cssi/SciSciGPT-SciSciNet huggingface dataset:
The relation of cortisol reactivity and anxiety to perinatal outcome in primiparous adolescents

The relation of cortisol reactivity and self-report anxiety to perinatal outcomes was examined in a sample of 38 primiparous adolescents. Maternal cortisol and anxiety levels obtained in the first half of pregnancy and in mid-third trimester were found to be related to the gestational age of newborns, with higher levels of cortisol and/or anxiety predicting greater chance of pre- or postmature birth. However, when measured over time, a greater increase in cortisol levels was more predictive of positive perinatal outcomes, such as no meconium in labor. These findings suggest that certain levels of maternal reactivity/anxiety are necessary for positive perinatal outcomes.
Striatal volume on magnetic resonance imaging and repetitive behaviors in autism.

Background The repetitive behaviors seen in autism phenotypically resemble those seen in obsessive-compulsive disorder (OCD) and Tourette Syndrome (TS), disorders in which structural and functional abnormalities of the basal ganglia (BG) are present and correspond to the severity of repetitive behaviors. Methods Seventeen subjects with autism by DSM-IV and Autism Diagnostic Interview (ADI) and 17 matched controls completed a 1.5 T magnetic resonance image (MRI) of the brain. Two blinded researchers, with good inter-rater reliability, outlined the right and left caudate and putamen. Autistic and control BG volumes covaried for total brain volume were compared using analysis of covariance. BG volumes within the autistic group were correlated with the ADI Repetitive Behavior scores (ADI-C domain). Results Right caudate volume controlled for total brain volume was significantly larger in autistic subjects than in controls. In addition, right caudate and total putamen volumes correlated positively with repetitive behavior scores on the ADI-C domain, particularly the higher order OCD-like repetitive behaviors. Conclusions Increased right caudate volume in autism is of interest, since this has also been observed in OCD patients. Increased volume of the right caudate and total putamen positively correlated with greater repetitive behaviors, supporting the hypothesis of BG dysfunction associated with repetitive behaviors in autistic adults.
Image Motion and Resolution For Air-To-Air Photography

The resolution and blur due to image motion for air-to-air photography are discussed. Analyses involving range, relative velocities, miss distances, focal lengths, exposure times, angular rates and lens-film resolution capabilities are presented, Equations are derived for resolution and image blur due to linear and/or angular motions. Curves and nomograms are presented which permit determination of the parameters.
Detecting and tracking humans using a man-portable robot

Large gains in the automation of human detection and tracking techniques have been made over the past several years. Several of these techniques have been implemented on larger robotic platforms, in order to increase the situational awareness provided by the platform. Further integration onto a smaller robotic platform that already has obstacle detection and avoidance capabilities would allow these algorithms to be utilized in scenarios that are not plausible for larger platforms, such as entering a building and surveying a room for human occupation with limited operator intervention. However, transitioning these algorithms to a man-portable robot imparts several unique constraints, including limited power availability, size and weight restrictions, and limited processor ability. Many imaging sensors, processing hardware, and algorithms fail to adequately address one or more of these constraints. In this paper, we describe the design of a payload suitable for our chosen man-portable robot, the iRobot Packbot. While the described payload was built for a Packbot, it was carefully designed in order to be platform agnostic, so that it can be used on any man-portable robot. Implementations of several existing motion and face detection algorithms that have been chosen for testing on this payload are also discussed in some detail.
The effectiveness of methenamine as a urinary antiseptic at various hydrogen-ion concentrations

Summary At a P H of 6.0, urine with a 0.5 per cent concentration of methenamine rarely sterilizes itself at the end of twenty-four hours. At a P H of 5.0 urine with a 0.5 per cent concentration of methenamine can be sterile after four hours at 37°C. Treatment with methenamine, without constant control of the P H of the urine, is likely to be unsuccessful.
On the information complexity of cascaded norms with small domains

We consider the problem of estimating cascaded norms in a data stream, a well-studied generalization of the classical norm estimation problem, where the data is aggregated in a cascaded fashion along multiple attributes. We show that when the number of attributes for each item is at most d, then estimating the cascaded norm L k ○L 1 requires space Ω(d·n1–2/k) for every d = O(n1/k). This result interpolates between the tight lower bounds known previously for the two extremes of d = 1 and d = Θ(n1/k) [1]. The proof of this result uses the information complexity paradigm that has proved successful in obtaining tight lower bounds for several well-known problems. We use the above data stream problem as a motivation to sketch some of the key ideas of this paradigm. In particular, we give a unified and a more general view of the key negative-type inequalities satisfied by the transcript distributions of communication protocols.
Neural steroid hormone receptor gene expression in pregnant rats.

