cssi/SciSciGPT-SciSciNet huggingface dataset:
Chandra study of young stellar objects in the NGC 1333 star-forming cloud

NGC 1333, a highly active star formation region within the Perseus molecular cloud complex, has been observed with the ACIS-I detector on board the Chandra X-Ray Observatory. In our image with a sensitivity limit of ~1028 ergs s-1, we detect 127 X-ray sources, most with subarcsecond positional accuracy. While 32 of these sources appear to be foreground stars and extragalactic background, 95 X-ray sources are identified with known cluster members. The X-ray luminosity function of the discovered young stellar object (YSO) population spans a range of log LX 28.0-31.5 ergs s-1 in the 0.5-8 keV band, and absorption ranges from log NH 20 to 23 cm-2. Most of the sources have plasma energies between 0.6 and 3 keV, but a few sources show higher energies up to ~7 keV. Comparison with K-band source counts indicates that we detect all of the known cluster members with K 12. K 11, the peak of the K-band luminosity function, corresponds to 0.2-0.4 M☉ stars for a cluster age of ~1 Myr. We detect seven of the 20 known YSOs in NGC 1333 producing jets or molecular outflows as well as one deeply embedded object without outflows. No evident difference in X-ray emission of young stars with and without outflows is found. Based on the complete subsample of T Tauri stars, we also find no difference in X-ray properties and X-ray production mechanism of stars with and without K-band excess disks. Several other results are obtained. We suggest that the X-ray emission from two late B stars that illuminate the reflection nebula originates from unresolved late-type companions. Two T Tauri stars are discovered in the ACIS images as previously unknown components of visual binaries. A good correlation LX J is seen, which confirms the well-known relation LX Lbol found in many star-forming regions. Based on spectral analysis for the X-ray counterpart of SVS 16, we establish that the column density NH is much lower than that expected from near-IR photometry so that its X-ray luminosity, log LX 30.6 ergs s-1, is not unusually high.
Metal Carbonyl Anions: from [Fe(CO)4]2- to [Hf(CO)6]2- and Beyond†

A chronological survey of the syntheses and characterizations of homoleptic mononuclear metal carbonyl anions is presented, from the first isolated example, [Fe(CO)4]2-, to the most recently reported species, [Hf(CO)6]2-. These materials are of historical interest, since they are the first compounds to contain transition metals in formal negative oxidation states, but remain important reagents in all areas of chemical synthesis and often closely resemble electron-rich nonmetallic compounds in their ability to function as Lewis and Bronsted bases, nucleophiles, and/or reducing agents. Prospects for the syntheses of new carbonyl anions for the very early and late transition metals and the lanthanides and actinides are also discussed.
Ghosts as negative spinors

We study the properties of a BRST ghost degree of freedom complementary to a two-state spinor. We show that the ghost may be regarded as a unit carrier of negative entropy. We construct an irreducible representation of the su(2) Lie algebra with negative spin, equal to −12, on the ghost state space and discuss the representation of finite SU(2) group elements. The Casimir operator J2 of the combined spinor–ghost system is nilpotent and coincides with the BRST operator Q. Using this, we discuss the sense in which the positive and negative spin representations cancel in the product to give an effectively trivial representation. We compute an effective dimension, equal to 12, and character for the ghost representation and argue that these are consistent with this cancellation.
PROPAGATING COVARIANCE IN COMPUTER VISION

This paper describes how to propagate approximately additive random perturbations through any kind of vision algorithm step in which the appropriate random perturbation model for the estimated quantity produced by the vision step is also an additive random perturbation. We assume that the vision algorithm step can be modeled as a calculation (linear or non-linear) that produces an estimate that minimizes an implicit scaler function of the input quantity and the calculated estimate. The only assumption is that the scaler function has finite second partial derivatives and that the random perturbations are small enough so that the relationship between the scaler function evaluated at the ideal but unknown input and output quantities and the observed input quantity and perturbed output quantity can be approximated sufficiently well by a first order Taylor series expansion. The paper finally discusses the issues of verifying that the derived statistical behavior agrees with the experimentally observed statistical behavior.
Scope and Limitations of the Pd/BINAP-Catalyzed Amination of Aryl Bromides

Mixtures of Pd2(dba)3 or Pd(OAc)2 and BINAP catalyze the cross-coupling of amines with a variety of aryl bromides. Primary amines are arylated in high yield, and certain classes of secondary amines are also effectively transformed. The process tolerates the presence of several functional groups including methyl and ethyl esters, enolizable ketones, and nitro groups provided that cesium carbonate is employed as the base. Most reactions proceed to completion with 0.5−1.0 mol % of the palladium catalyst; in some cases, catalyst levels as low as 0.05 mol % Pd may be employed. Reactions are considerably faster if Pd(OAc)2 is employed as the precatalyst, and the order in which reagents are added to the reaction has a substantial effect on reaction rate. It is likely that the catalytic process proceeds via bis(phosphine)palladium complexes as intermediates. These complexes are less prone to undergo undesirable side reactions which lead to diminished yields or catalyst deactivation than complexes of the correspon...
Interjurisdictional Capital Mobility: Fiscal Externality and a Corrective Subsidy

