cssi/SciSciGPT-SciSciNet huggingface dataset:
Performance evaluation of a Terry GS-2 steam impulse turbine with air-water mixtures

Abstract Terry steam turbines are widely used in various industries because of their robust design. Within the nuclear power generation industry, they are used in the Reactor Core Isolation Cooling System to remove decay heat during reactor isolation events. During the Fukushima Daiichi nuclear power station disaster in Japan in 2011, the Reactor Core Isolation Cooling System and associated Terry turbine operated for over 70 hours in Unit 2; this runtime is well beyond the expected operating duration. Theories suggest the turbine was subjected to a two-phase inlet flow, which could degrade the turbine performance. In this work, an experimental test rig was constructed to test a full-scale Terry model GS-2 steam turbine under two-phase air/water flows. Steady-state efficiency and torque performance maps of the turbine were developed over a range of turbine inlet pressures (1.38–4.83 bar or 20–70 psia), air mass fractions (0.05–1.0) and rotational speeds up to 4000 RPM. Turbine performance followed expected trends with torque varying linearly and efficiency varying quadratically with rotational speed. In addition, high-speed images of the two-phase flow entering the turbine were also analyzed to understand how changes in inlet pressure and air mass fraction affect the flow regime and homogenization. The present tests with air–water two-phase mixtures are an important step towards providing an understanding of the full-scale Terry turbine’s behavior and performance curves under two-phase conditions. The results of this work will be combined with air/water and steam/water data gathered using a small-scale Terry ZS-1 steam turbine in order to understand the scaling relationship between large and small size Terry turbines and fluid pairs. The combined data set will enable further development of analytical models over a wide range of conditions and may be used to provide technical justification for expanded use of the Terry turbines in nuclear power plant safety systems and other systems.
Why Are Fewer Young Adults Having Casual Sex

Fewer young adults are engaging in casual sexual intercourse now than in the past, but the reasons for this decline are unknown. The authors use data from the 2007 through 2017 waves of the Panel S...
What Do Childcare Providers Know about Environmental Influences on Children's Health? Implications for Environmental Health Literacy Efforts.

Children are uniquely vulnerable to toxicant exposures in their environment, which can have long-lasting impacts on their health. Childcare providers are an important population to target for environmental health literacy, as most children in the United States under five years of age spend a significant number of waking hours in non-parental care. There is an increasing body of evidence that children are exposed to toxicants in the childcare environment, and yet little is known about what childcare providers know about environmental influences on the health of children in their care. We conducted semi-structured interviews with 36 home- and center-based Illinois childcare providers to better understand their knowledge, attitudes, and behaviors as they relate to environmental influences on children’s health. We found that the majority of providers had a low level of understanding of potential sources of exposure in the childcare environment, and they did not feel that environmental exposures posed a significant risk to children. Future efforts to increase environmental health literacy should focus on raising awareness and knowledge of environmental health issues for childcare providers before addressing ways that providers can reduce or prevent toxicant exposures to children in their care.
let-7 microRNAs: Their Role in Cerebral and Cardiovascular Diseases, Inflammation, Cancer, and Their Regulation

The let-7 family is among the first microRNAs found. Recent investigations have indicated that it is highly expressed in many systems, including cerebral and cardiovascular systems. Numerous studies have implicated the aberrant expression of let-7 members in cardiovascular diseases, such as stroke, myocardial infarction (MI), cardiac fibrosis, and atherosclerosis as well as in the inflammation related to these diseases. Furthermore, the let-7 microRNAs are involved in development and differentiation of embryonic stem cells in the cardiovascular system. Numerous genes have been identified as target genes of let-7, as well as a number of the let-7’ regulators. Further studies are necessary to identify the gene targets and signaling pathways of let-7 in cardiovascular diseases and inflammatory processes. The bulk of the let-7’ regulatory proteins are well studied in development, proliferation, differentiation, and cancer, but their roles in inflammation, cardiovascular diseases, and/or stroke are not well understood. Further knowledge on the regulation of let-7 is crucial for therapeutic advances. This review focuses on research progress regarding the roles of let-7 and their regulation in cerebral and cardiovascular diseases and associated inflammation.
Alkyne Hydrogenation Catalysis across a Family of Ga/In Layered Zintl Phases.

Transition-metal-free Zintl-Klemm phases have received little attention as heterogeneous catalysis. Here, we show that a large family of structurally and electronically similar layered Zintl-Klemm phases built from honeycomb layers of group 13 triel (Tr) or group 14 tetrel (Tt) networks separated by electropositive cations (A) and having a stoichiometry of ATr2 or ATrTt (A = Ca, Ba, Y, La, Eu; Tr = Ga, In; Tt = Si, Ge) exhibit varying degrees of activity for the hydrogenation of phenylacetylene to styrene and ethylbenzene at 51 bar H2 and 40-100 °C across a variety of solvents. The most active catalysts contain Ga with, formally, a half-filled pz orbital, and minimal bonding between neighboring Tr2 or TrTt layers. A 13-layer trigonal polytype of CaGaGe (13T-CaGaGe) was the most active, cyclable, and robust catalyst and under modest conditions (1 atm H2, 40 °C) had a surface specific activity (590 h-1) comparable to a commercial Lindlar's catalyst. Additionally, 13T-CaGaGe maintained 100% conversion of phenylacetylene to styrene at 51 bar H2, even after 5 months of air exposure. This work reveals the structural design elements that lead to particularly high catalytic activity in Zintl-Klemm phases, further establishing them as a promising materials platform for hydrogen-based heterogeneous catalysis.
HIV and Intersectional Stigma Reduction Among Organizations Providing HIV Services in New York City: A Mixed-Methods Implementation Science Project

