cssi/SciSciGPT-SciSciNet huggingface dataset:
Reconstruction of Markov Random Fields from Samples: Some Observations and Algorithms

Markov random fields are used to model high dimensional distributions in a number of applied areas. Much recent interest has been devoted to the reconstruction of the dependency structure from independent samples from the Markov random fields. We analyze a simple algorithm for reconstructing the underlying graph defining a Markov random field on $n$ nodes and maximum degree $d$ given observations. We show that under mild nondegeneracy conditions it reconstructs the generating graph with high probability using $\Theta(d \epsilon^{-2}\delta^{-4} \log n)$ samples, where $\epsilon,\delta$ depend on the local interactions. For most local interactions $\epsilon,\delta$ are of order $\exp(-O(d))$. Our results are optimal as a function of $n$ up to a multiplicative constant depending on $d$ and the strength of the local interactions. Our results seem to be the first results for general models that guarantee that the generating model is reconstructed. Furthermore, we provide explicit $O(n^{d+2} \epsilon^{-2}\delta...
Put Your Science to Work: The Take‐Charge Career Guide for Scientists

This is the first of an occasional column in which the author or authors of a book recently published byAGU will be interviewed and their new book discussed. In this issue, Eos talks with Peter S. Fiske, the author of Put Your Science to Work: The Take-Charge Career Guide for Scientists. This is an update to his 1996 best-seller, To Boldly Go: A Practical Career Guide for Scientists, which became a best-seller for its comprehensive, hands-on guidance to scientists and scientistsin-training about the full range of professional opportunties open to them—including non-traditional ones—and how best to achieve success in them.
Simplified analysis of mascon modification of Apollo-type orbits

Apollo close lunar orbits have exhibited pronounced and unpredicted irregularities in successive passes over the near side of the Moon. Recently detected large mass concentrations (mascons) beneath the lunar surface are suspected to be the cause, but the lack of accurate values of a multitude of higher gravity harmonics precludes precise orbital corrections by standard methods. Estimates of orbital variations generated by an isolated mascon are obtained in this paper by a direct short-arc perturbation technique suggested by d'Alembert's comet swingby calculation. Each mascon ‘encounter’ provides an abrupt decrease of flight path angle, seen as a kink in the nominal orbit, expressible in terms of the nominal orbital motion and the mascon characteristics. Multiple mascon perturbations are found by superposition, leading to criteria for minimizing the navigational hazards presented by mascon lumpiness of the Moon's structure. It is noted that Lagrange found an integral of the equations of motion of a particle attracted to two fixed centers, of which the present problem is a special case, but his method did not lead to direct physical interpretations.
Design of a differential distributed amplifier and oscillator using close-packed interleaved transmission lines

The design of a differential distributed amplifier using close-packed transmission lines is discussed along with the implementation of a differential distributed oscillator. Efficient layout techniques for the implementation of these circuits are demonstrated. A differential distributed amplifier with 25 GHz of bandwidth and 7.5 dB of gain is presented as a design example. The amplifier can also be configured as a 9.2 GHz distributed oscillator with -6 dBm single-ended output power, phase noise of -103 dBc/Hz at a 1 MHz offset, and a 17% tuning range.
Large field cutoffs make perturbative series converge

Abstract For λφ4 problems, convergent perturbative series can be obtained by cutting off the large field configurations. The modified series converge to values exponentially close to the exact ones. For λ larger than some critical value, the method outperforms Pade approximants and Borel summations. We discuss some aspects of the semi-classical methods used to calculate the modified Feynman rules and estimate the error associated with the procedure. We provide a simple numerical example where the procedure works despite the fact that the Borel sum has singularities on the positive real axis.
Surfaces in 4-Manifolds: Concordance, Isotopy, and Surgery

In this paper we will show that two surfaces of the same genus and homology class in a simply connected 4-manifold are concordant. We will show they are often topologically isotopic when their complements have cyclic fundamental group. Finally, we will show that if they are 0-concordant, then surgery on one is equivalent to surgery on the other.
Novel and selective α-substitution of ketones and other carbonyl compounds based on Pd-catalyzed cross coupling of α,β-unsaturated carbonyl derivatives containing α-halogen or α-metal groups ☆

Abstract The Pd-catalyzed cross coupling of either α-haloenones with organometals or α-metalloenones with organic halides is intrinsically more problematical than the corresponding reaction of β-substituted enones or ordinary alkenyl derivatives. Nonetheless, satisfactory procedures have been developed for cross coupling with organometals containing Zn, Sn, B and Cu to give α-organylenones in high yields. As in the other cases, organozincs generally display the highest reactivity. In highly demanding and/or delicate situations, some indirect protocols involving protection of carbonyl groups or their temporary reduction help overcome difficulties encountered in direct α-substitution. Conjugate reduction and conjugate addition of α-substituted enones provide the corresponding saturated carbonyl compounds in completely regiocontrolled manner. Together with the ability to accommodate unsaturated organic groups, such as aryl, alkenyl, and alkynyl, the new Pd-catalyzed α-substitution protocols developed since 1987 promise to become synthetic tools of widespread application.
LOCAL POLARITON STATES IN POLAR CRYSTALS WITH IMPURITIES

