cssi/SciSciGPT-SciSciNet huggingface dataset:
Petrov type, principal null directions, and Killing tensors of slowly rotating black holes in quadratic gravity

The ability to test general relativity in extreme gravity regimes using gravitational wave observations from current ground-based or future space-based detectors motivates the mathematical study of the symmetries of black holes in modified theories of gravity. In this paper we focus on spinning black hole solutions in two quadratic gravity theories: dynamical Chern-Simons and scalar Gauss-Bonnet gravity. We compute the principal null directions, Weyl scalars, and complex null tetrad in the small-coupling, slow rotation approximation for both theories, confirming that both spacetimes are Petrov type I. Additionally, we solve the Killing equation through rank 6 in dynamical Chern-Simons gravity and rank 2 in scalar Gauss-Bonnet gravity, showing that there is no nontrivial Killing tensor through those ranks for each theory. We therefore conjecture that the still-unknown, exact, quadratic-gravity, black-hole solutions do not possess a fourth constant of motion.
Revisiting African Agriculture: Institutional Change and Productivity Growth

Building on a recent analysis of total factor productivity growth in African agriculture, this paper revisits the political economy underpinnings of policies affecting agriculture. We examine the effect of institutional change on the productivity performance of African agriculture. Our central finding is that institutional change in the form of competitive presidential elections has played an important role in driving a resurgence of productivity growth. The emergence of electoral competition in Africa changed policymakers’ incentives, resulting in both sectoral and macroeconomic policy reforms favorable to agriculture, following decade of policy discrimination against agriculture. These reforms, to varying degrees, contributed to an acceleration of productivity growth in African agriculture.
Exploring L2 learners' Task-related Identities in a Reading Circle Task Through Conversation Analysis

Using conversation analysis as the research approach, this study explores how L2 learners utilize their task-related identities during task interactions and how those identities are used as resources for task management. Eight students in an ESL academic reading class formed two groups while they did their reading circle task for six rounds. In each round, the students took turns to be in charge of a specific role in the discussion session (i.e., discussion leader, notetaker, vocabulary definer, and contextualizer). Data was collected from all rounds and analyzed for emerging patterns. Results showed that (a) the participants used each other’s assigned identities skillfully to orient the group to the institutional goal, and (b) the participants used their own existing obligations to problematize the task interactions. By providing insights on those dynamic task-related identities, this study broadens our understanding of interactions happening at the task implementation stage and suggests pedagogical implications.
Thiol oxidation and reduction in major histocompatibility complex class I-restricted antigen processing and presentation.

Publisher Summary This chapter presents a general method for the identification of glycoproteins interacting with ERp57 and its application to the study of the major histocompatibility complex (MHC) class I loading complex. MHC class I molecules deliver endogenous peptides to the cell surface for inspection by the immune system. Assembly of class I peptide complexes takes place in the oxidizing environment of the endoplasmic reticulum (ER) and involves the formation of disulfide bonds in the MHC class I molecule. The class I assembly machinery includes the thiol-dependent oxidoreductase ERp57. This molecule is a member of the protein disulfide isomerase (PDI) family and contains two distinct thioredoxin (TR) motifs. ERp57 is known to be specifically recruited to nascent glycoproteins by either calreticulin (CRT) or calnexin (CNX). Its capability to mediate disulfide bond rearrangements in glycoproteins has been demonstrated in vitro and in vivo and is outlined in the chapter.
Abstract P229: Pericardial Fat Density is Associated With Insulin Resistance in Treated HIV Infection: The SATURN-HIV Trial

Objective: To examine associations of pericardial fat (PCF) volume and density with baseline and changes in insulin resistance among HIV+ subjects participating in a trial of statin therapy. Methods: SATURN-HIV was a 96-week double-blind, randomized trial of 10 mg daily rosuvastatin versus placebo among 147 HIV+ subjects on stable antiretroviral therapy with LDL-c ≤130mg/dL and evidence of heightened T-cell activation or increased inflammation (high sensitivity C-reactive protein ≥2mg/L). PCF volume (ml) and density (mean Hounsfield Units) were measured from coronary calcium CT scans at entry. Homeostatic model of insulin resistance (HOMA-IR) was calculated from insulin and glucose at entry, 24, 48, and 96 weeks. Pearson correlations and linear mixed modeling were used to explore relationships between PCF and insulin resistance. Results: Median (Q1, Q3) age was 46 (40, 53) years; 78% were male and 68% African American; 49% were on a protease inhibitor. Median HOMA-IR was 1.84 (1.06, 3.33) at baseline, and participants randomized to statin had larger 0-96 week mean percentage increase in HOMA-IR (+73% vs +33%, statin vs placebo, p=0.009). PCF density did not correlate with measures of total body adiposity (BMI r=0.057 and total body fat r=-0.034, both p>0.4), but was negatively correlated to waist-hip ratio (-0.337, p Conclusions: Coronary calcium scans are widely used to assess cardiovascular risk and appropriateness of statin therapy. In this HIV+ population, PCF density, a simple measure obtained from these scans, appears to be a novel marker of insulin resistance that is independent of PCF volume. Larger, adequately powered studies are needed to determine if PCF density predicts development of insulin resistance on statin.
A Kinetic Study of the Complementation of Fragments of Staphylococcal Nuclease

