cssi/SciSciGPT-SciSciNet huggingface dataset:
Prevalence of Clostridium difficile Infection among Solid Organ Transplant Recipients: A Meta-Analysis of Published Studies

Several factors including antibiotic use, immunosuppression and frequent hospitalizations make solid organ transplant (SOT) recipients vulnerable to Clostridium difficile infection (CDI). We conducted a meta-analysis of published studies from 1991-2014 to estimate the prevalence of CDI in this patient population. We searched PubMed, EMBASE and Google Scholar databases. Among the 75,940 retrieved citations, we found 30 studies coded from 35 articles that were relevant to our study. Based on these studies, we estimated the prevalence of CDI among 21,683 patients who underwent transplantation of kidney, liver, lungs, heart, pancreas, intestine or more than one organ and stratified each study based on the type of transplanted organ, place of the study conduction, and size of patient population. The overall estimated prevalence in SOT recipients was 7.4% [95%CI, (5.6-9.5%)] and it varied based on the type of organ transplant. The prevalence was 12.7% [95%CI, (6.4%-20.9%)] among patients who underwent transplantation for more than one organ. The prevalence among other SOT recipients was: lung 10.8% [95% CI, (5.5%-17.7%)], liver 9.1 % [95%CI, (5.8%-13.2%)], intestine 8% [95% CI, (2.6%-15.9%)], heart 5.2% [95%CI, (1.8%-10.2%)], kidney 4.7% [95% CI, (2.6%-7.3%)], and pancreas 3.2% [95% CI, (0.5%-7.9%)]. Among the studies that reported relevant data, the estimated prevalence of severe CDI was 5.3% [95% CI (2.3%-9.3%)] and the overall recurrence rate was 19.7% [95% CI, (13.7%-26.6%)]. In summary, CDI is a significant complication after SOT and preventive strategies are important in order to reduce the CDI related morbidity and mortality.
Telecommunications Services for Rural Educational Development.

Education in rural America is saddled with a number of special problems, which are highlighted in this report. For the most part, they relate to the social and economic characteristics of rural regions as well as their general lack of educational facilities and services. The belief that a simple solution exists for these problems is untenable, for whatever that solution may be, it is likely to require more money, facilities and specialized manpower than can be supplied. The complexities of rural development make this perfectly clear. Nonetheless, through an examination of specific areas of concern, some new, problem-solving approaches within the capabilities of rural schools and communication technology can be conceived.
Accepted Elasticity in Local Arithmetic Congruence Monoids

For certain $${a,b \in \mathbb{N}}$$ , an Arithmetic Congruence Monoid M(a, b) is a multiplicatively closed subset of $${\mathbb{N}}$$ given by $${\{x\in\mathbb{N}:x \equiv a \pmod{b}\} \cup\{1\}}$$ . An irreducible in this monoid is any element that cannot be factored into two elements, each greater than 1. Each monoid element (apart from 1) may be factored into irreducibles in at least one way. The elasticity of a monoid element (apart from 1) is the longest length of a factorization into irreducibles, divided by the shortest length of a factorization into irreducibles. The elasticity of the monoid is the supremum of the elasticities of the monoid elements. A monoid has accepted elasticity if there is some monoid element that has the same elasticity as the monoid. An Arithmetic Congruence Monoid is local if gcd(a, b) is a prime power (apart from 1). It has already been determined whether Arithmetic Congruence Monoids have accepted elasticity in the non-local case; we make make significant progress in the local case, i.e. for many values of a, b.
Osteoprotegrin Knockout Mice Demonstrate Abnormal Remodeling of the Otic Capsule and Progressive Hearing Loss

Objectives The otic capsule, when compared with other bones in the body, is unique in that it undergoes no significant remodeling of bone after development. We previously demonstrated that osteoprotegerin (OPG), which inhibits formation and function of osteoclasts, is produced at high levels in the inner ear of normal mice and secreted into the peril-ymph from where it diffuses into the surrounding otic capsule bone through a lacunocanalicular system. To test our hypothesis that the high level of OPG may be important in the inhibition of otic capsule remodeling, we studied the light microscopic histology of the otic capsule in OPG knockout mice for evidence of abnormal remodeling of bone. We also tested the hearing in OPG knockout mice to determine whether OPG and its influence on surrounding bone is important for auditory function.
Economic feasibility of agricultural management practices for reducing sedimentation in a water supply lake

Abstract The economic feasibility of using alternative agricultural management practices to reduce sedimentation and enhance water storage capacity is evaluated for a water supply lake located in northern Missouri (USA). Sedimentation of lakes is a major concern in this region because many of them serve as a municipal water supply. Net sediment delivery to the lake is estimated for 18 agricultural management practices and eight storm events using the Agricultural Nonpoint Source Pollution (AGNPS) model. Event-based sediment delivery is aggregated to an annual basis using daily rainfall and a sediment yield curve estimated with the AGNPS model. Sediment reduction benefits are estimated by the savings in groundwater pumping costs. Many of the management practices that reduce sediment delivery to the lake are not likely to be adopted by farmers because they reduce net returns to land and management relative to practices employed in 1987 and 1988. Decreases in net returns are largest when clover replaces maize in the rotation. Net returns are somewhat lower with no tillage than with minimum tillage and highest with a maize/soybean rotation, maize/soybean/wheat rotation or continuous soybeans. Sediment reduction benefits are relatively small and insufficient to offset the decreases in net returns to farmers. Five practices increase net returns and have positive social value, namely those involving the maize/wheat, maize/soybean/wheat or continuous soybean rotation and practices that maximize total net returns in the watershed.
Adaptation of stuttering frequency during repeated readings: associated changes in acoustic parameters of perceptually fluent speech.