Abstract Estrogen and progesterone play important roles during pregnancy in stimulating the onset of maternal behavior at parturition. The status of receptor expression of these hormones during pregnancy in neural regions that regulate maternal behavior is unclear. The objective of the present study is to characterize changes in neural gene expression of the estrogen receptors α and β (ERα and ERβ) and the progesterone receptor (PR) during the latter part of pregnancy. Brains from primigravid Sprague–Dawley rats were collected on days 15 and 21 of pregnancy. Micropunches of the olfactory bulb (OB), medial preoptic area (MPOA), bed nucleus of the stria terminalis (BnST), hypothalamus (HYP), medial amygdala (MeA), and the temporal cortex (TCx) were analyzed by real-time RT-PCR (Taqman™) for levels of gene expression. No changes in either ERα or ERβ mRNA levels were detected in any brain region between days 15 and 21 of pregnancy: however, the MPOA had higher levels of both ERα and ERβ than other brain regions. Progesterone receptor mRNA levels, in contrast, declined significantly in the MPOA, HYP, and TCx, between days 15 and 21 of pregnancy (P
In vitro response of human fibroblasts to commercially pure titanium.

The generation of metal particles through surface wear of prosthetic joints has been associated with biological reactions that may lead to prosthetic component loosening. The role of the macrophage in these reactions has been studied extensively, but that of the fibroblast has not. The few fibroblast studies that there have been have shown that particles of several metals, with sizes over a wide range, can promote cytokine release and may cause cell necrosis. The intent of this study was to determine if there are metal particle exposure threshold levels that result in morphological changes and cell necrosis of fibroblasts in peri-articular tissues. Retrieved human fibroblasts (superior medial plica) were cultured in standard fashion and then were exposed to various particle dosages of commercially pure Titanium (cpTi). Cell morphological changes and necrosis were observed to occur when the total mass of the particle dosage exceeded a threshold level. These data imply that these cell responses occur at threshold levels of wear particle exposure.
Student survey report: Washington dentists questioned on expanded duties.

Opinions of Washington state dentists on the use of expanded duties for dental auxiliaries were surveyed in a questionnaire mailed six months after the state’s dental law was amended. Fifty-five percent of the dentist population responded. The percentage of positive responses to the use of expanded duties for dental assistants and hygienists decreased with the increasing age of dentists surveyed. Results of the survey indicate that opinions of the dentists were not related to the size of the community in which they practice. Dentists who were least busy most strongly favored expanded duties for both auxiliaries.
Asymptotics for Christoffel Functions with Varying Weights

We prove sharp asymptotics for Christoffel functions @l"n(w^2^n,.) with respect to varying weights w^2^n. The result has an interpretation in the theory of statistical-mechanical models of quantum systems, and it is sufficiently strong to yield asymptotics for Christoffel functions for weights defined on several intervals.
In situ nanoscale wet imaging of the heterogeneous catalyzationof nitriles in a solution phase: novel hydrogenation chemistry through nanocatalysts on nanosupports

Wet-environmental transmission electron microscopy studies of heterogeneous hydrogenation of complex nitriles in a liquid phase over new mesoporous cobalt-promoted ruthenium nanocatalysts on reducible nanotitania supports are presented. The desorbed organic products in the dynamic liquid phase hydrogenation are imaged situ on the nanoscale. The direct studies on the “nanocomposite” catalysts are correlated with parallel reaction chemistry measurements. They demonstrate high hydrogenation activity at low operating temperatures in the presence of atomic scale anion vacancy defects associated with Lewis acid sites at the nanosupport surface and an electronic and synergistic contribution to the promoter mechanism. The combined synergistic effect between the two metals and the interaction with the reduced nanosupport leading to an electronic modification lead to highly reactive site for the hydrogenation catalysis. The results illustrate novel selective hydrogenation chemistry with mesoporous nanocatalyst systems on nanosupports.
One- to Two-Electron Reduction of an [FeFe]-Hydrogenase Active Site Mimic: The Critical Role of Fluxionality of the [2Fe2S] Core

The one- to two-electron reduction of μ-(1,2-ethanedithiolato)diironhexacarbonyl that has been observed under electrochemical conditions is dependent on scan rate and temperature, suggesting activation of a structural rearrangement. This structural rearrangement is attributed to fluxionality of the [2Fe2S] core in the initially formed anion. Computations support this assessment. Upon an initial one-electron reduction, the inherent fluxionality of the [2Fe2S] complex anion allows for a second one-electron reduction at a less negative potential to form a dianionic species. The structure of this dianion is characterized by a rotated iron center, a bridging carbonyl ligand, and, most significantly, a dissociated Fe−S bond. This fluxionality of the [2Fe2S] core upon reduction has direct implications for the chemistry of [FeFe]-hydrogenase mimics and for iron−sulfur cluster chemistry in general.
An Ab Initio Nuclear Magnetic Resonance and Atoms-in-Molecules Study of the PO Bond in Phosphine Oxides

Ab initio nuclear magnetic resonance (NMR) calculations on the effect of correlation on phosphorus shielding in the phosphine oxides clearly suggest the absence of conventional multiple bonding in the PO bond. Atoms-in-molecules (AIM) studies that yield AIM-based localized molecular orbitals indicate one highly polarized σ bond plus strong back-bonding of the oxygen π orbitals, a picture consistent with a number of prior investigations. While it has been argued that the strong character of the PO bond in the phosphine oxides is highlighted best by the R3PO formula, the present study indicates that the situation is better pictured as R3P+−O-.
Conductance of single cobalt chalcogenide cluster junctions.