Abstract The complementation of fragments of staphylococcal nuclease to form an ordered structure was studied by stopped flow kinetic measurements. The increase in the intensity of tryptophan fluorescence of residue 140 on complementation was followed. The complementation of two fragments containing residues 6 to 48 and residues 49 to 149 (or 50 to 149) to form Nuclease-T' follows apparent first order kinetics, both with regard to variation of time and fragment concentration accessible to study. The first order rate constant of the formation of Nuclease-T' is in the range of 0.03 to 0.05 s-1, which is much less than that of refolding of acid-denatured intact nuclease observed by Schechter et al. (Schechter, A. N., Chen, R.F., and Anfinsen, C.B. (1970) Science 167, 886–887). The change of temperature from 5° to 45° caused only a small increase in the rate of formation of Nuclease-T'. The presence of the ligands, thymidine 3',5'-diphosphate and Ca2+, and the change of pH of the reaction mixture from 5 to 8 had no effect on the rate constant. The complementation between the fragments of residues 1 to 126 and of residues 99 to 149 and between the fragments of residues 1 to 126 and of residues 49 to 149 (or 50 to 149) also fits first order kinetics and shows rate constants equivalent to that of Nuclease-T'. Examination of the kinetic equation for the simplest model, in which specific prefolding of each fragment is required for the productive collision, and the collision is the rate-limiting step of the complementation, fails to explain these results. However, the results may be interpreted by assuming the rate-limiting step either to be the prefolding of one of the two fragments, which then combines with the other fragment, or the folding of a disordered intermediate complex formed by the two fragments.
Factor-Join: A Unique Approach to Compiling Array Languages for Parallel Machines

This paper describes a new approach to compiling and optimizing array languages for parallel machines. This approach first decomposes →ray language operations into factors, where each factor corresponds to a different communication or computation structure. Optimizations are then achieved by combining, or joining, these factors. Because factors preserve high level information about array operations, the analysis necessary to perform these join operations is simpler than that required for scalar programs. In particular, we show how data parallel programs written in the ZPL programming language are compiled and optimized using the factor-join approach, and we show that a small number of factors are sufficient to represent ZPL programs.
SU-E-J-13: Six Degree of Freedom Image Fusion Accuracy for Cranial Target Localization On the Varian Edge Stereotactic Radiosurgery System: Comparison Between 2D/3D and KV CBCT Image Registration

Purpose: To determine the 6 degree of freedom systematic deviations between 2D/3D and CBCT image registration with various imaging setups and fusion algorithms on the Varian Edge Linac. Methods: An anthropomorphic head phantom with radio opaque targets embedded was scanned with CT slice thicknesses of 0.8, 1, 2, and 3mm. The 6 DOF systematic errors were assessed by comparing 2D/3D (kV/MV with CT) with 3D/3D (CBCT with CT) image registrations with different offset positions, similarity measures, image filters, and CBCT slice thicknesses (1 and 2 mm). The 2D/3D registration accuracy of 51 fractions for 26 cranial SRS patients was also evaluated by analyzing 2D/3D pre-treatment verification taken after 3D/3D image registrations. Results: The systematic deviations of 2D/3D image registration using kV- kV, MV-kV and MV-MV image pairs were within ±0.3mm and ±0.3° for translations and rotations with 95% confidence interval (CI) for a reference CT with 0.8 mm slice thickness. No significant difference (P>0.05) on target localization was observed between 0.8mm, 1mm, and 2mm CT slice thicknesses with CBCT slice thicknesses of 1mm and 2mm. With 3mm CT slice thickness, both 2D/3D and 3D/3D registrations performed less accurately in longitudinal direction than thinner CT slice thickness (0.60±0.12mm and 0.63±0.07mm off, respectively). Using content filter and using similarity measure of pattern intensity instead of mutual information, improved the 2D/3D registration accuracy significantly (P=0.02 and P=0.01, respectively). For the patient study, means and standard deviations of residual errors were 0.09±0.32mm, −0.22±0.51mm and −0.07±0.32mm in VRT, LNG and LAT directions, respectively, and 0.12°±0.46°, −0.12°±0.39° and 0.06°±0.28° in RTN, PITCH, and ROLL directions, respectively. 95% CI of translational and rotational deviations were comparable to those in phantom study. Conclusion: 2D/3D image registration provided on the Varian Edge radiosurgery, 6 DOF-based system provides accurate target positioning for frameless image-guided cranial stereotactic radiosurgery.
Conceptual modeling with the object-process methodology in software architecture

The ultimate goal of software design is to transform real world problems into software solutions. Architectural design is the earliest phase of this process. It is a phase in which conceptual modeling plays an important role. In conceptual modeling, designers pay more attention to accurately describing real world problems than making detailed design decisions. Object-Oriented Analysis and Design is the prevailing software development methodology. Using object-orientation for conceptual modeling is often difficult, especially because of the encapsulation of processes within objects. An alternative approach is the Object-Process Methodology (OPM). OPM is a systems engineering approach that, while recognizing the duality of objects and processes, establishes a peer relationship among them. This peer relationship enables conceptual modelers to describe real world problems more naturally. Using OPM and its support tool, designers can develop integrated conceptual models that faithfully capture the characteristics and interactions of real-world entities. This paper briefly introduces OPM and its support tools and uses case studies to show the advantages of OPM for conceptual modeling in software architecture design.
Examination of design strategies for inverter-driven induction machines