Abstract Recent studies emphasize that local property taxation may result in inefficiently small amounts of local public spending. This paper shows that the inefficiency can be traced to a fiscal externality: when one jurisdiction increases its taxes, it causes a flow of capital to other jurisdictions that increases their tax revenues. The inefficiency can be corrected with a subsidy that internalizes the externality. Key empirical parameters determining the magnitude of the externality are identified. Illustrative calculations indicate that subsidy rates on the order of 40% might be required to achieve efficiency.
The Conceptual Foundations of the New International Division of Labor

This article appraises the conceptual foundations of the new international division of labor (NIDL) literature. According to NIDL, the observed shift of international production from developed to l...
A linear space algorithm for computing the hermite normal form

Computing the Hermite Normal Form of an n × n integer matrix using the best current algorithms typically requires O(n3 log M) space, where M is a bound on the entries of the input matrix. Although polynomial in the input size (which is O(n2 log M)), this space blow-up can easily become a serious issue in practice when working on big integer matrices. In this paper we present a new algorithm for computing the Hermite Normal Form which uses only O(n2 log M) space (i.e., essentially the same as the input size). When implemented using standard algorithms for integer and matrix multiplication, our algorithm has the same time complexity of the asymptotically fastest (but space inefficient) algorithms. We also present a heuristic algorithm for HNF that achieves a substantial speedup when run on randomly generated input matrices.
Asymmetric Hydrovinylation of 1-Vinylcycloalkenes. Reagent Control of Regio- and Stereoselectivity

1-Vinylcycloalkenes undergo highly regio- and enantioselective (>98% ee) 1,4-hydrovinylation (HV) when treated with ethylene (1 atm) at room temperature in the presence of [(S,S)-2,4-bis-diphenylphosphinopentane (BDPP)]CoCl2 (0.05 equiv) and methylaluminoxane. The minor 1,2-HV products, seen only in 1-vinylcyclohexene (∼15%) and 1-vinylcycloheptene (2%), are formed as racemic mixtures. The corresponding Ni(II)-catalyzed HV reactions of these substrates give mostly the 1,2-adducts. Racemic 4-tert-butyl-1-vinylcyclohexene, when treated with Co[(S,S)-(BDPP)]Cl2 and ethylene, undergoes a rare enantiodivergent reaction giving two diastereomers each in >98% ee.
A-Model correlators from the Coulomb branch

We compute the contribution of discrete Coulomb vacua to A-Model correlators in toric Gauged Linear Sigma Models. For models corresponding to a compact variety, this determines the correlators at arbitrary genus. For non-compact examples, our results imply the surprising conclusion that the quantum cohomology relations break down for a subset of the correlators.
The Abundances of Light Neutron-Capture Elements in Planetary Nebulae. II. s-Process Enrichments and Interpretation*

We present the results of a large-scale survey of neutron(n)-capture elements in Galactic planetary nebulae (PNe), undertaken to study enrichments from s-process nucleosynthesis in their progenitor stars. From new K-band observations of over 100 PNe supplemented by data from the literature, we have detected the emission lines [Kr III] 2.199 μm and/or [Se IV] 2.287 μm in 81 of 120 objects. We determine Se and Kr elemental abundances, employing ionization correction formulae derived in the first paper of this series. We find a significant range in Se and Kr abundances, from near solar (no enrichment) to enhanced by >1.0 dex relative to solar, which we interpret as self-enrichment due to in situ s-process nucleosynthesis. Kr tends to be more strongly enriched than Se; in 18 objects exhibiting both Se and Kr emission, we find that [ Kr/Se ] = 0.5 ± 0.2. Our survey has increased the number of PNe with n-capture element abundance determinations by a factor of 10, enabling us for the first time to search for correlations with other nebular properties. As expected, we find a positive correlation between s-process enrichments and the C/O ratio. Type I and bipolar PNe, which arise from intermediate-mass progenitors (>3-4 M☉), exhibit little to no s-process enrichments. Finally, PNe with H-deficient Wolf-Rayet central stars do not exhibit systematically larger s-process enrichments than objects with H-rich nuclei. Overall, 44% of the PNe in our sample display significant s-process enrichments (>0.3 dex). Using an empirical PN luminosity function to correct for incompleteness, we estimate that the true fraction of s-process enriched Galactic PNe is at least 20%.
Acute enterocyte adaptation to luminal glucose: a posttranslational mechanism for rapid apical recruitment of the transporter GLUT2.

