cssi/SciSciGPT-SciSciNet huggingface dataset:
HOW ROCKY ARE THEY? THE COMPOSITION DISTRIBUTION OF KEPLER’S SUB-NEPTUNE PLANET CANDIDATES WITHIN 0.15 AU

The Kepler Mission has found thousands of planetary candidates with radii between 1 and 4 . These planets have no analogues in our own solar system, providing an unprecedented opportunity to understand the range and distribution of planetary compositions allowed by planet formation and evolution. A precise mass measurement is usually required to constrain the possible composition of an individual super-Earth-sized planet, but these measurements are difficult and expensive to make for the majority of Kepler planet candidates (PCs). Fortunately, adopting a statistical approach helps us to address this question without them. In particular, we apply hierarchical Bayesian modeling to a subsample of Kepler PCs that is complete for days and and draw upon interior structure models that yield radii largely independent of mass by accounting for the thermal evolution of a gaseous envelope around a rocky core. Assuming the envelope is dominated by hydrogen and helium, we present the current-day composition distribution of the sub-Neptune-sized planet population and find that H+He envelopes are most likely to be ∼1% of these planets’ total masses with an intrinsic scatter of ±0.5 dex. We address the gaseous/rocky transition and illustrate how our results do not result in a one-to-one relationship between mass and radius for this sub-Neptune population; accordingly, dynamical studies that wish to use Kepler data must adopt a probabilistic approach to accurately represent the range of possible masses at a given radius.
Correcting real exchange rate misalignment : conceptual and practical issues

This paper studies the issue of real exchange rate misalignment and the difficulties in settling international real exchange rate disputes. The authors show theoretically that determining when a country should be sanctioned for real exchange rate "manipulations" is difficult: in some situations a country's real exchange rate targeting can be beneficial to other countries, while in others it is not. Regardless, it is difficult to establish whether a misaligned real exchange rate is intentionally manipulated rather than unintentionally caused by other policies or by various distortions in the economy. The paper continues by illustrating the difficulty in measuring real exchange rate misalignment, and provides a critical assessment of existing methodologies. It concludes by proposing a new method for measuring real exchange rate misalignment based on differences in marginal products between producers of tradable and non-tradable goods.
k-Dependence and Domination in Kings Graphs.

For most choices of k = 0, ... , 8, there is a tidy solution: an upper bound can be proved by a short elementary argument, and an arrangement of kings can be con structed to show that the upper bound is tight. These limiting densities are given in Section 6. However, tight upper bounds are not yet known for either k = 4 or k ? 5. It is easy to construct arrangements of kings (on arbitrarily large boards) that achieve the densities of 3/5 and 9/13 for k ? 4 and 5, respectively. We conjecture that these are indeed the maximum limiting densities. The story in the present article concerns the struggle to support this conjecture by good upper bounds, as well as the variety of rival techniques used for different val ues of k. Along the way, we make elementary use of graph theory, number theory, group theory, real analysis, and integer linear programming. We believe the methods of the present paper can provide the basis for undergraduate research projects on re lated problems.
Topological relation between bulk gap nodes and surface bound states: Application to iron-based superconductors

In the past few years materials with protected gapless surface (edge) states have risen to the central stage of condensed matter physics. Almost all discussions centered around topological insulators and superconductors, which possess full quasiparticle gaps in the bulk. In this paper we argue that systems with topological stable bulk nodes offer another class of materials with robust gapless surface states. Moreover the location of the bulk nodes determines the Miller index of the surfaces that show (or do not show) such states. Measuring the spectroscopic signature of these zero modes allows a phase-sensitive determination of the nodal structures of unconventional superconductors when other phase-sensitive techniques are not applicable. We apply this idea to gapless iron-based superconductors and show how to distinguish accidental from symmetry-dictated nodes. We shall argue that the same idea leads to a method for detecting a class of the elusive spin liquids.
Effects of Aperiodicity and Roughness on Coherent Heat Conduction in Superlattices

Coherent phonon heat conduction has recently been confirmed experimentally in superlattice structures. Such traveling coherent phonon waves in superlattices lead to a linear increase in thermal conductivity as the number of periods increases. For applications such as thermal insulation or thermoelectrics, minimization of the phonon coherent effect is desirable. In this work, we use molecular dynamics simulations to study how to control coherent heat conduction in superlattices (SLs). It is found that either aperiodic SLs or SLs with rough interfaces can significantly disrupt coherent heat conduction when the interface densities are high. For sample thickness less than 125 nm, aperiodic SLs with perfect interfaces are found to have the lowest thermal conductivity. We use the atomic Green’s function method to examine the phonon dynamics. The impact of either aperiodicity or interface roughness is attributed to reduced transmittance. Such impact diminishes as the interface density reduces.
Online Shopping Intermediaries: The Strategic Design of Search Environments

