cssi/SciSciGPT-SciSciNet huggingface dataset:
Pharmacokinetic modeling of disposition and time-course studies with [14C]atrazine.

A physiological pharmacokinetic (PPK) model, with blood, body, and brain compartments, was developed to estimate total plasma chlorotriazine (CI-TRI) time courses (i.e., atrazine [ATRA] and its three chlorinated metabolites) after oral dosing with ATRA. The model, based on disposition data for 14C-ATRA, tracked two pools of compounds: (1) ATRA and chlorinated metabolites (i.e., the CI-TRIs) and (2) glutathione conjugates. The PPK model developed from total radioactivity was valuable for assessing total plasma CI-TRI concentrations, estimating blood protein binding rates of CI-TRIs, and inferring relationships between tissue exposures of CI-TRIs and administered dose. Absorption of radioactivity into plasma was slow with a rate constant of 0.2 h-1. 14C-disposition data indicated that CI-TRIs react with red blood cells (presumably hemoglobin) and plasma proteins. Second-order rates of reaction of CI-TRIs with hemoglobin and plasma protein were estimated to be 0.008 L/mmol/h and 1.14 x 10(-7) L/mg/h, respectively. A time-course study, conducted as part of this study, evaluated the absorption, disposition, and elimination characteristics of individual CI-TRIs in plasma after a single oral dose of 90 mg ATRA/kg and indicated (1) that slow uptake into blood reflected both absorption and slow dissolution of the ATRA slurry and (2) that diaminochloro-s-triazine (DACT) was the major, persistent plasma CI-TRI after oral dosing. Optimally, PK model development for pesticide compounds like atrazine should include a combination of radiolabeled studies for residues and speciation studies of important metabolites.
A comparison of groundwater fluxes computed with MODFLOW and a mixing model using deuterium: Application to the eastern Nevada Test Site and vicinity

Summary The primary objective of this study was to verify groundwater flows in the vicinity of the eastern Nevada Test Site (NTS) computed with a hydraulically defined flow model against groundwater δD values computed by a steady-state mixing model. The United States Geological Survey’s Death Valley regional flow model (DVRFM) is a transient, three-dimensional, groundwater model that uses the public domain, finite-difference code MODFLOW. The mixing model (Discrete-State Compartment Model-Shuffled Complex Evolution, or DSCM-SCE) is a recently developed code that is able to autocalibrate groundwater fluxes (both magnitude and direction) to best match observed tracer concentrations in groundwater. To compare modeling approaches, DVRFM boundary conditions and cell-to-cell interactions were implemented into a previously developed 15-cell DSCM-SCE δD model of the eastern NTS. Analysis of δD and δ18Ο data conducted throughout the model domain suggests recharge and mixing are the dominant mechanisms for groundwater isotopic enrichment in the downgradient direction. Therefore, evaporation, at least at the regional scale, was ignored. Model results showed that DVRFM boundary fluxes and cell outflow volumes reproduced observed groundwater δD values in nine of the 11 hydrographic basins that contained deuterium data. The remaining four modeled basins did not have any deuterium data, however, modeling results closely matched estimated δD for two of these basins. The isotope mixing model independently verified that most of the hydraulically defined groundwater flows simulated by MODFLOW are reasonable. Optimization of the DSCM-SCE was then done by adjusting groundwater fluxes between cells to improve predicted groundwater δD values. This significantly lowered the weighted root-mean-squared error and helped to identify several basins where DVRFM–simulated boundary conditions and groundwater fluxes should be reexamined. Overall, the two modeling approaches complemented each other, such that the isotope mixing model verified the hydraulically based groundwater flow model and refined groundwater flux estimates to better understand the physical system.
The NASA-Langley Wake Vortex Modelling Effort in Support of an Operational Aircraft Spacing System

Two numerical modelling efforts, one using a large eddy simulation model and the other a numerical weather prediction model, are underway in support of NASA's Terminal Area Productivity program. The large-eddy simulation model (LES) has a meteorological framework and permits the interaction of wake vortices with environments characterized by crosswind shear, stratification, humidity, and atmospheric turbulence. Results from the numerical simulations are being used to assist in the development of algorithms for an operational wake-vortex aircraft spacing system. A mesoscale weather forecast model is being adapted for providing operational forecast of winds, temperature, and turbulence parameters to be used in the terminal area. This paper describes the goals and modelling approach, as well as achievements obtained to date. Simulation results will be presented from the LES model for both two and three dimensions. The 2-D model is found to be generally valid for studying wake vortex transport, while the 3-D approach is necessary for realistic treatment of decay via interaction of wake vortices and atmospheric boundary layer turbulence. Meteorology is shown to have an important affect on vortex transport and decay. Presented are results showing that wake vortex transport is unaffected by uniform fog or rain, but wake vortex transport can be strongly affected by nonlinear vertical change in the ambient crosswind. Both simulation and observations show that atmospheric vortices decay from the outside with minimal expansion of the core. Vortex decay and the onset three-dimensional instabilities are found to be enhanced by the presence of ambient turbulence.
The effect of alloxan diabetes on the response of the adrenal gland to cold stress.

