cssi/SciSciGPT-SciSciNet huggingface dataset:
Near-field radiation between graphene-covered carbon nanotube arrays

It has been shown that at small separation distances, thermal radiation between hyperbolic metamaterials is enhanced over blackbodies. This theoretical study considers near-field radiation when graphene is covered on the surfaces of two semi-infinite vertically aligned carbon nanotube (VACNT) arrays separated by a sub-micron vacuum gap. Doped graphene is found to improve photon tunneling in a broad hyperbolic frequency range, due to the interaction with graphene-graphene surface plasmon polaritons (SPP). In order to elucidate the SPP resonance between graphene on hyperbolic substrates, vacuum-suspended graphene sheets separated by similar gap distances are compared. Increasing the Fermi energy through doping shifts the spectral heat flux peak toward higher frequencies. Although the presence of graphene on VACNT does not offer huge near-field heat flux enhancement over uncovered VACNT, this study identifies conditions (i.e., gap distance and doping level) that best utilize graphene to augment near-field radiation. Through the investigation of spatial Poynting vectors, heavily doped graphene is found to increase penetration depths in hyperbolic modes and the result is sensitive to the frequency regime. This study may have an impact on designing carbon-based vacuum thermophotovoltaics and thermal switches.
Theoretical Spectral Models of T Dwarfs at Short Wavelengths and Their Comparison with Data

We have generated new, self-consistent spectral and atmosphere models for the effective temperature range 600-1300 K thought to encompass the known T dwarfs. For the first time, theoretical models are compared with a family of measured T dwarf spectra at wavelengths shortward of ~1.0 μm. By defining spectral indices and standard colors in the optical and very near-infrared, we explore the theoretical systematics with Teff, gravity, and metallicity. We conclude that the short-wavelength range is rich in diagnostics that complement those in the near-infrared now used for spectral subtyping. We also conclude that the wings of the Na D and K I (7700 A) resonance lines and aggressive rainout of heavy metals (with the resulting enhancement of the sodium and potassium abundances at altitude) are required to fit the new data shortward of 1.0 μm. Furthermore, we find that the water bands weaken with increasing gravity, that modest decreases in metallicity enhance the effect in the optical of the sodium and potassium lines, and that at low values of Teff, in a reversal of the normal pattern, optical spectra become bluer with further decreases in Teff. Moreover, we conclude that T dwarf subtype is not a function of Teff alone but that it is a nontrivial function of gravity and metallicity as well. As do Marley and coworkers in their 2002 work, we see evidence in early T dwarf atmospheres of a residual effect of clouds. With cloudless models, we obtain spectral fits to the two late T dwarfs with known parallaxes, but a residual effect of clouds on the emergent spectra of even late T dwarfs cannot yet be discounted. However, our focus is not on detailed fits to individual objects but on the interpretation of the overall spectral and color trends of the entire class of T dwarfs, as seen at shorter wavelengths.
Unified all-pairs shortest path algorithms in the chordal hierarchy

Abstract The objective of this paper is to advance the view that solving the all-pairs shortest path (APSP) problem for a chordal graph G is a two-step process: the first step is determining vertex pairs at distance two (i.e., computing G 2 ) and the second step is finding the vertex pairs at distance three or more. The main technical result here is that the APSP problem for a chordal graph can be solved in O ( n 2 ) time (optimally), if G 2 is already known. It can be shown that computing G 2 for chordal graphs is as hard as for general graphs. We then show certain subclasses of chordal graphs for which G 2 can be computed more efficiently. This leads to optimal APSP algorithms for these classes of graphs in a more natural way than previously known results. Finally, we present an optimal parallel algorithm for the APSP problem on chordal graphs by exploiting new structural properties of shortest paths. Our parallel algorithm uses O ( M ( n )) operations where M ( n ) is the time needed for the fastest known algorithm for multiplying two n × n matrices over a ring.
Microwave and laser spectroscopy of carbon chains and rings

The interstellar gas and the gas ejected into space by cool stars are now known to contain a rich collection of molecules. Most of these are organic compounds, some of which are familiar to the terrestrial chemist and can be found in a standard chemical stockroom, but many are entirely new molecules which have been detected and identified in space for the first time. Most of the nearly 100 polyatomic molecules so far detected in astronomical sources by radio telescopes are highly unsaturated carbon chains, a structure which is explosively unstable at even moderate density, and therefore difficult to study spectroscopically on Earth. For this reason laboratory detection has until quite recently lagged well behind the astronomical discovery of many carbon chains. The application of Fourier transform microwave and laser cavity ringdown absorption spectroscopy to supersonic molecular beams has largely overcome this difficulty, yielding in this laboratory during the past four years more than 75 new reactive molecules, including long carbon chains, chains attached to rings, silicon–carbon rings, and several protonated molecular ions. All or nearly all of these are candidates for astronomical discovery because they are highly polar and are close in structure and composition to molecules which have already been discovered in space. Seven have already been found with large radio telescopes, six as a result of the laboratory work described here. These discoveries include the largest interstellar molecule HC11N, the largest ring, SiC3, and the largest positive ion, HC3NH+. One of our most interesting recent laboratory discoveries is the laser detection of a strong molecular band at λ4429, the wavelength of the strongest and best known diffuse interstellar band.
A comparison of Dodgson's method and Kemeny's rule