An online shopping intermediary is an Internet platform on which consumers and third-party sellers transact. Shopping intermediaries provide a search environment (e.g., search aids) to lower the search costs incurred by consumers when finding and evaluating sellers’ products. We study strategic incentives of an intermediary in the design of its search environment as a means to ease search costs. An important aspect of our analysis is that consumers optimally decide how many sellers to evaluate and how deeply (e.g., number of attributes) to evaluate each of them. We find that the equilibrium search environment embeds sufficiently high search costs to prevent consumers from evaluating too many sellers, but not too high to cause them to evaluate sellers’ products at partial depth.
The effect of hospital/physician integration on hospital choice

In this paper, we estimate how hospital ownership of physicians' practices affects their patients' hospital choices. We match data on the hospital admissions of Medicare beneficiaries, including the identity of their physician, with data on the identity of the owner of their physician's practice. We find that a hospital's ownership of a physician dramatically increases the probability that the physician's patients will choose the owning hospital. We also find that patients are more likely to choose a high-cost, low-quality hospital when their physician is owned by that hospital.
Short and Stateless Signatures from the RSA Assumption

We present the first signature scheme which is "short", stateless and secure under the RSA assumption in the standard model. Prior short, standard model signatures in the RSA setting required either a strong complexity assumption such as Strong RSA or (recently) that the signer maintain state. A signature in our scheme is comprised of one element in ${\mathcal {Z}{^*}_{N}}$ and one integer. The public key is also short, requiring only the modulus N, one element of ${\mathcal {Z}{^*}_{N}}$, one integer and one PRF seed. To design our signature, we employ the known generic construction of fully-secure signatures from weakly-secure signatures and a chameleon hash. We then introduce a new proof technique for reasoning about weakly-secure signatures. This technique enables the simulator to predict a prefix of the message on which the adversary will forge and to use knowledge of this prefix to embed the challenge. This technique has wider applications beyond RSA. We use it to provide an entirely new analysis of the security of the Waters signatures: the only short, stateless signatures known to be secure under the Computational Diffie-Hellman assumption in the standard model.
Efficiency in repeated trade with hidden valuations

We analyze the extent to which efficient trade is possible in an ongoing relationship between impatient agents with hidden valuations (i.i.d. over time), restricting attention to equilibria that satisfy ex post incentive constraints in each period. With ex ante budget balance, efficient trade can be supported in each period if the discount factor is at least one half. In contrast, when the budget must balance ex post, efficiency is not attainable, and furthermore for a wide range of probability distributions over their valuations, the traders can do no better than employing a posted price mechanism in each period. Between these extremes, we consider a “bank” that allows the traders to accumulate budget imbalances over time, but only within a bounded range. We construct non-stationary equilibria that allow traders to receive payoffs that approach efficiency as their discount factor approaches one, while the bank earns exactly zero expected profits. For some probability distributions there exist equilibria that yield exactly efficient payoffs for the players and zero profits for the bank, but such equilibria require high discount factors.
Why Natural Selection Cannot Explain Biological Evolution

The indifferent process of natural selection has been dubbed “the blind watchmaker” by Richard Dawkins. Arguments against natural selection are presented that relate to both ontology (reason-based) and epistemology (evidence-based), and the belief that the blind watchmaker drives evolution is revealed to be only a stipulation, at best. The belief is found coming from a metaphysical preference towards naturalism. A new account of evolution is presented that does not hold naturalism as a preference, and permits teleological (or guided) evolution and vitalism. This new account departs from the hidden agenda of naturalism, and fully discloses its preference towards self-evidence in its pursuit of truth.
Susy and Such

In these lectures, the author discusses the theoretical motivation for supersymmetric theories and introduce the minimal low energy effective supersymmetric theory, (MSSM). I consider only the MSSM and its simplest grand unified extension here. Some of the other possible low-energy SUSY models are summarized. The particles and their interactions are examined in detail in the next sections and a grand unified SUSY model presented which gives additional motivation for pursuing supersymmetric theories.
Small-time expansions for state-dependent local jump–diffusion models with infinite jump activity

Abstract In this article, we consider a Markov process { X t } t ⩾ 0 , which solves a stochastic differential equation driven by a Brownian motion and an independent pure jump component exhibiting both state-dependent jump intensity and infinite jump activity. A second order expansion is derived for the tail probability P [ X t ⩾ x + y ] in small time t , where x is the initial value of the process and y > 0 . As an application of this expansion and a suitable change of the underlying probability measure, a second order expansion, near expiration, for out-of-the-money European call option prices is obtained when the underlying stock price is modeled as the exponential of the jump–diffusion process { X t } t ⩾ 0 under the risk-neutral probability measure.
The structure of lobbying and protection in U.S. agriculture

The author surveys the empirical literature on the political economy of agricultural protection. He uses a detailed data set of agricultural Political Action Committee (PAC) contributions over five U.S. congressional election cycles over the 1991-2000 period to investigate the relationship between lobbying spending and agricultural protection. A detailed graphical analysis of campaign contributions by the agricultural PACs indicates that although there are very many PACs, in most sectors the majority of contributions are made by very few PACs. Econometric analysis reveals that lobbying spending by agricultural PACs is positively associated with the use of nontariff barriers and specific tariffs by the United States. There is a strong association between the average U.S. tariff on goods that benefit from U.S. export subsidies and lobbying spending. And there is no association between agricultural protection and trade measures such as import penetration and the export-to-output ratio.
Palladium-Catalyzed Enantioselective Decarboxylative Allylic Alkylation of Cyclopentanones