Understanding the electrical properties of semiconducting quantumdot devices have been limiteddue tothevariabilityoftheirsize/compositionandthechemistry of ligand/electrode binding. Furthermore, to probe their electrical conduction properties and its dependence on ligand/electrode binding, measurements must be carried outatthesingledot/clusterlevel.Hereinwereportscanning tunneling microscope based break junction measurements of cobalt chalcogenide clusters with Te, Se and S to probe the conductance properties. Our measured conductance trendsshowthattheCoTebasedclustershavethehighest conductance while the Co-S clusters the lowest. These trends are in very good agreement with cyclic voltammetry measurements of the first oxidation potentials and with density functional theory calculations of their HOMO� LUMO gaps.
The Role of Fiscal Transparency in Sustaining Stability and Growth in Latin America

Latin America has experienced a resurgence in growth in recent years. However, it is also a region that has been prone to crises while growth has not delivered a significant reduction in poverty and inequality. Maintaining a strong and stable macroeconomic performance in Latin America will depend on further cuts in public debt, identification and reduction of fiscal vulnerabilities and improvements in the quality of public spending. Improvements in governance and the business environment will also aid in attracting investment. This paper draws on assessments of fiscal transparency in twelve countries in Latin America to highlight good fiscal management and improvements in fiscal transparency that might enhance the prospect for sound fiscal performance and a more favorable investment environment. This would be an important step toward sustaining stable, higher quality growth in the region.
Shock-wave-enhancement of the mixing and the stability limits of supersonic hydrogen-air jet flames

A supersonic, non-premixed, jetlike flame was stabilized along the axis of a Mach-2.5 wind tunnel, and wedges were mounted on the sidewall in order to interact oblique shock waves with the flame. Schlieren photographs show how the interaction occurs, and measurements quantify how the flame length and the flame blowout limits are affected by the shocks. An optimum shock-interaction location was investigated by adjusting the wedge position. It was found that shock waves enhance the fuel-air mixing such that flame lengths decreased by 20% when an optimum shock location and shock strength were chosen. Enhanced mixing resulted, in part, because the shocks turn the flow and induce radial inflows of air into the fuel jet. A Mach disk sometimes occurs, which appears to split the reaction zone into two parts and severely distorts the flame shape. Substantial improvements in the flame stability (i.e., changes in the blowout limits) were achieved by properly interacting the shock waves with the flame-holding recirculation zone. The reason for the significant improvement in flame stability is believed to be the adverse pressure gradient caused by the shock, which can elongate the recirculation zone. Excessive shock strength (or poor shock placement) caused thermal choking to occur, and the flame base moved upstream of the fuel tube exit, leading to dangerously high wall heat transfer rates. Optimization of the mixing and stability limits requires a careful matching of the shock-flame interaction location and the shock strength. The experimental results show that the best mixing and stability correspond to 10° wedges placed at an upstream position (4 d F ) such that the primary shocks create radial inflow near the flame base and interact with the recirculation zone. This upstream wedge position also allowed the second (recompression) set of shocks to provide radial inflow near the flame tip.
Standards of Scientific Conduct: Are There Any?

The practice of research is full of ethical challenges, many of which might be addressed through the teaching of responsible conduct of research (RCR). Although such training is increasingly required, there is no clear consensus about either the goals or content of an RCR curriculum. The present study was designed to assess community standards in three domains of research practice: authorship, collaboration, and data management. A survey, developed through advice from content matter experts, focus groups, and interviews, was distributed in November 2010 to U.S. faculty from 50 graduate programs for each of four different disciplines: microbiology, neuroscience, nursing, and psychology. The survey addressed practices and perceived standards, as well as perceptions about teaching and learning. Over 1,300 responses (response rate of 21 %) yielded statistically significant differences in responses to nearly all questions. However the magnitude of these differences was typically small, leaving little reason to argue for community consensus on standards. For nearly all questions asked, the clear finding was that there was nothing approaching consensus. These results may be useful not so much to teach what the standards are, but to increase student awareness of the diversity of those standards in reported practice.
ErbB receptor tyrosine kinase network inhibition radiosensitizes carcinoma cells.