Abstract We show that an impurity embedded in an ionic crystal can give rise to a novel kind of local states. These states exist within a polariton gap of a material and are a mix of excitations of the crystal, such as phonons or excitons, and the transverse electromagnetic field. Electromagnetic components of the states along with the corresponding excitations of the material are localized in the vicinity of an impurity.
An assessment of antineutrino detection as a tool for monitoring nuclear explosions

The antineutrino is the only real‐time inherently nuclear signature from a fission explosion that propagates great distances through air, water, and ground. The size and sensitivity of antineutrino detectors has increased dramatically in the last decade, and will continue to do so in the next, thanks in part to the renewed interest in neutrino physics brought on by the mounting evidence that neutrinos may have mass. The evolution of antineutrino detectors, and the evident interest of the signature as a means for monitoring nuclear tests motivates this review of the capabilities of existing and possible future detectors as test ban verification tools. Existing liquid scintillator ion‐ization detectors, operating a few tens of meters below the Earth's surface and containing a few thousand tons of active material, could be used to monitor an area of a few square kilometers for nuclear explosions at the 1 kt level. Purified water Cerenkov detectors of sizes comparable to existing detectors (50,000 m3) could b...
Incentives, Targeting, and Firm Performance: An Analysis of Non-executive Stock Options

We examine whether options granted to non-executive employees affect firm performance. Using new data on option programs, we explore the link between broad-based option programs, option portfolio implied incentives, and firm operating performance, utilizing an instrumental variables approach to identify causal effects. Firms whose employee option portfolios have higher implied incentives exhibit higher subsequent operating performance. Intuitively, the implied incentive-performance relation is concentrated in firms with fewer employees and in firms with higher growth opportunities. Additionally, the effect is concentrated in firms that grant options broadly to non-executive employees, consistent with theories of cooperation and mutual monitoring among co-workers. (JEL J33, D23, G30, 039, 141, M40, M52, M54)
On Solving Kepler's Equation

Intrigued by the recent advances in research on solving Kepler's equation, we have attacked the problem too. Our contributions emphasize the unified derivation of all known bounds and several starting values, a proof of the optimality of these bounds, a very thorough numerical exploration of a large variety of starting values and solution techniques in both mean anomaly/eccentricity space and eccentric anomaly/eccentricity space, and finally the best and simplest starting value/solution algorithm: M + e and Wegstein's secant modification of the method of successive substitutions. The very close second is Broucke's bounds coupled with Newton's second-order scheme.
Porous Metals from Colloidal Templates

This article reviews the synthesis, characterization, and potential applications of macroporous metals created from colloidal crystal templates. Porous metals formed in this way are over 70 % air—resulting in a net surface area of several square meters for a thin film only one centimeter across—and are sturdy enough to withstand routine handling. The voids of these samples are highly ordered over large length scales, and are interconnected by small windows that give solvents and gases ready access to the entire internal surface of the metal. Moreover, since the porous structure is ordered and the surface is relatively flat, the materials possess striking optical features reminiscent of highly blazed gratings. [1] Finally, the metal of the solid matrix is actually nanocrystalline. The unique combination of both micro- and nanostructure, as well as the material’s thin-film format, suggests that these samples may be useful in a wide variety of applications ranging from sensors to catalysis. [2,3] The application of templating methods to the synthesis of macroporous metals is in its early stages, though the general area of template chemistry has been very active over the last decade. The term templating refers to a technique that involves first the formation of a temporary medium, the template, whose interstices are then filled with another material. The template is subsequently removed chemically or thermally, leaving behind a porous material that is an inverse replica of the template’s microstructure. The architecture and form of the resulting porous sample thus depend directly on the characteristics of the starting template. Templates for the production of mesoporous materials, i.e., materials containing pores with diameters less than 50 nm, include liquid-crystalline surfactant assemblies [4‐6] and anodically etched alumina membranes. [7] Such materials can be used to form high-surface-area metals with pore sizes of 10‐50 nm, typically with cylindrical voids. [8‐11] The subject of this review, however, is the development of template routes for the production of macroporous metals, specifically materials with pore diameters between 200 and 1000 nm, in a free-standing format with highly ordered void structures.
High sensitivity photonic crystal biosensor incorporating nanorod structures for enhanced surface area

Abstract The surface area of a photonic crystal biosensor is greatly enhanced through the incorporation of a porous TiO 2 film possessing the structure of nanorods into the device. The film is deposited by the glancing angle deposition technique in an e-beam evaporation system. The sensitivity of high surface area sensors is compared with sensors without the high surface area coating. Results for detection of polymer films, large proteins and small molecules indicate up to a four-fold enhancement of detected adsorbed mass density.
Automating first-principles phase diagram calculations