This study is part of a series investigating the hypothesis that stuttering adaptation is a result of motor learning. Previous investigations indicate that nonspeech motor learning typically is ass...
Thermostability in endoglucanases is fold-specific

Endoglucanases are usually considered to be synergistically involved in the initial stages of cellulose breakdown-an essential step in the bioprocessing of lignocellulosic plant materials into bioethanol. Despite their economic importance, we currently lack a basic understanding of how some endoglucanases can sustain their ability to function at elevated temperatures required for bioprocessing, while others cannot. In this study, we present a detailed comparative analysis of both thermophilic and mesophilic endoglucanases in order to gain insights into origins of thermostability. We analyzed the sequences and structures for sets of endoglucanase proteins drawn from the Carbohydrate-Active enZymes (CAZy) database. Our results demonstrate that thermophilic endoglucanases and their mesophilic counterparts differ significantly in their amino acid compositions. Strikingly, these compositional differences are specific to protein folds and enzyme families, and lead to differences in intramolecular interactions in a fold-dependent fashion. Here, we provide fold-specific guidelines to control thermostability in endoglucanases that will aid in making production of biofuels from plant biomass more efficient.
Effects of Teacher Quality of Work Life in Secondary Schools on Commitment and Sense of Efficacy

ABSTRACT This paper explores the way in which teachers’ quality of work life contributes to their commitment to work and their sense of efficacy. First, a model that ties organizational characteristics of the work place to important behaviors, attitudes and psychological characteristics of teachers that effect their teaching is presented. Second, measures of quality of work life in eight schools are examined, along with the relationship between the quality of work life variables and measures of teachers’ commitment and sense of efficacy. Finally, the effects of school structure on quality of work life are examined. The data suggest that quality of work life measures are strongly associated with both dependent variables. The discussion focuses on the implications of the findings and the model for reform strategies. ∗The ideas presented in this paper were influenced by my colleagues BetsAnn Smith, Sheila Rosenblum, Stewart Purkey, and Richard Rossmiller. The research reported in this paper was supported by ...
Collective Behavior without Guile Chicago in the Late 1940s

The formal program in collective behavior at the University of Chicago was at a low point in the late 1940s, but interest in collective behavior remained prominent in race relations and several other vital programs. The early Chicago writings on collective behavior are often misinterpreted as expressions of the more recent clinical perspective and rationality debates. Robert Park viewed social unrest as a healthy rather than pathological manifestation, saw crowds as purposeful, and held that our hopes and dreams, rather than hardship and distress, are the inspiration for revolutionary activity.
Traumatic brain injury in aged animals increases lesion size and chronically alters microglial/macrophage classical and alternative activation states

Traumatic brain injury (TBI) causes chronic microglial activation that contributes to subsequent neurodegeneration, with clinical outcomes declining as a function of aging. Microglia/macrophages (MG/Mɸ) have multiple phenotypes, including a classically activated, proinflammatory (M1) state that might contribute to neurotoxicity, and an alternatively activated (M2) state that might promote repair. In this study we used gene expression, immunohistochemical, and stereological analyses to show that TBI in aged versus young mice caused larger lesions associated with an M1/M2 balance switch and increased numbers of reactive (bushy and hypertrophic) MG/Mɸ in the cortex, hippocampus, and thalamus. Chitinase3-like 3 (Ym1), an M2 phenotype marker, displayed heterogeneous expression after TBI with amoeboid-like Ym1-positive MG/Mɸ at the contusion site and ramified Ym1-positive MG/Mɸ at distant sites; this distribution was age-related. Aged-injured mice also showed increased MG/Mɸ expression of major histocompatibility complex II and NADPH oxidase, and reduced antioxidant enzyme expression which was associated with lesion size and neurodegeneration. Thus, altered relative M1/M2 activation and an nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase)-mediated shift in redox state might contribute to worse outcomes observed in older TBI animals by creating a more proinflammatory M1 MG/Mɸ activation state.
Clockwork Genres: Temperance and the Articulated Text in Late Medieval France

