cssi/SciSciGPT-SciSciNet huggingface dataset:
Characterizing the nonlinear viscoelastic properties of sealant, including its Mullins effect

Quantification of mechanical properties, such as nonlinear viscoelastic behavior, for a cured sealant is complicated by the presence of the Mullins effect. This article examines the mechanical behavior of five different sealants materials encompassing the range of currently available commercial sealant formulations. The Mullins effect was observed for all materials and was present in both tensile and compression experiments. If a previously tested sample was allowed to rest (remain unloaded) for a sufficiently long period of time, however, the Mullins effect was partially recovered; that is, the modulus measured during the first mechanical loading following the rest period was greater than that obtained on subsequent loadings. Samples were then preloaded to remove the Mullins effect, and their nonlinear viscoelastic properties were examined using stress–relaxation experiments. Although the behavior was complex, the time and strain dependences were sufficiently independent so that time–strain superposition could be used to simplify modeling and characterization without introducing significant errors. A simple empirical equation was formulated to describe the behavior for all five sealants over the range of strains and time scales examined. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
An experimental study of plane bubbles rising at inclination

Abstract The characteristics of bubbles rising in two-dimensional tanks is investigated. It is found that the influence of fluid properties, while negligible for vertically rising bubbles, measurably affects the inclined bubble rise velocity. The measured increase in the rise velocity at inclination relative to the vertical value is explained qualitatively. In addition, a comparison is made between the wave analogy correlation of Maneri & Mendelson and vertical rise velocity data. The comparisons show that the correlation predicts the three-dimensional effects of tank spacing when the data are reduced on an equivalent bubble radius basis.
The acid-base effects of free water removal from and addition to oxygenated and deoxygenated whole blood: An in vitro model of contraction alkalosis and dilutional acidosis

This study was conducted to describe the acid–base effects of hydration and dehydration of oxygenated and deoxygenated whole blood. Whole blood samples from goats were equilibrated in a tonometer to a partial pressure of carbon dioxide of 40 mm Hg and oxygen (PO 2 ) of 100 mm Hg or 30 mm Hg. Contraction alkalosis was achieved by evaporating blood samples to 80% of the original volume. Dilutional acidosis was achieved by increasing the blood sample volume by 20% by addition of sterile water. Acid–base, electrolyte, hemoglobin, lactate, albumin, and phosphorus concentrations were measured at baseline and after dehydration or hydration. A 20% dehydration of whole blood caused a 22% increase in sodium concentration and a significant increase in base excess of +3 mEq/L ( P P
Implementation of Mindfulness Training for Mental Health Staff: Organizational Context and Stakeholder Perspectives

Occupational stress and burnout adversely impacts mental health care staff well-being and patient outcomes. Mindfulness training reduces staff stress and may improve patient care. However, few studies explore mental health setting implementation. This qualitative study used focus groups to evaluate stakeholders' perceptions of organizational factors affecting implementation of an adapted version of Mindfulness-Based Stress Reduction (MBSR) for staff on adolescent mental health units. Common facilitators included leadership securing buy-in with staff, allocating staff time to participate, and quiet space for training and practice. Other facilitators were past staff knowledge of mindfulness, local champions, and acculturating staff with mindfulness through a non-mandatory training attendance policy. Common barriers were limited staff time to attend training sessions and insufficient training coverage for some staff. Staff also reported improved focus when interacting with adolescents and improved social cohesion on the units. We conclude that a mindfulness-based program for reducing occupational stress can be successfully implemented on adolescent mental health units. Implementation appeared to change the social context of the units, including staff and patient interactions. More broadly, our findings highlight the importance of environmental factors in shaping attitudes, diffusion of innovation, and acculturation of wellness program implementations.
The reactions of diethylzinc on gallium-rich and arsenic-rich reconstructions of GaAs(100)

Abstract Temperature programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS) were used to investigate the reaction of diethylzinc (DEZ) on the Ga-rich (4×2) and As-rich (2×4) and c(4×4) reconstructions of GaAs(100). DEZ dissociatively adsorbed on all three surfaces to form ethyl groups and Zn atoms. The strength of Zn–surface interaction was found to be a function of surface As/Ga ratio. Adsorbed Zn atoms desorbed at 560 K on the Ga-rich (4×2) reconstruction and 585 K on the As-rich (2×4) reconstruction. For the c(4×4) surface, the primary Zn desorption feature was also at 585 K; however, additional Zn desorption features appeared between 600 and 700 K. In contrast to the interaction of Zn with GaAs(100), only minor variations in the reaction pathways for surface ethyl groups were observed as the surface As/Ga ratio was varied. The primary reaction pathway for ethyl groups on all three surfaces was β-hydride elimination at 570 K to produce ethylene. The ethylene yield was found to increase with increasing surface Ga concentration.
Information Technology in Transition Economies

