cssi/SciSciGPT-SciSciNet huggingface dataset:
Improved cardiac motion self-gating

Background Cardiac motion self-gating is a technique where MRI signal is used to derive motion triggers instead of ECG, which might be problematic in high B0 field or cases where ECG is not accessible (e.g. fetal cardiac imaging). However, the performance of existing cardiac self-gating approaches have not yet enabled clinical utility. We propose and evaluate here a novel cardiac self-gating strategy that potentially improves the trigger detection accuracy and reliability.
Optimum design of a composite structure with manufacturing constraints

Abstract Composite designs produced by multidisciplinary optimization computer programs are often expensive or impossible to produce. In this paper, constraints needed in the optimization process to reduce manufacturing cost or reduce the need for post-optimization design changes are presented. The interactions of the manufacturing constraints with other constraints and the design variable scheme are investigated. Additionally, a design case study is performed, comparing wings designed with a conventional method and the method described in this paper. The designs were built and tested to verify modelling assumptions and the effectiveness of the manufacturing constraints.
Packing of α-helices: Geometrical constraints and contact areas☆

Abstract The helical packing in sperm whale myoglobin has been examined. Using cylindrical co-ordinates based on each helix axis in turn, the overlap of the side-chain atoms of a helix with the surrounding atoms from other parts of the structure was 2.3 A, but the distribution was not at all uniform and severe overlap occurred in at least one location for each helix. Simple axial translations or rotations of any helix in the native structure are not permitted motions. Translation perpendicular to the helix axis in at least one direction is not restricted by interlocking side-chains. The approach of two helices along the contact normal connecting their axes produces solvent exclusion effects at a distance of about 6 A from the final position. The solvent-excluded area found in such interaction sites is equivalent to a large hydrophobic contribution to the free energy of association. The six principal sites correspond by themselves to 40% of the total area change in going from the extended sausage model to the native structure. The mean atom-packing densities for these sites and the standard deviations of these values are similar and are equal to that found for the protein as a whole. Helices of close-packed spheres form useful approximations to actual peptide helices. The helix of index number four corresponds closely to an α-helix. The required sphere size corresponds in volume to residues such as leucine or methionine. The predicted packing scheme for such helices corresponds to the three general classes of interactions actually seen. Making use of the geometry implied by the close-packed sphere helix, an algorithm is proposed for picking potentially strong helix-helix interaction sites in peptide chains of known sequence. When combined with preliminary secondary structure predictions, it is suggested that this algorithm might usefully restrict the search for these specific types of contact in the docking portion of a general folding program.
Roles of His-Rich Hpn and Hpn-Like Proteins in Helicobacter pylori Nickel Physiology

Individual gene-targeted hpn and hpn-like mutants and a mutant with mutations in both hpn genes were more sensitive to nickel, cobalt, and cadmium toxicity than was the parent strain, with the hpn-like strain showing the most metal sensitivity of the two individual His-rich protein mutants. The mutant strains contained up to eightfold more urease activity than the parent under nickel-deficient conditions, and the parent strain was able to achieve mutant strain activity levels by nickel supplementation. The mutants contained 3- to 4-fold more and the double mutant about 10-fold more Ni associated with their total urease pools, even though all of the strains expressed similar levels of total urease protein. Hydrogenase activities in the mutants were like those in the parent strain; thus, hydrogenase is fully activated under nickel-deficient conditions. The histidine-rich proteins appear to compete with the Ni-dependent urease maturation machinery under low-nickel conditions. Upon lowering the pH of the growth medium from 7.3 to 5, the wild-type urease activity increased threefold, but the activity in the three mutant strains was relatively unaffected. This pH effect was attributed to a nickel storage role for the His-rich proteins. Under low-nickel conditions, the addition of a nickel chelator did not significantly affect the urease activity of the wild type but decreased the activity of all of the mutants, supporting a role for the His-rich proteins as Ni reservoirs. These nickel reservoirs significantly impact the active urease activities achieved. The His-rich proteins play dual roles, as Ni storage and as metal detoxification proteins, depending on the exogenous nickel levels.
Distribution and origin of corticotropin-releasing factor-immunoreactive axons in the female rat lumbosacral spinal cord.

Corticotropin-releasing factor (CRF) is a neuropeptide traditionally known for its hormonal role in the hypothalamic/pituitary/adrenal stress axis. However, CRF has been reported in axons in sites that may be considered outside of the direct stress axis, e.g., in axons in the lumbosacral spinal cord associated with the micturition response. Whether any of these CRF-immunoreactive axons interacts with uterine-related preganglionic autonomic neurons or projection neurons in the lumbosacral spinal cord is unknown. Thus, immunohistochemistry and retrograde tracing were employed to determine the presence, distribution, and origin of CRF-immunoreactive axons in the L6/S1 spinal cord of the female rat and to ascertain whether these axons are associated with uterine-related neurons. CRF-immunoreactive axons were present in the dorsal horn, medial and lateral collateral pathways, dorsal intermediate gray, laminae VlI and X, and sacral parasympathetic nucleus of the spinal cord. Nitric oxide-synthesizing, i.e., NADPH-d-positive neurons and pseudorabies virus labeled uterine-related neurons were in the sacral parasympathetic nucleus and were closely apposed by CRF-immunoreactive axons. Injection of retrograde tracers (fluorogold or fast blue) into the L6/S1 spinal cord labeled neurons in the hypothalamic paraventricular nucleus and pontine Barrington's nucleus, and some of these neurons were immunoreactive for CRF. This study demonstrates that CRF-immunoreactive axons are present in the L6/S1 spinal cord of the female rat in areas associated with sensory and autonomic processing. Some of these axons originate from the paraventricular nucleus and Barrington's nucleus and are adjacent to uterine-related neurons. These results indicate that CRF may influence neural activity related to the female reproductive system. J Neurosci. Res. 66:1217–1225, 2001. © 2001 Wiley-Liss, Inc.
Ultra-sensitive magnetic field sensor based on a low-noise magnetoelectric MEMS-CMOS oscillator