Abstract Generically complex texts of the fourteenth and fifteenth centuries are often characterized as "hybrids" blending lyric, prose, and narrative verse. However, closer consideration of a corpus of French "hybrids" centering on Temperance and her recently invented attribute, the mechanical clock, casts doubt on the applicability of the hybrid designation to these works. Texts such as Jean Froissart's Orloge amoureus and Christine de Pizan's Epistre Othea, as well as the novel visual iconography of Temperance that emerges in the mid fifteenth century, employ the figure of Temperance's clock to lay bare the mechanics of genre; indeed, the composite text is, like the mechanical clock, constructed as a dynamic system of interlocking parts. A fresh reading of the interplay between generic components in these texts, and between textual and visual images of Temperance, offers new perspectives on medieval genre and leads us to propose an alternative terminology and conceptual framework of not hybrid but arti...
Interfacial tension measurement between immiscible polymers: improved deformed drop retraction method

This paper describes an improvement of the technique to measure interfacial tension in immiscible polymer blends. Our method is based on the droplet retraction method, in which one relates the kinetics of relaxation of a deformed droplet to the interfacial tension between the matrix and droplet. Previously, the problem with this technique has been the difficulty in preparing axisymmetric ellipsoidal droplets. In our work, we demonstrate that perfect axisymmetric ellipsoidal droplets are produced at a later stage of relaxation of short imbedded fibers. With this technique, we utilize the strengths of both the deformed droplet method and the imbedded fiber retraction method while overcoming their shortcomings. The interfacial tension value thus obtained was compared to that by conventional methods. Additionally, the effect of confinement by external walls on the interfacial tension measurement was studied. Confinement affects interfacial tension measurement when the gap between the walls is less than two times the equilibrium drop size.
An econometric analysis of paper and wastepaper markets

Abstract The U.S. Federal government and many state governments have developed policies to encourage the recycling of wastepaper. In order to examine the effectiveness and efficiency of these policies the present paper does three things. First, we describe the U.S. market for wastepaper, with particular attention to price behavior. Second, we calculate recycling rates, and note that despite wide swings in price, recycling rates have changed little. Last we estimate an econometric model of paper and wastepaper markets to calculate price elasticities of supply and demand. We find these elasticities to be very small. This finding calls into question the effectiveness of government policy.
Optimization of Shale Gas Production Using Design of Experiment and Response Surface Methodology

High cost and uncertainty are among the most pre-eminent factors to be considered in shale gas production. Many parameters significantly affect production from such reservoirs. In this work, a new approach is proposed to obtain the optimal gas production scenario by optimizing the uncertain factors. Design of Experiment is used to analyze the order of influence of these factors, and then employ Response Surface Methodology to optimize the significant factors with economic analysis to obtain the most economical production scenario. Results show that this approach is effective and efficient for hydraulic fracturing treatment design and production scheme optimization.
Body Weight Relationships in Early Marriage: Weight Relevance, Weight Comparisons, and Weight Talk

This investigation uncovered processes underlying the dynamics of body weight and body image among individuals involved in nascent heterosexual marital relationships in Upstate New York. In-depth, semi-structured qualitative interviews conducted with 34 informants, 20 women and 14 men, just prior to marriage and again one year later were used to explore continuity and change in cognitive, affective, and behavioral factors relating to body weight and body image at the time of marriage, an important transition in the life course. Three major conceptual themes operated in the process of developing and enacting informants’ body weight relationships with their partner: weight relevance, weight comparisons, and weight talk. Weight relevance encompassed the changing significance of weight during early marriage and included attracting and capturing a mate, relaxing about weight, living healthily, and concentrating on weight. Weight comparisons between partners involved weight relativism, weight competition, weight envy, and weight role models. Weight talk employed pragmatic talk, active and passive reassurance, and complaining and critiquing criticism. Concepts emerging from this investigation may be useful in designing future studies of and approaches to managing body weight in adulthood.
Approximation of Markovian models with non-constant parameters

A generalization of the canonical correlation analysis approach has been developed for non-stationary process generated by Markovian models with non-constant parameters. This generalization, is then used to develop two model reduction (approximation) algorithms.
In vitro detection of bovine immunodeficiency-like virus using monoclonal antibodies generated to a recombinant gag fusion protein

An Escherichia coli recombinant fusion protein containing the major core protein of bovine immunodeficiency-like virus (BIV) was used to immunize mice for generation of monoclonal antibodies to BIV p26. Eight hybridomas specific for BIV p26 were identified and two antibodies, designated 104 and 142, were further characterized. Both 104 and 142 antibodies were isotyped as IgG1; they reacted specifically with both BIV p26 and the recombinant fusion protein in Western immunoblot analyses. However, the epitope specificity of the antibodies was different. Immunoperoxidase assays were used to determine if antibodies 104 and/or 142 could detect BIV replication in cell culture. Both antibodies were found to react with BIV-induced syncytia and individual BIV-infected cells. The antibodies were also used successfully in a focal immunoassay for quantitation of BIV-infected cells. These antibodies will provide valuable reagents for detection and quantitation of BIV replication in studies of viral pathogenesis and immunity.
Influence of Metal Inert Gas (MIG) Welding Factors Wire Feed Rate and Weld Travel Speed on Aluminum Weld Joint Strength

