cssi/SciSciGPT-SciSciNet huggingface dataset:
Dielectric function and plasmons in graphene

The electromagnetic response of graphene and the spectrum of collective plasmon excitations are studied as a function of wave vector and frequency. Our calculation is based on the tight-binding band structure, including both valleys. As a result, near the Dirac points we find plasmons whose dispersion is similar to that obtained in the single-valley approximation by Dirac fermions with some anisotropy though. In contrast to the calculation for a single Dirac cone, we find a stronger damping of the plasmon modes due to interband absorption. Our calculation also reveals effects due to deviations from the linear Dirac spectrum as we increase the Fermi energy, indicating an anisotropic behavior with respect to the wave vector of the external electromagnetic field.
Optimal constrained representation and filtering of signals.

Abstract A random signal is observed in independent random noise. We are addressing the problem of finding the optimum signal estimate that is constrained to lie in a given linear subspace. The optimality is defined in the sense of weighted mean square error. In the second step, we find the optimum linear subspace of given dimensionality. It is shown to be the linear manifold spanned by the eigenvectors of the simultaneous diagonalization of the signal and noise covariance, that correspond to the largest eigenvalues. The result is valid for both discrete and continuous time. For large observation time and stationary signals, it is shown that the constrained optimal estimate is determined by the two spectral densities and a weighted Fourier Transform of the noise observations. The above result applies to both discrete time and continuous time signals. The Wiener filter emerges as a special case of the constrained filtering estimate, when the linear subspace is enlarged to coincide with the total measurement space.
Effect of Dietary Calcium on Urinary Oxalate Excretion After Oxalate Loads

An experimental model that allowed differentiation between endogenously and exogenously derived urinary oxalate was used to assess the effect of different forms and doses of ingested calcium on oxalate absorption and excretion. In replication 1 (R-1), subjects participated in three oxalate load (OL) tests: baseline (OL alone), calcium carbonate (OL with concomitant calcium carbonate ingestion), and calcium citrate malate (CCM) (OL with concomitant CCM ingestion). The calcium salts each provided 300 mg elemental Ca. OLs consisted of 180 mg unlabeled and 18 mg 1,2[13C2]oxalic acid. In R-2, subjects participated in four OL tests: baseline (OL alone) and OLs administered concomitantly with 100, 200, or 300 mg Ca. Timed urine samples after the OL were collected at 2-h intervals for the initial 6 h and samples were pooled into 9-h aliquots for the remaining 18 h of the 24-h period. In R-1, 24-h mean exogenous oxalate decreased (P < 0.05) after the OL from 36.2 mg (baseline) to 16.1 mg (after calcium carbonate) and to 14.3 mg (after CCM) whereas endogenous oxalate remained relatively constant. Mean 24-h oxalate absorption decreased significantly from that at the time of the baseline treatment (18.3%) after both calcium carbonate (8.1%) and CCM (7.2%) treatments. In R-2, mean 24-h oxalate absorption was significantly lower after 200 (5.9%) and 300 (7.6%) mg Ca than after 100 mg Ca (9.1%) and the OL alone (11.3%). Concomitant meal ingestion significantly decreased oxalate absorption in the absence of dietary calcium but not in association with the 300-mg Ca treatment. The overall data provide definitive evidence that dietary calcium can reduce oxalate absorption and excretion. Calcium carbonate and CCM were equally effective in this regard and a minimum of 200 mg elemental Ca maximized this effect in conjunction with an oxalic acid intake of 198 mg.
Improved Fokker-Planck Equation for Resonance-Line Scattering

A new Fokker-Planck equation is developed for treating resonance-line scattering, which is especially relevant to the treatment of Lyα in the early universe. It is a "corrected" form of the equation of Rybicki & Dell'Antonio that now obeys detailed balance, so the approach to thermal equilibrium is properly described. The new equation takes into account the energy changes due to scattering off moving particles, the recoil term of Basko, and stimulated scattering. One result is a surprising unification of the equation for resonance-line scattering and the Kompaneets equation. An improved energy exchange formula due to resonance-line scattering is derived. This formula is compared to previous formulas of Madau and coworkers and Chen & Miralda-Escude.
Semistar Operations on Dedekind Domains

We show that the structure of the lattice Semistar(D) of semistar operations on a Dedekind domain D depends only on the cardinality of the set Max(D) of maximal ideals of D, and we give an explicit construction of Semistar(D) when Max(D) is finite. As a corollary we show that if n = |Max(D)| is finite; we compute |Semistar(D)| if |Max(D)| ≤7; and we show that if Max(D) is infinite then Semistar(D) has cardinality 22|Max(D)|.
Insulin Resistance: the Link Between Obesity and Cardiovascular Disease

