype all-reflective EUV optical systems with NA values between 0.08 and 0.30 (ƒ/6.25 to ƒ/1.67). These projection-imaging lenses were created for the semiconductor industry’s advanced research in EUV photolithography, a technology slated for introduction in 2009–13. This paper reviews the methods used and our program’s accomplishments to date.
MARKET STRUCTURE AND CONSUMER VALUATION IN THE RBST-FREE AND ORGANIC MILK MARKETS

This study uses revealed preferences of consumers to study the consumer valuations of rBST-free and organic milk. The study specifies and estimates a quadratic AIDS model for different milk types using US supermarket scanner data. The introduction of rBSTfree and organic milk is used to estimate both competitive and variety effects as measures of consumer valuations. Results show significant consumer valuations for organic milk and to a lesser extent rBST-free milk.
Asymptotic Symmetries and Electromagnetic Memory

Recent investigations into asymptotic symmetries of gauge theory and gravity have illuminated connections between gauge field zero-mode sectors, the corresponding soft factors, and their classically observable counterparts — so called “memories”. Namely, low frequency emissions in momentum space correspond to long time integrations of the corre-sponding radiation in position space. Memory effect observables constructed in this manner are non-vanishing in typical scattering processes, which has implications for the asymptotic symmetry group. Here we complete this triad for the case of large U(1) gauge symmetries at null infinity. In particular, we show that the previously studied electromagnetic memory effect, whereby the passage of electromagnetic radiation produces a net velocity kick for test charges in a distant detector, is the position space observable corresponding to th Weinberg soft photon pole in momentum space scattering amplitudes.
Future of bone pathology, bone grafting, and osseointegration in oral and maxillofacial surgery: how applying optical advancements can help both fields

In recent years, advances in technology are propelling the field of oral and maxillofacial surgery into new realms. With a relatively thin alveolar mucosa overlying the underlying bone, significant diagnostic and therapeutic advantages are present; however, there remains an enormous gap between advancements in physics, in particular optics, and oral and maxillofacial surgery. Improvements in diagnosis, classification, and treatment of the various bone pathologies are still being sought after as advancements in technology continue to progress. Combining the clinical, histological, and pathological characteristics with these advancements, patients with debilitating pathologies may have more promising treatment options and prognosis. Defects in the facial bones, particularly in the jaws, may be due to a number of reasons: pathology, trauma, infections, congenital deformities, or simply due to atrophy. Bone grafting is commonly employed to correct such defects, and allows new bone formation through tissue regeneration. Growing use of dental implants has focused attention on osseointegration and its process. Osseointegration refers to the actual process of the direct contact between bone and implant, without an intervening soft tissue layer. The theories proposed regarding this process are many, yet a clear, unified stance on the actual process and its mechanisms has not emerged. Further investigation using optical probes could provide that unifying answer. The primary goal of this manuscript is to introduce pioneers in the field of optics to the field of oral and maxillofacial surgery. With a brief introduction into the procedures and techniques, we are hopeful to bridge the ever-widening gap between the clinical science and the basic sciences.
The Oxidation of Aldehydes to Methyl Esters using Trichloroisocyanuric Acid

Abstract Aldehydes are readily oxidized to methyl esters by a solution of methanol, pyridine, and trichloroisocyanuric acid in acetonitrile, acetone, or methylene chloride.
Discovery of tantalum, rhenium, osmium, and iridium isotopes

Currently, thirty-eight tantalum, thirty-eight rhenium, thirty-nine osmium, and thirty-eight iridium isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.
A Semianalytical Model for the Observational Properties of the Dominant Carbon Species at Different Metallicities

We present a simple, semianalytical approach to compute the line emission of C+, C0, and CO in photodissociation regions of varying metallicity that depends on very few parameters and naturally incorporates the clumpiness of the interstellar medium into the calculations. We use it to study the dependence of the I[C ii]/ICO and I[C i]/ICO line ratios on the metallicity. We show how to modify it to include the effects of density and radiation field, and we have compared it with observational data. We find that the model explains the observed trend of enhanced [C II]/CO line ratio with decreasing metallicity as the natural result of the augmented fraction of photodissociated gas in a clump. We show that enhanced [C II]/CO ratios can be produced by lowering the upper limit of the clump size distribution, as may happen in 30 Doradus. We also find that the available data favor a [C I]/CO intensity ratio essentially independent of metallicity, albeit the paucity of observations does not exclude other possibilities. This is difficult to understand if most of the C0 is produced by UV photons as is the case with C+. Finally, we study the prediction of the model for the trend of the XCO factor with metallicity. Comparison with previous observational studies yields good agreement.
The Quality of Managers in Centralized versus Decentralized Organizations