The existence of a functional relationship between the anterior pituitary, the pancreas and the adrenal cortex with respect to the control of carbohydrate metabolism is well established. The role of adrenal cortical hormones in the regulation of carbohydrate metabolism was pointed out by Britton and Silvette (1932). Long and Lukens (1936) demonstrated the improvement in diabetes which results from adrenalectomy and Ingle (1941) established the diabetogenic potency of pure cortical hormones. Although not all details of the mechanisms are known, participation of the adrenal cortex in the control of carbohydrate metabolism is unquestionable. Recently considerable attention has been given to the response of the adrenal cortex to various types of stress (Selye, 1937; Sayers and Sayers, 1948). Many types of environmental stress, drug or toxin administration or trauma will cause an increase in the activity of the adrenal cortex, associated with which hyperglycemia may be observed.
Statistics of polymer chains embedded on a diamond lattice. I. Exact results for the lattice version of the freely rotating chain

A polymer of finite length is embedded on a diamond lattice where the angle between adjacent monomers is cos−1(−1/3) = 109°. We show that the characteristic function Cn(k) can be calculated in closed form for an n link chain if all configurations (i.e., trans and gauche) are given equal weights. It is necessary to do a spherical average to get rid of the cubic symmetry artifically imposed by the diamond lattice. This represents the only model, other than the freely jointed chain, for which the characteristic function is known in closed form. This model may be regarded as the lattice version of the freely rotating chain. From the characteristic function we extract the first few moments 〈R2〉n, 〈R4〉n, and 〈R6〉n. We show that the results for the second and fourth moments are identical to those for the freely rotating chain, but the sixth moment is different. Various approximations to the probability distribution function Wn(R) [the Fourier transform of Cn(k)] are tested against the exact result.
Correlation between catalytic activity and support reducibility in the CO2 reforming of methane over Pt/CexZr1−xO2 catalysts

We have investigated the relationship between the reducibility of the support and the catalytic activity of supported Pt on a series of catalysts supported on ceria‐zirconia mixed oxides. The supports were prepared by co-precipitation with varying Ce/Zr ratios. X-ray diffraction analysis indicated that, depending on the Ce/Zr ratio, solid solutions of cubic Ce x Zr1 x O2 can be formed. The reducibility of the supports was determined by X-ray photoelectron spectroscopy (XPS). After reduction at 773 K in hydrogen the fraction of reduced cerium (i.e. Ce 3C ) was found to vary with the Ce content, exhibiting a maximum at a composition Ce0:5Zr0:5O2. A good correlation was found between the reducibility and the catalytic activity. It was found that the conversion of methane and CO2 obtained on the different catalysts after 22 h on stream went through a maximum as a function of Ce content in the support and that maximum occurred at the composition that exhibited the maximum reducibility. The H2/CO product ratio was also a function of the support composition, also presenting a maximum for the Pt/Ce0:5Zr0:5O2 catalyst. The amount and nature of carbonaceous deposits were investigated by combining temperature-programmed oxidation (TPO) studies with (XPS). The TPO profiles of all the spent samples revealed two oxidation peaks, one in the low-temperature region, 623‐723 K, and the other in the high-temperature region, 873‐973 K. The peak in the high-temperature region is dominant in the unpromoted catalysts, while the peak at low temperature is more prominent in the Pt/Cex Zr1 x O2 catalysts. XPS exhibits three types of carbon with different binding energies on the spent catalysts, two of them are two forms of coke, and the third one is due to carbonates. However, all of the peaks decreased after an oxidation at intermediate temperatures (i.e. 723 K). Therefore, it appears that the different peaks observed in TPO are not due to different forms of carbon, but rather to different locations on the catalyst surface. The amount of carbonates on the spent catalysts increased with the Ce content, but the correlation between carbonate concentration and activity was not as good as that between reducibility of the support and activity. © 2001 Elsevier Science B.V. All rights reserved.
Determinants of the streptococcal surface glycoprotein GspB that facilitate export by the accessory Sec system

GspB is a large cell-surface glycoprotein expressed by Streptococcus gordonii M99 that mediates binding of this organism to human platelets. This adhesin is glycosylated in the cytoplasm, and is then transported to the cell surface via an accessory Sec system. To assess the structural features of GspB that are needed for export, we examined the effects of altering the carbohydrate moieties or the polypeptide backbone of GspB. Truncated, glycosylated variants of GspB were exported exclusively via the accessory Sec pathway. When glycosylation was abolished, the GspB variants were still exported by this pathway, but minor amounts could also be transported by the canonical Sec system. GspB variants with in-frame insertions or deletions in the N-terminus were not secreted, indicating that this domain is necessary for export. However, the N-terminus is not sufficient for the transport of heterologous proteins, because C-terminal fusion of passenger proteins to this domain hindered export. In contrast, fusion of GspB to a canonical signal peptide resulted in the efficient export of non-glycosylated forms of the fusion protein via the canonical Sec pathway, whereas glycosylated forms could not be exported. Thus, the carbohydrate moieties and the atypical signal sequence of GspB interfere with export via the canonical pathway, and direct GspB towards the accessory Sec system.
Group based trajectories of network formation and dynamics