Purpose The expression of epidermal growth factor receptor (EGFR)-CD533, a truncation mutant of the wild-type EGFR, radiosensitizes carcinoma and malignant glioma cell lines. This deletion mutant disrupts EGFR activation and downstream signaling through the formation of inhibitory dimerizations. In this study, the effects of EGFR-CD533 on other ErbB receptor tyrosine kinase (RTK) family members were quantified to better understand the mechanism of EGFR-CD533–mediated radiosensitization. Methods and Materials Breast carcinoma cell lines with different ErbB RTK expression profiles were transduced with EGFR or ErbB2 deletion mutants (EGFR-CD533 and ErbB2-CD572) using an adenoviral vector. ErbB RTK activation, mitogen activated protein kinase (MAPK) and phosphatidylinositol-3-kinase (PI3K)/p70S6K signaling, and clonogenic survival were determined for expression of each deletion mutant. Results EGFR-CD533 radiosensitizes carcinoma cells with either high EGFR expression (MDA-MB231) or low EGFR expression (T47D) through significant blockade of the ErbB RTK network. Analysis of clonogenic survival demonstrate significant enhancement of the α/β ratios, as determined by the linear-quadratic model. Split-dose survival experiments confirm that EGFR-CD533 reduces the repair of cellular damage after ionizing radiation. Conclusion Expression of EGFR-CD533 inhibits the ErbB RTK network and radiosensitizes carcinoma cells irrespective of the ErbB RTK expression patterns, and ErbB2-CD572 does not radiosensitize cells with low EGFR expression. These studies demonstrate that the mechanism of action for EGFR-CD533–mediated radiosensitization is inhibition of the ErbB RTK network, and is an advantage for radiosensitizing multiple malignant cell types.
Urinary excretion of mutagens in cirrhosis: Limited evidence of an association

Although bacterial mutagenesis assays have detected mutagenic substances in urine from smokers and patients treated with certain medications, these assays have not found mutagens in body fluids of subjects without such exposures. A recent report, however, suggested that mutagenic substances were present in the urine of unexposed individuals with cirrhosis. Since this observation could have important implications for the metabolism of potentially toxic substances and might provide leads to the cause of the high incidence of hepatoma among patients with cirrhosis, the reproduction of those findings of that report was attempted. In contrast with the earlier report, no evidence of mutagenic substances in urine samples from unexposed patients with cirrhosis was observed. While differences between these studies might be attributed to the subjects tested, it seems possible that the mutagenic activity reported previously was due to technical interference with the testing procedure by nonmutagenic materials in urine rather than the presence of mutagens. These observations may help clarify the interpretation of assays for urine mutagenicity in occupational or other environmental studies.
Temperature effects in the MONOS transistor

Abstract Metal-Oxide-Nitride-Oxide-Semiconductor (MONOS) memory transistors have been studied as a function of endurance cycling and elevated temperatures to determine the effects on memory window size and retention characteristics. Endurance cycling is shown to result in window loss and an increase in charge decay rate. Elevated temperatures enhance both of these degradation processes. However, following 10 9 cycles, the temperature dependence of decay rate is essentially masked by the damage caused by write/erase cycling. Following exposure to the most severe testing conditions (10 9 cycles at 175°C), the devices were still functional but the performance was significantly degraded.
Clinical presentation and outcomes of lymphocyte-predominant Hodgkin disease at the University of Florida.

Objective: To examine the clinical presentation and treatment outcomes of lymphocyte-predominant Hodgkin disease (LPHD) at the University of Florida over a 37-year period. Methods and Materials: A retrospective review of the clinical presentation and treatment outcomes in 34 patients with LPHD treated at the University of Florida from 1968 to 2005 was conducted. The end points of absolute survival, cause-specific survival, and relapse-free survival were assessed and late treatment sequelae were identified. Results: Ninety-six percent of patients presented with stage I/II disease. None had mediastinal disease, 4 (12%) had bulky disease (>6 cm in maximum tumor dimension), and only 1 (3%) had B symptoms. Eighty percent of patients were treated with radiation therapy (RT) alone and 20% with RT and chemotherapy. At 5, 10, and 15 years, absolute survival was 97%, 85%, and 76%; cause-specific survival was 100%, 95%, and 95%; and relapse-free survival was 93%, 81%, and 74%. No patients died with Hodgkin disease, but 1 patient's death was attributed to treatment-related late sequelae. There were 6 treatment failures, including 2 within the RT field; all failures were successfully salvaged. The median time to relapse was 5.8 years (range, 2.9–14.6 years). Three secondary malignancies were observed. Conclusion: LPHD patients typically present at an early stage without B symptoms, mediastinal, or bulky disease. First-line treatment with RT alone yields excellent results in appropriately selected patients and remains the standard of care. Relapses often occur late and long-term follow-up is needed to successfully diagnose and treat late relapses.
Can increased intra-abdominal pressure in humans be decoupled from trunk muscle co-contraction during steady state isometric exertions?