Devising a computational tool that assesses the thermodynamic stability of materials is among the most important steps required to build a “virtual laboratory,” where materials could be designed from first principles without relying on experimental input. Although the formalism that allows the calculation of solid-state phase diagrams from first principles is well established, its practical implementation remains a tedious process. The development of a fully automated algorithm to perform such calculations serves two purposes. First, it will make this powerful tool available to a large number of researchers. Second, it frees the calculation process from arbitrary parameters, guaranteeing that the results obtained are truly derived from the underlying first-principles calculations. The proposed algorithm formalizes the most difficult step of phase diagram calculations, namely the determination of the “cluster expanison,” which is a compact representation of the configurational dependence of the alloy’s energy. This is traditionally achieved by a fit of the unknown interaction parameters of the cluster expansion to a set of structural energies calculated from first principles. We present a formal statistical basis for the selection of both the interaction parameters to include in the cluster expansion and the structures to use to determine them. The proposed method relies on the concepts of cross-validation and variance minimization. An application to the calculation of the phase diagram of the Si-Ge, CaO-MgO, Ti-Al, and Cu-Au systems is presented.
Studies on the Preparation of Protomycinolide IV: Enantioselective Synthesis of the C3–C9 Segment

Abstract The C3–C9 segment, (−)- 16 , of the polyene macrolide antibiotic protomycinolide IV ( 1a ) was prepared in optically pure form from commercially available methyl (S)-2-methyl-3-hydroxypropionate in 12 steps giving 17% yield.
Effects of substitution on low-temperature physical properties of LuFe2Ge2

The low-temperature magnetic phase transition in LuFe2Ge2 is thought to be associated with itinerant magnetism. The effects of Y and Sc substitutions on the Lu site, as well as Ru and Co substitutions on the Fe site, on the low-temperature magnetic phase transition of the LuFe2Ge2 compound have been studied in single crystals via microscopic, thermodynamic and transport measurements. On one hand, Co substitution suppresses the transition below our base temperature of 2 K even at our lowest substitution level. On the other hand, Sc substitution enhances the transition temperature, and Y or Ru substitution suppresses the transition to lower temperature. Phase diagrams for Y, Sc and Ru substitutions have been constructed and the possibility of a unifying, composite diagram is discussed.
Fascia Lata in Penile Reconstructive Surgery: A Reappraisal of the Fascia Lata Graft

Various surgical techniques and innovations have been applied to manage complex penile deformities. As an adjunct to penile reconstructive surgery, use of fascia lata, the superficial connective tissue structure of the thigh, may also be considered. Herein, four case reports are described in which fascia lata was applied: penile deformity associated with multiple unsuccessful penile prosthesis surgeries; penile prosthesis migration alter phalloplasty ; partial penile loss after ablative penile cancer surgery: and penile fibromatosis (Peyronie's disease). Fascia lata was autogenously obtained from the lateral thigh in all cases and used for, respectively, corporoplasty, penile prosthesis fixation, penile elongation, and tunica albuginea grafting. Surgeries were successful in every instance, and each patient reported satisfactory neophallic appearance and function postoperatively. The functional anatomy of the fascia lata was investigated further with lower extremity cadaveric dissections. For penile reconstructive surgery, fascia lata offers an autogenous source, it can be expeditiously obtained causing minimal morbidity, and it serves as a viahle graft material with good tensile strength. Its application derives from, and may extend to, other reconstructive surgeries.
Bounds on masses of bulk fields in string compactifications

In string compactification on a manifold X, in addition to the string scale and the normal scales of low-energy particle physics, there is a Kaluza-Klein scale 1/R associated with the size of X. We present an argument that generic string models with low-energy supersymmetry have, after moduli stabilization, bulk fields with masses which are parametrically lighter than 1/R. We discuss the implications of these light states for anomaly mediation and gaugino mediation scenarios.
High-dimensional data acquisition, computing, and visualization

Today, more complex data is generated and collected than ever before in human history. This avalanche creates opportunities and information as well as dif.culties and challenges. Many people and places are dedicated to data acquisition, computing, and visualization, and there is a great need for sharing information and approaches. We called for a special issue of papers in CiSE to investigate and study creative methods and systems in receiving, processing, and understanding high-dimensional data. The response was so overwhelming that we had to divide the theme into two separate issues part II will appear later this year.
Size of bile salt micelles: techniques, problems and results.