Insulin-mediated glucose disposal varies at least sixfold in apparently healthy individuals. The adverse effect of decreases in the level of physical fitness on insulin sensitivity is comparable to the untoward impact of excess adiposity, with each accounting for approximately 25% of the variability of insulin action. It is the loss of insulin sensitivity that explains why obese individuals are more likely to develop cardiovascular disease, but not all overweight/obese individuals are insulin resistant. At a clinical level, it is important to identify those overweight individuals who are also insulin resistant and to initiate the most intensive therapeutic effort in this subgroup. Finally, it appears that the adverse impact of overall obesity, as estimated by body mass index, is comparable to that of abdominal obesity, as quantified by waist circumference.
Reactions of aromatics and naphthenes with alkanes over a Pt/ZrO2/SO4 catalyst

Abstract We have found that Pt/ZrO 2 /SO 4 , in the presence of hydrogen, catalyzes the isomerization and cracking of alkanes to give carbenium ions which (a) react with aromatics to yield alkylaromatics as well as alkylated naphthenes and (b) alkylate naphthenic compounds. The products vary with the nature of the aromatic, the length of the paraffinic chain and whether the paraffinic component is added as such or is part of the aromatic ring. For example, little reaction occurs with phenol and a long chain alkane such as dodecane but p -dodecylphenol and anisole react to give alkylated aromatics. The nature of the aromatic can control the distribution of products obtained from added alkanes. Ethylene and even polypropylene alkylate aromatics in the presence of Pt/ZrO 2 /SO 4 . The reactions and products obtained are varied and further investigation of the nature of the catalytic action of Pt/ZrO 2 /SO 4 is being pursued.
Associations Among Children's Social Goals, Responses to Peer Conflict, and Teacher-Reported Behavioral and Academic Adjustment at School

This study examined associations among children's agentic (social influence, status, power) and communal (relationship, affiliation) goals for peer interaction, cognitive and affective responses to hypothetical peer conflict, and teacher-reported achievement and behavior at school (N = 367; M age = 9.9 years). Agentic goals were positively associated with children's anger and aggressive strategies in peer conflicts, as well as low academic achievement. Communal goals were positively associated with prosocial strategies, sadness, and embarrassment in conflicts, as well as high achievement and fewer teacher reported behavioral difficulties at school. In line with other recent research, the findings underline the importance of considering children's motives for peer interaction when examining their social and academic adjustment at school.
Synthesis of α,α′-trans-Oxepanes through an Organocatalytic Oxa-conjugate Addition Reaction

Oxepanes are found in a wide range of natural products; however, they are challenging synthetic targets due to enthalpic and entropic barriers. Organocatalytic oxa-conjugate addition reactions promoted by the gem-disubstituent (Thorpe–Ingold) effect stereoselectively provided α,α′-trans-oxepanes. In addition, the potential of an organocatalytic tandem oxa-conjugate addition/α-oxidation was demonstrated in a rapid generation of molecular complexity. These organocatalytic oxa-conjugate addition reactions would provide powerful tools for the synthesis of natural products that contain highly functionalized oxepanes.
Can computer personalities be human personalities

The claim that computer personalities can be human personalities was tested by demonstrating that (1) computer personalities can be easily created using a minimal set of cues, and (2) that people will respond to these personalities in the same way they would respond to similar human personalities. The present study focused on the "similarity-attraction hypothesis," which predicts that people will prefer to interact with others who are similar in personality. In a 2 × 2, balanced, between-subjects experiment (n = 48), dominant and submissive subjects were randomly matched with a computer that was endowed with the properties associated with dominance or submissiveness. Subjects recognized the computer's personality type, distinct from friendliness and competence. In addition, subjects not only preferred the similar computer, but they were more satisfied with the interaction. The findings demonstrate that personality does not require richly defined agents, sophisticated pictorial representations, nautral language processing, or artificial intelligence. Rather, even the most superficial manipulations are sufficient to exhibit personality, with powerful effects.
Black hole entropy in M theory

Extremal black holes in M-theory compactification on M × S1 are microscopically represented by fivebranes wrapping P × S1, where M is a Calabi-Yau threefold and P is a four-cycle in M. Additional spacetime charges arise from momentum around the S1 and expectation values for the self-dual three-form field strength in the fivebrane. The microscopic entropy of the fivebrane as a function of all the charges is determined from a two-dimensional (0,4) sigma model whose target space includes the fivebrane moduli space. This entropy is compared to the macroscopic formula. Precise agreement is found for both the tree-level and one-loop expressions.
Clinical Screening and Genetic Testing

Clinical screening is most effective in diseases in which the disease in its earliest form and may not have symptoms or signs but can be readily diagnosed with an inexpensive, noninvasive test. This article discusses the general principles of genetic disease architecture that can guide screening and diagnostic approaches for all of the cardiomyopathies and inherited diseases. It addresses how the genetic architecture of the trait guides, and how clinical characteristics of the disease influence, a clinical screening approach.
An efficient, portable authoring language for microcomputers

