cssi/SciSciGPT-SciSciNet huggingface dataset:
Thermodynamic Assessment of the Gallium–Nitrogen System

Thermochemical and phase diagram data for the Ga–N system were assessed by employing the CALPHAD method. A consistent model representation of available thermodynamic properties agrees well with the critically evaluated experimental data. Thermodynamic extrapolation/interpolation of these data was applied to estimate the sublimation and melting characteristics of the GaN compound: at atmospheric pressure of nitrogen, gallium nitride sublimates incongruently by decomposing into nitrogen-rich gas and gallium-rich liquid, but can melt congruently at high nitrogen pressure (≈4.9 GPa).
Getting the Word Out: Notes on the Social Organization of Notification*

Even when the timing, sequence, and manner of notification are instrumentally inconsequential, how one conveys information affects the meaning of the telling. This article introduces the concepts of “notification norms” and the “information order,” showing how the former constrain the behavior of nodes in social networks as well as enabling manipulation of the relationships that comprise those networks. “Notification” is defined as information transmission motivated by role obligations and notification norms as social rules that govern such transmission. These rules produce patterns of information dissemination different from what individual volition would yield and from what technology makes possible. The capacity to wield a socially sanctioned repertoire of notification rules is a learned competence. Competent notifiers must also understand the local epistemological ecology—the distribution and trajectory of information, as well as the projects, concerns, and priorities of one's fellows. This study of n...
Propagation Speed of Gravity and the Relativistic Time Delay

We calculate the delay in the propagation of a light signal past a massive body that moves with speed v, under the assumption that the speed of propagation of the gravitational interaction cg differs from that of light. Using the post-Newtonian approximation, we consider an expansion in powers of v/c beyond the leading "Shapiro" time-delay effect, while working to first order only in Gm/c2, and show that the altered propagation speed of the gravitational signal has no effect whatsoever on the time delay to first order in v/c beyond the leading term, although it will have an effect to second and higher order. We show that the only other possible effects of an altered speed cg at this order arise from a modification of the parameterized post-Newtonian coefficient α1 of the metric from the value 0 predicted by general relativity. Current solar-system measurements already provide tight bounds on such a modification. We conclude that recent measurements of the propagation of radio signals past Jupiter are sensitive to α1 but are not directly sensitive to the speed of propagation of gravity.
Syntheses, structure, and bonding of Rb14(Mg1-xInx)30. A nonstoichiometric phase with an unusual substitution in the anion framework.

The title compound Rb14(Mg1-xInx)30 (x = 0.79−0.88) has been obtained from high-temperature reactions of the elements in welded Ta tubes. There is no analogous binary compound without Mg. The crystal structure established by single-crystal X-ray diffraction means (space group P62m (No. 189), Z = 1 and a = b = 10.1593(3) A, c = 17.783(1) A for x = 0.851) features two distinct types of anionic layers: isolated pentacapped trigonal prismatic In117- clusters and condensed [(MgxIn1-x)5In14]7- layers. The latter consists of analogous M11 (M = Mg/In) fragments that share prismatic edges and are interbridged by trigonal M3 units. The structure shows substantial differences from related A15Tl27 (A = Rb, Cs) in which the cation A that centers a six-membered ring of Tl11 fragments is replaced by M3. Both linear muffin-tin orbital and extended Huckel calculations are used to analyze the observed phase width and site preferences. We further utilize the results to rationalize the distortion of the M11 fragment in the...
Moment Bounds for the Smoluchowski Equation and their Consequences

We prove \(L^{\infty}\big( {\mathbb{R}}^d \times [0,\infty) \big)\) bounds on moments \(X_a : = \sum_{m \in {\mathbb{N}}}{m^{a}f_m(x, t)}\) of the Smoluchowski coagulation equations with diffusion, in any dimension d ≥ 1. If the collision propensities α(n, m) of mass n and mass m particles grow more slowly than \((n + m)\big(d(n) + d(m) \big)\) , and the diffusion rate \(d(\cdot)\) is non-increasing and satisfies \(m^{-b_1} \leq d(m) \leq m^{-b_2}\) for some b1 and b2 satisfying 0 ≤ b2 < b1 < ∞, then any weak solution satisfies \(X_a \in L^{\infty}\big( {\mathbb{R}}^d \times [0,T] \big) \cap L^1 \big( {\mathbb{R}}^d \times [0, T] \big)\) for every \(a \in {\mathbb{N}}\) and T ∈(0, ∞), (provided that certain moments of the initial data are finite). As a consequence, we infer that these conditions are sufficient to ensure uniqueness of a weak solution and its conservation of mass.
Achieving steady-state Bose-Einstein condensation