Stigma remains a pervasive barrier to Ending the HIV Epidemic (EHE) in New York City (NYC). As part of an EHE implementation science planning process, we mapped multi-level HIV-related stigma-reduction activities, assessed their evidence base, and characterized barriers and facilitators. We interviewed and surveyed a convenience sample of 27 HIV prevention and/or treatment services organizations in NYC, March-August, 2020, using an embedded mixed-methods design. The greatest facilitators of stigma reduction included integration of health services, hiring staff who represent the community, and trainings. Intersecting stigmas were primarily addressed through the integration of HIV with mental health and substance use services. Barriers were multilevel, with organizational structure and capacity most challenging. A strong base of stigma-reduction activities was utilized by organizations, but intersectional frameworks and formal evaluation of activities' impact on stigma were lacking. Effectiveness-implementation hybrid research designs are needed to evaluate and increase the uptake of effective stigma-reduction approaches in NYC.
Boundary Estimation from Point Clouds: Algorithms, Guarantees and Applications.

We investigate identifying the boundary of a domain from sample points in the domain. We introduce new estimators for the normal vector to the boundary, distance of a point to the boundary, and a test for whether a point lies within a boundary strip. The estimators can be efficiently computed and are more accurate than the ones present in the literature. We provide rigorous error estimates for the estimators. Furthermore we use the detected boundary points to solve boundary-value problems for PDE on point clouds. We prove error estimates for the Laplace and eikonal equations on point clouds. Finally we provide a range of numerical experiments illustrating the performance of our boundary estimators, applications to PDE on point clouds, and tests on image data sets.
Clinical Research for Health Professionals: A User-Friendly Guide

HOW TO USE THIS BOOK AND OVERVIEW: The Boat Metaphor Why Research? ANATOMY AND PHYSIOLOGY: UNDERSTANDING RESEARCH CONCEPTS: Anatomy: Understanding the Research Process Questions Hypotheses Theory Designs Sampling Measurement Descriptive Statistics Inferential Statistics Tests of Significance Putting It All Together: Matching Question-Design-Analysis The Function of Research PATHOLOGY and VACCINATIONS: Mistakes with the Investigator Mistakes with the Treatment Mistakes with the Subjects Mistakes in Measurement Mistakes in Conducting Studies over Time Mistakes in Math THE EXAMINATION: FINDING MISTAKES IN STUDIES: Evaluating Research: Is It Believable? Where to Find It in a Report CLINICIANS AND GRADUATE STUDENTS: Just for Clinicians Just for Graduate Students The Future: A Final Word...or Two...or Three Appendix A: Resources Appendix B: List of Potential Biases in Research
Hexokinase binding to polypropylene test tubes. Artifactual activity losses from protein binding to disposable plastics.

Abstract In the course of our studies with rat brain hexokinase (ATP: d -hexose 6-phosphotransferase, EC 2.7.1.1), we have frequently used disposable polypropylene centrifuge tubes. As long as relatively crude systems with substantial amounts of extraneous protein were used, no difficulties were encountered. However, with more purified preparations, substantial apparent activity losses were incurred. Investigation of the situation disclosed that the reason for these apparent losses was adsorption of the hexokinase to polypropylene vessels, an unusual adsorption that appeared to be particularly effective at the air-water interface. Subsequently, we found similar effects with other enzymes. Although binding of some proteins, such as ribonuclease (1,2), to glassware has been reported, we do not know of a similar phenomenon being described for plastic ware. The increased use of disposable plastic laboratory ware necessitates an awareness of this potential problem. We present here the results of our study of the adsorption of hexokinase to polypropylene.
Fun Morality Reconsidered: Mothering and the Relational Contours of Maternal-Child Play in U.S. Working Family Life

Abstract Drawing on videotaped family interactional data, I consider Martha Wolfenstein's psychoanalytically informed conception of “fun morality” in the context of contemporary U.S. maternal–child relations. I highlight how U.S. middle-class mothers and children craft imaginative interludes that cultivate valued aspects of personhood and relationality. Cooperative, prosocial behaviors are modeled and elicited alongside individualized self-expression to constitute coexisting values in U.S. middle-class life. Analysis contributes to discussion of situated engagement in moral life by delineating how mothers take up preferred cultural models of mothering as they simultaneously mentor children's moral experiences, behaviors, and worldviews amid circumstances of daily life. [mothering, morality, children, play, family, United States]
Improved Error Bounds for a Chebysheff-Halley-Type Method

Using the majorant method we find sufficient conditions for the convergence of a Chebysheff-Halley-type method in a Banach space. Our results improve all our previous results as well as those of others.
Hunger and satiety responses to high-fat meals of varying fatty acid composition in women with obesity