The purpose of the study was to understand effects of weld travel speed and wire feed rate in metal inert gas (MIG) welding on the aluminum materials joint strength. Initial experiments indicated a noticeable positive effect of travel speed on weld strength with an over 95% statistical significance. Nonetheless further experimentation at a significantly lower wire feed rate proved the opposite with similar statistical significance. A negative effect of welding travel speed on joint strength was measured at lower wire feed rates. In order to understand the weld travel and wire feed rate on the joint strength, a Design of Experiment (DOE) was conducted. For this experiment, weld system process factors were set constant (wave control, gas flow rate, torch angle, trim and wave type) except for travel speed and wire feed rate. A two-factor two-level full factorial design of experiment (DOE) was conducted in order to understand the effects of these two factors on weld strength. Additional welding at higher wire feed rates were conducted in order to confirmed the trend found. Results showed travel speed effects on joint strength as a result of its direct interaction with wire feed rate. This occurrence can have significant economic implications if proven to be repeatable and will be the subject of this and future MIG welding studies as they relate to aluminum structures.Copyright © 2008 by ASME
Iterative computation of marginally stable trajectories

Stability limits place restrictions on the economic operation of power systems. Calculation of these limits is therefore very important, but has traditionally been quite difficult. This paper proposes an iterative algorithm for determining parameter values that result in marginal stability of a system. (A system is marginally stable for a particular disturbance if the post-disturbance trajectory lies on the stability boundary.) The algorithm is based on Gauss–Newton solution of a nonlinear least-squares problem. Gradient information is provided by trajectory sensitivities. Copyright © 2004 John Wiley & Sons, Ltd.
Genetic basis for a mouse model of Down syndrome.

Abstract The Trisomy 16 (Ts16) mouse has been proposed as a model for Down Syndrome (DS) in humans, based on genetic homology between mouse chromosome 16 (MMU 16) and human chromosome 21 (HSA 21). Translocations of HSA 21 resulting in trisomy for only a portion of the genetic information contained on this chromosome can result in a DS phenotype. Thus, these translocations help to define a “DS region” of the chromosome. A number of genes from this DS region of HSA 21 have been mapped to MMU 16. Techniques for localizing genes on chromosomes have been used to identify the portion of MMU 16 which corresponds to the DS region of HSA 21. This region appears to be highly conserved between mouse and human, providing further support for a mouse model of DS.
Zweite Generation PEM-Brennstoffzellen. Erste Erfahrungen

In Brennstoffzellensystemen fur Automobilantriebe werden heute ausschlieslich Brennstoffzellen mit sulfonierten Membranen eingesetzt, die bei Temperaturen von 70 °C bis 90 °C betrieben werden. Die Volkswagen Aktiengesellschaft verfolgt als langfristige Perspektive die Nutzung einer mit Phosphorsaure durchsetzten Membran, die eine Betriebstemperatur bis zu 160 °C erreicht. Ziel ist es, eine signifikante Kostenreduzierung durch geringe Systemkomplexitat zu erreichen.
The 13–14 December 2001 IMPROVE-2 Event. Part III: Simulated Microphysical Budgets and Sensitivity Studies

Abstract This paper investigates the microphysical pathways and sensitivities within the Reisner-2 bulk microphysical parameterization (BMP) of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) for the Improvement of Microphysical Parameterization through Observational Verification Experiment (IMPROVE)-2 field experiment on 13–14 December 2001. A microphysical budget over the windward slope at 1.33-km horizontal grid spacing was calculated, in which the importance of each microphysical process was quantified relative to the water vapor loss (WVL) rate. Over the windward Cascades, the largest water vapor loss was associated with condensation (73% of WVL) and snow deposition (24%), and the windward surface precipitation resulted primarily from accretion of cloud water by rain (27% of WVL), graupel fallout and melt (19%), and snowmelt (6%). Two-thirds of the snow generated aloft spilled over into the lee in an area of model overpredic...
Climate variability and bank lending in the Southeast USA

Abstract In this paper, we investigate the possibility that agricultural loan portfolios of banks serving agricultural producers in the southeastern U.S. are affected by inter-annual climate fluctuations. The main finding is that La Nina years are associated with on average three times lower charge-offs and more and larger loans, in banks focusing on agricultural lending in this region. The results suggest that ENSO impact on the agricultural lending is relatively small perhaps because farmers utilize well existing insurance mechanisms and take advantage of government disaster relief payments.
The effects of diet and digestive cycle on the gastrointestinal tract pH values in the goldfish, Carassius auratus L., Mozambique tilapia, Oreochromis mossambicus (Peters), and channel catfish, Ictalurus punctatus (Rafinesque)

The digestive tract pH values of the teleost fish Oreochromis mossambicus, Carassius auratus and Ictalurus punctatus were determined in fish that were (1) starved, (2) fed herbivorous, omnivorous and carnivorous diets and (3) fed altered pH diets. The digestive tract pH profile was determined throughout an 8 h cycle. The herbivorous or carnivorous nature of the diet did not affect the pH values in any of the species. Significant differences in gut pH values were observed when the fish ingested diets with altered pHs. There was a difference between the starved and baseline fed values in Carassius auratus which was not observed in the other species. The pH values in the digestive tracts of the three species varied during the digestive cycle.
Time Estimation Performance Before, during and after Physical Activity