A central task of the leadership of any organization is the choice of its successors and subordinates. Corporate presidents spend a significant part of their time selecting upper management. Tenured faculty sometimes spends months deciding whether particular individuals should be admitted into their ranks. The effort and contentiousness which often go into this process suggests that it has important consequences for the organization. It is recognized that there are large differences in individuals' abilities and that the abilities of those in leadership inevitably affect the performance and survival of the organization. Our objective here is to examine how the centralization or decentralization of decision-making authority affects the quality of the managers who are actually selected. This question is naturally dynamic because the quality of current managers is not only influenced by that of past managers, but it, in turn, affects the quality of future managers. We consider stylized economies consisting of an arbitrary number of hierarchies (organizations) of different sizes. The size of a hierarchy is the number of managers within the hierarchy, one of whom is the hierarch (the boss) and others are subordinates. The current hierarch appoints his own successor and those of his subordinates, but has no influence on any other hierarchy. (This assumption exaggerates somewhat the typical asymmetry of authority between the hierarch and the subordinates.) Our definition of a "more" or "less" centralized economy is intuitive: an economy is more centralized if it has a larger proportion of the total number of managers in larger hierarchies. Our main result is that there is a greater variability (over time) in the steady-state quality of managers in a more centralized economy. This is because highly capable decision-makers have greater beneficial effects on the managerial choices in a more centralized economy. By the same token, highly incapable managers placed in the same positions have greater deleterious effects.
Projective embeddings of projective schemes blown up at subschemes

Suppose X is a nonsingular projective scheme, Z a nonsingular closed subscheme of X. Let ˜X be the blowup of X centered at Z, E0 the pull-back of a general hyperplane in X, and E the exceptional divisor. In this paper, we study projective embeddings of ˜X given by divisors . When X satisfies a necessary condition, we give explicit values of d and δ such that for all e>0 and embeds ˜X as a projectively normal and arithmetically Cohen-Macaulay scheme. We also give a uniform bound for the regularities of the ideal sheaves of these embeddings, and study their asymptotic behaviour as t gets large compared to e. When X is a surface and Z is a 0-dimensional subscheme, we further show that these embeddings possess property Np for all t⋙e>0.
Computing Puiseux series for algebraic surfaces

In this paper we outline an algorithmic approach to compute Puiseux series expansions for algebraic sets. The series expansions originate at the intersection of the algebraic set with as many coordinate planes as the dimension of the algebraic set. Our approach starts with a polyhedral method to compute cones of normal vectors to the Newton polytopes of the given polynomial system that defines the algebraic set. If as many vectors in the cone as the dimension of the algebraic set define an initial form system that has isolated solutions, then those vectors are potential tropisms for the initial term of the Puiseux series expansion. Our preliminary methods produce exact representations for solution sets of the cyclic n-roots problem, for n = m2, corresponding to a result of Backelin.
Neutrinos in supernovae

Abstract The role of neutrinos in Type II supernovae is discussed. An overall view of the neutrino luminosity as expected theoretically is presented. The different weak interactions involved are assessed from the standpoint of how they exchange energy, momentum, and lepton number. Particular attention is paid to entropy generation and the path to thermal and chemical equilibration, and to the phenomenon of trapping. Various methods used to calculate the neutrino flows are considered. These include trapping and leakage schemes, distribution-averaged transfer, and multi-energy group methods. The information obtained from the neutrinos caught from Supernova 1987a is briefly evaluated.
Lies, Defection, and the Pattern of International Cooperation

This article characterizes how incentives to lie affect international cooperation and the design of cooperation agreements. I study the optimal structure of cooperation agreements in an environment where the costs of cooperation fluctuate over time. Cooperation is complicated by the fact that the costs of cooperation are private information and participants can benefit from lying about them. When the extent of asymmetries of information between the cooperating governments can be measured in terms of the transparency of the political process, democracies face greater contracting opportunities than authoritarian regimes. However, this article shows that even under asymmetries of information, a limited extent of cooperation can be achieved when the design of cooperation agreements recognizes incentives to lie.
The Young Cluster in IC?1274

