cssi/SciSciGPT-SciSciNet huggingface dataset:
Interfacial Layer - A New Mechanism for Electromechanical Response

Electric field induced phase transition has been used to explain the high strain response in some PVDF-based EAP. However, it is hard to understand some features (such as the relationship between the strain and the preload) of elastomers - an important type of EAPs. In this paper, we reported the study of recrystallization on high-energy-electron irradiated P(VDF-TrFE) copolymer. The morphology and structure as well as the structural transformation in the recrystallized copolymers were studied by means of X-ray diffraction, DSC, FTIR, and polarization measurements. The effect of crosslinking induced by the irradiation is discussed. The results suggest that a new interface layer existed in the recrystallized polymers. The partially ordered interfacial layer is a novel micro-origin of a high polarization obtained in an EAP. Based on this concept, the effect of preload on the E-M performance of the elastomers can be well explained. A new method to develop high performance electroactive polymer is outlined by using the interface state.
Precipitation retention and soil erosion under varying climate, land use, and tillage and cropping systems

ABSTRACT: Nonirrigated crop yields and forage production are limited by low and variable precipitation in the southern Great Plains. Precipitation variation involves production risks, which can be reduced by considering probability of precipitation, precipitation retention, and soil erosion under various production systems. The objective of this study was to probabilistically quantify the impact of precipitation variations, land use, cropping, and tillage systems on precipitation retention and soil erosion. Five 1.6 ha watersheds that had 3 to 4 percent slopes, and similar silt loam soils were selected. One was kept in native grass, and the others were planted into winter wheat (Triticum aestivum L.) under different cropping and tillage systems. Daily runoff and soil erosion were measured at the outlet of each watershed. Precipitation distributions exhibited great seasonal and interannual variations, and precipitation retention distributions resembled those of precipitation. Cropping and tillage systems affected precipitation retention but much less than did precipitation variations. Available soil water storage, which was largely controlled by ET, played an important role in retaining precipitation. This indicates that cropping systems should be adjusted to precipitation patterns, if predictable, for better soil water use. Land use and cropping and tillage systems had a much greater impact on soil erosion than on precipitation retention. Soil erosion risks, which were proportional to the levels of tillage disturbance, were mainly caused by a few large storms in summer, when surface cover was low. This study explored a novel approach for evaluating production risks associated with insufficient precipitation retention and excessive soil erosion for certain crops or cropping systems under assumed precipitation conditions.
OBSERVATIONS OF THE ION PILE-UP IN COMETS HALE-BOPP AND HYAKUTAKE

High resolution long-slit spectra of Comet Hale–Bopp (C/1995 O1) were obtained with the Hamilton Echelle Spectrograph of Lick Observatory in March and April 1997. H_2O^+ column density profiles derived from these spectra imply the existence of a shell of enhanced plasma density surrounding the nucleus on its sunward side at a radius of (1.03±0.12)×10^5 km. We propose that this is the ion pile-up detected at 1.1×10^4 km sunward of the nucleus of Comet Halley (1P/1682 Q1) by both the Giotto and Vega 1 spacecraft. Long-slit H_2O^+ spectra of Comet Hyakutake (C/1996 B2) indicate the presence of a similar ion pile-up at a radial distance of greater than 1.6×10^4 km from the nucleus. These observations suggest that the ion pile-up is a typical feature of the near-nuclear plasma environment of active comets. The standoff distance and width of the high density region roughly scale with the gas production rate of the comet but the exact functional dependence, which could be used to constrain the mechanism of pile-up formation, remains unclear.
User Satisfaction with Computerized Order Entry System and Its Effect on Workplace Level of Stress

To evaluate the impact of Computerized Provider Order Entry (CPOE) on workplace stress and overall job performance, as perceived by medical students, housestaff, attending physicians and nurses, after CPOE implementation at Penn State--Milton S. Hershey Medical Center, an academic tertiary care facility, in 2005. Using an online survey, the authors studied attitudes towards CPOE among 862 health care professionals. The main outcome measures were job performance and perceived stress levels. Statistical analyses were conducted using the Statistical Analytical Software (SAS Inc, Carey, NC). A total of 413 respondents completed the entire survey (47.9 % response rate). Respondents in the younger age group were more familiar with the system, used it more frequently, and were more satisfied with it. Interns and residents were the most satisfied groups with the system, while attending physicians expressed the least satisfaction. Attending physicians and fellows found the system least user friendly compared with other groups, and also tended to express more stress and frustration with the system. Participants with previous CPOE experience were more familiar with the system, would use the system more frequently and were more likely to perceive the system as user friendly. User satisfaction with CPOE increases by familiarity and frequent use of the system. Improvement in system characteristics and avoidance of confusing terminology and inconsistent display of data is expected to enhance user satisfaction. Training in the use of CPOE should start early, ideally integrated into medical and nursing school curricula and form a continuous, long-term and user-specific process. This is expected to increase familiarity with the system, reducing stress and leading to improved user satisfaction and to subsequent enhanced safety and efficiency.
Non-Hodgkin lymphoma in skeletal muscle manifesting as homogeneous masses with CT attenuation similar to muscle