The purpose of the present study was to investigate whether increased intra-abdominal pressure (IAP) can be achieved without elevating the overall trunk muscle co-contraction that causes increased spine compression force. Ten subjects performed isometric trunk flexion, extension, and lateral bending exertions while generating 0%, 40% and 80% of their maximal IAP or while co-contracting trunk muscles without consciously raising IAP. An additional three subjects performed a variety of ramp IAP, co-contraction and isometric exertion tasks while holding their breaths and while exhaling. An 18 degree-of-freedom, electromyogram (EMG)-assisted biomechanical model was used to quantify trunk muscle co-contraction with calculations of spine compression force and stability. Spine stability and compression force increased proportionally with increased IAP regardless of whether the subjects intentionally generated IAP or consciously avoided it. This increase was accomplished with significantly greater co-contraction of 12 major trunk muscles. The EMG activation of all muscles was highly correlated with IAP and intra-thoracic pressure (ITP) (r from 0.59 to 0.95). Activity of the thoracic erector spinae correlated the best with ITP (r=0.81), which in turn was correlated with IAP (r=0.91). It was not possible to co-contract trunk muscles without generating IAP and ITP, or conversely to generate IAP without trunk muscle co-contraction and increased ITP.
Abeta40 is associated with cognitive function, body fat and physical fitness in healthy older adults.

Abstract Primary objectives: Body composition and obesity-related lifestyle factors are associated with increased risk for Alzheimer's disease (AD). Amyloid beta (Aβ) is a peptide integral in the pathogenesis of AD. Aβ has been shown to be related to body fat and exercise in younger adults; however, no study to date has examined the possible relationship among Aβ, body composition and fitness indices in older adults. Methods and procedures: Thirty-five older adults without significant neurological or psychiatric history, underwent fasting blood draw and completed cognitive testing and body composition and physical fitness assessments. Results: Partial correlations showed Aβ levels were inversely related to cognitive function, body fat and physical fitness measures. Conclusions: Findings indicate Aβ is associated with cognitive function, body fat and physical fitness in neurologically healthy older adults. Further work is needed to clarify possible mechanisms, particularly longitudinal studies.
Pharmacologic manipulation of human erythrocyte 2,3-diphosphoglycerate levels by prednisone administration.

Extract: Erythrocyte 2,3-diphosphoglycerate (2,3-DPG) concentrations in 10 patients with acute lymphoblastic leukemia rose 21.3% (P < 0.02) after 3 weeks of prednisone and vincristine therapy, and returned to pretreatment level 2 weeks after therapy had been discontinued. The mean 2,3-DPG level of three patients on vincristine alone did not vary significantly from the control level of the leukemia patients on prednisone and vincristine. No significant change in serum inorganic phosphate level was observed. The mean erythrocyte 2,3-DPG concentration of 17 nephrotic syndrome patients being treated with chronic prednisone therapy was 14.0% higher than a control group of 20 nephrotic syndrome patients not being treated with prednisone (P < 0.01). A significant positive correlation was observed between the dose of prednisone and 2,3-DPG level. Speculation: Human erythrocyte 2,3-DPG concentrations may be manipulated by pharmacologic doses of prednisone. Prednisone therapy may therefore be of potential benefit in clinical conditions characterized by decreased oxygen delivery to tissues.
Multi-scale temporal variation in water availability: Implications for vegetation dynamics in arid and semi-arid ecosystems

The objective of this paper is to illustrate the importance of variation in water availability to temporal variation in vegetation dynamics in arid and semi-arid ecosystems. We hypothesize that fine-scale pulses of precipitation interact with longer scale variation in climate and weather to generate temporal variation in plant community composition. Arid and semi-arid regions exhibit great temporal variability in water availability as a result of variation in climate and weather at multiple scales and vegetation-soil water feedbacks. The scales of variation include: shifting climate regimes over centuries and decades, inter-annual variation in weather patterns, seasonal differences in winter and summer precipitation, and within-season variability in precipitation frequency and magnitude. In arid and semi-arid regions, pulses of rainfall are separated by intervening dry periods of variable lengths. This situation results in fluctuating availability of water that limits plant production and controls other ecological processes, such as rates of nutrient cycling. In some semi-arid and arid systems, temporal variation in water availability may create positive feedbacks that facilitate encroachment of C3 woody plant species into areas formerly dominated by C4 grasses. Our ability to predict these complex shifts in vegetation composition may be improved by including temporal variation in climate, weather, and ecosystem processes.
Growing Smarter: Achieving Livable Communities, Environmental Justice, and Regional Equity edited by Robert D. Bullard

Robert D. Bullard (Ed.), Growing Smarter: Achieving Livable Communities, Environmental Justice, and Regional Equity (Cambridge, MA: MIT Press, 2007).Growing Smarter, edited by Robert Bullard, aims ...
Reciprocal effects between the perceived environment and heterosexual intercourse among adolescents.