The break-up of the Soviet Union resulted in many formerly centrally planned and highly controlled economies to experience radical reforms that fully changed the business landscape. With the political and economic changes happening, many businesses and organizations in transition economies not only experienced major restructuring, but also acquired increased access to modern information technology (IT). Though much of the development in transition economies is supported by IT, there is not much published research dealing with the role of IT specifically in transition economies. The objective of this special issue is to stimulate research in this important area. In this introduction to the special issue, distinctive business and social conditions in transition economies, and the potential impacts of such conditions on IT use, as well as factors which may inhibit research of IT in transition economies are discussed.
Impact of Objectively Assessing Surgeons' Teaching on Effective Perioperative Instructional Behaviors

Importance Advancing surgical technology and decreasing resident learning hours have limited exposure to perioperative training, necessitating more effective and efficient perioperative teaching by faculty surgeons. Participation in collaborative efforts and process improvement can change behaviors and enhance teaching. Objectives To promote deliberate teaching of residents, change resident perception of their teachers, and produce sustainable improvements by objectively measuring surgeons’ perioperative teaching performance. Design, Setting, and Participants This 3-phase observational study of surgeons’ perioperative teaching behaviors included university-based surgeons, general surgery residents, and preclinical student observers and involved elective cases at a 600+ bed tertiary hospital. Initially, we measured teaching behaviors by surgeons unaware of study objectives, provided aggregate and confidential individual feedback, and developed standardized preoperative briefings and postoperative debriefings. Phase 2 applied a deliberate teaching model and reinforced behaviors with continuous process improvement efforts (Plan, Do, Check, Act) and repeat observations. Phase 3 used resident prompts to enhance teaching behaviors and demonstrate sustainability. Resident surveys conducted 3 times assessed perceptions of deliberate guidance by faculty when compared with national benchmarks. Interventions Introduction of deliberate faculty preprocedural focusing and postprocedural reinforcement to facilitate resident learning. Main Outcomes and Measures More frequent and complete perioperative teaching by faculty and the perception of enhanced teaching by residents. Results Faculty more commonly and more completely performed the 10-step preoperative briefings and postoperative debriefings ( P P = .02) and requests for resident self-evaluation ( P = .006). Conclusions and Relevance Objective recording of teaching behavior frequency motivated adoption of deliberate guided teaching behaviors by surgeons, resulting in both subjective reports by residents of more frequent teaching and objective recording of parallel improvements. A deliberate focus on objectively assessing surgeon educators’ periprocedural teaching may motivate improved teaching.
Preventing the bullying of foster children in our schools

Abstract This study examines the difficulties that the foster care child has with bullying in school, and it asks the question, “What is currently known about the bullying of foster children?” Furthermore, this article examines what the research believes can be done to solve these problems and improve the chances that a foster child will not be bullied in school. It asks and answers the questions, “What can schools do to help eliminate the bullying of foster children?” and “What can be concluded about how schools can help foster children improve their overall success in school?”
Does Self-Reported Posttraumatic Growth Reflect Genuine Positive Change?

In this study, we evaluated the validity of self-reported posttraumatic growth (PTG) by assessing the relation between perceived growth and actual growth from pre- to posttrauma. Undergraduate students completed measures tapping typical PTG domains at Time 1 and Time 2 (2 months later). We compared change in those measures with scores on the Posttraumatic Growth Inventory (PTGI; Tedeschi & Calhoun, 1996) for those participants who reported a traumatic event between Time 1 and Time 2 (n = 122). PTGI scores generally were unrelated to actual growth in PTG-related domains. Moreover, perceived growth was associated with increased distress from pre- to posttrauma, whereas actual growth was related to decreased distress, a pattern suggesting that perceived and actual growth reflect different processes. Finally, perceived (but not actual) growth was related to positive reinterpretation coping. Thus, the PTGI, and perhaps other retrospective measures, does not appear to measure actual pre- to posttrauma change.
Laparoscopic radical prostatectomy: review and assessment of an emerging technique

Several recent reports have affirmed the feasibility of the laparoscopic approach for radical prostatectomy. In this review, we discuss the morbidities associated with this technique and compare outcomes and convalescence with standard open radical prostatectomy. We reviewed all currently published data on laparoscopic radical prostatectomy and our series of 45 robotic-assisted radical prostatectomies and compared them to several landmark series of open retropubic and perineal radical prostatectomies. Although the initial series reported long operating times, these times have been significantly reduced in more recent series. Data on blood loss, convalescence, impotence, and incontinence rates have also been promising. Although follow-up has been short thus far, laparoscopic radical prostatectomy has been shown to be similar to open radical prostatectomy in several areas.
Spectroscopic changes accompanying some reactions of trypsin and α-chymotrypsin