Two cases are presented of masses in muscle due to non-Hodgkin lymphoma (NHL) that were homogeneous and isoattenuating to normal muscle on CT. In each case, the mass was clinically suspected of representing soft tissue sarcoma. However, the masses were relatively inapparent on CT, being visible predominantly as mass effect – an appearance unlike that of soft tissue sarcomas. It is important to be aware that NHL in muscle can be difficult to detect at CT, even with intravenous contrast enhancement; therefore, a clinically apparent mass should not be dismissed on the basis of an apparently unremarkable CT scan of the region. Such findings should suggest the diagnosis of NHL rather than sarcoma.
Finite-range time delays in numerical attosecond-streaking experiments

We present results of numerical simulations and theoretical classical analysis of time delays with respect to the instant of ionization in a numerical streaking experiment. We show that the time delay is related to a finite range in space, which the emitted electron probes after its transition into the continuum until the streaking pulse ceases. This finite-range time delay results from the coupling of the atomic potential and the streaking field and strongly depends on the parameters, in particular the duration, of the streaking field. It can be represented as an integral or sum over piecewise field-free time delays weighted by the ratio of the instantaneous streaking field strength relative to the field strength at the instant of ionization.
Epigenetic regulatory mechanisms during preimplantation development.

Following fertilization, the newly formed zygote faces several critical decisions regarding cell fate and lineage commitment. First, the parental genomes must be reprogrammed and reset for the zygotic genome to assume responsibility for gene expression. Second, blastomeres must be committed to form either the inner cell mass or trophectoderm before implantation. A variety of epigenetic mechanisms underlies each of these steps, allowing for proper activation of transcriptional circuits which function to specify a cell's identity and maintain or adjust that state as developmental and environmental conditions dictate. These epigenetic mechanisms encompass DNA methylation, post-translational histone modification, chromatin remodeling, and alterations in nuclear architecture. In recent years, stem cells derived from the inner cell mass have been used to examine the epigenetic pathways that regulate pluripotency, differentiation, and lineage commitment. From a technical standpoint, embryonic stem cells provide an easier system to work with compared to preimplantation embryos; however, it is currently unknown how closely the epigenetic mechanisms of cultured stem cells resemble their counterparts in the intact embryo. Furthermore, it remains unclear how similar the reprogramming pathways in artificially created systems, such as nuclear transfer-derived embryos and induced pluripotent stem cells, are to those in naturally created embryos. In this review, we summarize the current knowledge of epigenetic influences during preimplantation development and shed light on the extent to which these pathways are conserved in cultured pluripotent cells in vitro. In doing so, we demonstrate the critical role that epigenetic mechanisms play in the establishment of cell fate during the earliest stages of mammalian development. Birth Defects Research (Part C) 87:297–313, 2009. © 2009 Wiley-Liss, Inc.
Kaufman approach calculations of partial phase diagrams amongst Th, U, Np and Pu

Abstract The Kaufman approach has been applied to the calculation of the liquid plus bcc portion of binary phase diagrams amongst the elements Th, U, Pu, and Np. Reasonable agreement between calculated and experimentally determined phase boundaries has been achieved in systems not involving Th. The discrepancies exhibited by systems involving Th have been attributed to the large difference in the valence and the size of the participating atomic species.
Application of the Ti-in-quartz thermobarometer to rutile-free systems. Reply to: a comment on: ‘TitaniQ under pressure: the effect of pressure and temperature on the solubility of Ti in quartz’ by Thomas et al.

The premise of the Wilson et al. comment is that the Ti-in-quartz solubility calibration (Thomas et al. in Contrib Mineral Petrol 160:743–759, 2010) is fundamentally flawed. They reach this conclusion because P–T estimates using the Ti-in-quartz calibration differ from their previous interpretations for crystallization conditions of the Bishop and Oruanui rhyolites. If correct, this assertion has far-reaching implications, so a careful assessment of the Wilson et al. reasoning is warranted. Application of the Ti-in-quartz calibration as a thermobarometer in rutile-free rocks requires an estimation of TiO2 activity in the liquid (\( a_{{{\text{TiO}}_{ 2} }} \) (liquid–rutile); referenced to rutile saturation) and an independent constraint on either P or T to obtain the crystallization temperature or pressure, respectively. The foundation of Wilson et al.’s argument is that temperature estimates obtained from Fe–Ti oxide thermometry accurately reflect crystallization conditions of quartz in the two rhyolites discussed. We maintain that our experimental approach is sound, the thermodynamic basis of the Ti-in-quartz calibration is fundamentally correct, and our experimental results are robust and reproducible. We suggest that the reason Wilson et al. obtain implausible pressure estimates is because estimates for T and \( a_{{{\text{TiO}}_{ 2} }} \) they used as input values for the Ti-in-quartz calibration are demonstrably too high. Numerous studies show that Fe–Ti oxide temperature estimates of some rhyolites are substantially higher than those predicted by well-constrained phase equilibria. In this reply, we show that when reasonable input values for T and \( a_{{{\text{TiO}}_{ 2} }} \) (liquid–rutile) are used, pressure estimates obtained from the Ti-in-quartz calibration are well aligned with phase equilibria and essentially identical to melt inclusion volatile saturation pressures.
Simulation and testing of digital control on a flexible beam

