cssi/SciSciGPT-SciSciNet huggingface dataset:
Outer Jet X-Ray and Radio Emission in R Aquarii: 1999.8 to 2004.0

Chandra and VLA observations of the symbiotic star R Aqr in 2004 reveal significant changes over the 3-4 year interval between these observations and previous observations taken in with the VLA in 1999 and with Chandra in 2000. This paper reports on the evolution of the outer thermal X-ray lobe jets and radio jets. The emission from the outer X-ray lobe jets lies farther away from the central binary than the outer radio jets and comes from material interpreted as being shock-heated to 106 K, a likely result of collision between high-speed material ejected from the central binary and regions of enhanced gas density. Between 2000 and 2004, the northeast (NE) outer X-ray lobe jet moved out, away from the central binary, with an apparent projected motion of 580 km s-1. The southwest (SW) outer X-ray lobe jet almost disappeared between 2000 and 2004, presumably due to adiabatic expansion and cooling. The NE radio-bright spot also moved away from the central binary between 2000 and 2004, but with a smaller apparent velocity than the NE X-ray-bright spot. The SW outer lobe jet was not detected in the radio in either 1999 or 2004. The density and mass of the X-ray-emitting material is estimated. Cooling times, shock speeds, pressure, and confinement are discussed.
Sortable Elements for Quivers with Cycles

Each Coxeter element $c$ of a Coxeter group $W$ defines a subset of $W$ called the $c$-sortable elements. The choice of a Coxeter element of $W$ is equivalent to the choice of an acyclic orientation of the Coxeter diagram of $W$. In this paper, we define a more general notion of $\Omega$-sortable elements, where $\Omega$ is an arbitrary orientation of the diagram, and show that the key properties of $c$-sortable elements carry over to the $\Omega$-sortable elements. The proofs of these properties rely on reduction to the acyclic case, but the reductions are nontrivial; in particular, the proofs rely on a subtle combinatorial property of the weak order, as it relates to orientations of the Coxeter diagram. The $c$-sortable elements are closely tied to the combinatorics of cluster algebras with an acyclic seed; the ultimate motivation behind this paper is to extend this connection beyond the acyclic case.
Developments in on-line, electron-beam emittance measurements using optical-transition radiation techniques

Abstract We have developed image analysis software to facilitate the analysis of optical-transition radiation (OTR) patterns generated by the electron beam from the Los Alamos free-electron laser facility. The software can be used for beam alignment, beam profile and angular divergence measurements, and the programs run on an IBM AT microcomputer. The programs and their use are described and some results shown.
ESSENCE AGAINST IDENTITY

: This paper traces how the concern with political transformation is central both to arguments for and against essentialism. But while pro-essential argumentation is concerned with identity, as a condition of change, anti-essentialist reasoning sees change as dependent on the historical mutability of identity. Using Freud, this paper attempts to reconcile these positions through focusing first, on identification rather than identity; and second, on an unorthodox concept of essence, stressing its energetic commonality between beings.
Well-Typed Islands Parse Faster

This paper addresses the problem of specifying and parsing the syntax of domain-specific languages DSLs in a modular, user-friendly way. We want to enable the design of composable DSLs that combine the natural syntax of external DSLs with the easy implementation of internal DSLs. The challenge in parsing these DSLs is that the composition of several languages is likely to contain ambiguities. We present the design of a system that uses a type-oriented variant of island parsing to efficiently parse the syntax of composable DSLs. In particular, we argue that the running time of type-oriented island parsing doesn't depend on the number of DSLs imported. We also show how to use our tool to implement DSLs on top of a host language such as Typed Racket.
Monomial and toric ideals associated to Ferrers graphs

Each partition A = (λ 1 , λ 2 ,..., An) determines a so-called Ferrers tableau or, equivalently, a Ferrers bipartite graph. Its edge ideal, dubbed a Ferrers ideal, is a squarefree monomial ideal that is generated by quadrics. We show that such an ideal has a 2-linear minimal free resolution; i.e. it defines a small subscheme. In fact, we prove that this property characterizes Ferrers graphs among bipartite graphs. Furthermore, using a method of Bayer and Sturmfels, we provide an explicit description of the maps in its minimal free resolution. This is obtained by associating a suitable polyhedral cell complex to the ideal/graph. Along the way, we also determine the irredundant primary decomposition of any Ferrers ideal. We conclude our analysis by studying several features of toric rings of Ferrers graphs. In particular we recover/establish formulae for the Hilbert series, the Castelnuovo-Mumford regularity, and the multiplicity of these rings. While most of the previous works in this highly investigated area of research involve path counting arguments, we offer here a new and self-contained approach based on results from Gorenstein liaison theory.
Automating metadata web service deployment for problem solving environments

XML-based metadata information services are a crucial core service needed by problem solving environments built over emerging service-based, globally scaled distributed systems, as envisioned by the Open Grid Services Architecture and the Semantic Web. Developing user interfaces and service bindings for manipulating instances of particular schemas is thus extremely important and needs to be made as simple as possible. In this paper we describe procedures for automating the creation of Web service environments that can be used to simplify the creation and deployment of schema-based metadata services.
The effect of experience on security analyst underreaction

