cssi/SciSciGPT-SciSciNet huggingface dataset:
Nucleosynthetic Constraints on the Mass of the Heaviest Supernovae

We explore the sensitivity of nucleosynthesis in massive stars to the truncation of supernova explosions above a certain mass. It is assumed that stars of all masses contribute to nucleosynthesis by their pre-explosive winds, but above a certain limiting main sequence mass, M BH, the presupernova star becomes a black hole and ejects nothing more. The solar abundances from oxygen to atomic mass 90 are fit quite well assuming no cutoff at all, i.e., by assuming all stars up to 120 M ☉ make successful supernovae. Little degradation in the fit occurs if M BH is reduced to 25 M ☉. If this limit is reduced further however, the nucleosynthesis of the s-process declines precipitously and the production of species made in the winds, e.g., carbon, becomes unacceptably large compared with elements made in the explosion, e.g., silicon and oxygen. By varying uncertain physics, especially the mass loss rate for massive stars and the rate for the 22Ne(α, n)25Mg reaction rate, acceptable nucleosynthesis might still be achieved with a cutoff as low as 18 M ☉. This would require, however, a supernova frequency three times greater than the fiducial value obtained when all stars explode in order to produce the required 16O. The effects of varying M BH on the nucleosynthesis of 60Fe and 26Al, the production of helium as measured by ΔY/ΔZ, and the average masses of compact remnants are also examined.
A Quasi-Convex Optimization Approach to Parameterized Model Order Reduction

In this paper, an optimization-based model order reduction (MOR) framework is proposed. The method involves setting up a quasi-convex program that solves a relaxation of the optimal Hinfin norm MOR problem. The method can generate guaranteed stable and passive reduced models and is very flexible in imposing additional constraints such as exact matching of specific frequency response samples. The proposed optimization-based approach is also extended to solve the parameterized model-reduction problem (PMOR). The proposed method is compared to existing moment matching and optimization-based MOR methods in several examples. PMOR models for large RF inductors over substrate and power-distribution grid are also constructed.
Synthesis of a phosphoramidite of 2′-deoxy-5,6-dihydro-5-azacytidine. Its potential application in the synthesis of DNA containing dihydro-5-aza-and 5-azacytosine bases.

Abstract A novel phosphoramidite ( 9 ) has been synthesized and shown to be an efficient coupling reagent for the synthesis of oligonucleotide fragments containing the modified base 5,6-dihydro-5-azacytosine. With a model dihydro-5-azacytosine/thymine dimer ( 12 ), oxidation of the dihydrotriazine ring to the aromatic base was partially successful.
Microlocal analysis of scattering data for nested conormal potentials

Consider the potential scattering problem for the wave equation: $$\begin{array}{rcl} & & ({\partial }_{t}^{2} -\bigtriangleup + q)u = 0\text{ in }{\mathbb{R}}^{n} \times \mathbb{R} \\ & & u = \delta (t - x \cdot \omega )\text{ for }t << -\rho,\end{array}$$ (1) where q is a compactly supported potential and \(\omega \in {S}^{n-1}\) is fixed. Here ρ is the value such that \(supp(q) \subset \{\vert x\vert \leq \rho \}\).
Impulsive pump-probe and photon-echo spectroscopies of dye molecules in condensed phases.

A theory for impulsive resonant pump-probe and photon-echo spectroscopies of polyatomic dyes in solution is developed. A multimode calculation in which the intramolecular and solvation modes are modeled as Brownian oscillators is presented. Electronic dephasing, the time-dependent Stokes shift, and quantum beats are analyzed.
Directly connecting the very long baseline array

At present, the signals received by the 10 antennas of the Very Long Baseline Array (VLBA) are recorded on instrumentation tapes. These tapes are then shipped from the antenna locations - distributed across the mainland USA, the US Virgin Islands, and Hawaii - to the processing center in Socorro, New Mexico. The Array operates today at a mean sustained data rate of 128 Mbps per antenna, but peak rates of 256 Mbps and 512 Mbps are also used. Transported tapes provide the cheapest method of attaining these bit rates. The present tape system derives from wideband recording techniques dating back to the late 1960s, and has been in use since the commissioning of the VLBA in 1993. It is in need of replacement on a time scale of a few years. Further, plans are being developed which would increase the required data rates to 1 Gbps in 5 years and 100 Gbps in 10 years. With the advent of higher performance networks, it should be possible to transmit the data directly to the processing center. However, achieving this connectivity is complicated by the remoteness of the antennas -
GEO Orbit Determination via Covariance Analysis with a Known Clock Error

ABSTRACT: Geostationary earth orbit (GEO) satellites serve as relays to transmit messages for space-based augmentation systems (SBASs). GEOs can act as ranging sources for SBAS users as well, adding to the availability and continuity of a number of SBAS services. The SBAS determines the GEO orbit error from covariance analysis of satellite dynamics and station-to-satellite geometry. However, separating the orbit determination errors from the clock errors is difficult, and GEO range errors tend to be much larger than GPS range errors. This paper proposes a technique for making the clock state of a “bent-pipe” GEO a known quantity, then considers the effect on the derived GEO range through a simulation of the orbit determination extended Kalman filter. The study indicates that this technique reduces the GEO orbit error by a factor of ˜22 and implies that GEO orbit determination errors can be made comparable to those of GPS satellites.
Multi-energy gamma-ray automated scanning system