Large space structures are expected to have control problems due to low stiffness and damping, and control laws for these structures must deal with shape and configuration control as well as attitude and orbit maintenance. In general, these control tasks must be accomplished without adversely interacting with the lightly damped and low frequency vibration modes of the structure. Modal control schemes have been proposed to deal with these problems. A discrete time parameter adaptive control scheme which uses modal control has been proposed by Montgomery and Johnson (1978). In the present investigation the method considered by Montgomery and Johnson is applied to a homogeneous free-free beam in both numerical simulation and laboratory experimentation. Mathematical modeling of the beam is treated in a manner expedient for digital simulation and control implementation.
Aspects of Fokker-Planck transport

We apply to a simple example, taken from neutron thermalization, techniques we have been using in the study of Fokker-Planck transport of test particles. The example from neutron physics concerns the divergence of the series expressing diffusion length as a function of absorber concentration. In both cases, analytic continuation, and matched asymptotic expansion play a role.
Development of a genomic site for gene integration and expression in Enterococcus faecalis

Enterococcus faecalis, a gram-positive opportunistic pathogen, has become one of the leading causes of nosocomial infections. Normally a resident of the gastrointestinal tract, extensive use of antibiotics has resulted in the rise of E. faecalis strains that are resistant to multiple antibiotics. This, compounded with the ability to easily exchange antibiotic determinants with other bacteria, has made certain E. faecalis infections difficult to treat medically. The genetic toolbox for the study of E. faecalis has expanded greatly in recent years, but has lacked methodology to stably introduce a gene in single copy in a non-disruptive manner for complementation or expression of non-native genes. In this study, we identified a specific site in the genome of E. faecalis OG1RF that can serve as an expression site for a gene of interest. This site is well conserved in most of the sequenced E. faecalis genomes. A vector has also been developed to integrate genes into this site by allelic exchange. Using this system, we complemented an in-frame deletion in eutV, demonstrating that the mutation does not cause polar effects. We also generated an E. faecalis OG1RF strain that stably expresses the green fluorescent protein and is comparable to the parent strain in terms of in vitro growth and pathogenicity in C. elegans and mice. Another major advantage of this new methodology is the ability to express integrated genes without the need for maintaining antibiotic selection, making this an ideal tool for functional studies of genes in infection models and co-culture systems.
The mammalian toxicity of dicyclopentadiene

Abstract Dicyclopentadiene [3a,4,7,7a-Tetrahydro-4,7-methanoindene] is slightly to moderately toxic by the dermal route and highly toxic by the oral route in single-dose studies. The LC50 values for single 4-hr vapor inhalation periods varied from 771 ppm for male rabbits to 145 ppm for male mice. Human sensory response studies revealed that the vapor has very good warning properties as it was detected at 0.003 ppm. The response of rats and dogs to repeated 7-hr exposures of dicyclopentadiene vapor for 89 days suggests that man should not be allowed to inhale more than 5 ppm during an 8-hr working day, 5 days per wk. It should be emphasized that this “hygienic standard” is an estimate based on experimental data and therefore is subject to modification as information is gathered on human experience.
Orderings on semirings

Though more general definitions are sometimes used, for this paper a semiring will be defined to be a set S with two operations + (addition) and �9 (multiplication); with respect to addition, S is a commutative monoid with 0 as its identity dement�9 With respect to multiplication, S is a (generaily noncommutative) monoid with 1 as its identity element. Connecting the two algebraic structures are the distributive laws, a.(b+ c) = a.b+ a.c and (a+ b).c = a.c+ b.c for all a,b,c E S, and the requirement a.0 = 0.a = 0 for every a C S. The reader is referred to [3] and [4] for an introduction to the theory of semirings. Semirings have proven to be useful in theoretical computer science, in particular for studying automata and formal languages. Several authors have considered total order relations on semirings (e.g. [8, 9]). In this paper, we begin by looking at special classes of semirings which arise naturally in the theory of formally real (not necessarily commutative) fields and in the study of (commutative) real algebraic geometry�9 In the second section of the paper, we give characterizations of the semirings which arise in this way. Using this work as motivation, the third section of the paper suggests a new notion of ordering for commutative semirings which generalizes the concepts found in real algebraic geometry. In the most general case, these orderings turn out to have a somewhat weaker connection with total order relations than in the case of rings.
Anaesthetic considerations in patients with mitral valve prolapse