Background Glucose absorption postprandially increases markedly to levels far greater than possible by the classic glucose transporter sodium–glucose cotransporter 1 (SGLT1).
Communication in the raid distributed database system

Abstract This paper identified the basic services required from a communication subsystem to support a distributed, reliable, reconfigurable, and replicated database environment. These services include multicasting, remote procedure calls (RPC), inexpensive data-gram services, and efficient local interprocess communication (IPC). Data are included from experiments that measure communication performance in four areas: (i) layered implementations of communication protocols, (ii) local interprocess communication methods, (iii) multicasting, and (iv) commitment processing. We have used the results of those experimental studies to design and implement a new communication facility. It features an unobtrusive IPC paradigm and a transaction-oriented multicasting mechanism.
Using shape distributions as priors in a curve evolution framework

In this paper we propose a framework of constructing and using a shape prior in estimation problems. The key novelty of our technique is a new way to use high level, global shape knowledge to derive a local driving force in a curve evolution context. We capture information about shape in the form of a family of shape distributions (cumulative distribution functions) of features related to the shape. We design a prior objective function that penalizes the differences between model shape distributions and those of an estimate. We incorporate this prior in a curve evolution formulation for function minimization. Shape distribution-based representations are shown to satisfy several desired properties, such as robustness and invariance. They also have good discriminative and generalizing properties. To our knowledge, shape distribution-based representations have only been used for shape classification. Our work represents the development of a tractable framework for their incorporation in estimation problems. We apply our framework to three applications: shape morphing, average shape calculation, and image segmentation.
Finite radiative electroweak symmetry breaking from the bulk

Abstract A new physical origin for electroweak symmetry breaking is proposed, involving compact spatial dimensions of scale 1/ R ≈1 TeV. The higher-dimensional theory is supersymmetric, and hence requires the top-quark Yukawa coupling to be localized on some “Yukawa brane” in the bulk. The short distance divergence in the Higgs-boson mass is regulated because supersymmetry is unbroken in the vicinity of this Yukawa brane. A finite , negative Higgs mass-squared is generated radiatively by the top-quark supermultiplet propagating a distance of order R from the Yukawa brane to probe supersymmetry breaking. The physics of electroweak symmetry breaking is therefore closely related to this top propagation across the bulk, and is dominated by the mass scale 1/ R , with exponential insensitivity to higher energy scales. The masses of the superpartners and the Kaluza–Klein resonances are also set by the mass scale 1/ R , which is naturally larger than the W boson mass by a loop factor. Explicit models are constructed which are highly constrained and predictive. The finite radiative correction to the Higgs mass is computed, and the Higgs sector briefly explored. The superpartner and Kaluza–Klein resonance spectra are calculated, and the problem of flavor violation from squark and slepton exchange is solved. Important collider signatures include highly ionizing charged tracks from stable top squarks, and events with two Higgs bosons and missing transverse energy.
Experimental evidence for the pentaquark

The present experimental evidence for the existence of light pentaquarks is reviewed, including both positive and null results. I also discuss the CLAS experiments at Jefferson Laboratory that are forthcoming in the near future to address questions regarding existence, mass, width, and other quantum numbers of these five-quark baryon states. PACS: 12.39.Mk Glueball and nonstandard multi-quark/gluon states – 14.20.-c Baryons – 14.80.-j Other particles
Thermal and chemical variations in subcrustal cratonic lithosphere: Evidence from crustal isostasy

Abstract The Earth's topography at short wavelengths results from active tectonic processes, whereas at long wavelengths it is largely determined by isostatic adjustment for the density and thickness of the crust. Using a global crustal model, we estimate the long-wavelength topography that is not due to crustal isostasy. Our most important finding is that cratons are generally depressed by 300 to 1500 m in comparison with predictions from pure crustal isostasy. We conclude that either: (1) cratonic roots may be 50 to 300 °C colder than previously suggested by thermal models, or (2) cratonic roots may be, on average, less depleted than suggested by studies of shallow mantle xenoliths. Alternatively, (3) some combination of these conditions may exist. The thermal explanation is consistent with recent geothermal studies that indicate low cratonic temperatures, as well as seismic studies that show very low seismic attenuation at long periods (150 s) beneath cratons. The petrologic explanation is consistent with recent studies of deep (>140 km) mantle xenoliths from the Kaapvaal and Slave cratons that show 1–2% higher densities compared with shallow (
Fluctuation induced first order phase transitions

Abstract We study a U ( N ) × U ( N ) symmetric scalar field model in four and three dimensions. First, using our data in four dimensions in the weak coupling region, we demonstrate explicitly that the observed first order phase transition is induced by quantum fluctuations. Next, based on the renormalization group and our new simulation results in three dimensions we argue that even if the U A (1) symmetry is restored below the critical temperature the QCD finite temperature chiral phase transition for two flavor could be extremely weak first order.
Strongly interacting isotopic Bose-Fermi mixture immersed in a Fermi sea

We have created a triply quantum-degenerate mixture of bosonic $^{41}\mathrm{K}$ and two fermionic species $^{40}\mathrm{K}$ and $^{6}\mathrm{Li}$. The boson is shown to be an efficient coolant for the two fermions, spurring hopes for the observation of fermionic superfluids with imbalanced masses. We observe multiple heteronuclear Feshbach resonances, in particular a wide $s$-wave resonance for the combination $^{41}\mathrm{K}$-$^{40}\mathrm{K}$, opening up studies of strongly interacting isotopic Bose-Fermi mixtures. For large imbalance in the local densities of different species, we enter the polaronic regime of dressed impurities immersed in a bosonic or fermionic bath.
Archives and Memory