This paper reports on the first demonstration of a high performance magnetic field sensor (sub-10 nT/Hz 1/2 resolution) based on a high frequency (168.2 MHz), compact and low-power consumption (~3 mW), self-sustained magnetoelectric MEMS-CMOS oscillator. For the first time, a high electromechanical performance (quality factor Q = 1101 and electromechanical coupling coefficient k t 2 = 1.16%) AlN/FeGaB nano-plate (250 nm / 250 nm) resonator working at a higher order lateral-extensional mode of vibration was connected to a CMOS chip-based self-sustaining oscillator loop for direct frequency read-out. Because of the large value of the resonator figure of merit (FOM = k t 2 ·Q~13), direct wire-bonding of the magnetoelectric MEMS resonator to a Pierce oscillator taped out in the ON Semiconductor 0.5-μm CMOS process was made possible. This first prototype was characterized for DC magnetic field from -200 Oe to 200 Oe, showing high sensitivity (221.4 Hz/μT) and low detection limit (9.3 nT/Hz 1/2 ) when the magnetic field was applied along the length of the resonator, representing the first demonstration of a high resolution MEMS magnetoelectric resonant sensor interfaced to a compact and low power, self-sustained oscillator as direct frequency readout.
Excess of the PBO over the ABO and hard pension freezes

This paper examines the role of the excess of the projected benefit obligation (PBO) over the accumulated benefit obligation (ABO) in hard pension freezes. Using a sample of 109 firms that announced hard freezes during the period 2003–2008, I find that firms with a larger excess of the PBO over the ABO are more likely to hard freeze their pension plans. Furthermore, I document an average abnormal return of more than 1.2 % on the announcement day for the freeze firms. More importantly, the cumulative abnormal returns around pension freeze announcements are positively associated with the excess of the PBO over the ABO, and this positive association is more pronounced for firms with a higher level of institutional ownership, suggesting that institutional investors are more likely to understand the impact of hard pension freezes on firm value by incorporating pension information disclosed in the footnotes. Overall, this study provides evidence that firms shift away from defined benefit plans through pension freezes, and also highlights the importance of considering the excess of the PBO over the ABO in research on hard pension freezes.
Biosynthesis of glycerolipids by heptoma and liver microsomes. I. Fatty acyl-CoA ligase and acyl-CoA:sn-glycerol-3-phosphate acyltransferase

Abstract The intracellular membranes of hepatomas exhibit an altered content and composition of lipid compared to the membranes of normal liver. In order to elucidate the role of lipid biosynthetic enzymes in these membrane differences, we first examined the fatty acyl-CoA ligase and acyl-CoA: sn-glycerol3-phosphate (Gro-3P) acyltransferase activities and acyl specificities of microsomes from liver, Morris hepatoma 7288C, and hepatoma tissue culture (HTC) cells. Based upon incorporation of fatty acid and Gro-3P, it is concluded that acyl-CoA: sn-Gro-3P acyltransferase activities are markedly elevated (6–30-fold) in the microsomes of Morris Hepatoma 7288C and HTC cells compared to microsomes from liver, whereas the fatty acyl-CoA ligase activity is reduced (30–50-fold). Therefore, the low phospholipid content of these tumor cells does not appear to result from reduced acyltransferase activity. Though diminished ligase activity may play a role, it appears that activation of fatty acid may not be rate-limiting, even at the low levels of fatty acyl-CoA ligase present in the tumor and HTC cells. Preliminary evidence suggests that another factor that may be responsible for the low tumor phospholipid content is the limited availability of Gro-3P, a lipid precursor. The phospholipid in hepatoma 7288C is also characterized by an elevated ratio of monenoic to dienoic fatty acid. We have found that this change does not reflect an altered specificity of acyl-CoA: sn-Gro-3P acyltransferase.
Polarographic maxima of the first kind: characteristics in absence of resistance-controlled currents

Abstract Characteristics of polarographic maxima, studied by means of three-electrode circuitry, are described. There are major differences as compared with results obtained with two-electrode circuits; the literature on this subject has hitherto been restricted to studies in the latter category.
Unveiling functional protein motions with picosecond x-ray crystallography and molecular dynamics simulations