In an election without a Condorcet winner, Dodgson's method is designed to find the candidate that is “closest” to being a Condorcet winner. Similarly, if the head-to-head elections among all candidates do not give a complete transitive ranking, then Kemeny's Rule finds the “closest” transitive ranking. This paper uses geometric techniques to compare Dodgson's and Kemeny's notions of closeness and explain how conflict can arise between the two methods.
A Model-independent Lower Limit on the Number of Gamma-Ray Burst Hosts from Repeater Statistics

We present a general statistical analysis of gamma-ray bursts embedded in a host population. If no host generates more than one observed burst, then we show that there is a model-independent lower bound on the number of hosts, H, of the form H>cB2, where B is the number of observed bursts and c is a constant of order 1 that depends on the confidence level (CL) attached to the bound. A recent analysis by Tegmark et al. shows that the BATSE 3B catalog of 1122 bursts is consistent with no repeaters being present, and, assuming that this is indeed the case, our result implies a host population with at least H=1.2×106 members. Without the explicit assumption of no repeaters, a Bayesian analysis based on the results of Tegmark et al. can be performed that gives the weaker bound of H>1.7×105 at the 90% CL. In the light of the nondetection of identifiable hosts in the small error boxes associated with transient counterparts to GRBs, this result gives a model-independent lower bound to the number of any rare or exotic hosts. If, in fact, GRBs are found to be associated with a particular subclass of galaxies, then an analysis like that presented here can be used to place a lower bound on the fraction of galaxies in this subclass. Another possibility is to treat galaxy clusters (rather than individual galaxies) as the host population, provided that the angular size of each cluster considered is less than the resolution of the detector. Finally, if repeaters are ever detected in a statistically significant manner, this analysis can be readily adapted to find upper and lower limits on H.
Many-body wave scattering by small bodies

Scattering problem by several bodies, small in comparison with the wavelength, is reduced to linear algebraic systems of equations, in contrast to the usual reduction to some integral equations.
Look-Ahead Routing and Message Scheduling in Delay-Tolerant Networks

Routing is one of the most challenging development issues in Delay-Tolerant Networks (DTNs) because of lack of continuous connection. Existing routing schemes for DTNs provide best effort service, but are unable to optimize QoS and support message priority. In this paper, we present a Look-Ahead Routing and Message Scheduling approach (ALARMS) which exploits more accurate knowledge about various parameters regarding routing to achieve better QoS in the DTN. We assume a variation of the well-known ferry model, in which there are ferry nodes moving along pre-defined routes to exchange messages with the gateway node of each region on the route and also pass to the gateway nodes look-ahead routing information about when it will arrive at each gateway node on the route in the next two rounds and how long it will stay. The gateway nodes use this information to estimate the delivery delay of each message when being delivered by different ferries, and schedule the message to be delivered by the ferry which arrives earliest at the destination. Simulation results show that ALARMS outperforms three existing routing protocols: epidemic routing, Spray-and-Wait, and Spray-and-Focus, in terms of delay time, delivery ratio, and overhead. We also discuss five enhancement strategies on ALARMS and how ALARMS can support message prioritization.
Ethanol and nicotine interaction within the posterior ventral tegmental area in male and female alcohol-preferring rats: evidence of synergy and differential gene activation in the nucleus accumbens shell.

Rationale Ethanol and nicotine are frequently co-abused. The biological basis for the high co-morbidity rate is not known. Alcohol-preferring (P) rats will self-administer EtOH or nicotine directly into the posterior ventral tegmental area (pVTA).
Simulation of radiation from lightning return strokes - The effects of tortuosity

A Monte Carlo simulation has been developed for the electromagnetic fields radiated from a tortuous lightning channel. This was done using a piecewise linear model for the channel and employing for each element the field radiated by a traveling wave on an arbitrarily oriented filament over a conducting plane. The simulation reproduces experimental data reasonably well and has been used to study the effects of tortuosity on the fields radiated by return strokes. Tortuosity can significantly modify the radiated waveform, tending to render it less representative of the current pulse and more nearly unipolar than one would expect based on the theory for a long straight channel. In the frequency domain the effect of tortuosity is an increase in high frequency energy as compared with an equivalent straight channel. The extent of this increase depends on the mean length of the elements comprising the channel and can be significant.
Light hadron weak matrix elements

Abstract Recent developments in lattice QCD calculation of weak matrix elements involving light quarks are described. We focus on four topics: BK with the Kogut-Susskind and Wilson quark actions, ΔI = 1 2 rule, proton decay matrix elements and the application of domain wall QCD to calculation of weak matrix elements.
A Sampling-Based Approach for Probabilistic Design with Random Fields