Summary Mitral valve prolapse (MVP), reported as occurring in up to 17% of healthy individuals, is considered to be the commonest cardiac valvular abnormality. Although the anaesthetic course may be uneventful, complications may arise for the first time in the peri-operative period and include life threatening dysrhythmias, mitral regurgitation and infective endocarditis. Anaesthetic management of three of the seven patients with MVP treated at our institution over a 12-month period is discussed and the lilerature reviewed.
Physical studies of rabbit muscle phosphofructokinase: sedimentation behavior of the enzymatic reactive form.

Abstract Reacting enzyme sedimentation experiments were carried out to identify the active form of rabbit muscle phosphofructokinase in glycylglycine buffer at pH 8.55 and 23 ± 1 °C. Results from these experiments reveal one active form with s20,w = 12.2 ± 0.3 and 12.2 ± 0.3 S in a coupled enzyme and a pH-dependent dye linked system, respectively.
The Pluralistic Universe of Law: Towards a Neo-Classical Legal Pragmatism*

After a brief sketch of the history of philosophical pragmatism generally, and of legal pragmatism specifically (section 1), this paper develops a new, neo-classical legal pragmatism: a theory of law drawing in part on Holmes, but also on ideas from the classical pragmatist tradition in philosophy. Main themes are the “pluralistic universe” of law (section 2); the evolution of legal systems (section 3); the place of logic in the law (section 4); and the relation of law and morality (section 5).
A corticotropin (ACTH) related peptide with cytotoxic activity

A commercially available preparation of corticotropin was found to have potent cytotoxic activity for several established cell lines. Neither synthetic corticotropin nor alpha melanocyte stimulating hormone demonstrated this cytotoxic activity. Gel filtration allowed separation of a 2100 dalton cytotoxic peptide from the actual corticotropin present in the commercially prepared material. The structural relatedness of the cytotoxic peptide to corticotropin was demonstrated by neutralization with antisera to alpha melanocyte stimulating hormone. These studies indicate the existence of a newly identified ACTH related peptide with cytotoxic activity.
Triassic fungi with suggested affinities to the Endogonales (Zygomycotina)

Abstract Fruiting structures of several fungi are described from permineralized peat deposits of Triasic age. Specimens appear to be spores and sporangia of members of the extant order Endogonales (Zygomycotina). Large spherical spores resembling chlamydospores of Glomus , zygospores of Endogone and possible sporangia are reported. It is evident that many fossil Endogonaceae were saprophytes. We suggest that this family contained members which were important terrestrial saprophytes in the Paleozoic and Mesozoic, but may have been replaced in that niche by more successful ascomycetes during the Cenozoic.
Structural contributions to fibrillatory rotors in a patient-derived computational model of the atria.

Aims The aim of this study was to investigate structural contributions to the maintenance of rotors in human atrial fibrillation (AF) and possible mechanisms of termination. Methods and results A three-dimensional human biatrial finite element model based on patient-derived computed tomography and arrhythmia observed at electrophysiology study was used to study AF. With normal physiological electrical conductivity and effective refractory periods (ERPs), wave break failed to sustain reentrant activity or electrical rotors. With depressed excitability, decreased conduction anisotropy, and shorter ERP characteristic of AF, reentrant rotors were readily maintained. Rotors were transiently or permanently trapped by fibre discontinuities on the lateral wall of the right atrium near the tricuspid valve orifice and adjacent to the crista terminalis, both known sites of right atrial arrhythmias. Modelling inexcitable regions near the rotor tip to simulate fibrosis anchored the rotors, converting the arrhythmia to macro-reentry. Accordingly, increasing the spatial core of inexcitable tissue decreased the frequency of rotation, widened the excitable gap, and enabled an external wave to impinge on the rotor core and displace the source. Conclusion These model findings highlight the importance of structural features in rotor dynamics and suggest that regions of fibrosis may anchor fibrillatory rotors. Increasing extent of fibrosis and scar may eventually convert fibrillation to excitable gap reentry. Such macro-reentry can then be eliminated by extending the obstacle or by external stimuli that penetrate the excitable gap.
Predicting the fate of artefacts in energetic, shallow marine environments : an approach to site management

A poor understanding of the physical environment often hinders management of marine artefacts. A study was conducted of an early-18th-century shipwreck to test whether the wreckage could have settled through ∼3.5 m of substrate. Results indicate that the wreck could have settled via episodic scour processes driven by storms and tidal inlet migration. A numerical model, modified to include characteristics of the underlying geology, predicts continued scour under moderate waves. Scour processes appear to have been interrupted by an erosion-resistant underlying layer, so that the wreck now remains exposed, subject to degradation. A generalized approach to predict burial or exposure of other shallow-water artefacts is developed. © 2006 The Authors
Male facial masculinity influences attributions of personality and reproductive strategy