An experiment is reported which evaluated performance on a 10-sec time interval estimation task before, during and after physical work on cycle ergometer at intensities of 30 and 60% VO2max, as scaled to the individual subject. Results from the eleven subjects tested indicate a significant increase in variability of estimates during exercise compared to non-exercise phases. Such a trend was also seen in the mean of estimates, where subjects significantly underestimated the target interval (10 seconds) during exercise. Subjects also performed more accurately with information feedback than without knowledge of results, but they were still not able to overcome the effects of exercise. As suggested by the experimental findings, decreased estimation accuracy and increased variability can be expected during physical work and is part of a body of evidence which indicates that exercise and its severity has a substantive impact on perceptual and cognitive performance.
Surgical teaching quality makes a difference

Abstract Background: This study examined the influence of the quality of faculty members’ teaching on student performance in a third-year surgery clerkship. Methods: Eighty-nine third-year students on a surgery clerkship completed preceptor evaluation forms. The faculty member’s overall score was the mean of ratings from all the third-year students for whom that faculty member served as preceptor during the year. We examined associations between these ratings and student performance on the National Board of Medical Examiners (NBME) surgery subject examination and clerkship Objective Structured Clinical Examination (OSCE) by using an analysis of covariance that controlled for prior academic achievement [United States Medical Licensure Examination (USMLE) Part I]. Results: The average mean teaching evaluation score was associated with the scores on the NBME surgery subject examination ( P = 0.0005). Students with attendings who received poor teaching evaluations performed more poorly on OSCE data-gathering stations than did students with attendings rated as average or good. Conclusions: The study results indicate that the teaching quality of surgery faculty appears to have an impact on student performance.
Time-asymmetric initial data for black holes and black-hole collisions

As a first step in constructing initial data for dynamic black holes and general black-hole collisions, we study nonsingular vacuum Cauchy hypersurfaces with two isometric asymptotically flat ends connected by an Einstein-Rosen-type bridge. These hypersurfaces are assumed to be conformally flat and maximally embedded in space-time but are neither spherically symmetric nor time symmetric. Three of the four constraints are solved explicitly for suitable extrinsic curvature tensors that possess linear momentum and/or intrinsic angular momentum. The complete initial data are shown to transform invariantly, modulo the sign of the extrinsic curvature tensor, under inversion through a minimal two-surface that represents the ''throat'' of the geometry. These and other properties show that the data represent a particular epoch in the history of a dynamic black hole. We describe the relation of our data to that of the Schwarzschild and Kerr black holes. Finally, we discuss the generalization to encounters of two or more black holes.
High-Energy Polarized-Photon Reactions

A general formalism is presented for the analysis of production and decay distributions of meson-baryon final states resulting from interactions of polarized photons and nucleons. Particular emphasis is given to high-energy reactions and Regge-pole exchange models. Circular polarization is shown to provide a test for the presence of two or more exchanges. Linear polarization parallel or perpendicular to the production plane allows the contributions of opposite $J$-parity exchanges to be separated. This formalism enables one to make use of data at all angles, rather than limit consideration to discrete points. Applications include the separation of diffractive and pion-exchange contributions to vector-meson production, and tests for non-pole-type exchanges in baryon-resonance production. Examination of pion photoproduction reveals that no simple test exists for the discrimination between pion conspiracy and evasion models.
Increased sensitivity to rate-altering and discriminative stimulus effects of morphine following continuous exposure to naltrexone.

Two experiments evaluated whether termination of a continuous infusion of naltrexone altered sensitivity to the rate-suppressing or discriminative stimulus effects of morphine in rats. An 8-day infusion of saline or doses of 3, 10, or 18 mg/kg/day naltrexone did not alter rates of lever pressing maintained under fixed-ratio 30 schedules of food delivery. A dose of 10 mg/kg/day naltrexone produced insurmountable antagonism of the rate-suppressing and analgesic effects of morphine. The ED50 of morphine for rate suppression decreased by 2-fold 1 day after termination of the 8-day infusion of 10 or 18 mg/kg/day naltrexone. The ED50 of morphine returned to initial values within 8 days. Termination of infusion of either saline or 3 mg/kg/day naltrexone did not alter the ED50 of morphine. Changes in morphine stimulus control were evaluated in rats trained to discriminate saline and 3.2 mg/kg morphine under fixed-ratio 15 schedules of food delivery. The ED50 of morphine for stimulus control or rate suppression decreased by 2-fold 1 day after termination of an 8-day infusion of 18 mg/kg/day naltrexone. The ED50 of morphine for rate suppression returned to initial values within 3 days; that for stimulus control, within 5 days. Thus, termination of exposure to high doses of naltrexone produced brief changes in sensitivity to the rate-altering and discriminative stimulus effects of morphine that parallel reported changes in sensitivity to the analgesic and lethal effects of morphine.
Congenital Abdominal Aortic Aneurysm and Hypertrophic Pyloric Stenosis in an Infant