Objective Determine subjective and physiological appetite responses and ad libitum intake to high-fat (HF) meals rich in either monounsaturated (MUFAs), polyunsaturated (PUFAs), or saturated fatty acids (SFAs) in women with obesity. Methods In this single-blind crossover study, three HF meals (70% of energy) rich in MUFAs, PUFAs, or SFAs in 16 women with obesity were tested. At each visit, anthropometrics and a fasting blood sample were collected. Participants then consumed one of the HF meals, and postprandial blood draws and visual analog scale (VAS) measures were collected over 5 h. An ad libitum buffet lunch was provided 5 h after the HF meal. Results Decrease in ghrelin was significantly greater for PUFA (P < 0.05) and MUFA (P < 0.01) vs. SFA while the increase in peptide YY was significantly greater for PUFA vs. both SFA and MUFA (P < 0.05). Change in glucagon-like peptide-1, VAS measurements, or total energy consumed at the buffet showed no differences between HF meals (ns). Conclusions Fatty acid composition differentially affected physiological markers of hunger and satiety. However, it was unable to show changes in subjective appetite ratings or changes in energy intake when alterations were made to fatty acid composition from an acute HF meal.
Walking the Class Action Maze: Towards a More Functional Rule 23

Over roughly the past fifteen years, the Supreme Court and lower federal courts have limited access to class actions. Many of the more restrictive decisions — such as Amchem Products, Inc. v. Windsor, Ortiz v. Fibreboard Corp., and Wal-Mart Stores, Inc. v. Dukes — are based on interpretations of Rule 23 and thus fall within the power of the Advisory Committee and rulemaking process to modify. This Article, which is a symposium contribution, proposes revisions to Rule 23 designed to deal with some of these decisions and to make the class action a more pragmatic and functional device. It focuses on two areas: (1) the constraints imposed by fairness to absentees and due process, and (2) the problem of strategic abuse associated with frivolous and weak class action filings. Responding in large part to concerns about fairness, due process, and legitimacy, the Supreme Court has adopted a vague class “cohesion” requirement (Amchem), an interpretive principle tethering the class action to outdated precedent (Ortiz), and a strong indivisibility condition for (b)(2) certification (Wal-Mart). The problem is that none of these limitations is based on a clear understanding of what fairness to absentees requires or how the individual day-in-court right can be reconciled with representative litigation. As a result, the Court’s decisions are poorly reasoned and its restrictions inadequately justified. The Advisory Committee should do what it can to correct these deficiencies, and this Article suggests a promising approach. Furthermore, in response to concerns about the strategic filing of frivolous and weak class action suits, federal judges have tightened the standard of proof for certification. But they have done so without general agreement on the normative stakes, and the result is a collection of inconsistent and relatively vague standards. The Advisory Committee should clarify the law in this area by specifying a standard of proof in the text of Rule 23. This Article suggests a useful framework for doing so. Finally, the Article briefly discusses some potential obstacles to Committee action, including the advisability of overruling recent Supreme Court decisions, potential constitutional problems, Rules Enabling Act constraints, transsubstantivity objections, and the ever-present risk of political controversy.
Viral Identification by Scanning Electron Microscopy of Preparations Stained with Fluorescein-Labeled Antibody

A new technique combines the specificity of fluorescent-antibody labeling and the resolution of the scanning electron microscope to identify and distinguish between viruses. Hemagglutination of chicken erythrocytes by influenza virus was used as a model system to demonstrate the technique.
Medicare's Chronic Care Management Program: Will It Help Primary Care Survive?

In this issue, Basu and colleagues provide a model of costs and revenue projections for Medicare's new code that will enable reimbursement for chronic care management (CCM) services. The editoriali...
Darwin vs. Wallace: When Poetry Dies and When Poetry Survives in the Not-So-Natural Selection of Memetic Evolution

The theory of memetic evolution – explaining the reproduction of cultural units called memes – illuminates the decline of poetry as a cultural presence by clarifying the contrasting attitudes towards poetry manifested by the co-discoverers of natural selection: Charles Darwin and Alfred Wallace. Darwin’s eventual indifference to poetry can be traced to an all-absorbing faith in science that extinguishes poetry-favouring memes (such as religious beliefs, memories of the ‘useless’ past and reflections on inexplicable mysteries). In contrast, Wallace’s abiding passion for poetry reflects a surprising insistence on the limits of science, an insistence that protects poetry-sustaining memes.
The effect of fish size and stocking density on the weaning success of pond-cultured pikeperch Sander lucioperca L. juveniles

