cssi/SciSciGPT-SciSciNet huggingface dataset:
Perceived Depth in Natural Images Reflects Encoding of Low-Level Luminance Statistics

Sighted animals must survive in an environment that is diverse yet highly structured. Neural-coding models predict that the visual system should allocate its computational resources to exploit regularities in the environment, and that this allocation should facilitate perceptual judgments. Here we use three approaches (natural scenes statistical analysis, a reanalysis of single-unit data from alert behaving macaque, and a behavioral experiment in humans) to address the question of how the visual system maximizes behavioral success by taking advantage of low-level regularities in the environment. An analysis of natural scene statistics reveals that the probability distributions for light increments and decrements are biased in a way that could be exploited by the visual system to estimate depth from relative luminance. A reanalysis of neurophysiology data from Samonds et al. (2012) shows that the previously reported joint tuning of V1 cells for relative luminance and binocular disparity is well matched to a predicted distribution of binocular disparities produced by natural scenes. Finally, we show that a percept of added depth can be elicited in images by exaggerating the correlation between luminance and depth. Together, the results from these three approaches provide further evidence that the visual system allocates its processing resources in a way that is driven by the statistics of the natural environment.
Comparative analysis of neuropeptide cleavage sites in human, mouse, rat, and cattle

Neuropeptides are an important class of signaling molecules that result from complex and variable posttranslational processing of precursor proteins and thus are difficult to identify based solely on genomic information. Bioinformatics prediction of precursor cleavage sites can support effective biochemical characterization of neuropeptides. Neuropeptide cleavage models were developed using comprehensive human, mouse, rat, and cattle precursor data sets and used to compare predicted neuropeptide processing across these species. Logistic regression and artificial neural network models were used to predict cleavages based on amino acid and physiochemical properties of amino acids at precursor sequence locations proximal to cleavage. Correct cleavage classification rates across species and models ranged from 85% to 100%, suggesting that amino acid and amino acid properties have major impact on the probability of cleavage and that these factors have comparable effects in human, mouse, rat, and cattle. The variable accuracy of each species-specific model to predict cleavage sites indicated that there are species- and precursor-specific processing patterns. Prediction of mouse cleavages using rat models was highly accurate, yet the reverse was not observed. Sensitivity and specificity revealed that logistic models are well suited to maximize the rate of true noncleavage predictions with moderate rates of true cleavage predictions; meanwhile, artificial neural networks maximize the rate of true cleavage predictions with moderate to low true noncleavage predictions. Logistic models also provided insights into the strength of the amino acid associations with cleavage. Prediction of neuropeptide cleavage sites using human, mouse, rat, and cattle models are available at http://www.neuroproteomics.scs.uiuc.edu/neuropred.html .
Defect formation on the GaSb (001) surface induced by hydrogen atom adsorption

Abstract Density functional theory has been used to characterize the effects of adsorbed H on the electronic structure of the GaSb (001)-α(4×3) surface, which consists of a combination of Ga-Sb and Sb-Sb dimers. Adsorption of two H atoms at a Ga-Sb adatom dimer either has little effect on surface states above the bulk valence band maximum (VBM) or else eliminates them, depending on the mode of adsorption. However, adsorption at the Sb-Sb dimer in the terminating layer produces a state farther into the gap at ~0.10 eV above the clean-surface VBM. Relaxation accompanying the breaking of the Sb-Sb dimer bond leads to increased interactions involving three-fold-coordinated Sb sites in the terminating layer, which in turn raises the energies of the non-bonding lone-pair orbitals. This defect state, which appears to be unique to the reconstructed GaSb (001) surface, could potentially function as a hole trap on the surface of p -type GaSb.
Factor XIII deficiency: Concentrations inrelatives of patients and in normal infants

Since 1960 when Duckert and associates 2 observed a familial bleeding disorder caused by a deficiency of Factor XIII, 21 cases of Factor XIII deficiency, involving 10 families, have been reported. A 6-year-old boy with Factor XIII deficiency has been diagnosed and an assay technique with the patient's plasma as deficient substrate has been devised. In vivo survival studies, after transfusion of the patient with Factor XIII, indicate a half life of 5 to 7 days. Factor XIII assays in 50 infants and children from birth to 20 months of age reveal, a significantly lower level in the newborn infant and normal levels by 1 month of age. Factor XIII levels in the parents and siblings were significantly lower than in 20 normal individuals, suggesting an autosomal recessive inheritance of Factor XIII deficiency.
Fast synchronization recovery for lossy image transmission with a suffix-rich Huffman code

A new entropy codec, which can recover quickly from the loss of synchronization due to the occurrence of transmission errors, is proposed and applied to wireless image transmission in this research. This entropy codec is designed based on the Huffman code with a careful choice of the assignment of 1's and 0's to each branch of the Huffman tree. The design satisfies the suffix-rich property, i.e. the number of a codeword to be the suffix of other codewords is maximized. After the Huffman coding tree is constructed, the source can be coded by using the traditional Huffman code. Thus, this coder does not introduce any overhead to sacrifice its coding efficiency. Statistically, the decoder can automatically recover the lost synchronization with the shortest error propagation length. Experimental results show that fast synchronization recovery reduces quality degradation on the reconstructed image while maintaining the same coding efficiency.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Epidemiology of hypertension in African American women