An authoring language is a programming language that is optimized in some way for the efficient production of computer assisted instruction lessons. This paper summarizes nearly twenty years of experimentation and development of authoring languages at the University of Minnesota, then presents the main characteristics of a new language that embodies many of the lessons learned over this period. The new language is called AL, for author language. Based on Pascal, it is easily transportable across most microcomputers, requires no special operating system or tools, and makes no assumptions regarding educational style or method. It was designed to maximize efficiency over the entire process of authoring, testing, distribution, and maintenance of lessons. This is in stark contrast to most CAI languages, which were designed primarily to simplify the author interface.The paper is divided into five sections. The first recounts experimentation in the 1960's at Minnesota with one of the first authoring languages, and catalogs its most important deficiencies. The second section describes a major effort to support CAI using a FORTRAN language preprocessor on a large interactive timesharing system. The third section describes how this approach was successfully adapted to microcomputers using Pascal. The fourth section describes the new AL language, which incorporates the lessons of the extensive trials with the previous efforts. The final section briefly compares AL with four other authoring languages for the IBM PC.
Predictive end-point trajectory control of elastic manipulators

This article presents an approach to end-point trajectory control of elastic manipulators based on the nonlinear predictive control theory. Although this approach is applicable to manipulators of general configuration, only planar flexible multi-link manipulators are considered. A predictive control law is derived by minimizing a quadratic function of the trajectory error of the end-points of each link, elastic modes, and control torques. This approach avoids the instability of the zero dynamics encountered in the controller design using feedback linearization and variable structure control techniques for end-point control. Furthermore, the derived predictive controller is robust to uncertainty in the system parameters. Simulation results are presented for a one-link flexible manipulator to show that in the closed-loop system accurate end-point trajectory control and vibration damping can be accomplished.
Enhancement of chemical measurement techniques by real-time computer interaction

The small, dedicated, laboratory computer can provide enhanced capability for electroanalytical measurement techniques in the chemistry laboratory. The work described here is based primarily on three recent publications by Perone, Jones, and Gutknecht. The particular electrochemical analysis techniques to which computerization has been applied are stationary electrode polarography (SEP), and the closely-related derivative voltammetry. However, the principles and methodology described should be generally applicable to other electroanalytical techniques, and, perhaps, to chemical experimentation, in general.
Consensus and Coherence in Fractal Networks

We consider first- and second-order consensus algorithms in networks with stochastic disturbances. We quantify the deviation from consensus using the notion of network coherence, which can be expressed as an $H_{2}$ norm of the stochastic system. We use the setting of fractal networks to investigate the question of whether a purely topological measure, such as the fractal dimension, can capture the asymptotics of coherence in the large system size limit. Our analysis for first-order systems is facilitated by connections between first-order stochastic consensus and the global mean first passage time of random walks. We then show how to apply similar techniques to analyze second-order stochastic consensus systems. Our analysis reveals that two networks with the same fractal dimension can exhibit different asymptotic scalings for network coherence. Thus, this topological characterization of the network does not uniquely determine coherence behavior. The question of whether the performance of stochastic consensus algorithms in large networks can be captured by purely topological measures, such as the spatial dimension, remains open.
Land development and preservation over time and under uncertainty: a review and a research agenda

Abstract The combination of a rising interest in sustainable natural resource use and the increasingly fractious nature of the interactions between developers and preservationists has led to renewed interest in the question of appropriate natural resource management. In this paper I consider the question of land development and preservation over time and under uncertainty. I first review the extant literature and then I discuss its shortcomings. Next, I propose a research agenda which will enable us to shed light on some important management questions faced by land developers.
Three-dimensional Modeling of Hot Jupiter Atmospheric Flows

We present a three-dimensional hot Jupiter model, extending from 200 bar to 1 mbar, using the Intermediate General Circulation Model from the University of Reading. Our horizontal spectral resolution is T31 (equivalent to a grid of 48 × 96), with 33 logarithmically spaced vertical levels. A simplified (Newtonian) scheme is employed for the radiative forcing. We adopt a physical setup nearly identical to the model of HD 209458b by Cooper & Showman to facilitate a direct model inter-comparison. Our results are broadly consistent with theirs but significant differences also emerge. The atmospheric flow is characterized by a super-rotating equatorial jet, transonic wind speeds, and eastward advection of heat away from the dayside. We identify a dynamically induced temperature inversion ("stratosphere") on the planetary dayside and find that temperatures at the planetary limb differ systematically from local radiative equilibrium values, a potential source of bias for transit spectroscopic interpretations. While our model atmosphere is quasi-identical to that of Cooper & Showman and we solve the same meteorological equations, we use different algorithmic methods, spectral-implicit versus grid-explicit, which are known to yield fully consistent results in the Earth modeling context. The model discrepancies identified here indicate that one or both numerical methods do not faithfully capture all of the atmospheric dynamics at work in the hot Jupiter context. We highlight the emergence of a shock-like feature in our model, much like that reported recently by Showman et al., and suggest that improved representations of energy conservation may be needed in hot Jupiter atmospheric models, as emphasized by Goodman.
Uniqueness in the Inversion of Inaccurate Gross Earth Data