An original technique to incorporate random fields non-intrusively in probabilistic design is presented. The approach is based on the extraction of the main features of a random field using a limited number of experimental observations (snapshots). An approximation of the random field is obtained using proper orthogonal decomposition (POD). For a given failure criterion, an explicit limit state function (LSF) in terms of the coefficients of the POD expansion is obtained using a support vector machine (SVM). An adaptive sampling technique is used to generate samples and update the approximated LSF. The coefficients of the orthogonal decomposition are considered as random variables with distributions determined from the snapshots. Based on these distributions and the explicit LSF, the approach allows for an efficient assessment of the probabilities of failure. In addition, the construction of explicit LSF has the advantage of handling discontinuous responses. Two test-problems are used to demonstrate the proposed methodology used for the calculation of probabilities of failure. The first example involves the linear buckling of an arch structure for which the thickness is a random field. The second problem concerns the impact of a tube on a rigid wall. The planarity of the walls of the tube is considered as a random field.
Anthropological Approaches to Information Systems and Behavior

L'application d'approches anthropologiques a l'etude des systemes et des comportements d'information peut veritablement humaniser la technologie et la recherche en ce domaine. L'A. considere la culture commme un systeme d'information. Elle presente les avantage et les limitations des methodes ethnographiques empiriques, en portant une attention particuliere a la distinction entre les statuts -emique ou -etique des donnees. Elle souligne l'importance des comparaisons culturelles et temporelles pour la recherche en sciences de l'information et la necessite d'integrer des facteurs materiels dans les analyses. Ces methodes permettent de conduire une strategie de recherche dite theorie de fouille optimale.
Chandra Observations of the Young Pulsar PSR B0540–69

The young pulsar PSR B0540-69 was one of the first targets observed with the Chandra X-Ray Observatory. The high angular resolution of Chandra allows us to resolve the compact nebula surrounding the pulsar. We have determined a position for PSR B0540-69 of R.A. = 05h40m11221,decl. = -69°19'5498 (J2000) with a 1 σ radial uncertainty of 07. Combining our measurements of the pulsar period with previous measurements covering a span of 12 years, we derive a braking index of 2.082 ± 0.005 (95% confidence). The spectrum of the pulsed emission is consistent with a power law with a photon index of 1.83 ± 0.13. The compact nebula has a softer spectrum with a photon index of 1.85-2.26.
Reconciling neutrino flux from heavy dark matter decay and recent events at IceCube

The IceCube detector has recently reported the observation of 28 events at previously unexplored energies. While the statistics of the observed events are still low, these events hint at the existence of a neutrino flux over and above the atmospheric neutrino background. We investigate the possibility that a significant component of the additional neutrino flux originates due to the decay of a very heavy dark matter (VHDM) particle via several possible channels into standard model particles. We show that a combination of a power law astrophysical neutrino spectrum and the neutrino flux from the decay of a DM species of mass in the range 150 − 400 TeV improves the fit to the observed neutrino events than that obtained from a best-fit astrophysical flux alone. Assuming the existence of an astrophysical background described by the IC best-fit, we also show that, for the decay of even heavier DM particles (m DM ~ 1 PeV), the same observations impose significant constraints on the decay lifetimes. Allowing the astrophysical flux normalization to vary leads to modifications of these limits, however, there is still a range of dark matter mass and lifetime that is excluded by the IC results.
Phases of R-charged black holes, spinning branes and strongly coupled gauge theories

We study the thermodynamic stability of charged black holes in gauged supergravity theories in D = 5, D = 4 and D = 7. We find explicitly the location of the Hawking-Page phase transition between charged black holes and the pure anti-de Sitter space-time, both in the grand-canonical ensemble, where electric potentials are held fixed, and in the canonical ensemble, where total charges are held fixed. We also find the explicit local thermodynamic stability constraints for black holes with one non-zero charge. In the grand-canonical ensemble, there is in general a region of phase space where neither the anti-de Sitter space-time is dynamically preferred, nor are the charged black holes thermodynamically stable. But in the canonical ensemble, anti-de Sitter space-time is always dynamically preferred in the domain where black holes are unstable. We demonstrate the equivalence of large R-charged black holes in D = 5, D = 4 and D = 7 with spinning near-extreme D3-, M2- and M5-branes, respectively. The mass, the charges and the entropy of such black holes can be mapped into the energy above extremality, the angular momenta and the entropy of the corresponding branes. We also note a peculiar numerological sense in which the grand-canonical stability constraints for large charge black holes in D = 4 and D = 7 are dual, and in which the D = 5 constraints are self-dual.
A Remarkable Synthesis of the Bicyclo[4.2.1]Nonenedione System

Abstract Allylation of the C-2 enolate of the bicyclo[3.3.1]nonenedione 1 proceeds with an unusual acyl migration to yield the C-allyl ester 5 of the rearranged bicyclo[4.2.1]nonenedione system.
Synthesis of allylic ketones via acylation of allylic mercurials

Abstract Allylic mercurials, readily available from allylic halides and mercury(O), react with acyl chlorides and AlCl 3 under mild reaction conditions to afford high yields of allylic ketones.
Statistical estimation of service cracks and maintenance cost for aircraft structures