Difference spectrophotometry is used to measure changes in the ultraviolet spectra of trypsin and α-chymotrypsin caused by complexation with some of their substrates. The sign of the trypsin/ligancl difference spectra is opposite to the sign of the α-chymotrypsin/ligand spectra. The detailed appearance of the spectra depends upon the enzyme/ligand combination. The trypsin vs trypsinogen difference spectrum has the same sign and shares some of the peak locations found in the trypsin/substrate spectra; the chymotrypsin vs chymotrypsinogen difference spectrum shares several peak locations with the α-chymotrypsin/substrate spectra. The concentration dependence of the α-chymotrypsin/p-toltienesulfonyl- L -arginine methyl ester difference spectrum fits the assumption that the species responsible for the difference spectrum is in equilibrium with free enzyme and substrate; the dissociation constant obtained is the same as the Michaelis-Menten constant obtained by kinetic analysis.
Red beech death in the Maruia Valley South Island, New Zealand

Abstract Many red beech trees died in parts of the Maruia Valley between 1978 and 1980 following an outbreak of the scale insect Inglisia fagi. Annual diameter increment of trees and climatic data suggest the primary cause to be a series of spring droughts between 1974 and 1978. In the worst affected stands of mixed red and silver beech a large proportion of the red beech trees died. Release from competition was reflected in the greatly increased growth rate of the residual silver beech which generally was not heavily attacked by the scale insect; early response of surviving red beech was limited because of reduced foliage.
Quantisation of Antibody Hæmagglutinin Activity using Electronic Cell Counting

AGGLUTINATION is the most characteristic and widely used reaction for detecting antigen–antibody reactions of red blood cells. The reaction itself is highly sensitive and specific. The quantitation of agglutinin activity generally has been limited to the use of two-fold serial dilution methods, and since such methods are adequate for most routine clinical determinations there has been little interest in the development of quantitative methods. Where more detailed information is desired, the serial dilution methods are inadequate and a procedure of sensitivity and precision would facilitate the examination of a variety of problems related to human blood groups which at present cannot be attempted.
Pairs of sequences with a unique realization by bipartite graphs

Pairs of sequences which have a unique realization by bipartite graphs (up to isomorphism) are characterized.
Effects of antegrade and retrograde machine perfusion preservation on cardiac function after transplantation in canines.

Abstract Introduction Most studies investigating machine perfusion preservation for heart transplantation perfuse through the aortic root (antegrade), but the coronary sinus (retrograde) is a potential option. We hypothesized that retrograde machine perfusion provides better functional protection than static storage, while avoiding the potential irregular perfusion seen when aortic insufficiency occurs with antegrade perfusion. Materials and Methods Eighteen canine donor hearts were arrested, procured, and stored in modified Celsior solution for 4 hours by using either static storage at 0°C to 4°C (n = 6) or machine perfusion preservation at 5°C via the aortic root (antegrade, n = 6) or coronary sinus (retrograde, n = 6). Lactate and myocardial oxygen consumption were measured in perfused hearts. Hearts were reimplanted and reperfused for 6 hours with hourly function calculated by using the preload recruitable stroke work (PRSW) relation. Myocardial water content was determined at the end of the experiment. Results Storage lactate levels and myocardial oxygen consumption were comparable in both perfused groups. The PRSW was increased immediately after bypass in the antegrade group (120.6 ± 19.1 mm Hg) compared with the retrograde (75.0 ± 11.3 mm Hg) and static (78.1 ± 10.5 mm Hg) storage groups ( P P Conclusions Both antegrade and retrograde perfusion demonstrated excellent functional preservation, at least equivalent to static storage. Initial function was superior in the antegrade group, but the retrograde hearts displayed better function late after reperfusion. Neither perfused group developed significant edema. Machine perfusion preservation is a promising technique for improving results of cardiac transplantation.
Genome-Wide Association Study of Copy Number Variations (CNVs) with Opioid Dependence

Single-nucleotide polymorphisms that have been associated with opioid dependence (OD) altogether account for only a small proportion of the known heritability. Most of the genetic risk factors are unknown. Some of the ‘missing heritability’ might be explained by copy number variations (CNVs) in the human genome. We used Illumina HumanOmni1 arrays to genotype 5152 African-American and European-American OD cases and screened controls and implemented combined CNV calling methods. After quality control measures were applied, a genome-wide association study (GWAS) of CNVs with OD was performed. For common CNVs, two deletions and one duplication were significantly associated with OD genome-wide (eg, P ¼2 � 10 � 8 and OR (95% CI) ¼0.64 (0.54– 0.74) for a chromosome 18q12.3 deletion). Several rare or unique CNVs showed suggestive or marginal significance with large effect sizes. This study is the first GWAS of OD using CNVs. Some identified CNVs harbor genes newly identified here to be of biological importance in addiction, whereas others affect genes previously known to contribute to substance dependence risk. Our findings augment our specific knowledge of the importance of genomic variation in addictive disorders, and provide an addiction CNV pool for further research. These findings require replication. Neuropsychopharmacology (2015) 40, 1016–1026; doi:10.1038/npp.2014.290; published online 19 November 2014
Sickle Cell Disease Pain in Children and Adolescents: Change in Pain Frequency and Coping Strategies Over Time