Facial masculinity may be used as a cue in female mate choice, as it reflects the success of the male genotype in its developmental environment. Women may maximize reproductive success by using a conditional strategy favoring highly masculine facial features for short-term relationships and feminized facial features in men for long-term relationships. Three studies examine reactions to masculinized and feminized male facial composites. Properties of the original composite image affect ratings of critical attributes and the magnitude of the differences in ratings between versions undergoing identical processes of geometric manipulation (Study 1). Both men and women attribute personality, behavior, and mating strategies consistent with predictions derived from the good genes and mating trade-off hypotheses (Study 2). Participants accurately grouped behavioral tendencies related to high mating effort/risky strategies and high parenting effort/risk adverse strategies and associated mating effort more so with masculinized faces and parenting effort more so with feminized faces (Study 3). These results indicate that male facial masculinity serves as a visual cue for inferring personality and reproductive strategy. Male facial masculinity may be used as a cue in female mate choice, as it reflects the success of the male genotype in the developmental environment. Men exhibiting these features may have a greater rate of return from mating effort compared to other men and thus may allocate more effort toward mating and less to parental investment. Women may maximize their reproductive success by showing stronger preferences for partners with highly masculine faces for short-term sexual relationships but favor less masculinized faces in prospective long-term relationship partners. Three studies examine whether facial masculinity is related to attributions of male reproductive strategy and contingent female mating strategies.
The Specificity of 130-kDa Leech Sensory Afferent Proteins Is Encoded by Their Carbohydrate Epitopes

From early development through adulthood in the leech, sensory afferents, glial cells, and connective tissue express different epitopes located on a group of 130-kDa glycoproteins. The sensory epitope [reactive with monoclonal antibody (mAb) Lan3-2] is shared by the peripheral sensory afferents of different sensory modalities. In contrast, three other immunocytochemically distinct epitopes (reactive with mAbs Laz2-369, Laz7-79, and Laz6-212) differentiate these sensory afferents according to their sensory modalities. The glial epitope (mAb Laz6-297) is expressed on all macroglial processes, and the connective tissue epitope (mAb Laz9-84) is located on connective tissue surrounding the CNS, as well as in the peripheral tissues. The hydrophilic-hydrophobic nature of the 130-kDa sensory afferent and glial proteins was determined by phase separation with Triton X-114 and hypoosmotic extraction. They behave as peripheral membrane proteins. Deglycosylation of 130-kDa glycoproteins with N-Glycanase or preincubation of their respective mAbs with alpha-methylmannoside showed that the sensory epitope contains mannose, whereas the modality epitopes are of an undefined carbohydrate character. Immunoprecipitation and a peptide mapping experiment confirmed the existence of four distinct sensory afferent epitopes. Previous studies provided evidence that the mannose-containing Lan3-2 epitope mediates normal sensory afferent growth in the synaptic neuropile. We, therefore, postulate that the carbohydrate epitopes on sensory afferent glycoproteins participate in synapse formation.
Vascular endothelial growth factor-induced in vitro angiogenesis and plasminogen activator expression are dependent on endogenous basic fibroblast growth factor

Induction of in vitro angiogenesis and upregulation of urokinase- and tissue type-plasminogen activator (uPA, tPA) expression are two hallmarks of vascular endothelial growth factor (VEGF) activity on cultured endothelial cells. We report here that neutralizing antibodies to basic fibroblast growth factor (bFGF) inhibit VEGF-induced in vitro angiogenesis in bovine microvascular endothelial (BME) cells. Analysis of VEGF receptor-2 (VEGFR-2) expression revealed no alteration in VEGFR-2 mRNA or total protein in anti-bFGF antibody-treated BME or bovine aortic endothelial (BAE) cells. Ethidium bromide/agarose gel electrophoresis on the cytosolic fraction of BME cells revealed a basal level of fragmented DNA that was increased by anti-bFGF antibodies to an extent not exceeding that observed in parallel cultures incubated with concentrations of transforming growth factor-ss1 that increase VEGF-induced in vitro angiogenesis. In both BME and BAE cells, antibodies to bFGF also decreased basal levels of cell-associated uPA activity, and completely blocked the VEGF-mediated increase in uPA and tPA expression observed in parallel cultures incubated with VEGF alone. In contrast, PA inhibitor-1 expression was strongly upregulated in BME and BAE cells incubated with antibodies to bFGF, either alone or in combination with VEGF. These findings demonstrate that: (1) VEGF-induced in vitro angiogenesis and PA expression are dependent on endogenous bFGF, (2) that this phenomenon is not mediated by a decrease in VEGFR-2 expression and that apoptosis does not necessarily correlate with inhibition of invasion, and (3) that inhibition of endogenous bFGF in VEGF-treated cells results in a net antiproteolytic (and possibly also anti-adherent) effect, which could account in part for the inhibitory effect of the anti-bFGF antibodies. These findings point to a novel and unsuspected role for endogenous bFGF in regulating VEGF-induced in vitro angiogenesis.
Applications of quorum sensing in biotechnology.