Abstract A CAMAC-based gamma-ray scanning system was used to measure the transmission through stacked attenuators for up to 16 different gamma rays. For each measurement, we obtained the transmission for gamma rays ranging in energy from 77 to 2614 keV. These transmission measurements were used to produce a set of linear equations that may be solved for either thickness or density of the discrete attenuators comprizing a given stacked assembly.
Unified BCS-like model of pairing and alpha-correlations

We construct a BCS-like model that combines nucleonic pairing correlations and possible quartic correlations of alpha-type in a single variational wave function and derive corresponding gap equations. In the approximation of large logarithms typical for the BCS approach, we show that the system reveals two possible types of a condensate which cannot coexist. If the alpha-type condensate prevails at N = Z, the growth of the neutron excess will naturally lead to the first order phase transition to the nucleon condensates.
Experiments at The Virtual National Laboratory for Heavy Ion Fusion

Abstract An overview of experiments is presented, in which the physical dimensions, transverse emittance and generalized perveance are scaled to explore driver-relevant beam dynamics. Among these are beam merging, focusing to a small spot, and bending and recirculating beams. The Virtual National Laboratory for Heavy Ion Fusion (VNL) is also developing two driver-scale beam experiments involving heavy-ion beams with I beam ∼1 A to provide guidance for the design of an Integrated Research Experiment (IRE) for driver system studies within the next 5 years. Multiple-beam sources and injectors are being designed and a one-beam module will be built and tested. Another experimental effort will be the transport of such a beam through ∼100 magnetic quadrupoles. The experiment will determine transport limits at high aperture fill factors, beam halo formation, and the influence on beam properties of secondary electron production and neutral atom desorption from the vacuum pipe wall. Research into driver technology will be briefly presented, including the development of ferromagnetic core materials, induction core pulsers, multiple-beam quadrupole arrays and plasma channel formation experiments for pinched transport in reactor chambers.
Babinet's principle for an anisotropic resistive surface using different approaches

Extension of Babinet's principle in electromagnetic theory to an inhomogeneous anisotropic (with non-zero off-diagonal terms) resistive sheet is made. Different methods are employed for this purpose so that a better understanding can be gained. Some basic properties of electromagnetic waves, such as their odd and even symmetry, are also reviewed for clarity of presentation. Some errors in previously published results are also corrected.
Circular dichroism of the benzene group vibrations and molecular stereochemistry

Circular dichroism (CD) in the vibrational transitions of three different series of molecules-namely, phenylcarbinols, carboxylic acids, and oxiranes-containing the benzene group is measured. It is found that a benzene-group vibration, where the hydrogen atoms in the meta and para positions vibrate in a concerted semicircular path, gives rise to CD that is consistent with the molecular stereochemistry. This observation provides a practical approach to the use of the benzene group as a probe of molecular chirality.
Scheduling data transfers in a network and the set scheduling problem

In this paper we consider the online ftp problem. The goal is to service a sequence of file transfer requests given bandwidth constraints of the underlying communication network. The main result of the paper is a technique that leads to algorithms that optimize several natural metrics, such as max-stretch, total flow time, max flow time, and total completion time. In particular, we show how to achieve optimum total flow time and optimum max-stretch if we increase the capacity of the underlying network by a logarithmic factor. We show that the resource augmentation is necessary by proving polynomial lower bounds on the max-stretch and total flow time for the case where online and offline algorithms are using same-capacity edges. Moreover, we also give polylogarithmic lower bounds on the resource augmentation factor necessary in order to keep the total flow time and max-stretch within a constant factor of optimum.
Terrestrial kilometric radiation, 3. Average spectral properties

A study is presented of the average spectral properties of terrestrial kilometric radiation (TKR) derived from observations made by radio astronomy experiments onboard the IMP-6 and RAE-2 spacecraft. As viewed from near the equatorial plane, TKR is most intense and most often observed in the 21-24 hr local time zone and is rarely seen in the 09-12 hr zone. The peak flux density usually occurs near 240 kHz, but there is evidence that the peak occurs at a somewhat lower frequency on the dayside. The frequency of the peak in the average flux spectrum varies inversely with increasing substorm activity as inferred from the auroral electrojet index (AE) from a maximum near 300 kHz during very quiet times to a minimum below 200 kHz during very disturbed times. The absolute flux levels in the 100-600 kHz TKR band increase significantly with increasing AE. The average power associated with a particular source region seems to decrease rapidly with increasing source altitude.
The pin redistribution problem in multi-chip modules

We introduce thepin redistribution problem (PRP), which arises from layout design ofmulti-chip modules. The problem is to redistribute the pins uniformly over the MCM substrate using a number of pin redistribution layers. Pin redistribution is very important in MCM design because it has been used to not only provide a minimum spacing between signal wires in dense signal distribution layers, but also provide engineering change capability [3, 4]. Moreover, our experience [10] showed that the capacitive coupling noise between vias (one of the major problems in designing MCMs) induced by many layers (up to 63 layers) can be reduced using the pin redistribution technique. The goal of the problem is to minimize the number of layers required to redistribute the entire set. As a net is undefined, a number of challenging issues arise. Three effective approaches are proposed for solving this problem.
Glyco-S-nitrosothiols, a novel class of NO donor compounds