Abstract In this paper, we propose the application of a semi-parametric statistical methodology called Group-Based Developmental Trajectory Analysis to studying the dynamics of social networks. We begin with a discussion of theoretical problems in network analysis that may benefit from this approach. Next, we describe the methodology and how it can be applied to dyadic network data as well as aggregated node level data. We then demonstrate the methodology by analyzing the Newcomb Fraternity and the van de Bunt student data sets. Finally, we conclude with a discussion of potential directions for further research.
Macromolecular crowding induces polypeptide compaction and decreases folding cooperativity

A cell’s interior is comprised of macromolecules that can occupy up to 40% of its available volume. Such crowded environments can influence the stability of proteins and their rates of reaction. Using discrete molecular dynamics simulations, we investigate how both the size and number of neighboring crowding reagents affect the thermodynamic and folding properties of structurally diverse proteins. We find that crowding induces higher compaction of proteins. We also find that folding becomes less cooperative with the introduction of crowders into the system. The crowders may induce alternative non-native protein conformations, thus creating barriers for protein folding in highly crowded media.
Consequences of Quark Line (Okubo-Zweig-Iizuka) Rule

Consequences of the validity of the quark-line (Okubo-Zweig-Iizuka) rule have been studied both theoretically and experimentally. The present experimental data are consistent with the validity of the rule for ${1}^{\ensuremath{-}}$ and possibly ${2}^{+}$ nonets. With respect to the ${0}^{\ensuremath{-}}$ nonet, the rule is in reasonable agreement, if we consider a suitable mixing scheme for the $\ensuremath{\eta}\ensuremath{-}{\ensuremath{\eta}}^{\ensuremath{'}}$ complex. Theoretical implications of these facts are also discussed. The possible violation of the rule has been estimated to be 6% for the ${1}^{\ensuremath{-}}$ nonet and 15% for the ${0}^{\ensuremath{-}}$ nonet.
Selecting Weighting Schemes in Multivariate Generalizability Studies

This article examines the effects of different weighting schemes on selecting the optimal number of observations in multivariate-multifacet generalizability designs when cost constraints are imposed.
Food encounter rate of simulated termite tunnels in heterogeneous landscapes

The aim of this study was to explore how a heterogeneous landscape affects food encounter rate in the Formosan subterranean termite, Coptotermes formosanus Shiraki. To do this, a lattice model was formulated to simulate the tunneling structure of the termite. The model made use of minimized local rules derived from empirical data. In addition, a landscape structure was generated on a lattice space by using a neutral landscape model. Each lattice cell has a value h, representing spatially distributed property of the landscape (e.g., temperature or moisture). The heterogeneity of the landscape was characterized by a parameter, H controlling aggregation of lattice cells with higher values of h. Higher H values correspond to higher aggregation levels. The effect of the landscape heterogeneity on the encounter rate was clear in the presence of higher food density than in lower density. The effect was also enhanced by the increase of the number of primary tunnels.
Measurement of the differential Doppler shift

Doppler shifts between narrow-band signals observed at one or more pairs of receivers and originated from a remote source of radiation are useful for estimating source location and track. This paper deals with an instrumentationally attractive approach of estimating differential Doppler shifts by making center frequency measurements at each receiver output and subtracting them in a pairwise fashion. For low in-band signal-to-noise ratio conditions, center frequency measurements at different receiver outputs are weakly correlated. In this mode of operation, therefore, the mean-square error in the differential Doppler estimate equals the pairwise sum of the mean-square errors in each of the center frequency measurement. For high signal-to-noise ratio conditions, the various center frequency estimates are strongly correlated. In this mode of operation, the accuracy of the resulting differential Doppler estimate improves with the first power of the signal-to-noise ratio, even though the accuracy of each center frequency estimate approaches an absolute bound independent of the noise spectrum. The optimal (minimum mean-square error) differential Doppler shift estimate is obtained by simultaneous processing of the receiver outputs jointly. Comparison between the former (indirect) and the latter (direct) estimation techniques yields some interesting insights: the accuracy of the direct estimation procedure is proportional to T-3where T is the observation period. It is basically a coherent procedure. Center frequency measurement and the differential Doppler shift estimate derived from it are basically incoherent procedures and obey the well known T-1dependence. Under high signal-to-noise ratio conditions, the estimation error in both methods decreases with the first power of the signal-to-noise ratio. Under low signal-to-noise ratio conditions, the accuracy of the suboptimal indirect method is inferior to the optimal direct method by a factor proportional to the inverse first power of the individual signal-to-noise ratio.
Transportation of Ova and Zygotes Through the Genital Tract of Immature Mice Treated with Gonadotropins