IC 1274 is a faintly luminous nebula lying on the near surface of the Lynds 227 (L227) molecular cloud. Its cavity-like morphology is reminiscent of a blistered star-forming region. Four luminous, early-type (B0-B5) stars are located within a spherical volume {approx}5' in diameter that appears to be clear of heavy obscuration. Approximately centered in the cleared region is the B0 V star HD 166033, which is thought to be largely responsible for the cavity's excavation. Over 80 H{alpha} emission sources brighter than V {approx} 21 have been identified in the region. More than half of these are concentrated in IC 1274 and are presumably members of a faint T Tauri star population. Chandra Advanced CCD Imaging Spectrometer imaging of a nearby suspected pulsar and time-variable {gamma}-ray source (GeV J1809-2327) detected 21 X-ray sources in the cluster vicinity, some of which are coincident with the early-type stars and H{alpha} emitters in IC 1274. Deep (V {approx} 22) optical BVRI photometry has been obtained for the cluster region. A distance of 1.82 {+-} 0.3 kpc and a mean extinction of A{sub V} {approx} 1.21 {+-} 0.2 mag follow from photometry of the early-type stars. Using pre-main-sequence evolutionary models, we derive a medianmore » age for the H{alpha} emitters and X-ray sources of {approx}1 Myr; however, a significant dispersion is present. Our interpretation of the structure of IC 1274 and the spatial distribution of H{alpha} emitters is that the early-type stars formed recently and are in the process of ionizing and dispersing the molecular gas on the near surface of L227. The displaced material was driven against what remains of the molecular cloud to the east, enabling the formation of the substantial number of T Tauri stars found there. A dispersed population of H{alpha} emitters is also found along the periphery of L227, IC 1275, and IC 4684. These sources, if pre-main-sequence stars, appear to have formed in relative isolation compared to the dense cluster environment of IC 1274 or, alternatively, may be older and have drifted further from their formation sites. We identify a V {approx} 21.5 star very near the position of X-ray source 5, the assumed {gamma}-ray source and young pulsar candidate. However, the lack of distinctive characteristics for this source, coupled with the density of faint stars in this region, suggest that this may be a random superposition.« less
Clustering high dimensional massive scientific datasets

Many scientific applications can benefit from an efficient clustering algorithm of massively large high dimensional datasets. However most of the developed algorithms are impractical to use when the amount of data is very large. Given N objects each defined by an M-dimensional feature vector any clustering technique for handling very large datasets in high dimensional space should run in time O(N) at best, and O(N log N) in the worst case, using no more than O(NM) storage, for it to be practical. A parallelized version of the same algorithm should achieve a linear speed-up in processing time with increasing number of processors. We introduce a hybrid algorithm called HyCeltyc, as an approach for clustering massively large high dimensional datasets. HyCeltyc, which stands for Hybrid Cell Density Clustering method combines a cell-density based algorithm with a hierarchical agglomerative method to identify clusters in linear time. The main steps of the algorithm involve sampling, dimensionality reduction and selection of significant features on which to cluster the data.
Assessment of cognitive and psychological functions in patients with multiple sclerosis: considerations for databasing

Test batteries for use in studying cognition and depression in patients are briefly but critically reviewed. Suggestions for a new battery that contains tests that are related to rehabilitation and work status are proposed.
Restricting Grazing on Federal Lands in the West to Protect Threatened and Endangered Species: Ranch and Livestock Sector Impacts

Ranch and livestock sector impacts are estimated for a 10% reduction in grazing on federal lands in the West to protect threatened and endangered species. Two sets of species are considered. One set targets species listed due to grazing and the other targets species whose recovery plans include restrictions on grazing. Using the former set and assuming no substitution between alternative sources of forage, the grazing restriction reduces annual ranch and livestock sector incomes by $54.4 and $83.7 million, respectively. For the latter set, the decreases in ranch and livestock sector incomes are $47.7 and $73.4 million, respectively. F or decades, access to federal lands for the purpose of grazing livestock has been governed by a system of fees and leases. The principal agencies involved are the Forest Service (FS) and the Bureau of Land Management (BLM). In 1993, these agencies administered grazing leases covering, respectively, 97 million and 167 million acres of federal land (U.S. Department of the Interior; U.S. Department of Agriculture, 1994).1 On many of these lands, grazing has been linked to the degradation of wildlife resources, particularly with respect to riparian areas, semiarid habitats, and the jeopardy facing many threatened and endangered (TE Fleischner; McKenzie and Riley; BioData Inc.). As a result, much of the current debate regarding the future use of public lands in the West centers around ranchers who want to ensure continued access for livestock and conservation groups who want these lands to emphasize production of goods and services associated with wildlife and natural ecosystems.2 One means by which conservation groups have tried to reduce grazing on federal lands has been to pursue legal actions charging ranchers and government
The nonlinear electromigration of analytes into confined spaces