Abstract Three novel glyco- S -nitrosothiol NO donor compounds 1, 2 , and 3 have been synthesized. These compounds outperform S -nitroso- N -acetylpenicillamine (SNAP) in aqueous solubility and stability, with and without EDTA and in the presence or absence of Cu 2+ .
On Some Properties of Permutation Tableaux

We consider the relations between various permutation statistics and properties of permutation tableaux. We answer some of the open problems of Steingrimsson and Williams [8], in particular, on the distribution of the bistatistic of numbers of rows and essential ones in permutation tableaux. We also consider and enumerate sets of permutation tableaux related to some pattern restrictions on permutations.
The role of thermal conductivity in the pulsed laser damage sensitivity of optical thin films

Abstract Pulsed-laser-induced damage of optical thin films is, in general, initiated by the absorption of laser radiation by imperfections in the films or at interfaces between film layers and/or the substrate. A heat flow analysis of this process stresses the importance that the thermal conductivity of both the thin film host and the substrate play in establishing the laser-induced damage threshold. Unfortunately, recent work which will be reviewed in this presentation indicates that the thermal conductivity of thin films can be several orders of magnitude lower than that of a corresponding material in bulk form as a consequence of the film structure which results principally from the deposition process. The importance of thermal conductivity will be related to parameters such as absorption mechanisms, film materials, composition and other variables. Its implication for the ultimate optical strength of materials and the direction in which thin film research and processing should proceed will be highlighted.
Cyclotron resonance in a nonneutral plasma

Single-component plasmas are found to exhibit a reversal in the roles of cyclotron and upper hybrid resonances familiar in neutral plasmas. There is a global resonance at the cyclotron frequency $\ensuremath{\omega}=\ensuremath{\Omega}\ensuremath{\equiv}\frac{\mathrm{qB}}{\mathrm{mc}}$ and a local field cancellation at layers where $\ensuremath{\omega}={\ensuremath{\Omega}}_{1}={({\ensuremath{\Omega}}^{2}\ensuremath{-}{\ensuremath{\omega}}_{p}^{2})}^{\frac{1}{2}}$, ${\ensuremath{\omega}}_{p}$ being the local plasma frequency. Thermal effects limit the amplitude of the global resonance and produce energy absorption at the $\ensuremath{\omega}={\ensuremath{\Omega}}_{1}$ layers.
Understanding chiral symmetry breaking with the overlap action

Abstract A chiral fermion action allows one to do very clean studies of chiral symmetry breaking in QCD. I will briefly describe how to compute with the overlap action (relatively) cheaply, and then turn to physics: Low modes of the Dirac operator show a “lumped” chiral density which peaks at the locations of instantons and anti-instantons. These modes dominate correlation functions at small quark mass in many channels. The picture qualitatively (and in some cases quantitatively) resembles an instanton liquid model.
Probing Cosmology with the X-Ray Forest

There is a growing consensus that in the present universe most baryons reside in galaxy clusters and groups in the form of highly ionized gas at temperatures of 106-108 K. The H-like and He-like ions of the heavy elements can produce absorption features—the so-called X-ray forest—in the X-ray spectrum of a background quasar. We investigate the distribution of the X-ray absorption lines produced by this gas under three different cosmological models: the standard cold dark matter model with Ω0 = 1, a flat model with Ω0 = 0.3, and an open model with Ω0 = 0.3. We give a semianalytic calculation of the X-ray forest distribution based on the Press-Schechter formalism, following Perna & Loeb (1998). We choose three ions (O VIII, Si XIV, and Fe XXV) and calculate the distribution functions, the number of absorbers along the line of sight (LOS) to a distant quasar versus redshift, and column density in a given ion. We find significant differences in the evolution of the distribution functions among the three cosmological models. Using Monte Carlo simulations, we simulate the distribution of X-ray absorption lines for 10,000 random LOS. We find that there are at least several O VIII lines with column density higher than 1016 cm-2. Finally, we explore the possibility of detecting the X-ray forest with current and upcoming X-ray missions, and we present an XMM Reflection Grating Spectrometer (RGS) simulation of a representative quasar X-ray spectrum.
Heavy squarks at the LHC

The LHC, with its seven-fold increase in energy over the Tevatron, is capable of probing regions of SUSY parameter space exhibiting qualitatively new collider phenomenology. Here we investigate one such region in which first generation squarks are very heavy compared to the other superpartners. We find that the production of these squarks, which is dominantly associative, only becomes rate-limited at $ {m_{\tilde{q}}} \gtrsim 4(5)\;{\text{TeV}} $ for $ \mathcal{L}\sim 10\left( {100} \right)\;{\text{f}}{{\text{b}}^{ - 1}} $ . However, discovery of this scenario is complicated because heavy squarks decay primarily into a jet and boosted gluino, yielding a dijet-like topology with missing energy (MET) pointing along the direction of the second hardest jet. The result is that many signal events are removed by standard jet/MET anti-alignment cuts designed to guard against jet mismeasurement errors. We suggest replacing these anti-alignment cuts with a measurement of jet substructure that can significantly extend the reach of this channel while still removing much of the background. We study a selection of benchmark points in detail, demonstrating that $ {m_{\tilde{q}}} = 4(5) \ {\rm TeV}$ first generation squarks can be discovered at the LHC with $ \mathcal{L}\sim 10\left( {100} \right)\;{\text{f}}{{\text{b}}^{ - 1}} $ .
Spectral measures and Cuntz algebras