Three hundred forty-six immature mice were superovulated with exogenous gonadotropins. Ninety-four females were not exposed to males and served as controls. Two hundred twenty-two females were exposed to known fertile males at the time of the ovulatory injection. Thirty additional females were cervically stimulated approximately 10 hr following the ovulatory injection. Varying numbers of females were killed on day(s) 1, 2, 3 and 4 following the ovulatory injection. Ova transport through the genital tract of immature females not exposed to males, as well as of females which were exposed to males but had not copulated, was accelerated. Zygotes, on the other hand, were not transported as rapidly through the genital tract as compared with ova transport in unmated females. It was noted, however, that zygotes entered the uteri approximately 24 hr earlier than would be expected in adult females of the same strain. These results suggested that the accelerated transport was the result of excessive amounts of endog...
A Commentary on the Use of Formative Measurement

The recent flurry of articles on formative measurement, particularly in the information systems literature, appears to be symptomatic of a much larger problem. Despite significant objections by met...
Radiation pattern of a test reflector antenna from near-field measurements over focal region of a coupled lens or offset reflector

A novel scheme has been investigated by which the radiation pattern of a test reflector antenna is determined by rescaling a plot of the electric field distribution in the focal plane of a large lens or in the offset focal plane of a large offset reflector placed in front of the transmitting antenna under test. The major advantage of the technique is that it permits a direct plot of the desired radiation pattern from near-field amplitude data without requiring any phase measurements. The test method is simpler and the test data more accurate than for pervious test methods. >
Legal status and source of offenders' firearms in states with the least stringent criteria for gun ownership

Background Gun possession by high-risk individuals presents a serious threat to public safety. U.S. federal law establishes minimum criteria for legal purchase and possession of firearms; many states have laws disqualifying additional categories for illegal possession. Methods We used data from a national survey of state prison inmates to calculate: 1) the proportion of offenders, incarcerated for crimes committed with firearms in 13 states with the least restrictive firearm purchase and possession laws, who would have been prohibited if their states had stricter gun laws; and 2) the source of gun acquisition for offenders who were and were not legally permitted to purchase and possess firearms. Results Nearly three of ten gun offenders (73 of 253 or 28.9%) were legal gun possessors but would have been prohibited from purchasing or possessing firearms when committing their most recent offense if their states had stricter prohibitions. Offenders who were already prohibited under current law acquired their gun from a licensed dealer, where a background check is required, five times less often than offenders who were not prohibited (3.9% vs. 19.9%; χ 2 =13.31; p≤0.001). Nearly all (96.1%) offenders who were legally prohibited, acquired their gun from a supplier not required to conduct a background check. Conclusions Stricter gun ownership laws would have made firearm possession illegal for many state prison inmates who used a gun to commit a crime. Requiring all gun sales to be subject to a background check would make it more difficult for these offenders to obtain guns.
Impact of gate direct tunneling current on circuit performance: a simulation study

The influence of gate direct tunneling current on ultrathin gate oxide MOS (1.1 nm/spl les/t/sub ox/spl les//1.5 nm, L/sub g/=50-70 nm) circuits has been studied based on detailed simulations. For the gate oxide thickness down to 1.1 nm, gate direct tunneling currents, including the edge direct tunneling (EDT), show only a minor impact on low V/sub dd/ static-logic circuits. However, dynamic logic and analog circuits are more significantly influenced by the off-state leakage current for oxide thickness below 1.5 nm, under low-voltage operation. Based on the study, the oxide thicknesses which ensure the International Technological Roadmap for Semiconductors (ITRS) gate leakage limit are outlined both for high-performance and low-power devices.
A mitochondrial topoisomerase IA essential for late theta structure resolution in African trypanosomes.

Summary Trypanosomes and Leishmania, protozoans that cause major human diseases, have a topologically intricate mitochondrial DNA (kinetoplast or kDNA) in the form of a network of thousands of interlocked circles. This unusual system provides a useful reporter for studying topoisomerase functions in vivo. We now find that these organisms have three type IA topoisomerases, one of which is phylogenetically distinctive and which we designate topoisomerase IAmt. In Trypanosoma brucei topoisomerase IAmt immunolocalizes within the mitochondrion close to the kDNA disk in patterns that vary with the cell cycle. When expression of TOPIAmt is silenced by RNAi there is a striking accumulation of kDNA late theta structure replication intermediates, with subsequent loss of kDNA networks and halt in cell growth. This essential enzyme provides clear molecular evidence for the obligatory role of a type IA enzyme in the resolution of late theta structures in vivo. With no close orthologue in humans it also offers a target for the rational development of selectively toxic new antiprotozoal therapies.
Pre- and Postdialysis Blood Pressures Are Imprecise Estimates of Interdialytic Ambulatory Blood Pressure

