cssi/SciSciGPT-SciSciNet huggingface dataset:
The geoid: Definition and determination

The determination of the geoid has been one of the prime goals of geodesy. Knowledge of geoid undulations with respect to some reference surface was needed for the determination of the figure of the earth, for the precise reduction of distance measurements to a reference ellipsoid, and for the determination of the geocentric location of points on the surface of the earth. Currently and in the future, undulation information can also be used in geophysical studies related to crustal structures and in oceanographic studies related to sea surface topography. The actual determination of global geoids has been carried out by using gravimetric data, satellite-derived information related to the gravitational field of the earth, or a combination of the two techniques. Regional geoid determinations have been made by astrogeodetic techniques. For some applications of undulation information, undulation standard deviations of the order of ±5 m would be sufficient. Such an accuracy can be obtained by using data currently available. In the past few years, renewed interest in the geoid arose when the concept of satellite altimetry was proposed to measure the distance from the satellite to some area on the ocean surface.
Control systems synthesis for a large flexible space antenna

Abstract The problem of control systems synthesis is considered for controlling the rigid-body attitude and elastic motion of a large deployable space-based antenna. Two methods for control systems synthesis are considered. The first method utilizes the stability and robustness properties of the controller consisting of torque actuators and collocated attitude and rate sensors. The second method is based on the linear-quadratic-Gaussian (LQG) control theory. A combination of the two methods, which results in a two-level hierarchical control system, is also briefly discussed. The performance of the controllers is analyzed by computing the variances of pointing errors, feed misalignment errors and surface contour errors in the presence of sensor and actuator noise.
Improved approximations of Poissonian errors for high confidence levels

We present improved numerical approximations to the exact Poissonian confidence limits for small numbers n of observed events following the approach of Gehrels. Analytic descriptions of all parameters used in the approximations are provided to allow their straightforward inclusion in computer algorithms for processing of large data sets. Our estimates of the upper (lower) Poisson confidence limits are accurate to better than 1 per cent for n ≤ 100 and values of S, the derived significance in units of Gaussian standard deviations, of up to 7 (5). In view of the slow convergence of the commonly used Gaussian approximations towards the correct Poissonian values, in particular for higher values of S, we argue that, for n ≤ 40, Poissonian statistics should be used in most applications, unless errors of the order of, or exceeding, 10 per cent are acceptable.
One-dimensional stability of AP deflagrations

A small-perturbation investigation of ammonium perchlorate deflagrations is made to determine the intrinsic stability of a one-dimensional burning configuration. It is found on the basis of a particular model of the flame structure that above a certain pressure, dependent upon the numerical values used, a stable one-dimensional flame cannot exist. Detailed calculations are presented for a preferred set of parameters, and the pressure above which stability is impossible is between 620 and 2140 psia, depending on whether the AP-gas interface is in equilibrium or is pyrolysis controlled.
Scaling of Structural Failure

This article attempts to review the progress achieved in the understanding of scaling and size ef­ fect in the failure of structures. Particular emphasis is placed on quasi brittle materials for which the size etTect is important and complicated. After reflections on the long history of size effect studies, attention is focused on three main types of size effects, namely the statistical size effect due to randomness of strength, the energy release size effect, and the possible size effect due to fractality of fracture or microcracks. Definitive conclusions on the applicability of these theories are drawn. Subsequently, the article discusses the application of the known size effect law for the measurement of material fracture properties, and the modeling of the size effect by the cohesive crack model, non local finite element models and discrete element models. Extensions to com­ pression failure and to the rate-dependent material behavior are also outlined. The damage con­ stitutive law needed for describing a microcracked material in the fracture process zone is dis­ cussed. Various applications to quasibrittle materials, including concrete, sea ice, fiber compos­ ites, rocks and ceramics are presented. There are 377 references included in this article.
Normal curvatures of asymptotically constant graphs and Carathéodory’s conjecture

We show that Caratheodory’s conjecture, on umbilical points of closed convex surfaces, may be reformulated in terms of the existence of at least one umbilic in the graphs of functions f : R → R whose gradient decays uniformly faster than 1/r. The divergence theorem then yields a pair of integral equations for the normal curvatures of these graphs, which establish some weaker forms of the conjecture. In particular, we show that there are uncountably many principal lines in the graph of f whose projection into R are parallel to any given direction.
Heterotic matrix string theory

Abstract M-theory suggests the large N limit of the matrix description of a collection of N Type IA D-particles should provide a nonperturbative formulation of heterotic string theory. In this paper states in the matrix theory corresponding to fundamental heterotic strings are identified, and their interactions are studied. Comments are made about analogous states in Type IIA string theory, which correspond to bound states of D-particles and D-eightbranes.
A lower bound for the canonical height on abelian varieties over abelian extensions