Examined 9-month follow-up data obtained from children and adolescents with sickle cell disease (SCD) and their parents participating in a longitudinal study of pain coping strategies. Of 87 subjects completing the baseline assessment of pain coping strategies, 70 (80%) of their parents completed a structured pain interview assessing their child's health care use and activity reduction during painful episodes over the follow-up period. Regression analyses controlling for age and pain frequency revealed that baseline Coping Attempts were associated with higher levels of school, household, and social activity during painful episodes. Baseline Passive Adherence was associated with more frequent health care contacts during the subsequent 9 months. Increases in Negative Thinking over time were associated with further increases in health care contacts during the follow-up period. Comparing pain coping strategies assessed at baseline to pain coping strategies measured at follow-up revealed that pain coping strategies were relatively stable over time for younger children but changed more for adolescents.
Testing of quantum cellular automata

There has been considerable research on quantum dot cellular automata (QCA) as a new computing scheme in the nanoscale regimes. The basic logic element of this technology is the majority voter. In this paper, a detailed simulation-based characterization of QCA defects and study of their effects at logic level are presented. Testing of these QCA devices at logic level is investigated and compared with conventional CMOS-based designs. Unique testing features of designs based on this technology are presented and interesting properties have been identified. A testing technique is presented; it requires only a constant number of test vectors to achieve 100% fault coverage with respect to the fault list of the original design. A design-for-test scheme is also presented, which results in the generation of a reduced test set at 100% fault coverage.
The impact of psychological factors on placebo responses in a randomized controlled trial comparing sham device to dummy pill.

Objectives To explore to what extent psychological factors such as expectation, depression, anxiety, and belief in alternative medicine impact placebo response and differential responses to separate placebo interventions.
Oil-Price Shocks: Beyond Standard Aggregate Demand/Aggregate Supply Analysis.

The author explores the problems of portraying oil-price shocks using the aggregate demand/aggregate supply model. Although oil-price shocks are the most commonly cited examples of aggregate supply shocks, they violate the model's assumption of constant relative prices (as acknowledged by the label, "oil-price shocks"). The resulting problems are effectively masked in textbook presentations by implicitly assuming that the supply shocks occur in a closed economy. However, the typical discussion is glaringly inaccurate when dis- cussing the effects of oil-price shocks on oil-rich countries. Thus, the cogency of the standard model's representation of oil-price shocks on open economies is compromised. A simple modification of the model that differentiates between production and absorption goods enables it to better reflect the effects of oil-price shocks on open economies.
Output, inflation, and interest rates in an estimated optimizing model of monetary policy

Abstract This paper examines the impact of sticky price and limited participation frictions, both separately and combined, in a dynamic stochastic general equilibrium model. Using U.S. data on output, inflation, interest rates, money growth, consumption, and investment, likelihood ratio tests and Bayesian pseudo-odds measures reveal that the data prefers a model with both structural features. Our results also show that the combined model mimics many important features of the business cycle. In particular, the model generates plausible impulse responses, and monetary policy shocks are responsible for only a modest amount of output, inflation, and nominal interest rate movements.
Gradient and Discrete Region Composites Produced by Solid Free Form Fabrication Techniques

Stereolithography patterns have been used to create composites with gradient properties. Patterns are produced with an open cellular or columnar structure inside a surface shell. This serves as a host for filler materials, generally epoxies or polyurethane matrices loaded with various fibers or microspheres. Regions within a single object may be separated by thin barriers, allowing filling with different matrix materials to create regions of differing local properties. The internal structure can also be continually gradated in dimension to produce composites with properties ranging from that of the filler material to that of the SFF material, currently epoxy or ABS plastic. This is a general set of processes that can be applied to a variety of existing Solid Freeform Fabrication systems.
A Fast Four-Point Sense Methodology for Extraction of Circuit-Relevant Degradation Parameters