In the usual method of evaporative cooling used so far in Bose-Einstein condensation ~BEC! experiments @1‐6# ,afi nite number of atoms are collected in a magnetic trap after being laser cooled to a phase space density at least five orders of magnitude below the critical density needed for BEC. The frequency of an external RF radiation field, which spinflips the atoms to an untrapped state, is then lowered continuously. This further cools the gas by removing high energy atoms from the tail of the distribution. This evaporative cooling procedure increases the phase space density above the critical point needed to reach BEC. The success of this method is well established experimentally, allowing many fundamental properties of Bose-Einstein condensation to be investigated @7‐12#. This standard method of achieving BEC has one critical drawback: once a condensate has been obtained, it has a finite lifetime in the trap determined by various loss mechanisms, such as collisions with hot atoms from the background gas, and inelastic collisions between the trapped atoms. Although the finite lifetime of the condensate does not prevent many crucial properties of the system to be studied, it is still very desirable to achieve a steady-state situation so that a condensate can be sustained for an indefinite period of time. Such a situation is essential for the continuous output of a coherent beam of atoms in an atom laser @13‐18# .T o date, no experiment has demonstrated a steady-state condensation. We address this problem by constructing an intuitive model describing the two aspects to such an experiment: The continuous loading of atoms into the magnetic trap and the classical kinetic evolution of the trapped atoms toward a steady state during the evaporation. Our description of the loading procedure is based on the experimental setup described in @19#, where the authors loaded a magnetic trap with atoms which had been cooled in a separate MOT. This allows us to estimate the rate g f that atoms enter the trap below the RF cut, as well as the mean energy e f of the injected atoms. To model the classical kinetic evolution, we assume a truncated Boltzmann distribution for the trapped atoms and obtain rate equations for the total number N(t) and energy E(t) of the system @1,3‐6#. These rate equations include the loss of atoms due to elastic collisions with the backgroundgas atoms, inelastic three-body collisions, and evaporation, as well as the gain of atoms due to loading. We then numerically calculate the steady-state solution of these equations and show plots of the peak phase space density r 0 as a function of the various physical parameters of the system. We show that the critical regime r 0>2.612 may be reached in order to obtain BEC in steady state.
Crystal structure, characterization and thermoelectric properties of the type-I clathrate Ba8-ySryAl14Si32 (0.6≤y≤1.3) prepared by aluminum flux

The title compound was prepared as single crystals using an aluminum flux technique. Single crystal and powder X-ray diffraction indicate that this composition crystallizes in the clathrate type-I structure, space group Pm3n. Electron microprobe characterization indicates the composition to be Ba_(8−y)Sr_yAl_(14.2(2))Si_(31.8(2)) (0.77<y<1.3). Single-crystal X-ray diffraction data (90 and 12 K) were refined with the Al content fixed at the microprobe value (12 K data: R_1=0.0233, wR_2=0.0441) on a crystal of compositions Ba. The Sr atom preferentially occupies the 2a position; mixed Al/Si occupancy was found on all framework sites. These refinements are consistent with a fully occupied framework and nearly fully occupied cation guest sites as found by microprobe analysis. Temperature dependent electrical resistivity and thermal conductivity have been measured from room temperature to 1200 K on a hot-pressed pellet. Electrical resistivity reveals metallic behavior. The negative Seebeck coefficient indicates transport processes dominated by electrons as carriers. Thermal conductivity is between 22 and 25 mW/cm K. The sample shows n-type conductivity with a maximum figure of merit, zT of 0.3 at 1200 K. A single parabolic band model predicts a five-fold increase in zT at 800 K if carrier concentration is lowered.
Chemoselective bromodeboronation of organotrifluoroborates using tetrabutylammonium tribromide: application in (Z)-dibromoalkene syntheses.

Tetrabutylammonium tribromide (TBATB) has been found to be a unique bromodeboronation reagent for organotrifluoroborates. When compared to previously reported bromodeboronation methods, the mild and metal-free reaction conditions tolerate a wider range of functional groups. High regio- and chemoselectivity are observed in the presence of both unsaturated carbon−carbon bonds and aldehyde functional groups. An efficient synthetic route to (Z)-dibromoalkenes from terminal alkynes has been developed using the TBATB-mediated bromodeboronation as a key step.
Vortex-dominated conical-flow computations using unstructured adaptively-refined meshes

A conical Euler/Navier-Stokes algorithm is presented for the computation of vortex-dominated flows. The flow solver involves a multistage Runge-Kutta time stepping scheme which uses a finite-volume spatial discretization on an unstructured grid made up of triangles. The algorithm also employs an adaptive mesh refinement procedure which enriches the mesh locally to more accurately resolve the vortical flow features. Results are presented for several highly-swept delta wing and circular cone cases at high angles of attack and at supersonic freestream flow conditions. Accurate solutions were obtained more efficiently when adaptive mesh refinement was used in contrast with refining the grid globally. The paper presents descriptions of the conical Euler/Navier-Stokes flow solver and adaptive mesh refinement procedures along with results which demonstrate the capability.
Modeling and Analysis of Drug-Eluting Stents With Biodegradable PLGA Coating: Consequences on Intravascular Drug Delivery

