cssi/SciSciGPT-SciSciNet huggingface dataset:
Sub-critical intergranular crack growth of iron and nickel

The sub-critical intergranular crack growth behavior of iron and nickel showed several similarities and a few differences. The fracture thresholds and intergranular crack growth rates of iron and nickel were very similar which is consistent with the previously observed similarity of the effect of segregated sulfur and cathodic hydrogen on the fracture mode transition of these materials. The differences in their sub-critical crack growth behavior included the presence of a stage III crack growth regime in iron and its absence in nickel and the decrease in the fracture threshold of iron, K /SUB TH/, with increasing cathodic potential and the absence of a dependence of the K /SUB TH/ of nickel on cathodic potential. The present results were obtained with the same material used for the fracture mode transition tests but with compact tension (CT) samples in which the fracture mode was 100% intergranular for all cathodic potentials. Therefore, the present results represent the effect of cathodic potential on the intergranular crack growth rates of iron and nickel with large grain boundary sulfur concentrations (about 0.3 monolayers). The sub-critical crack growth behavior of iron and nickel with 0.3 monolayers of sulfur in their grain boundaries is similar. The fracture thresholdsmore » and Stage II crack growth rates are comparable; however, Stage III crack growth was observed in iron and not in nickel. The absence of Stage II crack growth in nickel was related to the large plastic zone size in nickel (about 47 mm) as compared to iron (about 2.6 mm).« less
Career Outcomes of STEM and Non-STEM College Graduates: Persistence in Majored-Field and Influential Factors in Career Choices

Using data from a nationally representative, longitudinal survey of college graduates, this study examines student transition from college to their chosen career paths and identifies factors influencing college graduates’ choosing an occupation related to ones’ undergraduate major. Within the context of expanded econometric framework a wide range of variables are considered, including monetary and nonmonetary costs and benefits as well as cultural and social capital measures. Using multinomial logit regression analyses, the results suggest positive career outcomes associated with individuals who have an occupation closely related to their college major, such as a better income profile and greater job satisfaction. Major-based differences are also examined between STEM and non-STEM graduates, and patterns of changes are documented for 10 years after graduation. An important perspective offered by this study is to consider career outcome as an extended definition of institutional effectiveness and student success. Based on the empirical findings, policy implications are discussed with the hope of bringing attention and improvement to the relationship between the higher educational system and the labor market.
Introducing Electronic Design Automation Tools into the Engineering Curriculum

The incorporation of electronic design automation (EDA) tools in engineering curricula will better prepare graduates to enter the modern engineering marketplace. The engineering courses appropriate for EDA introduction are discussed, as are the tools themselves and their sources. Issues of computing platform, operating system, and tool suites are presented. Internet accessible public domain documents are provided to aid engineering schools in setting up a comprehensive EDA curriculum.
Luminescence of mass-selected CuAg in argon matrices

Abstract We report on an observation of the luminescence spectrum of mass-selected CuAg in an argon matrix. Although no Raman spectrum is obtained, an emission progression up to ν ″=5 is observed, corresponding to the A0 + –X 1 Σ + transition observed in the gas phase. The origin of the transition is determined to be 20 262 (10) cm −1 . We obtain a value of ω e ″=223.8(4.9) cm −1 , which is consistent with the gas-phase observations.
Changes in growth rate and infectivity of Leishmania donovani subjected to various laboratory procedures.

Two substrains ofLeishmania donovani strain 3S were used in a study of grwoth rates of promastigote and amastigote stages as well as of infectivity of the latter stages in the course of cultivation, animal passages, and heat adaptation. One of these substrains, 3S-25A, was initiated with amastigotes of strain 3S maintained by serial passages in golden hamsters since 1962. The 3S-25A promastigotes were transferred 24 times (about 142 generations), then passaged once in a hamster. The amastigotes derived from this hamster on postinoculation day 30 were employed for initiation of culture promastigotes designated as substrain 3S-25A′. This culture was transferred 20 times (about 141 generations). The third substrain, 3S-37, was isolated in culture in 1974, then adapted to 37° C. All cultures were grown in modified Tobie's medium (Tm). Young C57BL/6J mice were employed in the estimation of generation times (G) of amastigote stages and infectivity of promastigotes.
Multimodality Therapy of Esophageal Cancer

Multimodality therapy of esophageal cancer has been evaluated inseveral clinical trials, with positive results in terms of improvedsurvival compared with single-modality therapy. A case report ispresented describing the use of paclitaxel in a multimodality regimenfor a patient with a bulky esophageal tumor. In addition, results aredescribed of a clinical trial in which patients received apaclitaxel-based regimen as part of multimodality therapy foresophageal cancer.
Laboratory Diagnosis of Tropical Infections