A method is developed for the statistical estimation of the number of cracks to be repaired in service as well as the repair and the maintenance costs. The present approach accounts for the statistical distribution of the initial crack size, the statistical nature of the NDI technique used for detecting the crack, and the renewal process for the crack propagation of repaired cracks. The mean and the standard deviation of the cumulative number of cracks to be repaired are computed as a function of service time. The statistics of the costs of repair and maintenance, expressed in terms of the percentage of the cost of replacement, are estimated as a function of service time. The results of the present study provide relevant information for the decision of fleet management, the estimation of life cycle cost, and procurement specifications. The present study is essential to the design and cost optimization of aircraft structures.
Incidences between Points and Circles in Three and Higher Dimensions

We show that the number of incidences between m distinct points and n distinct circles in ℝd, for any d ≥ 3, is O(m6/11n9/11κ(m3/n)+m2/3n2/3+m+n), where κ(n)=(log n)O(α(n))2 and where α(n) is the inverse Ackermann function. The bound coincides with the recent bound of Aronov and Sharir, or rather with its slight improvement by Agarwal et al., for the planar case. We also show that the number of incidences between m points and n unrestricted convex (or bounded-degree algebraic) plane curves, no two in a common plane, is O(m4/7n17/21+m2/3n2/3+m+n), in any dimension d ≥ 3. Our results improve the upper bound on the number of congruent copies of a fixed tetrahedron in a set of n points in 4-space and the lower bound for the number of distinct distances in a set of n points in 3-space. Another application is an improved bound for the number of incidences (or, rather, containments) between lines and reguli in three dimensions. The latter result has already been applied by Feldman and Sharir to obtain a new bound on the number of joints in an arrangement of lines in three dimensions.
Galactic Populations of Radio and Gamma-Ray Pulsars in the Polar Cap Model

We simulate the characteristics of the Galactic population of radio and γ-ray pulsars using Monte Carlo techniques. At birth, neutron stars are spatially distributed in the Galactic disk, with supernova-kick velocities, and randomly dispersed in age back to 109 yr. They are evolved in the Galactic gravitational potential to the present time. From a radio luminosity model, the radio flux is filtered through a selected set of radio-survey parameters. γ-ray luminosities are assigned using the features of recent polar cap acceleration models invoking space-charge-limited flow, and a pulsar death valley further attenuates the population of radio-loud pulsars. Assuming a simple emission geometry with aligned radio and γ-ray beams of 1 sr solid angle, our model predicts that EGRET should have seen seven radio-loud and one radio-quiet γ-ray pulsars. With much improved sensitivity, GLAST, on the other hand, is expected to observe 76 radio-loud and 74 radio-quiet γ-ray pulsars, of which seven would be identified as pulsed sources. We also explore the effect of magnetic field decay on the characteristics of the radio and γ-ray pulsar populations. Including magnetic field decay on a timescale of 5 Myr improves agreement with the radio pulsar population and increases the predicted number of GLAST-detected pulsars to 90 radio-loud and 101 radio-quiet (nine pulsed) γ-ray pulsars. The lower flux threshold allows GLAST to detect γ-ray pulsars at larger distances than those observed by the radio surveys used in this study.
Solution to the King's Problem in Prime Power Dimensions

It is shown how to ascertain the values of a complete set of mutually complementary observables of a prime power degree of freedom by generalizing the solution in prime dimensions given by Englert and Aharonov [Phys. Lett. A284, 1 -5 (2001)].
Carbon dioxide gas accelerates solventless synthesis

Some solventless reactions involving solid reactants or products can be accelerated by the influence of subcritical gaseous CO2.
Polynomially bounded cohomology and discrete groups

Abstract We establish the homological foundations for studying polynomially bounded group cohomology, and show that the natural map from PH * ( G ; Q ) to H * ( G ; Q ) is an isomorphism for a certain class of groups.
Giant Optical Pulsations from Ruby

Giant pulses of optical maser radiation have been produced which are several orders of magnitude larger than the commonly observed spontaneous pulses. The pulses were produced by varying the effective reflectivity of the reflecting surfaces at the ends of the ruby rod through a Kerr-cell switching technique. The measured pulse characteristics are found to be in agreement with theoretical predictions.
SUPER-KEPLERIAN FREQUENCIES IN ACCRETION DISKS. IMPLICATIONS FOR MASS AND SPIN MEASUREMENTS OF COMPACT OBJECTS FROM X-RAY VARIABILITY STUDIES

The detection of fast quasi-periodic variability from accreting black holes and neutron stars has been used to constrain their masses, radii, and spins. If the observed oscillations are linear modes in the accretion disks, then bounds can be placed on the properties of the central objects by assuming that these modes are locally sub-Keplerian. If, on the other hand, the observed oscillations correspond to nonlinear resonances between disk modes, then the properties of the central objects can be measured by assuming that the resonant modes are excited at the same radial annulus in the disk. In this paper, we use numerical simulations of vertically integrated, axisymmetric hydrodynamic accretion disks to provide examples of situations in which the assumptions implicit in both methods are not satisfied. We then discuss our results for the robustness of the mass and spin measurements of compact objects from variability studies.
Monodisperse FePt Nanoparticles and Ferromagnetic FePt Nanocrystal Superlattices