The effect of initial fish size (small with TL = 40.3 ± 2.3 mm and W = 0.42 ± 0.15 g, medium with TL = 56.2 ± 2.7 mm and W = 1.66 ± 0.4 g, and big with TL = 71.0 ± 3.2 mm and W = 2.95 ± 0.65 g) and stocking density of identical fish with TL = 40.3 ± 2.3 mm and W = 0.42 ± 0.15 g (1; 2; 4; 8 fish l−1) on weaning success was evaluated in pond-cultured pikeperch. The trial was divided into weaning (12 days) and post-weaning (16 days) periods. Small juveniles reached significantly higher specific growth rate (SGR = 1.6 ± 0.2 % day−1) and survival rate (S = 81.7 ± 2.7 %) and lower cannibalism (C = 3.0 ± 0.75 %) compared to medium and large juveniles (SGR = 0.3–0.5 % day−1, S = 65.3–76.5 %, C = 6.5–7.5 %) during the weaning period. The higher survival rate was found at the two higher densities (S = 72.0–79.1 %) during the weaning period. The lowest survival rate (S = 38.9 ± 2.7) was observed at the lowest fish density. Fish stocking density did not affect growth, condition, or cannibalism rate during the weaning period. Similar trends of growth, survival, and cannibalism of weaned juveniles were observed during the post-weaning period. A mass weaning trial verified experimental results showing small pikeperch juveniles to reach satisfactory growth rate (SGR = 1.4 ± 0.1 and 7.2 ± 0.2 % day−1), survival (S = 78.7 ± 3.0 % and 97.6 ± 1.0 %), and cannibalism (C = 4.0 ± 1.5 % and 2.5 ± 1.0 %) rates during the weaning and post-weaning periods. No body or fin deformities of weaned juveniles were observed.
Plasma intestinal fatty acid binding protein in neonates with necrotizing entercolitis: A pilot study

Abstract Background/Purpose: Intestinal fatty acid-binding protein (IFABP) is found within cells at the tip of the intestinal, villi, an area commonly injured when necrotizing enterocolitis (NEC) occurs. This study was undertaken to determine if measuring IFABP concentrations in the bloodstream early in the course of NEC would differentiate patients by severity before clinical findings made it clear who had stage 3 NEC and who had milder stages. Methods: Three plasma samples from newborn infants evaluated for NEC were obtained at symptom onset and after 8 and 24 hours. IFABP concentration was measured by radioimmunoassay. Infants were classified by the final and most severe stage of NEC, and IFABP levels were compared between groups at each sampling. Results: IFABP was detectable in blood samples from all 7 infants with stage 3 NEC compared with 3 of 24 with stages 1 or 2 NEC. Elevated plasma IFABP concentrations were detectable before clinical staging could be made in 5 of the 7 subjects with stage 3 NEC. Conclusion: IFABP may be a specific marker for early identification of severe NEC.
Effect of Sleep-Wake Cycle Reversal on Luteinizing Hormone Secretory Pattern in Puberty

ABSTRACT LH (luteinizing hormone) secretion in pubertal individuals has been previously reported to be augmented during nocturnal sleep. The present paper attempts to clarify the relationship of this phenomenon to sleep. Two 24-hr periods of blood sampling every 20 min were carried out in each of 4 boys who were 14–15 yr old. The first study was during a normal sleep-wake cycle while the second study was during an acute sleep-wake reversal (or, in one subject, sleep delay). Each blood sample was assayed for LH and sleep was recorded polygraphically. The control study confirmed the association of LH secretory enhancement with nocturnal sleep at puberty while the reversal proved that a rise in LH secretion is also associated with daytime sleep. LH plasma concentrations remained elevated during nocturnal waking, as opposed to daytime waking, showing that acute sleep-wake reversal does not eliminate increased LH secretion at night in pubertal subjects.
Multiple bilateral ocular metastases from malignant melanoma associated with blue nevi.

PURPOSE Malignant melanoma associated with a blue nevus is a rare diagnosis. Additionally, only a handful of cases of malignant melanoma associated with blue nevi involving the ocular structures have been reported. We report a probable case of malignant melanoma associated with a blue nevus with metastasis to multiple bilateral ocular structures. METHODS Observational case report. RESULTS We report a case of a 27-year-old man with lymph node biopsy-proven malignant melanoma as well as a separate skin biopsy of a blue nevus, who developed multiple bilateral pigmented ocular lesions on the sclera, iris, trabecular meshwork, and choroid. CONCLUSIONS Although ocular histopathologic evidence could not be obtained, our case likely represents a case of explosive widespread metastasis probably originating from a blue nevus of unknown location, which involved both eyes and adnexae.
A Multifaceted View of the Concept of Amae : Reconsidering the Indigenous Japanese Concept of Relatedness

The indigenous Japanese concept of amae has provoked interest from scholars across disciplines. Many have provided their own version of defining amae without much attempt to synthesize it into a demonstrative definition. Non-Japanese scholars have attempted to understand the concept through their own interpretations, which has often led to confusions and erroneous conclusions. The present paper analyzes the concept of amae, focusing on its everyday use with illustrative evidence to provide contextual meanings of varied amae phenomena. A multifaceted view to approach amae is introduced. The new approach proposes to consider amae in different contexts and in three developmental phases, with evidence to support that amae is, in fact, different in each category. Future amae research is discussed.
DEAD‐box proteins as RNA helicases and chaperones