Archives are repositories of memory, providing reliable evidence for examining the past. The four types of memory – personal, collective, historical, and archival – interact in complex and sometimes baffling ways to enable one to understand the past and to draw lessons from it. Archival memory is a social construct reflecting power relationships in society. Archivists and manuscripts curators play the important role of mediator in selecting records for preservation and providing research access to such collections. By recognizing and overcoming the bias toward records of powerful groups in society, archivists can provide a more balanced perspective on the past, and enable future generations to examine and evaluate the activities and contributions of all voices in one’s culture. Archives thus serve an important role in identifying and preserving the documentation that forms one’s historical memory.
Neutron-induced collision cascade mixing in Nb/V superlattices

Abstract High-angle X-ray diffraction was used to determine cascade mixing efficiencies, Dt/dpa, in Nb/V superlattices irradiated to small doses (≤ 0.26 dpa). Samples were neutron irradiated in the core of the High Flux Beam Reactor at Brookhaven National Laboratory and ion irradiated with 1.5 MeV Ne. No significant differences were observed in cascade mixing efficiencies between the two types of irradiation. Values of Dt/dpa were observed to vary with the modulation wavelength of the superlattice, with thicker wavelength samples yielding values approaching that determined from ion mixing thick Nb/V bilayers ( Dt/ dpa ∼ 110 A 2 / dpa ) . The decrease in mixing efficiency observed at lower wavelengths may be related to an observed structural transition in which the interfaces of the superlattice become coherent.
Quantile regression under random censoring

Censored regression models have received a great deal of attention in both the theoretical and applied econometric literature. Most of the existing estimation procedures for either cross-sectional or panel data models are designed only for models with fixed censoring. In this paper, a new procedure for adapting these estimators designed for fixed censoring to models with random censoring is proposed. This procedure is then applied to the CLAD and quantile estimators of Powell (J. Econom. 25 (1984) 303, 32 (1986a) 143) to obtain an estimator of the coefficients under a mild conditional quantile restriction on the error term that is applicable to samples exhibiting fixed or random censoring. The resulting estimator is shown to have desirable asymptotic properties, and performs well in a small-scale simulation study.
A demonstration of MEMS-based active turbulence transitioning

Abstract At Re=25 000 an active transition to turbulence was demonstrated on a cylinder equipped with flush mounted micro-electro-mechanical-systems (MEMS) shear stress sensor arrays and a thin spanwise slit for internal acoustic perturbations. MEMS hot film sensor arrays measured separation and vortex shedding data which were used to aim and tune acoustic perturbations to the boundary layer; this produced an instability-driven acceleration of the transition process. Perturbations tuned to the instability frequencies (Strouhal number of 2 at Re=25 000 ) and directed at the separation point achieved dramatically higher root-mean-square (RMS) fluctuation levels, thereby delaying separation and reducing wake velocity delicits of the cylinder. Time histories and spectral analysis map the amplification of the input disturbances by the shear layer instability.
Palladium-catalyzed annulation of vinylic cyclopropanes and cyclobutanes

Abstract Aryl iodides substituted in the ortho position by OH, CH2OH, NH2, NHTs and CH(CO2Et)2 groups react with vinylic cyclopropanes and cyclobutanes in the presence of a palladium catalyst and an appropriate base to afford good yields of heterocycles and carbocycles. The annulation products apparently arise by (1) palladium(0) formation and insertion into the carbon-iodine bond of the aryl iodide to generate an arylpalladium intermediate, (2) arylpalladium addition across the carbon-carbon double bond of the alkene, (3) ring-opening of the cyclopropane or cyclobutane by carbon-palladium beta elimination, (4) rearrangement of the resulting unsaturated alkylpalladium compound to a π-allylpalladium compound by a series of reversible palladium hydride beta elimination and readdition steps, (5) anion formation by removal of a proton from the functional group present on the arene, and (6) nucleophillic substitution of the palladium by the resulting anion.
Vibration Control Of Flexible Spacecraft Integrating A Momentum Exchange Controller And A Distributed Piezoelectric Actuator

Abstract This investigation is to apply the so-called momentum exchange feedback control concept and distributed piezoelectric actuator technology to the vibration control of a flexible spacecraft. The flexible model to be investigated is a rigid hub with a cantilever flexible beam appendage which can undergo a single axis rotation. The proposed control system includes the attitude controller acting on the rigid hub, designed by the momentum exchange feedback control concept, and the uniform piezoelectric film actuator bonded on the surface of the beam appendage, designed by the state space LQR technique. The rationale for this hybrid control scheme is that the momentum exchange feedback controller acting on the rigid hub can suppress the relatively large amplitude vibrations excited by, for example, rapid maneuvers or other large disturbances, whereas the piezoelectric film actuator is more suitable for suppression of microvibrations, i.e., fine tuning of the system at the final stage of operation, which is important for precision pointing or shape control. Therefore, by combining the advantages of both controllers, an improved performance for vibration control in both the macro- and micro-senses can result.
Conjugative effects in dicarbonyl compounds. the vibrational spectra and structures of trans-3- carbomethoxypropenoic acid (monomethyl fumarate) and its sodium salt