Let A be an abelian variety defined over a number field K and let ĥ be the canonical height function on A(K) attached to a symmetric ample line bundle L. We prove that there exists a constant C = C(A,K,L) > 0 such that ĥ(P ) ≥ C for all nontorsion points P ∈ A(K), where K is the maximal abelian extension of K.
Aqueous penetration of moxifloxacin 0.5% ophthalmic solution and besifloxacin 0.6% ophthalmic suspension in cataract surgery patients

Purpose To determine the aqueous humor concentrations of moxifloxacin and besifloxacin after routine preoperative topical dosing in patients having cataract surgery. Setting Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA. Methods In this prospective randomized parallel double-masked clinical trial, 1 drop of commercially available moxifloxacin 0.5% ophthalmic solution or besifloxacin 0.6% ophthalmic suspension was administered every 10 minutes for a total of 4 doses beginning 1 hour before routine cataract surgery. Aqueous humor was sampled via the paracentesis, and antibiotic concentrations were determined using validated high-performance liquid chromatography procedures. Results The study enrolled 50 patients. The aqueous concentration of the antibiotic agent was detectable in all 23 moxifloxacin samples and in 10 (40%) of the 25 besifloxacin samples ( P P P Conclusions After topical preoperative administration, moxifloxacin 0.5% ophthalmic solution had a 38-fold to 50-fold higher concentration in the aqueous humor than besifloxacin 0.6% ophthalmic suspension. Besifloxacin was undetectable in more than half the aqueous humor samples. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.
An alternative explanation for the resource curse: the income effect channel

This article provides an alternative explanation for the ‘resource curse’ based on the income effect resulting from high government current spending in resource rich economies. Using a simple life cycle framework, we show that private investment in the nonresource sector is adversely affected if private agents expect extra government current spending financed through resource sector revenues in the future. This income channel of the resource curse is stronger for countries with lower degrees of openness and forward altruism. We empirically validate these findings by estimating nonhydrocarbon sector growth regressions using a panel of 25 oil-exporting countries over the period 1992 to 2005.
On Dehn Functions of Infinite Presentations of Groups

We introduce two new types of Dehn functions of group presentations which seem more suitable (than the standard Dehn function) for infinite group presentations and prove the fundamental equivalence between the solvability of the word problem for a group presentation defined by a decidable set of defining words and the property of being computable for one of the newly introduced functions (this equivalence fails for the standard Dehn function). Elaborating on this equivalence and making use of this function, we obtain a characterization of finitely generated groups for which the word problem can be solved in nondeterministic polynomial time.
Intramolecular Povarov reactions involving 3-aminocoumarins.

A series of pentacyclic heterocyclic systems (15 examples, 69–89%) have been synthesized using intramolecular Povarov reactions involving 3-aminocoumarins and O-cinnamylsalicylaldehydes. The Povarov adducts are formed with high selectivity for the trans,trans relative stereochemistry in the newly-formed [6,6] fused ring system. One example of a Povarov adduct featuring a new [6,5] fused ring system is reported. In this case, cis,trans relative stereochemistry was preferred.
Using gauge coupling unification and proton decay to test minimal supersymmetric SU (5)

Abstract We derive a one-loop expression, including all thresholds, for the mass of the proton decay mediating color triplets M D c , in minimal supersymmetric SU (5). The result for M D c does not depend on other heavy thresholds or extra representations with SU (5) invariant masses which might be added to the minimal model. We numerically correct our result to two-loop accuracy. Choosing inputs to maximize M D c and τ P , within experimental limits on the inputs and a 1 TeV naturalness bound, we derive a strict bound α 3 > 0.117. We discuss how this bound will change as experimental limits improve. Measurements of α 3 from deep inelastic scattering and the charmonium spectrum are below the bound α 3 > 0.117 by more than 3σ. We briefly review several ideas of how to resolve the discrepancy between these low values of α 3 and the determinations of α 3 from LEP event shapes.
Counting Maximal Antichains and Independent Sets

Answering several questions of Duffus, Frankl and Rodl, we give asymptotics for the logarithms of (i) the number of maximal antichains in the n-dimensional Boolean algebra and (ii) the numbers of maximal independent sets in the covering graph of the n-dimensional hypercube and certain natural subgraphs thereof. The results in (ii) are implied by more general upper bounds on the numbers of maximal independent sets in regular and biregular graphs. We also mention some stronger possibilities involving actual rather than logarithmic asymptotics.
An efficient synthesis of (-)-dodecahydro-3a,6,6,9a-tetramethylnaphtho[2,1-b]furan from (-)-sclareol

Abstract The title compound 1 was prepared in 74% overall yield (3 steps) from sclareol 2 . The key step involves osmium tetroxide catalysed rearrangement to 4a and b during the oxidative degradation of sclareol.
Hidden exceptional global symmetries in 4d CFTs