BP readings that are obtained in the dialysis unit are commonly used to make therapeutic decisions by clinicians and to predict morbidity and mortality by epidemiologists. Dialysis unit BP are also incorporated in the recent guidelines to target BP control. The magnitude of the difference, overestimation or underestimation, and agreement between dialysis unit BP and ambulatory BP (ABP) are unknown. Articles were selected from Medline to identify those that reported both ABP and dialysis unit BP in hemodialysis patients. Bias was calculated as the difference between dialysis unit and the corresponding ABP. Agreement limits between the BP measurement techniques were assessed by pooled SD of the difference using Bland-Altman methods. Predialysis systolic BP generally overestimated ABP by a variable amount. The heterogeneity between BP measurements did not allow for pooling of the estimates. The agreement limits between the two BP was 41.7 to -25.2 mmHg. Predialysis diastolic BP also generally overestimated the ABP with wide agreement limits (23.7 to -18.9 mmHg). In contrast, postdialysis BP underestimated average ABP with wide agreement limits for both postdialysis systolic BP (33.1 to -36.3 mmHg) and diastolic BP (19.3 to -23.9 mmHg). Dialysis unit BP measurements are imprecise estimates of ABP. Better methods are needed for the assessment of BP in hemodialysis patients for clinical decision making.
A Continuous-Time, Discrete-State Method for Simulating the Dynamics of Biochemical Systems

Computational systems biology is largely driven by mathematical modeling and simulation of biochemical networks, via continuous deterministic methods or discrete event stochastic methods. Although the deterministic methods are efficient in predicting the macroscopic behavior of a biochemical system, they are severely limited by their inability to represent the stochastic effects of random molecular fluctuations at lower concentration. In this work, we have presented a novel method for simulating biochemical networks based on a deterministic solution with a modification that permits the incorporation of stochastic effects. To demonstrate the feasibility of our approach, we have tested our method on three previously reported biochemical networks. The results, while staying true to their deterministic form, also reflect the stochastic effects of random fluctuations that are dominant as the system transitions into a lower concentration. This ability to adapt to a concentration gradient makes this method particularly attractive for systems biology-based applications.
Quiet Influences, Big Consequences: An Interview with Carol A. Pilgrim

Carol Pilgrim received her PhD from the University of Florida in 1987 with a specialization in the experimental analysis of behavior. She is currently Professor of Psychology and Associate Dean of the College of Arts and Sciences at the University of North Carolina—Wilmington. She has been honored with a Distinguished Teaching Professorship, the North Carolina Board of Governors Teaching Excellence Award, the Faculty Scholarship Award, the Chancellor's Teaching Excellence Award, and the College of Arts and Sciences Excellence in Teaching Award. Her research centers on both basic and applied behavior analysis, with an emphasis in human operant behavior, relational stimulus control, and the early detection of breast cancer. She has served as editor of The Behavior Analyst, associate editor of the Journal of the Experimental Analysis of Behavior and of The Behavior Analyst, co-editor of the Experimental Analysis of Human Behavior Bulletin, and as a member of the editorial boards of those and several other jo...
Online Phase Detection Algorithms

Today's virtual machines (VMs) dynamically optimize an application as it is executing, often employing optimizations that are specialized for the current execution profile. An online phase detector determines when an executing program is in a stable period of program execution (a phase) or is in transition. A VM using an online phase detector can apply specialized optimizations during a phase or reconsider optimization decisions between phases. Unfortunately, extant approaches to detecting phase behavior rely on either offline profiling, hardware support, or are targeted toward a particular optimization. In this work, we focus on the enabling technology of online phase detection. More specifically, we contribute (a) a novel framework for online phase detection, (b) multiple instantiations of the framework that produce novel online phase detection algorithms, (c) a novel client- and machine-independent baseline methodology for evaluating the accuracy of an online phase detector, (d) a metric to compare online detectors to this baseline, and (e) a detailed empirical evaluation, using Java applications, of the accuracy of the numerous phase detectors.
Brownian Dynamics Simulations of Polymer Mediated Capsid Assembly

Viral capsid assembly consists of hundreds to thousands of protein subunits spontaneously forming an icosahedral shell around the viral nucleic acid genome. We investigate this assembly using Brownian Dynamics simulations of coarse-grained models which include capsid protein cationic tails, or Arginine Rich Motifs (ARMs); a common structural element through which viral capsids interact with their nucleic acid genome or a surrogate polymer cargo. In our simulations, we find that the presence of a polymer greatly enhances the rate of assembly through a disordered mechanism, wherein many capsomers adhere to the polymer before successful capsid assembly occurs. Through these simulations we are able to investigate the role of several variables, including ARM location and length, as well as structural features of the polymer cargo, including the length, stiffness, and secondary structure (i.e. base pairing). Of particular interest, our results demonstrate that the amount and pattern of base pairing significantly alter the amount of polymer packaged within the capsid, providing a biologically relevant example of the relationship between cargo structure and capsid assembly.
A model worth considering

I'd like to introduce you to Scott Johnson, who thinks he has a better way of translating basic research discoveries into therapies for human diseases. Like many of the other people who have made a difference in the battle to cure diseases that pharmaceutical companies and governments have largely ignored - for example, the actor Michael J Fox in the case of Parkinson's disease and the financier Michael Milken in the case of prostate cancer - Mr Johnson has a very personal reason for wanting to see a particular disease cured. In 1976, when he was 20 years old, Scott Johnson was diagnosed with multiple sclerosis. He's 50 now, and he knows that, without a cure, his life expectancy is predicted to be about 7 years less than the average for a healthy adult. But that isn't the main reason that Scott Johnson is a man in a hurry. He's in a hurry because he thinks he's figured it out, and when you think you've figured it out, you're naturally anxious to see if you're right.
Contour extrapolation using probabilistic cue combination