Abstract The current state of the knowledge of the size and the aggregation numbers of micelles formed In solutions of bile salts was evaluated. The experimental techniques considered include static light scattering, sedimentation equilibrium, membrane osmometry, sedimentation velocity and translational diffusion. The theoretical background of each method is briefly discussed, the working equations are summarized and the limitations of each technique are enumerated. Various interaction parameters and their effects on the measured micellar size are discussed. A brief survey of the recent experimental results from the author's laboratory is presented.
flyByNight: mitigating the privacy risks of social networking

Social networking websites are enormously popular, but they present a number of privacy risks to their users, one of the foremost of which being that social network service providers are able to observe and accumulate the information that users transmit through the network. We aim to mitigate this risk by presenting a new architecture for protecting information published through the social networking website, Facebook, through encryption. Our architecture makes a trade-off between security and usability in the interests of minimally affecting users' workflow and maintaining universal accessibility. While active attacks by Facebook could compromise users' privacy, our architecture dramatically raises the cost of such potential compromises and, importantly, places them within a framework for legal privacy protection because they would violate a user's reasonable expectation of privacy. We have built a prototype Facebook application implementing our architecture, addressing some of the limitations of the Facebook platform through proxy cryptography.
Anticoagulants and Antiplatelet Agents in Acute Ischemic Stroke Report of the Joint Stroke Guideline Development Committee of the American Academy of Neurology and the American Stroke Association (a Division of the American Heart Association)

Stroke remains a common and costly problem worldwide, but substantial advances have been made in recent decades in understanding stroke mechanisms, risk factors, and therapies. Because thrombosis plays an important role in the pathogenesis of ischemic stroke, drugs that interfere with hemostasis and clot formation such as anticoagulants and platelet antiaggregants commonly are used in the management of cerebrovascular disease. Considerable evidence supports the use of certain antithrombotic drugs in stroke prevention. However, because of limited supportive data, the use of these agents in patients with acute ischemic stroke remains controversial. In this report, we examine the published evidence relevant to the effects of anticoagulants and antiplatelet agents on acute ischemic stroke mortality, morbidity, and recurrence rates as well as associated ancillary benefits and risks of those treatments on the rates of deep vein thrombosis, pulmonary embolus, and cardiovascular complications. As part of these analyses, we also sought to determine whether there was evidence supporting differential efficacy of these drugs according to ischemic stroke subtypes. To prepare this report, experienced neurologists with a special interest in stroke diagnosis and management were appointed by the Quality Standards Subcommittee (QSS) and the Therapeutics and Technology Assessment (TTA) Subcommittee of the American Academy of Neurology, and the Stroke Council and Science Advisory and Coordinating Committee (SACC) of the American Heart Association (AHA). The QSS, TTA, Stroke Council and SACC are each charged with the responsibility of preparing evidence-based reports pertaining to medical practice issues including stroke. To facilitate the process of joint guideline development, a Steering Committee, chaired by representatives of the AAN and the American Stroke Association of the AHA, was appointed to discuss potential topics of wide interest to the stroke community. Choosing the role of anticoagulants and antiplatelet agents in acute ischemic stroke as the first topic, a Joint Writing …
Velocity dispersion of 335 galaxy clusters selected from the Sloan Digital Sky Survey: statistical evidence for dynamical interaction and against ram-pressure stripping

There has been plenty of observational evidence of cluster galaxy evolution, such as the Butcher-Oemler effect and the morphology-density relation. However, it is hard to identify the origin of cluster galaxy evolution, simply because it is difficult to trace the complicated process of galaxy evolution over a time-scale of several gigayears using observations that only give information about a single epoch. Here we show that gravitational interaction/friction between galaxies is the statistically dominant physical mechanism responsible for cluster galaxy evolution, and that the well-favoured ram-pressure stripping by the cluster gas is not statistically driving cluster galaxy evolution. We have constructed the largest composite cluster with 14 548 member galaxies out of 335 clusters with σ > 300 km s -1 carefully selected from the Sloan Digital Sky Survey. By measuring the velocity dispersions of various subsamples of galaxies in this composite cluster, we found that bright cluster galaxies (M z < -23) have significantly smaller velocity dispersion than faint galaxies (M z ≥ -23), with much greater precision than previous results (e.g. those of Adami et al.). We interpret this as direct evidence of the dynamical interaction/friction between cluster galaxies, where massive galaxies lose their velocity through energy equipartition during the dynamical interaction/friction with less massive galaxies. We also found that star-forming late-type galaxies have a larger velocity dispersion than passive late-type galaxies. This is inconsistent with the ram-pressure stripping model; since ram pressure is proportional to a v 2 (i.e. stronger for galaxies with high velocity), ram-pressure stripping cannot explain the observed trends of passive (evolved) galaxies having low velocity rather than high velocity. On the other hand, the result is again consistent with the dynamical galaxy-galaxy interaction/friction, where more evolved (passive) galaxies lose their velocity through dynamical interaction/friction.
Hospital implementation of health information technology and quality of care: are they related?