Increasing interests have been raised toward the potential applications of biodegradable poly(lactic-co-glycolic acid) (PLGA) coatings for drug-eluting stents in order to improve the drug delivery and reduce adverse outcomes in stented arteries in patients. This article presents a mathematical model to describe the integrated processes of drug release in a stent with PLGA coating and subsequent drug delivery, distribution, and drug pharmacokinetics in the arterial wall. The integrated model takes into account the PLGA degradation and erosion, anisotropic drug diffusion in the arterial wall, and reversible drug binding. The model simulations first compare the drug delivery from a biodegradable PLGA coating with that from a biodurable coating, including the drug release profiles in the coating, average arterial drug levels, and arterial drug distribution. Using the model for the PLGA stent coating, the simulations further investigate drug internalization, interstitial fluid flow in the arterial wall, and stent embedment for their impact on drug delivery. Simulation results show that these three factors, while imposing little change in the drug release profiles, can greatly change the average drug concentrations in the arterial wall. In particular, each of the factors leads to significant and yet distinguished alterations in the arterial drug distribution that can potentially influence the treatment outcomes. The detailed integrated model provides insights into the design and evaluation of biodegradable PLGA-coated drug-eluting stents for improved intravascular drug delivery.
Tetrahydroborate intercalation reagents. Convenient, straightforward routes to known and new types of layered intercalation compounds

On presente une methode generale d'intercalation de diverses molecules cationiques dans des matrices solides en couche utilisant des reactifs au BH 4 . On peut ainsi obtenir des composes tels que [(Ph 3 P) 2 Cu] 0,05 FeOCl
Vibrational and rotational spectroscopy of the first electronically allowed transition of α‐dicarbonyls

Laser induced fluorescence excitation spectra of the series glyoxal, methylglyoxal, biacetyl, and 2,3‐pentanedione at high resolution show that except for glyoxal these molecules undergo a characteristic structural deformation during the transition. Our incomplete assignment of the methylglyoxal spectrum suggests that the methyl internal rotation and carbonyl skeletal motions (probably out of plane) are involved. The positions of the 0–0 bands shift to the blue as a methyl group is added to glyoxal (22 000 cm−1) and methylglyoxal (22 125 cm−1) but not as the side groups are extended from biacetyl (22 336 cm−1) to 2,3‐pentandedione (22 340 cm−1). We cannot precisely identify the interaction between the carbonyls and methyl groups that cause these effects. As the size of the carbon skeleton increases the number of observed low frequency vibronic excitations increases and the energy at which the spectra break off decreases. These observations are consistent with the known radiationless behavior of these molecules.
On periods for string compactifications

Abstract Motivated by recent developments in the computation of periods for string compactifications with c = 9, we develop a complementary method which also produces a convenient basis for related calculations. The models are realized as Calabi-Yau hypersurfaces in weighted projective spaces of dimension four or as Landau-Ginzburg vacua. The calculation reproduces known results and also allows a treatment of Landau-Ginzburg orbifolds with more than five fields.
A Bayesian Sequential Experimental Study of Learning in Games

Abstract We apply a sequential Bayesian sampling procedure to study two models of learning in repeated games. In the first model individuals learn only about an opponent when they play her or him repeatedly but do not update from their experience with that opponent when they move on to play the same game with other opponents. We label this the nonsequential model. In the second model individuals use Bayesian updating to learn about population parameters from each of their opponents, as well as learning about the idiosyncrasies of that particular opponent. We call this the sequential model. We sequentially sample observations on the behavior of experimental subjects in the so-called “centipede game.” This game allows for a trade-off between competition and cooperation, which is of interest in many economic situations. At each point in time, the “state” of our dynamic problem consists of our beliefs about the two models and beliefs about the nuisance parameters of the two models. Our “choice” set is to samp...
Acoustic Receptivity Measurements Using Modal Decomposition of a Modified Orr-Sommerfeld Equation

Boundary-layer receptivity to acoustic disturbances plays a key role in transition from laminar to turbulent flow. Acoustic disturbances interact with strong streamwise gradients at the leading edge to create Tollmien–Schlichting waves in the boundary layer. Measurement of Tollmien–Schlichting receptivity to downstream-traveling sound is complicated by the presence of Stokes waves in the boundary layer and upstream-traveling acoustic reflections that also generate downstream-traveling Tollmien–Schlichting waves. Active noise control is used to cancel reflections and enables the measurement of boundary-layer receptivity to downstream-traveling sound. Tollmien–Schlichting wave amplitudes are extracted from hot-wire data using biorthogonal decomposition of modified Orr–Sommerfeld equations that include acoustic disturbance solutions. The new method is implemented to measure the acoustic receptivity of a 20:1 modified superellipse leading edge on a flat plate. The data yield acoustic receptivity coefficients ...
Time‐resolved resonance Raman study of the spectroscopy and kinetics of the Cl−2 radical anion in aqueous solution

The resonance Raman spectrum of the chlorine molecular anion Cl−2 has been obtained using pulsed laser photolysis as a radical production method. The fundamental and nine overtone transitions are observed. Analysis of the vibrational progression gives the vibrational constants ωe =277.0±0.3 cm−1 and ωeχe =1.83±0.05 cm−1; these constants give an upper limit dissociation energy of 1.3±0.1 eV (all errors are 1σ). Time‐resolved resonance Raman spectroscopy has been employed to study the kinetics of Cl−2 disproportionation. A disproportionation rate coefficient of (11±7)×109 M−1 s−1 is obtained where the reported error includes 1σ precision and estimates of systematic errors. A resonance Raman detection limit for Cl−2 of 5×10−6 M has been obtained.
Length functions of 2-dimensional right-angled Artin groups

Morgan and Culler proved that a minimal action of a free group on a tree is determined by its translation length function. We prove an analogue of this theorem for 2-dimensional right-angled Artin groups acting on CAT(0) rectangle complexes.
A simultaneous trade model of the foreign exchange hot potato