The first general method for the enantioselective construction of all-carbon quaternary centers on cyclopentanones by enantioselective palladium-catalyzed decarboxylative allylic alkylation is described. Employing the electronically modified (S)-(p-CF3)3-t-BuPHOX ligand, α-quaternary cyclopentanones were isolated in yields up to >99% with ee’s up to 94%. Additionally, in order to facilitate large-scale application of this method, a low catalyst loading protocol was employed, using as little as 0.15 mol % Pd, furnishing the product without any loss in ee.
Nonparametric Regression Analysis of Longitudinal Data

Nonparametric approaches have recently emerged as a flexible way to model longitudinal data. This entry reviews some of the common nonparametric approaches to incorporate time and other covariate effects for longitudinally observed response data. Smoothing procedures are invoked to estimate the associated nonparametric functions, but the choice of smoothers can vary and is often subjective. Both fixed and random effects may be included for vector or longitudinal covariates. A closely related type of data is functional data, where the prevailing approaches to model random effects are through functional principal components analysis and B-splines. Related semiparametric regression models also play an increasingly important role. Keywords: functional data analysis; scatter-plot smoother; mean curve; fixed effects; random effects; principal components analysis; semiparametric regression
Demonstration of a Degenerate Band Edge in Periodically-Loaded Circular Waveguides

We demonstrate the existence of a special degeneracy condition, called degenerate band edge (DBE), between two Bloch modes in periodically-loaded circular all-metallic waveguides at microwave frequencies. The DBE condition has been associated with a dramatic reduction in group velocity and with some unique resonance properties, but it has not been shown in hollow waveguide structures yet. Hence, we show here its existence in two periodic waveguide examples. The unit cell of the first structure is composed of a circular waveguide loaded with two inner cylinders with elliptical irises with misaligned angles. The second structure is composed by loading the waveguide with elliptical rings. The demonstration of DBE in those waveguide is explained through a simple multi-transmission line approach where the conditions to obtain DBE are clarified, and suggests that the DBE can occur in several other analogous periodic waveguides. These structures can be potentially used to investigate unconventional gain schemes in traveling wave tubes or other kinds of distributed amplifiers, oscillators and novel pulse compressors.
Statistical Challenges in Microrheology

Microrheology is the study of the properties of a complex fluid through the diffusion dynamics of small particles, typically latex beads, moving through that material. Currently, it is the dominant technique in the study of the physical properties of biological fluids, of the material properties of membranes or the cytoplasm of cells, or of the entire cell. The theoretical underpinning of microrheology was given in Mason and Weitz (Physical Review Letters; 1995), who introduced a framework for the use of path data of diffusing particles to infer viscoelastic properties of its fluid environment. The multi-particle tracking techniques that were subsequently developed have presented numerous challenges for experimentalists and theoreticians. This study describes some specific challenges that await the attention of statisticians and applied probabilists. We describe relevant aspects of the physical theory, current inferential efforts and simulation aspects of a central model for the dynamics of nano-scale particles in viscoelastic fluids, the generalized Langevin equation.
Tandem 6π-Electrocyclization and Cycloaddition of Nitrodienes to Yield Multicyclic Nitroso Acetals

Upon heating, nitrodienes rearrange through 6pi-electrocyclization to form nitronate intermediates, which can be captured through tandem [3 + 2] dipolar cycloadditions to form highly functionalized nitroso acetals. The one-pot, two-step domino process is highly efficient, proceeding with good facial selectivity and exoselectivity. Dipolarophiles featuring electron-rich, -neutral, and -deficient carbon-carbon double bonds are viable substrates for [3 + 2] cycloadditions with the in situ generated nitronates. In addition, the highly functionalized nitroso acetal products can be hydrogenolyzed selectively to form densely functionalized spirocyclic hydroxy amides or hydroxy gamma-amino acids.
Ribonucleoprotein particles from Escherichia coli

In exponential cultures, 25% of the dry weight of E. coli is accounted for by RNA. Of this about 80 to 90% is present in ribonucleoprotein particles and 10 to 20% in the “soluble” or “non-sedimentable” fraction. Magnesium stabilizes the particles, and on varying its concentration, four kinds of components are observed, with sedimentation constants of 30, 50, 70 and 100 S . 70 S is formed of one 30 S and one 50 S ; 100 S , of two 70 S . Each type of particle has been isolated. They all contain about 63% RNA and 37% protein, and have the same density. The molecular weights of the 30 S , 50 S and 70 S particles are about 0·7 × 10 6 , 1·8 × 10 6 , and 2·6 × 10 6 respectively.
Total synthesis of RK-397

An enantioselective synthesis of the polyene macrolide RK-397 is described. The use of the same eight-carbon building block twice for the construction of the polyol chain allowed for a highly convergent synthesis. The synthesis highlights stereoselective vinylogous aldol addition using a chiral bisphosphoramide as well as a sequential palladium-catalyzed cross-coupling reaction for the preparation of key fragments.
Do core and non-core cash flows from operations persist differentially in predicting future cash flows?