DEAD-box proteins are ubiquitous in RNA-mediated processes and function by coupling cycles of ATP binding and hydrolysis to changes in affinity for single-stranded RNA. Many DEAD-box proteins use this basic mechanism as the foundation for a version of RNA helicase activity, efficiently separating the strands of short RNA duplexes in a process that involves little or no translocation. This activity, coupled with mechanisms to direct different DEAD-box proteins to their physiological substrates, allows them to promote RNA folding steps and rearrangements and to accelerate remodeling of RNA-protein complexes. This review will describe the properties of DEAD-box proteins as RNA helicases and the current understanding of how the energy from ATPase activity is used to drive the separation of RNA duplex strands. It will then describe how the basic biochemical properties allow some DEAD-box proteins to function as chaperones by promoting RNA folding reactions, with a focus on the self-splicing group I and group II intron RNAs.
Homans, reductionism, and sociology: A reappraisal

Abstract Axiomatization of Homans' exchange theory has occasioned reexamination and clarification of many chronic issues central both to Homans' theory and its empirical assessment and to sociological theory and research at large. Often debated in the critical literature on Homans' work, these issues represent complicated, perennial controversies about such problems as tautology, codification of divergent perspectives, the theory-data chasm, and causality. Far from passe, these problems have important bearings on the conduct of contemporary sociological inquiry. Reappraising one such issue, reductionism, this paper analyzes (1) the historical vicissitudes of sociology's reductionism problem, (2) Homans' role in contemporary resurgence of interest in it, (3) the meaning of his “ultimate psychological reductionism” (4) his numerous critics' misconceptions of his position and the inappropriateness of their application of reductionist labels to it, and (5) his contribution to a refined conceptualization of re...
Histologic study of chick embryos for death causation following chorioallantoic inoculation with canary pox virus

The chorioallantoic membranes and embryos of developing hen's eggs infected with a strain variant canary pox virus were examined histologically in an effort to determine the cause of death of the embryo. The presence of a markedly thickened chorioallantois, in which the ectoderm and mesoderm are principally involved, and the conspicuous simultaneous absence of specific embryo degenerative or hyperplastic changes suggest that the embryo dies of hypoxia resulting from impaired oxygen diffusion through the thickened membrane. The evidence supporting this hypothesis is discussed.
The British, The ‘Ulamâ’, and Popular Islam in the Early Anglo-Egyptian Sudan

The power of traditional popular Islam in the modern world is difficult to assess. At times, however, developments provide at least an indirect means of evaluation for specific Muslim populations. One such experience is provided by the relations of the British with the ‘Ulamâ’ in the Anglo-Egyptian Sudan during the early years of the Condominium. These relations also provide a case study of British imperial attitudes toward Islam.
A transmission electron microscopy study of polycrystalline SrCo0.8Fe0.2O3—δ creep in the diffusion-to-power law transition regime

Abstract This study is aimed at elucidating the nature of power-law creep, threshold stress and stress-induced diffusion in SrCo0.8Fe0.2O3—δ samples subjected to creep. A SrCo0.8Fe0.2O3—δ sample deformed in the transition from a diffusion to a power-law creep regime (900°C, 50 MPa and 15% strain) as well as an assintered sample were analysed by transmission electron microscopy and energydispersive X-ray spectroscopy. The dislocation structure has been found to be highly non-uniform with areas of high dislocation density confined only within a set of well-separated grains. The dislocation structure and distribution indicate that this compound deforms by cooperative grain-boundary sliding in the transition regime. In the grains that do deform by dislocation movement, deformation is achieved by slip through the screw {110}(110) system. A planar map of the composition distribution of constituent cations revealed large fluctuations in cation composition over distances of the order of 100–200nm, as well as a co...
Unraveling transposition: γδ resolvase in complex with DNA

Abstract The structure of γ δ resolvase with a 34 base pair oligonucleotide reveals an intricate and novel complex of the protein with DNA and lays the foundations for understanding transposition at the atomic level.
Effects of partial outlet obstruction on bladder-strip sensitivity to glucose deprivation: an in vitro study in the rat

Partial outlet obstruction has been shown to result in contractile and metabolic dysfunctions. Specifically, there is a greater reduction in the response to field stimulation (FS) in comparison with the responses to bethanechol and KCl, a greater reduction in the tonic response to stimulation in comparison with the phasic response, and a reduction in oxidative metabolism of glucose accompanied by an increase in the glycolytic metabolism of glucose. The specific aim of the current study was to correlate the effects of partial outlet obstruction on the contractile responses of isolated strips of bladder smooth muscle to repetitive stimulation in the presence and absence of glucose. Adult male Sprague-Dawley rats were subjected to partial outlet obstruction by the surgical placement of silk ligatures around the urethra. After 2 weeks, each rate was anesthetized, the bladder was excised, and isolated strip studies were performed. These studies demonstrated that the maximal phasic response to FS was significantly decreased in the obstructed strips as compared with controls, with no difference being noted for responses to bethanechol or KCl; the tonic responses to all forms of stimulation were significantly decreased after obstruction, with the tonic response to FS being decreased to a greater degree than were the tonic responses to bethanechol and KCl; and in the absence of glucose, the tonic responses of control strips to all forms of stimulation were reduced to a greater degree than were the phasic responses. These studies demonstrate that the tonic response to FS is extremely sensitive to fatigue induced by repetitive stimulation.
Feasibility of conventional method of extracting internal loss and internal quantum efficiency in edge-emitting quantum dot lasers