Abstract This paper develops a simultaneous trade model of the spot foreign exchange market (cf., the sequential trade approach to dealing). The model produces hot-potato trading – a term that refers to the repeated passing of inventory imbalances between dealers. At the outset, risk-averse dealers receive customer orders that are not generally observable. Dealers then trade among themselves. Thus, each dealer intermediates both his customers' trades and any information contained therein. This information is subsequently revealed in price depending on the information in interdealer trades. We show that hot-potato trading reduces the information in interdealer trades, making price less informative.
The conjugate-gradient nonuniform fast Fourier transform (CG–NUFFT) method for one- and two-dimensional media

A novel method combining the conjugate-gradient and nonuniform fast Fourier transform (CG–NUFFT) algorithms for solving integral equations in electromagnetics is presented. The CG–NUFFT method has been applied to one- and two-dimensional inhomogeneous media. Numerical results show the advantages of the CG–NUFFT method over the CG–FFT method for problems with both electrically large and small regions. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 385–389, 2000.
THE HAWAII INFRARED PARALLAX PROGRAM. I. ULTRACOOL BINARIES AND THE L/T TRANSITION* , **

We present the first results from our high-precision infrared (IR) astrometry program at the Canada-France-Hawaii Telescope. We measure parallaxes for 83 ultracool dwarfs (spectral types M6-T9) in 49 systems, with a median uncertainty of 1.1 mas (2.3%) and as good as 0.7 mas (0.8%). We provide the first parallaxes for 48 objects in 29 systems, and for another 27 objects in 17 systems, we significantly improve upon published results, with a median (best) improvement of 1.7 times (5 times). Three systems show astrometric perturbations indicative of orbital motion; two are known binaries (2MASS J0518-2828AB and 2MASS J1404-3159AB) and one is spectrally peculiar (SDSS J0805+4812). In addition, we present here a large set of Keck adaptive optics imaging that more than triples the number of binaries with L6-T5 components that have both multi-band photometry and distances. Our data enable an unprecedented look at the photometric properties of brown dwarfs as they cool through the L/T transition. Going from Almost-Equal-To L8 to Almost-Equal-To T4.5, flux in the Y and J bands increases by Almost-Equal-To 0.7 mag and Almost-Equal-To 0.5 mag, respectively (the Y- and J-band 'bumps'), while flux in the H, K, and L' bands declines monotonically. This wavelength dependence is consistentmore » with cloud clearing over a narrow range of temperature, since condensate opacity is expected to dominate at 1.0-1.3 {mu}m. Interestingly, despite more than doubling the near-IR census of L/T transition objects, we find a conspicuous paucity of objects on the color-magnitude diagram just blueward of the late-L/early-T sequence. This 'L/T gap' occurs at (J - H){sub MKO} 0.1-0.3 mag, (J - K){sub MKO} = 0.0-0.4 mag, and implies that the last phases of cloud evolution occur rapidly. Finally, we provide a comprehensive update to the absolute magnitudes of ultracool dwarfs as a function of spectral type using a combined sample of 314 objects.« less
Institutional failure or market failure

We investigate the effect of the power of creditors, property rights protection, and institutional quality, on bank profits using a panel of 498 banks from 46 countries. Results show that better institutions and stronger property rights protection reduce bank profits, while stronger power of creditors drives up bank profits significantly. Results imply that better institutions and enhanced property rights protection lead to greater flow of credit allowing firms and investors to undertake more profitable ventures. By extension, stronger creditor rights erect steeper barriers to external finance for firms and investors. National indicators of economic freedoms may be more important to lowering the spread than strict creditor rights. Seemingly, credit markets fail when economic institutions fail or when governments intervene into these markets in ways that impede the safety and soundness of financial transactions and private contracting.
The Chastain effect: Using Title IX to measure the causal effect of participating in high school sports on adult women's social lives

Abstract Many studies have sought to estimate the effects of participating in sports on ex-athletes’ adult lives. This paper contributes to the existing literature in two ways. First, it adopts an instrumental-variables method pioneered by Betsey Stevenson (2010) in which variation in rates of boys’ athletic participation across states before the passage of Title IX is used to instrument for changes in girls’ athletic participation following its passage, thereby avoiding selection bias and allowing for causal estimates. Second, it looks at the effect of participating in sports not on economic, but on social outcomes. In particular, we find that a ten percentage-point increase in state-level female sports participation generates a five to six percentage-point rise in the rate of female secularism, a five percentage-point increase in the proportion of women who are mothers, and a six percentage-point rise in the proportion of mothers who, at the time that they are interviewed, are single mothers. While our results appear to paint a picture of independence from potentially patriarchal institutions (church and marriage), further research is necessary to understand whether our results can be attributed to a single story such as this one or whether they are the products of multiple causal mechanisms.
Poincaré Semigroup Symmetry as an Emergent Property of Unstable Systems

The notion that elementary systems correspond to irreducible representations of the Poincare group is the starting point for this paper, which then goes on to discuss how a semigroup for the time evolution of unstable states and resonances could emerge from the underlying Poincare symmetry. Important tools in this analysis are the Clebsch-Gordan coefficients for the Poincare group.
Efficient construction of 6-azasteroids : Dual inhibitors of steroidal 5α-reductase

A new route to 17 beta-substituted-6-azaandrost-4-en-3-ones, potent dual inhibitors of type 1 and 2 steroidal 5 alpha-reductase, is described.
Synthesis of some derivatives of 6-amino-1,5-anhydro-6-deoxy-D-glucitol and 2-amino-1,5-anhydro-2-deoxy-D-glucitol.