Many unicellular microorganisms use small signaling molecules to determine their local concentration. The processes involved in the production and recognition of these signals are collectively known as quorum sensing (QS). This form of cell–cell communication is used by unicellular microorganisms to co-ordinate their activities, which allows them to function as multi-cellular systems. Recently, several groups have demonstrated artificial intra-species and inter-species communication through synthetic circuits which incorporate components of bacterial QS systems. Engineered QS-based circuits have a wide range of applications such as production of biochemicals, tissue engineering, and mixed-species fermentations. They are also highly useful in designing microbial biosensors to identify bacterial species present in the environment and within living organisms. In this review, we first provide an overview of bacterial QS systems and the mechanisms developed by bacteria and higher organisms to obstruct QS communications. Next, we describe the different ways in which researchers have designed QS-based circuits and their applications in biotechnology. Finally, disruption of quorum sensing is discussed as a viable strategy for preventing the formation of harmful biofilms in membrane bioreactors and marine transportation.
Dynamic on-line task scheduling on parallel processors

Abstract The problem of scheduling on-line a stream of multi-tasked jobs on a set of parallel processors is considered. The goal is to minimize the average sojourn time experienced by each individual job in the system. The arriving jobs are comprised of parallel applications, each consisting of multiple independent tasks that are instantaneously assigned to processor queues upon its arrival to the system. The processors independently and concurrently service the tasks in their local queues which are first-come-first-served (FCFS). A job can depart from the system only when all its tasks have been executed and reassembled into the original single-job structure; until then, completed tasks are placed in a reassembly queue. All tasks have i.i.d. memoryless exponential service times and any task can be processed by any processor. Migration of tasks between queues — after their initial allocation — is not allowed. This model captures the main features of multiprocessor computer systems executing parallel programs. The key scheduling issue is as follows. When some queue backlogs are small, an incoming job should spread its tasks to those lightly loaded queues in order to take advantage of the parallel processing gain and lower its processing delay. On the other hand, when all queues are fairly congested, the job should schedule all its tasks sequentially in a single queue to avoid excessive reassembly delay (due to backlog fluctuations) and lower its task synchronization delay. In this paper, the trade-off between these two objectives is quantified and it is shown that the optimal schedule’s structure is based on backlog thresholds. Moreover, an off-line mechanism for determining these thresholds is provided, and further characteristics of the optimal scheduling policy under special cases is discussed. Finally, asymptotics and approximations for systems comprised of a large number of processors are considered.
Aldosterone antagonists in the treatment of heart failure.

Purpose. The clinical benefits, adverse effects, pharmacokinetics, and recommendations for the appropriate use of the aldosterone antagonists spironolactone and eplerenone in patients with heart failure are reviewed. Summary. Heart failure is a clinical syndrome characterized by the functional inability of the ventricle to meet the metabolic demands of the body. Renal hypoperfusion occurs as a result of reduced cardiac output, resulting in the activation of the renin–angiotensin–aldosterone system, which compensates for the hypoperfusion. However, this contributes to the pathology of the disease by, among other actions, increasing the release of aldosterone. Aldosterone has been shown to cause coronary inflammation, cardiac hypertrophy, myocardial fibrosis, ventricular arrhythmias, and ischemic and necrotic lesions. There are currently two aldosterone antagonists commercially available in the United States, spironolactone and eplerenone. Spironolactone is a nonselective aldosterone antagonist, and eplerenone is selective to the aldosterone receptor. Although numerous clinical trials have evaluated the efficacy of each drug, no studies have directly compared spironolactone and eplerenone. Both have been shown to improve morbidity and mortality in patients with advanced heart failure. Adverse effects of both spironolactone and eplerenone include potentially life-threatening hyperkalemia, which can be induced by renal insufficiency, diabetes mellitus, advanced heart failure, advanced age, and concurrent drug therapy. Conclusion. Spironolactone and eplerenone are life-saving agents in patients with advanced heart failure and may benefit patients with mild heart failure. Potassium and renal function must be routinely assessed to minimize the risk of life-threatening hyperkalemia.
Inspired gas-induced vascular change in tumors with magnetic-resonance-guided near-infrared imaging: human breast pilot study