We study four dimensional = 1 gauge theories that arise on the worldvolume of D3-branes probing complex cones over del Pezzo surfaces. Global symmetries of the gauge theories are made explicit by using a correspondence between bifundamental fields in the quivers and divisors in the underlying geometry. These global symmetries are hidden, being unbroken when all inverse gauge couplings of the quiver theory vanish. In the broken phase, for finite gauge couplings, only the Cartan subalgebra is manifest as a global symmetry. Superpotentials for these models are constructed using global symmetry invariants as their building blocks. Higgsings connecting theories for different del Pezzos are immediately identified by performing the appropriate higgsing of the global symmetry groups. The symmetric properties of the quivers are also exploited to count the first few dibaryon operators in the gauge theories, matching their enumeration in the AdS duals.
Drops settling in sharp stratification with and without Marangoni effects

We present numerical simulations of drops settling in a layered ambient fluid. We focus on nearly spherical drops with Reynolds numbers of order 10. The ambient is composed of miscible fluids, with the top layer lighter than the lower one, representing fluid stratified through temperature or salinity variations, while the drop itself is heavier than both layers. The surface tension between the ambient and the drop may or may not be different for each layer. Such a system can be used to model oil droplets settling or rising in the ocean. When surface tension is uniform, the drop slows down significantly as it encounters the transition region, due to entrained fluid from the upper layer, before accelerating again in the lower layer. We characterize this effect in terms of the sharpness of the transition, and the drop's Reynolds number. When the upper and lower surface tensions are not matched, the drop may either suddenly accelerate through the transition region if the lower surface tension is less than the upper one, or be prevented from crossing into the lower layer if the lower surface tension is larger than the upper one. We focus on the drop's speed across the transition, and determine the conditions under which a drop may remain suspended at the transition region.
Kinetic phase transition in a one component irreversible reaction model

Irreversible many particle dynamical systems are relevant to a broad scope of phenomena in physics, chemistry and biology. We present a study of an irreversible kinetic reaction model for a one component autocatalytic reaction A + A → A2. The system is updated as follows: if an atom adsorbed on a lattice has any neighbors it reacts with one of them with a probability (1 - p), and the two atoms leave the lattice, else the atom remains adsorbed. As p is varied, the adsorbed atoms undergo a second order kinetic phase transition from a chemically active partially covered state to a completely covered state which corresponds to the "poisoning" phenomenon seen on catalysts. The transition is studied both numerically and theoretically to gain more understanding of kinetic phase transitions and to find new methods to describe them. Finite size scaling analysis of the critical behavior has been carried out, and critical and dynamical exponents are found. The critical exponents are found to be consistent with the critical exponents in the Reggeon field theory/directed percolation universality class.
Effects of Cooling and Star Formation on the Baryon Fractions in Clusters

We study the effects of radiative cooling and galaxy formation on the baryon fractions in clusters using high-resolution cosmological simulations that resolve formation of cluster galaxies. The simulations of nine individual clusters spanning a decade in mass are performed with the shock-capturing Eulerian adaptive mesh refinement N-body+gasdynamical Adaptive Refinement Tree code. For each cluster the simulations were done in the adiabatic regime (without dissipation) and with radiative cooling and several physical processes critical to various aspects of galaxy formation: star formation, metal enrichment, and stellar feedback. We show that radiative cooling of gas and associated star formation increase the total baryon fractions within radii as large as the virial radius. The effect is strongest within cluster cores, where the simulations with cooling have baryon fractions larger than the universal value, in contrast to the adiabatic simulations in which the fraction of baryons is substantially smaller than the universal value. At larger radii (r r500) the cumulative baryon fractions in simulations with cooling are close to the universal value. The gas fractions in simulations with dissipation are reduced by ≈20%-40% at r < 0.3rvir and ≈10% at larger radii compared to the adiabatic runs, because a fraction of gas is converted into stars. There is an indication that gas fractions within different radii increase with increasing cluster mass as fgas ∝ M. We find that the total baryon fraction within the cluster virial radius does not evolve with time in both adiabatic simulations and in simulations with cooling. The gas fractions in the latter decrease slightly from z = 1 to 0 due to ongoing star formation. Finally, to evaluate systematic uncertainties in the baryon fraction in cosmological simulations we present a comparison of gas fractions in our adiabatic simulations to resimulations of the same objects with the entropy-conserving smoothed particle hydrodynamics (SPH) code Gadget. The cumulative gas fraction profiles in the two sets of simulations on average agree to better than ≈3% outside the cluster core (r/rvir 0.2) but differ by up to 10% at small radii. The differences are smaller than those found in previous comparisons of Eulerian and SPH simulations. Nevertheless, they are systematic and have to be kept in mind when using gas fractions from cosmological simulations.
Quantification of F2-isoprostanes as a reliable index of oxidative stress in vivo using gas chromatography-mass spectrometry (GC-MS) method.