This article covers the laboratory diagnosis of infections that occur predominantly in the tropics. The discussion includes diagnosis of blood and tissue parasites, intestinal parasites, and tropical infections caused by fungi, bacteria, and mycobacteria. The laboratory performance of techniques for the identification of intestinal parasites and special requirements for the collection of specimens for virology testing are also discussed. Images demonstrating the characteristic features of selected tropical parasites and fungi are included for reference.
Influence of Serum of Normal and Pullorum-Infected Birds on the Bacteriostatic and Bactericidal Action of Sulfadiazine on Salmonella pullorum

Abstract IN studying the therapeutic value of sulfonamides in pullorum disease of poultry, Severens, Roberts and Card (1945) found that out of seven sulfonamides, sulfadiazine and sulfamerazine were the most effective, judged by both mortality and rate of gain of the surviving chicks. Anderson (1946), Mullen (1946), Anderson, Jones, Cooper and Morgan (1947), Eveleth, Goldsby and Bolin (1947), and MacNamee (1947) reported that the use of sulfamerazine in drinking water or in mash was effective in reducing the mortality due to pullorum disease. Bottorff and Kiser (1947) found that sulfamethazine, sulfadiazine or sulfamerazine caused a reduction in mortality among chicks. Pomeroy, Fenstermacher and Roepke (1948) reported that sulfadiazine, sulfamerazine, sulfapyrazine, sulfaquinoxaline and sulfamethazine were effective in reducing the mortality from pullorum disease in chicks. Sulfadiazine, sulfapyrazine, sulfaguanidine and sulfamerazine had little or no value in poults. The potentiating action of sulfonamides on the Brucella antibody-complement system has been reported by Huddleson . . .
Diffuse auroral precipitation in the jovian upper atmosphere and magnetospheric electron flux variability

Abstract The deposition of energetic electrons in Jupiter's upper atmosphere provides a means, via auroral observations, of monitoring electron and plasma wave activity within the magnetosphere. Not only does particle precipitation indicate a potential change in atmospheric chemistry, it allows for the study of episodic, pronounced flux enhancements in the energetic electron population. A study has been made of the effects of such electron injections into the jovian magnetosphere and of their ability to provide the source population for variations in diffuse auroral emissions. To identify the source region of precipitating auroral electrons, we have investigated the pitch-angle distributions of high-resolution Galileo Energetic Particle Detector (EPD) data that indicate strong flux levels near the loss cone. The equatorial source region of precipitating electrons has been determined from the locations of Galileo's in situ measurements by tracing magnetic field lines using the KK97 model. The primary source region for Jupiter's diffuse aurora appears to lie in the magnetic equator at 15 – 40 R J , with the predominant contribution to precipitation flux (tens of ergs cm−2 s−1 sr−1) stemming from 30 R J . Variability of flux for energetic electrons in this region is also important to the irradiation of surfaces and atmospheres for the Galilean moons: Europa, Ganymede, and Callisto. The average diffuse auroral precipitation flux has been shown to vary by as much as a factor of six at a given radial location. This variability appears to be associated with electron injection events that have been identified in high-resolution Galileo EPD data. These electron flux enhancements are also associated with increased whistler-mode wave activity and magnetic field perturbations, as detected by the Galileo Plasma Wave Subsystem (PWS) and Magnetometer (MAG), respectively. Resonant interactions with the whistler-mode waves cause electron pitch-angle scattering and lead to pitch-angle isotropization and precipitation.
Recurrence Rates of Aggressive Histologic Types of Basal Cell Carcinoma After Treatment with Electrodesiccation and Curettage Alone

BackgroundBasal cell carcinoma (BCC) is the most common cancer in Caucasians. Treatment options include electrodesiccation and curettage (EDC), surgical excision, and Mohs micrographic surgery (MMS). EDC is standard for smaller BCCs in low-risk locations with nonaggressive histologic subtypes. Large
Redox redux: A response to feinman's “oxidation-reduction calculations in the biochemistry course” (Biochem. Mol. Biol. Educ. 32, 161–166)

In a recent article, Richard Feinman suggested that we teach students to perform redox calculations in biochemistry by using the European rather than the American convention. In this article I raise a few objections (and correct a few errors). First, it's not clear that the European convention is any easier to use than the American. Second, students have already learned the American convention in freshman chemistry; why teach them a different method as upperclassmen? Last, by teaching a different problem-solving method in biochemistry than the one they learned in Introductory Chemistry, we lose an opportunity to show students how principles from “regular” chemistry apply to biological systems.
The cognition of change: scaling deformations in mind and spatial theories

The dynamics of the earth and its inhabitants have become a core topic and focus in research in the spatial sciences. The spatio-temporal data avalanche challenges researchers to provide efficient and effective means to process spatio-temporal data. It is of vital importance to develop mechanisms that allow for the transition of data not only into information but also into knowledge. Knowledge representation techniques from artificial intelligence play an important role in laying the foundations for theories dealing with spatio-temporal data. Specifically, the advances in the area of qualitative spatial representation and reasoning (QSTR) have led to promising results. Categorical distinctions of spatio-temporal information identified by QSTR calculi potentially correspond to those relevant to humans. This article presents the first behavioral evaluation of qualitative calculi modeling geographic events associated with scaling deformations of entities, that is, changes in size by either expansion or contr...
Importance of supernovae at z > 1.5 to probe dark energy