Synthesis of monodisperse iron-platinum (FePt) nanoparticles by reduction of platinum acetylacetonate and decomposition of iron pentacarbonyl in the presence of oleic acid and oleyl amine stabilizers is reported. The FePt particle composition is readily controlled, and the size is tunable from 3- to 10-nanometer diameter with a standard deviation of less than 5%. These nanoparticles self-assemble into three-dimensional superlattices. Thermal annealing converts the internal particle structure from a chemically disordered face-centered cubic phase to the chemically ordered face-centered tetragonal phase and transforms the nanoparticle superlattices into ferromagnetic nanocrystal assemblies. These assemblies are chemically and mechanically robust and can support high-density magnetization reversal transitions.
A simplified Kalman estimator for an aircraft landing display.

Kalman filter simulation for estimating aircraft position and velocity from airborne digital computer data in zero-zero landing system
Generation of anionic intermediates by intramolecular nucleophilic attack at silicon

Abstract Benzyl and allyl anion equivalents can be generated from benzyl- and allylsilanes by intramolecular alkoxide attack.
PLANETARY CHAOTIC ZONE CLEARING: DESTINATIONS AND TIMESCALES

We investigate the orbital evolution of particles in a planet's chaotic zone to determine their final destinations and their timescales of clearing. There are four possible final states of chaotic particles: collision with the planet, collision with the star, escape, or bounded but non-collision orbits. In our investigations, within the framework of the planar circular restricted three body problem for planet-star mass ratio μ in the range 10–9 to 10–1.5, we find no particles hitting the star. The relative frequencies of escape and collision with the planet are not scale-free, as they depend upon the size of the planet. For planet radius Rp ≥ 0.001 RH where RH is the planet's Hill radius, we find that most chaotic zone particles collide with the planet for μ 10–5; particle scattering to large distances is significant only for higher mass planets. For fixed ratio Rp /RH , the particle clearing timescale, T cl, has a broken power-law dependence on μ. A shallower power law, T cl ~ μ–1/3, prevails at small μ where particles are cleared primarily by collisions with the planet; a steeper power law, T cl ~ μ–3/2, prevails at larger μ where scattering dominates the particle loss. In the limit of vanishing planet radius, we find T cl ≈ 0.024 μ–3/2. The interior and exterior boundaries of the annular zone in which chaotic particles are cleared are increasingly asymmetric about the planet's orbit for larger planet masses; the inner boundary coincides well with the classical first order resonance overlap zone, Δa cl, int 1.2 μ0.28 ap ; the outer boundary is better described by Δa cl, ext 1.7 μ0.31 ap , where ap is the planet-star separation.
Supersymmetric domain wall world from D=5 simple gauged supergravity

Abstract We address a supersymmetric embedding of domain walls with asymptotically anti-deSitter (AdS) space-times in five-dimensional simple, N =2 U(1) gauged supergravity theory constructed by Gunaydin, Townsend and Sierra. These conformally flat solutions interpolate between supersymmetric AdS vacua, satisfy the Killing spinor (first order) differential equations, and the four-dimensional world on the domain wall is a flat world with N =1 supersymmetry. Regular solutions in this class have the energy density related to the cosmological constants of the supersymmetric AdS vacua. An analysis of such solutions is given for the example of one (real, neutral) vector supermultiplet with the most general form of the prepotential. There are at most two supersymmetric AdS vacua that are in general separated by a singularity in the potential. Nevertheless the supersymmetric domain wall solution exists with the scalar field interpolating continuously across the singular region.
Modeling datalog fact assertion and retraction in linear logic

Practical algorithms have been proposed to efficiently recompute the logical consequences of a Datalog program after a new fact has been asserted or retracted. This is essential in a dynamic setting where facts are frequently added and removed. Yet while assertion is logically well understood as incremental inference, the monotonic nature of first-order logic is ill-suited to model retraction. As such, the traditional logical interpretation of Datalog offers at most an abstract specification of Datalog systems, but has tenuous relations to the algorithms that perform efficient assertions and retractions in practical implementations. This paper proposes a logical interpretation of Datalog based on linear logic. It not only captures the meaning of Datalog updates, but also provides an operational model that underlies the dynamic changes of the set of inferable facts, all within the confines of logic. We prove the correctness of this interpretation with respect to its traditional counterpart.
Estrogen replacement therapy and the risk of venous thrombosis