A gross Earth datum is a single measurable number describing some property of the whole Earth, such as mass, moment of inertia, or the frequency of oscillation of some identified elastic-gravitational normal mode. We suppose that a finite set G of gross Earth data has been measured, that the measurements are inaccurate, and that the variance matrix of the errors of measurement can be estimated. We show that some such sets G of measurements determine the structure of the Earth within certain limits of error except for fine-scale detail. That is, from some setsG it is possible to compute localized averages of the Earth structure at various depths. These localized averages will be slightly in error, and their errors will be larger as their resolving lengths are shortened. We show how to determine whether a given set G of measured gross Earth data permits such a construction of localized averages, and, if so, how to find the shortest length scale over which G gives a local average structure at a particular depth if the variance of the error in computing that local average from G is to be less than a specified amount. We apply the general theory to the linear problem of finding the depth variation of a frequency-independent local elastic dissipation ( Q ) from the observed damping rates of a finite number of normal modes. We also apply the theory to the nonlinear problem of finding density against depth from the total mass, moment and normal-mode frequencies, in case the compressional and shear velocities are known.
Mercury geochemistry of the Scioto River, Ohio: Impact of agriculture and urbanization

Abstract The Scioto River is a major tributary to the Ohio River, which runs from its headwaters in row crop dominated agricultural lands in central Ohio, south through the city of Columbus, the 15th largest city in the USA. During a high flow event in April 2004, water was collected from seven locations along the river, and analyzed for a number of chemical constituents including total and dissolved Hg. Total Hg concentration increased continually downstream with the highest concentrations found at Commercial Point, just below two large sewage treatment plants that serve metropolitan Columbus. The highest Cl− concentration was also found there. The highest NO 3 - concentrations were found in the agriculturally dominated portion of the river. The highest dissolved Hg concentration occurred in downtown Columbus. Using flow data from the day when the samples were collected, Hg yields were calculated at three locations within the basin: at Prospect in the northern, agriculture-dominated part of the basin; at Bellepoint located upstream of two reservoirs, just north of Columbus proper; and at downtown Columbus. The dissolved Hg yields in ng km−2 s−1 increased by a factor of 2 from Prospect to Bellepoint and then another 50% at Columbus. The particulate Hg yields increased only 10% from Prospect to Bellepoint, but 30% from Bellepoint to Columbus, with the particulate Hg yields about ∼2.5 to 4.5 times greater than the dissolved ones. These data suggest that yields of particulate Hg are affected more by urbanization than agricultural activities. The cause of the increasing yields of dissolved Hg as the river proceeded downstream is not clear at this time. It is assumed that the last increase is due to input from the urbanized portion of the watershed. As demonstrated previously, it appears that urbanized regions may retain a lower percentage of atmospherically deposited Hg than other landscape types.
Asymmetric Total Synthesis of Rhizoxin D.

We describe herein the synthesisof rhizoxin D by an approach utilizing catalytic asymmetricallylation as a key strategic element.The overall approach to this synthesis is illustrated inScheme 1 and relied upon disconnections at the C9yC10 andC20yC21 disubstituted alkenes to yield the three majorsubunits indicated. In the route described herein, both ofthese alkene linkages are established by a modified Julia–Lithgoe protocol developed previously in our laboratories,
An efficient synthesis of 5-azidotryptophan

Abstract An efficient synthesis of a potentially useful photoaffinity labeling reagent, 5-azidotryptophan, is described.
Progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) was a rare disease until the advent of the HIV/AIDS pandemic. Recent interest in the disorder has been spurred by its appearance in patients treated with the monoclonal antibodies natalizumab and rituximab. Unless the accompanying underlying immune deficit can be reversed, PML typically progresses to death fairly rapidly. Treatment directed against the JC virus has been unhelpful, but an increased understanding of disease pathogenesis may result in effective therapeutic strategies.
Thermomechanical buckling and postbuckling responses of composite panels with skewed stiffeners

Abstract The results of a detailed study of the buckling and postbuckling responses of composite panels with skewed stiffeners are presented. The panels are subjected to applied edge displacements and temperature changes. A first-order shear-deformation geometrically nonlinear shallow-shell theory that includes the effects of laminated anisotropic material behavior is used to model each section of the stiffeners and the skin. A mixed formulation is used in the analysis with the fundamental unknowns consisting of the generalized displacements and the stress resultants of the panel. The nonlinear displacements, strain energy, transverse shear stresses, transverse shear strain energy density, and their hierarchical sensitivity coefficients are evaluated. The hierarchical sensitivity coefficients measure the sensitivity of the buckling and postbuckling responses to variations in three sets of interrelated parameters; namely, the panel stiffnesses; the effective material properties of the individual layers; and the constituent material parameters (fibers, matrix, interface and interphase). Numerical results are presented for rectangular panels with open section I-stiffeners, subjected to edge shortening and uniform temperature change. The results show the effects of variations in the material properties of the skin and the stiffener on the buckling and postbuckling responses of the panel, as well as on the sensitivity coefficients.
Statistics and the Law