The accelerating expansion of the universe suggests that an unknown component with strongly negative pressure, called dark energy, currently dominates the dynamics of the universe. Such a component makes up ~70% of the energy density of the universe yet has not been predicted by the standard model of particle physics. The best method for exploring the nature of this dark energy is to map the recent expansion history, at which Type Ia supernovae have proved adept. We examine here the depth of survey necessary to provide a precise and qualitatively complete description of dark energy. Realistic analysis of parameter degeneracies, allowance for natural time variation of the dark energy equation of state, and systematic errors in astrophysical observations all demonstrate the importance of a survey covering the full range 0<z<2 for revealing the nature of dark energy.
Endogenous androgen concentrations in nuclei isolated from seminiferous tubules of mature rat testes.

Abstract A series of studies measured endogenous androgen concentrations by radioimmunoassay within nuclei prepared from seminiferous tubules of the adult male rat. Testosterone was the principal androgen in the nuclei and occurred in high concentration (0.3 ng/mg DNA). This concentration was maintained even after substantial purification of the nuclei, indicating that the concentrations of testosterone measured were not the result of cytoplasmic contamination. Testosterone was actively retained in these nuclei following hypophysectomy of the animal: nuclear testosterone concentration fell to 20% of that in intact animals, while serum testosterone concentration fell to 3%. About 70% of the testosterone within the nuclei could be extracted with buffers containing KCl. Data from titration of testosterone in the salt extract of nuclei and in their residue generated a regression line which passed through the origin. Initial observations showed that salt-extracted testosterone could be separated into bound and free fractions by chromatography and that the bound portion was approx. 55% of total. It is suggested that this methodology is appropriate for the study of the relation of androgen binding to spermatogenesis in the seminiferous tubules of normal animals.
Stomach emptiness in fishes: Sources of variation and study design implications

This study summarizes fish stomach content data from 369,000 fish from 402 species in 1,096 collections and reports on the percentage of individuals with empty stomachs. The mean percentage of individuals with empty stomachs among all species, locations, habitats, seasons, regions, and collection methods was 26.4%. Mean percentage of individuals with empty stomachs varied significantly among fish collection gear types, taxonomic orders, trophic groups, feeding behaviors, and habitats, and with species length at maturity. Most of the variation in percentage of individuals with empty stomachs was explained by species length at maturity, fish collection gear type, and two autecological factors: trophic group (piscivore percentage of individuals with empty stomachs > non-piscivore percentage of individuals with empty stomachs) and feeding habitat (water column feeder percentage of individuals with empty stomachs > benthic feeder percentage of individuals with empty stomachs). After accounting for variation wi...
143 TRANSCRIPTIONAL PROFILING BY HIGH-THROUGHPUT SEQUENCING OF PORCINE PRE- AND PERI-IMPLANTATION EMBRYOS

Significant embryo mortality occurs at or around the time of implantation or attachment in virtually all mammalian species studied to date, even in naturally conceived embryos. Embryos resulting from assisted reproductive technologies (ART) are even more susceptible to peri-implantation failure. Herein we describe our effort to characterise the transcriptomes of embryonic disc (ED) and trophoblast (TE) cells from porcine embryos derived from AI, IVF, parthenogenetic oocyte activation (PA) and somatic cell nuclear transfer (NT) on Days 10, 12 and 14 of gestation. The IVF, PA and somatic cell NT embryos were generated using in vitro–matured oocytes, cultured overnight in vitro and then transferred at the 1- to 2-cell stage into appropriately synchronized recipient gilts. On the appropriate collection day, embryos were flushed from the uterus and ED was separated from TE by mechanical dissection. Double-stranded cDNA from the collected samples was sequenced using the GAII platform from Illumina (San Diego, CA, USA). The resulting sequencing reads were aligned to a custom swine transcriptome database (see Isom et al. 2010). A generalized linear model was fit for each of 41 693 genomic regions, for ED and TE samples separately, accounting for embryo type, gestation day and their interaction and using total lane read count as a normalizing offset. Genes with significant embryo type differences (controlling the false discovery rate at 0.10) were subsequently tested for differences between IVF and each of AI, PA and NT. Those genes with significant post hoc differences (either up- or down-regulated compared with IVF) were characterised in terms of gene ontologies and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways using a gene set enrichment test. Bone morphogenetic protein signalling was down-regulated (KEGG; P = 0.0099; adjusted to control for FDR at 0.05) in the ED of IVF embryos when compared with AI embryos. In TE cells from IVF embryos, ubiquitin-mediated proteolysis and ErbB signalling (adj P = 0.031 for both pathways) were aberrantly regulated when compared with AI embryos. Of particular interest is the observation that expression of genes involved in chromatin modification (GO:BiologicalProcess; q-value = 0.00005) and epigenetic regulation of transcription (q = 0.00007) was very significantly disrupted in inner cell mass cells from NT embryos compared with IVF embryos. Surprisingly, no such disruption of the epigenetic machinery was observed in the TE cells from NT embryos. In summary, we have used high-throughput sequencing technologies to compare gene expression profiles of various ART embryo types during peri-implantation development. We expect that these data will provide important insight into the root causes of (and possible opportunities for mitigation of) suboptimal development of embryos derived from ART. Funding was received from NIH R01 RR013438 and Food for the 21st Century (RSP) and the Utah Agricultural Experiment Station (UTA00151 and UTA00560 for S. C. Isom and J. R. Stevens, respectively).
The concept of equilibrium: A key theoretical element in Keynes' revolution