Abstract purpose: Estrogen replacement therapy is believed by many physicians to cause thrombophlebitis and to be contraindicated in women at risk for this disease. However, clinical data supporting this assumption are scant, and further investigation is required. patients and methods: We tested the estrogen-thrombophlebitis association in a case-control study. Charts of all consecutive women aged 45 years or older with a primary or secondary discharge diagnosis of thrombophlebitis, venous thrombosis, or pulmonary embolism were reviewed; 121 cases and 236 controls matched for age, year of admission, admitting service, and socioeconomic status were obtained. Hormone use and nonuse were validated in a subset of randomly selected women. results: Cases and controls, whose average age was 65 years, did not differ significantly on matching variables or on current use of exogenous estrogen (5.1% of cases versus 6.3% of controls). Other analyses that variously excluded women with a past history of thrombosis, women less than 50 years of age, women with thrombosis occurring after admission, and women whose estrogen use was indeterminate also did not support an increased risk of thrombotic disease. Adjustment for the presence of independent thrombotic risk factors did not alter the odds ratio for estrogen use. conclusion: This case-control study of older women, unselected for other thrombotic risk factors, does not support the commonly held assumption that replacement estrogen increases the risk of venous thrombosis.
Proper Referencing of Prior Art

In September 1999, this author published an editorial (ibid., vol. 46, no. 9, p. 1817, Sep. 1999) in IEEE Transactions on Electron Devices (T-ED) emphasizing the need for authors to pay special attention while referencing previously published related information. As mentioned at that time, omitting related work is not only unfair to researcher(s) who have made earlier contributions to the field but it also gives a distorted view of the topic to the reader. More importantly, it demonstrates an author??s lack of knowledge of prior art in their area of research. Hence, there may be significant room for improvement in the technical quality of the manuscript. Since then, we have continually sensitized the authors to this important issue before adopting the following measures. Every year, the Electron Devices Society (EDS) confers its prestigious Paul Rappaport and the more recent George Smith (2002) Awards for best papers published in our flagship publications IEEE T-ED and IEEE Electron Device Letters (EDL), respectively. To reward proper citation philosophy in EDS publications, we have now instituted clear guidelines to take this factor into account in the paper selection process for these awards. Also, we have tightened up the manuscript review process for both T-ED and EDL to make incomplete citations as grounds for rejection.
ST Elevation during Exercise Testing

The interpretation of exercise-induced ST elevation should differ according to the resting electrocardiogram. When it appears over or adjacent to diagnostic Q waves, it is usually asociated with a ventricular aneurysm or exercise-induced wall motion abnormality
De la desesperanza a la plenitud: la revelación epifánica en la poesía de Álvaro Mutis

The boundaries between prose and verse, the presence of different voices´s characters, wich act as semi-heteronyms and gravitate the texts giving distance to the poetic self; the journey to the past as a revealing experience and the insuffiency of word as the mean of expression are the principal subjects of the Alvaro Mutis´s poetry. In this essay, the concept of epiphany, understood as a representation of the perfect order or as an indecipherable formula of a mystery against the agonistic circumstances of disaster, unifies the colombian’s poetic work.
Continuing postgraduate medical education in geriatrics.

: At present the medical student's education in geriatrics is left chiefly to the postgraduate period. There are encouraging signs, however, that medical students are being made more aware of the relationship of aging and chronic disease to the understanding of medicine in general. In the postgraduate period, when physicians are supposed to keep up to date by means of continuing education, there are very few opportunities in the field of geriatrics. Moreover, such programs often are not properly coordinated and monitored. Attempts are being made to rectify this situation. Single individuals or professional societies are weak alone, but can be strong when united in establishing training programs in geriatrics. The American Geriatrics Society and the Gerontological Society should be in the forefront. They should either develop a specific program of their own or should cooperate with the American Academy of General Practice and the American Medical Association in formulating courses that include geriatrics. These programs would undoubtedly lead to institutional postdoctoral education in the subject, and eventually would involve medical students. Meanwhile, all such efforts would improve the care of the aged and infirm.
Trends and transitions in the institutional environment for public and private science

The last quarter-century bore witness to a sea change in academic involvement with commerce. Widespread university-based efforts to identify, manage, and market intellectual property (IP) have accompanied broad shifts in the relationship between academic and proprietary approaches to the dissemination and use of science and engineering research. Such transformations are indicators of institutional changes at work in the environment faced by universities. This paper draws upon a fifteen-year panel (1981–1995) of university-level data for 87 research-intensive US campuses in order to document trends and transitions in relationships among multiple indicators of academic and commercial engagement. The institutional environment for public and private science is volatile, shifting in fits and starts from a situation conducive to organizational learning through high volume patenting to a more challenging arrangement that links indiscriminate pursuit of IP with declines in both the volume and impact of academic science. The pattern and timing of these transitions may support an enduring system of stratification that offers increasing returns to first-movers while limiting the opportunities available to universities that are later entrants to the commercial realm. Unpacking the systematic effects of university research commercialization requires focused attention on the sources and trajectories of profound institutional change.
Comparison of left ventriculography and coronary arteriography with positron emission tomography in assessment of myocardial viability.