Abstract We examine if analysts more fully incorporate prior earnings and returns information in their current quarter forecasts as their experience following a firm increases. We measure analyst firm-specific forecasting experience as the number of prior quarters for which the analyst has issued an earnings forecast for the firm. We find that analysts underreact to prior earnings information less as their experience increases, suggesting one reason why analysts become more accurate with experience.
Does it pay to be SMarT

The Save More Tomorrow™ (or SMarT) plan has proven effective in raising employee saving rates and appears to be popular among participants and the media. An important question has remained on the minds of economists despite this success: just how close does the prescriptive SMarT plan come to approximating the normative life-cycle/permanent-income consumption rule? That is, does it pay (in a lifetime utility sense) to participate in a SMarT plan? We attempt to provide some rigorous answers to this question by employing a quantitative-theoretic model to perform dynamic welfare analysis, and our results tend to support the SMarT plan as a decent first approximation to the life-cycle/permanent-income rule. We also consider the problem of an altruistic employer seeking to maximize the lifetime utility of employees by appropriately choosing the default SMarT parameters in the face of employee heterogeneity in saving rates and uncertainty about whether they will actually stick with the plan. The employer's problem is augmented to include employee heterogeneity concerning risk taking, and we also consider the possibility that SMarT saving may be met with increased borrowing.
Relating symbolic and cryptographic secrecy

We investigate the relation between symbolic and cryptographic secrecy properties for cryptographic protocols. Symbolic secrecy of payload messages or exchanged keys is arguably the most important notion of secrecy shown with automated proof tools. It means that an adversary restricted to symbolic operations on terms can never get the entire considered object into its knowledge set. Cryptographic secrecy essentially means computational indistinguishability between the real object and a random one, given the view of a much more general adversary. In spite of recent advances in linking symbolic and computational models of cryptography, no relation for secrecy under active attacks is known yet. For exchanged keys, we show that a certain strict symbolic secrecy definition over a specific Dolev-Yao-style cryptographic library implies cryptographic key secrecy for a real implementation of this cryptographic library. For payload messages, we present the first general cryptographic secrecy definition for a reactive scenario. The main challenge is to separate secrecy violations by the protocol under consideration from secrecy violations by the protocol users in a general way. For this definition we show a general secrecy preservation theorem under reactive simulatability, the cryptographic notion of secure implementation. This theorem is of independent cryptographic interest. We then show that symbolic secrecy implies cryptographic payload secrecy for the same cryptographic library as used in key secrecy. Our results thus enable existing formal proof techniques to establish cryptographically sound proofs of secrecy for payload messages and exchanged keys.
Reducing the Error Floor

We discuss how the loop calculus approach of [Chertkov, Chernyak '06], enhanced by the pseudo-codeword search algorithm of [Chertkov, Stepanov '06] and the facet-guessing idea from [Dimakis, Wainwright '06], improves decoding of graph based codes in the error-floor domain. The utility of the new, linear programming based, decoding is demonstrated via analysis and simulations of the model [155,64, 20] code.
Thermal performance limits of the QFP family

The quad flat package (QFP) finds wide use in current electronic systems, PCs, and workstations, housing a variety of devices. This study projects the thermal performance limits of the QFP family. The metrics chosen are the maximum power dissipated for constraints of junction temperature ( >
An Initial Evaluation of the Tera Multithreaded Architecture and Programming System Using the C3I Parallel Benchmark Suite

The Tera Multithreaded Architecture (MTA) is a radical new architecture intended to revolutionize high-performance computing in both the scientific and commercial marketplaces. Each processor supports 128 threads in hardware. Extremely fast thread switching is used to mask latency in a uniform-access memory system without caching. It is claimed that these hardware characteristics allow compilers to easily transform sequential programs into efficient multithreaded programs for the Tera MTA. In this paper, we attempt to provide an objective initial evaluation of the performance of the Tera multithreaded architecture and programming system for general-purpose applications. The basis of our investigation is two programs from the C3I Parallel Benchmark Suite (C3IPBS). Both these programs have previously been shown to have the potential for large-scale parallelization. We compare the performance of these programs on (i) a fast uniprocessor, (ii) two conventional shared-memory multiprocessors, and (iii) the first installed Tera MTA (at the San Diego Supercomputer Center). On these platforms, we compare the effectiveness of both automatic and manual parallelization.
Proof of the umbral moonshine conjecture

The Umbral Moonshine Conjectures assert that there are infinite-dimensional graded modules, for prescribed finite groups, whose McKay–Thompson series are certain distinguished mock modular forms. Gannon has proved this for the special case involving the largest sporadic simple Mathieu group. Here, we establish the existence of the umbral moonshine modules in the remaining 22 cases.
2-photon 3-D lithography