This paper presents Keynes' concept of equilibrium, which was one key theoretical element that constituted the theoretical core of the General Theory and was critical in his attack on the classical model. Keynes' concept of equilibrium differed in structure, content, and purpose from that of the neoclassical orthodoxy. There were four unique features of Keynes' equilibrium and these features all reflect his overriding focus on involuntary unemployment. First, Keynes' equilibrium reflected a purposive function that differed in its maximand and normative content from his predecessors. Second, Keynes' equilibrium reflected the fact that the composition of national income determined the level of aggregate demand, which in turn determined of the equilibrium level of national income and employment. Third, his notion of equilibrium was based on use of the ex ante-ex post analysis. Finally, Keynes' equilibrium presented an alternative view of market-clearing.
Beyond Legislative Advocacy: Exploring Agency, Legal, and Community Advocacy

This study examined institutional factors that influence the non-legislative advocacy targets chosen by human service nonprofits. Formalization, restricted funding, professionalization, and knowledge of the lobbying law were used as predictors. Overall advocacy participation was also addressed. Results showed that knowledge of the lobbying law was a significant predictor of agency and community advocacy. None of the predictors were significant factors in legal advocacy. Results discuss the importance of non-legislative advocacy and highlight the need for additional research as well as education regarding advocacy that goes beyond influencing policy.
Providing Improved Power Quality in Microgrids: Difficulties in Competing with Existing Power-Quality Solutions

Much of the microgrid literature assumes that providing improved power quality, i.e., eliminating short-duration disturbances by seamless islanding, is a fundamental objective for microgrids. however, seamless islanding adds significant cost through high energy-storage and inverter rating requirements. Power quality microgrids will face significant barriers in competing with the existing power-quality solutions due to customer perception against exposing critical loads to disturbances and the challenge of supplying a level of power quality com-parable with the existing solutions. Achieving 1/4-cycle or faster response time is difficult with the common distributed line interactive microgrid architecture because of distributed generation interfering with forced commutation of the static switch. To avoid adding unnecessary cost, three main value propositions for microgrids are identified: reliability; energy arbitrage; and power quality. Requirements and characteristics are described for microgrids designed for each of the three value propositions, and sample designs are compared for an example case.
The role of opioid receptor internalization and beta-arrestins in the development of opioid tolerance.

Opioid tolerance, a phenomenon characterized by decreased analgesic effects obtained by the same dose of opioids after repeated use of the opioids, is a significant clinical problem. Traditional theory attributes receptor desensitization and internalization and post-receptor adaptation to the develo
Mapping a cluster of ribosomal genes in Escherichia coli

Escherichia coli strains carrying ribosomal and nonribosomal mutations were used to perform mapping experiments to determine the relative order of various genes which code for ribosomal proteins. The strains used carried the two nonribosomal mutations, crp and aro E, which seem to flank the ribosomal genes. They also carried mutations which conferred resistance to erythromycin, kanamycin, neomycin, spectinomycin, and streptomycin, and mutations which conferred dependence on or independence from streptomycin. A series of transduction experiments together with some data from the literature suggest the following order: crp, k12, str, str i (ram), eryA, eryB, spc, nek, aroE. Thus far no nonribosomal gene is located between ribosomal genes, and at least some 50S ribosomal genes are interspersed between 30S genes.
Long Range Surface Plasmon Devices Design Using Subwavelength Metal Grating

In this paper we review a new electro-optic devices design strategy using long range surface plasmon (LRSP) excitation along subwavelength metal grating. It is shown that LRSP can be excited on extremely thin subwavelength metal grating embedded in symmetric dielectric ambient. Due to coupling and propagation of LRSP between the metal grating nanowires, a super-narrow reflection dip can be obtained. Compared with conventional LRSP along metal thin film, much narrower resonance is achieved through decreased damping from the existence of large dielectric gaps between the grating nanowires. This interesting phenomenon can be used to design electro-optics devices with improved performance. Examples of electro-optic modulator design with lower insertion loss and low operating voltage and spectral notch filter design with very narrow spectral width will be shown. Its application in refractive index sensing is also discussed.
The incidence of new onset congestive heart failure and heart failure exacerbation in Veteran's Affairs patients receiving tumor necrosis factor alpha antagonists.