A joint analysis of all-atom molecular dynamics (MD) calculations and picosecond time-resolved x-ray structures was performed to gain single-molecule insights into mechanisms of protein function. Ensemble-averaged MD simulations of the L29F mutant of myoglobin after ligand dissociation reproduce the direction, amplitude, and time scales of crystallographically determined structural changes. This close agreement with experiments at comparable resolution in space and time validates the individual MD trajectories. From 1,700 single-molecule trajectories, we identified and structurally characterized a conformational switch that directs dissociated ligands to one of two nearby protein cavities. Subsequent ligand migration proceeds through a network of transiently interconnected internal cavities, with passage between them involving correlated protein–ligand motions. The simulations also suggest how picosecond protein motions modulate the functional dissociation of oxygen and suppress the geminate recombination of toxic carbon monoxide.
Fragrance material review on ionone

A toxicologic and dermatologic review of ionone when used as a fragrance ingredient is presented.
Evolution Dynamics of Pore Sizes, Cell Volume, Ionic Concentrations Following High-Voltage Pulsing

Model studies are presented for nanopore dynamics of cells subjected to high-intensity voltage pulsing. The role of concentration differences leading to osmotic flows, cell-size modulation, and resulting stresses on the plasma membrane are all comprehensively probed. Our results show that the life span of pores can either be short or very long depending on various conditions. Our model results are consistent with recent experimental observations and suggest that nanopores with a larger radius would tend to evolve into long-lived metastable entities. This has obvious implications to both drug delivery and gene transfer.
The relationship between importance of retail store attributes and lifestyle of mature female consumers

Mature female consumers are an affluent market segment often ignored by retailers. This study examines the relationship between importance of selected store attributes (such as location and price) and lifestyle characteristics. The results indicate that certain lifestyle characteristics are related to the importance placed on store attributes.
Geochemistry of lead contaminated wetland soils amended with phosphorus

To remediate Pb contaminated soils it is proposed that phosphorus can be amended to the soils to transform the Pb into poorly soluble Pb-phosphate mineral phases. However, remediation strategies must account for variable Pb speciation and site-specific factors. In this study soil mineralogy and Pb speciation in soils from P-amended field trials at sites within the Coeur d’Alene River Basin in Idaho, USA were investigated. The soils are contaminated from mining activities and are enriched with Fe and Mn. Selective extraction of the soils indicated that the Fe oxides are poorly crystalline. XRD of the soil clay size fractions identified quartz, muscovite, kaolinite, siderite, lepidocrocite, and chlorite minerals. Amendment with P fertilizer dissolved the siderite. No Pb–phosphate minerals were detected by XRD. Electron microprobe analysis showed direct correlations between Pb, Fe, and Mn in the unamended soils, and negative correlations between Pb and Si. Lead and Mn were strongly correlated. In the amended soils Fe and P were strongly correlated. Results indicate that the Pb is associated with poorly crystalline Fe and Mn oxides, and that added P is primarily associated with Fe oxide phases. Comparisons of pore water Pb concentrations with chloropyromorphite and plumbogummite solubility suggest that in the phosphate-amended soils the pore waters are undersaturated in these phases, whereas several of the control soil pore waters were oversaturated, indicating the added phosphate suppressed the Pb solubility. Results from this research provide insight into the geochemistry occurring in the P-remediated soils that will help in making management and remediation decisions.
Minor loading vein acclimation for three Arabidopsis thaliana ecotypes in response to growth under different temperature and light regimes.

In light of the important role of foliar phloem as the nexus between energy acquisition through photosynthesis and distribution of the products of photosynthesis to the rest of the plant, as well as communication between the whole plant and its leaves, we examined whether foliar minor loading veins in three Arabidopsis thaliana ecotypes undergo acclimation to the growth environment. As a winter annual exhibiting higher rates of photosynthesis in response to cooler versus warmer temperatures, this species might be expected to adjust the structure of its phloem to accommodate greater fluxes of sugars in response to growth at low temperature. Minor (fourth- and third-order) veins had 14 or fewer sieve elements and phloem tissue comprised 50% or more of the cross-sectional area. The number of phloem cells per minor loading vein was greater in leaves grown under cool temperature and high light versus warm temperature and moderate light. This effect was greatest in an ecotype from Sweden, in which growth under cool temperature and high light resulted in minor veins with an even greater emphasis on phloem (50% more phloem cells with more than 100% greater cross-sectional area of phloem) compared to growth under warm temperature and moderate light. Likewise, the number of sieve elements per minor vein increased linearly with growth temperature under moderate light, almost doubling over a 27°C temperature range (21°C leaf temperature range) in the Swedish ecotype. Increased emphasis on cells involved in sugar loading and transport may be critical for maintaining sugar export from leaves of an overwintering annual such as A. thaliana, and particularly for the ecotype from the northern-most population experiencing the lowest temperatures.
Frequent red cell transfusions reduced vascular endothelial activation and thrombogenicity in children with sickle cell anemia and high stroke risk.