To describe the epidemiology of hypertension in U.S. African American women and to highlight priority areas for future research, data from the nationwide surveys of the U.S. National Center for Health Statistics, from selected multicenter studies of the U.S. National Heart, Lung, and Blood Institute, as well as from selected other population-based studies, were reviewed. In 1988 through 1991, an estimated 3 million African American women aged 18 and older had hypertension. Compared with that in U.S. whites, hypertension in black women is characterized by higher incidence, earlier onset, longer duration, higher prevalence, and higher rates of hypertension-related mortality and morbidity. Risk factors for hypertension incidence in black women include obesity and weight gain. The effectiveness of drug therapy of hypertension has been established in black women, and important gains in rates of treatment and control have been accomplished. Nevertheless, rates of hypertension-related mortality for black women remain among the highest in the industrialized nations. Further research on causes and prevention of hypertension in black women is needed. Goals related to prevention and control of hypertension in African Americans for the year 2000 have been established and must be vigorously pursued.
A unified numerical analysis method for calculating dynamic wall-stress effects in pulsatile flow

Abstract A “Finite Element” method is developed for carrying out the direct numerical analysis of viscous hemodynamic flow in a long tube, under arbitrarily time-varying end pressures. The method yields directly the velocity and shearing stress profiles at the vessel walls. Results are checked with known profiles obtained by Womersley for sinusoidal input, and applied to experimental data furnished by Fry and Greenfield on measured aortic pressure gradients.
Stress buildup in ultraviolet-cured coatings: Sample thickness dependence

Stress buildup in ultraviolet radiation-induced coating can vary significantly as a function of processing conditions. Depending on radiation intensity and photoinitiator concentration, the average stress in the film may either increase or decrease with film thickness. On the basis of the current study on trimethylolpropane triacrylate (TMPTA) together with data reported previously, we conclude that the two main factors affecting stress in radiation curable coatings are (i) degree and distribution of cross-linking and (ii) temperature at solidification point. In certain experimental conditions, an uneven distribution of the conversion within the film may occur, leading to a decrease of the average film stress with increasing film thickness. In contrast, the temperature jump in the sample when irradiated may lead to an increase of the ultimate stress with film thickness.
An investigation of transient, two-dimensional coupled heat and moisture flow in the soil surrounding a basement wall

Abstract A two-dimensional finite difference numerical model has been developed to study coupled soil heat and moisture flow around an earth-sheltered construction. Simulations of a basement wall backfilled with a sand and a clay loam were performed. For the sandy soil, a 9% greater wall heat loss during the winter and an increase of over 40% in summer heat gain were observed when the coupling was modelled. The principle mechanism for the greater heat flow was the energy transported by the moisture flow from the ground surface. For the clayey soil, there was no difference between the coupled and uncoupled results.
Accounting for affective responses in video games

Recent scholarship in games suggests that communications design can offer a more critical approach to understanding and developing meaningful player experiences. In this paper, I analyze such experiences by examining the usability of The Arcade Wire: Airport Security in relation to its rhetorical aims as a game. Synthesizing two models for games analysis, I can develop a new model to more fully account for affective responses in player experience. Furthermore, the model itself can be reconfigured to examine different gamespaces that configure different relationships among their structural and phenomenlogical elements.
Associations between cognitive biases and domains of schizotypy in a non-clinical sample

Schizotypy is a non-clinical manifestation of the same underlying biological factors that give rise to psychotic disorders (Claridge and Beech, 1995). Research on normative populations scoring high on schizotypy is valuable because it may help elucidate the predisposition to schizophrenia (Jahshan and Sergi, 2007) and because performance is not confounded by issues present in schizophrenia samples. In the current study, a Confirmatory Factor Analysis was conducted using several comprehensive measures of schizotypy. As expected and replicating prior research, a four-factor model of schizotypy emerged including a positive, a negative, a cognitive disorganization, and an impulsive nonconformity factor. We also evaluated how each factor related to distinct cognitive biases. In support of hypotheses, increased self-certainty, decreased theory of mind, and decreased source memory were associated with higher scores on the positive factor; decreased theory of mind was associated with higher scores on the negative factor; and increased self-certainty was associated with greater impulsive nonconformity. Unexpectedly, decreased self-certainty and increased theory of mind were associated with greater cognitive disorganization, and decreased source memory was associated with greater impulsive nonconformity. These findings offer new insights by highlighting cognitive biases that may be risk factors for psychosis.
Stochastic Lattice Model Simulations of Molecularly Imprinted Polymers

A stochastic computer model was developed that simulates the formation and binding properties of molecularly imprinted polymers (MIPs). This simulation allowed examination of possible mechanisms in...
Vanadia Gel Synthesis via Peroxovanadate Precursors. 2. Characterization of the Gels