This study investigates the persistence of cash flow components (core and non-core cash flows) using a cash flow prediction model. By extending the Barth, Cram, and Nelson (Account Rev 76(January):27–58, 2001) model, we examine the role of cash flow components in predicting future cash flows beyond that of accrual components. We propose a cash flow prediction model that decomposes cash flows from operations into core and non-core cash flow components that parallel the presentation and format of operating income from the income statement. Consistent with the AICPA and financial analysts’ recommendations, and as predicted, we find that core and non-core cash flows defined in our paper are differentially persistent in predicting future cash flows; and these cash flow components enhance the in-sample predictive ability of cash flow prediction models. We also analyze the association of in-sample prediction errors with earnings, cash flow and accruals variability. We find that disaggregating cash flows improve in-sample prediction, especially for large firms with high cash flows and earnings variability.
Bases of wormholes in quantum cosmology

We argue that if the space of physical states spanned by the wormhole wavefunctions can be equipped with a Hilbert structure, such a Hilbert space must coincide with that of the Lorentzian gravitational system under consideration. This statement is rigorously proved in the case of a Friedmann--Robertson--Walker spacetime minimally coupled to a massless scalar field. For this minisuperspace, the physical inner product can be determined by imposing a set of Lorentzian reality conditions, and the Hilbert space obtained in this way turns out to admit a basis of wormhole solutions. As a particular consequence, every proper quantum state can be interpreted as a superposition of wormholes. We also discuss various admissible choices of bases of wormholes for this model and show that the wavefunctions that form each of these bases are eigenfunctions of a complete set of compatible observables. The associated eigenvalues then provide a set of well-defined wormhole parameters, in the sense that they can be employed to specify the different elements of the bases of wormholes.
Modification of the magnetic flux-line interaction at a superconductor's surface

Abstract The pair interaction between magnetic flux-lines in a semi-infinite slab of an anisotropic type-II superconductor in an external field is derived in the London limit. The case where the applied field is normal to the superconductor/vacuum interface is considered. The presence of stray fields near the surface leads to an additional contribution to the repulsive interaction between flux lines that vanishes exponentially with the distance from the interface. The pair interaction is used to obtain the continuum elastic energy of a distorted semi-infinite flux-line array. The presence of the superconductor/vacuum interface yields surface contributions to the compressional and tilt elastic constants.
Growth of Sr6Rh5O15 Single Crystals from High-Temperature Solutions: Structure Determination Using the Traditional 3-D and the 4-D Superspace Group Methods and Magnetic Measurements on Oriented Single Crystals

Single crystals of Sr6Rh5O15 were grown from a molten potassium carbonate flux. The structure was solved by both the traditional 3-D crystallographic approach and the 4-D superspace group approach using JANA2000. Both methods produced an equivalent structure determination, thereby confirming the 4-D superspace group approach as an effective structure solution method for 3-D commensurate composite structures. Sr6Rh5O15 corresponds to the n = 1, m = 1 member of the A3n+3mA‘nB3m+nO9m+6n family of 2H hexagonal perovskite-related oxides. This compound is characterized by pseudo-one-dimensional polyhedral chains of four face-sharing RhO6 octahedra followed by one RhO6 trigonal prism. These chains in turn are separated by [Sr]∞ chains. Magnetic measurements were carried out on oriented single crystals, and a very large magnetic anisotropy in the magnetic susceptibility was observed.
Anomalies: Is it the Economy?

There is still no consensus on whether small firm or value stock anomalies exist. We examine the last half of the 20th century and apply a six-factor macroeconomic model to test for the presence of these abnormal returns. Using four proxies for value, we find that detecting this anomaly is sensitive to choice of proxy, the magnitude of the abnormal returns varies over time, and the anomaly does not persist through time. Additional tests provide evidence that abnormal returns for small, value-oriented, and growth-oriented firms differ significantly under restrictive versus expansive monetary policy regimes.
Mass-transported off-axis refractive GaP microlenses for use in a distortionless optical interconnect system

An array of aspheric off-axis GaP microlenses fabricated by mass-transport smoothing has been used to eliminate distortion in an optical interconnection system employing a single macroscopic relay lens. System design and experimental results are presented.
Use of a spectrally tunable source to explore improvement in chromatic contrast for illumination of tissues

Human vision by a clinical practitioner is often the first disease detection tool. Illumination for such procedures as endoscopy use broadband white light, with luminance level being the only control available. The use of staining dyes for contrast improvement have shown limited adoption due to the additional steps needed and small number of approved dyes for in vivo use. Here we explore the control of the illuminant spectral distribution to improve chromatic contrast without the use of dyes. The computational steps used in converting spectral data to RGB and use of the CIELAB chromatic and luminance contrast metric as criteria in determining the appropriate lighting spectral distribution will be discussed. The skin on the back of the hand and the skin section over a vein are used as examples of tissue features to be contrasted. A 3-wavelelength LED lamp and an incandescent lamp with the yellow spectral region filtered out are shown as examples that spectrally-shaped illumination can enhance visual contrast.
An ab initio study of 7-norbornenyl and 7-norbornadienyl anions: The absence of bis-homoantiaromaticity