A fast measurement methodology to extract, in a single stress sequence, four different circuit-relevant degradation parameters is introduced. The methodology is used to compare the degradation of the linear and saturation drain currents, as well as the linear and saturation threshold voltages, during positive bias temperature instability (BTI) (PBTI) in metal-gate/high-k (MG/HK) nFETs and during negative BTI (NBTI) in conventional poly-Si/SiON pFET devices. No gm degradation is observed for PBTI in MG/HK nFET devices, whereas gm degradation is evident for NBTI in conventional poly-Si/SiON pFETs. Furthermore, the impact of measurement delay on parameter correlation is investigated, leading to important conclusions regarding the physical origin of gm degradation during BTI stress.
Network centric warfare: Organizational collaboration as a key enabler

Distributed work, globalization and changing situational demands have required that military warfare tactics shift from slower conventional operations to agile, dynamic strategies. Therefore, a better understanding of more dynamic, modern-day context is needed. The present research explored the concept of collaboration in the context of network centric warfare (NCW) and evaluated a metric to assess collaboration at the organizational level. Personnel (n = 240) from a logistics command and control organization completed a series of survey items as part of an ongoing organizational assessment. Results from a factor analysis indicated that organizational collaboration could be conceptualized according to four factors: collaboration effectiveness, collaboration adaptability, collaboration enablers, and job characteristics. The four factors were also examined to determine their relationship to other constructs, such as cohesion and trust, which are integral factors present in collaborative, dynamic environments. All four factors were positively related to organizational trust and group cohesion, thus providing concurrent validity to the organizational collaboration construct. The four factors depicted the complexity of socio-technical systems and could be used as a framework for future research on collaboration and development of collaborative systems. Implications for NCW are discussed.
Skin stem cells: rising to the surface

The skin epidermis and its appendages provide a protective barrier that is impermeable to harmful microbes and also prevents dehydration. To perform their functions while being confronted with the physicochemical traumas of the environment, these tissues undergo continual rejuvenation through homeostasis, and, in addition, they must be primed to undergo wound repair in response to injury. The skin's elixir for maintaining tissue homeostasis, regenerating hair, and repairing the epidermis after injury is its stem cells, which reside in the adult hair follicle, sebaceous gland, and epidermis. Stem cells have the remarkable capacity to both self-perpetuate and also give rise to the differentiating cells that constitute one or more tissues. In recent years, scientists have begun to uncover the properties of skin stem cells and unravel the mysteries underlying their remarkable capacity to perform these feats. In this paper, I outline the basic lineages of the skin epithelia and review some of the major findings about mammalian skin epithelial stem cells that have emerged in the past five years.
Does Inflation Vary between Cities

Apart from occasional anecdotal observation, there has been little systematic study of the patterns of local inflation. The strongest theoretical argument is that local price inflation should be no different from national inflation. Alternatively, it has been suggested that spatial price equilibrium is implausible and that spatial price interdependence is more likely. Quarterly data for some sixteen large US urban areas over the period 1950–1980, are analyzed via stochastic time-series models. It is concluded in this paper that, although inflation does vary, if only slightly, between cities and with respect to the nation, in some instances national inflation may fairly represent local inflation.
Formation of a defect-free junction layer by controlling defects due to As/sup +/ implantation

A method of suppressing defects related to knock-on has been developed through the use of a Si/sub 3/N/sub 4/ film as an implementation mask. In MOS devices with LDD structures, junction leakage is caused by the dislocation lines from the sidewall edge. Two requirements are needed to suppress the growth of the dislocation lines: the elimination of stress from the sidewall edge and the elimination of dislocation loops due to As/sup +/ implantation. The growth of dislocation loops is affected by the presence of recoiled oxygen atoms from implantation through SiO/sub 2/ films. However, when a Si/sub 3/N/sub 4/ mask is used as an implantation mask, the amount of recoiled nitrogen atoms is two orders of magnitude lower in comparison to the recoiled oxygen atoms for a SiO/sub 2/ mask, and the dislocation loops disappear during heat treatment. Consequently, defects are not generated and the junction leakage failures due to residual defects disappear. >
The Balance Between Mutators and Nonmutators in Asexual Populations

Mutator alleles, which elevate an individual’s mutation rate from 10 to 10,000-fold, have been found at high frequencies in many natural and experimental populations. Mutators are continually produced from nonmutators, often due to mutations in mismatch-repair genes. These mutators gradually accumulate deleterious mutations, limiting their spread. However, they can occasionally hitchhike to high frequencies with beneficial mutations. We study the interplay between these effects. We first analyze the dynamics of the balance between the production of mutator alleles and their elimination due to deleterious mutations. We find that when deleterious mutation rates are high in mutators, there will often be many “young,” recently produced mutators in the population, and the fact that deleterious mutations only gradually eliminate individuals from a population is important. We then consider how this mutator–nonmutator balance can be disrupted by beneficial mutations and analyze the circumstances in which fixation of mutator alleles is likely. We find that dynamics is crucial: even in situations where selection on average acts against mutators, so they cannot stably invade, the mutators can still occasionally generate beneficial mutations and hence be important to the evolution of the population.
Psychoactive drugs and the risk of injurious motor vehicle crashes in elderly drivers