Summary form only given. Recent advances in the development of highly sensitive two-photon photoactive materials and their application in 3D lithographic microfabrication will be presented.
Radiance caching for participating media

In this article we present a novel radiance caching method for efficiently rendering participating media using Monte Carlo ray tracing. Our method handles all types of light scattering including anisotropic scattering, and it works in both homogeneous and heterogeneous media. A key contribution in the article is a technique for computing gradients of radiance evaluated in participating media. These gradients take the full path of the scattered light into account including the changing properties of the medium in the case of heterogeneous media. The gradients can be computed simultaneously with the inscattered radiance with negligible overhead. We compute gradients for single scattering from lights and surfaces and for multiple scattering, and we use a spherical harmonics representation in media with anisotropic scattering. Our second contribution is a new radiance caching scheme for participating media. This caching scheme uses the information in the radiance gradients to sparsely sample as well as interpolate radiance within the medium utilizing a novel, perceptually based error metric. Our method provides several orders of magnitude speedup compared to path tracing and produces higher quality results than volumetric photon mapping. Furthermore, it is view-driven and well suited for large scenes where methods such as photon mapping become costly.
Pulse Modulated Control Synthesis for a Flexible Spacecraft

The describing function method is employed for the nonlinear control analysis and design of a flexible spacecraft equipped with pulse modulated reaction jets. The method provides a means of characterizing the pulse modulator in terms of its gain and phase for structural mode limit cycle analysis. Although the describing function method is inherently inexact and is not widely used in practice, a new way of utilizing it for practical control design problems is presented. It is shown that the approximations inherent in the method can be accounted as a modeling uncertainty for the nonlinear control robustness analysis. The pulse modulated control system of the INTELSAT 5 spacecraft is used as an example to illustrate the concept and methodology developed in the gaper. The nonlinear stability margins predicted by the describing function analysis are verified from nonlinear simulations.
Sweeping an oval to a vanishing point

Given a convex region in the plane, and a sweep-line as a tool, what is the best way to reduce the region to a single point by a sequence of sweeps? The problem of sweeping points by orthogonal sweeps was first studied in [2]. Here we consider the following slanted variant of sweeping recently introduced in [1]: in a single sweep, the sweep-line is placed at a start position somewhere in the plane, then moved continuously according to a sweep vector v-> (not necessarily orthogonal to the sweep-line) to another parallel end position, and then lifted from the plane. The cost of a sequence of sweeps is the sum of the lengths of the sweep vectors. The optimal sweeping cost of a region is the infimum of the costs over all finite sweeping sequences for that region. An optimal sweeping sequence for a region is one with a minimum total cost, if it exists. Another parameter of interest is the number of sweeps. We show that there exist convex regions for which the optimal sweeping cost cannot be attained by two sweeps. This disproves a conjecture of Bousany, Karker, O'Rourke, and Sparaco stating that two sweeps (with vectors along the two adjacent sides of a minimum-perimeter enclosing parallelogram) always suffice [1]. Moreover, we conjecture that for some convex regions, no finite sweeping sequence is optimal. On the other hand, we show that both the 2-sweep algorithm based on the minimum-perimeter enclosing rectangle and the 2-sweep algorithm based on the minimum-perimeter enclosing parallelogram achieve a 4/@p~1.27 approximation of the optimal sweeping cost in this model.
Molecular and Mesoscale Mechanisms of Osteogenesis Imperfecta Disease

Collagen is a crucial structural protein material, formed through a hierarchical assembly of tropocollagen molecules, arranged in collagen fibrils that constitute the basis for larger-scale fibrils and fibers. Osteogenesis imperfecta is a genetic disorder in collagen characterized by mechanically weakened tendon, fragile bones, skeletal deformities and in severe cases prenatal death. Even though many studies have attempted to associate specific mutation types with phenotypic severity, the mechanisms by which a single point mutation influences the mechanical behavior of tissues at multiple length-scales remain unknown. In this study, we report a series of systematic molecular scale based bottom-up computational experiments focused on pure collagenous tissue, carried out using atomistic-level molecular dynamics (MD), adaptive Poison-Boltzmann solver (APBS) calculations, and a mesoscale molecular model of collagen fibrils.Copyright © 2010 by ASME
Toward the best constant factor for the Rademacher-Gaussian tail comparison

It is proved that the best constant factor in the Rademacher-Gaussian tail comparison is between two explicitly defined absolute constants c 1 and c 2 such that c 2 ≈ 1.01 c 1 . A discussion of relative merits of this result versus limit theorems is given.
Adjuvant chemotherapy for non-small cell lung cancer