Vanadium oxide gels derived from the reaction of H2O2 and V2O5 have been investigated using 51V MAS NMR, TGA, XRD, SEM, and laser Raman spectroscopy. Based primarily on the 51V MAS NMR and TGA results, the coordinations of five distinct vanadia sites have been detailed, which possibly include a previously unreported dimer. The relative concentration of these sites changed as dehydration progressed, and a model of this process has been proposed based on the numerical analysis of the NMR MAS spectra. In addition, the coordination of the most tightly bound water has been postulated. Depending on sample treatment, it was possible to synthesize both layered and nonlayered materials. The laser Raman spectra revealed differences between layered and nonlayered materials. These differences have been attributed to the interaction of coordinated water molecules, which were trapped between layers and held firmly in place, thus restricting or altering certain Raman-active vibrations.
Effect of dietary change on the rates of synthesis and degradation of rat liver fatty acid synthetase.

Abstract Investigations were carried out to determine whether diet-induced changes in the level of rat liver fatty acid synthetase are due to changes in the rate of synthesis or degradation of this enzyme. Assays for radioactivity in fatty acid synthetase were carried out through isolation of the enzyme by a standard purification procedure or by immunoprecipitation with antiserum prepared specifically against rat liver fatty acid synthetase. Studies on the incorporation of radioactive leucine into the fatty acid synthetase during steady-state conditions showed that the relative rate of synthesis of this enzyme was decreased to one-fifth the normal value in the fasted state and increased to 14.3 times the normal value in rats refed a fat-free diet. Studies on the degradation of the fatty acid synthetase, reported as half-life of the enzyme, yielded identical values, 69 hr, for normal animals, as well as for animals refed a fat-free diet. The rates of synthesis of enzyme ( k s ) calculated from these half-life values and the enzyme content present in the liver in a given nutritional state agreed well with the relative rates of synthesis. On the basis of these results it is concluded that changes in the level of liver fatty acid synthetase which are diet induced are due primarily to changes in the rate of synthesis rather than degradation of this enzyme. However, transient changes in the rate of degradation may also be important during the transition period, particularly in the case of fasting.
Spectral analysis of forest model time series

Abstract The use of spectral analysis to elucidate the cyclic behavior in time series generated by a forest stand growth simulation model is discussed. A stand-level simulator, FORET, for an Appalachian deciduous forest is described. An estimate of the power spectral density of the total biomass time series is calculated. The power spectral density estimate indicates a dominant cyclic behavior with a period of about 200 years. In addition the spectral density is approximately bandlimited. This characteristic makes possible the application of the sampling theorem for analysis of sampling rates.
Great Expectations Examining the Discrepancy Between Expectations and Experiences on College Student Retention

The purpose of this article is to build upon previous efforts evaluating the degree to which the discrepancy between student expectations and experiences can result in greater rates of attrition in...
Revisiting the experimental and theoretical upper bounds of light pure gas selectivity–permeability for polymeric membranes

Abstract Robeson [L.M. Robeson, J. Membr. Sci. 62 (1991) 165–185] described “upper bounds” correlating the pure gas selectivity with the permeability of the faster gas, P A . The exponential dependence of the selectivity–permeability trade off, −1/ n , according to the relationship α A / B = P A / P B = k − 1 / n P A 1 / n , was shown to be a function of the difference in the kinetic diameter of the gas pairs, Δ A/B = d B − d A . Robeson recently revisited the upper bounds [L.M. Robeson, J. Membr. Sci. Available online 22 April 2008], adding two new gas pairs, CO 2 /N 2 and N 2 /CH 4 and, with only minor changes to the slopes of the upper bounds, confirmed the relationship between −1/ n and Δ A/B . Significant changes were reported for the front factor k . Freeman [B.D. Freeman, Macromolecules, 32(1999) 375–380] developed a theoretical model which describes these upper bounds as a function of a reduced kinetic diameter, λ A / B = ( d B / d A ) 2 − 1 and α A / B = β A / B P A − λ A / B . The theoretical model opened the possibility of setting upper bounds for gas pairs for which experimental upper bounds were not reported. Despite quantitative predictions of both −1/ n and k −1/ n (or β A/B ) calculated values of α A/B compared poorly with Robeson's upper bounds for many of the gas pairs. This work revisits Robeson's findings as well as those of Freeman and seeks to improve the predictive accuracy of Freeman's model. Robeson had noted that the low precision of many of the kinetic gas diameters could have contributed to the scatter in his correlation of −1/ n and Δ A/B . Considering this hypothesis, the gas diameters were re-estimated using the Error in the Variable Method (EVM) with the regression criterion based on the predicted selectivity at three permeabilites compared to Robeson's upper bounds. Very small changes to the gas diameters, typically λ A/B = −1/ n . Freeman's f value, a constant in the E D correlation as a function of the gas collision diameter, was revised from 12,600 to 16,909 cal mol −1 (52.7 to 70.7 KJ mol − 1). Recent predictions of the theoretical upper bound are reviewed and corrections proposed based on Freeman's model and parameters for the gas pairs: N 2 /CH 4 and CO 2 /N 2 .
Husbandry of Monodelphis domestica in the study of mammalian embryogenesis