We consider the problem of electromigration of a sample ion (analyte) within a uniform background electrolyte when the confining channel undergoes a sudden contraction. One example of such a situation arises in microfluidics in the electrokinetic injection of the analyte into a micro-capillary from a reservoir of much larger size. Here, the sample concentration propagates as a wave driven by the electric field. The dynamics is governed by the Nerst–Planck–Poisson system of equations for ionic transport. A reduced one-dimensional nonlinear equation, describing the evolution of the sample concentration, is derived. We integrate this equation numerically to obtain the evolution of the wave shape and determine how the injected mass depends on the sample concentration in the reservoir. It is shown that due to the nonlinear coupling of the ionic concentrations and the electric field, the concentration of the injected sample could be substantially less than the concentration of the sample in the reservoir.
Bounds on prices of contingent claims in an intertemporal economy with proportional transaction costs and general preferences

Analytic bounds on the reservation write price of European-style con- tingent claims are derived in the presence of proportional transaction costs in a model which allows for intermediate trading. The option prices are obtained via a utility maximization approach by comparing the maximized utilities with and without the contingent claim. The mathematical tools come mainly from the theories of singular stochastic control and viscosity solutions of nonlinear partial differential equations.
A retrospective on the journal of computer-aided materials design (JCAD), 1993–2007

In 1993 The Journal of Computer-Aided Materials Design (JCAD) was launched by a small publishing company in the Netherlands, ESCOM. The Publisher, Dr. Elizabeth Schram, had invited four scientists with common interests in computer simulations of materials to serve as editors. The motivation then was that atomistic and molecular simulations were being recognized as emerging computational tools for materials research, so it seemed reasonable to anticipate that they could be integrated into the process of design. “Since in both analysis and design one can intrinsically exploit the remarkable (and ever-increasing) capabilities of computer hardware and software technology, the intersection of computation, in the broad sense, and materials design, with its holistic nature, naturally delineates a range of issues which need to be addressed at the present time.” As for the name of the Journal, the decision was at least partially influenced by the success of another ESCOM journal, the Journal of Computer-Aided Molecular Design (JCAMD). The four editors were Anthony K. Cheetham (University of California Santa Barbara) Ulrich W. Suter (ETH Zurich), Erich Wimmer (then with Biosym in Paris), and me. After about 3years it was decided that it would be more efficient if one person would act as the Principal Editor to oversee all the operational affairs, with the other three assisting primarily in soliciting manuscripts. The understanding was that this arrangement would rotate about every three years. History shows that I was chosen to go first in this capacity, and subsequent handoffs never occurred. How did things work out? If I were asked, my answer would be the journey was up and down. JCADwitnessed the period when multiscale materials modeling and simulation began to flourish from modest topical workshops to sizable international conferences. One of the most satisfying experiences for me is that the Journal has played a sustained role in building this community. In the late 1990s the DOE launched the initiative ASCI (Accelerated Strategic Computing Initiative) as part of its stockpile stewardship program, which provided major impetus for
Counting faces of randomly-projected polytopes when the projection radically lowers dimension

1.1. Three surprises of high dimensions. This paper develops asymptotic methods to count faces of random high-dimensional polytopes; a seemingly dry and unpromising pursuit. Yet our conclusions have surprising implications - in statistics, probability, information theory, and signal processing - with potential impacts in practical subjects like medical imaging and digital communications. Before involving the reader in our lengthy analysis of high-dimensional face counting, we describe three implications of our results. 1.1.1. Convex Hulls of Gaussian Point Clouds. Consider a random point cloud of n points xi, i = 1, . . . , n, sampled independently and identically from a Gaussian distribution in R d with nonsingular covariance. This is a standard model of multivariate data; its properties are increasingly important in a wide range of applications. At the same time, it is an attractive and in some sense timeless object for theoretical study. Properties of the convex hull of the random point cloud X = {xi} have attracted interest for several decades, increasingly so in recent years; there is a nowvoluminous literature on the subject. The results could be significant for understanding outlier detection, or classification problems in machine learning.
Using Count Data Models in Travel Cost Analysis with Aggregate Data