The objective of this study was to evaluate the incidence of new onset or worsening congestive heart failure in Veteran’s Affairs (VA) patients who have received infliximab, etanercept, or adalimumab, and to compare mortality rates in these patients to control populations. We enrolled three groups of patients for this retrospective study: TNF-α group (n = 103), a rheumatoid arthritis (RA) control group (n = 100), and a control group without RA (n = 100). All patients at our VA facility who had received at least one dose of the TNF-α antagonists were included in the TNF-α group. Admissions for CHF did not differ between the three groups: TNF-α 7 (6.7%), RA control 8 (8%), non-RA control 7 (7%); P = 0.940. Mortality rates were not significantly different: TNF-α 4 (3.8%), RA control 7 (7%), non-RA control 11 (11%); P = 0.147. Our study showed no difference between the three groups in either CHF exacerbation or mortality.
Serum 25-Hydroxy Vitamin D and Survival in Advanced Colorectal Cancer: A Retrospective Analysis

Higher serum 25-hydroxy vitamin D [25(OH)D] levels are associated with decreased colorectal cancer (CRC) incidence. In this retrospective study of Stage IV CRC patients, we evaluate whether 25(OH)D levels at diagnosis correlate with survival. Stored sera from carcinoembryonic antigen (CEA) measurements obtained between February 2005 and March 2006 were screened. The first 250 patients with CEA ± 30 days of Stage IV CRC diagnosis were included. Serum 25(OH)D levels were determined and categorized as adequate ≥ 30 ng/mL, or deficient <30 ng/mL. Multivariable Cox regression models controlling for albumin and Eastern Cooperative Oncology Group performance status were used to investigate whether higher 25(OH)D levels were associated with prolonged survival. A total of 207 patients (83%) were vitamin D-deficient (median = 21 ng/mL), with deficiencies significantly more likely among non-Hispanic black patients (P = 0.009). Higher levels were associated with prolonged survival in categorical variable analysis: adequate vs. deficient, hazard ratio = 0.61, 95% confidence interval = 0.38-0.98, P = 0.041. A majority of newly diagnosed Stage IV CRC patients are vitamin D-deficient. Our data suggest that higher 25(OH)D levels are associated with better overall survival. Clinical trials to determine whether aggressive vitamin D repletion would improve outcomes for vitamin D-deficient CRC patients are warranted.
Simple models of energy flow in vibrating membranes

Abstract A simplified model of the energy distribution and energy flow in membranes is derived using a loss factor damping model, an energy balance and a simplified energy transmission relationship. The energy transmission relationship is derived by smoothing a generalized plane wave representation of the energy density and intensity in the membrane. For smoothed conditions, the intensity is proportional to the spatial derivatives of the energy density. The resulting energy model is a second order differential equation which predicts the smoothed energy distribution and intensity in a membrane. The capabilities of the model are illustrated for four cases of broadband excitation of a point excited membrane.
The Detection and Characterization of Blisters On Carbon-Graphite Mechanical Seal Faces

Blisters that develop on carbon-graphite mechanical seal faces are irregularities in surface topography that result in poor sealing performance and a high incidence of catastrophic failure. On first inspection, a blister is a burnished area that is slightly elevated above the surrounding seal surface. In this study, the topography of several hundred blisters was examined with interference microscopy. The shape of the burnished area is typically elliptical or cylindrical. The leading edge against the direction of rotation of the mating seal ring extends abruptly upward from the surrounding seal surface. The trailing surface gradually merges into the parent seal face. Most blisters have a maximum height of 0.25 μm to 0.75 μm (10 μ-in to 30 μ-in). Presented at the 55th Annual Meeting Nashville, Tennessee May 7–11, 2000
Selective instability of Orc1 protein accounts for the absence of functional origin recognition complexes during the M–G1 transition in mammals

To investigate the events leading to initiation of DNA replication in mammalian chromosomes, the time when hamster origin recognition complexes (ORCs) became functional was related to the time when Orc1, Orc2 and Mcm3 proteins became stably bound to hamster chromatin. Functional ORCs, defined as those able to initiate DNA replication, were absent during mitosis and early G1 phase, and reappeared as cells progressed through G1 phase. Immunoblotting analysis revealed that hamster Orc1 and Orc2 proteins were present in nuclei at equivalent concentrations throughout the cell cycle, but only Orc2 was stably bound to chromatin. Orc1 and Mcm3 were easily eluted from chromatin during mitosis and early G1 phase, but became stably bound during mid-G1 phase, concomitant with the appearance of a functional pre-replication complex at a hamster replication origin. Since hamster Orc proteins are closely related to their human and mouse homologs, the unexpected behavior of hamster Orc1 provides a novel mechanism in mammals for delaying assembly of pre-replication complexes until mitosis is complete and a nuclear structure has formed.
Theoretical Analysis of Heteroaromatic Thioaminyl Radicals. Part 2: A Comparison of Ab Initio and Density Functional Methods in the Description of Redox Processes†