Considerations for the design of inverter-driven induction machines are presented. Decades of innovation and evolution within the realm of fixed frequency and voltage excitation has allowed the induction machine to become a mature and widely used electromechanical system. Well-defined and accepted performance criteria for conventional line-fed induction machines are used to adequately reduce the machine design space to manageable proportions. Due to the altered operational conditions that exist for inverter-driven systems with power electronics-based converters, generalized constraining conditions are not so well defined, and thus the design space has not been clearly determined. This work explores many of the geometrical design variables and conventions that are commonly employed, the motivation behind their existence, and how/if they are affected by the introduction of high-fidelity power electronics-based machine excitations. An electric traction system requiring a broad constant-power region is used to establish how application-specific constraints heavily determine overall design objectives, allowing for design flexibility in slot count, skewing, and rotor bar geometries to be noted.
Some estimators and tests for accelerated hazards model using weighted cumulative hazard difference

For a censored two-sample problem, Chen and Wang [Y.Q. Chen and M.-C. Wang, Analysis of accelerated hazards models, J. Am. Statist. Assoc. 95 (2000), pp. 608–618] introduced the accelerated hazards model. The scale-change parameter in this model characterizes the association of two groups. However, its estimator involves the unknown density in the asymptotic variance. Thus, to make an inference on the parameter, numerically intensive methods are needed. The goal of this article is to propose a simple estimation method in which estimators are asymptotically normal with a density-free asymptotic variance. Some lack-of-fit tests are also obtained from this. These tests are related to Gill–Schumacher type tests [R.D. Gill and M. Schumacher, A simple test of the proportional hazards assumption, Biometrika 74 (1987), pp. 289–300] in which the estimating functions are evaluated at two different weight functions yielding two estimators that are close to each other. Numerical studies show that for some weight func...
Flavor changing effects in theories with a heavy Z ′ boson with family nonuniversal couplings

There are theoretical and phenomenological motivations that there may exist additional heavy ${Z}^{\ensuremath{'}}$ bosons with family nonuniversal couplings. Flavor mixing in the quark and lepton sectors will then lead to flavor changing couplings of the heavy ${Z}^{\ensuremath{'}},$ and also of the ordinary Z when ${Z\ensuremath{-}Z}^{\ensuremath{'}}$ mixing is included. The general formalism of such effects is described, and applications are made to a variety of flavor changing and CP-violating tree and loop processes. Results are described for three specific cases motivated by a specific heterotic string model and by phenomenological considerations, including cases in which all three families have different couplings, and those in which the first two families, but not the third, have the same couplings. Even within a specific theory the results are model dependent because of unknown quark and lepton mixing matrices. However, assuming that typical mixings are comparable to the Cabibbo-Kobayashi-Maskawa matrix, processes such as coherent \ensuremath{\mu}-e conversion in a muonic atom, ${K}^{0}\ensuremath{-}{K}^{0}$ and $B\ensuremath{-}\overline{B}$ mixing, \ensuremath{\epsilon}, and ${\ensuremath{\epsilon}}^{\ensuremath{'}}/\ensuremath{\epsilon}$ lead to significant constraints on ${Z}^{\ensuremath{'}}$ bosons in the theoretically and phenomenologically motivated range ${M}_{{Z}^{\ensuremath{'}}}\ensuremath{\sim}1\mathrm{TeV}.$
Sensitive absorption spectroscopy using tunable semiconductor lasers

As performance levels for sophisticated electronic materials and device processing increase so to does the demand for versatile methods for on-line real time sensing of many process parameters. To that end we have developed a series of tunable semiconductor laser spectrometers for use in detection schemes of gas phase chemical species via infrared absorption spectroscopy. We report here on characterization of dual modulation schemes for enhanced sensitivity, interference fringe free, absorption spectroscopy data.
Saccades induced electrically from the dorsomedial frontal cortex: evidence for a head-centered representation

The amplitude and direction of saccadic eye movements evoked electrically from the dorsomedial frontal cortex (DMFC) of monkeys vary with starting eye position. This observation has been used to argue that the DMFC codes saccadic eye movements in head-centered coordinates. Whether the amplitude and direction of the evoked saccades are also affected by changes in head position has never been demonstrated. Such a result would argue against a head-centered representation, and instead would suggest a representation anchored to another body part. Tests were conducted on rhesus monkeys to determine whether changing the position of the head with respect to the trunk or changing the position of the head with respect to the gravitational axis alters saccadic parameters. The amplitude and direction of saccadic eye movements remained invariant to such manipulations. These findings confirm the claim that the DMFC encodes saccadic eye movements in head-centered coordinates.
Antecedents and Consequences of Salesperson Identification with the Brand and the Company