Monodelphis domestica, commonly called the laboratory opossum, is a useful laboratory animal for studying marsupial embryogenesis and mammalian development. Females breed year-round and the animals can be sustainably bred indoors. The authors draw on their own laboratory's experience to supplement previously published research on laboratory opossums. They describe a breeding protocol that reliably produces timed-pregnant M. domestica. Additionally, the authors discuss general laboratory opossum husbandry techniques and describe how to collect, handle and culture embryos.
The effect of hypertonic sodium chloride on intracranial pressure in patients with acute liver failure

Acute liver failure (ALF) is a rare condition characterized by the development of encephalopathy in the absence of chronic liver disease. Cerebral edema occurs in up to 80% of patients with Grade IV encephalopathy. In the current prospective randomized controlled clinical trial, we examined the effect of induced hypernatremia on the incidence of intracranial hypertension (IH) in patients with ALF. Thirty patients with ALF and Grade III or IV encephalopathy were randomized. Patients in Group 1 (n = 15) received the normal standard of care. Patients in Group 2 (n = 15) received standard care and hypertonic saline (30%) via infusion to maintain serum sodium levels of 145-155 mmol/L. Intracranial pressure (ICP) was monitored in all patients with a subdural catheter (Camino Systems, San Diego, CA) for up to 72 hours after inclusion. Serum sodium levels became significantly different from the levels observed in the control group at 6 hours (P <.01). Over the first 24 hours, norepinephrine dose increased relative to baseline in the control group (P <.001; 13 patients) but not in the treatment group. ICP decreased significantly relative to baseline over the first 24 hours in the treatment group (P =.003; 13 patients) but not in the control group. The incidence of IH, defined as a sustained increase in ICP to a level of 25 mm Hg or greater, was significantly higher in the control group (P =.04). In conclusion, induction and maintenance of hypernatremia can reduce the incidence and severity of IH in patients presenting with ALF.
Study of the XeCl laser pumped by a high-intensity electron beam

We present the results of a detailed experimental study of the XeCl laser pumped by a high-intensity electron beam. The laser system was optimized as an oscillator for mixtures of Xe and HCl with Ne, Ar, and Kr diluents. The peak intrinsic efficiency (laser energy out/electron-beam energy deposited) was near 4.5 percent for each of these diluents. Small-signal gain and background absorption were measured as a function of electron-beam deposition rate from 0.4 to 6 MW/ cm3. The ratio of small-signal gain to absorption was found to be constant over this range with a value of ∼5. Measurements of absorption in the presence of a large photon flux indicated that there was no appreciable saturable contribution to the absorption. Measurements of fluorescence from the B and C states indicate that collisional mixing between these states is very rapid. The formation efficiencies of the B and C states are estimated to be 0.15 and 0.05, respectively. A vibrational relaxation rate of between 1 and 1.5 \times 10^{-10} cm3. s-1was determined. The effect of this finite relaxation rate is to reduce the energy available to the stimulated process by a factor of 0.67-0.75. Estimates of the XeCl* deactivation rates by HCl and electrons were also obtained. A value of 1.7 \times 10^{-9} cm3. s-1was obtained for quenching by HCl, and a value of \sim 1 \times 10^{-7} cm3. s-1was estimated for electron deactivation.
Calorimetric Studies of Precipitation and Dissolution Kinetics in Aluminum Alloys 2219 and 7075

Differential scanning calorimetry (DSC) was used to study the kinetics of precipitation and dissolution of metastable and stable phases in aluminum alloys 2219 and 7075. A comparison of DSC scans obtained at heating rates of 1, 5, 10, and 20 K per minute showed that, during a DSC scan, the rates of precipitation of θ′ and θ in 2219 and η′ and η in 7075 were limited by their reaction kinetics. Likewise, the rates of dissolution of GP zones, θ′ and η′, were found to be dominated by kinetics. In contrast, the dissolution of θ and η was dominated by the thermodynamic equilibrium between these phases and the matrix. Analysis of the kinetically dominated reaction peaks and their dependence on heating rate and particle size showed that the GP zone dissolution reaction could best be described by a three-dimensional volume diffusion limited rate expression with an activation energy equal to that for diffusion. The rate of formation of θ′ was best described by an Avrami expression withn = 1.1, indicating that nucleation was not the rate controlling step. A pronounced dependence of the θ′ formation rate on prior plastic deformation was observed and ascribed to the influence of the matrix dislocation density on diffusivity.
Spatial vision in the purple sea urchin Strongylocentrotus purpuratus (Echinoidea)