Background: Assessment of viability of myocardium after an ischemic insult is an important clinical question that affects decisions pertaining to potential revascularization. The results of contrast left ventriculograms and coronary angiography were compared to positron emission tomography (PET) in 64 patients with coronary artery disease and reduced left ventricular function. Hypothesis: The study was undertaken to determine the relative utility of the invasive studies in the assessment of viability. Methods: Right anterior oblique ventriculograms were assessed for hypokinesis, akinesis, or dyskinesis in six segments. The PET scans were assessed for viability by visual estimation of flourodeoxyglucose (FDG) uptake in six segments that corresponded to the segments analyzed on the ventriculograms. Results: Of a total of 373 segments successfully analyzed by PET, 272 were judged to be viable (normal or hypokinetic) by contrast ventriculography. Of these, 253 (93%) were considered viable by PET. Of 177 segments deemed either normal or mild-to-moderately hypokinetic by ventriculography, 170 (94%) were viable by PET. Of 95 severely hypokinetic segments, 83 (84%) were viable by PET. Of 79 akinetic segments, 44 (56%) were considered viable by PET. For segments that were dyskinetic and thought to be nonviable by ventriculography, 19 of 22 (86%) were also considered nonviable by PET. For 294 segments for which a determination on viability was made based on the presence of wall motion on the ventriculogram (normal, hypokinetic, or dyskinetic; not akinetic), there was excellent agreement with PET (93%; p < 0.001). In 49 patients there was akinesis in no more than one segment in either the anterior or inferior territories, indicating the potential for assessment of viability by ventriculography in at least two of three segments in each territory. Coronary anatomy was analyzed to assess whether coronary patency could help in assessing viability. Segments supplied by patent arteries were more likely to be viable by PET than segments supplied by occluded arteries (p < 0.001). Akinetic segments were more likely to be supplied by occluded arteries (56 vs. 23, 72%). Dyskinetic segments were predominantly nonviable by PET (86%) and were usually supplied by occluded arteries (77%). Conclusion: In patients in whom the assessment of viability is clinically relevant, the presence of systolic inward motion on the contrast left ventriculogram correlates well with segment viability by PET, while outward or dyskinetic movement correlates well with nonviability. Thus, the use of PET to assess viability in many patients may be unnecessary.
Chiral 2,2'-bipyridines, 1,10-phenanthrolines, and 2,2':6',2' '-terpyridines: syntheses and applications in asymmetric homogeneous catalysis.

Although chiral phosphines have enjoyed a longtime popularity in the design of enantioselective catalytic systems, there has been a recent renaissance in the use of nitrogen ligands for this same purpose.1 This renaissance partly arises from several distinct advantages presented by nitrogen-containing ligands. First, they can often be employed in catalytic processes where the use of phosphines may be incompatible with the reaction conditions. Second, many nitrogen ligands are now available in enantiomerically pure form. Third, ligands that bind through nitrogen are known to coordinate with a wide variety of metal ions, and considerable progress has been made in understanding the role which these ligands play in affecting catalytic processes.
Virasoro Algebra and Wreath Product Convolution

Abstract We present a group theoretic construction of the Virasoro algebra in the framework of wreath products. This can be regarded as a counterpart of a geometric construction of Lehn in the theory of Hubert schemes of points on a surface.
On estimates of biharmonic functions on Lipschitz and convex domains

Using Maz ’ya type integral identities with power weights, we obtain new boundary estimates for biharmonic functions on Lipschitz and convex domains in ℝn. Forn ≥ 8, combinedwitharesultin[18], these estimates lead to the solvability of the Lp Dirichlet problem for the biharmonic equation on Lipschitz domains for a new range of p. In the case of convex domains, the estimates allow us to show that the Lp Dirichlet problem is uniquely solvable for any 2 − e < p < ∞ and n ≥ 4.
Velocity gradients in the intracluster gas of the perseus cluster

We report the results of spatially resolved X-ray spectroscopy of eight different ASCA pointings distributed symmetrically around the center of the Perseus Cluster. The outer region of the intracluster gas is roughly isothermal, with temperature ~6-7 keV and metal abundance ~0.3 solar. Spectral analysis of the central pointing is consistent with the presence of a cooling flow and a central metal abundance gradient. A significant velocity gradient is found along an axis at a position angle of ~135°, which is ~45° discrepant with the major axis of the X-ray elongation. The radial velocity difference is found to be greater than 1000 km s-1 Mpc-1 at the 90% confidence level. Simultaneous fittings of GIS 2 and 3 indicate that the velocity gradient is significant at the 95% confidence level, and the F-test rules out constant velocities at the 99% level. Intrinsic short- and long-term variations of gain are unlikely (P < 0.03) to explain the velocity discrepancies.
Market Efficiency and Natural Selection in a Commodity Futures Market

While the literature usually justifies informational efficiency in the context of rationality, this article shows informational efficiency by applying the evolutionary idea of natural selection. In a dynamic futures market, speculators are assumed to merely act upon their predetermined trading types (buyer or seller), their predetermined fractions of wealth allocated for speculation, and their inherent abilities to predict the spot price, reflected in their distributions of prediction errors with respect to the spot price. This article shows that the proportion of time that the futures price equals the spot price converges to one with probability 1. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
Electroluminescence and Photocurrent Generation from Atomically Sharp WSe2/MoS2 Heterojunction p–n Diodes