One important area of research in branding has focused on consumers’ identification with their favorite brands, antecedents of this identification, and the potential positive implications from such identification (Fournier 1995). This research suggests that individuals will adopt certain behaviors when they associate/identify themselves with satisfying self-defining relationships or self-concepts. However, to date little research has investigated whether similar relationships may hold when salespeople identify with the brand they represent. One question of particular interest is how the salesperson connects with the brand. Salespeople work independently to establish credibility and reputation with the buyers, while marketing works to establish a brand identity for the firm’s products. Yet we know very little about how these two market influences interact with one another. Only recently has this topic been addressed as the subject of research by Hughes and Ahearne (2010). The purpose of this paper is to improve our understanding of salesperson identification with the brand and the company they represent, how it fits with the salesperson’s own identity, and to examine some of the antecedents to and consequences from salesperson identification.
Characterization of HIV incubation distributions and some comparative studies

In this paper we use a general stochastic model to characterize the HIV incubation distributions. We generate some Monte Carlo data under different conditions and compare the fitting of HIV incubation distributions by some well known parametric models and some non-parametric methods. The parametric models include most of those that have appeared in the literature. The non-parametric methods include the Kaplan--Meier method, the EMS method, the spline approximation and the Bacchetti method. The comparison criteria are the chi-square statistic, the residual sum of squares, the AIC and the BIC. We show that the non-parametric methods, especially the EMS method, provide excellent fits in almost all cases; for the parametric models, the generalized log-logistic distributions with three and with four parameters fit better than other parametric models.
Quantitative study of the islets of langerhans of the beagle as a function of age

Abstract The volume of the islets of Langerhans of the beagle was studied as a function of age and body weight. A statistically significant correlation was found between the total islet volume/total pancreatic volume vs. age for the beagle from birth to the weaning age of 8 weeks. A statistically significant difference was observed between the curvilinear regressions of the males and females in this age group. No statistically significant correlation were found in the beagles older than 8 weeks with regard to the total islet volume/total pancreatic volume vs. age, with or without taking into account body weight. A statistically significant correlation was observed between the average volume of an islet and the body weight of the beagle, independent of age. The physiologic implications of these findings are considered briefly.
Evaluation of viral and mammalian promoters for driving transgene expression in mouse liver

Fifteen luciferase plasmid constructs driven by various promoters including cytomegalovirus (CMV), Rous sarcoma virus (RSV), human serum albumin (SA), {alpha}-1 antitrypsin (AAT), cytochrome P450 CYP1A2, CYP2C9, CYP2C18, CYP2D6, CYP3A4, mouse CYP2b10, human amyloid precursor protein (APP), chicken {beta} actin (ACT), nuclear factor {kappa} B (NF{kappa}B), and heat shock protein 70 (HS) promoters were hydrodynamically introduced into mouse hepatocytes, and the level and persistence of luciferase gene expression were examined. Eight hours post-gene transfer, the CMV and AAT promoters showed the highest activity, followed by the CYP2D6, HS, and RSV promoters which were slightly less active. The human serum albumin promoter exhibited the lowest activity among the promoters examined. The time course of gene expression showed a two-phase decline in luciferase activity with a rapid phase within First 5-7 days and a slower decline thereafter. Results from Southern and Northern blot analyses revealed a good correlation between the decline of luciferase activity and the decrease in mRNA level, suggesting promoter silencing as the possible mechanism for the observed transient luciferase gene expression. Inclusion of EBN1 and oriP sequences of Epstein-Barr virus into the plasmid extended the period of active transcription for about one week. These results provide important information concerning themore » role of promoters in regulating transgene expression and for the proper design of plasmids for gene expression and gene therapy.« less
Teaching students to design secure systems

The pedagogy used to teach computer security to students new to the field is usually handled by a one- or two-course augmentation to an existing curriculum. Furthermore, the courses tend to be technology-centric and often do not uncover the underlying processes that students can transfer to new situations. In this article, we look more closely at determining an appropriate scope and sequence for information assurance (IA) and briefly describe a project whose goal is the articulation of an IA curriculum.
XIA: architecting a more trustworthy and evolvable internet

Motivated by limitations in today's host-centric IP network, recent studies have proposed clean-slate network architectures centered around alternate first-class principals, such as content, services, or users. However, muchlike the host-centric IP design, elevating one principal type above others hinders communication between other principals and inhibits the network's capability to evolve. This paper presents the eXpressive Internet Architecture (XIA), an architecture with native support for multiple principals and the ability to evolve its functionality to accommodate new, as yet unforeseen, principals over time. We present the results of our ongoing research motivated by and building on the XIA architecture, ranging from topics at the physical level (``how fast can XIA go'') up through to the user level.
Inhibition of rat brain monoamine oxidase by formamidines and related compounds