Gas-phase electron-transfer processes for 12 known thioaminyl radicals belonging to 7 general classes of heterocycles have been investigated using the HF and B3LYP methods with 6-31G(d) basis set augmented with diffuse functions. The basis set was chosen based on favorable comparison of the theoretical and experimental normal modes for 1a. The calculated ionization potentials (Ip) and free energy changes were subsequently compared with the experimental Ip and electrochemical redox potentials. It was found that the DFT method performs better than the HF method giving excellent correlations for vertical Ip and ℰ red1/2 (ℛ 2 > 0.98), but not for ℰ ox1/2 or ℰcell (ℛ 2 = 0.7). The calculated disproportionation energies were compared with the available conductivity data for radicals showing a qualitative correlation. Generally, low disproportionation energies and hence high conductivity are obtained for large π systems, such as 11, containing the −N−S−S− array of heteroatoms. The established correlations provid...
The reaction of 1-chloro-2-methyl-1-propenyllithium with a selection of organolithiums. The development and synthetic utility of novel base/nucleophile combinations

Abstract The title compound was generated by and reacted with (1) a series of reagents which have basic as well as nucleophilic properties and (2) a series of b
Stochastic resonance at the molecular level.

Stochastic resonance (SR) has received renewed interest since having been demonstrated in sensory biology a few years ago. It is the process, evident in a class of nonlinear systems subject to weak input signals, whereby the introduction of a random process, or "noise" as it is called, can enhance the information content at the output of the system. Introduced in 1981 by Angelo Vulpiani and others as a theory of the periodic recurrences of the Earth's ice ages (Nicolis, 1993), it was later applied to a wide variety of physical systems, eventually moving to biology (Moss and Wiesenfeld, 1995) and even medical science, as shown by the innovative experiments of Faye Chiou-
DIF Detection and Effect Size Measures for Polytomously Scored Items

Data from a large-scale performance assessment (N= 105,731) were analyzed with five differential item functioning (DIF) detection methods for polytomous items to examine the congruence among the DIF detection methods. Two different versions of the item response theory (IRT) model-based likelihood ratio test, the logistic regression likelihood ratio test, the Mantel test, and the generalized Mantel–Haenszel test were compared. Results indicated some agreement among the five DIF detection methods. Because statistical power is a function of the sample size, the DIF detection results from extremely large data sets are not practically useful. As alternatives to the DIF detection methods, four IRT model-based indices of standardized impact and four observed-score indices of standardized impact for polytomous items were obtained and compared with the R2 measures of logistic regression.
Bismuth magnesium titanate, an unusual new perovskite

Bismuth magnesium titanate, a new and apparently peritectic compound, has been prepared and shown to crystallize in the ideal cubic perovskite structure with a = 3·98 A and the structural formula (Bi0·8Mg0·2)(Mg0·3Ti0·650·05)O3. The atomic position assignments are based on structure factor calculation, but the placement of the fractional vacancy is the result of Goldschmidt tolerance factor considerations. The compound's tolerance factor is just about 0·8. Aspects of the new compound which combine to make it rather unusual are discussed.
Development of a numerical integration area source algorithm for industrial source complex long term (ISCLT) model

Abstract The Previous model evaluation studies have shown the deficiencies of the virtual point source algorithm for modeling area sources used in the ISCLT2 model. This paper documents the development, testing, and evaluation of a new numerical integration algorithm for modeling area source for the ISCLT2 model. This algorithm, which is based on the numerical integration for area source recently implemented in the ISCST2 model, allows users to handle the complex geometry of irregularly shaped area sources, and allows the calculation of the area source impact for receptors located within and nearby the area source. Detailed performance tests, statistical analyses, and sensitivity analyses have been completed to assure the reliability and reasonableness of the modeling results. The algorithm has been compared with the currently used ISCLT2 virtual point source algorithm, as well as with the numerical integration area source algorithm for the ISCST2 model. The results show that the new numerical integration ISCLT2 area source algorithm performs very well. Using idealized meteorological conditions, the new algorithm achieves very good comparison results when compared with the newly developed ISCST2 area source algorithm. It is also concluded that the currently used ISCLT2 area source algorithm based on the virtual point source approach underestimates the concentration value by a factor of about 2 or 4, especially when the receptors are located inside or near the source.
Criteria for the use of Vertical Averaging in Great Lakes Dispersion Models