Feasibility is discussed of the conventional method of determining internal loss coefficient and internal quantum efficiency from a measured plot of the reciprocal slope efficiency versus the cavity length L in semiconductor edge-emitting quantum dot (QD) lasers. The limitations are imposed by the cavity-length-dependence of internal loss and quantum efficiency themselves. The effect of internal loss is quantitatively analyzed, which originates from the dependence of internal loss on the carrier density, with the latter being L-dependent. In short cavities, a plot of the reciprocal slope efficiency versus the cavity length can significantly deviate from a straight line; particularly, the reciprocal slope efficiency increases with reducing the cavity length in short cavities. This plot asymptotically approaches an inclined line only in long cavities. Correspondingly, only infinitely-long-cavity (no mirror loss) values of the internal loss coefficient and the internal quantum efficiency can be extracted using the standard procedure. These latter differ significantly from those in short-cavity devices, thus strongly limiting the practicality of the procedure. For L longer than several hundred microns, the limitations are strong in a single-QD-layer laser and moderate in a multiple-QD-layer laser.
Endothelium-derived Relaxing Factor and Cyclic GMP-dependent Vasorelaxation in Human Chorionic Plate Arteries

Abstract Endothelium derived relaxing factor (EDRF), now widely believed to be nitric oxide (NO), may play an important part in the control of fetoplacental vascular tone. To further explore this role we have determined the relaxation responses to exogenous NO and examined the temporal relationship between intracellular concentrations of cyclic GMP and vascular tone in isolated ring segments of human chorionic plate arteries. We have also determined the dose relations for the contractile agonists serotonin and the throm☐ane analog U46619. Lastly, we have explored the relaxation responses to a wide range of agents known to elicit EDRF release in other vascular beds. Chorionic plate arteries relaxed significantly to exogenous NO with concomitant increases in cyclic guanosine monophosphate over basal values. ED 50 s for serotonin and U46619 were 1.48 × 10 −6 m and 3.39 × 10 −8 m respectively. The ED 50 for NO derived from S-nitroso-N-acetyl-penicillamine was 1.28 × 10 −6 m . Endothelium-intact segments of chorionic plate arteries pre-contracted with either serotonin or U46619 failed to relax significantly to acetylcholine, adenosine diphosphate, A23187, bradykinin, and histamine and only minimally to substance P. We suggest that EDRF is likely to be important in the control of placental vascular tone, but that it is not possible to demonstrate its action in an unperfused experimental system.
Reverse transcriptases of retroviruses and retroelements: an evolutionary perspective

Reverse transcriptases (RT) are central to retrovirology (as the key enzymes encoded by retroviruses) as well as to evolutionary genomics (as the only unifying component for numerous types of retroelements inhabiting genomic DNA in both prokaryotes and eukaryotes). A great deal of effort has been put into understanding the evolutionary relationships between RT-containing entities, including retroviruses, retrotransposons, and reverse transcriptase-related genes such as telomerases. However, there is still no consensus on phylogenetic history of retroelements [1-3]. The recent explosion in the amounts of genome sequence data from evolutionarily diverse organisms provides us with a rich source of novel RT-related sequences, which may be regarded as evolutionary intermediates and ''missing links'' connecting seemingly unrelated groups of reverse transcriptases. Our genomic surveys of rotifers of the Class Bdelloidea and comparisons with data from other sequenced genomes provided us with a number of examples of novel RT sequences fitting this description, including both published [3-5] and unpublished findings. Structure-based alignments and comparisons of RT-associated N- and C-terminal extension domains in newly identified groups of retroelements reveal deeper evolutionary connections between different RT classes than previously uncovered by phylogenetic analyses of the core RT domain spanning the seven most highly conserved motifs. Reverse transcriptase-related genes appear to be more common than previously thought, and may have independently given rise to mobile genetic elements several times in early evolution, via subsequent association with various catalytic domains able to cleave target genomic DNA and thereby confer intragenomic mobility to retroelement-encoded RNAs.
3-epi-betulinic acid, a new triterpenoid from Picramnia pentandra

Abstract Extraction of the bark of Picramnia pentandra Sw. gave as the main component a new triterpenoid, whose structure was established as 3-epi-betulinic acid.
Long-time behavior of a nuclear reactor

A fundamental problem of reactor physics is the determination of the long-time behavior of the neutron population in a nuclear reactor. In particular, one is interested in the question whether the total neutron density has a purely exponential behavior as t → ∞. We formulate this problem as an abstract Cauchy problem, show that the solution is given by a semigroup, and investigate the asymptotic behavior of the semigroup.
Comparative study of frequency agile data transmission schemes for cognitive radio transceivers

In this paper, we present a comparative study of two frequency agile data transmission schemes employed by cognitive radio transceivers for use in dynamic spectrum access (DSA) networks. The transmission schemes under study, non-contiguous orthogonal frequency division multiplexing (NC-OFDM) and a modified form of multicarrier code division multiple access (MC-CDMA), are based on conventional OFDM and MC-CDMA schemes. Besides providing a degree of error robustness while yielding large data throughputs, the schemes under study are designed to avoid interference with incumbent user transmissions via subcarrier deactivation, i.e., nulling, in order to operate within a DSA network. Although several studies comparing conventional OFDM and MC-CDMA have been conducted in the literature, and the relative performance of NC-OFDM and the variant of MC-CDMA schemes is intuitive, there has not been a quantitative performance evaluation of these schemes when used within a DSA network. The quantitative evaluation corroborates with the intuitive assessment that NC-OFDM exhibits a greater degree of error robustness when avoiding incumbent transmissions relative to the variant of MC-CDMA.
Cutting efficiency of endodontic reamers.