This study proposes a transactional model for the reciprocal relationship between increased likelihood of adolescent sexual intercourse and decreased connection with the perceived environment. Connection with the perceived environment is operationalized as higher problem-focused interactions with parents, lower religious attendance, and lower school belonging. Relationship with the perceived environment is further hypothesized to explain the increase in depressive symptoms associated with initiating sexual intercourse in adolescence. Data from Waves 1 and 2 of the National Longitudinal Survey of Adolescent Health (one year apart; valid N=10,873) were analyzed using survey-adjusted multiple and logistic regression and path analysis. Hypothesized relationships were confirmed, with an additional finding that relationships with the perceived environment do not improve with the cessation of sexual intercourse. Implications of a possible explanation for this, that this finding indicates sexually active youth earn a stigmatized “non-virgin” label that they cannot easily remove, are discussed.
The information content of the forward premium and the forward forecast error

Abstract This paper investigates the ability of the forward premium and the forward forecast error to predict the conditional mean and the conditional variance of changes in the spot rate of three major dollar exchange rates namely, the Japanese yen, the German mark and the British pound. All three exchange rates are found to be cointegrated with the contemporaneous, as well as the lagged forward rate. The forward premium is found to contain important information that can be used to forecast the conditional mean of exchange rate changes, but, not the conditional variance. Similarly, the forward forecast error can be used to improve forecasts of the conditional variance, but, it is informationless with respect to the conditional mean. These findings hold for all three exchange rates under investigation.
Excimer laser mixing of nickel overlayers on silicon carbide

Abstract We have investigated mixing and alloying phenomena of nickel overlayers on silicon carbide induced by nanosecond laser pulses (wavelength 0.248 μm and pulse duration 35 ns) of a krypton fluoride laser. Rutherford backscattering results showed uniform mixing of nickel layers with Ni 84 Si 16 average chemical composition. Structural and chemical analyses were conducted by high-resolution and analytical electron microscopy techniques using cross-section (TEM) specimens. The results show the presence of amorphous and crystalline phases in the mixed layer. The details of these results are discussed.
Negotiating uncertainty: Framing attitudes, prioritizing issues, and finding consensus in the coral reef environment management crisis

Abstract Environmental problems are becoming increasingly unwieldy, particularly those which are highly debated because of their political and financial consequences and have been termed as in “crisis”. In coral reef environments, these considerations spill into decisions on mitigation of reef decline and attendant questions of territorial and resource-access rights. Historical foundations of reef science show that early applications of reef inquiries centered on environmental connection and inevitably led to establishing not only the baseline of reef ecosystems, but also contributed to the evolution of conservation crisis in this environment. This work applies Q-methodology towards determining attitudes, prioritizing statements and finding consensus regarding management issues that are tied to the science of coral reef environments and their conservation “crisis”. This work delineates the social construction of attitudes, perceptions, and foundations of coral conservation science by examining the scientifically-grounded statements that constitute conservation debates. Study participants were comprised of the coral reef science and conservation professional network. The Q-sample (n = 43) was structured around some central debates over the dilemmas and strategies of reef management and decline-mitigation, both recent and long-running. Four attitudes or viewpoints were isolated in terms of their preferred management models, geographic perspectives and the role scientific findings play within these core beliefs. These can be generally described as Community and Locally-centered Humanists, Scientific Idealists, Skeptical and Utilitarian Pragmatists, and Politically-oriented Positivists. Evaluating agreement about central issues showed a high degree of consensus regarding the relative importance of community input in the role of successful reef management while the highest degree of contention was seen in scalar issues such as human-environment feedback systems that are inherent in solving environmental crises.
NMR spectra of pseudotetrahedral molecules dissolved in a nematic liquid-crystal mixture

Abstract The proton magnetic resonance spectra for (CH3)4C and (CH3)(CD3)3C and the deuteron magnetic resonance spectra for (CD3)4C and (CH3)(CD3)3C have been obtained in nematic liquid-crystal mixtures over the temperature range 30 to 70°C. Each solution contained approximately 26 mole% solute, 55.5 mole% butyl-p(p-ethoxyphenoxycarbonyl)phenyl carbonate (BEPC), and 18.5 mole% p-(p-ethoxyphenylazo)-phenyl undecylenate (EPU). Proton-proton dipolar splittings were observed for (CH3)(CD3)3C but not for (CH3)4C, while both (CD3)4C and (CH3)(CD3)3C showed quadrupolar splittings. Analyses are discussed in which the dipole-dipole and the quadrupolar splittings are assumed to have additive contributions from both molecular alignment and orientation-dependent moleular distortion. The dipolar splittings indicate that the pseudo-C3 axis of (CH3)(CD3)3C is aligned with the favored direction of the nematic phase.
MRI of cerebral vein thrombosis in infancy: A case report

We diagnosed primary idiopathic cerebral vein thrombosis in an infant by MRI. The relative noninvasiveness of the scan, ease of imaging in multiple planes, and good image resolution suggest that the scan may be useful in this disorder.
Scattering from a periodic array of resistive strips

The problem of scattering from a resistive strip grating is formulated in the spectral domain. Results of numerical calculations of the reflection coefficient are presented for perfectly conducting strips and strips with resistivities up to 750\Omega /square.
The Relationship of the 96‐Hour LC50 to the Lethal Threshold Concentration of Hexavalent Chromium, Phenol, and Sodium Pentachlorophenate for Fathead Minnows (Pimephales promelas Rafinesque)