Two basic questions that arise in the development of Great Lakes dispersion models are (1) when can vertical averaging be used to reduce the dimensionality of the problem, and (2) what value(s) should be used for the horizontal dispersion coefficient(s)? A strategy is presented here for estimating answers to both of these questions. A reasonable requirement for the use of vertical averaging is shown to be an elapsed time of dispersion, t1, which is the time required for the horizontal variance of the concentration to reach a linear growth rate in time. This time is t1=H2/(α1K¯Z) where H is average depth, K¯z is the average vertical diffusivity and α1 is determined from the numerical solution of a model dispersion problem for each velocity and diffusivity profile used. A corresponding horizontal effective dispersion coefficient, Ke, to be used in the vertically integrated model Ke=C1H2U2/K¯Z where Umax is a reference velocity and C1 is obtained numerically for each velocity and diffusivity profile. Values of α1 and C1 are computed for two cases. Application of the strategy is illustrated using dispersion modeling in the Western Basin of Lake Erie as an example. Predicted values for Ke are also compared with some previous measurements of horizontal dispersion in Lake Ontario.
Mechanisms of constipation in older persons and effects of fiber compared with placebo

OBJECTIVE: To investigate the mechanisms of constipation and the effect of fiber supplementation on physiology, mechanisms, stool parameters, and colonic transit times in a group of constipated older patients. DESIGN: Single-blind, randomized, placebo-controlled fiber intervention with crossover. SETTING: A university-based outpatient center. PATIENTS: Ten community-living older men and women, healthy except for chronic constipation. INTERVENTIONS: Patients were given either 24 g psyllium fiber or placebo fiber daily for 1 month, then crossed over to the other arm for an additional month. Structured testing, including total gut transit time and rectal and colonic manometry, was performed at the end of each intervention month. Patients recorded stool frequency, consistency, and weights daily. RESULTS: The predominant mechanism for constipation in these patients was outlet delay caused by pelvic dyssynergia. Fiber decreased total gut transit time from 53.9 hours (placebo condition) to 30.0 hours (P < .05). Stool weights and consistency were not significantly improved by fiber, though there was a trend toward an increase in stool frequency (1.3 vs 0.8 bowel movements per day.) Pelvic floor dyssynergia was not remedied by fiber, even when constipation was clinically improved. CONCLUSIONS: Fiber supplementation appeared to benefit constipated older patients clinically, and it improved colonic transit time, but it did not rectify the most frequent underlying abnormality, pelvic floor dyssynergia.
Late Oligocene sharks and rays from the Chandler Bridge Formation, Dorchester County, South Carolina, USA

A diverse vertebrate fauna, dominated by elasmobranch taxa, was collected from the upper Oligocene (Chattian) Chandler Bridge Formation in Summerville, Dorchester County, South Carolina. Nearly 3,500 teeth and dermal denticles are assigned to 29 species of sharks and rays, and our sample includes the oldest known occurrence of the whale shark, Rhincodon, as well as a new skate, Raja mccollumi sp. nov. The Chandler Bridge elasmobranch assemblage is comparable in species diversity to Chattian assemblages of Virginia and North Carolina, USA, and Germany. Notable absences from Germany include Rhincodon, Hemipristis, and Sphyrna zygaena, likely reflecting the influence of colder water on the North Sea Basin during the Chattian. Squaloids, pristiophoroids, and hexanchoids are known from Chattian deposits of the Albemarle Embayment (North Carolina), Salisbury Embayment (Virginia), and North Sea Basin, but these taxa are absent from the Chandler Bridge assemblage, perhaps because of shallow, warm water (20 to 25°...
Anterior Lens Capsule Rupture Caused by Air Bag Trauma

Purpose To report a child with anterior lens capsule rupture caused by air bag inflation. Methods A 10-year-old girl sustained a rupture of the right anterior lens capsule secondary to air bag deployment during a minor automobile accident. The evaluation included orbital ultrasound and orbital computed tomography. Result The right eye underwent lens aspiration with intraocular lens placement. Postoperatively, the patient did well with 20/25 best-corrected visual acuity. Conclusion Our case, in which the patient's lens capsule was ruptured by air bag inflation, illustrates that air bag deployment, even in minor low-speed accidents, can cause severe blunt trauma to the eye.
Cannabinoid receptor-mediated inhibition of the rat tail-flick reflex after microinjection into the rostral ventromedial medulla

Systemic administration of cannabinoids produce profound antinociception in rodents. The purpose of this study was to examine the contribution of the rostral ventromedial medulla (RVM) to cannabinoid-mediated inhibition of the tail-flick reflex. Rats received direct injections of two selective cannabinoid agonists, WIN55,212-2 and HU210, into the RVM. Both compounds significantly elevated tail-flick latencies by over 50%. WIN55,212-3, the inactive enantiomer, was without effect. Furthermore, co-administration of the selective cannabinoid receptor antagonist, SR141716A greatly attenuated the antinociception produced by HU210. Finally, injections of WIN55,212-2 outside the region of the RVM did not affect tail-flick latencies. These results demonstrate that the cannabinoid receptor system participates in the descending control of nociception and raise the possibility that actions of endogenous cannabinoids in the RVM may modulate nociceptive responsiveness.
Minority Students in Science: Perspectives from the 1981-1982 National Assessment in Science.