Infantile abdominal aortic aneurysms are rare, usually detected incidentally, and associated with connective tissue disease or due to iatrogenic causes. The diagnosis should be considered when a large cystic mass (especially pulsatile) is found in a neonate and confirmed using color and duplex sonography. Undiagnosed aneurysms have a high mortality rate. Surgical treatment is warranted when the patient is stabilized and may result in a normal outcome, although future graft replacement may be necessary.
Towards a theory of sustainable systems

Abstract While there is tremendous interest in sustainability, a fundamental theory of sustainability does not exist. We present our efforts at constructing a theory from Information Theory and Ecological Models. We discuss the state of complex systems that incorporate ecological and other components in terms of dynamic behavior in a phase space defined by the system state variables. From sampling the system trajectory, a distribution function for the probability of observing the system in a given state is constructed, and an expression for the Fisher information is derived. Fisher information is the maximum amount of information available from a set of observations, in this case, states of the system. Fisher information is a function of the variability of the observations such that low variability leads to high Fisher information and high variability leads to low Fisher information. Systems in stable dynamic states have constant Fisher information. Systems losing organization migrate toward higher variability and lose Fisher information. Self-organizing systems decrease their variability and acquire Fisher information. These considerations lead us to propose a sustainability hypothesis: “sustainable systems do not lose or gain Fisher information over time.” We illustrate these concepts using simulated ecological systems in stable and unstable states, and we discuss the underlying dynamics.
Coding for low-power address and data busses: a source-coding framework and applications

Presented in this paper is a source-coding framework for the design of coding schemes to reduce transition activity. These schemes are suited for high capacitance busses where the extra power dissipation due to the encoder and the decoder circuitry is offset by the power savings at the bus. A framework to characterize low-power encoding schemes is developed based upon the source-channel coding view. In this framework, a data source (characterized in a probabilistic manner) is passed through a decorrelating function f/sub 1/ first. Next, a variant of entropy coding function f/sub 2/ is employed, which reduces the transition activity. The framework is then employed to derive novel encoding schemes whereby practical forms for f/sub 1/ and f/sub 2/ are proposed. Simulation results with an encoding scheme for data busses indicate an average reduction in transition activity of 36%. This translates into a reduction in total power dissipation for bus capacitances greater than 14 pF/bit in 1.2 /spl mu/ CMOS technology and eight times more pourer savings compared to existing schemes with a typical value for bus capacitance of 50p F/bit. Simulation results with an encoding scheme for instruction address busses indicate an average reduction in transition activity by a factor of 3 times and 1.5 times over the Gray and TO coding schemes respectively.
Do nonlinear measures of heart rate variability track muscle sympathetic nerve activity during central hypovolemia in humans

Objective: Although linear measures of heart rate variability (HRV) (eg, RR interval high frequency, RR interval low frequency) have been associated with autonomic function, it is unclear whether nonlinear measures (ie, entropy and fractality) are similarly associated. We therefore hypothesized that nonlinear metrics of HRV would be correlated with the progressive increase in muscle sympathetic nerve activity (MSNA) induced by central hypovolemia. Methods: Twelve (7 male/5 female) healthy subjects (age, 32 ± 3 years; height, 172 ± 3 cm; weight, 80 ± 5 kg) underwent progressive lower body negative pressure (LBNP) to presyncope. Electrocardiogram and muscle sympathetic nerve activity from the peroneal nerve were measured continuously. Linear (RR interval high frequency, RR interval standard deviation, pNN50) and nonlinear (sample entropy, fractal dimensions by curve length and dispersion analysis, symbol dynamics) indices of HRV were calculated at each level of LBNP and recovery. Muscle sympathetic nerve activity was calculated as bursts per 100 heart beats (b/100 hb). Results: Muscle sympathetic nerve activity increased from 22.8 ± 2.9 b/100 hb at baseline to 46.6 ± 6.2 b/100 hb at –80 mmHg LBNP (P b .001) and returned to 21.6 ± 5.3 b/100 hb during recovery. All HRV indices decreased with LBNP and increased with recovery, resulting in inverse correlations withMSNA. The linear HRV indices were strongly correlated with MSNA (amalgamated R ≥ 0.79), whereas the only nonlinear index with an amalgamated R of 0.79 or higher was fractal dimension by dispersion analysis (R = 0.79). Conclusion: Although nonlinear indices of HRV decrease with reduced central blood volume, they are not as tightly associated with sympathetic responses as linear indices of HRV.
On a slow drift of a massive piston in an ideal gas that remains at mechanical equilibrium