Recently, there has been considerable effort to promote the use of health information technology (HIT) in order to improve health care quality. However, relatively little is known about the extent to which HIT implementation is associated with hospital patient care quality. We undertook this study to determine the association of various HITs with: hospital quality improvement (QI) practices and strategies; adherence to process of care measures; risk-adjusted inpatient mortality; patient satisfaction; and assessment of patient care quality by hospital quality managers and front-line clinicians. We conducted surveys of quality managers and front-line clinicians (physicians and nurses) in 470 short-term, general hospitals to obtain data on hospitals’ extent of HIT implementation, QI practices and strategies, assessments of quality performance, commitment to quality, and sufficiency of resources for QI. Of the 470 hospitals, 401 submitted complete data necessary for analysis. We also developed measures of hospital performance from several publicly data available sources: Hospital Compare adherence to process of care measures; Medicare Provider Analysis and Review (MEDPAR) file; and Hospital Consumer Assessment of Healthcare Providers and Systems HCAHPS® survey. We used Poisson regression analysis to examine the association between HIT implementation and QI practices and strategies, and general linear models to examine the relationship between HIT implementation and hospital performance measures. Controlling for potential confounders, we found that hospitals with high levels of HIT implementation engaged in a statistically significant greater number of QI practices and strategies, and had significantly better performance on mortality rates, patient satisfaction measures, and assessments of patient care quality by hospital quality managers; there was weaker evidence of higher assessments of patient care quality by front-line clinicians. Hospital implementation of HIT was positively associated with activities intended to improve patient care quality and with higher performance on four of six performance measures.
Statistical magnetohydrodynamics and reversed-field-pinch quiescence

Abstract A statistical model of a bounded, incompressible, cylindrical magnetofluid is presented. This model predicts the presence of magnetic fluctuations about a cylindrically-symmetric, Bessel-function-model, mean magnetic field, which satisfies ∇ × 〈 B 〉 = μ〈 B 〉 . As Θ → 1.56, the model predicts that the significant region of the fluctuation spectrum narrows down to a single (coherent) m = 1 mode. An analogy between the Debye length of an electrostatic plasma and μ−1 suggests the physical validity of the model's prediction of 〈δ B ( r )δ B ( r ′)〉 when | r − r ′| ⩾ μ −1 .
Cubic surfaces with special periods

We show that the vector of period ratios of a cubic surface is rational over Q(ω), where ω = exp(2πi/3) if and only if the associate abelian variety is isogeneous to a product of Fermat elliptic curves. We also show how to construct cubic surfaces from a suitable totally real quintic number field K0. The ring of rational endomorphisms of the associated abelian variety is K = K0(ω).
On the non-perturbative gluon mass and heavy quark physics

Abstract We study a recently proposed gauge invariant, non-local pure gauge observable, which is equivalent to the gluon propagator in a certain gauge. The correlator describes a gluon coupled to static sources and decays with eigenvalues of the Hamiltonian, permitting a non-perturbative definition of a gluonic parton mass. Detailed numerical tests of the observable are performed in SU(2) gauge theories in 2+1 dimensions. In a Higgs model it reproduces the physical W-boson mass, while in a confining theory its non-local nature results in almost exclusive projection onto torelonic states. However, the gluon mass can also be related to the mass difference between the lowest gluelumps, i.e., gluon configurations bound to adjoint sources. Its value is computed in SU(2) pure gauge theory in 2+1 dimensions to be m A =0.360(19) g 2 , which plays an important role as “magnetic mass” of the four-dimensional theory at high temperatures. The same quantity is found to determine the mass splitting between vector and scalar mesons in the three-dimensional theory. In SU(3) pure gauge theory in 3+1 dimensions the corresponding gluelump splitting yields m A ≈370 MeV. Possible relations of this quantity with the QCD heavy meson spectrum are discussed.
To code or not to code across time: space-time coding with feedback

Space-time codes leverage the availability of multiple antennas to enhance the reliability of communication over wireless channels. While space-time codes have initially been designed with a focus on open-loop systems, recent technological advances have enabled the possibility of low-rate feedback from the receiver to the transmitter. The focus of this paper is on the implications of this feedback in a single-user multi-antenna system with a general model for spatial correlation. We assume a limited feedback model, that is, a coherent receiver and statistical knowledge at both the ends, along with B bits of error-free quantized channel information at the transmitter. We study space-time coding with a family of linear dispersion (LD) codes that meet an additional orthogonality constraint so as to ensure low-complexity decoding. Our results show that, when the number of bits of feedback (B) is small, a space-time coding scheme that is equivalent to beamforming and does not code across time is optimal in a weak sense in that it maximizes the average received SNR. As B increases, this weak optimality transitions to optimality in a strong sense that is characterized by the maximization of average mutual information. Thus, from a system designer's perspective, our work suggests that beamforming may not only be attractive from a low-complexity viewpoint, but also from an information-theoretic viewpoint.
CJ-19,784, a new antifungal agent from a fungus, Acanthostigmella sp.