This study investigates differences in the response of breast tumor tissue versus healthy fibroglandular tissue to inspired gases. Cycles of carbogen and oxygen gas are administered while measuring the changes with magnetic-resonance-guided near-infrared imaging in a pilot study of breast cancers. For two patients, analyses are performed with cross-correlation techniques, which measure the strength of hemodynamic modulation. The results show that the overall vasoresponse, indicated by total hemoglobin, of healthy tissue has approximately a 72% and 41% greater correlation to the gas stimulus than the tumor region, in two patients respectively, when background physiological changes are controlled. These data support the hypothesis that tumor vasculature has a poorly functioning vasodilatory mechanism, most likely caused by dysfunctional smooth muscle cells lining the vasculature. This study presents a methodology to quantitatively analyze inspired gas changes in human breast tumors, and demonstrates this technique in a pilot patient population.
Power transitions, institutions, and China's rise in East Asia: Theoretical expectations and evidence

Abstract Power-transition theory and institutionalist theory offer sharply contrasting views about the implications of China's rise. Power-transition theory sees China's rise as most likely dangerous because it will pose a challenge to the international order underpinned by American power. Institutionalist theory sees China's rise presenting at least an opportunity for building cooperation, rather than intensifying conflict. The logic of these two theoretical perspectives as it pertains to China's rise is explained and their different implications for three flashpoints in East Asia (the South China Sea, Korea, and the Taiwan Strait) is set forth. These expectations are then compared with the still skimpy empirical record of the post-Cold War era. Events in the South China Sea and Korea mainly lend credence to the expectations of institutionalist theory, though the evidence is arguably inconclusive. In the Taiwan Strait, however, the evidence mainly lends credence to the expectations of power-transition th...
Using Assessments to Investigate and Compare the Nature of Learning in Undergraduate Science Courses

Assessments and student expectations can drive learning: students selectively study and learn the content and skills they believe critical to passing an exam in a given subject. Evaluating the nature of assessments in undergraduate science education can, therefore, provide substantial insight into student learning. We characterized and compared the cognitive skills routinely assessed by introductory biology and calculus-based physics sequences, using the cognitive domain of Bloom's taxonomy of educational objectives. Our results indicate that both introductory sequences overwhelmingly assess lower-order cognitive skills (e.g., knowledge recall, algorithmic problem solving), but the distribution of items across cognitive skill levels differs between introductory biology and physics, which reflects and may even reinforce student perceptions typical of those courses: biology is memorization, and physics is solving problems. We also probed the relationship between level of difficulty of exam questions, as measured by student performance and cognitive skill level as measured by Bloom's taxonomy. Our analyses of both disciplines do not indicate the presence of a strong relationship. Thus, regardless of discipline, more cognitively demanding tasks do not necessarily equate to increased difficulty. We recognize the limitations associated with this approach; however, we believe this research underscores the utility of evaluating the nature of our assessments.
THE LOCATION OF THE TRANSPORT GATE IN THE NUCLEAR PORE COMPLEX

Signal-mediated nuclear transport is a gated process that occurs through a central transporter element located within the pore complex. The purpose of this investigation was to identify the region of the transporter that functions as the gate; i.e. the region that restricts passive diffusion of macromolecules through the pores. To accomplish this, small gold particles coated with polyethylene glycol (PEG; total particle diameter 40–70 A) or large PEG-particles (total diameter 110–270 A) were microinjected into the cytoplasm or nucleoplasm of Xenopus oocytes. Since PEG does not contain either nuclear import or export signals, it is assumed that the particles distribute by simple diffusion. The cells were fixed after 5 or 30 minutes and subsequently examined using TEM. The distribution of the particles located adjacent to and within the pore complexes was then mapped. The results obtained at both 5 and 30 minutes after cytoplasmic injections of small gold were basically the same. The particles readily entered the transporter but, on the average, were approximately 11 times more concentrated in the cytoplasmic half of this structure. The opposite distribution was observed following nuclear injections, i.e. the particles that were located in the transporter were approximately 7 times more numerous in the nuclear half. Our data indicate that there is a single transport gate located in the central domain of the transporter that restricts passive diffusion. The large particles that were injected into the cytoplasm migrated to the surface of the pore complex, but entered the transporter less frequently than small gold. Interestingly, the diffusion of large PEG-particles to the surface of the pores following nuclear injection was greatly restricted; however, this was not the case for similar size particles that were coated with protein containing nuclear export signals (NES). The latter results suggest that the NES is not only required for translocation, but also for migration within the nucleoplasm.
John Rawls: An Introduction