Stroke is one of the most disabling complications of sickle cell anemia (SCA). The molecular mechanisms leading to stroke in SCA or by which packed red blood cell (PRBC) transfusion prevents strokes are not understood. We investigated the effects of PRBC transfusion on serum biomarkers in children with SCA who were at high-risk for stroke. Serum samples from 80 subjects were analyzed, including baseline, study exit time point and 1 year after study exit. Forty of the 80 samples were from subjects randomized to standard care and 40 from transfusion arm. Samples were assayed for levels of BDNF, sVCAM-1, sICAM-1, MPO, Cathepsin-D, PDGF-AA, PDGF-AB/BB, RANTES (CCL5), tPAI-1, and NCAM-1 using antibody immobilized bead assay. Significantly lower mean serum levels of sVCAM-1 (2.2 × 106 ± 0.8 × 106 pg/mL vs. 3.1 × 106 ± 0.9 × 106 pg/mL, P < 0.0001), Cathepsin-D (0.5 × 106 ± 0.1 × 106 pg/mL vs. 0.7 × 106 ± 0.2 × 106 pg/mL, P < 0.0001), PDGF-AA (10556 ± 4033 pg/mL vs. 14173 ± 4631 pg/mL, P = 0.0008), RANTES (0.1 × 106 ± 0.07 × 106 pg/mL vs. 0.2 × 106 ± 0.06 × 106 pg/mL, P < 0.006), and NCAM-1 (0.7 × 106 ± 0.2 × 106 pg/mL vs. 0.8 × 106 ± 0.1 × 106 pg/mL, P < 0.0006) were observed among participants who received PRBC transfusion, compared to those who received standard care. Twenty or more PRBC transfusion over 4 years was associated with lower serum levels of sVCAM-1 (P < 0.001), PDGF-AA (P = 0.025), and RANTES (P = 0.048). Low baseline level of BDNF (P = 0.025), sVCAM-1 (P = 0.025), PDGF-AA (P = 0.01), t-PAI-1 (P = 0.025) and sICAM-1 (P = 0.022) was associated with higher probability of stroke free survival. Beyond improving hemoglobin levels, our results suggest that the protective effects of PRBC transfusion on reducing stroke in SCD may result from reduced thrombogenesis and vascular remodeling. Am. J. Hematol. 89:47–51, 2014. © 2013 Wiley Periodicals, Inc.
Stern-Gerlach Dynamics with Quantum Propagators

We study the quantum dynamics of a nonrelativistic neutral particle with spin in inhomogeneous external magnetic fields. We first consider fields with one-dimensional inhomogeneities, both unphysical and physical, and construct the corresponding analytic propagators. We then consider fields with two-dimensional inhomogeneities and develop an appropriate numerical propagation method. We propagate initial states exhibiting different degrees of space localization and various initial spin configurations, including both pure and mixed spin states. We study the evolution of their spin densities and identify characteristic features of spin density dynamics, such as the spatial separation of spin components, and spin localization or accumulation. We compare our approach and our results with the coverage of the Stern-Gerlach effect in the literature, and we focus on nonstandard Stern-Gerlach outcomes, such as radial separation, spin focusing, spin oscillation, and spin flipping.
Subgroups and conjugates in semi-prime rings

In this paper we obtain results on normal subgroups in semi prime rings which enable us to extend results in [3] on the solvability of normal subgroups and results in [4] on conjugates of noncentral elements. The main tool in our investigation is the recent work of Herstein [2] on the Lie structure of semi prime rings. To use these results we must make an assumption which guarantees a rich supply of elements of square zero, and so, a rich supply of units. Some such assumption is necessary as illustrated by our example in [-4] which shows that even in a prime ring with zero divisors the group of units can be abelian and can centralize noncentral elements, even in the presence of an infinite collection of independent elements of square zero.
Synthetic Aperture Sonar Imaging of Simple Finite Targets

During the Sediment Acoustics Experiment 2004 (SAX04), a synthetic aperture sonar (SAS) was used to detect simple targets that were either proud or buried below a water-sediment interface, where the nominal grazing angle of incidence from the SAS to the point above a buried target was well below the critical grazing angle. SAS images from other measurements below the critical angle have also produced target detections of buried spheres and finite cylinders. Models and numerical simulations are developed to investigate these proud and buried target detections. For buried targets, the simulations include estimates of reverberation from the rough seafloor, the subcritical penetration through the seafloor, scattering from a target, and propagation back to the SAS. For proud targets, the simulations include the scattering from the target where interaction with the seafloor is included through simple ray models. The simulations used environmental and material parameters measured during SAX04. The environmental measurements include profiles of small-scale surface roughness and superimposed ripple structure. The SAS simulations and model/measurement comparisons over a frequency range of 10-50 kHz further support scattering from sediment ripple structure as the dominant mechanism for subcritical penetration in this range.
Distribution of antarctic zooplankton around Elephant Island during the austral summers of 1988, 1989, and 1990