We consider a family of measures $\mu$ supported in $\br^d$ and generated in the sense of Hutchinson by a finite family of affine transformations. It is known that interesting sub-families of these measures allow for an orthogonal basis in $L^2(\mu)$ consisting of complex exponentials, i.e., a Fourier basis corresponding to a discrete subset $\Gamma$ in $\br^d$. Here we offer two computational devices for understanding the interplay between the possibilities for such sets $\Gamma$ (spectrum) and the measures $\mu$ themselves. Our computations combine the following three tools: duality, discrete harmonic analysis, and dynamical systems based on representations of the Cuntz $C^*$-algebras $\mathcal O_N$.
The Reality of Virtual Reality: Second Life as a Tool for Online Peer-Teaching Activities

In order to improve teacher preparation courses offered online, a study of the use of Second Life virtual world for peer-teaching activities was conducted. The research period was over one year and the sampling group consisted of 25 Teaching English as a Second Language (TESL) students. The methods practiced during the study follow the suggestions and implications given in previous research in hopes that an informed design would be the means to overcome the published limitations of Second Life. Despite this, the authors were not able to overcome previous difficulties, and did not find Second Life to be useful as a tool for classroom role-playing in online teacher-development courses. Virtual reality, however, has promise for facilitating teacher development; thus, further investigation is needed to find an appropriate virtual venue for this purpose.
Control of 1,3-Cyclohexadiene Photoisomerization Using Light-Induced Conical Intersections

We have studied the photoinduced isomerization from 1,3-cyclohexadiene to 1,3,5-hexatriene in the presence of an intense ultrafast laser pulse. We find that the laser field maximally suppresses isomerization if it is both polarized parallel to the excitation dipole and present 50 fs after the initial photoabsorption, at the time when the system is expected to be in the vicinity of a conical intersection that mediates this structural transition. A modified ab initio multiple spawning (AIMS) method shows that the laser induces a resonant coupling between the excited state and the ground state, i.e., a light-induced conical intersection. The theory accounts for the timing and direction of the effect.
Pinacol closure of oxygenated taxane skeleta at C-1-C-2 with stereoinduction by oxygen substituents at C-9 and C-10

Abstract The treatment of keto aldehydes 4 and 5 with low-valent Ti results in stereoselective intramolecular pinacol couplings that lead to optically active oxygenated taxane skeleta 2 and 3.
Development of a spined underwater biomimetic vehicle with SMA actuators

We present here our progress towards the development of a type of biomimetic active hydrofoil that utilizes Shape Memory Alloy (SMA) actuator technology. The actuation is presently applied to the control of hydrodynamic forces and moments, including thrust generation, on a 2D hydrofoil. The SMA actuation elements are two sets of thin wires (0.015' to 0.027') on either side of an elastomer element that provides the main structural support. Controlled heating and cooling of the two wire sets generates bi-directional bending of the elastomer, which in turn deflects (for quasi-static control) or oscillates (for thrust generation) the trailing edge of the hydrofoil. The aquatic environment of the hydrofoil lends itself to cooling schemes that utilize the excellent heat transfer properties of water. The SMA actuator was able to deflect the trailing edge by +/- 5 degree(s) at rates as high as 2 Hz. FEM modeling of hydrofoil response to thermoelectric heating has been carried out using a thermomechanical constitutive model for SMAs. FEM predictions are compared with experimental measurements.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Lexical analysis and parsing techniques for a vector machine

The use of vector oriented hardware for compilation places a special burden on the compiler writer to make use of vector operations whenever possible. This paper presents various techniques for lexical analysis and parsing using the CDC STAR-100 instruction set. Although the similarity between APL and the STAR is apparent, previous techniques developed by Lincoln and others using APL as a base cannot be used directly on the STAR. Difficulties involved in implementing such methods occur because of the non-uniform treatment of vectors of different types on the STAR as opposed to a very uniform treatment in APL. The relevant features of the STAR-100 are discussed after which techniques are described for performing lexical analysis of a source text. The goal is to reduce the text to a set of tokens of unit length. Finally some parsing methods are suggested.
Prediction of periodic loadings on single rotation propfan with off-axis inflow

A three-dimensional Green's function potential paneling method is used to predict the propfan unsteady load in a yawed flow condition when the axis of blade rotation is inclined to the freest ream. Unsteady response is predicted in a frequency domain with proper predetermined interblade phase angle. The method is shown to be accurate and efficient in computation comparing to a time-domain calculation. Single-rotation propfan blade SR2 is used to demonstrate the capability. The effects of shaft angle of attack, advance ratio, number of blades, and Mach number on the response due to the off-axis inflow are studied. The results indicate that the shaft angle of attack has a major effect on the unsteady blade loading.
Living with the "enemy": An analysis of foreign investment in the Japanese equity market