Abstract The efficacy of the pesticide chlordimeform or N ′-(4-chloro- o -tolyl)- N , N ′-dimethylform-amidine, six chlordimeform metabolites, and eleven related compounds as inhibitors of the oxidative deamination of radiocarbon-labelled biogenic amines by rat brain monoamine oxidase was examined. The I 50 value for chlordimeform with tyramine as substrate was 6.0 × 10 −5 M. Inhibition following prolonged pre-incubation of chlordimeform with monoamine oxidase increased with time. and this was attributed, at least in part, to the formation of the more potent monoamine oxidase inhibitor 4′-chloro- o -formotoluidide, a known chlordimeform metabolite and degradation product. 4′-Chloro- o -formotoluidide was the most potent monoamine oxidase inhibitor examined yielding I 50 values of 2.6 × 10 −6 m. 1.5 × 10 −6 M and 3.2 × 10 −6 M, with tyramine, dopamine, and serotonin, respectively, as substrates. The N -demethyl (demethylchlordimeform) and N -didemethyl chlordimeform metabolites gave I 50 values with tyramine of 3.3 × 10 −5 M and 7.5 × 10 −5 M, respectively. Three additional metabolites, 4-chloro- o -toluidine, 5-chloroanthranilic acid, and N -formyl-5-chloroanthranilic acid, were weak inhibitors with I 50 values of 1 × 10 −4 m or higher. The other formamidine compounds also inhibited the oxidative deamination of tyramine; I 50 values ranged from 9.3 × 10 −5 m to 7.5 × 10 −6 m. Lineweaver-Burk plots revealed that chlordimeform, demethylchlordimeform, and 4′-chloro- o -formotoluidide were competitive inhibitors of the oxidative deamination of β-phenylethylamine, tyramine, dopamine, tryptamine, and serotonin. Inhibition was reversible since activity was restored by washing.
Synaptotagmin II expression partially rescues the growth defect of the yeast sec15 secretory mutant

Abstract Synaptotagmins are a family of calcium- and phospholipid-binding proteins implicated in the function of cell exocytosis. Synaptotagmins I and II are neurally expressed proteins thought to be involved in neurotransmitter release from neurons. We have expressed rat synaptotagmin II in several Saccharomyces cerevisiae temperature-sensitive secretory mutants that are defective in Golgi to plasma membrane vesicular transport. Synaptotagmin II expression was able to partially rescue the growth defect in one particular mutant, sec15 . No suppression was observed when synaptotagmin II was expressed in sec1, sec2, sec4, sec5, sec6, sec8, sec9, sec14, sec17 , or sec18 . Two synaptotagmin II deletion mutants were also expressed in sec15 and screened for suppression. The expression of the cytoplasmic domain of synaptotagmin alone was not able to suppress the sec15 growth defect. In addition, the expression of a synaptotagmin II fragment lacking the second half of the cytoplasmic domain including the second C2 domain did not suppress sec15 . We have isolated a membrane fraction enriched in post-Golgi vesicles from a sec15 strain expressing synaptotagmin II and found that synaptotagmin II co-purifies with this fraction, suggesting that the rat synaptotagmin II is targeted to membranes in yeast. Sec 15p forms a large multisubunit protein complex that includes Sec6p and Sec8p. This protein complex is thought to function in a late stage of exocytosis in yeast. Sec6p and Sec8p homologs have been identified in mammalian cells. Our studies suggest that synaptotagmin may be a part of this complex or regulate its function in mammalian cells.
Improved sea ice shortwave radiation physics in CCSM4: The impact of melt ponds and aerosols on Arctic Sea ice

AbstractThe Community Climate System Model, version 4 has revisions across all components. For sea ice, the most notable improvements are the incorporation of a new shortwave radiative transfer scheme and the capabilities that this enables. This scheme uses inherent optical properties to define scattering and absorption characteristics of snow, ice, and included shortwave absorbers and explicitly allows for melt ponds and aerosols. The deposition and cycling of aerosols in sea ice is now included, and a new parameterization derives ponded water from the surface meltwater flux. Taken together, this provides a more sophisticated, accurate, and complete treatment of sea ice radiative transfer. In preindustrial CO2 simulations, the radiative impact of ponds and aerosols on Arctic sea ice is 1.1 W m−2 annually, with aerosols accounting for up to 8 W m−2 of enhanced June shortwave absorption in the Barents and Kara Seas and with ponds accounting for over 10 W m−2 in shelf regions in July. In double CO2 (2XCO2) ...
Credit to government and banking sector performance.

Abstract The impact of credit to government on three aspects of banking sector performance – its deepening over time, profitability, and efficiency – is examined for 142 countries. Country regressions suggest a sizeable negative effect of credit to government on bank deepening in developing countries, but no impact in advanced economies. Bank regressions find that credit to government raises the profitability but reduces the efficiency of banks in developing countries; in advanced economies, there appears to be no impact on profitability but a positive one on efficiency.
Actinomyces viscosus Colonization of Mouse Teeth

The implantation of Actinomyces viscosus strain T14V-J1 was studied in mice in vivo. The optimum age range for implantation was from 40 to 80 days. The minimum infective dose of strain T14V-J1 required for colonization in all inoculated animals (ID100) was 5 x 108CFU for 40-day-old mice and 1 x 109 CFU for 100-day-old mice. The high ID100 reguired for implantation of strain T14V-J1 in these mice is consistent with the finding that tooth surfaces of these animals are not colonized by detectable indigenous Actinomyces. The infection could also be transmitted to non-infected mice housed with infected mice. This in vivo model can be used to evaluate the potential for reducing or preventing Actinomyces colonization on teeth by vaccination with fimbrial adhesins.
An application of mean-field perturbation theory for the adsorption of polar molecules in nanoslit-pores