Year to year variation and vertical distributions of epipelagic Zooplankton around Elephant Island and King George Island were examined with samples collected with bongo nets and a 1 m2 MOCNESS during the austral summers (Jan–Feb.) of 1988, 1989 and 1990. Copepods were the major components of epipelagic Zooplankton (in numbers) with dominance of Metridia gerlachei (1988 and 1989) and small calanoids and cyclopoids (1990). Euphausiids and salps were the next most abundant groups. The percent composition of euphausiids decreased from 1988 to 1990 while that of salps increased. The abundance of salps exceeded euphausiids and major taxa of copepods in 1990. Local patches of polychaetes and amphipods were also found. Statistically significant annual variations with increased numbers in 1990 were found by analyses of variance in total abundance, abundances of copepods, salps, chaetognaths and amphipods, but abundances of euphausiids, polychaetes and fishes showed no significant annual variations. When the study area was divided geographically, horizontal variability in abundance within each year showed no significance in total abundance, abundances of copepods, euphausiids, amphipods and fishes, but significance in salps, polychaetes and chaetognaths. Results of site clustering based on covariances of abundances of eleven major taxa were well matched, though not perfect, with the distribution of surface water temperatures which could be used as a tracer of source water masses suggesting that spatial variation was related to hydrodynamic conditions. Factor analyses showed that annual and spatial variations in abundance were mainly caused by only two taxa, Metridia gerlachei and salps (mostly Salpa thompsoni). These two taxa were responsible for about 60% and 30% of total variance, respectively, and were useful indicators of the interannual variation. That is, 1988 and 1989 were the years of M. gerlachei, and 1990 was the year of salps. From vertically stratified MOCNESS samples, it was shown that the major taxa in this study area were active vertical migrators. While most samples obtained by relatively shallow tows (uppermost 100 m depth) were composed of exclusively one or two taxa, those from relatively deep tows (down to 200 m) showed various patterns of vertical stratification suggesting that the patterns of vertical migration were species specific. Species specific ontogenetic vertical migration associated with elevated habitat temperatures also seemed to be responsible for the annual variation in zooplankton distribution in the upper water column.
Automatic identification of embedded network rows in large-scale optimization models

The solution of a large-scale linear, integer, or mixed integer programming problem is often facilitated by the exploitation of special structure in the model. This paper presents heuristic algorithms for identifying embedded network rows within the coefficient matrix of such models. The problem of identifying a maximum-size embedded pure network is shown to be among the class of NP-hard problems. The polynomially-bounded, efficient algorithms presented here do not guarantee network sets of maximum size. However, upper bounds on the size of the maximum network set are developed and used to show that our algorithms identify embedded networks of close to maximum size. Computational tests with large-scale, real-world models are presented.
Hedonic Estimation of Quality Factors Affecting the Farm-Retail Margin

A model of the farm-retail marketing margin is tested using producer and retail prices of a perishable product in which time during season and quality characteristics are variable. Empirical analysis verifies that the marketing margin of California fresh peaches decreases during the season and increases with improved quality. Results identify potential producer gains from improving product quality early in the season, and from price signals compensating producers for quality characteristics other than weight.
Ponderomotive pseudopotential near gyroresonance

The enhancement of the ponderomotive potential near gyroresonance is investigated both experimentally and theoretically. Because of nonadiabaticity near gyroresonance the potential is finite and depends on the transit time of the particle through the rf field structure.
Inhibitory effect of pyridoxine deficiency on growth of a transplanted tumor in rats.

SummaryTwo experiments were conducted using rats of the Marshall 520 strain depleted in vit. B6 by the use of a deficient diet and 4-desoxypyridoxine. Osteogenic Sarcoma 344 was transplanted into the deficient animals, a pair-fed group and an ad libitum group. Desoxypyridoxine was removed from the diet of the deficient animals on the day of tumor transplant. In Exp. 1 daily measurements of the tumor showed a marked inhibition of the growth of the tumor in the deficient animals as compared to the control groups. The mean weight of the tumor and also the mean weight as a percentage of final mean total body weight were also decreased. In a second experiment larger, more mature animals were used. Tumor inhibition in the deficient animals was again observed, although it was not so striking as in the first experiment. No histological differences in the tumor were noted in either experiment with the exception of increased hemorrhage and necrosis in the neoplasms of the ad libitum animals.
On the robustness of the modified beta distribution for acceptance sampling in statistical quality control

The purpose of this article is to examine the robustness of the modified Beta distribution as a probability distribution of lot fraction defectives in Bayesian acceptance sampling for statistical quality control. In complex manufacturing systems, a production process may consist of multiple production stages in a serial or nonserial fashion. Hence, inputs to a production station can be a result of subassembly of several inputs, or outputs of some inspection stations for some prior work stages. We investigate the effectiveness of the modified Beta distribution as an approximation to the lot fraction defectives probability of inputs at intermediate work stations. The robustness of the modified Beta distribution simplifies both the determination of the optimal sampling plan for acceptance sampling, and the calibration of distributions resulted from subassembly or inspection operations in complex manufacturing systems.
Reactions of pyrrole with Ni(100)

The reactions of pyrrole with a clean Ni(100) surface have been studied with temperature programmed reaction (TPR), reflection absorption infrared spectroscopy (RAIS), and Auger electron spectroscopy (AES). RAIS indicated that pyrrole adsorbs on clean Ni(100) at 200 K with its ring parallel to the surface, presumably via π -bonding with the 1A 2 orbital. During TPR experiments with a heating rate of 8 K/s, pyrrole desorbs molecularly at 235 K and dihydrogen evolves above room temperature, in accord with equilibrium thermodynamics. During TPR experiments with a heating rate of 45 K/s, new pathways emerge. Light gases, principally HCN, H 2 , and NH 3 , desorb at circa 570 K. The variation of pyrrole decomposition products with slightly different heating rates suggests a change from a decomposition reaction to a polymerization reaction with increasing heating rates.
Replica-scaling analysis of a directed manifold in a random medium, and ground-state properties of attractive and repulsive Bose systems.