In the late 1970s and early 1980s, the Lung Cancer Study Group conducted a series of adjuvant chemotherapy trials in patients with resected non-small cell lung cancer. Although some of these trials yielded modest survival benefit, the length of improved survival essentially equaled the time spent receiving chemotherapy. Consequently, few physicians routinely employ postoperative chemotherapy in spite of its theoretical appeal. Possible explanations for the failure of adjuvant chemotherapy to provide meaningful prolongation of survival in non-small cell lung cancer include lack of effective chemotherapy, incorrect chemotherapy regimen, inadequate dose intensity, and possibly inadequate trial design. Future postoperative adjuvant trials should focus on treating patients with resected early stage lesions (T1N1, T2N1, T2N0). What role, if any, newer antineoplastic agents will play in the postoperative setting remains to be determined. Neoadjuvant induction chemotherapy may well prove to be a superior treatment strategy and deserves further investigation.
Effect of antenna aircraft interaction on phased-array radar performance

Large ultralow sidelobe airborne array antennas are required for detection of low radar cross section targets against a background of complex clutter and jammer interference. One of the critical factors which limits the clutter and jammer suppression performance of adaptive phased-array radars is the impact of the aircraft in the near-field of an ultralow sidelobe antenna. A simulation featuring a cost-effective method of predicting performance is described, together with the modeling of the aircraft and airborne radar simulation. The performances attainable in the airborne environment for two possible antenna-aircraft platform configurations are compared using the Ohio State University geometrical theory of diffraction numerical code. >
A Decade of Debt

Public debts in the advanced economies have surged in recent years to levels that have not been recorded since the end of World War II. Through 2010 the average public debt/GDP ratio for all the advanced economies has surpassed the pre-World War II peaks reached during the World War I and subsequently during the Great Depression. Private debt levels particularly those of financial institutions and households are similarly in uncharted territory and represent (in varying degrees) potential contingent liability of the public sector in many countries including the US.
Antidiabetic, Chemical, and Physical Properties of Organic Vanadates as Presumed Transition-State Inhibitors for Phosphatases

Studies of antidiabetic vanadium compounds, specifically the organic vanadate esters, are reviewed with regard to their chemistry and biological properties. The compounds are described from the perspective of how the fundamental chemistry and properties of organic vanadate esters impact their effects as inhibitors for phosphatases based on the structural information obtained from vanadium-phosphatase complexes. Vanadium compounds have been reported to have antidiabetic properties for more than a century. The structures and properties of organic vanadate complexes are reviewed, and the potency of such vanadium coordination complexes as antidiabetic agents is described. Because such compounds form spontaneously in aqueous environments, the reactions with most components in any assay or cellular environment has potential to be important and should be considered. Generally, the active form of vanadium remains elusive, although studies have been reported of a number of promising vanadium compounds. The description of the antidiabetic properties of vanadium compounds is described here in the context of recent characterization of vanadate-phosphatase protein structures by data mining. Organic vanadate ester compounds are generally four coordinate or five coordinate with the former being substrate analogues and the latter being transition-state analogue inhibitors. These studies demonstrated a framework for characterization of five-coordinate trigonal bipyramidal vanadium inhibitors by comparison with the reported vanadium-protein phosphatase complexes. The binding of the vanadium to the phosphatases is either as a five-coordinate exploded transition-state analogue or as a high energy intermediate, respectively. Even if potency as an inhibitor requires trigonal bipyramidal geometry of the vanadium when bound to the protein, such geometry can be achieved upon binding from compounds with other geometries. Desirable properties of ligands are identified and analyzed. Ligand interactions, as reported in one peptidic substrate, are favorable so that complementarity between phosphatase and coordinating ligand to the vanadium can be established resulting in a dramatic enhancement of the inhibitory potency. These considerations point to a frameshift in ligand design for vanadium complexes as phosphatase inhibitors and are consistent with other small molecule having much lower affinities. Combined, these studies do suggest that if effective delivery of potentially active antidiabetic compound such a the organic vanadate peptidic substrate was possible the toxicity problems currently reported for the salts and some of the complexes may be alleviated and dramatic enhancement of antidiabetic vanadium compounds may result.
Differentiated congestion pricing of urban transportation networks with vehicle-tracking technologies ☆

This paper explores a new type of congestion pricing that differentiates users with respect to their travel characteristics or attributes, and charges them different amounts of toll accordingly. The scheme can reduce the financial burden of travelers or lead to more substantial reduction of congestion. Given that the scheme requires tracking vehicles, an incentive program is designed to mitigate travelers’ privacy concerns and entice them to voluntarily disclose their location information.
Nanonickel‐Catalyzed Suzuki–Miyaura Cross‐Couplings in Water

Nickel nanoparticles, formed in situ and used in combination with micellar catalysis, catalyze Suzuki-Miyaura cross-couplings in water under very mild reaction conditions.
Equilibrium Selection, Similarity Judgments and the "Nothing to Gain/Nothing to Lose" Effect

Rubinstein (1988, 2003) and Leland (1994, 1998, 2001, 2002) have shown that choices based on similarity judgments will account for the vast majority of observed violations of expected and discounted utility. In this paper, I show that such judgments also explain which equilibria will be selected in single-shot games with multiple equilibria, predict circumstances in which non-equilibria outcomes may predominate in such games, and predict circumstances in which specific pure strategy outcomes will predominate in games with no pure strategy equilibria.
Ideas, structure, state action and economic growth: Rethinking the Irish miracle