Abstract Free radical-induced lipid peroxidation has been implicated in a number of human diseases including atherosclerosis, cancer, and neurodegenerative diseases. F2-Isoprostanes (IsoPs) are isomers of prostaglandin PGF2α that are generated in vivo from the free radical-initiated peroxidation of arachidonic acid independent of cyclooxygenase enzymes. Since the discovery of the IsoPs in the early 1990s, a large body of evidence has been accumulated to indicate that quantification of these F2-IsoPs represents the most reliable biomarker to assess oxidative stress in vivo. A variety of analytical approaches have been developed for the quantification of these novel compounds; these methods include mass spectrometry (MS) detection coupled to gas chromatography (GC) or liquid chromatography (LC) separation, and detection using immunological approaches. This article summarizes our current methodology to quantify F2-IsoPs in biological fluids and tissues using GC-MS. This method includes solid-phase extraction (SPE), thin-layer chromatography (TLC) purification, chemical derivatization, and MS detection using negative ion chemical ionization (NICI) coupled with GC. The protocol described herein has been optimized and validated to provide the best sensitivity and selectivity for quantification of F2-IsoPs from a variety of biological sources.
On the ideal of the shortest vectors in the Leech lattice and other lattices

Let $$X \subset {\mathbb R}^m$$X?Rm be a spherical code (i.e., a finite subset of the unit sphere) and consider the ideal of all polynomials in $$m$$m variables which vanish on $$X$$X. Motivated by a study of cometric ($$Q$$Q-polynomial) association schemes and spherical designs, we wish to determine certain properties of this ideal. After presenting some background material and preliminary results, we consider the case where $$X$$X is the set of shortest vectors of one of the exceptional lattices $$E_6$$E6, $$E_7$$E7, $$E_8$$E8, $$\Lambda _{{24}}$$?24 (the Leech lattice) and determine for each: (i) the smallest degree of a non-trivial polynomial in the ideal and (ii) the smallest $$k$$k for which the ideal admits a generating set of polynomials all of degree $$k$$k or less. As it turns out, in all four cases mentioned above, these two values coincide, as they also do for the icosahedron, our introductory example. The paper concludes with a discussion of these two parameters, two open problems regarding their equality and a few remarks concerning connections to cometric association schemes.
Psychoanalysis and the Spirit of Capitalism

In 1904–?5, Max Weber famously argued that Calvinism had supplied early capitalism with a “spirit” (geist) without which such capitalist virtues as methodical devotion to task would not have developed. More recently Luc Boltanski and Eve Chiapello in Le Nouvel Espirit de Capitalisme have argued that capitalism always has a spirit (esprit), and have traced in outline the history of the spirit of capitalism for the last one hundred years. In my paper I will modify their work to argue that psychoanalysis made a crucial contribution to the spirit of the second industrial revolution (mass production and mass consumption), a contribution that helped reorient modern capitalism toward its contemporary, consumerist direction. This reorientation, I suggest, reflected a fundamental change in the character of the family: the rise of modern personal life. This change, moreover, cannot be understood through sociological means alone since it involved unconscious or deep psychological changes in modern character structure. Highly ambiguous, we are still grappling with its implications.
The Spectral Evolution of Transient Anomalous X-Ray Pulsar XTE J1810-197

We present a multiepoch spectral study of the transient anomalous X-ray pulsar XTE J1810-197 obtained with the X-Ray Multi-Mirror Mission (XMM-Newton). Four observations taken over the course of a year reveal strong spectral evolution as the source fades from outburst. The origin of this is traced to the individual decay rates of the pulsar's spectral components. A two-temperature fit at each epoch requires that the temperatures remain nearly constant at kT1 = 0.25 keV and kT2 = 0.67 keV, while the luminosities of these components decrease exponentially with τ1 = 900 and τ2 = 300 days, respectively. The integrated outburst energy is E1 = 1.3 × 1042d ergs and E2 = 3.9 × 1042d ergs for the two spectral components, respectively. One possible interpretation of the XMM-Newton observations is that the slowly decaying cooler component is the radiation from a deep heating event that affected a large fraction of the crust, while the hotter component is powered by external surface heating at the footpoints of twisted magnetic field lines by magnetospheric currents that are decaying more rapidly. The energy-dependent pulse profile of XTE J1810-197 is well modeled at all epochs by the sum of a broad pulse that dominates in the soft X-rays and a narrower one at higher energies. These profiles peak at the same phase, suggesting a concentric emission geometry on the neutron star surface. The spectral and pulse evolution together argue against the presence of a significant "power-law" contribution to the X-ray spectrum below 8 keV. The extrapolated flux is projected to return to the historic quiescent level, characterized by an even cooler blackbody spectrum, by the year 2007.
Controllability and observability of flexible structures with proof-mass actuators

Relationships between Hankel singular values of a structure with a proof-mass actuator to those of a structure with an ideal actuator are analyzed. They indicate that the proof-mass actuator has little influence on Hankel singular values of a structure if the natural frequency of the actuator is much lower than the structural frequencies. This fact significantly simplifies controllability/observability analysis and model reduction of flexible structures. Results from numerical simulations verify the conclusions.
Adaptive Optimal Stochastic State Feedback Control of Resistive Wall Modes in Tokamaks