Abstract The complete infrared and Raman spectra of monomethyl fumarate have been recorded. Monomethyl fumarate-O-d I and sodium monomethyl fumarate have been synthesized and their infrared spectra recorded. These data have been used to carry out a tentative vibrational assignment of monomethyl fumarate. The frequencies of the carbonyl stretching modes and the olefinic carbon-carbon stretching modes are considered in some detail and compared with the corresponding modes in similar molecules. This has allowed conclusions to be drawn concerning the conjugative interactions present in these molecules. It is concluded that conjugative interactions, if present, are not important factors in the determination of the absorption frequencies of these vibrational modes in the fumarate series.
Reliability-Based Structural Optimization of an Elastic-Plastic Beam

The application of reliability-based optimization to an elastic-plastic beam is studied. The objective is to demonstrate the benefits of reliability-based optimization over the deterministic optimization in such applications where the design requirements of the member tolerate some plastic behavior. Also, some of the difficulties that one might encounter while performing reliability-based optimization of elastic-plastic beams are addressed. A graphical method was used here to avoid the problems of high nonlinearity and derivative discontinuity of the reliability function. The method starts by obtaining a deterministic optimum design that has the lowest possible weight for a prescribed safety factor, and, based on that design, the method obtains an improved optimum design that has either a higher reliability or a lower weight or cost. In this application three failure modes are considered for an elastic-plastic beam of T cross section under combined axial, bending, and shear loads. The failure modes are based on the beam total plastic failure in a section, buckling, and maximum allowable deflection. The results show that it is possible to get improved optimum designs (more reliable or lighter) using reliability-based optimization as compared to the design given by deterministic optimization. Also, the results show that the reliability function can be highly nonlinear with respect to the design variables with discontinuous derivatives.
Whither Stakeholder Theory? A Guide for the Perplexed Revisited

The nature of stakeholder theory and its fundamental normative prescriptions are the subject of much confusion and academic debate. This article attempts to provide an account of both the fundamental normative implications of stakeholder theory and the theory’s range of application that both stakeholder advocates and critics can agree upon. Using exclusively the language of leading stakeholder theorists, the article identifies the essential prescriptions of the theory and the type of organizations to which stakeholder theory applies in the hope of facilitating effective discussion and evaluation of the normative dimension of stakeholder theory.
Physical Design Tools Support and Hinder Innovative Engineering Design

Engineers use various physical tools (e.g., computers, smart boards, notes, and proto-types) to support their design work. To understand cognitive processes underlying theinnovative design process and to reveal the characteristics of innovation-supporting envi-ronments, we examined the pattern of tool use in 43 interdisciplinary engineering designteams enrolled in a full-semester product realization course. Teams worked all semesteron a single project, with each team being assigned a different industry-sponsored project.Group meetings were video-recorded. Team success was measured in terms of meetingclient requirements, and groups were divided into high, medium, and low success. Suc-cessful teams (i.e., high and medium success groups) were found to use a smart boardand physical prototypes consistently more often throughout the design process, whereasunsuccessful teams (i.e., low success group) used a computer, laptop, and paper notesmore often. Particularly, late adoption of physical prototypes was a key characteristic ofunsuccessful teams. [DOI: 10.1115/1.4005651]Keywords: design tools, analogies, mental simulation, engineering design
Energy prices and the expansion of world trade

Abstract The share of merchandise output that is internationally traded has significantly increased while tariffs have fallen. However, standard trade models have surprising difficulty linking these two facts. Trade growth slowed in the 1970s as tariffs fell relatively sharply while after the late 1980s trade grew quickly as tariffs fell slowly. This pattern implies that the price-import elasticity has changed over time. Also, tariffs have not fallen enough to generate such a large increase in trade given estimates of this elasticity. Changes in transport costs can resolve both puzzles. I present a vertical specialization trade model with an energy-using transportation sector. In the simulated model, trade growth slows from 1974 to 1985. The oil shocks raised transport costs, offsetting falling tariffs, so the price-import elasticity no longer needs to change. It also generates the observed volume of trade growth since transport costs have fallen over the long run.
Field-Effect Transistors Assembled From Functionalized Carbon Nanotubes

We have fabricated field-effect transistors from carbon nanotubes using a novel selective placement scheme. We use carbon nanotubes that are covalently bound to molecules containing a hydroxamic acid functionality. The functionalized nanotubes bind strongly to basic metal oxide surfaces, but not to silicon dioxide. Upon annealing, the functionalization is removed, restoring the electronic properties of the nanotubes. The devices thus fabricated show excellent electrical characteristics.
Prediction of the Aerodynamic Environment and Heat Transfer for Rotor-Stator Configurations