Abstract This paper studies the impact of foreign investment on domestic financial markets. In particular, it examines the empirical validity of some protectionist claims used by regulators to restrict foreign investment. These people argue that: (1) trading by foreign investors tends to increase market volatility more than trading by domestic investors; (2) foreign investors have more sophisticated investment technology than do their domestic counterparts, causing domestic investors to “lose out” to foreign ones; and (3) foreign investors tend to make investment decisions on the basis of short-term gains rather than long-term fundamentals, such as corporate dividend growth. We find no evidence supporting these claims from the Japanese experience. To the contrary, we find that foreign investors tend to be long-term contrarian players in the market.
Big Cohen-Macaulay algebras and seeds

In this article, we delve into the properties possessed by algebras, which we have termed seeds, that map to big Cohen-Macaulay algebras. We will show that over a complete local domain of positive characteristic any two big Cohen-Macaulay algebras map to a common big Cohen-Macaulay algebra. We will also strengthen Hochster and Huneke's ``weakly functorial" existence result for big Cohen-Macaulay algebras by showing that the seed property is stable under base change between complete local domains of positive characteristic. We also show that every seed over a positive characteristic ring maps to a balanced big Cohen-Macaulay -algebra that is an absolutely integrally closed, -adically separated, quasilocal domain.
3,4-Diazabenzvalene, the azoalkane precursor to tetrahedrane. Synthesis and reactivity.

Abstract The title diazene 1 has been synthesized and shown to decompose thermally to cyclobutadiene over a surprisingly small barrier.
Spitzer Observations of the Dusty Warped Disk of Centaurus A

Spitzer mid-infrared images of the dusty warped disk in the galaxy Centaurus A show a parallelogram-shaped structure. We successfully model the observed mid-infrared morphology by integrating the light from an emitting, thin, and warped disk, similar to that inferred from previous kinematic studies. The models with the best match to the morphology lack dust emission within the inner 0.1-0.8 kpc, suggesting that energetic processes near the nucleus have disturbed the inner molecular disk, creating a gap in the molecular gas distribution.
Impacts of Central America gap winds on the SST annual cycle in the eastern Pacific warm pool

The annual cycle of sea surface temperature (SST) in the eastern Pacific warm pool and its relation to Central America gap winds are examined in this study. Locally enhanced annual harmonics of SST are found underneath the regions where the Tehuantepec and Papagayo gap winds blow. The SSTs underneath the Tehuantepec gap wind undergo larger annual variations than those underneath the Papagayo gap wind. This suggests that the Tehuantepec gap wind has a stronger influence on the annual cycle of SST than the Papagayo gap wind. A series of ocean model experiments are performed to demonstrate the enhancement effect of the gap winds. Further heat budget analyses of the experiments show that the gap winds increase the amplitude of the SST annual cycle primarily by enhancing the vertical entrainment process in the ocean. The thermal forcing effect of the gap winds is less important in modulating the SST annual cycle.
Improving the Vitamin K Status of Breastfeeding Infants With Maternal Vitamin K Supplements

Objective. To increase the phylloquinone (vitamin K1) concentration of human milk with maternal oral phylloquinone supplements such that both the phylloquinone intake of breastfed infants and their serum concentrations of phylloquinone would approach those of formula-fed infants who are known to be at much less risk for hemorrhagic disease of the newborn. Design. Two stages: stage I, longitudinal, randomized study of 6 weeks9 duration; and stage II, longitudinal, randomized, double-blind, placebo-controlled study of 12 weeks9 duration. Setting. Patients from a private pediatric practice in Madison, WI. Patients. Stage I: sequential sampling of 20 lactating mothers to determine the level of maternal supplementation needed in stage II. Ten mothers received 2.5 mg/d oral phylloquinone, and 10 mothers received 5.0 mg/d oral phylloquinone. Stage II: sequential sampling of 22 human milk-fed infants and lactating mothers. All infants received 1 mg of phylloquinone at birth. Eleven mothers received a placebo; 11 mothers received 5 mg/d phylloquinone. Measurements and Results. In stage I, both 2.5 and 5.0 mg/d phylloquinone significantly increased the phylloquinone content of human milk at both 2 and 6 weeks. As expected, 5.0 mg had a greater effect (mean ± SD, 58.96 ± 25.39 vs 27.12 ± 12.18 ng/mL at 2 weeks). In stage II, the vitamin K-supplemented group had significantly higher maternal serum phylloquinone concentrations, higher phylloquinone milk concentrations, and higher infant plasma phylloquinone concentrations at 2, 6, and 12 weeks compared with the placebo group. At 12 weeks infant phylloquinone intakes were significantly higher for the vitamin K group than the placebo group (9.37 ± 4.55 vs 0.15 ± 0.07 μg/kg per day). This corresponded to a plasma phylloquinone concentration in the vitamin K group of 2.84 ± 3.09 vs 0.34 ± 0.57 ng/mL in the placebo group. At 12 weeks, the prothrombin times did not differ between the groups, but the des-γ-carboxy-prothrombin (partially carboxylated prothrombin thought to be a measure of vitamin K deficiency) was significantly elevated in the placebo group compared with the vitamin K group (1.48 ± 1.19 vs 0.42 ± 0.55 ng/mL). Conclusion. In exclusively breastfed infants who receive intramuscular phylloquinone at birth, the vitamin K status as measured by plasma phylloquinone and des-γ-carboxy-prothrombin concentrations is improved by maternal oral supplements of 5 mg/d phylloquinone through the first 12 weeks of life.
Return electron transfer in radical ion pairs of triplet multiplicity