An adaptive optimal stochastic state feedback control is developed to stabilize the resistive wall mode (RWM) instability in tokamaks. The extended least square method with exponential forgetting factor and covariance resetting is used to identify the time-varying stochastic system model. A Kalman filter is used to estimate the system states. The estimated system states are passed on to an optimal state feedback controller to construct control inputs. The Kalman filter and the optimal state feedback controller are periodically redesigned online based on the identified system model. This adaptive controller can stabilize the time dependent RWM in a slowly evolving tokamak discharge. This is accomplished within a time delay of roughly four times the inverse of the growth rate for the time-invariant model used.
Trans-Z-Source Inverters

This paper extends the impedance-source (Z-source) inverters concept to the transformer-based Z-source (trans-Z-source) inverters. The original Z-source inverter (ZSI) employs an impedance network of two inductors and two capacitors connected in a special arrangement to interface the dc source and the inverter bridge. It has buck and boost function that cannot be achieved by traditional voltage-source inverters and current-source inverters. In the proposed four trans-Z-source inverters, all the impedance networks consist of a transformer and one capacitor. While maintaining the main features of the previously presented Z-source network, the new networks exhibit some unique advantages, such as the increased voltage gain and reduced voltage stress in the voltage-fed trans-ZSIs and the expanded motoring operation range in the current-fed trans-ZSIs, when the turns ratio of the transformer windings is over 1. Simulation and experimental results of the voltage-fed and the current-fed trans-ZSIs are provided to verify the analysis.
Rotational Evolution during Type I X-Ray Bursts

The rotation rates of six weakly magnetic neutron stars accreting in low-mass X-ray binaries have most likely been measured by Type I X-ray burst observations with the Rossi X-Ray Timing Explorer Proportional Counter Array. The phenomenology of the nearly coherent oscillations detected during the few seconds of thermonuclear burning is most simply understood as rotational modulation of brightness asymmetries on the neutron star surface. We show that, as suggested by Strohmayer and colleagues, the frequency changes of 1-2 Hz observed during bursts are consistent with angular momentum conservation as the burning shell hydrostatically expands and contracts during the burst. We calculate how vertical heat propagation through the radiative outer layers of the atmosphere and convection affect the coherence of the oscillation. We show that the evolution and coherence of the rotational profile depends strongly on whether the burning layers are composed of pure helium or mixed hydrogen/helium. Our results help explain the absence (presence) of oscillations from hydrogen-burning (helium-rich) bursts that was found by Muno and collaborators. We also investigate angular momentum transport within the burning layers and address the recoupling of the burning layers with the star. We show that the Kelvin-Helmholtz instability is quenched by the strong stratification, and that mixing between the burning fuel and underlying ashes by the baroclinic instability does not occur. However, the baroclinic instability may have time to operate within the differentially rotating burning layer.
Consistent Estimates of the Elasticity of Substitution between Land and Non-Land Inputs in the Production of Housing☆

Abstract This paper reports new estimates of the elasticity of substitution between land and non-land inputs in the production of housing. Errors in the measurement of land value may have biased existing estimates of the substitution elasticity downward, leading to the conclusion that the substitution elasticity is less than one. The data analyzed in this study consist of observations on the transaction prices of both the lot and the house, obtained by tracking the development of residential subdivisions. The results indicate that the substitution elasticity is higher than indicated in previous studies, and may not differ significantly from one.
A Gallium Nitride Switched-Capacitor Circuit Using Synchronous Rectification

The physical characteristics of gallium nitride (GaN) make it theoretically superior to silicon (Si) in such aspects as the temperature of operation, switching speed, breakdown voltage, and efficiency. While much research has been conducted on GaN devices, the discussion of third-quadrant operation is limited. Furthermore, the merits of GaN transistors, particularly their fast switching speed and low on-resistance, make them suitable for switched-capacitor circuits. This paper demonstrates the ability of a GaN transistor to function as a synchronous rectifier in a switched-capacitor circuit. A 500 W GaN-based voltage doubler capable of achieving zero-current switching is presented with supporting experimental results. This circuit achieves peak efficiencies of 97.6% and 96.6% while switching at frequencies of 382 and 893 kHz, respectively.
Functions on the zeroes of dx

Abstract In the model F of synthetic differential geometry consisting of sheaves (with respect to open covers) over F , the opposite category of the category of closed finitely generated C ∞ -rings, any morphism from S , the zeroes of the “amazing right adjoint” of d x , to the real line R extends to a morphism from R to R . This shows that the De Rham cohomology of the space S is the same as the characteristic cohomology of the ideal generated by d x .
Investigations into transition-metal-catalyzed arene trifluoromethylation reactions