Mathematical models have found their way into our legal system as into most aspects of present-day life. For the most part the models to which we have recourse in the law are probabilistic, not deterministic. Great trial lawyers are masters of the subtleties of probability. Leibniz once remarked that jurists have practiced best of all mankind the art of logic in regard to contingencies [21]. Indeed, central to the question of the admissibility of evidence is its relevance, which the Federal Rules of Evidence define in terms of probability: Evidence is relevant if it has "[a]ny tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence" [14]. However, as we shall show, the intuition of attorneys and judges may need the guidance of an analysis relying on various statistical techniques. Some have recognized this need. Mr. Justice Holmes, writing in 1897, said: "For the rational study of the law,... the man of the future is the man of statistics" [20]. Courts have greeted offers of guidance in statistics with varying degrees of receptivity and skepticism. For example, in Alabama v. United States [1], the court said, "Statistics often tell much and Courts listen." On the other hand, in People v. Collins [25], the court cautioned, "Mathematics, a veritable sorcerer in our computerized society, while assisting the trier of fact in the search for truth, must not cast a spell over him." There are three general areas in which statistics is of assistance to the law: (1) in evidence, (2) as a model of the trial process itself, and (3) for support purposes. Poisson pioneered in the modeling of the trial process with his analysis of jury verdicts [27]; today some visionaries, critical of the delays and vagaries of our judicial system, propose that we replace judges or juries by computers properly programmed with all precedents, together with elaborately constructed probability-based decision rules. In support for the judicial process, statistical analyses have been done to decide whether pretrial conferences will reduce trial duration [15], whether pretrial detention increases the probability of conviction [23], or whether capital punishment is a deterrent to murder [6], [13]. It is with the use of statistics as evidence that we are concerned here. Some applications seem trivial; others have caused people to be imprisoned. One example of the former is interesting because it sheds some light on what probability one judge attached to "beyond a reasonable doubt." "Beyond a reasonable doubt" is the standard of proof for conviction in a criminal matter; most civil matters are decided on the basis of the preponderance of the evidence (although some cases such as fraud require the stricter standard of "clear and convincing evidence"). In a Swedish case [24] the defendant was charged with overtime
Future role of topotecan in the treatment of lung cancer.

Topotecan (HYCAMTIN®; GlaxoSmithKline, Brentford, Middlesex, UK) is a novel topoisomerase I inhibitor with potentially broad applicability in the treatment of solid and hematologic malignancies. In addition to its use in relapsed small-cell lung cancer (SCLC), topotecan is under investigation in numerous studies for first-line therapy in SCLC and for first- and second-line treatment of non-small-cell lung cancer (NSCLC). Preliminary evidence presented in this supplement demonstrates that single-agent topotecan and topotecan-based combination regimens are active in these settings. In addition to its potential use in SCLC and NSCLC, the feasibility and antitumor activity of topotecan as single-agent therapy and in combination therapy are under active investigation in a variety of other solid and hematologic tumors. Other important avenues of investigation include the feasibility and tumor activity of a more convenient oral formulation, as well as the investigation of alternate regimens (e.g., 3-day, weekly), with high priority given to regimen toxicity, patient convenience, and quality of life. Preliminary results of some of these trials are presented in this summary. The results of other clinical experience trials are eagerly anticipated.
Functional dissipation microarrays for classification

In this article, we describe a new method of extracting information from signals, called functional dissipation, that proves to be very effective for enhancing classification of high resolution, texture-rich data. Our algorithm bypasses to some extent the need to have very specialized feature extraction techniques, and can potentially be used as an intermediate, feature enhancement step in any classification scheme. Functional dissipation is based on signal transforms, but uses the transforms recursively to uncover new features. We generate a variety of masking functions and 'extract' features with several generalized matching pursuit iterations. In each iteration, the recursive process modifies several coefficients of the transformed signal with the largest absolute values according to the specific masking function; in this way the greedy pursuit is turned into a slow, controlled, dissipation of the structure of the signal that for some masking functions, enhances separation among classes. Our case study in this paper is the classification of crystallization patterns of amino acids solutions affected by the addition of small quantities of proteins.
Reaction of Hydrogen with Optical Defects in Glasses

A kinetic model for the removal of optical defects in glasses by exposure to hydrogen or deuterium gas is presented. Since annealing involves a chemical reaction at low temperatures, it is called “chemical annealing” to distinguish it from the common, higher-temperature, thermal annealing processes. As an example, this model is applied to the elimination of the aluminum/oxygen hole center in irradiated vitreous silica at 73°C in 93 kPa of D2.
Kähler manifolds with real holomorphic vector fields