A replica theory for the scaling properties of directed manifolds of internal dimension D immersed in a random (D+d)-dimensional medium and the related theory for Bose systems with pairwise interaction are presented. For zero temperature and disorder decreasing with distance, the wandering exponent is given by the Nattermann formula [J. Phys. C 18, 6661 (1985)] \ensuremath{\zeta}=(4-D)/4 (which implies that the correlation-length exponent of the percolation problem in the 1+\ensuremath{\epsilon} approximation is given by ${\ensuremath{\nu}}^{\mathrm{\ensuremath{-}}1}$=\ensuremath{\epsilon}/2). For nonzero temperature \ensuremath{\zeta}=(2-D)/2 for 0D2d/(2+d), and \ensuremath{\zeta}=2/(2+d) for Dg2d/(2+d). The ground-state energy of a d-dimensional attractive Bose system with hard-core interaction and particle number n\ensuremath{\gg}1 scales for d2 as ${\mathit{E}}_{\mathit{n}}$\ensuremath{\simeq}-${\mathit{n}}^{(4\mathrm{\ensuremath{-}}\mathit{d})/(2\mathrm{\ensuremath{-}}\mathit{d})}$${\mathit{c}}^{2/(2\mathrm{\ensuremath{-}}\mathit{d})}$ when (nc${)}^{1/(\mathit{d}\mathrm{\ensuremath{-}}2)}$\ensuremath{\ge}a, and ${\mathit{E}}_{\mathit{n}}$\ensuremath{\simeq}-${\mathit{cn}}^{2}$/${\mathit{a}}^{\mathit{d}}$ when (nc${)}^{1/(\mathit{d}\mathrm{\ensuremath{-}}2)}$\ensuremath{\le}a, where c is the attraction strength and a is the core radius. For dg2 a bound state arises when (nc${)}^{1/(\mathit{d}\mathrm{\ensuremath{-}}2)}$\ensuremath{\ge}a and the corresponding ground-state energy scales as ${\mathit{E}}_{\mathit{n}}$\ensuremath{\simeq}-${\mathit{cn}}^{2}$/${\mathit{a}}^{\mathit{d}}$. For the case of repulsive interactions, a connection is made to other treatments of the problem.
The effects of a computer malfunction on subsequent task performance

Although previous research has examined the effects of computer malfunctions on employee frustration, to our knowledge no research has explored computer malfunction's effect on subsequent task perf...
The Equivalent Circuit of a Corner Bend in a Rectangular Wave Guide

Following the fundamentals set down in an earlier paper, the impedance representation of a right-angle bend in a rectangular wave guide is calculated. Two types of bends are considered, being defined by the polarization of the electric field relative to the plane of the bend. The results are stated in the form of infinite series. Numerical results are given
Obtaining information through the atmosphere at the diffraction limit of a large aperture

An analysis is made which shows that if the pupil plane of a large telescope is relayed into a special achromatic prism interferometer of 180° rotational shear and with point symmetry, the second statistical moment of the pupil irradiance fluctuations reveals information about the source two-dimensional mutual coherence function (MCF) at spatial frequencies that, under ordinary conditions, are severely attenuated by propagation through the atmosphere. To obtain a measure of the MCF at points across the telescope pupil simultaneously, it is necessary to use a two-dimensional photo-electronic array detector, with real-time processing.
The impact of international and industrial diversification strategies on the cash flow sensitivity of cash

Purpose – The purpose of this paper is to examine the impact of the two diversification strategies on firms' propensity to save cash out of cash flow.Design/methodology/approach – The author examines the quarterly data of Compustat's active and research firms from the first quarter of 1999 to the last quarter of 2005, with a sample size of more than 79,000 firm quarters. A two‐step GMM Instrumental Variable regression of change in cash holdings, on variables that measure the degree of industrial as well as international diversification strategies, is employed to investigate whether each diversification strategy alleviates or exacerbates firm's propensity to save cash out of its cash flows.Findings – Evidence is found that industrial diversification mitigates the propensity of firms to save cash out of their cash flows. When the sample is partitioned into financially constrained and financially non‐constrained firms, industrial diversification reduces propensity of firms to save cash out of cash flows for ...
Approximate weighted matching on emerging manycore and multithreaded architectures