The p-n diodes represent the most fundamental device building blocks for diverse optoelectronic functions, but are difficult to achieve in atomically thin transition metal dichalcogenides (TMDs) due to the challenges in selectively doping them into p- or n-type semiconductors. Here, we demonstrate that an atomically thin and sharp heterojunction p-n diode can be created by vertically stacking p-type monolayer tungsten diselenide (WSe2) and n-type few-layer molybdenum disulfide (MoS2). Electrical measurements of the vertically staked WSe2/MoS2 heterojunctions reveal excellent current rectification behavior with an ideality factor of 1.2. Photocurrent mapping shows rapid photoresponse over the entire overlapping region with a highest external quantum efficiency up to 12%. Electroluminescence studies show prominent band edge excitonic emission and strikingly enhanced hot-electron luminescence. A systematic investigation shows distinct layer-number dependent emission characteristics and reveals important insight about the origin of hot-electron luminescence and the nature of electron-orbital interaction in TMDs. We believe that these atomically thin heterojunction p-n diodes represent an interesting system for probing the fundamental electro-optical properties in TMDs and can open up a new pathway to novel optoelectronic devices such as atomically thin photodetectors, photovoltaics, as well as spin- and valley-polarized light emitting diodes, on-chip lasers.
MHD Propulsion by Absorption of Laser Radiation

The conceptual design for a laser-riding air-breathing single stage shuttle which would use magnetohydrodynamic (MHD) forces to accelerate the engine working fluid is introduced. A gigawatt powerlevel photon beam delivered from an orbital laser power station is focused by the shuttle craft onto internal engine working fluid to create, within an annular ionization chamber, a confined air plasma stationary wave. Free electrons are immediately pumped from the plasma and ejected into the external slipstream at the perimeter of the machine. The remaining positively charged working fluid is accelerated by gasdynamic expansion and the pinch-plasma effect, and discharged at a rear nozzle. The vehicle slipstream, now negatively charged and conducting, interacts with a concentric positively charged plasma core to provide quasi-steady flight propulsive forces in an externally-excited-field MHD accelerator. Continuous MHD engine electric currents in the near megampere range are attained through the use of: a) remote power ionization of engine working fluid, and b) electron beam space-charge neutralization techniques reported in recent literature on fusion research. A cursory examination of the required laser power, thrust, exhaust velocities, electric current, and working fluid electrical conductivity reveals operable engine parameters in an interesting range indicating that the system may be worthy of further examination.
Loop corrections to radiative breaking of electroweak symmetry in supersymmetry.

One-loop corrections to the radiative breaking of electroweak symmetry in supergravity unified models are analyzed. It is shown that in a physically interesting domain of parameter space there is a large cancellation among the contributions of the first two generations of squarks and the three generations of sleptons to the vacuum expectation value (VEV) equations. Partial cancellations in other sectors are also found. These cancellations reduce the effect of the one-loop contributions to the VEV equations.
The production of a highly polarized atomic cesium beam

Abstract We have produced a cesium beam of 1014 atoms s−1 with more than 98% of the atoms in a single spin state. The beam was polarized by optically pumping it with a single laser diode whose frequency was switched between the 6s(F = 4)−6p 3 2 (F = 5) rmand 6s(F = 3)−6p 3 2 (F = 4) transitions at 100 kHz. To do this, it was necessary to determine the frequency modulation characteristics of the laser. The same laser was used to simultaneously probe the atomic population distribution. We find this to be a remarkably simple and inexpensive way to produce a highly spin polarized beam.
Violation of Continuous-Variable Einstein-Podolsky-Rosen Steering with Discrete Measurements

In this Letter, we derive an entropic Einstein-Podolsky-Rosen (EPR) steering inequality for continuous-variable systems using only experimentally measured discrete probability distributions and details of the measurement apparatus. We use this inequality to witness EPR steering between the positions and momenta of photon pairs generated in spontaneous parametric down-conversion. We examine the asymmetry between parties in this inequality, and show that this asymmetry can be used to reduce the technical requirements of experimental setups intended to demonstrate the EPR paradox. Furthermore, we develop a more stringent steering inequality that is symmetric between parties, and use it to show that the down-converted photon pairs also exhibit symmetric EPR steering.
Short-hard gamma-ray bursts

Two types of gamma-ray bursts (GRBs) are observed: short-duration hard spectrum GRBs and long-duration soft spectrum GRBs. For many years long GRBs were the focus of intense research while the lack of observational data limited the study of short-hard GRBs (SHBs). In 2005 a breakthrough occurred following the first detections of SHB afterglows, longer wavelength emission that follows the burst of gamma-rays. Similarly to long GRBs, afterglow detections led to the identification of SHB host galaxies and measurement of their redshifts. These observations established that SHBs are cosmological relativistic sources that, unlike long GRBs, do not originate from the collapse of massive stars, and therefore constitute a distinct physical phenomenon. One viable model for SHB origin is the coalescence of compact binary systems (double neutron stars or a neutron star and a black hole), in which case SHBs are the electromagnetic counterparts of strong gravitational-wave sources. The theoretical and observational study of SHBs following the recent pivotal discoveries is reviewed, along with new theoretical results that are presented here for the first time.