Recent evidence that echinoids of the genus Echinometra have moderate visual acuity that appears to be mediated by their spines screening off-axis light suggests that the urchin Strongylocentrotus purpuratus, with its higher spine density, may have even more acute spatial vision. We analyzed the movements of 39 specimens of S. purpuratus after they were placed in the center of a featureless tank containing a round, black target that had an angular diameter of 6.5 deg. or 10 deg. (solid angles of 0.01 sr and 0.024 sr, respectively). An average orientation vector for each urchin was determined by testing the animal four times, with the target placed successively at bearings of 0 deg., 90 deg., 180 deg. and 270 deg. (relative to magnetic east). The urchins showed no significant unimodal or axial orientation relative to any non-target feature of the environment or relative to the changing position of the 6.5 deg. target. However, the urchins were strongly axially oriented relative to the changing position of the 10 deg. target (mean axis from -1 to 179 deg.; 95% confidence interval +/- 12 deg.; P<0.001, Moore's non-parametric Hotelling's test), with 10 of the 20 urchins tested against that target choosing an average bearing within 10 deg. of either the target center or its opposite direction (two would be expected by chance). In addition, the average length of the 20 target-normalized bearings for the 10 deg. target (each the vector sum of the bearings for the four trials) were far higher than would be expected by chance (P<10(-10); Monte Carlo simulation), showing that each urchin, whether it moved towards or away from the target, did so with high consistency. These results strongly suggest that S. purpuratus detected the 10 deg. target, responding either by approaching it or fleeing it. Given that the urchins did not appear to respond to the 6.5 deg. target, it is likely that the 10 deg. target was close to the minimum detectable size for this species. Interestingly, measurements of the spine density of the regions of the test that faced horizontally predicted a similar visual resolution (8.3+/-0.5 deg. for the interambulacrum and 11+/-0.54 deg. for the ambulacrum). The function of this relatively low, but functional, acuity - on par with that of the chambered Nautilus and the horseshoe crab - is unclear but, given the bimodal response, is likely to be related to both shelter seeking and predator avoidance.
Preparation, Evaluation and Analysis of a French-Fry-Type Product from Sweet Potatoes

A French-fry-type product was prepared from ‘Jewel’ and ‘Centennial’ sweet potatoes. Samples were prepared from freshly harvested, cured, and stored, cured roots. The roots were peeled, sliced into strips and blanched in hot water. The blanched strips were partially dehydrated by one of five treatments and then frozen at −30°C. Frozen strips were fried in hot peanut oil and evaluated by a sensory panel. Strips prepared by dehydration in a hot air tunnel at 120°C for 5 min were favored by the sensory panel. Blanching removed significant amounts of dry matter and resulted in partial hydrolysis of the starch by endogenous enzymes. Sensory color scores were not affected by reducing sugar content. Sensory flavor scores were related to total sugar content.
Association of Ld-restricted peptides with the wild-derived mouse Lw16 MHC class I molecule

Abstract Previous serological analysis of untreated splenocytes and L cell transfectants expressing the wild-derived mouse major histocompatibility complex (MHC) class I molecule, L w16 , demonstrated the presence of two forms of this molecule in the cell lysates, one reactive with both the α2 domain-reactive monoclonal antibody (mAb) 30-5-7 and the α3 domain-reactive rnAb 28-14-8 (30-5-7 + 28-14-8 + ), and the other reactive with only the latter of the two (30-5-7 − 28-14-S + ). Furthermore, the analysis suggested the presence of both forms on the cell surface. Due to the similarity of L w16 to the inbred mouse-derived L d molecule, we tested a panel of L d restricted and control peptides for their ability to bind to L w16 molecules. Here, we report that two L d restricted viral peptides, lymphocytic choriomeningitis virus nucleoprotein (LCMV NP) 118–126 and murine cytomegalovirus (MCMV) pp89 168–176, significantly increase the number of L w16 molecules on the cell surface as measured by the mAb 28-14-8, and the proportion of those molecules that are recognized by the mAb 30-5-7. This was further supported by an increase in mAb 30-5-7-reactive molecules in L.L w16 cell lysates following treatment with either of these peptides. Examination of the stability of the different forms on the cell surface suggested that the 30-5-7 + L w16 molecules induced with these peptides were unstable and probably lost their L d -restricted peptides to generate 30-5-7 − 28-14-8 + molecules; these latter molecules were also unstable. In contrast, putative 30-5-7 + and 30-5-7 − 28-14-8 + L w16 molecules on untreated cells were stable. Together, these results suggest that two L d restricted, viral peptides can induce assembly of or stabilize 30-5-7 + 28-14-8 + L w16 molecules, mimicking endogenous self peptides. However, the association of the L d -restricted peptides with L w16 is apparently not optimal, since it results in unstable L w16 molecules.
Human issues and LIMS: the impact on quality

Abstract Long, T.J., 1992. Human issues with LIMS: the impact on quality. Chemometrics and Intelligent Laboratory Systems: Laboratory Information Management, 17: 289–294. Many laboratories implement a laboratory information management system (LIMS) to improve laboratory quality. The systems model suggests that by looking at the laboratory as a set of subsystems, laboratory system behavior can be better understood. The human subsystem plays a key role in laboratory performance. Among the important qualities of the human subsystem are individual attitudes toward innovation and motivation. Individuals can be grouped into five categories based upon their attitudes toward innovation. These categories suggest how to assign key responsibilities. Factors which motivate individuals can be used to facilitate implementation of a LIMS. The combining of individual behavior into group behavior suggests a team structure for project performance. Finally, management performs a critical role in guiding and providing a framework for the human subsystem to facilitate LIMS performance.
Phase-invariant solutions of nonlinear wave-wave interacting systems