Graph matching is a prototypical combinatorial problem with many applications in high-performance scientific computing. Optimal algorithms for computing matchings are challenging to parallelize. Approximation algorithms are amenable to parallelization and are therefore important to compute matchings for large-scale problems. Approximation algorithms also generate nearly optimal solutions that are sufficient for many applications. In this paper we present multithreaded algorithms for computing half-approximate weighted matching on state-of-the-art multicore (Intel Nehalem and AMD Magny-Cours), manycore (Nvidia Tesla and Nvidia Fermi), and massively multithreaded (Cray XMT) platforms. We provide two implementations: the first uses shared work queues and is suited for all platforms; and the second implementation, based on dataflow principles, exploits special features available on the Cray XMT. Using a carefully chosen dataset that exhibits characteristics from a wide range of applications, we show scalable performance across different platforms. In particular, for one instance of the input, an R-MAT graph (RMAT-G), we show speedups of about 32 on 48 cores of an AMD Magny-Cours, 7 on 8 cores of Intel Nehalem, 3 on Nvidia Tesla and 10 on Nvidia Fermi relative to one core of Intel Nehalem, and 60 on 128 processors of Cray XMT. We demonstrate strong as well as weak scaling for graphs with up to a billion edges using up to 12,800 threads. We avoid excessive fine-tuning for each platform and retain the basic structure of the algorithm uniformly across platforms. An exception is the dataflow algorithm designed specifically for the Cray XMT. To the best of the authors' knowledge, this is the first such large-scale study of the half-approximate weighted matching problem on multithreaded platforms. Driven by the critical enabling role of combinatorial algorithms such as matching in scientific computing and the emergence of informatics applications, there is a growing demand to support irregular computations on current and future computing platforms. In this context, we evaluate the capability of emerging multithreaded platforms to tolerate latency induced by irregular memory access patterns, and to support fine-grained parallelism via light-weight synchronization mechanisms. By contrasting the architectural features of these platforms against the Cray XMT, which is specifically designed to support irregular memory-intensive applications, we delineate the impact of these choices on performance.
Indirect Effects in Path Analysis

The indirect effect in path analysis has been defined as equal to the difference between the correlation coefficient and the path coefficient. This definition has led to ambiguous and inconsistent ...
A novel information fusion methodology for intelligent terrain analysis

This paper presents a novel information fusion methodology for intelligent terrain analysis. In our application, we define information as terrain characteristics derived from sensor data extracted from on-board spacecraft sensors. The fuzzy-logic construct allows one to represent the terrain characteristics using an easily understandable, linguistic approach. Once derived, these fuzzy terrain characteristics are blended together using a fuzzy rule base to produce a coherent representation of terrain safety. The fused information is then used to autonomously select a safe landing site for spacecraft touchdown. The fuzzy terrain analysis and fusion methodology is explained in detail. Computer simulation results are provided to show the viability of the approach.
The Comparative Statics of Collective Action: A Pragmatic Approach to Games with Multiple Equilibria

The prevailing approaches to collective action in the rational choice paradigm often lead to implausible conclusions and tend to lack predictive power. This article introduces a method to overcome these difficulties. The method is based on the notion of stability sets of pure-strategy equilibria, already familiar from the literature on equilibrium selection and with close counterparts in evolutionary game theory. With the help of some simple examples, the article shows how this method can turn many intuitive insights into operational, testable hypotheses about phenomena of collective action.
Analysis of phenanthrene diol epoxide mercapturic acid detoxification products in human urine: relevance to molecular epidemiology studies of glutathione S-transferase polymorphisms

Many studies have investigated the effects of glutathione S-transferase (GST) polymorphisms on cancer incidence in people exposed to carcinogenic polycyclic aromatic hydrocarbons (PAHs). The basis for this is that the carcinogenic bay region diol epoxide metabolites of several PAH are detoxified by GSTs in in vitro studies. However, there are no reports in the literature on the identification in urine of the mercapturic acid metabolites that would result from this process in humans. We addressed this by developing a method for quantitation in human urine of mercapturic acids which would be formed from angular ring diol epoxides of phenanthrene (Phe), the simplest PAH with a bay region, and a common environmental pollutant. We prepared standard mercapturic acids by reactions of syn- or anti-Phe-1,2-diol-3,4-epoxide and syn- or anti-Phe-3,4-diol-1,2-epoxide with N-acetylcysteine. Analysis of human urine conclusively demonstrated that the only detectable mercapturic acid of this type—N-acetyl-S-(r-4,t-2,3-trihydroxy-1,2,3,4-tetrahydro-c/t-1-phenanthryl)-L-cysteine (anti-PheDE-1-NAC)—was derived from the ‘reverse diol epoxide’, anti-Phe-3,4-diol-1,2-epoxide, and not from the bay region diol epoxides, syn- or anti-Phe-1,2-diol-3,4-epoxide. Levels of anti-PheDE-1-NAC in the urine of 36 smokers were (mean ± SD) 728 ± 859 fmol/ml urine. The results of this study provide the first evidence for a mercapturic acid of a PAH diol epoxide in human urine, but it was not derived from a bay region diol epoxide as molecular epidemiologic studies have presumed, but rather from a reverse diol epoxide, representative of metabolites with little if any carcinogenic activity. These results demonstrate the need for integration of genotyping and phenotyping information in molecular epidemiology studies.
Impact sensitivity and crystal lattice compressibility/free space

There is considerable evidence, which we discuss, indicating that compressibility and available free space in the crystal lattice are among the factors that govern the sensitivity of an explosive compound. Expanding and extending earlier work, we demonstrate, for 25 explosives, that there is an overall general tendency for greater impact sensitivity as the estimated free space per molecule increases. More specific relationships can be discerned by looking at subgroups of the compounds. The nitramine sensitivities, most of which are quite high, increase nearly linearly but only very gradually with free space. The nitroaromatics cover a wide range of sensitivities but all have an approximately similar intermediate level of free space. The remaining types of compounds show a reasonable sensitivity–free space relationship with one outlier: FOX-7 (1,1-diamino-2,2-dinitroethylene).
Efficient Intramolecular Hydroalkoxylation of Unactivated Alkenols Mediated by Recyclable Lanthanide Triflate Ionic Liquids: Scope and Mechanism