Return electron transfer (RET) in radical ion pairs may populate the reagent ground states or, in the case of triplet pairs, one reagent triplet state. The efficiency of triplet RET is governed by the free energies of singlet and triplet RET and by the topologies of the poten- tial surfaces of parent molecules, radical ions, and accessible triplet states or biradicals. RET in triplet radical ion pairs is exemplified for two distinct relationships between the three po- tential surfaces.
Multifunctionality and Agricultural Trade Negotiations

Differing views of multifunctionality—attributing nonmarket benefits to agricultural production—continue to be an obstacle in World Trade Organization (WTO) negotiations. Some nations see multifunctionality as justifying subsidies to agricultural production; others see it as disguised protection. This paper shows that while multifunctionality never justifies trade interventions, it can justify production subsidies or taxes. Recognizing that the subsidies or taxes can be economically efficient policies, nations must precisely define and value the externalities in order to design policies and defend those interventions in the WTO. Trade rules are developed that accommodate domestic policy intervention while preventing disguised protection.
Laser spectroscopy of CoH: Spin-orbit splitting of the ground state

Abstract Six new bands in the visible spectrum of gas-phase CoH have been identified via laser excitation spectroscopy. Three of these bands, at 5710, 6093, and 6215 A, have been rotationally analyzed and are found to originate from the Ω ″ = 4 component of the X3Φi ground state. Resolved fluorescence patterns from the Ω ′ = 3 upper state of the weak, ΔΩ ≠ 0 6215- A band enabled us to measure the spin-orbit splitting between the Ω ″ = 4 and 3 components of the ground state as −728 (±3) cm−1. This measurement confirms the assignment of the ground state as 3Φi and links all the known states of CoH. The upper states display many strong perturbations characteristic of open d-shell, transition metal diatomics.
A FURTHER DROP INTO QUIESCENCE BY THE ECLIPSING NEUTRON STAR 4U 2129+47

The low-mass X-ray binary 4U 2129+47 was discovered during a previous X-ray outburst phase and was classified as an accretion disk corona source. A 1% delay between two mid-eclipse epochs measured ~22 days apart was reported from two XMM-Newton observations taken in 2005, providing support to the previous suggestion that 4U 2129+47 might be in a hierarchical triple system. In this work, we present timing and spectral analysis of three recent XMM-Newton observations of 4U 2129+47, carried out between 2007 November and 2008 January. We found that except for the two 2005 XMM-Newton observations, all other observations are consistent with a linear ephemeris with a constant period of 18 857.63 s; however, we confirm the time delay reported for the two 2005 XMM-Newton observations. Compared to a Chandra observation taken in 2000, these new observations also confirm the disappearance of the sinusoidal modulation of the light curve as reported from two 2005 XMM-Newton observations. We further show that, compared to the Chandra observation, all of the XMM-Newton observations have 40% lower 0.5-2 keV absorbed fluxes, and the most recent XMM-Newton observations have a combined 2-6 keV flux that is nearly 80% lower. Taken as a whole, the timing results support the hypothesis that the system is in a hierarchical triple system (with a third body period of at least 175 days). The spectral results raise the question of whether the drop in soft X-ray flux is solely attributable to the loss of the hard X-ray tail (which might be related to the loss of sinusoidal orbital modulation), or is indicative of further cooling of the quiescent neutron star after cessation of residual, low-level accretion.
Changes of short latency somatosensory evoked potential in sleep

We studied how the first negative waves (frontal 'N18' and parietal 'N20') of median somatosensory evoked potentials (SEP) change from waking to sleep in 9 healthy volunteers. Frontal and parietal responses in awake subjects showed multiple fast frequency potentials (FFP) over the ascending and descending phases of the slow negative waves. The main frontal FFP consisted of N16, P17, N18, P18, N19 and P20, with an additional small FFP, n15, over the ascending phase of N16. The parietal FFP included 3 major peaks (N15, P18 and N20) and 3 small FFP (n17, n19 and n20). Frontal FFP, except for n15, were markedly attenuated or totally disappeared in stage II sleep. Only a few FFP were identified in stage IV. The FFP returned in REM sleep, but amplitude was smaller than the waking state. Parietal FFP were also attenuated in NREM and recovered in REM sleep, but these changes were less prominent compared to those of frontal FFP. Latencies of frontal P20 and parietal N20 were prolonged in NREM sleep with greater prolongation of P20 than N20. These returned to waking values in REM sleep. These findings suggest that the frontal and parietal major negative peaks ('N18' and 'N20') consist of multiple physioanatomical substrates mediated through complex thalamocortical projection systems, and that the FFP are closely related to the sleep-wake mechanism possibly reflected by mutual interaction between cortex and the thalamic reticular system.
Enantioselective Aldehyde α-Nitroalkylation via Oxidative Organocatalysis