Abstract 6-Amino-1,5-anhydro-6-deoxy- d -glucitol (11) was prepared from 2,3,4,6-tetra-O-acetyl-α- d -glucopyranosyl bromide (1) in six steps. Reduction of 1 with tributyltin hydride, followed by deacetylation, monomolar tosylation, and reacetylation, afforded 2,3,4-tri-O-acetyl-1,5-anhydro-6-O-toluene-p-sulfonyl- d -glucitol (9). Alternatively, tritylation of 1,5-anhydro- d -glucitol, followed by acetylation, detritylation, and tosylation, gave 9. Mesylation gave 8. Treatment of 8 or 9 with azide anion afforded the azide 10, reduction of which with tributyltin hydride gave 11, which was mesylated or tosylated, and then deacetylated to give the 6-methane-sulfonamido or 6-toluene-p-sulfonamido derivative. Similarly, mesylation or tosylation of 3,4,6-tri-O-acetyl-2-amino-1,5-anhydro-2-deoxy- d -glucitol (20) gave the 2-methanesulfonamido or 2-toluene-p-sulfonamido derivatives. Treatment of 11 and 20 with sulfur trioxide-pyridine afforded the sulfoamino derivatives, deacetylation of which gave sugar analogs of cyclamate-like compounds.
RESOLVED SUBMILLIMETER OBSERVATIONS OF THE HR 8799 AND HD 107146 DEBRIS DISKS

We present 880 {mu}m Submillimeter Array observations of the debris disks around the young solar analog HD 107146 and the multiple-planet host star HR 8799, at an angular resolution of 3'' and 6'', respectively. We spatially resolve the inner edge of the disk around HR 8799 for the first time. While the data are not sensitive enough (with rms noise of 1 mJy) to constrain the system geometry, we demonstrate that a model by Su et al. based on the spectral energy distribution (SED) with an inner radius of 150 AU predicts the spatially resolved data well. Furthermore, by modeling simultaneously the SED and visibilities, we demonstrate that the dust is distributed in a broad (of order 100 AU) annulus rather than a narrow ring. We also model the observed SED and visibilities for the HD 107146 debris disk and generate a model of the dust emission that extends in a broad band between 50 and 170 AU from the star. We perform an a posteriori comparison with existing 1.3 mm CARMA observations and demonstrate that a smooth, axisymmetric model reproduces all of the available millimeter-wavelength data well.
AB INITIO EQUATION OF STATE FOR HYDROGEN-HELIUM MIXTURES WITH RECALIBRATION OF THE GIANT-PLANET MASS-RADIUS RELATION

Using density functional molecular dynamics simulations, we determine the equation of state (EOS) for hydrogen-helium mixtures spanning density-temperature conditions typical of giant-planet interiors, {approx}0.2-9 g cm{sup -3} and 1000-80,000 K for a typical helium mass fraction of 0.245. In addition to computing internal energy and pressure, we determine the entropy using an ab initio thermodynamic integration technique. A comprehensive EOS table with 391 density-temperature points is constructed and the results are presented in the form of a two-dimensional free energy fit for interpolation. Deviations between our ab initio EOS and the semi-analytical EOS model by Saumon and Chabrier are analyzed in detail, and we use the results for initial revision of the inferred thermal state of giant planets with known values for mass and radius. Changes are most pronounced for planets in the Jupiter mass range and below. We present a revision to the mass-radius relationship that makes the hottest exoplanets increase in radius by {approx}0.2 Jupiter radii at fixed entropy and for masses greater than {approx}0.5 Jupiter mass. This change is large enough to have possible implications for some discrepant ''inflated giant exoplanets''.
Dislocation motion around loaded notches in ice single-crystals

Abstract Synchrotron X-ray topography has been used to study dislocation behavior around notches in single-crystals of ice during in-situ deformation at a constant strain-rate. During deformation at −8°C a dislocation-depleted zone (DDZ) formed above the notch while a vertical array of dislocations formed below the notch. Modeling the interaction between basal plane dislocation loops and the notch stress field suggested that this DDZ arose from dislocations gliding completely through the specimen. Dislocation activity around the notch at −8°C was much greater than that observed at −40°C and −60°C.
Debtors’ prisons in America: An economic analysis

Abstract Debtors’ prisons have been commonplace throughout history, including in the United States. While imprisonment for debt no doubt elicited some repayment by benefactors of the debtor, we argue that its primary function was to deter default in the first place by giving borrowers an incentive to disclose hidden assets. Because of its cost, however, imprisonment was destined to be replaced by more efficient ways of preventing borrowers from sheltering assets. Empirical analysis of state laws banning imprisonment for debt provides some support for this argument. In particular, the results suggest that states in which the publishing industry developed sooner (thus facilitating the flow of information) were more likely to enact early bans on imprisonment for debt.
Studies towards the total synthesis of halichlorine: asymmetric synthesis of the spiroquinolizidine subunit