Abstract The cutting efficiency of endodontic reamers was evaluated with a testing apparatus developed especially for the study. Bovine bone was used to simulate dentin because of its structural and chemical similarity to dentin. Triangular reamers cut more efficiently than did square reamers, but had a higher failure rate. Instrument failure resulted from deformation or fracture of the blade rather than from wear. Commercially available instruments exhibitd wide variations in quality, sharpness of cutting edges, cross-sectional configuration, and number of flutes.
UAS Collision Avoidance Algorithm Minimizing Impact on Route Surveillance

A collision avoidance algorithm is developed and implemented that is applicable to many different unmanned aerial systems ranging from a single platform with the ability to perform all collision avoidance functions independently to multiple vehicles performing functions as a cooperative group with collision avoidance commands computed at a ground station. The algorithm leverages advances in several theoretical fields including robotics, homing guidance, and airspace management, and considers several approaches to conflict detection and resolution including the collision cone approach. The collision avoidance system is exercised and tested using operational hardware and platforms. Novel developments using an aggregated collision cone approach allows each unmanned aircraft to detect and avoid collisions with two or more other aircraft simultaneously. The collision avoidance system is implemented using a miniature unmanned aircraft with an onboard autopilot. Various simulation and flight test cases are used to demonstrate the algorithm’s robustness to different collision encounters at various engagement angles. The flight test results are compared with ideal, software-in-the-loop, and hardware-in-the-loop tests. The results presented are the first known flight tests of a global, three-dimensional, geometric collision avoidance system on an unmanned aircraft system.
Polarized laser-induced photofragmentation studies of JKM-selected CH3I molecules: retention of orientation in optical and DC electric fields

The technique of linearly polarized laser-induced photofragmentation for the measurement of the degree of orientation of rotationally state-selected symmetric top molecules [Phys. Rev. Lett.59, 2951 (1987)] has been used to study the retention of molecular orientation in optical frequency AC and homogeneous DC electric fields. For CH3I beams, state-selected by the electrostatic hexapole focuser in several specific low-J parent states, recoupling of the iodine nuclear spin with the molecular rotational angular momentum occurs rapidly in weak fields, leading to some loss of orientation, but the resulting degree of orientation (i.e., theM F distribution) is retained in both DC and optical frequency electric fields. The direction of the orientation of the molecular axis can be inverted with 100% efficiency by changing the sign of the DC ‘orienting field’. The up/down asymmetry of the photofragment angular distribution can be observed with either parallel (vertical) or perpendicular (horizontal) laser polarization.
THE TRUTH-IN-MENU LAW AND RESTAURANT CONSUMERS

This study uses nutrition and descriptive claim information factors covered by the Nutrition Labeling and Education Act (NLEA), the “Truth-in-Menu” law, to have consumers identify which factors are most important when choosing restaurant menu items. The results show server knowledge of menu items is the most important factor for survey respondents followed by the visual presentation. Restaurateurs use the Truth-in-Menu law to ensure that the information provided about menu items is accurate and conforms to the federal regulations set forth by the NLEA.
Manipulating and Quantifying the Compositional Heterogeneity in Sol−Gel Processed K(Ta1-xNbx)O3

A series of K(TaxNb1-x)O3 (KTN) samples were prepared by two different sol−gel processes and by the reaction of mixed oxides. The local and long-range structures of the sol−gel-processed materials were examined as a function of heat treatment using a combination of powder diffraction and EXAFS studies. The compositional homogeneity of the perovskite solid solution products was also examined by EXAFS. The local structures around both the niobium and tantalum in the sol−gel-processed samples change on heating prior to crystallization. EXAFS provided evidence for the existence of Ta−O−Nb links in the dry KTN gels. The data for the perovskite KTN samples prepared using a conventional alkoxide sol−gel route are consistent with a random distribution of tantalum and niobium in the solid solution. However, the materials prepared by the direct reaction of mixed oxides were highly inhomogeneous, even after several regrinding and heating cycles. An alternative sol−gel method that employed prehydrolyzed precursors wa...
MISSING RELATIVITY TERMS IN GPS

The current GPS relativity corrections were derived by a committee of experts chosen by the Air Force. The original derivation assumed that the GPS reference frame is inertial, with its origin at the center of the earth. It also assumed that the user obtains inertial GPS coordinate time from the satellites. A new approach in relativity is taken to determine the relativity effects for both GPS satellites and GPS receivers. To the first-order approximation, there are no new relativity effects missing in the GPS algorithm if one converts all observations to the earth-centered inertial (ECI) frame and the GPS inertial coordinate time. However, there are some uncompensated effects required to make the complete transformation from the noninertial frame of a GPS receiver to the inertial frame of GPS. These effects and their magnitudes are examined in this paper.
Beyond managerial opportunism: Supplier power and managerial compliance in a franchised marketing channel