Abstract The existence of phase-invariant solutions for a class of nonlinear wave-wave interacting systems is studied. These solutions have the property that the phase of each wave is invariant with time or unaffected by the nonlinear interactions. Explicit results are obtained for certain two-wave and three-wave systems. It is shown that for these systems, the wave-energy transfer along the phase-invariant solutions is always unidirectional. The application of these results to the non-inear interaction between two transverse waves and a longitudinal wave in a magnetized collisionless plasma is discussed.
Design and characterization of a grating-assisted coupler enhanced by a photonic-band-gap structure for effective wavelength-division demultiplexing

We report a novel grating-assisted coupler that incorporates a photonic-band-gap structure. It is shown that by virtue of the resonant cavity formed by the structure and the grating the relative amounts of the output scattered and the transmitted guided-wave powers can be significantly modified. The potential applications for optical switches and wavelength demultiplexers based on this new configuration are discussed.
Parvovirus-Mediated Fetal Cardiomyopathy With Atrioventricular Nodal Disease

Acute parvovirus B19 infection (API) in pregnancy has been associated with fetal anemia and hydrops fetalis. Direct myocardial damage from API in a fetus and an infant has been described. This report presents a case of fetal second-degree heart block and cardiomyopathy secondary to API. A 19-year-old G4P1112 (gravida 4 para 2 with 1 term delivery, 1 preterm delivery, 1 termination, and 2 living children) was referred at 20 weeks gestation for fetal bradycardia. A 2:1 atrioventricular block was identified by fetal echocardiography at 23 weeks. Hydrops developed at 25 weeks. Amniocentesis and percutaneous umbilical blood sampling demonstrated API. At 31 weeks, the patient presented with preterm labor and delivered a viable female infant, who died of poor cardiac function and arrhythmia on the first day of life. In addition to fetal anemia and hydrops fetalis, API in pregnancy may cause direct fetal myocardial damage and conduction system disease.
Effect of physician specialty on use of necessary coronary angiography

Objectives. This study sought to determine whether having a cardiologist as a regular source of care influences likelihood of undergoing necessary coronary angiography. Background. An important element of the current health policy debate is the respective roles of primary care and specialist physicians. However, there are few data on interspecialty differences in quality of care for patients with ischemic heart disease. Methods. We contacted 243 patients by telephone (response rate 72%) who had positive (or very positive) exercise stress test results and met additional clinical criteria for necessary coronary angiography. Study patients were randomly sampled from those undergoing exercise stress testing at one university and three public hospitals in Los Angeles between January 1, 1990 and June 30, 1991. Patients were asked whether they had a regular source of care during the time after their exercise stress test and, if so, whether that provider was a cardiologist or cardiology clinic. Results. Among survey responders, 47% underwent necessary coronary angiography within 3 months of exercise testing and 61% within 12 months. After adjustment for sociodemographics and clinical presentation, patients with a cardiologist as a regular source of care were more likely than all other patients to have undergone necessary angiography within 3 months (52% vs. 38%, p = 0.05) and within 12 months (74% vs. 44%, p = 0.0001) of the exercise test. At 3 months, there was a trend toward a more pronounced effect of ongoing cardiologic care within the public hospitals compared with the private hospital (p = 0.09 for interaction between hospital types). Conclusions. Patients with a cardiologist as a regular source of care were more likely than all other patients to undergo clinically necessary coronary angiography within both 3 and 12 months of exercise stress testing.
Detection of secretion from pancreatic islets using chemically modified electrodes

Abstract Secretion of insulin from pancreatic islets was monitored indirectly by detecting zinc. Anodic stripping voltammetric measurements of zinc were done on a bismuth-modified electrode. Comparison of the performance of bismuth-modified electrodes and mercury film electrodes showed that bismuth is an appropriate alternative for Zn detection. The bismuth-coated electrode was used to detect zinc in insulin samples and insulin secreted from pancreatic islets upon stimulation with high concentrations of K + . Detection of zinc released from pancreatic islets was done in the culture medium without any further cleanup. This detection method can be used to monitor secretion from pancreatic islets in their native environment.
Non-isothermal effects in a single pellet diffusion reactor

Abstract A theoretical analysis of an adiabatic non-isothermal single-pellet diffusion reactor shows that non-isothermal effects can alter the value of the centerplane concentration. Deviation from isothermal behavior is significant under exothermic conditions where multiplicity of solutions can lead to reactor instabilities or falsification of reaction parameters. Conversely, it is shown that the internal isothermal model is a good approximation to detect non-isothermal pellet behavior from centerplane concentration measurements.
The influence of cigarette smoking on circulating concentrations of antioxidant micronutrients.