Lanthanide triflate complexes of the type [Ln(OTf)(3)] (Ln=La, Sm, Nd, Yb, Lu) serve as effective, recyclable catalysts for the rapid intramolecular hydroalkoxylation (HO)/cyclization of primary/secondary and aliphatic/aromatic hydroxyalkenes in imidazolium-based room-temperature ionic liquids (RTILs) to yield the corresponding furan, pyran, spirobicyclic furan, spirobicyclic furan/pyran, benzofuran, and isochroman derivatives. Products are straightforwardly isolated from the catalytic solution, conversions exhibit Markovnikov regioselectivity, and turnover frequencies are as high as 47 h(-1) at 120 degrees C. The ring-size rate dependence of the primary alkenol cyclizations is 5>6, consistent with a sterically controlled transition state. The hydroalkoxylation/cyclization rates of terminal alkenols are slightly more rapid than those of internal alkenols, which suggests modest steric demands in the cyclic transition state. Cyclization rates of aryl-functionalized hydroxyalkenes are more rapid than those of the linear alkenols, whereas five- and five/six-membered spirobicyclic skeletons are also regioselectively closed. In cyclization of primary, sterically encumbered alkenols, turnover-frequency dependence on metal-ionic radius decreases by approximately 80-fold on going from La(3+) (1.160 A) to Lu(3+) (0.977 A), presumably reflecting steric impediments along the reaction coordinate. The overall rate law for alkenol hydroalkoxylation/cyclization is v approximately k[catalyst](1)[alkenol](1). An observed ROH/ROD kinetic isotope effect of 2.48 (9) is suggestive of a catalytic pathway that involves kinetically significant intramolecular proton transfer. The present activation parameters--enthalpy (DeltaH(++))=18.2 (9) kcal mol(-1), entropy (DeltaS(++))=-17.0 (1.4) eu, and energy (E(a))=18.2 (8) kcal mol(-1)--suggest a highly organized transition state. Proton scavenging and coordinative probing results suggest that the lanthanide triflates are not simply precursors of free triflic acid. Based on the kinetic and mechanistic evidence, the proposed catalytic pathway invokes hydroxyl and olefin activation by the electron-deficient Ln(3+) center, and intramolecular H(+) transfer, followed by alkoxide nucleophilic attack with ring closure.
Age-dependent differences in reorganization of primary somatosensory cortex following low thoracic (T12) spinal cord transection in cats

The organization of primary somatosensory cortex was examined in chronic spinal cats that had sustained cord transection at T12 at 3 ages: 2 and 6 weeks of age, and as adults. Five months to 1 yr following transection, the deprived cortex was mapped electrophysiologically (multiunit recordings). The topographical organization found at each age was compared to that present in normal adults to study effects of developmental age on the ability of the somatosensory system to adjust to changes in afferent input. Cortical responses to deprivation of somatosensory input were age dependent. In animals cord transected at 2 weeks of age, the remaining somatic afferent input excited both its normal cortical area and the area normally reserved for the hindlimb. This resulted in 2 somatotopic maps of the rostral trunk and forelimb. In contrast, in cats spinalized at 6 weeks of age, there was only 1 map for the remaining somatosensory input that was distributed across the mediolateral axis of the primary somatosensory cortex. As a result, the remaining somatosensory input was shifted medially from its normal position and was narrower with respect to the rostrocaudal area driven by light tactile input. The amount of cortex that each body region could excite was essentially the same as in normal animals. In adults, a third response was observed; regions normally devoted to forelimb and trunk appeared to be unchanged, and the region previously serving the hindlimb responded only to a limited extent, and only to tactile stimulation of the trunk. In all cases, however, some sites in the cortex could be excited by parts of the body that in normal animals were served by cortical regions from 3 to 10 mm away, a distance much in excess of the maximum extent of reported thalamocortical overlap. We suggest that the various patterns of cortical organization observed at different ages reflect different developmental processes that are active at the time of transection. Further, we hypothesize that often, in major denervations such as spinal cord transection, a significant component of the reorganization occurs at synaptic levels below the cortex in young animals.
BANK FAILURE AND CONTAGION EFFECTS: EVIDENCE FROM HONG KONG

In this paper the influence of three Hong Kong bank failures on stock prices of the colony's banking industry is examined. As deposit insurance is nonexistent in Hong Kong, the world's fourth-largest financial center, an interesting environment is provided for testing contagion effects of bank failure on other healthy financial institutions. By examining contagion effects in an environment void of explicit deposit insurance, this study should provide interesting insights into the resiliency of modern-day financial markets. In turn, insights should also be provided into debates concerning the role and reform of deposit insurance and the rationale for regulation of the financial services industry in general. The results indicate that unexpected bank failure causes significant negative stock price reactions within the banking industry; yet, some banks are less affected than others.