Abstract The C1–C15 spiroquinolizidine subunit (cf. 2 ) of the marine natural product halichlorine ( 1 ) was prepared in 12 steps starting from the known ‘Meyers-lactam’ 5 . The synthesis involves a B -alkyl-Suzuki coupling followed by a highly stereoselective intramolecular Michael addition and an intramolecular Mannich ring closure.
Crystals and total positivity on orientable surfaces

We develop a combinatorial model of networks on orientable surfaces, and study weight and homology generating functions of paths and cycles in these networks. Network transformations preserving these generating functions are investigated. We describe in terms of our model the crystal structure and R-matrix of the affine geometric crystal of products of symmetric and dual symmetric powers of type A. Local realizations of the R-matrix and crystal actions are used to construct a double affine geometric crystal on a torus, generalizing the commutation result of Kajiwara et al. (Lett Math Phys, 60(3):211–219, 2002) and an observation of Berenstein and Kazhdan (MSJ Mem, 17:1–9, 2007). We show that our model on a cylinder gives a decomposition and parametrization of the totally non-negative part of the rational unipotent loop group of GLn.
The Dirac monopole and differential characters

We describe the Dirac monopole using the Cheeger–Simons differential characters. We comment on the role of the Dirac string and on the connection with Deligne cohomology.
A Search for Diffuse Interstellar Features in Stars with Circumstellar Dust Shells

We have searched for diffuse features at λ 4430, 5780 and 6613 in the spectra of 17 stars which show infra-red excesses or other grounds for believing that they have dusty envelopes. In no case could we identify diffuse bands that may be ascribed to the circumstellar envelope. We conclude that the grains in circumstellar envelopes are not identical with the grains in the general interstellar medium.
SoftCast: Clean-slate scalable wireless video

Video broadcast and mobile video challenge the conventional wireless design. In broadcast and mobile scenarios the bit rate supported by the channel differs across receivers and varies quickly over time. The conventional design however forces the source to pick a single bit rate and degrades sharply when the channel cannot not support the chosen bit rate. This paper presents an overview of SoftCast, a clean-slate design for wireless video where the source transmits one video stream that each receiver decodes to a video quality commensurate with its specific instantaneous channel quality. To do so, SoftCast ensures the samples of the digital video signal transmitted on the channel are linearly related to the pixels' luminance. Thus, when channel noise perturbs the transmitted signal samples, the perturbation naturally translates into approximation in the original video pixels. Hence, a receiver with a good channel (low noise) obtains a high fidelity video, and a receiver with a bad channel (high noise) obtains a low fidelity video.
Institutional and environmental aspects of geothermal energy development

Until recently, the majority of work in geothermal energy development has been devoted to technical considerations of resource identification and extraction technologies. The increasing interest in exploiting the variety of geothermal resources has prompted an examination of the institutional barriers to their introduction for commercial use. A significant effort was undertaken by the Jet Propulsion Laboratory as a part of a national study to identify existing constraints to geothermal development and possible remedial actions. These aspects included legislative and legal parameters plus environmental, social, and economic considerations.
Estimating clear-day solar radiation: An evaluation of three models

Abstract Three models for estimating clear-day solar radiation were compared to one another and to values of solar radiation measured at Ft Collins, Colo. The models of Campbell (1977), Gates (1962) and McCullough and Porter (1971) all correlate closely with measurements of clear-day solar radiation. The Campbell and the Gates models require less technical expertise and less expensive computations to produce estimates of the direct component of solar radiation. All of the models appear to require calibration in order to correct estimates of the input variables to measured values of irradiance so that accurate calculations of direct solar radiation can subsequently be made. The best estimates of the diffuse component of solar radiation are obtained from the model of McCullough and Porter. The easiest and most accurate predictions of total solar radiation can be obtained from the direct-radiation models of Campbell (1977) and Gates (1962) and a modification of the diffuse-component model of McCullough and Porter (1971).
Measurement of peak temperature along an optical fiber

A multimode silica-clad optical fiber with a liquid silicone core was used as a distributed-line peak-temperature sensor over a temperature range from ambient to 190°C. The maximum error was 2°C and was essentially independent of the length or position of the hot zone.
Mandatory, Preferred, or Discretionary: How the Classification of Domestic Violence Warrantless Arrest Laws Impacts Their Estimated Effects on Intimate Partner Homicide

Warrantless arrest laws for domestic violence (DV) are generally classified as discretionary, preferred, or mandatory, based on the level of power accorded to police in deciding whether to arrest. However, there is a lack of consensus in the literature regarding how each state's law should be categorized. Using three classification schemes, this study examined whether variations among these schemes impact research outcomes by analyzing the effects of discretionary, preferred, and mandatory warrantless arrest laws on intimate partner homicide (IPH). Variations in classification schemes and in the dates of law passage presented in the literature resulted in differing estimated effects of the laws.
Are two heads better than one? Monetary policy by committee