ABSTRACT This paper advances an argument about the need to take into account two components of state-industry relations if we are to fully understand economic development and policy trajectory, as well as industry-state co-evolution. The first component, the specific structure of the bureaucracy and state-industry relations, has been the focus of intense research. However, the second, the particular industrial economic ideology defining the correct role of the state in industry and industry in a state, is at least as important, if under-researched. In order to do empirically advance the argument the paper merges a cognitive-based constructivist argument with a neo-developmental state structuralist one, to present a new understanding of the role of the state in the Irish miracle that explains not only its success and failures but its internal dissonances, such as the continuous discrimination of the local, Irish-owned, industry in favor of foreign-owned MNCs. The paper illustrates how a particular industri...
PT symmetry as a necessary and sufficient condition for unitary time evolution.

While Hermiticity of a time-independent Hamiltonian leads to unitary time evolution, in and of itself, the requirement of Hermiticity is only sufficient for unitary time evolution. In this paper, w...
Constraints on Supersymmetric Flavour Models from b ---> s gamma

We consider the effects of departures from minimal flavour violations (MFV) in the context of CMSSM-like theories. Second and third generation off-diagonal elements in the Yukawa, sfermion, and trilinear mass matrices are taken to be non-zero at the GUT scale. These are run down together with MSSM parameters to the electroweak scale. We apply constraints from fermion masses and CKM matrix elements to limit the range of the new free parameters of the model. We determine the effect of the departure from MFV on the branching ratio of b→s γ. We find that only when the expansion parameter in the down-squark sector is relatively large there is a noticeable effect, which tends to relax the lower limit from b→s γ on the universal gaugino mass. We also find that the expansion parameter associated with the slepton sector needs to be smaller than the corresponding parameter in the down-squark sector in order to be compliant with the bound imposed by the branching ratio of τ→μγ.
A study of practical implementations of the Overlap-Dirac operator in four dimensions

Abstract We study three practical implementations of the overlap Dirac operator D 0 = 1 2 [1+γϵ( H w )] in four dimensions. Two implementations are based on different representations of ϵ( H w ) as a sum over poles. One of them is a polar decomposition and the other is an optimal fit to a ratio of polynomials. The third one is obtained by representing ϵ( H w ) using Gegenbauer polynomials and is referred to as the fractional inverse method. After presenting some spectral properties of the Hermitian operator H 0 = γ 5 D 0 , we study its spectrum in a smooth SU(2) instanton properties of the with the aim of comparing the three implementations of D 0 . We also present some results in SU(2) gauge field backgrounds generated at β = 2.5 on an 8 4 lattice. Chiral properties have been numerically verified.
Pattern regularity as a visual key

Abstract This paper gives a summary of our research on pattern regularity. Periodic structures are perceived by humans as regular in a wide range of viewing angles. This observation motivates the development of a regularity based feature vector whose affine invariance is justified theoretically and tested experimentally. The vector is derived from the interaction map of a pattern. Several alternative but closely related definitions of the interaction map are discussed. The maximal regularity, a component of the feature vector, is shown to be consistent with human judgement on regularity. This feature can be implemented as a run filter, allowing for regularity based image filtering. Three applications of the regularity approach are presented. First, it is used for affine-invariant texture classification. Then, detection of periodic structures in aerial images is demonstrated. Finally, the texture inspection problem is addressed and structural defects are found as locations of low regularity.
Cosmic Ray Scattering in Compressible Turbulence

We study the scattering of low-energy cosmic rays (CRs) in a turbulent, compressive magne- tohydrodynamic (MHD) fluid. We show that compressible MHD modes - fast or slow waves with wavelengths smaller than CR mean free paths induce cyclotron instability in CRs. The in- stability feeds the new small-scale Alfvenic wave component with wavevectors mostly along magnetic field, which is not a part of the MHD turbulence cascade. This new component gives feedback on the instability through decreasing the CR mean free path. We show that the ambient turbulence fully suppresses the instability at large scales, while wave steepening constrains the amplitude of the waves at small scales. We provide the energy spectrum of the plane-parallel Alfvenic component and calculate mean free paths of CRs as a function of their energy. We find that for the typical parameters of turbulence in the interstellar medium and in the intercluster medium the new Alfvenic component provides the scattering of the low-energy CRs that exceeds the direct resonance scattering by MHD modes. This solves the problem of insufficient scattering of low-energy CRs in the turbulent interstellar or intracluster medium that was reported in the literature.
Microwave harmonic generation in a plasma capacitor