A common approach to the problem of contour interpolation is based on the calculus of variations. The optimal interpolating contour is taken to be one that minimizes a given smoothness functional. Two important such functionals are total curvature (or bending energy) and variation in curvature. We analyzed contours extrapolated by human observers given arcs of Euler spirals that disappeared behind an occluding surface. Irrespective of whether the Euler spirals had increasing or decreasing curvature as they approached the occluding edge, visually-extrapolated contours were found to be characterized by decaying curvature. This curvature decay is modeled in terms of a Bayesian interaction between probabilistically-expressed constraints to minimize curvature and minimize variation in curvature. The analysis suggests that using fixed smoothness functionals is not appropriate for modeling human vision. Rather, the relative weights assigned to different probabilistic shape constraints may vary as a function of distance from the point(s) of occlusion. Implications are discussed for computational models of shape completion.
Narrowing the Distance: Implementing a Hybrid Learning Model for Information Security Education

Distance education has become an expectation with students who have grown up with technology as well as nontraditional and working students. Most universities now offer a wide range of online courses and degree programs to meet these needs. Online delivery of technology courses, however, has been problematic when the course includes very complex topics or hands-on components. An alternative presentation mode is the hybrid, or blended, model where class meetings alternate between physical face-to-face sessions and online activity component. This article discusses faculty preparation, as well as the benefits, challenges, and outcomes of using the hybrid model for a security course over a 2-year period.
Is health spending slowing down

Abstract: We analyze trends in real per capita health care spending. Using a different and, we believe, more appropriate adjustment for trends in general inflation than the Health Care Financing Ad...
Exploring the usability and effectiveness of interactive annotation and code review for the detection of security vulnerabilities

According to a recent IBM study, the average cost for a stolen record raised 9% to $145 in 2014 [1]. Since millions of credit card records are stolen every year, the cost can easily run into billions of dollars. Consequently, application security is a very important concern during the development of applications today. Resolving security problems later in the development process is very time consuming and expensive. Therefore, it is favorable to detect and resolve security vulnerabilities as soon as possible during the development process.
The Elusive Pragmatic Reasoning Schemas Effect

The present study examined the pragmatic reasoning schema theory of deductive reasoning—specifically, its explanation of performance on the selection task. Experiment 1 replicated a result crucial to the theory, the finding of facilitation on abstract versions of the selection task based on pragmatic reasoning schemas. However, Experiments 2, 3, and 4 established that this facilitation was dependent upon two presentation factors: (1) the presence of explicit negatives on the NOT P and NOT Q cards and (2) the inclusion of a checking context in the problem statement. These results are discussed in terms of Evans's two-stage (heuristic/analytic processing) model of reasoning.
Sensitive analysis of α-synuclein by nonlinear laser wave mixing coupled with capillary electrophoresis.

Multi-photon nonlinear laser wave-mixing spectroscopy is a novel absorption-based technique that offers excellent detection sensitivity for biomedical applications, including early diagnosis and investigation of neurodegenerative diseases. α-Synuclein is linked to Parkinson's disease (PD), and characterization of its oligomers and quantification of the protein may contribute to understanding PD. The laser wave-mixing signal has a quadratic dependence on analyte concentration, and hence the technique is effective in monitoring small changes in concentration within biofluids. A wide variety of labels can be employed for laser wave-mixing detection due to its ability to detect both chromophores and fluorophores. In this investigation, two fluorophores and a chromophore are studied and used as labels for the detection of α-synuclein. Wave-mixing detection limits of PD-related protein conjugated with fluorescein isothiocyanate, QSY 35 acetic acid, succinimidyl ester, and Chromeo P503 were determined to be 1.4 × 10(-13) M, 1.4 × 10(-10) M, and 1.9 × 10(-13) M, respectively. Based on the laser probe volume used, the corresponding mass detection limits were determined to be 1.1 × 10(-23) mol, 1.1 × 10(-20) mol, and 1.5 × 10(-23) mol. This study also presents molecular-based separation and quantification of α-synuclein by laser wave mixing coupled with capillary electrophoresis.
The Relation between Serum Insulin Levels and 8-Year Changes in Lipid, Lipoprotein, and Blood Pressure Levels