Abstract Ab initio calculations are reported for the 7-norbornyl, syn - and anti -7-norbornenyl, and the 7-norbornadienyl carbanions. Homodesmotic comparisons and gas phase proton affinity data reveal no evidence for bis-homoantiaromaticity in the syn -7-norbornenyl system. Each of the ions is stablized, inter alia , by delocalization of the negative charge into anti-parallel CC bonds of the molecular framework giving rise to lengthened sigma bonds. Each of these ions was found to be more stable than methyl carbanion as measured by proton affinity calculations. Electron affinity calculations for the corresponding radicals were more positive than that for methyl radical.
A Universal Online Caching Algorithm Based on Pattern Matching

We present a universal algorithm for the classical online problem of caching or demand paging. We consider the caching problem when the page request sequence is drawn from an unknown probability distribution and the goal is to devise an efficient algorithm whose performance is close to the optimal online algorithm which has full knowledge of the underlying distribution. Most previous works have devised such algorithms for specific classes of distributions with the assumption that the algorithm has full knowledge of the source. In this paper, we present a universal and simple algorithm based on pattern matching for mixing sources (includes Markov sources). The expected performance of our algorithm is within 4+o(1) times the optimal online algorithm (which has full knowledge of the input model and can use unbounded resources).
A New Method for Finding Topological Separators in a Magnetic Field

Magnetic topology is a powerful tool for constraining certain physical properties of a given magnetic configuration, including the strengths and locations of current sheets, relative helicity and the magnetic free energy available for reconnection. A critical feature of magnetic topology is the separator, a field line bordering several different regions of connectivity. With existing methods, these field lines are at best computationally expensive and at worst impossible to find. A new method is presented for finding the Minimal Separator Set, all of the separators that necessarily exist in a configuration, and to use this information in combination with the optical analogy and a simulated annealing method to ‘cool’ an initial guess for each separator into a good approximation.
Electrochemically assisted Heck reactions.

During efforts to develop chip-based Heck reaction chemistry, it was discovered that normal solution-phase Heck reactions can be dramatically accelerated using electrochemistry. The acceleration makes room temperature Heck reactions proceed at synthetically useful rates in the absence of added ligand. Presumably, the current passed through the reaction maintains a high level of active catalyst.
Data-mined similarity function between material compositions

A new method for assessing the similarity of material compositions is described. A similarity measure is important for the classification and clustering of compositions. The similarity of the material compositions is calculated utilizing a data-mined ionic substitutional similarity based upon the probability with which two ions will substitute for each other within the same structure prototype. The method is validated via the prediction of crystal structure prototypes for oxides from the Inorganic Crystal Structure Database, selecting the correct prototype from a list of known prototypes within five guesses 75% of the time. It performs particularly well on the quaternary oxides, selecting the correct prototype from a list of known prototypes on the first guess 65% of the time.
A rapid blade-to-blade solution for use in turbomachinery design

A rapid technique for solving the blade-to-blade turbomachinery flow problem was developed. Approximate governing flow equations, which include the effects of compressibility, radius change, rotation, and variable stream sheet thickness are solved using a panel method. The development and solution of these equations are described. Sample calculations are presented to illustrate the method's capabilities and accuracy. Previously announced in STAR as N83-13077
Synthesis in molten alkali metal polythiophosphate fluxes. The new quaternary bismuth and antimony thiophosphates ABiP2S7 (A = K, Rb), A3M(PS4)2 (A = K, Rb, Cs; M = Sb, Bi), Cs3Bi2(PS4)3, and Na0.16Bi1.28P2S6