Microwave harmonic generation in a plasma capacitor is investigated both theoretically and experimentally. Deficiencies of previous harmonic generation theories are pointed out and a nonlinear one-dimensional mathematical model, which includes the reactive nonlinearities due to the spatial variation of E, is developed. This nonlinear plasma capacitor model indicates that under certain electron-density and capacitor-plate spacing conditions strong harmonic resonances and an antiresonance are present. The antiresonance occurs when n ω = ω p and the resonances occur when n ω ≳ ω p , where ω p =plasma frequency, ω= the fundamental frequency, and n is the harmonic number. Harmonic generation in a number of gases is investigated experimentally in a coaxial discharge structure. Third-harmonic (9-GHz) efficiencies of up to 13 percent, and third-harmonic output power in excess of 600 mW are reported. Double-probe and microwave-scattering measurements show that enhanced harmonic generation occurs at the above resonances and, hence, substantiate the non-linear plasma capacitor theory. In order to explain the harmonic output power variations that occur with pressure variation and gas type, a graphical method of analysis based on experimental fact and pressure-collision frequency-electron energy curves is presented. This method of analysis not only yields results that compare qualitatively with experimental observations, but it may also possibly be used to design and predict the performance of future plasma frequency multipliers.
Mechanically tunable optofluidic distributed feedback dye laser.

A continuously tunable optofluidic distributed feedback (DFB) dye laser was demonstrated on a monolithic replica molded poly(dimethylsiloxane) (PDMS) chip. The optical feedback was provided by a phase-shifted higher order Bragg grating embedded in the liquid core of a single mode buried channel waveguide. Due to the soft elastomeric nature of PDMS, the laser frequency could be tuned by mechanically stretching the grating period. In principle, the mechanical tuning range is only limited by the gain bandwidth. A tuning range of nearly 60nm was demonstrated from a single dye laser chip by combining two common dye molecules Rhodamine 6G and Rhodamine 101. Single-mode operation was maintained with less than 0.1nm linewidth. Because of the higher order grating, a single laser, when operated with different dye solutions, can provide tunable light output covering the entire spectrum from near UV to near IR in which efficient laser dyes are available. An array of five DFB dye lasers with different grating periods was also demonstrated on a chip. Such tunable integrated laser arrays are expected to become key components in inexpensive advanced spectroscopy chips.
Bladder metastasis: A rare cause of hematuria in renal carcinoma

A case is presented in which gross hematuria was traced to bladder metas-tases. Although this clinical entity is extremely rare, it must be remembered to assure appropriate therapy, especially when hematuria is intractable and palliation is considered.
Syntheses, structures, physical properties, and theoretical studies of CeMxOS (M = Cu, Ag; x ≈ 0.8) and CeAgOS

Black single crystals of the two nonstoichiometric cerium coinage-metal oxysulfide compounds CeCu(x)OS and CeAg(x)OS (x approximately 0.8) have been prepared by the reactions of Ce2S3 and CuO or Ag2O at 1223 or 1173 K, respectively. A black powder sample of CeAgOS has been prepared by the stoichiometric reaction of Ce2S3, CeO2, Ag2S, and Ag at 1073 K. These isostructural materials crystallize in the ZrSiCuAs structure type with two formula units in the tetragonal space group P4/nmm. Refined crystal structure results and chemical analyses provide evidence that the previously known anomalously small unit-cell volume of LnCuOS for Ln = Ce (Ln = rare-earth metal) is the result of Cu vacancies and the concomitant presence of both Ce3+ and Ce4+. Both CeCu(0.8)OS and CeAgOS are paramagnetic with mu(eff) values of 2.13(6) and 2.10(1) mu(B), respectively. CeCu(0.8)OS is a p-type semiconductor with a thermal activation energy Ea = 0.22 eV, sigma(electrical) = 9.8(1) 10(-3) S/cm at 298 K, and an optical band gap Eg < 0.73 eV. CeAgOS has conductivity sigma(conductivity) = 0.16(4) S/cm and an optical band gap Eg = 0.71 eV at 298 K. Theoretical calculations with an on-site Coulomb repulsion parameter indicate that the Ce 4f states are fully spin-polarized and are not localized in CeCuOS, CeCu(0.75)OS, or CeAgOS. Calculated band gaps for CeCu(0.75)OS and CeAgOS are 0.6 and 0.8 eV, respectively.
On Smooth Time-Dependent Orbifolds and Null Singularities

We study string theory on a non-singular time-dependent orbifold of flat space. The orbifold group, which involves only space-like identifications, is obtained by a combined action of a null Lorentz transformation and a constant shift in an extra direction. In the limit where the shift goes to zero, the geometry of this orbifold reproduces an orbifold with a light-like singularity, which was recently studied by Liu, Moore and Seiberg (hep-th/0204168). We find that the backreaction on the geometry due to a test particle can be made arbitrarily small, and that there are scattering processes which can be studied in the approximation of a constant background. We quantize strings on this orbifold and calculate the torus partition function. We construct a basis of states on the smooth orbifold whose tree level string interactions are nonsingular. We discuss the existence of physical modes in the singular orbifold which resolve the singularity. We also describe another way of making the singular orbifold smooth which involves a sandwich pp-wave.
A Mid-Infrared Study of the Class 0 Cluster in LDN 1448