Two experiments were conducted to test the common hypothesis that groups make decisions more slowly than individuals. One of these experiments imitates real-life monetary policy decisions. In both cases, the hypothesis is found wanting: groups are not slower than individuals. In both experiments, we also find that group decisions are on average better than individual decisions. This holds regardless of whether the groups make decisions by unanimity or majority rule. Simple mechanical theories of group decisionmaking— that the group follows its average player, median player, or best player—do not explain the results. Group interactions seem to matter.
A Centrally Symmetric Version of the Cyclic Polytope

We define a centrally symmetric analogue of the cyclic polytope and study its facial structure. We conjecture that our polytopes provide asymptotically the largest number of faces in all dimensions among all centrally symmetric polytopes with n vertices of a given even dimension d=2k when d is fixed and n grows. For a fixed even dimension d=2k and an integer 1≤j 0 and at most $(1-2^{-d}+o(1)){n\choose j+1}$ as n grows. We show that c1(d)≥1−(d−1)−1 and conjecture that the bound is best possible.
The present status of the treatment of toxic goiter.

THIS paper presents a brief summary of the various methods of treatment of toxic goiter that are available at the present time and the current attitude toward them. Until a few years ago it was generally agreed that the best method of treatment was a subtotal thyroidectomy after adequate preoperative preparation with iodine, a high-caloric diet and rest. Various details had been perfected so much that the mortality from surgical procedures had dropped to about 1 per cent in leading clinics. In the past few years treatment has been greatly modified by the use of antithyroid drugs and radioactive iodine. There are five methods of treatment available at the present time: 1. A subtotal thyroidectomy after adequate preoperative preparation with propylthiouracil, iodine and a high-caloric diet. 2. Medical management with antithyroid drugs. 3. Medical management with radioactive iodine. 4. Roentgen ray treatment of the thyroid. 5. Roentgen ray treatment of the pituitary. SUBTOTAL THYROIDECTOMY AFTER ADEQUATE PRE...
Synthetic studies on tetrazomine: lipase PS resolution of racemic cis-β-hydroxypipecolic acid

Abstract An efficient enzymatic resolution of racemic cis -β-hydroxypipecolic acid is described affording both the (2 S ,3 R ) and (2 R ,3 S ) protected amino acids in good yield and high enantiomeric ratios.
Replication attack on random key pre-distribution schemes for wireless sensor networks

When setting up a sensor network, one of the first requirements is to establish cryptographic keys for later use. However, the traditional key establishment techniques cannot be directly applied due to the inherent properties of sensor networks. Recently, a promising methodology, random key pre-distribution schemes based on symmetric cryptography, has been proposed. In this paper, we study the problem of replication attack on random key pre-distribution schemes. Using a combination of modeling, analysis, and experiments, we analyze, characterize, and discuss the relationship among the replicated hostile nodes, the sensor networks, and the resiliency of various random key pre-distribution schemes against replication attack. Example findings include: (1) the sensor networks with random key pre-distribution schemes, even with one replicated sensor, start to become almost 100% insecure when the adversary captures and stores the key information equivalent to those carried by one good sensor node; and (2) when the replicated node has less memory to store key information than the original node, among the proposed schemes, the q-composite scheme with larger q is most resilient against replication attack while the basic scheme is least resilient and the Blom-based scheme lies in between the above two schemes. Interestingly, it is the other way round when the replicated node has more memory to store key information than the original node. Moreover, as a transition, the resilience against replication attack is the same for all the random schemes when the replicated and original nodes have the same memory to store key information. This study not only provides practical insights into the design of more secure and efficient key establishment schemes allowing simple key establishment for large-scale sensor networks, but can also be used to predict the payoff that an adversary can gain after injecting a certain number of nodes into the sensor networks.
Design and synthesis of novel χ2-constrained phenylalanine, naphthylalanine, and tryptophan analogues and their use in biologically active melanotropin peptides

A series of novel hydrophobic, bulky χ2-constrained phenylalanine, naphthylalanine, and tryptophan derivatives was designed and synthesized. The key steps involved asymmetric hydrogenations of α-enamides using Burk's DuPHOS-based Rh(I) catalysts to give high enantiomerically pure α-amino acid derivatives. The subsequent Suzuki cross couplings of the amino acid analogues with boronic acid derivatives afforded these aromatic substituted amino acids in high yields and with high enantioselectivity. The incorporation of these novel χ2-constrained amino acids into peptides and peptidomimetics provides fruitful information in the development of peptide and peptidomimetic ligands of melanotropins and an understanding of the interactions between ligands and receptors/acceptors.
On the vibronic theory of resonance Raman scattering

Abstract Resonance Raman excitation profiles of totally symmetric vibrational modes are investigated using a model that analytically includes the complete subspace of Franck-Condon active vibrations associated with each intermediate electronic state. This model is used to fit data obtained in resonance with the Soret band of cytochrome c. The excitation profiles are asymmetric and peak distinctively to the blue of the Soret absorption maximum. Large damping factors and/or inhomogeneous site distributions by themselves cannot account for the observed data. The theoretical results imply that the excited state lifetime associated with the Soret band of ferrocytochrome c has a lower limit on the order of 50 fs and that, compared to the ferrous form, the ferric cytochrome has a larger x-y splitting and a shorter lifetime. In constrast to the large multidimensional heme system, we also present the results of a simple model calculation applicable to smaller molecules. A two dimensional subspace is explored, where Raman Franck-Condon (RFC) and Franck-Condon (FC) factors are calculated for different potential energy surface parameters. Under certain conditions the RFC based scattering profiles of one vibration are strongly coupled to the FC based behaviour of the other vibration. Rather complex profiles are then predicted even for the simple two- dimensional case.
Progesterone withdrawal as the lactogenic trigger in the rat.