For a Kahler manifold endowed with a weighted measure \(e^{-f}\,dv,\) the associated weighted Hodge Laplacian \(\Delta _{f}\) maps the space of \((p,q)\)-forms to itself if and only if the \((1,0)\)-part of the gradient vector field \(\nabla f\) is holomorphic. We use this fact to prove that for such \(f\), a finite energy \(f\)-harmonic function must be pluriharmonic. Motivated by this result, we verify that the same also holds true for \(f\)-harmonic maps into a strongly negatively curved manifold. Furthermore, we demonstrate that such \(f\)-harmonic maps must be constant if \(f\) has an isolated minimum point. In particular, this implies that for a compact Kahler manifold admitting such a function, there is no nontrivial homomorphism from its first fundamental group into that of a strongly negatively curved manifold.
Aircraft Anti-Icing and De-Icing Techniques and Modeling

Nomenclature Ac = accumulation parameter Cd drag coefficient Ci = lift coefficient Cm = moment coefficient Cp = pressure coefficient c = specific heat at constant pressure, J/(kg-K); airfoil chord, m D = propeller diameter, m; flexural stiffness, N-m D drag force, N d = droplet diameter, m E = total collection efficiency / = freezing fraction g = acceleration caused from gravity, m/s Hi = ice thickness, m Hp = plate thickness, m h = airfoil projected height, m hc = convective heat transfer coefficient, W/(m-K) hfg = heat of vaporization, J/kg hsi = heat of fusion, J/kg / = airfoil drag constant K = thermal conductivity, W/(m-K); inertia parameter K0 = modified inertia parameter k = roughness diameter, m LWC = liquid water content, kg/m M = local Mach number MVD = median volume droplet diameter, m m = mass, kg ra = mass flow rate, kg/s m' = mass flow rate per unit width, kg/(m-s) m" = mass flux, kg/(m-s) n = normal direction P = pressure, Pa p spatial pressure distribution, N/m <2 = heat rate, W q = normal pressure distribution, N/m
Synthetic magainin analogues with improved antimicrobial activity

Based on modifications to enhance the α-helical structure of the broad spectrum antibiotic magainin 2, a series of analogues have been synthesized which display an increase up to two orders of magnitude in antimicrobial activity and, in the most favorable case, no appreciable increase in hemolytic activity over magainin 1 at the concentrations tested.
Disk-based storage for scalable video

In this paper, we consider the placement of scalable video data on single and multiple disks for storage and real-time retrieval. For the single disk case, we extend the principle of constant frame grouping form CBR to VBR scalable video data. When the number of admitted users exceeds the server capacity, the rate of data sent to each user is reduced to relieve the disk system overload, offering a graceful degradation in comparison with nonscalable data. We examine the qualities of video reconstructions obtained from a real disk video server and find the scalable video more visually appealing. For the multiple disk scenario, we prove that periodic interlacing results in lower system delay than striping in a video server using round-robin scheduling. We verify the results through detailed simulation of a four- disk array.
Initiation of detonation by incident shock waves in hydrogen--oxygen--argon mixtures

Abstract A series of experiments was carried out to demonstrate in detail the steps by which a chemical reaction initiated by a shock wave couples to the wave. Shock speed, pressure, and heat transfer measurements gave complementary information on the process. The hydrogen-oxygen reaction that was studied is typical of many gaseous combustion reactions in having a temperature-dependent ignition induction time. Once reaction starts, energy is given to the incident shock wave so that induction times of successive elements of gas become shorter. During this period of decreasing induction time the shock wave is accelerated to a high transient value. Later the velocity falls off as the induction time reaches a short, constant interval and the reaction occurs close behind the shock wave.
Thrashing: its causes and prevention

A particularly troublesome phenomenon, thrashing, may seriously interfere with the performance of paged memory systems, reducing computing giants (Multics, IBM System 360, and others not necessarily excepted) to computing dwarfs. The term thrashing denotes excessive overhead and severe performance degradation or collapse caused by too much paging. Thrashing inevitably turns a shortage of memory space into a surplus of processor time.
Active esters in solid-phase peptide synthesis.

Incorporation of single amino acid residues into peptide chains built on insoluble polymeric supports a priori appeared promising: the use of isolated, well defined (and potentially commercially available) reactive intermediates were expected to reduce the extent of undesired side reactions. In spite of these expectations active esters were only infrequently used in solid-phase peptide synthesis, mainly because the reaction rates achieved with them were insufficient for rapid chain-lengthening that became possible with automated instruments. In recent years, however, a certain revival of the active ester principle can be noted. This is the consequence of two factors: the application of highly reactive esters and the discovery of efficient catalysts of the ester-aminolysis reaction. The mechanism of catalysis and its exploitation for further improvements are also discussed.
Microphysical modeling of Titan’s detached haze layer in a 3D GCM