We consider a heavy piston in an inflnite cylinder surrounded by ideal gases on both sides. The piston moves under elastic collisions with gas atoms. We assume here that the gases always exert equal pressures on the piston, hence the piston remains at the so called mechanical equilibrium. However, the temperatures and densities of the gases may difier across the piston. In that case some earlier studies by Gruber, Piasecki and others reveal a very slow motion (drift) of the piston in the direction of the hotter gas. At the same time the energy is slowly transferred across the piston from the hotter gas to the cooler one. While the previous studies of this interesting phenomenon were only heuristic or experimental, we provide flrst rigorous proofs assuming that the velocity distribution of the ideal gas satisfles a certain \cutofi" condition.
Evolution of Composite Right/Left-Handed Leaky-Wave Antennas

In this paper, the evolution of the composite right/left-handed (CRLH) leaky-wave antennas (LWAs) yielding several novel CRLH LWA is reviewed. Starting with the concept of CRLH LWAs, the concave and convex passive CRLH LWAs are discussed along with the conformation effects in each case and a dispersion engineering method is introduced to compensate for the conformation effect to refocus the main radiation beam. Next, planar and conformal varactor-based electronically controlled CRLH LWAs are reviewed. In the planar case electronic beam steering and beamwidth controlling are discussed while in the case of conformal version electronic radiation aperture selectivity as well as electronic beam focusing is discussed. Finally, a dual polarized CRLH LWA is presented which is a balanced four-port coupled CRLH LW-TL that conserves its CRLH nature under both common-mode and differential-mode excitations but with two orthogonal E-planes resulting in two orthogonal polarizations for the radiated fields.
Novel self-stressing test structures for realistic high-frequency reliability characterization

A series of self-stressing test structures suitable for investigation of reliability failure mechanisms (hot carriers, electromigration, oxide breakdown) under realistic integrated circuit operating conditions, is described. These structures contain DC-controlled, high-frequency on-chip oscillators, which stress test structures. As a result, high-frequency (>200-MHz) stress-testing can be performed using less expensive DC test systems. In particular, hot-carrier stress-testing was performed at frequencies up to 230 MHz, which is the highest stress frequency reported for inverters. For the 1- mu m technology examined, the quasi-static model accurately describes the degradation. The statistical variation in high-frequency, hot-carrier-induced degradation is presented, and variations with temperature are shown to be consistent with DC stress results. Since only DC test systems are needed, these structures provide a simple method to calibrate reliability simulators and characterize high-frequency reliability effects. >
Diseases and pathology of chimpanzees at the southwest foundation for biomedical research

The Southwest Foundation for Biomedical Research (SFBR) chimpanzee colony is a conventionally housed production and research population. The present population is 203 chimpanzees, consisting of 87 males and 116 females. Fifty-four apes were born between 1985 and 1989, 56 from 1980 to 1985, 49 from 1975 to 1980, 24 from 1965 to 1975, and 20 from 1954 to 1965. Twenty-five apes were added to the colony from outside sources over the last 10 years. The average yearly mortality for the past 8 years was 2.4%. The primary causes of death since 1982 were heart disease (6), trauma (5), and respiratory disease (4). The heart lesions included myocarditis, necrosis, fibrosis, and mineralization. The respiratory disease deaths were due to Streptococcus pneumoniae and Klebsiella pneumoniae. The traumatic deaths were primarily in young chimpanzees and were caused by adults. Since 1976, 20 stillbirths occurred and were not included in the total deaths. There were two cases of placenta previa and one of abruptio placentae. Clinical conditions not leading to death included respiratory disease, parasitism, alopecia, diarrhea, maternal rejection, and trauma. The most significant commonly isolated bacteria were Staphylococcus, Streptococcus, Haemophilus, Klebsiella, Citrobacter, and Campylobacter. The most common intestinal parasites were Balantidium, Entamoeba, Chilomastix, Iodamoeba, Giardia, Trichuris, Enterobius, and Strongyloides. The colony pathology is sketchy from 1967 to 1981, but the main causes of death during this period were probably pneumonia and intestinal disease.
A resource-based view of e-tailer performance: an international study

Worldwide, e-tailing has grown considerably over the past few years, with growth rates exceeding those of traditional retailing. This study builds on the resource-based view (RBV) of the firm (Barney, 1991) in identifying resources less susceptible to imitation by examining the effects of resources (brand strength, market orientation, distribution effectiveness, foreign market know-how and willingness to cannibalise) on e-tailer performance. A cross-national survey of e-tailers was conducted to assess these relationships. The results of the regression analyses show that the resources in this study, with the exception of distribution effectiveness, are predictors of e-tailer performance although their relative strength varies across samples. These results have implications for both academics and practitioners. For academics, the findings suggest that resources that are relatively inimitable drive e-tail performance. Identifying other such resources provides direction for future research. For managers, this study demonstrates the importance of investing in resources that are not observable to the competition, thus enabling an e-tailer to build and sustain a competitive advantage.
[2]Rotaxane with a cation-binding wheel

A [2]rotaxane with a crown ether-containing wheel component is synthesized and shown to bind K+ which alters the rotaxane’s dynamic properties.
The Pharmacodynamics of β-Lactams