Trifluoromethyl-substituted arenes and heteroarenes are widely prevalent in pharmaceuticals and agrochemicals. As a result, the development of practical methods for the formation of aryl–CF3 bonds has become an active field of research. Over the past five years, transition-metal-catalyzed cross-coupling between aryl–X (X = halide, organometallic, or H) and various ‘CF3’ reagents has emerged as a particularly attractive approach to generating aryl–CF3 bonds. Despite many recent advances in this area, current methods generally suffer from limitations such as poor generality, harsh reaction conditions, the requirement for stoichiometric quantities of metals, and/or the use of costly CF3 sources. This Account describes our recent efforts to address some of these challenges by: (1) developing aryltrifluoromethylation reactions involving high oxidation state Pd intermediates, (2) exploiting AgCF3 for C–H trifluoromethylation, and (3) achieving Cu-catalyzed trifluoromethylation with photogenerated CF3 •. 1 Introduction 2 Part 1. Aryltrifluoromethylation via High-Valent Palladium 3 Part 2. Aryltrifluoromethylation Using AgCF3 4 Part 3. Cu-Catalyzed Aryltrifluoromethylation with CF3• 5 Outlook
Introduction to the Special Issue on the Practical Salinity Scale 1978

This paper outlines the work done at the five laboratories which provided, at the request of the Joint Panel on Oceanographic Tables and Standards (JPOTS), the basic data for the new Practical Salinity Scale 1978, Interlaboratory agreement of a very high order was achieved. The new scale is in process of acceptance by all major oceanographic societies, at which time it will be officially recommended for all future reporting of oceanographic data.
A Robust Classification of Galaxy Spectra: Dealing with Noisy and Incomplete Data

Over the next few years new spectroscopic surveys (from the optical surveys of the Sloan Digital Sky Survey and the 2dF Galaxy Survey through to space-based ultraviolet satellites such as GALEX) will provide the opportunity and challenge of understanding how galaxies of different spectral type evolve with redshift. Techniques have been developed to classify galaxies based on their continuum and line spectra. Some of the most promising of these have used the Karhunen & Loeve transform (or principal component analysis) to separate galaxies into distinct classes. Their limitation has been that they assume that the spectral coverage and quality of the spectra are constant for all galaxies within a given sample. In this paper we develop a general formalism that accounts for the missing data within the observed spectra (such as the removal of sky lines or the effect of sampling different intrinsic rest-wavelength ranges due to the redshift of a galaxy). We demonstrate that by correcting for these gaps we can recover an almost redshift-independent classification scheme. From this classification we can derive an optimal interpolation that reconstructs the underlying galaxy spectral energy distributions in the regions of missing data. This provides a simple and effective mechanism for building galaxy spectral energy distributions directly from data that may be noisy, incomplete, or drawn from a number of different sources.
Galactic Positron Annihilation Radiation

Recent observations suggest that galactic line emission at 511 keV results from the superposition of contributions from a variable, compact source and an interstellar distribution of positrons resulting from the decay of radionuclei produced by thermonuclear burning supernovae. The compact point source could have turned on as recently as 1977 and has not been seen since 1979. Photon‐photon pair production in the vicinity of a relatively small black hole (<103 M⊙) could be the source of the annihilating positrons in the point source. It is not known whether this compact object lies exactly at the Galactic Center.
The results of medical treatment of peptic ulcer.

Abstract The results of conservative therapy in gastric and duodenal ulcer, as observed at the Presbyterian Hospital over a period of years, have been summarized. The average healing time of gastric ulcer, and probably also of duodenal ulcer, is approximately six to seven weeks. The basis for symptomatic intractability or delayed healing is often difficult to evaluate, although emotional factors may play a role. In general, the immediate results of medical therapy for uncomplicated gastric or duodenal ulcer are satisfactory. After healing of the lesion, medical management probably has little influence on the natural course of the disease. The majority of patients ultimately experience recurrences. The recurrence rate in this series of patients has approximated once every two years in both gastric and duodenal ulcer. The long-term outlook is largely unpredictable in a given patient. However, a slow initial symptomatic response to therapy is a bad prognostic sign. The risk of recurrent hemorrhage following an initial bleeding episode was about once every six years in this series. After a second hemorrhage, the subsequent risk of bleeding was almost doubled. It appears that a tendency to hemorrhage is an anatomic accident attributable to the location of the ulcer. The development of a gastric carcinoma was observed in five of 101 patients with evidence of benign gastric ulcer who were followed on conservative therapy.
Commonality in the determinants of expected stock returns

Abstract We find that the determinants of the cross-section of expected stock returns are stable in their identity and influence from period to period and from country to country. Out-of-sample predictions of expected return are strongly and consistently accurate. Two findings distinguish this paper from others in the contemporary literature: First, stocks with higher expected and realized rates of return are unambiguously lower in risk than stocks with lower returns. Second, the important determinants of expected stock returns are strikingly common to the major equity markets of the world. Overall, the results seem to reveal a major failure in the Efficient Markets Hypothesis.
A prospective investigation of pulmonary embolism in women and men