A new antifimgal agent, CJ-19, 784 (I), was isolated from the fermentation broth of a fungus, Acanthostigmella sp. CL12082. Based on spectroscopic analyses, structure of I was determined to be 3'-bromo-2', 5-dihydroxy-3, 7, 8-trimethoxy-flavone. Compound I inhibits the growth of pathogenic fungi, Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus with IC50 values of 0.11, 20 and 0.54 μg/ml, respectively.
THE SOLAR ARGON ABUNDANCE

The solar argon abundance cannot be directly derived by spectroscopic observations of the solar photosphere. The solar argon abundance is evaluated from solar wind measurements, nucleosynthetic arguments, observations of B stars, H II regions, planetary nebulae, and noble gas abundances measured in Jupiter's atmosphere. These data lead to a recommended argon abundance of N(Ar) = 91,200 ± 23,700 (on a scale where Si = 106 atoms). The recommended abundance for the solar photosphere [on a scale where log N(H) = 12] is A(Ar)photo = 6.50 ± 0.10, and taking element settling into account, the solar system (protosolar) abundance is A(Ar)solsys = 6.57 ± 0.10.
The intramolecular cation radical diels-alder reaction

Abstract The first examples of intramolecular cation radical Diels-Alder reactions have been established using trienes which cyclize to hydroindane systems. The extremely high endo stereoselectivity characteristic of the cation radical Diels-Alder reaction is effectively exploited to generate trans -hydroindanes with high selectivity.
Capacity Approaching Turbo Coding For Half-Duplex Relaying

In this paper, we develop capacity approaching turbo coding schemes for half-duplex relay systems as an extension of our previous work on coding for full-duplex relays. We consider the use of specific signal constellations (e.g., binary phase-shift keying) in transmission, develop practical coding schemes to be used at the source and the relay nodes, and describe a suitable information combining technique at the destination node. Unlike the full-duplex relay systems, the destination node does not perform joint decoding of multiple consecutive blocks; instead, it works with one frame at a time. Furthermore, for the half-duplex relaying scheme, the optimization of the length of the listening period for the relay node is an issue. By utilizing the information theoretical tools, we perform this optimization, and use it in our development of capacity approaching coding/decoding schemes. Specifically, when the fraction of time turns out to be less than the transmission rate, the relay node is unable to decode all the information bits transmitted, and a partial decoding approach has to be used. Through a comprehensive set of examples, we observe that the proposed scheme is promising to approach the corresponding information theoretical limits (bounds). In particular, for all the cases studied, we have obtained bit error rates of $10^{-5}$ or lower within 1–1.5 dB (in most cases, around within 1.2 dB) of the constrained capacity under a variety of channel conditions. Extensions of the proposed scheme to coded modulation and to multiple-input multiple-output systems are also described.
Synthesis and evaluation of imidazo[1,5-a]pyrazines as corticotropin releasing hormone receptor ligands

A novel series of imidazo[1,5-a]pyrazines was synthesized and evaluated as corticotropin releasing hormone (CRH) receptor ligands. SAR studies focused primarily on dialkylamino side chain optimization. SAR of the aryl and small alkyl substituents was also explored.
Reconstructive management of patients with greater than 80 per cent TBSA burns

Abstract With improving acute burn care, greater numbers of patients are surviving large burns. Meshed skin grafts or cultured epithelial autografts are often required to achieve rapid wound closure, even in areas such as the hands or face. This, plus the lack of suitable donor tissue for reconstruction, is mandating a change in reconstructive principles. Twenty-eight patients surviving ≥80 per cent TBSA full skin thickness burns were evaluated using two specially devised instruments (Inventory of Potential Reconstructive Needs; Donor Tissue Surveillance). A total of 564 reconstructive needs were identified in the 28 patients, an average of 20.1 per patient. There were 265 defects in the head and neck, 143 in the upper extremities, and 156 in the torso/lower extremities. The injured anatomical units most frequently identified were the hand (74), trunk (60), nose/nasolabial fold (48), mouth (46), ankle/foot (42), neck (31) and check (28). The Donor Tissue Surveillance form revealed that the necessary donor tissue was frequently not available, and when available, was often of poor quality. These facts require a different set of priorities for reconstruction of the massively burned patient. No longer can a simple stepwise plan of active function, passive function, and aesthetic needs be followed. The patient and family desires must be combined with a realistic outlook by the entire burn team to determine the most judicious and efficient use of available donor tissue to meet the reconstructive needs.
Image information by means of speckle-pattern processing*

When a laser beam is reflected from a diffuse surface, a granular scattering distribution is commonly observed, called a speckle pattern. We will discuss some of its ramifications: (1) this pattern is the time-independent analog of the signal used in the classic Hanbury Brown–Twiss stellar interferometer of the 1950’s; (2) this pattern can be processed by standard incoherent optical techniques to yield information pertaining to the object radiance distribution; (3) this same signal, when processed by coherent-optical techniques, is equivalent to the Gabor on-axis hologram or the Fourier-transform hologram, depending on the specific source configuration; and (4) signals processed by all of the above techniques are comparatively insensitive to atmospheric turbulence. An experiment is performed to illustrate the procedure of item (2) and then modified to show assertion (4).
Preferential Oxidative Addition in Palladium(0)-Catalyzed Suzuki Cross-Coupling Reactions of Dihaloarenes with Arylboronic Acids