We present ground-based mid-infrared observations of Class 0 protostars in LDN 1448. Of the five known protostars in this cloud, we detected two, L1448N:A and L1448C, at 12.5, 17.9, 20.8, and 24.5 μm, and a third, L1448 IRS 2, at 24.5 μm. We present high-resolution images of the detected sources and photometry or upper limits for all five Class 0 sources in this cloud. With these data we are able to augment existing spectral energy distributions for all five objects and place them on an evolutionary status diagram.
Is silence golden? An inquiry into the meaning of silence in professional product evaluations

The world today is rife with product recommendations from professional critics and experts that are available from numerous sources—television, magazines, radio, internet, etc. Very often these recommendations shape our decisions and choices. In this study, we investigate two main issues regarding expert opinions. First, we present an approach that uses information available from every expert, including those who are silent about the product, to obtain a consensus measure of expert opinion. Our model also allows us to obtain a measure of how informative each expert is and how their information content may vary by type of review. More importantly, our overall measure of expert opinion weights the opinion of each expert based on how informative they are at the particular quality level of the product being evaluated. In other words, we provide consumers with a method that reconciles conflicting expert opinions into a summary measure. The second issue we investigate in this paper is the meaning of "silence" in expert opinions. Our model demonstrates that the fact that an expert is silent about a product may imply a positive or a negative review, depending on the expert. We use data from the motion pictures industry to illustrate our approach.
Reduction of Errors in Ceramic Bend Tests.

Abstract : Mechanical tests of most ceramics are subject to stringent requirements, more so than tests of materials which possess some ability to undergo plastic deformation. In this paper, sources of stress concentrations and spurious displacements which may be imposed during four-point bend tests of ceramic materials are identified and discussed. Particular areas of concern involve unequal moments at the loading points, twisting due to skewness of the contact lines, wedging stresses at point contacts, and counter moments produced by friction at the loading point-specimen interface. A bend fixture incorporating design features to significantly reduce these effects is described and results of measurements of the surface stresses in calibration specimens under load in the fixture are presented. (Author)
Pulsed-Laser-Induced Vibration of Pressurized Thin Walled Cylinder

Vibrations of a thin-walled pressurized cylinder, because of impulse loading induced by a high-energy pulsed laser beam, are investigated. Differential equations that describe cylinder oscillations for the case where variations in the axial direction are negligible are presented. The fluence profile of the incident beam is also assumed not to vary in the axial direction. Analytic expressions that provide the frequency and amplitude of the harmonic vibrational modes are derived. The computation of the laser-induced strain perturbation requires a numerical summation. Numerical results for induced hoop strain are given for both uniform and Gaussian beams.
α-(Dimethylamino)amides from a carbamoylsilane and iminium salts

The reaction of a carbamoylsilane with iminium salts derived from aldehydes lacking α-hydrogens affords the title compounds.
Association between red cell transfusions and necrotizing enterocolitis

Objective: Several case reports and retrospective studies have reported a temporal association between red blood cell (RBC) transfusions and necrotizing enterocolitis (NEC). In this article, we review the clinical evidence and biological plausibility of the association between RBC transfusions and NEC. Methods: A literature search was performed using the databases PubMed, EMBASE, and Scopus, and the electronic archive of abstracts presented at the annual meetings of the Pediatric Academic Societies. Results: Among all cases of NEC, 25 -40% patients were noted to have received an RBC transfusion within a 48 hour period prior to onset of NEC. Compared to infants who developed NEC unrelated to transfusion, neonates with transfusion-associated NEC were born at an earlier gestation, had lower birth weights, and had a delayed onset at 3–5 weeks of postnatal age. Conclusions: Based on current clinical evidence, transfusion-associated NEC appears to be a plausible clinical entity. However, there is a need for cau...
Nitrogen-Fixing Winter Cover Crops and Production Risk: A Case Study for No-Tillage Corn

Winter legumes can substitute for applied nitrogen fertilization of corn. Stochastic dominance was used to order net revenues from legume and applied nitrogen alternatives. Stochastic dominance orderings indicate that systems combining vetch with low applied nitrogen fertilization (50 and 100 pounds/acre, respectively) were risk inefficient. By contrast, vetch and 150 pounds acre applied nitrogen maximized expected net revenue and was risk efficient for a wide range of risk-averse and risk-seeking behavior. Farmers with these risk attitudes may not reduce applied nitrogen if they switch to a vetch cover. Extremely risk-averse or risk-seeking farmers would not prefer winter legumes.
Identifying sources of reporting error using measured food intake.