The first enantioselective organocatalytic α-nitroalkylation of aldehydes has been accomplished. The aforementioned process involves the oxidative coupling of an enamine intermediate, generated transiently via condensation of an amine catalyst with an aldehyde, with a silyl nitronate to produce a β-nitroaldehyde. Two methods, one that furnishes the syn β-nitroaldehyde and a second that provides access to the anti isomer, have been developed. Data are presented to support a hypothesis that explains this phenomenon in terms of a silyl group-controlled change in mechanism. Finally, a three-step procedure for the synthesis of both syn- and anti-α,β-disubstituted β-amino acids is presented.
Time-variant structured matrices: an application to instrumental variable methods

ABSTRACT We derive a recursive algorithm for the time—update of the triangular factors of non-Hermitian time-variant matrices with structure. These are matrices that undergo low-rankmodifications as time progresses, special cases of which often arise in adaptive filtering andinstrumental variable (IV) methods. A natural implementation of the algorithm is via twocoupled triangular arrays of processing elements. We consider, in particular, an IV parameterestimation problem and show how the arrays collapse to a coupled parallelizable solution ofthe identification problem. 1. INTRODUCTION The notion of displacement structure provides a natural framework for the solution of manyproblems in signal processing and mathematics. It represents a powerful and unifying toolfor exploiting structure in numerous applications, as detailed in several recent surveys on thetopic.1'2'3 More recently, we have extended the concept of structured matrices to the time-variant setting4'5'6 and shown that we can, as well, study matrices that undergo low-rankmodifications as time progresses. Special examples often arise in adaptive filtering.7'8'9 Inthis paper, we further extend our earlier results to the non-Hermitian case and exhibit anapplication to instrumental variable
Enhancing phonon transmission across a Si/Ge interface by atomic roughness: First-principles study with the Green's function method

Knowledge on phonon transmittance as a function of phonon frequency and incidence angle at interfaces is vital for multiscale modeling of heat transport in nanostructured materials. Although thermal conductivity reduction in nanostructured materials can usually be described by phonon scattering due to interface roughness, we show how a Green's function method in conjunction with the Landauer formalism suggests that interface roughness induced by atomic mixing can increase phonon transmission and interfacial thermal conductance. This is an attempt to incorporate first-principles force constants derived from ab initio density-functional theory (DFT) into Green's function calculation for infinitely large three-dimensional crystal structure. We also demonstrate the importance of accurate force constants by comparing the phonon transmission and thermal conductance using force constants obtained from semiempirical Stillinger-Weber potential and first-principles DFT calculations.
On semifree symplectic circle actions with isolated fixed points

Abstract Let M be a symplectic manifold, equipped with a semi-free symplectic circle action with a finite, non-empty fixed point set. We show that the circle action must be Hamiltonian, and M must have the equivariant cohomology and Chern classes of (P1)n.
Facile Synthesis of Highly Functionalized Ethyltrifluoroborates

Organotrifluoroborates are generating increased interest because of their ease of preparation and purification and indefinite shelf life. Herein we report the preparation of organotrifluoroborates bearing functional groups that can be manipulated at different stages of the synthetic route, exploiting the inertness of their carbon−boron bonds. The alkylation of 2,2-dicyanoethyltrifluoroborate with a variety of electrophiles and of (EWG)2CH2 with potassium iodomethyltrifluoroborate resulted in di- and trisubstituted ethyltrifluoroborates in good to excellent yields.
SPECTRAL METHODS FOR TIME-DEPENDENT STUDIES OF ACCRETION FLOWS. III. THREE-DIMENSIONAL, SELF-GRAVITATING, MAGNETOHYDRODYNAMIC DISKS

Accretion disks are three-dimensional, turbulent, often self-gravitating, magnetohydrodynamic (MHD) flows, which can be modeled with numerical simulations. In this paper, we present a new algorithm that is based on a spectral decomposition method to simulate such flows. Because of the high order of the method, we can solve the induction equation in terms of the magnetic vector potential and, therefore, ensure trivially that the magnetic fields in the numerical solution are divergence free. The spectral method also suffers minimally from numerical dissipation and allows for an easy implementation of models for subgrid physics. Both properties make our method ideal for studying MHD turbulent flows such as those found in accretion disks around compact objects. We verify our algorithm with a series of standard tests and use it to show the development of MHD turbulence in a simulation of an accretion disk. Finally, we study the evolution and saturation of the power spectrum of MHD turbulence driven by the magnetorotational instability.
On the separability of assembly preferences

Analyses of assembly elections often assume that voters have well-defined preferences over candidates, even though preferences over assemblies are the natural analytic starting point. This candidate-based approach is usually justified by an assumption that preferences over assemblies are separable. We show, however, that if preferences over assemblies are themselves derived from underlying preferences over legislative or economic outcomes, then preferences over assemblies will not in general be separable.
Synthesis, structure, and bonding of the nonclassical Zintl phase K5As3Pb3.