Objective. —The aim of this study was to compare, in women and men suspected of pulmonary embolism, the frequency, risk factors, diagnosis, and presentation of pulmonary embolism as well as the accuracy of the ventilation/ perfusion scan (V/Q scan) as a diagnostic tool. Design. —Data were collected during a prospective study (the Prospective Investigation of Pulmonary Embolism Diagnosis) to establish the accuracy of the V/Q scan compared with pulmonary angiograms. Setting. —Six tertiary medical centers in Massachusetts, Michigan, Connecticut, Pennsylvania, and North Carolina. Participants. —Patients suspected of pulmonary embolism for whom a request was made for a V/Q scan or pulmonary angiogram (496 women and 406 men). Results. —Women 50 years old and under had a decreased frequency of pulmonary embolism compared with men of that age (16% vs 32%), but there was no difference in patients over 50 years old (Breslow-Day test, P P Conclusion. —Women 50 years old and under (even young women using oral contraceptives) who were suspected of having pulmonary emboli and were enrolled in the Prospective Investigation of Pulmonary Embolism Diagnosis study had a smaller frequency of pulmonary embolism than men of that age, The risk factors for pulmonary embolism were the same for women and men, except that women using oral contraceptives had an increased risk of pulmonary embolism following surgery. Although the V/Q scan was a useful tool in the preliminary evaluation for pulmonary embolism in these women, a pulmonary angiogram was often needed for accurate diagnosis. ( JAMA . 1992;268:1689-1696)
Outer bounds for the interference channel with a cognitive relay

In this paper, we first present an outer bound for a general interference channel with a cognitive relay, i.e., a relay that has non-causal knowledge of both independent messages transmitted in the interference channel. This outer bound reduces to the capacity region of the deterministic broadcast channel and of the deterministic cognitive interference channel the through nulling of certain channel inputs. It does not, however, reduce to that of certain deterministic interference channels for which capacity is known. As such, we subsequently tighten the bound for channels whose outputs satisfy an “invertibility” condition. This second outer bound now reduces to the capacity of the special class of deterministic interference channels for which capacity is known. The second outer bound is further tightened for the high-SNR deterministic approximation of the Gaussian channel by exploiting the special structure of the interference. We provide an example that suggests that this third bound is tight in at least some parameter regimes for the high-SNR deterministic approximation of the Gaussian channel. Another example shows that the third bound is capacity in the special case where there are no direct links between the non-cognitive transmitters.
Probing mechanical and chemical instabilities in neutron-rich matter

Abstract The isospin-dependence of mechanical and chemical instabilities is investigated within a thermal and nuclear transport model using a Skyrme-type phenomenological equation of state for neutron-rich matter. Respective roles of the nuclear mean field and the two-body stochastic scattering on the evolution of density and isospin fluctuations in either mechanically or chemically unstable regions of neutron-rich matter are investigated. It is found that the mean field dominates overwhelmingly the fast growth of both fluctuations, while the two-body scattering influences significantly the later growth of the isospin fluctuation only. The magnitude of both fluctuations decreases with the increasing isospin asymmetry because of the larger reduction of the attractive isoscalar mean field by the stronger repulsive neutron symmetry potential in the more neutron-rich matter. Moreover, it is shown that the isospin fractionation happens later, but grows faster in the more neutron-rich matter. Implications of these results to current experiments exploring properties of neutron-rich matter are discussed.
Statistical Inference on Errorfully Observed Graphs

Statistical inference on graphs is a burgeoning field in the applied and theoretical statistics communities, as well as throughout the wider world of science, engineering, business, etc. In many applications, we are faced with the reality of errorfully observed graphs. That is, the existence of an edge between two vertices is based on some imperfect assessment. In this article, we consider a graph G = (V, E). We wish to perform an inference task—the inference task considered here is “vertex classification,” that is, given a vertex v with unknown label Y(v), we want to infer the label for v based on the graph G and the given labels for some set of vertices in G not containing v. However, we do not observe G; rather, for each potential edge uv∈(V2) we observe an “edge feature” that we use to classify uv as edge/not-edge. Thus, we errorfully observe G when we observe the graph G˜=(V,E˜) as the edges in E˜ arise from the classifications of the “edge features,” and are expected to be errorful. Moreover, we fac...
Cooperative Topology Control with Adaptation for improved lifetime in wireless sensor networks

Topology control algorithms allow each node in a wireless multi-hop network to adjust the power at which it makes its transmissions and choose the set of neighbors with which it communicates directly, while preserving global goals such as connectivity or coverage. This allows each node to conserve energy and contribute to increasing the lifetime of the network. In this paper, we consider (i) both the energy costs of communication as well as the amount of available energy at each node, (ii) the realistic situation of varying rates of energy consumption at different nodes, and (iii) the fact that co-operation between nodes, where some nodes make a sacrifice by increasing energy consumption to help other nodes reduce their consumption, can be used to extend network lifetime. This paper introduces a new distributed topology control algorithm, called the Cooperative Topology Control with Adaptation (CTCA), based on a game-theoretic approach that maps the problem of maximizing the network's lifetime into an ordinal potential game. We prove the existence of a Nash equilibrium for the game. Our simulation results indicate that the CTCA algorithm extends the life of a network by more than 50% compared to other algorithms. We also study the performance of the distributed CTCA algorithm in comparison to an optimal centralized algorithm as a function of the communication ranges of nodes and node density.
Titanium-mediated olefinations of cyclobutenedione derivatives

Abstract A variety of cyclobutenedione derivatives, including squaric esters, react with dimethyl titanocene to afford the corresponding methylenation products. With certain mixed-substituted substrates the reaction proceeds preferably at a ketonic carbonyl rather than a vinylogous ester.
Structure-based design and synthesis of a series of hydroxamic acids with a quaternary-hydroxy group in P1 as inhibitors of matrix metalloproteinases.