In the present research study, we present the development of a model for characterizing and predicting the adsorption of polar molecules between two parallel plates based on mean-field perturbation theory. The electrostatic forces between fluid–fluid molecules in the slit shaped pore are modeled by considering permanent dipole–dipole interactions and permanent dipole-induced dipole moment interactions. The intermolecular potential for the electrostatic interactions was obtained by considering statistical averages over all possible orientations of the molecules. The proposed model is then used to study the sorption of water molecules in the slit shaped pore and an explicit equation for the Helmholtz free energy of the pore phase fluid is derived. Adsorption isotherms for different pore sizes are simulated and the relative contributions of fluid–wall and fluid–fluid interactions to the Helmholtz free energy are calculated as an illustration and compared with the results of existing models in the literature.
A Technique for Estimating Tropical Open-Ocean Rainfall from Satellite Observations

Abstract A procedure has been devised for extracting the frequency of highly reflective clouds from visual satellite picture mosaics of the tropical Pacific Ocean. Over the period May 1971 through April 1973 monthly frequencies of highly reflective clouds were statistically tested for a regression relationship with 820 station-months of coral island rainfall. The correlation coefficient was +0.75 while the line of regression passed near the origin and was equidistant from the abscissa and ordinate. The F calculated from an analysis of variance table was highly significant at the 1% level. The rainfall estimated from highly reflective cloud frequencies was then compared to other tropical Pacific Ocean climatological rainfall estimates.
Understanding the perceived determinants of weight-related behaviors in late adolescence: a qualitative analysis among college youth.

Objective: Identify key factors underlying college weight gain, nutrition, and physical activity. Design: Six focus groups and one-on-one interviews. Setting: Large, public Midwestern university. Participants: Fifty full-time freshman and sophomore students. Main Outcome Measures: Factors influencing weight and weight-related behaviors among undergraduates. Analysis: Qualitative analysis using a specific thematic approach, identifying themes appearing consistently across transcripts from recorded sessions. Results: Major themes that emerged in describing important influences on weight, dietary intake, and physical activity included: unhealthful food availability on campus, snacking, late-night eating, alcohol-related eating, eating because of stress/boredom, and food in student dorm rooms. Other factors related to physical activity included: negative experiences using campus recreation facilities; poor weather; and lack of time/time management, motivation, and social support for exercise. Conclusions and Implications: A wide range of factors may underlie weight gain and unhealthful diet and physical activity patterns during the college years. Young adulthood is an important and overlooked area for obesity prevention efforts. Universities need to take an active role in designing and evaluating weight-related health promotion intervention strategies focusing on a variety of targets, including individual-, social-, and environmental-level influences.
Hatchability of Chicken Eggs as Affected by Dietary Phosphorus and Calcium

Abstract Two experiments with caged egg-type hens and one experiment with broiler breeder hens on litter floors were conducted to determine interactions between dietary calcium and phosphorus as related to hatchability and other production characteristics. Reductions in hatchability of eggs from caged layers caused by suboptimal levels of inorganic phosphorus were partially offset by elevation of the dietary calcium. When phosphorus in the diet of caged layers was supplied entirely from plant sources, elevation of dietary calcium resulted in decreased hatchability and egg production. Hatchability of fertile eggs from broiler breeder hens on litter floors was not significantly affected by dietary calcium levels of 2.25 to 3.50%, or by total phosphorus levels of .31 to 1.42%. Egg production was improved by supplementation of the diet with inorganic phosphorus up to .41% total phosphorus, but it was depressed by further supplementation. Egg specific gravity decreased with increased phosphorus levels and was significantly depressed by high dietary phosphorus (1.42%). Recycling of phosphorus by coprophagy may be a factor affecting dietary phosphorus requirements of hens in litter floor pens.
Structure, cytochemistry, endocytic activity, and immunoglobulin (Fc) receptors of rat testicular interstitial‐tissue macrophages

Macrophages are common in rat testicular interstitial tissues. Interstitial-tissue macrophages were characterized using ultrastructural, cytochemical, immunologic, and autoradiographic methods. Testicular interstitial-tissue macrophages have a single indented nucleus, paranuclear Golgi complex, rough endoplasmic reticulum, coated vesicles, and numerous heterogeneous lysosomal vacuoles. Long filopodia and lamellopodia extend from the macrophage cell body into the lymphatic space. Macrophages are usually found adjacent to Leydig cells, and numerous Leydig cell processes are inserted into coated membrane invaginations on the macrophage surface. Secondary lysosomal vacuoles in the macrophage are cytochemically reactive for acid phosphatase (trimetaphosphatase) and aryl sulfatase. Testicular interstitial macrophages are endocytically active, avidly incorporating exogenously administered trypan blue dye and monomeric plutonium-citrate. Macrophages were isolated from the testes by allowing them to adhere to glass. The isolated macrophages were found to have receptors for the Fc portion of immunoglobulin G on their surface. The association of macrophages with Leydig cells and their endocytic and immunologic activity suggests that these cells may play an important role(s) in testicular functions. In addition, the ability of these cells to incorporate exogenous materials indicates that they could have a role in gonadal toxicity reactions.
Effects of term limits on fiscal performance: Evidence from democratic nations *