The study of Pd(0)-/t-Bu3P system as a powerful catalyst for the cross-coupling of n,m-dihaloarenes with 1 equiv of arylboronic acids is described. Our work demonstrated that the fate of the regenerated Pd(0) catalyst can be controlled when the appropriate ligand is employed. The results described here may lead to the development of new, efficient processes to conjugate polymers with controlled length which are potentially useful in molecular electronics.
The environmental dependence of galaxy clustering in the Sloan Digital Sky Survey

A generic prediction of hierarchical clustering models is that the mass function of dark haloes in dense regions in the Universe should be top-heavy. We provide a novel test of this prediction using a sample of galaxies drawn from the Sloan Digital Sky Survey (SDSS). To perform the test, we compare measurements of galaxy clustering in dense and underdense regions. We find that galaxies in dense regions cluster significantly more strongly than those in less dense regions. This is true over the entire 0.1-30 Mpc pair separation range for which we can make accurate measurements. We make similar measurements in realistic mock catalogues in which the only environmental effects are those which arise from the predicted correlation between halo mass and environment. We also provide an analytic halo model based calculation of the effect. Both the mock catalogues and the analytic calculation provide rather good descriptions of the SDSS measurements. Thus, our results provide strong support for hierarchical models. They suggest that, unless care is taken to study galaxies at fixed mass, correlations between galaxy properties and the surrounding environment are almost entirely due to more fundamental correlations between galaxy properties and host halo mass, and between halo mass and environment.
Solar corona at high resolution

The earth's surface is shielded from solar X rays almost completely by the atmosphere. It is, therefore, necessary to place X-ray detectors on rockets or orbiting satellites. Solar rays were detected for the first time in the late 1940's, using V-2 rockets. In 1960, the first true X-ray images of the sun were obtained with the aid of a simple pinhole camera. The spatial resolution of the X-ray images could be considerably improved by making use of reflective optics, operating at grazing incidence. Aspects of X-ray mirror developments are discussed along with the results obtained in coronal studies utilizing the new devices for the observation of solar X-ray emission. It is pointed out that the major achievements of the Skylab missions were due primarily to the unique opportunity to obtain data over an extended period of time. Attention is given to normal incidence X-ray optics, achievements possible by making use of high spatial resolution optics, and details of improved mirror design.
The Migration and Adaptation of American Indians to Los Angeles

The city of Los Angeles has the largest population of American Indians in the United States. In this city, the Indians are actively creating a pan-Indian subculture which accommodates their aboriginal history and reservation culture to the newer world of urban living. Athletic leagues, Christian churches, and other institutions Euro-American in character are focusing on their Indian membership and identity with such activities as social centers, annual fairs and yearly Christmas parties. Tradition-oriented dance clubs flourish.
Commonsense Knowledge, Ontology and Ordinary Language

Over two decades ago a "quite revolution" overwhelmingly replaced knowledge- based approaches in natural language processing (NLP) by quantitative (e.g., statistical, corpus-based, machine learning) methods. Although it is our firm belief that purely quanti- tative approaches cannot be the only paradigm for NLP, dissatisfaction with purely engi- neering approaches to the construction of large knowledge bases for NLP are somewhat justified. In this paper we hope to demonstrate that both trends are partly misguided and that the time has come to enrich logical semantics with an ontological structure that reflects our commonsense view of the world and the way we talk about in ordinary language. In this paper it will be demonstrated that assuming such an ontological structure a number of challenges in the semantics of natural language (e.g., metonymy, intensionality, copredica- tion, nominal compounds, etc.) can be properly and uniformly addressed.
Segue 2: The Least Massive Galaxy

Segue 2, discovered by Belokurov et al., is a galaxy with a luminosity of only 900 L_☉. We present Keck/DEIMOS spectroscopy of 25 members of Segue 2—a threefold increase in spectroscopic sample size. The velocity dispersion is too small to be measured with our data. The upper limit with 90% (95%) confidence is σ_v < 2.2 (2.6) km s^(–1), the most stringent limit for any galaxy. The corresponding limit on the mass within the three-dimensional half-light radius (46 pc) is M_(1/2) < 1.5 (2.1) × 10^5 M_☉. Segue 2 is the least massive galaxy known. We identify Segue 2 as a galaxy rather than a star cluster based on the wide dispersion in [Fe/H] (from –2.85 to –1.33) among the member stars. The stars' [α/Fe] ratios decline with increasing [Fe/H], indicating that Segue 2 retained Type Ia supernova ejecta despite its presently small mass and that star formation lasted for at least 100 Myr. The mean metallicity, 〈[Fe/H]〉 = -2.22 ± 0.13 (about the same as the Ursa Minor galaxy, 330 times more luminous than Segue 2), is higher than expected from the luminosity-metallicity relation defined by more luminous dwarf galaxy satellites of the Milky Way. Segue 2 may be the barest remnant of a tidally stripped, Ursa Minor-sized galaxy. If so, it is the best example of an ultra-faint dwarf galaxy that came to be ultra-faint through tidal stripping. Alternatively, Segue 2 could have been born in a very low mass dark matter subhalo (v_(max) < 10 km s^(–1)), below the atomic hydrogen cooling limit.
D-branes in nongeometric backgrounds