Abstract Examination of the S1 area of the active site of pro-stromelysin has led us to the design of novel and potent inhibitors of matrix metalloproteinases containing constrained quaternary-hydroxy group at P1. The synthesis and biological activity of these compounds with variations at P1′, P2′, and P3′, will be described.
Significantly increased cycling performance of novel “self-matrix” NiSnO3 anode in lithium ion battery application

A novel nickel tin oxide (NiSnO3) was reported to be used as an anode for lithium ion batteries. It was found that NiSnO3 shows higher cycling performance than the mixture of NiO and SnO2 with the same elemental composition, and the reversible capacity retention is 57% and 32% after 100 charge/discharge cycles, respectively. The NiSnO3 anode can be electrochemically decomposed into NiO, Sn and Li2O in the first discharge process. NiO and Sn can significantly function as “self-matrices” for each other besides the formed Li2O matrix. The massive matrices effectively buffer the large volume change and prevent the aggregation of the nanosized particle upon cycling, resulting in the improved cycling performance without sacrificing the specific energy capacity.
Optimal "work-up" of stillbirth: evidence!

o c t s r p r s a S tillbirth is one of the most devastating, as well as common, obstetric complications, affecting over 3 million pregnancies per year throughout the world. Definitions of stillbirth (and thus stillbirth rates) vary in different countries, based on gestational age. In the United States, stillbirth (defined as fetal death at 20 weeks’ gestation) affects about 1 in 160 pregnancies (6-7 per 1000 births). The rate is similar in most highincome countries (3-5 per 1000 births), but is considerably higher (20-100 per 1000 births) in lowand middle-income countries. A recent series published in the Lancet underscored the relative lack of attention and research funding stillbirth has received, as well as suggestions for reducing the rate of stillbirth. A major unanswered question is the optimal diagnostic evaluation for cases of stillbirth. Indeed, the optimal evaluation for stillbirth remains controversial and there are few data with which to guide clinicians. There are several reasons why it can be difficult to ascertain a “cause” of stillbirth. First, the cause of stillbirth may be complex and multifactorial. Several conditions simultaneously occurring may contribute to a given stillbirth and it may not be possible to determine a single proximate cause. Second, many conditions are “risk factors” rather than causes of stillbirth. These conditions are often present in pregnancies with live births. Examples include smoking, obesity, or well-controlled diabetes. Third, a cause of death may not be identified, even after a thorough evaluation of stillbirth. Finally, there are likely causes of stillbirth that have yet to be discovered. There are also several nonmedical issues that influence the diagnostic “workup” of stillbirths. Cost is a major concern and in many countries, patients and health care systems cannot or will not pay for all of the tests that may potentially be useful in the evaluation of stillbirths. In addition, emotional and cultural factors may influence a family’s willingness to permit a stillbirth investigation. Parents may believe that a “workup” will not change anything or they may be angry at the medical system as the bearer of bad news. Also, families may have reservations about autopsy because of religious beliefs or misconceptions about what actually takes place. In this issue of the American Journal of Obstetrics and Gynecology, Korteweg and colleagues present data suggesting that
Hierarchical functional layers on high-capacity lithium-excess cathodes for superior lithium ion batteries

Abstract Li-excess layered Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 (LMNCO) nanoparticles are facilely synthesized using a surfactant-assisted dispersion method. Ultrathin and conformal oxide coatings are deposited on the surface of individual LMNCO nanoparticle via atomic layer deposition (ALD). The effect of oxide ALD coatings on improving electrochemical performance of LMNCO electrodes is evaluated and optimized via tuning the coating thickness and composition. In addition, we synthesize a novel core–shell structure cathode consisting of Li-excess LMNCO as core and Li-stoichiometric material as shell, and its electrochemical property is optimized by tailoring weight content and composition of shell materials. Finally, electrochemical performance of Li-excess cathode material can be maximized by surface modification with hierarch functional layers composed of 10 wt.% LiCoO 2 shell (∼10 nm thick) and 6ZrO 2 ALD layers (∼1 nm thick), which delivers very high initial discharge capacities of 296.4, 259.8, 156.6 and 104.2 mAh g −1 at 0.1 C , 1 C , 5 C and 10 C , and can retain 184.0 mAh g −1 at 1 C after 100 electrochemical cycles. Such remarkably improved cycleabilitiy and rate capability of nanoarchitected Li-excess layered cathode material can be attributed to the synergic effect from hierarchical functional coatings to reduce electrochemical polarization, structural degradation and side reactions during electrochemical cycling.