Abstract Cigarette smoke is a significant source of oxidative stress, one potential mechanism for its untoward health effects. The antioxidant defense system is partly comprised of antioxidant micronutrients, making it important to understand the relationship between cigarette smoking and circulating concentrations of antioxidant micronutrients. A synthesis of the literature shows that compared with nonsmokers, on average, active smokers have greater than 25% lower circulating concentrations of ascorbic acid, α-carotene, β-carotene, and cryptoxanthin. The differences in blood concentrations of these micronutrients in former smokers is intermediate between never and current smokers, but average circulating concentrations of α-carotene, β-carotene, and cryptoxanthin were 16–22% lower in former smokers compared with never smokers. Differences in dietary habits between smokers and nonsmokers could potentially account for these associations. Dietary micronutrient intake is associated with blood micronutrient concentrations. Furthermore, patterns of micronutrient consumption by smoking status mimic the pattern of associations observed for blood concentrations. For example, when pooled across studies intake of vitamin C was 16% lower in current smokers and 2% lower in former smokers than in never smokers; the corresponding figures for β-carotene were 17 and 4%, respectively. Despite the strong potential for confounding, the differences observed between current smokers and nonsmokers seem to be due to an acute effect of smoking based on results of studies of smoking and antioxidant micronutrient concentrations that have either adjusted for dietary antioxidant micronutrient intake and other potential confounding factors or documented short term changes in circulating antioxidant micronutrient concentrations in smokers before and after smoking cigarettes. The associations observed with active smoking also appear to hold true for passive smoking, implying that even low-dose exposures to tobacco smoke can result in lowered circulating antioxidant micronutrient concentrations. Smoking was more weakly associated with circulating concentrations of vitamin E and the nonprovitamin A carotenoids lutein/zeaxanthin and lycopene. The combined evidence supports the conclusion that cigarette smoking is independently associated with lowered circulating concentrations of ascorbic acid and provitamin A carotenoids. These associations have implications for the design and interpretation of epidemiologic studies of antioxidant micronutrients in relation to health and disease. To the extent that these micronutrients are associated with health and longevity, this evidence documents yet another deleterious consequence of cigarette smoking on human health.
How Long Is Long Enough When Measuring Fluxes and Other Turbulence Statistics

Abstract It is determined how long a time series must be to estimate covariances and moments up to fourth order with a specified statistical significance. For a given averaging time T there is a systematic difference between the true flux or moment and the ensemble average of the time means of the same quantities. This difference, referred to here as the systematic error, is a decreasing function of T tending to zero for T→∞. The variance of the time mean of the flux or moment, the so-called error variance, represents the random scatter of individual realizations, which, when T is much larger than the integral time scale T of the time series, is also a decreasing function of T. This makes it possible to assess the minimum value of T necessary to obtain systematic and random errors smaller than specified values. Assuming that the time series are either Gaussian processes with exponential correlation functions or a skewed process derived from a Gaussian, we obtain expressions for the systematic and random e...
Myocardial perfusion imaging analysis in patients with regurgitant valvular heart disease

We noticed that there was decreased correlation of the findings from myocardial perfusion imaging (MPI) and cardiac catheterization (CATH) in patients with mitral regurgitation (MR) and aortic regurgitation (AR) compared to patients without valve disease. Through a systematic review of MPI records at the Harry S. Truman Memorial Veterans’ Hospital between 1998 and 2008, we identified 58 patients with at least moderate MR or AR by echocardiogram who underwent cardiac catheterization within 6 months of the MPI study. A control group was formulated with 60 patients who did not have significant MR or AR on echocardiogram and who had both MPI and CATH. Correlation between MPI and CATH was graded as complete, partial, or absent. Correlation between MPI and CATH was lower in the valve disease patients (study group) when compared to controls. Correlation was complete in 76% of study patients and 90% of controls, partial in 15% of study patients and 5% of controls, and absent in 9% of study patients and 5% of controls. Differences between the groups were significant (P < .05). Patients with regurgitant valvular heart disease may have myocardial perfusion abnormalities that are not associated with angiographic critical coronary stenosis.
Explantation of patent foramen ovale closure devices: a multicenter survey.

Objectives The aim of this study was to examine the frequency and causes of surgical explantation of patent foramen ovale (PFO) closure devices. Background PFO has been linked with cryptogenic strokes, recurrent transient neurologic deficits, sleep apnea, decompression illness, and migraines. Several randomized trials are in progress to determine whether PFO closure is preferable to medical management in the treatment of patients with cryptogenic strokes or migraine. The majority of PFO closures are performed off-label, because there is no U.S. Food and Drug Administration approval for use of any device to close a PFO. As data are accumulating on the benefits of implanting PFO closure devices, it is also important to examine complications that might occur. Methods We performed a database review to identify the frequency and causes of PFO device explantation, examining 18 PFO closure centers in Europe and the United States. Results Of the 13,736 percutaneous PFO device implantations performed over the past 9 years at these 18 institutions, 38 devices (0.28% [95% confidence interval: 0.20% to 0.37%]) required surgical removal. There were a wide range of causes cited for these removals. The most common cause for explantation was chest pain (n = 14), often determined to be secondary to nickel allergy to the PFO device. Other causes for explantation included persistence of a residual shunt (n = 12), the presence of thrombus on the device (n = 4), pericardial effusion (n = 2), perforation of the atrium or aortic root (n = 2), recurrent strokes (n = 1), the development of endocarditis (n = 1), and undocumented reasons (n = 2). Conclusions The vast majority of PFO closure procedures are performed safely with minimal complications. However, there is a small (0.28%) incidence of severe long-term problems associated with PFO closure that might require surgical removal of the device. In addition, the frequency of surgical explantation was found to be device-dependent; some of these devices seem to be safer than others.
Measurements for active cigarette smoke exposure in prevalence and cessation studies: Why simply asking pregnant women isn't enough