Imagine for a moment, that we—we in this liberal democracy—want to design the basic institutions of our economic and political interactions so that they are just. In order that just institutions be designed fairly, we will not be allowed to reason from our own particular circumstances. We are not to know our own race or religion, our own material resources, or even our own personal abilities and whether these abilities are valued by our society. Imagine that once this “veil of ignorance” about ourselves is lifted, we might discover that we are the person least advantaged by racist social norms or least advantaged by the relative value that our society places on skills (for example, that we have the skills of a seamstress, not of a professional basketball player). In this view of the bases for an agreement about first principles of justice, the things that we think of as “ours”—our innate skills and those we develop through education and commitment—do not entitle us to the benefits of deploying them in our political economy. Instead, our personal endowments and the value that society puts on them are morally arbitrary. From the moral view of this “original position”, choosing the principles used to guide the distribution of the benefits that accrue from exercising these should be a political decision that we make together. Yet, imagining that we might be a seamstress, a basketball player, or unemployable, each of us reasons the same way.Brooke Ackerly is Assistant Professor at Vandervilt University (brooke.ackerly@vanderbilt.edu). She is the author of Political Theory and Feminist Social Criticism (2000). Special thanks to W. James Booth, to the participants in the Vanderbilt interdisciplinary theory seminar Mark Brandon, John Goldberg, Steve Hetcher, Bob Talisse, and John Weymark and to Talisse, John Geer, and the anonymous reviewers of Perspectives on Politics.
Prolactin-Brain Interactions and Reproductive Function

SYNOPSIS. There is mounting evidence that prolactin influences reproductive function in several vertebrate species via direct action on the central nervous system. In most instances, however, the basic properties of these prolactin-induced alterations in brain function, the neurochemical mechanisms underlying these effects, and the identity of the prolactinlike molecules that might normally promote these changes have yet to be adequately characterized. Several properties of the prolactin-brain relationship that have emerged from our work in the ring dove ( Streptopelia risoria ) are described in this paper and discussed in relation to similar work in other species. Receptor binding studies using radiolabelled mammalian prolactin preparations consistently indicate the existence of saturable, high affinity binding sites for prolactin in the brains of several vertebrate species. The apparent concentration of these sites in the diencephalon is corroborated by recent mapping studies in rabbits, ring doves, and three song birds in which in vitro autoradiography and densitometry was employed. Nevertheless, direct comparisons among the three songbird species suggest some differences in the precise distribution and/or concentration of prolactin binding sites within the preoptic-hypothalamiccontinuum that may relate to species differences in the display of prolactin- related incubation behavior and parental activities. Although definitive evidence is currently lacking, it would appear that blood-borne prolactin gains access to binding sites in the central nervous system and that a receptor-mediated, blood-to-cerebrospinal fluid transport process in the choroid plexus may be a major conduit for such uptake. Recent findings from several vertebrate species also suggest that the brain may synthesize one or more prolactin-like molecules that could conceivably interact with these binding sites. Direct actions of prolactin and related hormones on brain mechanisms underlying reproductive processes are suggested by the profound dose-dependent suppression of gonadotropin secretion and gonadal activity in ring doves by intracerebroventricular administration of prolactin or growth hormone at doses that are below those required for significant peripheral actions. A major challenge for future investigation will be to identify the brain site(s) at which these and other effects of prolactin are exerted and to determine how blood-borne prolactin of pituitary origin, prolactin-like molecules of brain origin, and growth hormone-like molecules interact with each other and with other neurochemical systems to promote these types of changes under normal physiological conditions.
The presentation of health-related search results and its impact on negative emotional outcomes

Searching for health information online has become increasingly common, yet few studies have examined potential negative emotional effects of online health information search. We present results from an experiment manipulating the presentation of search results for common symptoms, which shows that the frequency and placement of serious illness mentions within results can influence perceptions of symptom severity and susceptibility of having the serious illness, respectively. The increase in severity and susceptibility can then lead to higher levels of negative emotional outcomes experienced--including feeling overwhelmed and frightened. Interestingly, health literacy can help reduce perceived symptom severity, and high online health experience actually increases the likelihood that individuals use a frequency-based heuristic. Technological implications and directions for future research are discussed.
Associations of maternal psychological factors with umbilical and uterine blood flow.

Objective. Alteration to blood flow in the maternal–foetal compartment has been proposed as a mechanism underlying maternal psychological effects on pregnancy outcomes. This study characterised the progression of umbilical and uterine blood flow resistance in healthy pregnancies and evaluated concurrent and longitudinal associations with maternal anxiety and other psychological factors.Methods. The study assessed participants (n = 107) at five visits spanning 24–38 weeks gestation. The resistance index (RI) in the uterine and umbilical arteries was measured with Doppler ultrasound. Maternal psychological function was assessed using validated, self-report instruments.Results. Hierarchical linear modelling revealed that uterine and umbilical RI decreased during the second half of gestation, and that uterine RI was lower in nulliparous women. Few concurrent associations emerged between psychological factors and RI. Longitudinal analyses determined that psychological well-being was associated with decreased l...
Student Team Performance: A Method for Classroom Assessment

By teaching teamwork, instructors can increase the likelihood of a successful project and students' abilities to work in a team. A team performance assessment instrument is tested that can be used to provide feedback throughout student team projects. The principal components analysis resulted in a 13-item, single-factor solution that explained 68.7% of the variance. Implications for educators are discussed.