Abstract We use a 3D GCM with coupled aerosol microphysics to investigate the formation and seasonal cycle of the detached haze layer in Titan’s upper atmosphere. The base of the detached haze layer is defined by a local minimum in the vertical extinction profile. The detached haze is seen at all latitudes including the south pole as seen in Cassini images from 2005–2012. The layer merges into the winter polar haze at high latitudes where the Hadley circulation carries the particles downward. The hemisphere in which the haze merges with the polar haze varies with season. We find that the base of the detached haze layer occurs where there is a near balance between vertical winds and particle fall velocities. Generally the vertical variation of particle concentration in the detached haze region is simply controlled by sedimentation, so the concentration and the extinction vary roughly in proportion to air density. This variation explains why the upper part of the main haze layer, and the bulk of the detached haze layer follow exponential profiles. However, the shape of the profile is modified in regions where the vertical wind velocity is comparable to the particle fall velocity. Our simulations closely match the period when the base of the detached layer in the tropics is observed to begin its seasonal drop in altitude, and the total range of the altitude drop. However, the simulations have the base of the detached layer about 100 km lower than observed, and the time for the base to descend is slower in the simulations than observed. These differences may point to the model having somewhat lower vertical winds than occur on Titan, or somewhat too large of particle sizes, or some combination of both. Our model is consistent with a dynamical origin for the detached haze rather than a chemical or microphysical one. This balance between the vertical wind and particle fall velocities occurs throughout the summer hemisphere and tropics. The particle concentration gradients that are established in the summer hemisphere are transported to the winter hemisphere by meridional winds from the overturning Hadley cell. Our model is consistent with the disappearance of the detached haze layer in early 2014. Our simulations predict the detached haze and gap will reemerge at its original high altitude between mid 2014 and early 2015.
THE FIRST VLBI DETECTION OF AN ULTRACOOL DWARF: IMPLICATIONS FOR THE DETECTABILITY OF SUB-STELLAR COMPANIONS

We present milliarcsecond-resolution radio very long baseline interferometry (VLBI) observations of the ultracool dwarfs TVLM 513-46546 (M8.5) and 2MASS J00361617+1821104 (L3.5) in an attempt to detect sub-stellar companions via direct imaging or reflex motion. Both objects are known radio emitters with strong evidence for periodic emission on timescales of about 2 hr and 3 hr, respectively. Using the inner seven VLBA antennas, we detect unresolved emission from TVLM 513-46546 on a scale of 2.5 mas (approx50 stellar radii), leading to a direct limit on the radio emission brightness temperature of T{sub B} approx> 4 x 10{sup 5} K. However, with the higher spatial resolution afforded by the full VLBA we find that the source appears to be marginally resolved at a low signal-to-noise ratio, possibly indicating that TVLM 513-46546 is a binary with a projected separation of approx1 mas (approx20 stellar radii). Using the 7 hr baseline of our observation, we find no astrometric shift in the position of TVLM 513-46546, with a 3sigma limit of about 0.6 mas. This is about three times larger than expected for an equal-mass companion with a few-hour orbital period. Future monitoring of its position on a range of timescales will provide the requiredmore » astrometric sensitivity to detect a planetary companion with a mass of approx10 M {sub J} in a approx>15 day (approx>0.06 AU) orbit, or with a mass of approx2 M {sub J} in an orbit of approx>0.5 yr (approx>0.3 AU).« less
A note on Hilbert schemes of nodal curves

Abstract We study the Hilbert scheme and punctual Hilbert scheme of a nodal curve, and the relative Hilbert scheme of a family of curves acquiring a node. The results are then extended to flag Hilbert schemes, parametrizing chains of subschemes. We find, notably, that if the total space X of a family X / B is smooth (over an algebraically closed field k ), then the relative Hilbert scheme Hilb m ( X / B ) is smooth over k and the flag Hilbert schemes are normal and locally complete intersection, but generally singular.
Reasoning about programs

Abstract This paper describes a theorem prover that embodies knowledge about programming constructs, such as numbers, arrays, lists, and expressions. The program can reason about these concepts and is used as part of a program verification system that uses the Floyd-Naur explication of program semantics. It is implemented in the qa 4 language; the qa 4 system allows many pieces of strategic knowledge, each expressed as a small program, to be coordinated so that a program stands forward when it is relevant to the problem at hand. The language allows clear, concise representation of this sort of knowledge. The qa 4 system also has special facilities for dealing with commutative functions, ordering relations, and equivalence relations; these features are heavily used in this deductive system. The program interrogates the user and asks his advice in the course of a proof. Verifications have been found for Hoare's FIND program, a real-number division algorithm, and some sort programs, as well as for many simpler algorithms. Additional theorems have been proved about a pattern matcher and a version of Robinson's unification algorithm. The appendix contains a complete, annotated listing of the deductive system and annotated traces of several of the deductions performed by the system.
The Science of Wound Bed Preparation