Political reputation models feature forward-looking, rational voters who re-elect incumbents based on their estimate of an incumbent's ability level. Fiscal policy is one of the ways an incumbent establishes a reputation and thereby signals this ability level to voters. The reputation-building framework implies that term limits should affect fiscal performance; a term-limited incumbent places less value on reputation-building than an incumbent eligible for re-election does. We examine differences in fiscal performance in democratic countries under alternative executive term limit regimes. Our results generally agree with the prior findings of Besley and Case (1995a) who analyzed gubernatorial term limits in the American States. We provide new evidence that the fiscal effects of term limits differ under a two-term rule versus a single-term rule.
Molecular‐weight dependence of the low‐frequency dielectric properties of aqueous solutions of gel‐fractionated DNA

Combined three- and four-terminal AC bridge measurements have been made at frequencies from 10 Hz to 100 KHz on samples of DNA with different molecular weight in aqueous solution under varying conditions of DNA concentrations and added salt. A method is described for the separation of large quantities of DNA fractionated according to size. A complicated pattern of dependence of the specific dielectric increment on concentration is found, and the difficulties of comparing the results from sample to sample are discussed. The dielectric properties of the fractionated samples of DNA in aqueous solution are reported for solutions sufficiently dilute that specific dielectric increment is independent of concentration. The specific dielectric increment of the solutions (with concentration measured in moles of DNA molecules/liter) is found to increase as the square of the molecular weight. The results are compared with results of polyelectrolyte theories which deal explicitly with counterion fluctuations and interactions. The frequency dependence of the dispersion is much broader than for simple Debye relaxation. It is satisfactorily fitted by the empirical Cole–Cole circular are function and the breadth of the dispersion is found to be, if anything, less for the fractionated samples than for native DNA in solution.
Logistic growth in the presence of non-white environmental noise.

Abstract A method is given for studying realistic random fluctuations in the carrying capacity of the logistic population growth model. This method is then applied using an environmental noise based on a Poisson process, and the time-dependent moments of the population probability density calculated. These moments are expressed in terms of a parameter obtained by dividing the correlation time of the environmental fluctuations by the characteristic response time of the population. When this quotient is large (very slow fluctuations tracked by the population) or small (very rapid fluctuations which are averaged), exact solutions are obtained for the probability density itself. It is also shown that at equilibrium, the average population sizes given by these two exact solutions bound all other cases. Numerical simulations confirm these developments and point to a trade-off between population stability and average population size. Additional simulations show that the probability of becoming extinct in a given time is greatest for populations intermediate between tracking and averaging the carrying capacity fluctuations. In addition to specifying when environmental noise can be ignored, these results indicate the direction in which growth parameters evolve in a fluctuating environment.
Neuronal differentiation in vitro from precursor cells of regenerating spinal cord of the adult teleost Apteronotus albifrons

This study documents neuronal differentiation in vitro from undifferentiated precursor cells of caudalmost regenerating spinal cord of the teleost Apteronotus albifrons. At 11 days in vitro, cells from the caudalmost tip of the regenerating cord are flat and polygonal in shape, lack neuronal processes and do not stain with antibody against neuron-specific filaments. At 15 days in vitro, some of the caudalmost cells have developed short, neurite-like processes; at 18 days in vitro, some cells react positively with antibody against neuron-specific filaments. At 26 days in vitro, many of the caudalmost cells have long branching neurites and react positively with anti-neurofilament antibody. Addition of insulin-like growth factor-I to the medium accelerates the process of neuronal differentiation from the caudalmost precursor cells in vitro. The source of these precursor cells is ultimately cells of the ependymal layer of adult spinal cord. Further investigation of the factors that control production and differentiation of these cells will be important in defining the developmental potential possible for vertebrate spinal cord cells and may aid in creating an optimal environment for regeneration of axons within mammalian spinal cord.
Neutron-Deficient Nuclides of Hafnium and Lutetium