To determine whether commonly used psychoactive drugs increase the risk of involvement in motor vehicle crashes for drivers > or = 65 years of age, the authors conducted a retrospective cohort study. Data were obtained from computerized files from the Tennessee Medicaid program, driver's license files, and police reports of injurious crashes. Cohort members were Medicaid enrollees 65-84 years of age who had a valid driver's license during the study period 1984-1988 and who met other criteria designed to exclude persons unlikely to be drivers and to ensure availability of necessary study data. There were 16,262 persons in the study cohort with 38,701 person-years of follow-up and involvement in 495 injurious crashes. For four groups of psychoactive drugs (benzodiazepines, cyclic antidepressants, oral opioid analgesics, and antihistamines), the risk of crash involvement was calculated with Poisson regression models that controlled for demographic characteristics and use of medical care as an indicator of health status. The relative risk of injurious crash involvement for current users of any psychoactive drug was 1.5 (95% confidence interval (CI) 1.2-1.9). This increased risk was confined to benzodiazepines (relative risk = 1.5; 95% CI 1.2-1.9) and cyclic antidepressants (relative risk = 2.2; 95% CI 1.3-3.5). For these drugs, the relative risk increased with dose and was substantial for high doses: 2.4 (95% CI 1.3-4.4) for > or = 20 mg of diazepam and 5.5 (95% CI 2.6-11.6) for > or = 125 mg of amitriptyline. Analysis of data for the crash-involved drivers suggested that these findings were not due to confounding by alcohol use or driving frequency. Language: en
Towards Community Discovery in Signed Collaborative Interaction Networks

â€”We propose a framework for discovery of collaborative community structure in Wiki-based knowledge repositories based on raw-content generation analysis. We leverage topic modelling in order to capture agreement and opposition of contributors and analyze these multi-modal relations to map communities in the contributor base. The key steps of our approach include (i) modeling of pair wise variable-strength contributor interactions that can be both positive and negative, (ii) synthesis of a global network incorporating all pair wise interactions, and (iii) detection and analysis of community structure encoded in such networks. The global community discovery algorithm we propose outperforms existing alternatives in identifying coherent clusters according to objective optimality criteria. Analysis of the discovered community structure reveals coalitions of common interest editors who back each other in promoting some topics and collectively oppose other coalitions or single authors. We couple contributor interactions with content evolution and reveal the global picture of opposing themes within the self-regulated community base for both controversial and featured articles in Wikipedia.
Sleep deprivation and surgical performance: a difficult simulation.

IT HAS NOW BEEN 6 YEARS SINCE THE ACCREDITATION COUNCIL FOR GRADUATE MEDICAL EDUCATION implemented the 80-hour workweek restrictions for residents. The academic surgical community remains divided into two camps regarding these reforms. Some still write longingly for ‘‘the way we were’’ where 100+-hour workweeks selected the fittest to survive a surgical career. The others see work-hours restriction as a long overdue reform and one that has had significant positive impact on the surgical profession and its training programs. The first camp may well look to this issue of Surgery, where Lehmann et al present the results of a prospective study examining the effects of sleep deprivation on cognitive and psychomotor performance as support of the ability of trainees and surgeons in practice to maintain surgical performance in the face of fatigue. Unfortunately, this report will not support that conclusion. Even as the authors suggest, this simulated environment is subject to the Hawthorne effect and demonstrates an ability to maintain performance in one area during a moderate 20to 30-min time period in a competitive setting. As they point out, ‘‘the simulator tests are not standardized nor are reference data available.’’ The most significant difficulty in this study is the inability of even validated simulators to simulate the collection of knowledge, skills, and attitudes that represent the performance of a surgeon in a clinical setting. We diminish our standing in the public square when we use such studies to suggest that surgeons are somehow able to resist the effects of normal circadian rhythms common to all other humans. It is disappointing to see continued funding and research efforts focused on sleep deprivation
FACTORS INFLUENCING THE RESPIRATION OF ERYTHROCYTES : I. PRIMITIVE AVIAN ERYTHROCYTES.