Abstract We used the molten alkali metal polychalcogenide flux method to prepare the new compounds ABiP2S7 (A = K, Rb), A3M(PS4)2 (A = K, Rb, Cs; M = Sb, Bi), Cs3Bi2(PS4)3, and Na0.16Bi1.28P2S6. KBiP2S7 crystallizes in the monoclinic space group P21/c with a = 9.500(3) A , b = 12.303(4) A , c = 9.097(3) A , β = 90.59(3)°, V = 1063 A 3 , at 23°C. Dcalc = 3.34 g cm−3, μ = 184.85 cm−1, 2θmax = 50° Mo Kα. Data with I > 3σ(I) 1672, R/Rw(%) = 2.8/3.1. K3Bi(PS4)2 crystallizes in the orthorhombic space group P212121 with a = 23.894(8)(3)A, b = 6.799(3)A, c = 9.049(2)A, V = 1470A3, at −60°C. Dcalc = 2.91 g cm−3, μ = 140.8 cm−1, 2θmax = 50°. Data with I > 3σ(I) 1745, R/Rw(%) = 5.5/6.0. Cs3Bi2(PS4)3 crystallizes in the monoclinic space group P21/c with a = 18.091(5) A , b = 6.791(2) A , c = 18.723(3) A , β = 97.95(2)°, V = 2278 A 3 , at 23°C. Dcalc = 3.77 g cm−3, μ = 213.3 cm−1, 2θmax = 50°. Data with I > 3σ(I) 2623, R/Rw(%) = 7.0/9.0. Na0.16Bi1.28P2S6 crystallizes in the monoclinic space group P21/n with a = 6.554(2) A , b = 7.297(2) A , c = 9.371(1) A , β = 92.04(2)°, V = 447.8 A 3 , at 23°C. Dcalc = 3.73 g cm−3, μ = 236.2 cm−1, 2θmax = 50°. Data with I > 3σ(I) 892, R/Rw(%) = 7.7/8.5. The structural diversity in this family of compounds ranges from the one-dimensional non-centrosymmetric chains of A3M(PS4)2 and the layered compounds, ABiP2S7 and Cs3Bi2(PS4)2, to the dense three-dimensional framework of Na0.16Bi1.28P2S6. KBiP2S7 is a layered solid with a complex new structure type, where corrugated layers are separated by eight-coordinate K+ ions. It contains a [P2S7]4− ligand in a complicated coordination mode. The structure of K3Bi(PS4)2 is assembled from one-dimensional, helical [Bi(PS4)2]n3n− chains running along the crystallographic b-axis. The chain structure features two interesting binding modes for a tetrahedral [PS4]3− ligand. The structure of Cs3Bi2(PS4)3 has layers containing the same one-dimensional helical chains observed in K3Bi(PS4)2. However, the PS4 unit acts as a bridge to a Bi2(PS4)2 dimeric unit. This unit is linked to another chain via a second bridging PS4 ligand to form sheets that are parallel to the [101] crystallographic plane. The structure of Na0.16Bi1.28P2S6 is three dimensional but consists of layers of P2S6 groups in the a-b plane separated by a single layer of Bi3+ ions. The ethane-like [P2S6]4− ligand chelates to eight Bi atoms in a very convoluted fashion. Positional disorder was found between Na and Bi ions in one crystallographic site. Their synthesis, structural characterization, optical absorption and thermal properties are reported.
Analysis of Long Rod Penetration at Hypervelocity Impact

The hypervelocity impact (>3 km/sec) of a long rod penetrator against thin targets of like material was studied analytically with the aid of the HELP code, a two-dimensiona l, finite-difference Eulerian computer code. The results were compared with experimental data. The analytical examination of the effect of strength showed no perturbation. The computations of projectile residual speed deviated by no more than 3% from the experimental data; of residual mass by no more than 16%; of final rod length by no more than 5%; and of target exit diameter by no more than 8%. This agreement demonstrated that the HELP code can serve as a useful analytical tool for the study of kinetic energy projectile penetration of hypervelocity impact. HE study of the dynamic response of materials to intense impulsive loading may be approached from three distinct points of view: experimental, analytical, and numerical. In the experimental approach tests are conducted to deduce relationships between various parameters from the observed results. Generally many data points (therefore many tests) are required, so that this approach becomes both time consuming and expensive, especially in the hypervelocity regime (striking velocities > 3 km/sec). To obtain some knowledge of the physics of the deformation process and at the same time reduce the number of tests, recourse is made to analytical methods. Simplifying assumptions are introduced into the governing equations of continuum physics, and these are reduced to a set of partial differential equations which characterize the elastic-plastic hydrodynamic response of a material or structure. Very often the resulting differential equations are mathematically intractable and further ap- proximations must be introduced to obtain an approximate analytical solution, at the expense of reducing the scope of the problem. With the present availability of large digital com- puters, however, there now exists the realization that systems of differential equations never attempted before can be solved. The main advantage of computer utilization is that parameters can be varied easily and quickly in any problem and their effects noted and compared. Furthermore, even if only a part of the problem can be formulated correctly, several methods of complete formulation can be assumed and a determination of which is the best or most sensible solution can be made. The objectives of this study were twofold: to ascertain the effect of material strength on target and projectile defor- mations with varying target thickness, and to determine the applicability of the HELP code to study hypervelocity (HV) impact of long rod kinetic energy penetrators by validating, if possible, the numerical results with experimental data.
A compact and robust method for spectropolarimetry

Motivated by astrobiological remote sensing needs, Sparks et al. (2012) 1 present an approach to spectropolarimetry which offers the prospect of high sensitivity over a very wide wavelength range (UV, optical, IR). Using static, robust components the polarization information is encoded onto one dimension of a two-dimensional data array, while the other dimension records the spectrum. A spatially varying retardance along the spectrograph slit, followed by a polarization analyzer, encodes the Stokes parameters as coefficients of orthogonal trigonometric functions perpendicular to the spectrum. No moving parts are required and all polarimetric information is available on a single data frame, hence the technique is immune to time dependencies, free of fragile modulating components, has the potential for high sensitivity while offering a wide wavelength range with full Stokes spectropolarimetry. Within the Solar System, spectropolarimetry offers diagnostics for dust (cometary, zodiacal, rings), surfaces (rocky, regolith, icy), aerosols (clouds, dust storms) and high energy plasma emission processes. Beyond the Solar System, space-based telescopic spectropolarimetry has important contributions to make in the detection of extrasolar planets and their characterization. There are astrobiological applications for full Stokes polarimetry stemming from the interaction of light with chiral living organisms, which offers the potential for a remote sensing detection capability for microbial life.
LUISA CAPETILLO Y SALVADORA MEDINA ONRUBIA DE BOTANA: DOS ÍCONOS ANARQUISTAS. UNA COMPARACIÓN