A numerical study of the aerodynamic and thermal environment associated with axial turbine stages is presented. Computations were performed using a modification of the unsteady viscous code, ROTORI, and an improved version of the steady inviscid cascade system, MERIDL-TSONIC, coupled with boundary layer codes, BLAYER and STAN5. Two different turbine stages were analyzed: the first stage of the United Technologies Research Center Large Scale Rotating Rig (LSRR) and the first stage of the Space Shuttle Main Engine (SSME) high pressure fuel turbopump turbine. The time-averaged airfoil midspan pressure and heat transfer profiles were predicted for numerous thermal boundary conditions including adiabatic wall, prescribed surface temperature, and prescribed heat flux. Computed solutions are compared with each other and with experimental data in the case of the LSRR calculations. Modified ROTORI predictions of unsteady pressure envelopes and instantaneous contour plots are also presented. Relative merits of the two computational approaches are discussed.
A Semantic-Based Dynamic Search Engine Design and Implementation for Electronic Medical Records

In the current technology driven world, information retrieval activities are in almost every aspect of daily, as society uses popular web search engines like Google, Yahoo!, Live Search, Ask, and so forth to obtain helpful information. Often, these popular search engines look for and obtain key information; however, not all of the retrieved items are relevant in context to the search target a. Thus, it is left for the user to filter out unwanted information, using only a few information items left from the search results. These popular web search engines use a first generation search service based on "static keywords", which require the users to know exactly what they want to search and enter the right keywords. This approach puts the user at a disadvantage. In this paper, the authors investigate and design a dynamic, question-answer search engine that enables searching by attributes for more precise and relevant information in Electronic Medical Record EMR field.
A Randomized Kaczmarz Algorithm with Exponential Convergence

The Kaczmarz method for solving linear systems of equations is an iterative algorithm that has found many applications ranging from computer tomography to digital signal processing. Despite the popularity of this method, useful theoretical estimates for its rate of convergence are still scarce. We introduce a randomized version of the Kaczmarz method for consistent, overdetermined linear systems and we prove that it converges with expected exponential rate. Furthermore, this is the first solver whose rate does not depend on the number of equations in the system. The solver does not even need to know the whole system but only a small random part of it. It thus outperforms all previously known methods on general extremely overdetermined systems. Even for moderately overdetermined systems, numerical simulations as well as theoretical analysis reveal that our algorithm can converge faster than the celebrated conjugate gradient algorithm. Furthermore, our theory and numerical simulations confirm a prediction of Feichtinger et al. in the context of reconstructing bandlimited functions from nonuniform sampling.
A composite little Higgs model

We describe a natural UV complete theory with a composite little Higgs. Below a TeV we have the minimal Standard Model with a light Higgs, and an extra neutral scalar. At the TeV scale there are additional scalars, gauge bosons, and vector-like charge 2/3 quarks, whose couplings to the Higgs greatly reduce the UV sensitivity of the Higgs potential. Stabilization of the Higgs mass squared parameter, without finetuning, occurs due to a softly broken shift symmetry — the Higgs is a pseudo Nambu-Goldstone boson. Above the 10 TeV scale the theory has new strongly coupled interactions. A perturbatively renormalizable UV completion, with softly broken supersymmetry at 10 TeV is explicitly worked out. Our theory contains new particles which are odd under an exact ``dark matter parity, (−1)(2S+3B+L). We argue that such a parity is likely to be a feature of many theories of new TeV scale physics. The lightest parity odd particle, or ``LPOP, is most likely a neutral fermion, and may make a good dark matter candidate, with similar experimental signatures to the neutralino of the MSSM. We give a general effective field theory analysis of the calculation of corrections to precision electroweak observables.
Flow-induced vibration in LMFBR steam generators: A state-of-the-art review

Abstract This state of the art review identifies and discusses existing methods of flow-induced vibration analysis applicable to steam generators, their limitations and base-technology needs. Also included are discussions of five different LMFBR steam generator configurations and important design considerations, failure experiences, possible flow-induced excitation mechanisms, vibration testing and available methods of vibration analysis. The objectives are to aid LMFBR steam generator designers in making the best possible evaluation of potential vibration in steam generator internals, and to provide the basis for development of design guidelines to avoid detrimental flow-induced vibration.
Group selective radical cyclizations with Oppolzer's camphor sultam

Abstract Acyl derivatives of Oppolzer's camphor sultam provide moderate levels of group selectivity (≈85/15) in representative radical cyclizations of dienes and diynes.
Enantioselective allene/enone photocycloadditions: The use of an inexpensive optically active 1,3-disubstituted allene

Abstract We report the preparation and use of an inexpensive readily prepared optically active 1,3-disubstituted allene that may be utilized for enantioselective intramolecular allene/enone photocycloadditions. In addition, we describe novel substrates for intramolecular [2+2] photocycloadditions which substantially expand the scope of the process to include amino- and thio- tethered allene/enones.
A new ternary nitride La2GaN3: Synthesis and crystal structure