To investigate the magnitude and relative contribution of different sources of measurement errors present in the estimation of food intake via the 24-h recall technique. We applied variance decomposition methods to the difference between data obtained from the USDA's Automated Multiple Pass Method (AMPM) 24-h recall technique and measured food intake (MFI) from a 16-week cafeteria-style feeding study. The average and the variance of biases, defined as the difference between AMPM and MFI, were analyzed by macronutrient content, subject and nine categories of foods. Twelve healthy, lean men (age, 39±9 year; weight, 79.9±8.3 kg; and BMI, 24.1±1.4 kg/m2). Mean food intakes for AMPM and MFI were not significantly different (no overall bias), but within-subject differences for energy (EI), protein, fat and carbohydrate intakes were 14, 18, 23 and 15% of daily intake, respectively. Mass (incorrect portion size) and deletion (subject did not report foods eaten) errors were each responsible for about one-third of the total error. Vegetables constituted 8% of EI but represented >25% of the error across macronutrients, whereas grains that contributed 32% of EI contributed only 12% of the error across macronutrients. Although the major sources of reporting error were mass and deletion errors, individual subjects differed widely in the magnitude and types of errors they made.
Time-dependent Photoionization of Gaseous Nebulae: The Pure Hydrogen Case

We study the problem of time-dependent photoionization of low density gaseous nebulae subjected to sudden changes in the intensity of ionizing radiation. To this end, we write a computer code that solves the full timedependent energy balance, ionization balance, and radiation transfer equations in a self-consistent fashion for a simplified pure hydrogen case. It is shown that changes in the ionizing radiation yield ionizationthermal fronts that propagate through the cloud, but the propagation times and response times to such fronts vary widely and nonlinearly from the illuminated face of the cloud to the ionization front (IF). IFthermal fronts are often supersonic, and in slabs initially in pressure equilibrium such fronts yield large pressure imbalances that are likely to produce important dynamical effects in the cloud. Further, we studied the case of periodic variations in the ionizing flux. It is found that the physical conditions of the plasma have complex behaviors that differ from any steady-state solution. Moreover, even the time average of ionization and temperature is different from any steady-state case. This time average is characterized by overionization and a broader IF with respect to the steady-state solution for a mean value of the radiation flux. Around the time average of physical conditions there is a large dispersion in instantaneous conditions, particularly across the IF, which increases with the period of radiation flux variations. Moreover, the variations in physical conditions are asynchronous along the slab due to the combination of nonlinear propagation times for thermal frontsIFs and equilibration times.
Running unstructured grid‐based CFD solvers on modern graphics hardware

Techniques used to implement an unstructured grid solver on modern graphics hardware are described. The three-dimensional Euler equations for inviscid, compressible ow are considered. Eective memory bandwidth is improved by reducing total global memory access and overlapping redundant computation, as well as using an appropriate numbering scheme and data layout. The applicability of per-block shared memory is also considered. The performance of the solver is demonstrated on two benchmark cases: a missile and the NACA0012 wing. For a variety of mesh sizes, an average speed-up factor of roughly 9.5x is observed over the equivalent parallelized OpenMP-code running on a quad-core CPU, and roughly 33x over the equivalent code running in serial.
What motivates entrepreneurial entry under economic inequality? The role of human and financial capital

Based on a multilevel analysis of nearly 120,000 observations across 31 countries between 2001 and 2008, we provide novel insights into the moderating effects that economic inequality may have on the distinct roles that human and financial capital play on different types of entrepreneurship. As inequality increases, both forms of capital become weaker deterrents of entry into necessity entrepreneurship, whereas for opportunity entrepreneurship, only financial capital becomes a stronger predictor of entry. We also show that, regardless of inequality levels, both human and financial capital exhibit decreasing marginal returns on the likelihood of entry into necessity entrepreneurship, and that in the case of opportunity entrepreneurship, financial capital exhibits increasing marginal returns. However, inequality does impact the magnitude of marginal returns. Additionally, our statistical analysis provides quantitative support to extant literature arguing that higher levels of economic inequality foster both types of entrepreneurship albeit having a stronger impact on necessity entrepreneurship, and that human and financial capital have distinct effects on entry into necessity versus opportunity entrepreneurship. All these findings have pertinent policy implications and shed light on the under-researched role of inequality on entrepreneurship.
Atomic layer deposition synthesis of platinum–tungsten carbide core–shell catalysts for the hydrogen evolution reaction

Pt was deposited onto tungsten carbide powders using atomic layer deposition to produce core–shell catalysts for the hydrogen evolution reaction (HER). The Pt loading on these catalysts was reduced nearly ten-fold compared to a bulk Pt catalyst while equivalent HER activities were observed.
Laurent phenomenon sequences

In this paper, we undertake a systematic study of sequences generated by recurrences $$x_{m+n}x_m = P(x_{m+1}, \ldots , x_{m+n-1})$$xm+nxm=P(xm+1,?,xm+n-1) which exhibit the Laurent phenomenon. Some of the most famous among these are the Somos and the Gale-Robinson sequences. Our approach is based on finding period 1 seeds of Laurent phenomenon algebras of Lam---Pylyavskyy. We completely classify polynomials P that generate period 1 seeds in the cases of $$n=2,3$$n=2,3 and of mutual binomial seeds. We also find several other interesting families of polynomials P whose generated sequences exhibit the Laurent phenomenon. Our classification for binomial seeds is a direct generalization of a result by Fordy and Marsh, that employs a new combinatorial gadget we call a double quiver.