Abstract A groundbreaking contribution to transaction cost analysis was advanced by John (1984) who recognized that managerial opportunism is a behavioral variable requiring theoretical explanation, not an exogenous constraints to be assumed and imposed upon the marketing channel network. However, it is argued that several features of John's final model predicting opportunism seem problematic. An alternative model, one that explains supplier power and managerial opportunism-the latter being viewed as an aspect of the broader and more common social psychological construct of compliance-is proposed and operationalized using John's (1984) indicator measures. Then, using John's (1984) published data, this model is subjected to statistical testing and modification through analysis of covariance structures. Results suggest that the proposed model is superior to John's with respect to goodness-of-fit and other important modeling criteria. Conclusions, managerial implications, study limitations, and directions for future research are discussed. j busn res 1994. 30.211–223
Correlating substituent parameter values to electron transport properties of molecules

Abstract There are a vast number of organic compounds that could be considered for use in molecular electronics. Because of this, the need for efficient and economical screening tools has emerged. We demonstrate that the substituent parameter values ( σ ), commonly found in advanced organic chemistry textbooks, correlate strongly with features of the charge migration process, establishing them as useful indicators of electronic properties. Specifically, we report that ab initio derived electronic charge transfer values for 16 different substituted aromatic molecules for molecular junctions correlate to the σ values with a correlation coefficient squared ( R 2 ) of 0.863.
Porphyrin distributions in crude oils from the Jianghan and Biyang basins, China

Abstract A number of oils, tar sands and extracts of suspected source rocks from the Jianghan and Biyang basins of China have been studied to investigate their porphyrin content. The results obtained suggest that these distributions are controlled to a large extent by the nature of the depositional environment and the maturity levels of the sediments. It is proposed that the predominance of Ni porphyrins in the sediments of these basins is caused mainly by the high Ni content of the groundwater. The relatively high content of a C32 porphyrin isomer with a five-membered ring with a methyl substituent, is indicative of environments with very high salinity. The porphyrin distributions have been affected through thermal maturation with the major changes being dealkylation/alkylation within ETIO porphyrins. The instability of Ni-DPEP porphyrins is suggested as a major reason for the rarity of DPEP porphyrins in Chinese oils. The ratios of DPEP/ETIO (or % DPEP ETIO + DPEP ), C 31 ETIO-A C 28 ETIO-B and ETIO-A C 31 C 30 are useful as thermal maturity parameters and the results also indicate that the percentage of DPEP porphyrins decreases through migration.
Application of high performing system theory to corporate venture teams

The purpose of this presentation is to examine the potential application of Peter Vaill's concept of high performing systems (“ThePurposing of High Performing Systems,” Organizational Dynamics, Autumn 1982) to corporate venture team management. Vaill argues that high performing human systems (HPS) contain three major qualities, namely, the ability to focus on the key success levers of an organization, feelings (personal commitment), and the investment of time/ personal continuing presence. In this presentation high performing human systems will be explored with emphasis on their major characteristics. Special attention also will be focused on strengths and limits of HPS. The consequences to performance and the system's participants are explored when one or more of the three major components (focus, time, or feelings) are absent. The presentation then addresses corporate venture teams and how they function within their larger host organizations. We then posit how Vaill's concept of high performing systems can be used in managing and assessing corporate venture teams. Implications for sponsors of venture teams are discussed as well as areas for future research.
On spatiotemporal patchiness and the coexistence of five species of Chronogaster (Nematoda: Chronogasteridae) in a riparian wetland

Spatiotemporal patchiness in the soil environment is thought to be crucial for the maintenance of soil biodiversity. It provides diverse microhabitats (allowing resource partitioning), and presents these in a complex mosaic, such that competitors may be spatially and temporally separated (promoting patch dynamics). The objective of our study was to assess the importance of patch dynamics for the maintenance of landscape-level nematode diversity. The spatiotemporal aggregation patterns in populations of five species of the bacterivorous genus Chronogaster were analyzed for a 0.7-ha riparian wetland, during four seasons, using geostatistical methods (spatiotemporal variograms, cross-correlograms, and log-normal kriging). We found that for the three most abundant species, aggregation was significant over distances of 13–39 m, with intraspecific aggregation stronger than interspecific aggregation. In addition, species patterns appeared to be temporally dynamic: local population declines alternated with local blooms at different sites and seasons. One species was consistently present at the same few sites, but the other species showed gradual temporal decreases and increases at different locations in the wetland. Combining nematode patterns with information on soil resource distributions and Chronogaster ecology, indicated that both soil resource patchiness and repeated, but largely unpredictable, disturbances caused by local soil moisture fluctuations could promote landscape-level Chronogaster diversity by providing ample 'probability refuges.' Local species populations, reduced by competition, predation and drought, could recolonize patches either through the awakening of local dormant 'seed populations,' or through limited passive dispersal by wind, water, and phoresis. We suggest that the spatiotemporal Chronogaster data provide preliminary evidence for the importance of patch dynamics in maintaining soil nematode diversity.