Abstract The ternary nitride La2GaN3 was synthesized at 900 °C from the elements with an excess of sodium and gallium in a sealed niobium tube. La2GaN3 is yellow colored and crystallizes with the Ba2ZnO3 structure [monoclinic space group C2/c (No. 15), a = 5.6709(5) A, b = 10.945(1) A, c = 11.986(1) A, β = 93.591(5)°, V = 742.54(12) A3, Z = 8] and is isostructural with the A2IIMVN3 nitrides, Sr(Ba)2TaN3, Sr(Ba)2NbN3, Ca(Sr)2VN3. The structure contains infinite chains of GaN4 tetrahedral anions, [ Ga N 2 N 2 / 2 ] 6 − ∞ 1 .
MISSIONS TO THE SUN

Almost all space disturbances start at the Sun. David Rust examines how we study our most important star and what can be learned from the data retrieved from solar instruments.
Dark matter halo growth - II. Diffuse accretion and its environmental dependence

Dark matter haloes in ACDM simulations grow by mergers with other haloes as well as accretion of 'diffuse' non-halo material. We quantify the mass growth rates via these two processes, M mer and M dif , and their respective dependence on the local halo environment using the ∼500 000 haloes of mass ∼10 12 to 10 15 M ⊙ in the Millennium simulation. Adopting a local mass density parameter as a measure of halo environment, we find the two rates to show strong but opposite environmental dependence, with mergers playing an increasingly important role for halo growths in overdense regions while diffuse accretion dominating the growth in the voids. For galaxy-scale haloes, these two opposite correlations largely cancel out, but a weak environmental dependence remains that results in a slightly lower mean total growth rate, and hence an earlier mean formation redshift, for haloes in denser environments. The mean formation redshift of cluster-mass haloes, on the other hand, shows no correlation with halo environment. The origin of the positive correlation of M mer with local density can be traced to the surrounding mass reservoir outside the virial radii of the haloes, where more than 80 per cent of the mass is in the form of resolved haloes for haloes residing in densest regions, while this fraction drops to ∼20 per cent in the voids. The negative correlation of M dif with local density, however, is not explained by the available diffuse mass in the reservoir outside of haloes, which is in fact larger in denser regions. The non-halo component may therefore be partially composed of truly diffuse dark matter particles that are dynamically hotter due to tidal stripping and are accreted at a suppressed rate in denser regions. We also discuss the implications of these results for how to modify the analytic extended Press-Schechter model of halo growths, which in its original form does not predict environmental dependence.
An analysis of NP-completeness in novelty and diversity ranking

A useful ability for search engines is to be able to rank objects with novelty and diversity: the top k documents retrieved should cover possible intents of a query with some distribution, or should contain a diverse set of subtopics related to the user's information need, or contain nuggets of information with little redundancy. Evaluation measures have been introduced to measure the effectiveness of systems at this task, but these measures have worst-case NP-hard computation time. The primary consequence of this is that there is no ranking principle akin to the Probability Ranking Principle for document relevance that provides uniform instruction on how to rank documents for novelty and diversity. We use simulation to investigate the practical implications of this for optimization and evaluation of retrieval systems.
Quantifying Price Liberalization in Russia

Abstract We seek to quantify the success of Russia's attempt to achieve price-liberalization initiatives as part of the reforms established under the Big Bang of January 1992. We do so by studying the time-series behavior of commodity prices between 1992–1995 and focusing on the relationship between the behavior of prices of similar goods within and across cities. We supplement this analysis by examining city-level surveys that seek to quantify the extent to which firms are currently able to set and adjust commodity prices in accordance with market conditions. Our evidence suggests that price liberalization gradually gained momentum following the Big Bang and that prices generally reflected market conditions by the first quarter of 1995. However, regional pockets of resistance to price-reform efforts continue to persist, indicating that Russia has yet to achieve full market integration. J. Comp. Econom., December 1998, 26(4), pp. 735–760. University of Pittsburgh, Pittsburgh, Pennsylvania 15260.
Biomimetic polyene cyclizations.

Certain polyenic substances having trans olefinic bonds in a 1,5 relationship can be induced to undergo stereospecific, non-enzymic, cationic cyclization to give polycyclic products with all-trans (“natural”) configuration. These transformations appear to mimic in principle the biogenetic conversion of squalene into polycyclic triterpenoids. Acetal and allylic alcohol functions are effective initiators for these cyclizations, and methylacetylenic end groups are particularly useful terminators since they lead to five-membered rings. Thus a tetraenic acetal having no chiral centers has been converted in a single step into a tetracyclic product having seven such centers. The process is highly stereoselective, giving only two of 64 possible racemates. Systems have also been developed for effecting the total synthesis of the steroid nucleus in a single step starting from a substrate containing only one ring. The mechanism of these biomimetic cyclizations and also that of their enzymic counterparts is still unknown, but the balance of the evidence favors a synchronous process.
Attitudes and cognitive organization.