1. The oxygen consumption of normal and "primitive red cells" of fowls' blood has been determined at intervals in the course of an anemia produced by the injection of phenylhydrazine. The "primitive red cells" have an oxygen consumption at least twenty to twenty-five times greater than the normal red cells. 2. Suspension of the cells derived from the blood in anemia in sodium chloride solutions of various concentrations has comparatively little effect upon the oxygen consumption of the cells. 3. The red cells from anemic blood are sensitive to variations in the reaction of the medium in which they are suspended. The maximum oxygen consumption, after addition of a saline solution containing variable amounts of acid to the blood, took place at pH 7.75. They appeared somewhat more sensitive to variations on the acid side of this reaction than on the alkaline. 4. Addition of glucose to the medium increased the oxygen consumption of the cells. Their metabolism in a physiological saline solution containing 0.6 per cent of glucose was 15 per cent higher than in one in which no glucose was present. 5. Certain amino acids in low concentrations had little effect on oxygen consumption, though at higher concentrations some of them definitely diminished it.
Concentration of measure inequalities for compressive toeplitz matrices with applications to detection and system identification

In this paper, we derive concentration of measure inequalities for compressive Toeplitz matrices (having fewer rows than columns) with entries drawn from an independent and identically distributed (i.i.d.) Gaussian random sequence. These inequalities show that the norm of a vector mapped by a Toeplitz matrix to a lower dimensional space concentrates around its mean with a tail probability bound that decays exponentially in the dimension of the range space divided by a factor that is a function of the sample covariance of the vector. Motivated by the emerging field of Compressive Sensing (CS), we apply these inequalities to problems involving the analysis of high-dimensional systems from convolution-based compressive measurements. We discuss applications such as system identification, namely the estimation of the impulse response of a system, in cases where one can assume that the impulse response is high-dimensional, but sparse. We also consider the problem of detecting a change in the dynamic behavior of a system, where the change itself can be modeled by a system with a sparse impulse response.
Study of stability and power quality of parallel grid-connected inverters for vehicle-to-grid application

The number of distributed energy resources are increasing in modern power systems. Vehicle-to-grid power transfer is envisioned to become another type of distributed energy resource and support energy needs of the grid under various circumstances. This paper investigates the stability and power quality of a parallel grid-connected inverter system for vehicle-to-grid application using modeling and simulation. The grid-connected inverter includes a three-phase voltage source inverter, LCL output filter, and closed-loop control. In this research, stability analysis of grid-connected inverters is investigated by assessing closed loop poles of system. The dynamic simulation results obtained from MATLAB Simulink are used to demonstrate the importance of controller gain and grid conditions on system stability and power quality for a parallel grid-connected inverter system.
Barrier Activity in Candida albicans Mediates Pheromone Degradation and Promotes Mating

Mating in Candida albicans and Saccharomyces cerevisiae is regulated by the secretion of peptide pheromones that initiate the mating process. An important regulator of pheromone activity in S. cerevisiae is barrier activity, involving an extracellular aspartyl protease encoded by the BAR1 gene that degrades the alpha pheromone. We have characterized an equivalent barrier activity in C. albicans and demonstrate that the loss of C. albicans BAR1 activity results in opaque a cells exhibiting hypersensitivity to alpha pheromone. Hypersensitivity to pheromone is clearly seen in halo assays; in response to alpha pheromone, a lawn of C. albicans Deltabar1 mutant cells produces a marked zone in which cell growth is inhibited, whereas wild-type strains fail to show halo formation. C. albicans mutants lacking BAR1 also exhibit a striking mating defect in a cells, but not in alpha cells, due to overstimulation of the response to alpha pheromone. The block to mating occurs prior to cell fusion, as very few mating zygotes were observed in mixes of Deltabar1 a and alpha cells. Finally, in a barrier assay using a highly pheromone-sensitive strain, we were able to demonstrate that barrier activity in C. albicans is dependent on Bar1p. These studies reveal that a barrier activity to alpha pheromone exists in C. albicans and that the activity is analogous to that caused by Bar1p in S. cerevisiae.
A Fiber Optic Binary Switch for Aircraft Application

An optic binary switch for aircraft application is investigated. A fiber Fabry-Perot interferometer (FFPI) bonded to a cantilever exhibits excellent linearity as a force sensor. White light inteferometry (WLI) system is used to monitor the elongation of FFPI. With proper threshholding, the system produces a binary output.
The use of autologous blood in open-heart surgery.

A fairly simple method for obtaining from two to four units of fresh autologous whole blood and as many as six units of autologous fresh, frozen plasma is described. The only special equipment necessary is a refrigerated centrifuge. The procedure is well tolerated by the patients. The need for heterologous units of blood is diminished or entirely eliminated.
High power laser and explosive driven shock wave characterization in solids using fiber optic probes

Shock wave transmission and propagation in solid media is studied using fiber optic pressure and velocity probes. Shock waves are generated in two experiments using a high power laser facility as well as conventional explosives. Shock wave properties including peak overpressure, mass velocity, shock duration, impulse, arrival time and shock velocity are characterized using fiber tip interferometric displacement sensors and Fabry-Perot pressure sensors. Measurements are conducted in polymethyl methacrylate and limestone. The probes recorded shock pressures up to 0.1 GPa (1 kbar). Measurements from the fiber optic sensors are shown to be in close agreement with measurements from an electrical sensor based on a Dremin loop.
Effects of obesity and ovarian steroids on insulin secretion and removal in sheep