``T-fold backgrounds are generically-nongeometric compactifications of string theory, described by Tn fibrations over a base N with transition functions in the perturbative T-duality group. We review Hull's doubled torus formalism, which geometrizes these backgrounds, and use the formalism to constrain the D-brane spectrum (to leading order in gs and α') on Tn fibrations over S1 with O(n,n;) monodromy. We also discuss the (approximate) moduli space of such branes and argue that it is always geometric. For a D-brane located at a point on the base N, the classical ``D-geometry'' is a Tn fibration over a multiple cover of N.
Intuitionistic Completeness of First-Order Logic

Abstract We constructively prove completeness for intuitionistic first-order logic, iFOL, showing that a formula is provable in iFOL if and only if it is uniformly valid in intuitionistic evidence semantics as defined in intuitionistic type theory extended with an intersection operator. Our completeness proof provides an effective procedure that converts any uniform evidence into a formal iFOL proof. Uniform evidence can involve arbitrary concepts from type theory such as ordinals, topological structures, algebras and so forth. We have implemented that procedure in the Nuprl proof assistant. Our result demonstrates the value of uniform validity as a semantic notion for studying logical theories, and it provides new techniques for showing that formulas are not intuitionistically provable. Here we demonstrate its value for minimal and intuitionistic first-order logic.
Directional cell search for millimeter wave cellular systems

Millimeter wave (mmW) bands between 30 and 300 GHz are considered a promising candidate for next-generation cellular networks to relieve spectral congestion in conventional cellular frequencies. However, cellular communication at these frequencies will likely require highly directional transmissions to achieve suitable signal range. This reliance on directional beamforming complicates initial cell search since the mobile and base station must jointly search over a potentially large angular directional space to locate a suitable path to initiate communication. This paper proposes a directional cell search procedure where each base station periodically transmits synchronization signals in randomly varying directions. Detectors are derived for this synchronization signal based on a Generalized Likelihood Ratio Test (GLRT) for the case where (i) the mobile has only analog beamforming (where the mobile can “look” in only direction at a time) and (ii) digital beamforming where the mobile has access to digital samples from all antennas. Simulations under realistic parameters demonstrate that mobiles may not be able to achieve suitable detection performance with analog beamforming alone. In contrast, digital beamforming offers dramatically better performance. We argue that the additional power consumption cost of digital beamforming can be offset by using very low quantization rates with minimal performance loss, thus arguing that low-rate fully digital front-ends may be a better design choice for directional cell search.
On Brenti's conjecture about the log-concavity of the chromatic polynomial

The chromatic polynomial is a well studied object in graph theory. There are many results and conjectures about the log-concavity of the chromatic polynomial and other polynomials related to it. The location of the roots of these polynomials has also been well studied. One famous result due to Sokal and Borgs provides a bound on the absolute value of the roots of the chromatic polynomial in terms of the highest degree of the graph. We use this result to prove a modification of a log-concavity conjecture due to Brenti. The original conjecture of Brenti was that the chromatic polynomial is log-concave on the natural numbers. This was disproved by Paul Seymour by presenting a counterexample. We show that the chromatic polynomial P"G(q) of graph G is in fact log-concave for all q>[email protected]+1 for an explicit constant C<10, where @D denotes the highest degree of G. We also provide an example which shows that the result is not true for constant C smaller than 1.
A sharp bound for the inscribed radius under mean curvature flow

We consider a family of embedded, mean convex hypersurfaces which evolve by the mean curvature flow. It follows from general results of White that the inscribed radius at each point on the hypersurface is at least $$\frac{c}{H}$$ , where $$c$$ is a positive constant that depends only on the initial data. Andrews recently gave a new proof of that fact using the maximum principle. In this paper, we show that the inscribed radius is at least $$\frac{1}{(1+\delta ) \, H}$$ at each point where the curvature is sufficiently large.
Role of drug metabolism in drug discovery and development.

Metabolism by the host organism is one of the most important determinants of the pharmacokinetic profile of a drug. High metabolic lability usually leads to poor bioavailability and high clearance. Formation of active or toxic metabolites will have an impact on the pharmacological and toxicological outcomes. There is also potential for drug-drug interactions with coadministered drugs due to inhibition and/or induction of drug metabolism pathways. Hence, optimization of the metabolic liability and drug-drug interaction potential of the new chemical entities are some of the most important steps during the drug discovery process. The rate and site(s) of metabolism of new chemical entities by drug metabolizing enzymes are amenable to modulation by appropriate structural changes. Similarly, the potential for drug-drug interactions can also be minimized by appropriate structural modifications to the drug candidate. However, the optimization of the metabolic stability and drug-drug interaction potential during drug discovery stage has been largely by empirical methods and by trial and error. Recently, a lot of effort has been applied to develop predictive methods to aid the optimization process during drug discovery and development. This article reviews the role of drug metabolism in drug discovery and development.