Abstract Short-term bioassays were conducted with adult fathead minnows and hexavalent chromium, phenol, and sodium pentachlorophenate at 2 temperatures to determine the relationship of the 96-hour LC50to the lethal threshold concentration. The lethal threshold concentration was less than the 96-hour LC50in 10 of 12 bioassays, was affected by temperature, and was not a constant multiple of the 96-hour LC50for any of the toxicants tested.
Electrical characterization of semiconducting diamond thin films and single crystals

Naturally occurring semiconducting single crystal (type IIb) diamonds and boron doped polycrystalline thin films were characterized by differential capacitance-voltage and Hall effect measurements, as well as secondary ion mass spectroscopy (SIMS). Results for natural diamonds indicated that the average compensation for a type IIb diamond was >17%. Mobilities for the natural crystals varied between 130 and 564 cm2/V·s at room temperature. The uncompensated dopant concentration obtained by C-V measurements (2.8 ± 0.1 × 1016 cm−3) was consistent with the atomic B concentration measured by SIMS performed on similar samples (3.0 ± 1.5 x 1016 cm−3). Measurement of barrier heights for three different metals (platinum, gold, and aluminum) found essentially the same value of 2.3 ± 0.1 eV in each case, indicating that the Fermi level was pinned at the diamond surface. Polycrystalline semiconducting diamond thin films demonstrated a complex carrier concentration behavior as a function of dopant density. This behavior may be understood in terms of a grain boundary model previously developed for polycrystalline silicon, or by considering a combination of compensation and impurity band conduction effects. The highest mobility measured for a polycrystalline sample was 10 cm2/V·s, indicating that electrical transport in the polycrystalline material was significantly degraded relative to the single crystal samples.
Correlates of hippocampal complex-spike cell activity in rats performing a nonspatial radial maze task

The observation of hippocampal place cells forms a major line of evidence supporting the view that the hippocampus is dedicated to spatial processing. However, most studies demonstrating the spatial properties of hippocampal unit activity have employed tasks that emphasize spatial cues but minimize nonspatial cues. In the present experiment we recorded the activity of hippocampal complex-spike cells from rats performing a nonspatial radial maze task. Performance in this task was guided by local visual-tactile cues on the maze arms, while distal spatial cues were minimized and made irrelevant. The influence of three variables on unit activity was examined:type of cue on an arm, spatial location of an arm, and the relative position of the animal on an arm. Of the units recorded, almost one-fifth were classified as “cue cells” in that their activity was associated with cue type but not spatial location. Conversely, a similar proportion of the units were classified as “place cells” in that their activity was associated with location, but not cue type. In an additional similar proportion of units, firing was influenced only by relative position and not by local cues or spatial locations. For the majority of units, however, firing was related to combinations of these three variables, indicating that most hippocampal neurons encoded conjunctions or relations between spatial and local cue information. This pattern of results indicates that when local rather than distal spatial cues are emphasized, hippocampal neural activity is strongly influenced by salient nonspatial cues and shows no overwhelming predominance of place coding. These findings are at odds with the hypothesis that the hippocampus is selectively involved in spatial processing and, conversely, support the broader view that the hippocampus encodes both spatial and nonspatial relations among important experimental variables.
Letter to the Glyco-Forum Glycoforms and biological activity: where's the rub?

I very much enjoyed Cumming's review article [Glycobiology, 1, (1991), pp. 115-130] dealing with the impact of glycosylation on recombinant glycoproteins. And in the main, I agree with much of what he says; however, there is one 'glycobiological' concept covered in his review which I find troubling and have personally retained some degree of skepticism about; the concept dealing with the biological role of glycoforms. Cumming discusses the general hypothesis that ensembles of differentially glycosylated species—each with its own modulated form of biological activity—could provide the organism with an impressive means for controlling biological function. The suggestion is that microheterogeneity provides the organism with an array of subpopulations displaying subtleties in activity—such as, say, slowand fast-acting forms of tPA—and other systemic properties such as targetting and sorting. And the elegant work performed recently by Baenziger and his coworkers on the glycoprotein hormones certainly points out one way in which differences in glycosylation can affect a biological property such as systemic half-life and receptor-mediated clearance. However, Baenziger has shown that this particular trait is not serendipitously provided for through the action of a 'Gaussian population' of glycoforms, but, rather, is encoded by the protein itself through the action of a unique tripeptide recognition sequence (signalling the action of a particular transferase). I personally expect, as Cumming asserts, that more of these glycosylation-processing instruction sets will appear, and this seems to me to be an eminently logical way for an organism to conserve particular glycosylation motifs which are crucial to the biological role of a glycoprotein.
Hysteresis model and magnetization of a radially anisotropic magnet ring