Lactogenesis, as indicated by the appearance of mammary lactose, follows ovariectomy and/or hysterectomy and the fall in the concentration of progesterone in the plasma preceding normal parturition in the pregnant rat. It is suppressed by administered progesterone in all cases, and by prolactin after hysterectomy. The natural lactogenic signal may occur 30 hr. before parturition, due to conversion of progesterone to 20α-hydroxypregn-4-en-3-one in the ovaries. Changes in the concentration of corticosterone, oestrogen and prolactin in the plasma either do not occur or do not constitute a lactogenic signal.
Central derivatives of L-functions in Hida families

We prove a result of the following type: given a Hida family of modular forms, if there exists a weight two form in the family whose L-function vanishes to exact order one at s = 1, then all but finitely many weight two forms in the family enjoy this same property. The analogous result for order of vanishing zero is also true, and is an easy consequence of the existence of the Mazur–Kitagawa two-variable p-adic L-function.
Lengths of finite dimensional representations of PBW algebras

Abstract Let Σ be a set of n × n matrices with entries from a field, for n > 1, and let c(Σ) be the maximum length of products in Σ necessary to linearly span the algebra it generates. Bounds for c(Σ) have been given by Paz and Pappacena, and Paz conjectures a bound of 2n − 2 for any set of matrices. In this paper we present a proof of Paz’s conjecture for sets of matrices obeying a modified Poincare–Birkhoff–Witt (PBW) property, applicable to finite dimensional representations of Lie algebras and quantum groups. A representation of the quantum plane establishes the sharpness of this bound, and we prove a bound of 2n − 3 for sets of matrices with this modified PBW property which do not generate the full algebra of all n × n matrices. This bound of 2n − 3 also holds for representations of Lie algebras, although we do not know whether it is sharp in this case.
ECONOMIC RATIONALITY AND THE AREEDA-TURNER RULE

The Areeda–Turner rule in U.S. antitrust jurisprudence limits successful predatory pricing cases to circumstances where prices can be shown to have been set below marginal costs. While not cast so, the rule reflects the view that predatory pricing is rarely attempted; and even where attempted is rarely successful; and even where attempted and successful, is difficult to identify. In this paper, we examine the theoretical and empirical foundations of this rule, and conclude that it is time to demote the Areeda–Turner analysis from the status of a rule to that of a potentially useful form of inquiry in predatory pricing litigation, but one which is neither necessary nor dispositive.
Image Encryption using the Sudoku Matrix

This paper introduces a new effective and lossless image encryption algorithm using a Sudoku Matrix to scramble and encrypt the image. The new algorithm encrypts an image through a three stage process. In the first stage, a reference Sudoku matrix is generated as the foundation for the encryption and scrambling processes. The image pixels' intensities are then changed by using the reference Sudoku matrix values, and then the pixels' positions are shuffled using the Sudoku matrix as a mapping process. The advantages of this method is useful for efficiently encrypting a variety of digital images, such as binary images, gray images, and RGB images without any quality loss. The security keys of the presented algorithm are the combination of the parameters in a 1D chaotic logistic map, a parameter to control the size of Sudoku Matrix and the number of iteration times desired for scrambling. The possible security key space is extremely large. The principles of the presented scheme could be applied to provide security for a variety of systems including image, audio and video systems.
The Synthesis and Crystal Structure of U7O2Se12

The new compound U7O2Se12 was synthesized at 1173 K as a result of both unintentional and intentional oxygen contamination. The composition balances with formal charges of +4, –2, and –2 for U, O, and Se, respectively. U7O2Se12 crystallizes with one formula unit in space group C-P of the hexagonal system in a cell of dimensions a = 11.3222(4) A, c = 4.1362(1) A. The structure of U7O2Se12 closely resembles that of the An7Te12 (An = Th, U) compounds, but contains cavities, in which oxygen atoms are coordinated to three uranium atoms in a trigonal planar arrangement. It is not known if other members of the An7Q12 family (An = Th, U; Q = S, Se, Te) are actually An7O2Q12 compounds.
Dark matter signals from cascade annihilations

A leading interpretation of the electron/positron excesses seen by PAMELA and ATIC is dark matter annihilation in the galactic halo. Depending on the annihilation channel, the electron/positron signal could be accompanied by a galactic gamma ray or neutrino flux, and the non-detection of such fluxes constrains the couplings and halo properties of dark matter. In this paper, we study the interplay of electron data with gamma ray and neutrino constraints in the context of cascade annihilation models, where dark matter annihilates into light degrees of freedom which in turn decay into leptons in one or more steps. Electron and muon cascades give a reasonable fit to the PAMELA and ATIC data. Compared to direct annihilation, cascade annihilations can soften gamma ray constraints from final state radiation by an order of magnitude. However, if dark matter annihilates primarily into muons, the neutrino constraints are robust regardless of the number of cascade decay steps. We also examine the electron data and gamma ray/neutrino constraints on the recently proposed ``axion portal'' scenario.