New neutron-deficient nuclides of lutetium and hafnium were produced by bombarding lutetium oxide with 300- to 400-Mev protons. The genetic relationships and mass assignments were established by means of high-purity chemical separations and a series of chemical isolation experiments in which the daughter activity was determined as a function of time.The positron spectra of the different nuclides were measured with an anthracene crystal detector and a 256-channel pulse height analyzer. Gamma radiation was also observed for ${\mathrm{Lu}}^{168}$, ${\mathrm{Lu}}^{169}$, ${\mathrm{Lu}}^{170}$, ${\mathrm{Hf}}^{168}$, and ${\mathrm{Hf}}^{169}$ by means of a NaI crystal detector and the pulse height analyzer. The half-lives and maximum positron energies observed are: ${\mathrm{Lu}}^{168}$, ${T}_{\frac{1}{2}}=7.0$ min, ${E}_{{\ensuremath{\beta}}^{+}}=(1.20\ifmmode\pm\else\textpm\fi{}0.05)$ Mev; ${\mathrm{Lu}}^{169}$, ${T}_{\frac{1}{2}}=1.5$ days; ${\mathrm{Lu}}^{170}$, ${T}_{\frac{1}{2}}=1.9$ days, ${E}_{{\ensuremath{\beta}}^{+}}=(1.8\ifmmode\pm\else\textpm\fi{}0.1)$ Mev; ${\mathrm{Hf}}^{168}$, ${T}_{\frac{1}{2}}=22$ min, ${E}_{{\ensuremath{\beta}}^{+}}=(1.7\ifmmode\pm\else\textpm\fi{}0.1)$ Mev; ${\mathrm{Hf}}^{169}$, ${T}_{\frac{1}{2}}=1.5$ hr; ${\mathrm{Hf}}^{170}$, ${T}_{\frac{1}{2}}=9$ hr.
Polysensory responses and sensory interaction in pulvinar and related postero-lateral thalamic nuclei in cat.

Abstract Mapping of evoked responses in the pulvinar and adjacent nuclei of the thalamus in the cat under chloralose anesthesia and in the unanesthetized brain (Flaxedil and local anesthesia) was carried out for visual, auditory and somatosensory stimuli. Results have revealed that this region is a polysensory convergence center since all three sense modes produced responses which were widely distributed, although in a regionally differentiated fashion. Visual responses were more prominent in the postero-lateral region than in other regions of the pulvinar or than in other association nuclei. Similarly auditory and somatosensory responses, though overlapping in their spatial distributions, showed a magnitude differential in certain regions, usually those closest to the specific relay nucleus of the particular modality concerned. The nature and distribution of the responses under chloralose and in the absence of general anesthesia (Flaxedil and local anesthesia) were similar but the responses were larger and of longer latency under chloralose. In addition to the mapping of responses a comparison of the latencies was carried out, as well as recovery cycle and intermodality interaction tests. The latency and recovery cycle results tended to confirm the regional differentiation observed in the mapping studies. In the intermodality interaction tests visual stimuli were found to be dominant over auditory and somatosensory stimuli in postero-lateral pulvinar, and auditory stimuli were dominant over somatosensory stimuli. This latter result is discussed in terms of its implications for attentional and discrimination coding of sensory stimuli. Preliminary micro-electrode studies relevant certain temporal correspondences between unit discharges and evoked potentials in the pulvinar, as well as with the secondary or late waves recorded in the visual cortex.
Antileukocyte adhesion therapy : preclinical trials and combination therapy

Leukocytes appear to potentiate CNS reperfusion injury by clogging the microcirculation and infiltrating into the brain, where they release free radicals and other substances toxic to neurons. The initial step in these processes is leukocyte to endothelial cell adhesion. Both the microcirculation obstruction and the brain infiltration can be decreased by the use of specific monoclonal antibodies directed against leukocyte adhesion receptors. Experimental studies have found reduced stroke damage when antibodies that bind to either the CD-18 leukocyte adhesion molecule or its endothelial cell ligand, intercellular adhesion molecule-1 (ICAM-1), are used. Here we review the components of leukocyte to endothelial adhesion, preclinical studies of antileukocyte adhesion agents, and preclinical studies investigating combining anti-adhesion therapy with thrombolytics. Leukocyte to endothelial cell adhesion. The migration of leukocytes from the blood into the brain is a multistep process. First, primary leukocyte-endothelial interaction (rolling) occurs. This process is mediated by P-selectin and E-selectin on the surface of the endothelial cells and by L-selectin on leukocytes1 (figure 1). On activation, firm adherence of leukocytes to the endothelial lining(sticking) is subsequently mediated by a leukocyte membrane glyco-protein receptor complex, termed CD-18 or β2-integrin, and its endothelial ligand, the ICAM-1.2,3 The CD-18 integrin complex consists of three heterodimers. All three share an identical β-subunit(also frequently called CD-18) and are distinguished from each other by distinct α-subunits. The three α-subunits are termed leukocyte function antigen (LFA-1 or CD-11a, present on all leukocytes), MAC-1 (CD-11b, present mostly on PMNs and monocytes), and P150 (CD-11c, present on neutrophils and monocytes). The corresponding counter-receptors for the CD-18 integrin complex are the ICAM family of adhesion molecules. Whereas ICAM-1 is widely expressed on many cells and binds to LFA-1 and MAC-1, ICAM-2 is expressed only on endothelial cells and leukocytes and is recognized only by LFA-1.4 Unlike …
Martingales and stochastic integrals in the theory of continuous trading

This paper develops a general stochastic model of a frictionless security market with continuous trading. The vector price process is given by a semimartingale of a certain class, and the general stochastic integral is used to represent capital gains. Within the framework of this model, we discuss the modern theory of contingent claim valuation, including the celebrated option pricing formula of Black and Scholes. It is shown that the security market is complete if and only if its vector price process has a certain martingale representation property. A multidimensional generalization of the Black-Scholes model is examined in some detail, and some other examples are discussed briefly.