The paper describes a simplified vector hysteresis model developed for pulse magnetization of anisotropic permanent magnets. The model is tested on the magnetization of sintered and hot deformed anisotropic rings. The magnetization problem is solved by semianalytical and finite-element methods. The distribution of the magnetization vector is then imported in a static model to calculate a magnetic field around the ring. The predicted field is compared to the measured field in the open and closed magnetic circuits.
Time Dependent Adaptive Neural Networks

A comparison of algorithms that minimize error functions to train the trajectories of recurrent networks, reveals how complexity is traded off for causality. These algorithms are also related to time-independent formalisms. It is suggested that causal and scalable algorithms are possible when the activation dynamics of adaptive neurons is fast compared to the behavior to be learned. Standard continuous-time recurrent backpropagation is used in an example.
Cognitive networks for automated target recognition and autonomous system applications

It is shown that in order to be truly cognitive a network must be nonlinear and dynamical and able to manifest bifurcation. This means it should be able to carry out phase-space computations with more than one type of attractor and to switch between these depending on whether the sensory input is familiar or novel. Cognition therefore implies bifurcation and computing with diverse attractors. Reasons for adopting this view, which stemmed from known biophysical observations and from neuromorphic target identification work, are discussed. An example of a cognitive network that computes with both stationary (limit point) and dynamic (periodic) attractors is given to illustrate the thesis presented. The elements of a neuromorphic radar target identification system which employs these concepts and is capable of distortion-invariant recognition of three targets with perfect score are presented. The role of periodic attractors in feature binding and cognition and the significance of cognition in autonomous systems are elucidated. >
Simultaneous high-harmonic generation and raman lasing in a lithium niobate whispering-gallery resonator

We experimentally demonstrate simultaneous continuous-wave high-harmonic generation and Raman lasing in a periodically-poled lithium niobate whispering-gallery resonator, allowing spectral lines which span a 2-octave frequency band at a record-low pump power of 200mW.
UNCERT: geostatistics, uncertainty analysis and visualization software applied to groundwater flow and contaminant transport modeling

UNCERT is a 2D and 3D geostatistics, uncertainty analysis and visualization software package applied to ground water flow and contaminant transport modeling. It is a collection of modules that provides tools for linear regression, univariate statistics, semivariogram analysis, inverse-distance gridding, trend-surface analysis, simple and ordinary kriging and discrete conditional indicator simulation. Graphical user interfaces for MODFLOW and MT3D, ground water flow and contaminant transport models, are provided for streamlined data input and result analysis. Visualization tools are included for displaying data input and output. These include, but are not limited to, 2D and 3D scatter plots, histograms, box and whisker plots, 2D contour maps, surface renderings of 2D gridded data and 3D views of gridded data. By design, UNCERT’s graphical user interface and visualization tools facilitate model design and analysis. There are few built in restrictions on data set sizes and each module (with two exceptions) can be run in either graphical or batch mode. UNCERT is in the public domain and is available from the World Wide Web with complete on-line and printable (PDF) documentation. UNCERT is written in ANSI-C with a small amount of FORTRAN77, for UNIX workstations running X-Windows and Motif (or Lesstif). This article discusses the features of each module and demonstrates how they can be used individually and in combination. The tools are applicable to a wide range of fields and are currently used by researchers in the ground water, mining, mathematics, chemistry and geophysics, to name a few disciplines. # 1999 Elsevier Science Ltd. All rights reserved.
A boundary integral method to compute Green's functions for the radiative transport equation

The Green’s function for the time-independent radiative transport equation in the whole space can be computed as an expansion in plane wave solutions. Plane wave solutions are a general class of solutions for the radiative transport equation. Because plane wave solutions are not known analytically in general, we calculate them numerically using the discrete ordinate method. We use the whole space Green’s function to derive boundary integral equations. Through the solution of the boundary integral equations, we compute the Green’s function for bounded domains. In particular we compute the Green’s function for the half space, the slab, and the two-layered half space. The boundary conditions used here are in their most general form. Hence, this theory can be applied to boundaries with any kind of reflection and transmission law.
Structure and stability of complexes formed by nucleic acids. I. Binding of acridine to DNA

Nuclear magnetic resonance spectra of acridine have been measured in aqueous methanol solutions over a wide concentration range in the presence and absence of dissolved DNA. In solutions containing DNA the acridine spectra show a marked line broadening and intensity decrease at temperatures lower than 50°C. These line-shape changes can be associated with two types of binding interactions: (1) a tight, irrotational binding of the acridine at low acridine:phosphate ratios and (2) a weaker, rotationally less restrictive binding at high acridine concentrations. At temperatures above 50°C. a marked line narrowing is noted for the acridine spectrum and is attributed to an increase in mobility of the bound acridine as the DNA complex undergoes a helix–coil transition. A loose association of acridine molecules with the purine and pyrimidine bases in heat-denatured DNA is indicated by chemical shift changes in the acridine spectrum. The NMR measurements also show that the presence of acridine in denatured DNA solutions greatly reduces renaturation of the DNA.