(1946). Attitudes and Cognitive Organization. The Journal of Psychology: Vol. 21, No. 1, pp. 107-112.
Enantioselective Thiourea-Catalyzed Additions to Oxocarbenium Ions

Asymmetric, catalytic reactions of oxocarbenium ions are reported. Simple, chiral urea and thiourea derivatives are shown to catalyze the enantioselective substitution of silyl ketene acetals onto 1-chloroisochromans. A mechanism involving anion binding by the chiral catalyst to generate a reactive oxocarbenium ion is invoked. Catalysts bearing tertiary benzylic amide groups afforded highest enantioselectivities, with the optimal structure being derived from enantioenriched 2-arylpyrrolidine derivatives.
Parametric Deflection Approximations for End-Loaded, Large-Deflection Beams in Compliant Mechanisms

Geometric nonlinearities often complicate the analysis of systems containing largedeflection members. The time and resources required to develop closed-form or numerical solutions have inspired the development of a simple method of approximating the deflection path of end-loaded, large-deflection cantilever beams. The path coordinates are parameterized in a single parameter called the pseudo-rigid-body angle. The approximations are accurate to within 0.5 percent of the closedform elliptic integral solutions. A physical model is associated with the method, and may be used to simplify complex problems. The method proves to be particularly useful in the analysis and design of compliant mechanisms
Understanding Trend and Cycle in Asset Values: Reevaluating the Wealth Effect on Consumption

Both textbook economics and common sense teach us that the value of household wealth should be related to consumer spending. At the same time, movements in asset values often seem disassociated with important movements in consumer spending, as episodes such as the 1987 stock market crash and the contraction in equity values that occurred in the fall of 1998 suggest. An important first step in understanding the consumption-wealth linkage is determining how closely the two variables are actually correlated, and whether there exist important movements in asset values that are not associated with changes in consumption. This paper provides evidence that a surprisingly small fraction of the variation in household net worth is related to variation in aggregate consumer spending. We use empirical techniques that allow us to quantify the relative importance of permanent and transitory innovations in the variation of consumer spending and wealth and find that transitory shocks dominate post-war variation in wealth, while permanent shocks dominate variation in aggregate consumption. Although transitory innovations are found to have little influence on consumer spending, they have long-lasting effects on wealth , exhibiting a half-life of a little over two years. The findings suggest that most macro models which make no allowance for transitory variation in wealth that is orthogonal to consumption are likely to misstate both the timing and magnitude of the consumption-wealth linkage.(This abstract was borrowed from another version of this item.)
Two theorems about maximal Cohen-Macaulay modules

This paper contains two theorems concerning the theory of maximal Cohen-Macaulay modules. The first theorem proves that certain Ext groups between maximal Cohen-Macaulay modules M and N must have finite length, provided only finitely many isomorphism classes of maximal Cohen-Macaulay modules exist having ranks up to the sum of the ranks of M and N. This has several corollaries. In particular it proves that a Cohen-Macaulay local ring of finite Cohen-Macaulay type has an isolated singularity. A well-known theorem of Auslander gives the same conclusion but requires that the ring be Henselian. Other corollaries of our result include statements concerning when a ring is Gorenstein or a complete intersection on the punctured spectrum, and the recent theorem of Leuschke and Wiegand that the completion of an excellent Cohen-Macaulay local ring of finite Cohen-Macaulay type is again of finite Cohen-Macaulay type. The second theorem proves that a complete local Gorenstein domain of positive characteristic p and dimension d is F-rational if and only if the number of copies of R splitting out of R 1/p e divided by p de has a positive limit. This result generalizes work of Smith and Van den Bergh. We call this limit the F-signature of the ring and give some of its properties.
Performance measure for improving irrigation management

A measure to evaluate performance in irrigation systems is analyzed using the mean square prediction error concept. In the context of irrigation system management, the term error means the deviation of actual performance from a reference performance. The measure assesses performance in terms of the management objectives of adequacy and dependability of water delivery and an equitable distribution among various water users. It provides an understanding of the management capacity to schedule and distribute water in an irrigation system. Application of the performance measure is demonstrated by evaluating performance of an irrigation system in the Northwest Frontier Province of Pakistan.
The Taliban and Islam

This paper examines the aims, motives and methods of the Taliban, the present rulers of most of Afghanistan. In accordance with their fundamentalist views the Taliban have established an Islamic system which focuses on the implementation of Shariah. This paper argues that the Taliban apply directly the divine injunctions which they have drastically sharpened ‐ that means without being sanctioned by act of law of men. The government which the Taliban have set up has so far reached only a low level of institutionalization; the real power emanates from their leader, Mullah Omar.
Enantioselective O- and N-nitroso aldol synthesis of tin enolates. Isolation of three BINAP-silver complexes and their role in regio- and enantioselectivity.

The selective generation of three different silver−BINAP catalysts has been achieved via the proper combination of metal/ligand ratio and/or choice of silver salt. Indeed, the X-ray crystallographic study has been used to gain insight into the structure of the catalyst. After the evaluation of each species, 1:1 (AgX·(R)-BINAP) complex was found to be the real active species in the O-selective nitroso aldol reaction. On the other hand, a systematic survey of solvent has shown that the optimal 2:1 (AgX·(R)-BINAP) complex is the effective catalyst in the N-selective pathway. Thus, a new method of generation of the silver−BINAP catalyst and the synthetic transformations provide not only new insights into the developing area of catalytic enantioselective nitroso aldol synthesis but also clear guidance for the design of an effective catalyst.