The concept of wound bed preparation (WBP) heralded a new era in terms of how we treat wounds. It emphasized the difference between acute and chronic wounds, and it cemented the idea that the processes involved in the healing of acute wounds do not apply completely to the healing of chronic wounds. The arbitrary division of the normal healing process into the phases of hemostasis, inflammation, proliferation, and maturation addresses the events in acute wound healing. We have realized that the impediments to healing in chronic wounds lead to a failure to progress through these phases and are independent factors that make the chronic wound a much more complex condition. A major advance in resolving or addressing the chronic wound has been the concept of WBP. WBP allows us to address the problems of wound healing individually the presence of necrotic tissue, hypoxia, high bacterial burden, corrupt matrix, and senescent cells within the wound bed. In WBP we can optimize our therapeutic agents to accelerate endogenous healing or to increase the effectiveness of advanced therapies.
Synthesis of Quaternary Carbon Stereogenic Centers through Enantioselective Cu-Catalyzed Allylic Substitutions with Vinylaluminum Reagents

Catalytic enantioselective allylic substitution (EAS) reactions, which involve the use of alkyl- or aryl-substituted vinylaluminum reagents and afford 1,4-dienes containing a quaternary carbon stereogenic center at their C-3 site, are disclosed. The C−C bond-forming transformations are promoted by 0.5−2.5 mol % of sulfonate bearing chiral bidentate N-heterocyclic carbene (NHC) complexes, furnishing the desired products efficiently (66−97% yield of isolated products) and in high site (>98% SN2′)- and enantioselectivity [up to 99:1 enantiomer ratio (er)]. To the best of our knowledge, the present report puts forward the first cases of allylic substitution reactions that result in the generation of all-carbon quaternary stereogenic centers through the addition of a vinyl unit. The aryl- and vinyl-substituted vinylaluminum reagents, which cannot be prepared in high efficiency through direct reaction with diisobutylaluminum hydride, are accessed through a recently introduced Ni-catalyzed reaction of the corres...
Exogenous shocks, contagion, and bank soundness: a macroeconomic framework

Abstract In a model where all banks are initially solvent, an exogenous shock affects confidence, causing a flight from deposits into domestic and foreign currency. Real interest rates increase unexpectedly, affecting firms and raising the share of the banks nonperforming assets. This contagion causes a bank run. Simulations show that compensatory monetary policy mitigates the bank run but causes macroeconomic imbalances. Combining compensatory monetary policy with tight fiscal policies slows the bank run and mitigates insolvency. A devaluation, combined with compensatory monetary policy, reduces insolvencies and increases the growth of real income, but at the cost of increased inflation.
Incomplete information and optimal market structure public purchases from private providers

Abstract Market structure is endogenized in a normative model of public procurement featuring a social cost of profit, product variety, economies of scale, and incomplete information about cost. Depending on parameters, either sole sourcing or dual sourcing might be optimal. However, if the social cost of profit is positive but not too large, incomplete information biases optimal market structure in favor of sole sourcing. On the other hand, this bias in favor of sole sourcing may be reversed if the social cost of profit is large. An application to the publicly financed treatment for drug abuse motivates the analysis.
Adaptations of the vestibular system to short and long-term exposures to altered gravity.

Long-term space flight creates unique environmental conditions to which the vestibular system must adapt for optimal survival of a given organism. The development and maintenance of vestibular connections are controlled by environmental gravitational stimulation as well as genetically controlled molecular interactions. This paper describes the effects of hypergravity on axonal growth and dendritic morphology, respectively. Two aspects of this vestibular adaptation are examined: (1) How does long-term exposure to hypergravity affect the development of vestibular axons? (2) How does short-term exposure to extremely rapid changes in gravity, such as those that occur during shuttle launch and landing, affect dendrites of the vestibulocerebellar system? To study the effects of longterm exposures to altered gravity, embryonic rats that developed in hypergravity were compared to microgravity-exposed and control rats. Examination of the vestibular projections from epithelia devoted to linear and angular acceleration revealed that the terminal fields segregate differently in rat embryos that gestated in each of the gravitational environments.To study the effects of short-term exposures to altered gravity, mice were exposed briefly to strong vestibular stimuli and the vestibulocerebellum was examined for any resulting morphological changes. My data show that these stimuli cause intense vestibular excitation of cerebellar Purkinje cells, which induce up-regulation of clathrin-mediated endocytosis and other morphological changes that are comparable to those seen in long-term depression. This system provides a basis for studying how the vestibular environment can modify cerebellar function, allowing animals to adapt to new environments.
Trapping and release of implanted D/H ions in fused silica

Elastic recoil detection techniques have been used to measure hydrogen isotope profiles in fused silica implanted with 20 keV H and/or D ions. Saturation is obtained for both H and D implantations at concentrations of 2.1 x 10/sup 21/ ions/cm/sup 3/, in good agreement with results of gas loading experiments. FTIR measurements indicate that most of the implanted H bonds in the form of OH. Theoretical analyses using the local mixing model (LMM) of H-trapping provide a good fit to the saturation behavior and subsequent H movement toward the surface. Isochronal annealing shows that both H and D are released in a single stage centered about 550/sup 0/C. The best theoretical fit is for a 1.9 eV H-trap activation energy.