Considerable information on the pharmacodynamics of beta-lactams has accumulated in the past 20 years. In vitro, beta-lactams demonstrate time-dependent killing and variable postantibiotic effects. Animal models have shown that the time for which drug levels exceed the minimum inhibitory concentration (MIC) correlates best with bacterial eradication, and this is now being borne out in human studies. In investigations on osteomyelitis and endocarditis, trough serum inhibitory titers have generally correlated better with cure than have peak titers, and studies that have analyzed outcomes in relation to the MIC for the infecting pathogen have shown decreasing clinical efficacy with increasing MICs. One prospective study has shown that time above MIC correlated better with time to pathogen eradication than did area under the curve. In some continuous-infusion studies, significantly better outcomes were achieved with continuous infusion against susceptible bacteria or for patients with persistent, profound neutropenia. With use of time above MIC as the predictor of efficacy, it is possible to reexamine current dosing schedules critically.
Field growth comparisons of invasive alien annual and native perennial grasses in monocultures

Abstract Throughout the western United States, the invasive annual grass, medusahead (Taeniatherum caput-medusae L. Nevski), is rapidly invading grasslands once dominated by native perennial grasses, such as bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) A). It is also invading grasslands dominated by less undesirable invasive annual grasses, especially cheatgrass (Bromus tectorum L.). Understanding medusahead growth dynamics relative to native perennial grasses and cheatgrass is central to predicting and managing medusahead invasion. We hypothesized that medusahead would have a higher relative growth rate (RGR), a longer period of growth, and as a consequence, more total biomass at the end of the growing season than the native perennial grass and cheatgrass. In 2008 (dry conditions), 250 seeds and in 2009 (wet conditions), 250 and 100 seeds of each species were sown in 1 m2 plots with 5 replicates. Shoots were harvested on 3–25 day intervals throughout the growing season. The native perennial grass had more biomass and higher RGR than medusahead in the dry year, but the relationship was reversed in the wet year. Precipitation in 2008 was well-below average and this level of drought is very infrequent based on historical weather data. Medusahead had a longer period of growth and more total biomass than cheatgrass for both years. We expect that medusahead will continue to invade both native perennial and less undesirable invasive annual grasslands because of its higher RGR and extended period of growth.
Computational efficiency of the Gabor transform

The two-dimensional Gabor transform has been proposed as a model of the visual receptive field of the simple cells of the mammalian striate cortex. The authors analyze the computational steps needed to achieve this transformation and present typical execution times for several computers. The use of an adaptive iteration step size is shown to improve performance significantly. Computational requirements are examined for both sequential and parallel computers. A parallel computer with global addition capability and with a processor for each pixel could perform a Gabor transform in real time. On existing computers, real-time performance is not possible for moderate sized images. Sequential computers show better cost/performance ratios than parallel machines. >
Dural ectasia and the Marfan syndrome

The not-uncommon spinal abnormalities associated with Marfan's syndrome rarely undergird clinical problems, and neurological features accompanying such bone abnormalities are rare. In such unusual circumstances it is a widened vertebral canal that attracts attention: the substrate of such widening is dural ectasia with bone erosion, presumably due to hydraulic forces operating via the cerebrospinal fluid (CSF). When neural symptoms or findings do occur they may be related to stretching and traction mechanisms. This study of a symptomatic patient defined with reasonable clarity the abnormal anatomy, and some neurological symptom relief was achieved by attempting to alter the CSF dynamics. The relevant literature has been sampled to elucidate the condition.
Electrostatic Binding of Metal Complexes to Electrode Surfaces Coated with Highly Charged Polymeric Films

Previous reports in which metal complexes have been attached to electrode surfaces coated with polymeric molecules have depended upon the formation of covalent or coordination bonds in the attachment procedure (1-4). Such schemes can be quite successful but depending, as they do, on rather specific surface chemistry, they are not applicable to as wide a variety of metal complexes as might be desirable. We have observed that coating graphite electrodes with polymers bearing charged ionic groups produces surfaces which strongly bind multiply-charged metal complexes bearing charges opposite to that on the attached ionic polymer. By exploiting this observation it is entirely possible that virtually any desired metal ion can be attached in large quantities to electrode surfaces by coordinating the metal ion with ligands that produce a multiply-charged complex ion.
Understanding structural problems in structural damping with bond graphs

There are some structures, particularly in outer space applications but also on earth, which are inherently lightly damped and hence vibrate a long time after excitation. In many cases, much of the damping that does exist comes from dry friction in bolted joints. It has been shown that controlling the clamping force at a joint, thus creating a semi-active damping element, can increase this type of damping.In this study, simple examples of bending mode subsystems coupled by a controlled joint are analyzed. Using bond graphs, which are particularly useful in the description of vibratory systems, it is shown that certain structural features of the system may limit the added damping achievable by the semi-active joint to very low values for certain system modes.
Improving multirobot, cooperative search via local target queues

Multirobot coordination techniques range from sharing state and intent information to explicit coordination strategies. The choice of cooperation strategy can affect task performance and resource utilization. This paper investigates the use of local search queues, rather than globally shared search queues. This work shows this change improves search in terms of interference and communications loads, two key factors in multirobot search, without significantly impacting time-to-search and coverage metrics.