Hyperinsulinemia is associated with an adverse pattern of cardiovascular risk factors, including obesity, elevated triglyceride levels, low levels of high-density lipoprotein (HDL) cholesterol, and elevated blood pressure. Whether hyperinsulinemia precedes (and perhaps causes) this deterioration in the risk factors or merely accompanies the deterioration is controversial. We therefore examined the 8-year changes in lipids, lipoproteins, and blood pressure as a function of baseline levels of fasting insulin in 1,383 nondiabetic Mexican-American and non-Hispanic white subjects enrolled between October 1979 and November 1982 in the San Antonio Heart Study, a population-based longitudinal study of cardiovascular risk factors and diabetes in San Antonio, Texas. After age and concomitant changes in body mass index were adjusted for, fasting insulin at baseline was found to be correlated positively with 8-year changes in triglyceride levels and negatively with 8-year changes in HDL cholesterol levels (p less than 0.05). Among the non-Hispanic whites, insulin was more strongly correlated with a decline in HDL cholesterol levels in women than in men (p less than 0.001). Fasting insulin was also positively correlated with changes in both systolic and diastolic blood pressure in non-Hispanic whites, but not in Mexican Americans, although these correlations were slightly diminished and no longer achieved statistical significance after subjects receiving antihypertensive medications were excluded. These results support the hypothesis that in nondiabetic subjects, insulin has a direct regulatory effect on triglyceride and HDL cholesterol levels. These data provide evidence for a possible role for insulin in blood pressure regulation, at least in non-Hispanic whites, although further analysis of this issue is warranted.
Examining weight concern and delay discounting in adolescent females

Abstract Objective Pediatric obesity is a growing public health concern that contributes to high rates of negative long-term physical and mental health outcomes. Research focused on identifying risk for pediatric obesity has linked delay discounting, or an inclination for immediate rewards, as well as weight concern to individuals with greater Body Mass Index (BMI). The current study seeks to fill a void in the literature by examining how these two variables interact to promote higher BMI in female adolescents. Method Adolescent ( n = 60) females between the ages of 13–19 years ( m age = 17.45, SD = 1.74) of age completed the Eating Disorder Examination Questionnaire (EDE-Q) and the Delay Discounting Questionnaire. Results A mediation model examined whether delay discounting accounted for the relationship between weight concern and BMI. Results indicate that in the current study weight concern was negatively related to delay discounting and delay discounting was negatively related to BMI. The overall model revealed that a partial mediation occurred [b = 1.28, t(60) = 4.92, p Discussion These results suggest that while impulsivity is an important factor to consider, other constructs may also be influential in how weight concerns contribute to greater BMI. Nevertheless, the results indicate that prevention and interventions should identify females with high levels of both weight concern and impulsivity as an increased risk for experiencing pediatric obesity and long-term negative health outcomes.
In Situ Pulsed Laser Deposition of Nd 1.85 Ce 0.15 Cu0 4−y

We have deposited thin films of the electron-doped, high temperature superconductor Nd1.85Ce0.15CuO4-y by pulsed laser deposition. Films were deposited from a stoichiometric target using a KrF excimer laser (248 nm, 250 mJ/pulse, ∼2 J/cm2) as a function of substrate temperature, oxygen pressure and vacuum anneal conditions. The film composition and structure, as determined by RBS and XRD, were very sensitive to the deposition and subsequent anneal conditions. Stoichiometric films were deposited at low substrate temperatures (740 °C) but contained other orientations and phases. Predominantly c-axis oriented films were formed at high substrate temperatures (900 °C) and high background pressures of oxygen (200 mtorr). These films were semiconducting when quenched on oxygen or nitrogen following deposition. Slow cooling in a vacuum, yielded superconducting films with a maximum Tc-(onset) of 15 K and Tc(R=0) of 11 K. A variation of the deposition and anneal conditions indicated that loss of copper competed with the optimization of the carrier concentration.
Binding of the Bacillus sphaericus (Eubacteriales: Bacillaceae) toxin to midgut cells of mosquito (Diptera: Culicidae) larvae: relationship to host range.

Fluorescent-labelled Bacillus sphaericus (Neide) toxin was found to bind to sharply delineated regions of the proximal lobes of the gastric caecum and the posterior midgut of susceptible Culex quinquefasciatus Say larvae but did not bind to midgut cells of resistant Aedes aegypti (L.) and A. triseriatus (Say) larvae. Failure of this toxin to bind to midgut cells of certain mosquito species may be responsible for the restricted host range of B. sphaericus . The toxin appeared to enter the cells of C. quinquefasciatus larvae by receptor-mediated endocytosis, and it accumulated in the cells in bright fluorescent endocytic vesicles. Binding of fluorescent toxin to C. quinquefasciatus midgut cells and activity of the toxin to these larvae in bioassays was reduced by a lectin, wheat germ agglutinin. C. quinquefasciatus larvae ingested the toxin from clean water, and toxin passed through a column of kaolin in the larval gut to bind to midgut cells and intoxicate the larvae. A. aegypti larvae similarly ingested fluorescent-labelled toxin and other proteins from clean water. These results indicate that these larvae drink the surrounding medium.
Electrochemistry of aqueous pyridinium: exploration of a key aspect of electrocatalytic reduction of CO2 to methanol.

The mechanism by which pyridinium (pyrH+) is reduced at a Pt electrode is a matter of recent controversy. The quasireversible cyclic voltammetric wave observed at −0.58 V vs SCE at a Pt electrode was originally proposed to correspond to reduction of pyrH+ to pyridinyl radical (pyrH•). This mechanistic explanation for the observed electrochemistry seems unlikely in light of recent quantum mechanical calculations that predict a very negative reduction potential (−1.37 V vs SCE) for the formation of pyrH•. Several other mechanisms have been proposed to account for the discrepancy in calculated and observed reduction potentials, including surface adsorption of pyrH•, reduction of pyrH+ by two electrons rather than one, and reduction of the pyrH+ proton to a surface hydride rather than a π-based radical product. This final mechanism, which can be described as inner-sphere reduction of pyrH+ to form a surface hydride, is consistent with experimental observations.
Further evidence for charge transfer complexes in brown carbon aerosols from excitation-emission matrix fluorescence spectroscopy.