Luisa Capetillo y Salvadora Onrubia de Botana fueron dos militantes anarquistas de principios del siglo XX, de Puerto Rico y Argentina respectivamente, que comparten una serie de caracteristicas comunes. Ambas son un verdadero icono del anarco- ~ feminismo que se desarrolla conjuntamente con otras manifestaciones de la vanguardia de los anos 20. Fueron periodistas, escritoras y militantes. Asimismo, son las primeras dramaturgas de Latinoamerica, desarrollando un teatro feminista autenticamente revolucionario. La unidad tematica que se encuentra en sus obras revela la existencia de una intertextualidad anarco-feminista entre las Americas.
Existence of Solutions to the Bethe Ansatz Equations for the 1D Hubbard Model: Finite Lattice and Thermodynamic Limit

In this work, we present a proof of the existence of real and ordered solutions to the generalized Bethe Ansatz equations for the one dimensional Hubbard model on a finite lattice, with periodic boundary conditions. The existence of a continuous set of solutions extending from any U>0 to U=∞ is also shown. We use this continuity property, combined with the proof that the norm of the wavefunction obtained with the generalized Bethe Ansatz is not zero, to prove that the solution gives us the ground state of the finite system, as assumed by Lieb and Wu. Lastly, for the absolute ground state at half-filling, we show that the solution converges to a distribution in the thermodynamic limit. This limit distribution satisfies the integral equations that led to the Lieb-Wu solution of the 1D Hubbard model.
A New Sample of Low-Mass Black Holes in Active Galaxies

We present an expanded sample of low-mass black holes (BHs) found in galactic nuclei. Using standard virial mass techniques to estimate BH masses, we select from the Fourth Data Release of the Sloan Digital Sky Survey all broad-line active galaxies with masses <2 × 106 M☉. BHs in this mass regime provide unique tests of the relationship between BHs and galaxies, since their late-type galaxy hosts do not necessarily contain classical bulges. Furthermore, they provide observational analogs of primordial seed BHs and are expected, when merging, to provide strong gravitational signals for future detectors such as LISA. From our preliminary sample of 19, we have increased the total sample by an order of magnitude to 174, as well as an additional 55 (less secure) candidates. The sample has a median BH mass of MBH = 1.3 × 106 M☉, and in general the objects are radiating at high fractions of their Eddington limits. We investigate the broad spectral properties of the sample; 55 are detected by ROSAT, with soft X-ray luminosities in the range 1040 to 7 × 1043 ergs s-1. Much like the preliminary sample, these objects are predominantly radio-quiet (R ≡ f6cm/f4400A < 10), but 11 objects are detected at 20 cm, with radio powers (1021-1023 W Hz-1) that may arise from either star formation or nuclear activity; only 1% of the sample is radio-loud. We further confirm that, with Mg = -19.3 and g - r = 0.7 mag, the host galaxies are low-mass, late-type systems. At least 40% show disklike morphologies, and the combination of host galaxy colors and higher order Balmer absorption lines indicate intermediate-age stellar populations in a subset of the sample.
A randomized prospective comparison of intermittent methotrexate, methotrexate with leucovorin, and a methotrexate combination in head and neck cancer

A randomized prospective clinical trial involved 259 cases of advanced recurrent Stage III and IV epidermoid cancers of the head and neck. The cases were randomized among three treatment programs evaluating two dose schedules and a combination treatment of methotrexate. The treatments consisted of: weekly methotrexate, biweekly methotrexate with leucovorin rescue (ML), and biweekly ML combined with cyclophosphamide and cytosine arabinoside (MLCC). Equivalent overall drug-related toxicity was produced with a 5% drug-related fatality rate. Methotrexate alone produced significantly more skin and mucosal toxicity, and the combination (MLCC) resulted in more hematologic toxicity than other treatments. Complete and partial objective responses were achieved in 26%, 24%, and 18% by each treatment. Methotrexate alone produced a median duration of response and 105 days compared with 42 and 49 days from the other treatments. Duration of response was significantly longer and survival was better in the methotrexate-alone group. Response was markedly stage dependent; 40% of Stage III patients achieved response, whereas only 17% of Stage IV patients responded. Presence of visceral metastases decreased response rates and the likelihood of response was particularly compromised by pulmonary metastatic spread; only seven of 54 such patients responded. Decreased survival was related to non-ambulatory performance status, disease-free intervals of less than one year and weight loss. Survival differences between Stage III and IV patients could not be shown. This study demonstrates the therapeutic superiority of weekly i.v. treatment with methotrexate but failed to support claims of an improved therapeutic index for high-dose methotrexate with leucovorin rescue. As the only randomized prospective clinical trial of chemotherapy in advanced head and neck cancer, this study reinforces the weekly i.v. schedule of methotrexate as the standard against which other drug schedules and drug combinations should be compared.
Positive harmonic functions on Denjoy domains in the complex plane