Tobacco smoke exposure during and after pregnancy may cause maternal, fetal, and infant morbidity and mortality. The purpose of this review is to (a) describe existing methods of measuring active tobacco exposure among pregnant women and (b) illustrate the usefulness of these measures in validating self-reported smoking status among these women. Medline, PsycINFO, and Academic Search Elite were used to identify measures of cigarette smoking exposure, prevalence reports, cessation and validity studies, and research on deception about smoking during pregnancy. Review of the research on smoking cessation among pregnant women since 1966 revealed that 36% of studies (9 out of 25) located used only self-report to assess smoking status. The remaining 16 studies used either significant other reports or at least one type of biochemical test to confirm self-report. Deception rates were reported at baseline only, follow-up only, or both in 15 studies. Three federal agencies in the United States collect data on self-reported smoking during pregnancy. Smoking prevalence rates are inconsistent among these agencies. This article demonstrates that measuring smoking status during pregnancy via self-report alone leads to discrepancies in national prevalence rates, deceptions in clinical practice disclosure, and inconsistencies in research study results. Evaluation studies that confirm smoking status among pregnant women by biochemical methods provide more accurate prevalence rates and lead to the most effective behavioral interventions to achieve cessation. National statistics should carry a disclaimer indicating the likelihood of underestimation. Researchers and clinicians should be trained in best-practice, evidence-based behavioral methods to assess prenatal smoking status and to assist those who desire to quit.
The Effects of Unequal Reward Distributions on Cooperative Problem Solving by Cottontop Tamarins (Saguinus oedipus).

Cooperation among non-human animals has been the topic of much theoretical and empirical research, but few studies have examined systematically the effects of various reward payoffs on cooperative behaviour. Here, we presented heterosexual pairs of cooperatively breeding cottontop tamarins with a cooperative problem solving task. In a series of four experiments, we examined how the tamarins’ cooperative performance changed under conditions in which (a) both actors were mutually rewarded, (b) both actors were rewarded reciprocally across days, (c) both actors competed for a monopolizable reward and (d) one actor repeatedly delivered a single reward to the other actor. The tamarins demonstrated sensitivity to the reward structure, exhibiting the greatest percentage of trials solved and shortest latency to solve the task in the mutual reward experiment and the lowest percentage of trials solved and longest latency to solve the task in the experiment in which one actor was repeatedly rewarded. However, even in the experiment in which the fewest trials were solved, the tamarins still solved 46 ± 12% of trials and little to no aggression was observed among partners following inequitable reward distributions. The tamarins did, however, exhibit selfish motivation in each of the experiments. Nevertheless, in all experiments, unrewarded individuals continued to cooperate and procure rewards for their social partners.
DIEL AND SEASONAL ACTIVITY PATTERNS OF PYGMY RABBITS (BRACHYLAGUS IDAHOENSIS)

Characterizing circadian activity patterns is one of the essential steps to understanding how a species interacts with its environment. This study documented activity patterns of pygmy rabbits (Brachylagus idahoensis) in free-ranging populations at 5 sites in Nevada and California. Infrared-triggered camera systems were placed within areas occupied by populations of pygmy rabbits and operated for 1 year. The number of photographs obtained per hour was used as an index of aboveground activity. Activity was analyzed for diel and seasonal patterns as well as for differences among populations. All populations showed a bimodal diel activity pattern with most activity occurring at dawn and at dusk during all seasons. Greatest activity occurred at dawn except during winter. Four of the 5 study sites showed similar levels of activity. The atypical site was located 550 m higher in elevation at a locality known for extreme weather; activity levels were twice as high at that site. Activity patterns of pygmy rabbits likely reflect a combination of predation pressures as well as metabolic energy demands.
Toward precision polarimetry of dense polarized 3He targets

Abstract We describe several new measurement and analysis techniques used to determine the polarization of the 3He target in a recently completed measurement of the neutron spin structure function g 1n at SLAC (E-154). The polarization was determined using two independent methods. The first method used a standard technique of Adiabatic Fast Passage, calibrated by a measurement of Boltzmann polarization in a sample of water. We describe several systematic effects affecting this calibration procedure. The second method used a shift of the Rb Zeeman resonance frequency due to the polarization of 3He. Implementation and calibration of this technique are discussed in detail. Finally, the density of 3He in the cell was measured using two independent methods, one of them based on the pressure broadening of Rb D1 and D2 lines due to 3He.