The light-absorbing fraction of organic molecules in ambient aerosols, known as “brown carbon,” is an important yet poorly characterized component. Despite the fact that brown carbon could alter the radiative forcing of aerosols significantly, identification of specific chromophores has remained challenging. We recently demonstrated that charge transfer (CT) complexes formed in organic molecules could be responsible for a large fraction of absorption observed in water-extracted ambient particulate matter.1 In the present study, we use excitation–emission matrix fluorescence spectroscopy to further corroborate the importance of CT complexes in defining aerosol optical properties. Monotonically increasing and decreasing quantum yields, decreasing Stokes shifts, and red-shifting emission maxima are observed from ambient particulate matter collected in Athens, Georgia, strongly suggesting that a superposition of independent chromophores is not sufficient to explain brown carbon absorption and fluorescence. In...
New Insights into the Biosynthesis of Fosfazinomycin.

The biosynthetic origin of a unique hydrazide moiety in the phosphonate natural product fosfazinomycin is unknown. This study presents the activities of five proteins encoded in its gene cluster. The flavin-dependent oxygenase FzmM catalyses the oxidation of L-Asp to N-hydroxy-Asp. When FzmL is added, fumarate is produced in addition to nitrous acid. The adenylosuccinate lyase homolog FzmR eliminates acetylhydrazine from N-acetyl-hydrazinosuccinate, which in turn is the product of FzmQ-catalysed acetylation of hydrazinosuccinate. Collectively, these findings suggest a path to N-acetylhydrazine from L-Asp. The incorporation of nitrogen from L-Asp into fosfazinomycin was confirmed by isotope labelling studies. Installation of the N-terminal Val of fosfazinomycin is catalysed by FzmI in a Val-tRNA dependent process.
Ingredient migration and their effect on NEPE propellant bonding system

According to the change of bond strength,ingredient migration and their effect in NEPE propellant bonding system were studied by HPLC and ICP.The results show that the migration quantity of nitric ester and stabilizer in HTPB/TDI liner is rising with the increase of the content of urethane hard segment.The migration of nitric ester has no obvious disadvantageous effect on liner storage bond property,but it makes the storage mechanical property of HTPB/TDI liner decrease markedly.The unilateral migration of TPB in NEPE propellant makes the bond property decrease.The unilateral migration of stabilizer in NEPE propellant makes the storage bond property decrease obviously.
Instrumentation of the occipital-atlantal-axial (c0-c1-c2) complex.

Few areas of spinal surgery present a greater challenge than management of occipitocervical abnormalities. This is due to the simultaneous presence of two commanding, yet conflicting treatment principles. First, decompression and protection of the spinal cord at this level is synonymous with the presevation of life itself. Second, however, the degree of cervical movements at this junction is unprecedented in the spine, requiring the preservation movement yet stabilization of discrete motion segemnts. The interrelation of these two critical functions is realized in the complex arrangement of the C0- C1-C2 anatomic configuration. The occipitocervical junction is responsible for 50% of the 90 degrees of head rotation. In addition, 10-15 degrees of flexion and extension are added to the subaxial cervical spine by C0-C1-C2.This duality of function is the primary reasin for the complexity of the facet joints in this location. No lateral bending occurs at this level.
First test of a species-selective adult sea lamprey migration barrier

Abstract A species-specific, non-chemical method of preventing adult sea lamprey ( Petromyzon marinus ) passage into Great Lakes tributary streams is necessary to help reduce the population of this invasive fish species and prevent fragmentation of habitat of native fish species. We tested the effectiveness of a barrier in the form of a short angled (10° and 20°) wetted ramp in a lab and field setting. At the steeper angle, none of the ten adult sea lampreys tested achieved passage, although numerous attempts were observed. On the shallower ramp, 15–20% (3–4/20) of tested individual lampreys passed. We tested sample groups of nine native fish species and found varying rates of attempted and successful passage among these groups. More species and individuals succeeded in passing the 10° ramp. At least one individual from each of six species was able to pass the barrier: common sucker ( Catostomus commersonii ), hognose sucker ( Hypentelium nigricans ), creek chub ( Semotilus atromaculatus ), green sunfish ( Lepomis cyanellus ), smallmouth bass ( Micropterus dolomieu ), and golden shiner ( Notemigonus crysoleucas ). Only two of the individual walleyes ( Sander vitreus ) swam high enough to fully emerge from the downstream pool, with no successful passage. Although our sample sizes are not large enough to infer effectiveness of the selective ramp barrier at a species level, we conclude that inclined wetted ramps merit further investigation as a possible selective sea lamprey barrier.