Minority students achieve less well in science, have less exposure to it, but have more positive attitudes toward science. There is a negative relationship between science-related experience and attitudes toward science.
An application of optimization methods to evaluate conditioning intervals

A decision rule is obtained to determine when exercise is beneficial. The term beneficial used in this context refers to the extension of lifetime based on studies of cardiovascular conditioning. Models are used to characterize changes in heart rate with intense exercise. In addition, it is necessary to consider a model involving a heartbeat bank to help determine the conditioning interval. Optimization procedures are used to develop the decision rule, to examine the assumptions in the problem, and to point out when a unique solution exists. This procedure is applied to empirical data for one individual (inter-subject study) and a unique conditioning interval is obtained.
Lipid metabolism in helminth parasites--VI. Synthesis of 2-cis,6-trans farnesol by Hymenolepis diminuta (Cestoda).

Abstract 1. 1. Hymenolepis diminuta did not synthesize squalene or cholesterol from C 14 -labeled acetate, hydroxymethylglutarate or mevalonate. 2. 2. All three intermediates were converted to 2- cis ,6- trans farnesol and much smaller amounts of 2- trans ,6- trans farnesol, the pyrophosphate derivative of the latter being the normal precursor for squalene and cholesterol synthesis in mammals. 3. 3. Both farnesol isomers are normal constituents of H. diminuta , in amounts approximating 25 μg and 2·6 μg/g wet wt., respectively. Farnesal and nerolidol were absent, but minor amounts of farnesyl or nerolidyl pyrophosphates were present. 4. 4. The presence of significant amounts of farnesols in H. diminuta is considered in relation to their possible juvenile hormone activity.
Purification and Biochemical Analyses of a Monomeric Form of Tn5 Transposase

The binding of transposase (Tnp) to the specific Tn5 end sequences is the first dedicated reaction during transposition. In this study, comparative DNA-binding analyses were performed using purified full-length Tnp and a C-terminal deletion variant (delta369) that lacks the putative dimerization domain. The shape of the binding curve of full-length Tnp is sigmoidal in contrast to the hyperbolic-shaped binding curve of delta369. This observation is consistent with previous observations as well as a rate of binding study presented here, which suggest that the full-length Tnp-end interaction, unlike that of the truncated protein, is a complex time-dependent reaction possibly involving a subunit exchange. Circular permutation assay results indicate that both proteins are capable of distorting the Tn5end sequences upon binding. Molecular weight determinations based on the migratory patterns of complexed DNA in polyacrylamide gels has shown that delta369 specifically binds the Tn5 end sequences as a monomer while full-length Tnp in complex represents a heterodimer.
Temperature and vital effect controls on bamboo coral (Isididae) isotope geochemistry: A test of the “lines method”

Deep-sea bamboo corals hold promise as long-term climatic archives, yet little information exists linking bamboo coral geochemistry to measured environmental parameters. This study focuses on a suite of 10 bamboo corals collected from the Pacific and Atlantic basins (250–2136 m water depth) to investigate coral longevity, growth rates, and isotopic signatures. Calcite samples for stable isotopes and radiocarbon were collected from the base the corals, where the entire history of growth is recorded. In three of the coral specimens, samples were also taken from an upper branch for comparison. Radiocarbon and growth band width analyses indicate that the skeletal calcite precipitates from ambient dissolved inorganic carbon and that the corals live for 150–300 years, with extension rates of 9–128 μm/yr. A linear relationship between coral calcite δ18O and δ13C indicates that the isotopic composition is influenced by vital effects (δ18O:δ13C slope of 0.17–0.47). As with scleractinian deep-sea corals, the intercept from a linear regression of δ18O versus δ13C is a function of temperature, such that a reliable paleotemperature proxy can be obtained, using the “lines method.” Although the coral calcite δ18O:δ13C slope is maintained throughout the coral base ontogeny, the branches and central cores of the bases exhibit δ18O:δ13C values that are shifted far from equilibrium. We find that a reliable intercept value can be derived from the δ18O:δ13C regression of multiple samples distributed throughout one specimen or from multiple samples within individual growth bands.
The sociodemographic correlates of the timing of divorce in Ghana.

Using the 1979/1980 World Fertility Survey data from Ghana the authors examine the social and demographic correlates of the timing of divorce. On the whole they found that marriages are quite unstable in the country. Within 10 years of marriage 23% of the women have dissolved their marriages. Of couples married in the 1970s 32% are expected to divorce within 10 years after marriage. Even though the traditional extended family has been undergoing rapid changes in the face of modernization there is no evidence that the various aspects of modernization have uniform effects in increasing divorce rates in Ghana. While aspects of modernization such as education age at marriage and smaller family size decrease the chances of a woman dissolving her marriage other trends such as rising female employment and urbanization increase the chances of divorce. The divorce problem in Ghana is thus seen as a mechanism for adjustment to conflicting influences rather than a problem of cultural crisis. (authors modified)