The title phase was synthesized by direct fusion of a stoichiometric amount of the elements followed by annealing at 650 °C for 3 weeks. The compound crystallizes in the orthorhombic space group Pnma (No. 62), Z = 4, with a = 19.451(6) A, b = 12.164(3) A, c = 6.581(1) A. The compound is made up of As3Pb35- crown clusters that can be likened geometrically and electronically to 6-atom hypho-clusters derived from a tricapped trigonal prismatic closo parent. These crowns are interconnected via intercluster Pb−Pb bonds to form infinite chains along the b axis, which means the compound contains an extra two cations and two electrons per formula unit. Extended Huckel calculations indicate that the two additional electrons per cluster are accommodated in π* states on the cluster and predict that the phase should be semiconducting. The latter is confirmed by microwave resistivity measurements, ρ298 = 1.0 × 102 μΩ·cm; (δρ/δT)/ρ = −0.14(3) K-1.
Temperature Distribution Study in a Cooled Radial Inflow Turbine Rotor

A numerical study to determine the temperature distribution in the rotor of a radial inflow turbine is presented. The study is based on the use of the finite element method in the three dimensional heat conduction problem. Different cooling techniques with various coolant to primary mass flow ratios are investigated. The resulting temperature distribution in the rotor are presented for comparison.
A rhodium catalyst for single-step styrene production from benzene and ethylene

Rising global demand for fossil resources has prompted a renewed interest in catalyst technologies that increase the efficiency of conversion of hydrocarbons from petroleum and natural gas to higher-value materials. Styrene is currently produced from benzene and ethylene through the intermediacy of ethylbenzene, which must be dehydrogenated in a separate step. The direct oxidative conversion of benzene and ethylene to styrene could provide a more efficient route, but achieving high selectivity and yield for this reaction has been challenging. Here, we report that the Rh catalyst ( Fl DAB)Rh(TFA)(η 2 –C 2 H 4 ) [ Fl DAB is N,N ′-bis(pentafluorophenyl)-2,3-dimethyl-1,4-diaza-1,3-butadiene; TFA is trifluoroacetate] converts benzene, ethylene, and Cu(II) acetate to styrene, Cu(I) acetate, and acetic acid with 100% selectivity and yields ≥95%. Turnover numbers >800 have been demonstrated, with catalyst stability up to 96 hours.
Glassy behavior of electrons as a precursor to the localization transition

Abstract A theoretical model is presented, describing the glassy freezing of electrons in the vicinity of disorder-driven metal–insulator transitions. Our results indicate that the onset of glassy dynamics should emerge before the localization transition is reached, thus predicting the existence of an intermediate metallic glass phase between the normal metal and the insulator.
A search for narrow band 21-cm wavelength signals from ten nearby stars

Abstract A search for narrow band radio signals, in the 21-cm wavelength band, possibly generated by other civilizations, has been made in the direction of ten stars. No such signals were found and upper limits to the power of possible transmissions toward the Earth are given.
Strings, branes and two-time physics

Abstract We generalize the ideas and formalism of two-time physics from particle dynamics to some specific examples of string and p -brane ( p ≥1) dynamics. The two-time string or p -brane action can be gauge fixed to produce various one-time string or p -brane actions that are dual to each other under gauge transformations. We discuss the particular gauges that correspond to tensionless strings and p -branes in flat ( d −1)+1 spacetime, rigid strings and p -branes in flat ( d −1)+1 spacetime, and tensionless strings and p -branes propagating in the AdS d − n ×S n backgrounds.
Automated thermal and reliability analysis of avionics designs

This paper describes a new automated process currently being developed and implemented at General Dynamics Convair/Space Systems Divisions to enhance the reliability of printed circuit boards (PCB's). The process is entitled Convair-Computer Aided Reliable Design (C-CARD) and is used to optimize the component mounting locations on a PCB for thermal reliability. PCB information contained in a computer-aided design (CAD) database is used to automatically produce a thermal mathematical model for use with the SINDA finitedifference heat-transfer code. Resulting temperature and reliability predictions are displayed and evaluated by the packaging engineer based on the design requirements. A plot of isotherms on the PCB surface is also determined from the analysis. If necessary, the components are relocated and this procedure is repeated. The isotherm data are used to guide any needed relocation. Once the PCB design is optimized for thermal reliability, it is then released for manufacture. In this way, the heat-transfer analysis is integrated into the design process and provides the packaging engineer with a thermally safe design in minutes instead of weeks.
Safe Contexts for Interorganizational Collaborations Among Homeland Security Professionals

In many domains of increased turbulence and volatility, interorganizational ad hoc collaborations are common. One such domain is homeland security in which security professionals collaborate virtually with individuals outside of their own organizations in response to a security threat. In such a domain, a safe context is needed to ensure that interactions with collaborators not only help to solve the immediate threat but also avoid the improper use by outside parties of information released during these collaborations. We use the heuristic systematic model of information processing to hypothesize that the relationship between different safe context factors and a security professional's perceptions of collaboration success will be contingent on differences in geographic proximity of the collaborating parties-differences in proximity that are not related to differences in physical face-to-face contact but to differences in social proximity. Our exploratory empirical investigation finds support for the hypothesized interaction effect: safe contexts that require deeper processing are related to higher levels of perceived success when the parties are geographically proximal (with no differences in face-to-face contact), whereas safe contexts that involve heuristic-based processing are related to success when parties are geographically less proximal. Our findings suggest that the utility of safe context factors is contextualized based on the proximity of interacting parties, that geographical proximity's social space dimension plays a key role independent of differences in physical face-to-face contact, and that, practically, to be successful, ad hoc collaborators should have access to a range of safe context factors, using them in different combinations depending on the proximity of network members.