Let Ω be a domain in the complex plane C whose complement E=\(\overline C \backslash \Omega \) is a subset of the real line (i.e., Ω a Denjoy domain). If each point of E is regular for the Dirichlet problem in Ω, we provide a geometric description of the structure of E near infinity such that the Martin boundary of Ω has one or two “infinite” points.
A novel concept for a satellite-based maritime search and rescue system

Search and rescue (SAR) for both airborne and maritime vehicles has been an area of intense investigation for many years. Current techniques include employment of small distress transmitters which provide signals that have only a limited interception capability. This can considerably increase the search time and reduce its effectiveness. With the increased availability-existing and planned-of both synchronous and nonsynchronous satellites, SAR investigations are being directed toward the application of satellites. The present paper introduces the concept of satellite-based maritime search and rescue system (SAMSARS). This is a proposed pseudonoise (PN) wide-band spread spectrum system that would operate at low power levels and coexist with operational communication satellite systems (voice or data) without mutual interference. The use of existing operational satellite spectrum, instead of a dedicated distress channel or special satellites, is a major feature of SAMSARS. Other important aspects are its capability of providing unique identification and distress information in minutes following activation of the distress transmitter and its inherent immunity to false alarms. SAMSARS can also provide position location directly when three satellites are mutually visible or indirectly, by taking advantage of a vessel's on-board derived navigation data. This paper presents concept elements such as message structure, transmitter and receiver block diagrams, and unique features of SAMSARS. The paper also presents an operational example, including sample link power budgets, and finally specifies areas for further investigation.
A novel wiggler design for use in a high-efficiency free-electron laser

Abstract A wiggler, for use in a high-efficiency FEL system utilizing microwave acceleration to maintain synchronism, is proposed. The wiggler not only provides a periodic transverse magnetic field, but also acts as a loaded waveguide capable of supporting microwaves. Measurements on the wiggler confirm that it can be utilized in a high-efficiency design to attain conversion efficiencies of approximately 42% in a 2 m length at 10 μm wavelength.
The 2001 Superoutburst of WZ Sagittae: A Clue to the Dynamics of Accretion Disks

We examine the light curve of the 2001 July-August superoutburst of WZ Sagittae. During the decline from maximum light the locally defined decay time increases from ~4 to ~12 days mag-1 over the first ~15 days of the ~25 day superoutburst, as the system faded from mV 8.5 to mV 10. The superoutburst is caused by the sudden accretion of ~1024 g of gas onto the white dwarf, and the deviation from exponentiality in the decay light curve is expected qualitatively during a "viscous decay" in which the dominant mode of depletion of the gas stored in the accretion disk is accretion onto the central object. In other words, as the mass of the accretion disk decreases, the viscous timescale increases. We show that the data are also quantitatively consistent with the theoretical viscous decay time, both calculated via a simple scaling and also from time-dependent calculations, when one adopts standard model parameters for WZ Sge.
Causes and consequences of magnetic field changes in neutron stars

Abstract Because of the quantum fluid properties of a neutron star core’s neutrons and protons, its magnetic field is expected to be coupled strongly to its spin. This predicts a simple evolution of the surface-field of such stars as they spin down or, less commonly, are spun up. Consequences and comparisons with observations are given for properties of solitary spinning down pulsars, including their glitches and spin-down ages, X-ray pulsars, and the formation and pulse characteristics of Millisecond Pulsars. For none of these is there a present conflict between model predictions and what has been observed.
Fixed points theorems for mappings with non-compact and non-convex domains

This note gives some fixed point theorems for lower and upper semi-continuous mappings and mappings with open lower sections defined on non-compact and non-convex sets. It will be noted that the conditions of our theorems are not only sufficient but also necessary. Also our theorems generalize some well-known fixed point theorems such as the Kakutani fixed point theorem and the Brouwer-Schauder fixed point theorem by relaxing the compactness and convexity conditions.
The Effect of Measurement Alternatives on a Nonfinancial Quality Measure's Forward‐Looking Properties

Drawing on theories from operations, management, and marketing, this paper examines whether three types of measurement alternatives affect the forwardlooking properties of a quality measure. Using proprietary data from a medical services firm, the results show that the strength of the relation between a current quality measure and future quality‐related warranty costs depends on: (1) the standard against which quality is measured, (2) assumptions regarding the relation's symmetry, and (3) assumptions regarding the relation's functional form. Thus, the construction of a quality performance measure may improve its ability to predict future financial performance and, hence, its usefulness for decision making and control. The paper concludes with an illustration of how firms can use a contemporaneous and forward‐looking quality measure to assess quality‐related decisions in a timely manner and shows that those decisions can be affected by the measurement alternatives examined.