Estimators of recreational demand models frequently use continuous functional forms, such as ordinary least squares (OLS) on log transformed variables (e.g., Ziemer, Musser, and Hill). However, the nature of trip demand introduces complicating factors. First, trips occur in nonnegative quantities. Failure to control for this censoring will lead to biased estimation. Second, because trips are available only in integer quantities, the usual demand models, which correlate marginal quantity with marginal price, may be inapplicable. In light of these factors, a natural alternative is to use statistical models that explicitly recognize the "count" nature of trip demand. Several recent papers (e.g., Shaw, Smith, Grogger and Carson, Creel and Loomis) have applied count models to the travel cost model. These works largely have focused on truncated data sets based on choice-based samples. In this study the focus is on the older problem where zero-demanders are included. In particular, the application of several robust estimators of count models to aggregated data will be considered. The Poisson distribution forms the foundation for the count models examined in this study. Although the Poisson is a convenient distribution to work with, it imposes some stringent constraints on the demand distribution. In particular, the Poisson distribution assumes the variance of trip demand is equal to the expected value of trip demand. To loosen these constraints, a generalization of the Poisson, the negative binomial, is discussed. Robust estimation procedures, that permit further loosening of a priori assumptions are then reviewed. Permit data from the Boundary Waters Canoe Area are used to examine the effects of these count models on consumer surplus estimates and on coefficient variability.
Structural variation analysis with strobe reads

Motivation: Structural variation including deletions, duplications and rearrangements of DNA sequence are an important contributor to genome variation in many organisms. In human, many structural variants are found in complex and highly repetitive regions of the genome making their identification difficult. A new sequencing technology called strobe sequencing generates strobe reads containing multiple subreads from a single contiguous fragment of DNA. Strobe reads thus generalize the concept of paired reads, or mate pairs, that have been routinely used for structural variant detection. Strobe sequencing holds promise for unraveling complex variants that have been difficult to characterize with current sequencing technologies. Results: We introduce an algorithm for identification of structural variants using strobe sequencing data. We consider strobe reads from a test genome that have multiple possible alignments to a reference genome due to sequencing errors and/or repetitive sequences in the reference. We formulate the combinatorial optimization problem of finding the minimum number of structural variants in the test genome that are consistent with these alignments. We solve this problem using an integer linear program. Using simulated strobe sequencing data, we show that our algorithm has better sensitivity and specificity than paired read approaches for structural variation identification. Contact: braphael@brown.edu
Chronic Illness and Health Insurance-Related Job Lock

Job duration patterns are examined for evidence of health insurance-related job lock among chronically ill workers or workers whose family member is chronically ill. Using Cox proportional hazard models to indicate the effect of health insurance and health status on workers' job duration we allow for more general insurance effects than that shown in the existing literature. Data for workers in Indiana predating the Health Insurance Portability and Accountability Act (HIPAA) are used to examine the potential effect of HIPAA on job mobility. Among the workers in this sample who relied on their employer for coverage, chronic illness reduced job mobility by about 40 percent as compared with otherwise similar workers who did not rely on their employer for coverage. Results reported here identify previously under-appreciated job lock among chronically ill workers and workers whose family member is chronically ill, clarify how one best researches job lock, and indicate the potential effect of policies aimed at alleviating job lock and promoting inter-employer worker mobility. © 2001 by the Association for Public Policy Analysis and Management.
Small Zeros of Quadratic Forms with Linear Conditions

Abstract Given a quadratic form and M linear forms in N +1 variables with coefficients in a number field K , suppose that there exists a point in K N +1 at which the quadratic form vanishes and all the linear forms do not. Then we show that there exists a point like this of relatively small height. This generalizes a result of D.W. Masser.
Grid Marketing and Beef Carcass Quality: A Discussion of Issues and Trends

Beef industry data suggest that improvements in carcass yield and quality grades have stagnated recently. Empirical analysis, based on USDA market reports, indicates that the share of steer slaughter volume marketed on a grid is less than industry estimates and the growth in market share has stagnated. Trend analysis of market share suggests that grid pricing has become an important marketing channel, but has not become the dominant marketing channel. The lack of industry progress toward achieving the carcass quality goals suggests that grid pricing has not captured the level of market share needed to realize the goals envisioned for it as a value based marketing system.