The interactive effects of sex steroids and obesity on glucose metabolism and pancreatic secretion and organ removal of insulin were determined in multicatheterized lean and obese sheep by multiplying venoarterial concentration differences by plasma flows. Ovariectomized lean and dietary obese ewes received implants of progesterone and estradiol-17 beta that produced plasma concentrations of each equivalent to those during either anestrus (low progesterone), diestrus or pregnancy (high progesterone), or estrus (high estradiol). Sheep were exposed to each of the three steroid treatments for 2 days and fasted overnight before blood samples were collected for 5 h before (basal) and 90 min after injecting glucose (200 mg/kg) to simulate an intravenous glucose tolerance test (IVGTT). Regardless of steroid treatment, pancreatic secretory (18 vs. 5 mU/min) and hepatic (10 vs. 2 mU/min) and hindquarters (1.8 vs. 0.5 mU/min) removal rates of insulin in the basal state were greater (P less than 0.005) in obese than lean sheep. Obese sheep had greater (P less than 0.025) basal hepatic glucose output (66 vs. 47 mg/min) and similar hindquarters glucose removal (37 vs. 32 mg/min) as lean sheep even though arterial concentrations of insulin were fourfold higher (25 vs. 6 microU/ml; P less than 0.01) in the obese sheep. High progesterone increased (P less than 0.05) basal hepatic insulin removal in obese sheep. High progesterone and high estradiol increased insulin but decreased (P less than 0.05) glucose removal in hindquarters of obese sheep in the basal state. High progesterone potentiated significantly glucose-induced hyperinsulinemia in obese sheep, whereas high estradiol suppressed hepatic insulin removal but increased the removal of insulin by hindquarters during glucose stimulation in the obese sheep. We concluded that excessive insulin secretion, not decreased insulin removal, maintains the basal hyperinsulinemia in moderately obese sheep and that the progesterone-to-estradiol ratio has marked and divergent effects on insulin and glucose metabolism in individual tissues of sheep both in the basal state and during an IVGTT.
Differential Item Functioning Across Race in Aging Research: An Example Using a Social Support Measure

When conducting clinical assessments in older adults of different races, it is important for a clinician to feel confident that his/her instruments work equivalently well for all races. To explore the ability of instruments to measure constructs equally well across older adults of different races, we conducted differential item functioning (DIF) analysis on the Interpersonal Support Evaluation List (ISEL-12). Eight ISEL items displayed negative DIF, indicating their lower endorsement among Blacks, Hispanics, and in some cases Asians, compared with Whites. Two items displayed positive DIF, suggesting higher endorsement on these items by Blacks and Hispanics than Whites. Once DIF was accounted for, however, only Asians endorsed lower levels of social support than the White reference group. Potential mechanisms of these differences and suggestions for addressing DIF when conducting clinical assessments were explored.
The polarization of 5·3 Mev protons elastically scattered from helium

The polarization of 5·32 Mev protons elastically scattered by helium has been measured by a double scattering experiment with a polarizer-analyzer arrangement. The first scattering was selected to take place in the region of the P1/2 energy state of Li5 and the second scattering at theP3/2 state. The polarization after the first scattering at an angle of 55° (c.m.) has been measured to beP1= 0·40±0·05 and is positive in agreement with the calculated polarization using the phase shift values obtained from the analysis of differential scattering cross-section data. (The positive direction is defined by the vector product between the scattered proton wave vector and the incident proton wave vector.) A preliminary experiment with poor geometry and an average scattering angle of 90° (c.m.) also gave results which agree with the calculations. The large splitting of theP1/2 andP3/2 states and the very broad width of theP1/2 level are therefore confirmed.
Underpotential Deposition of Tl on (111)-Textured Au: In Situ Stress and Nanogravimetric Measurements

The surface stress associated with the underpotential deposition (upd) of thallium (Tl) on (111)-textured Au is examined, using the wafer curvature method in acidic perchlorate supporting electrolyte. The process is also examined by independent nanogravimetric measurements using an electrochemical quartz crystal nanobalance (EQCN). We observe a sweep rate dependence for both the individual voltammetric waves and stress response, which we attribute to kinetically controlled surface alloying that occurs only at low coverage. Similar behavior has been reported for Pb upd on (111)-textured Au, but the kinetics for Tl are considerably slower and are very sensitive to the defect density of the Au(111) surface. At high coverage, a full Tl monolayer is formed; however, a dealloying step is required prior to completion of the monolayer. The stress hump that is coincident with the last voltammetric wave appears to be caused by the formation and removal of the surface alloy. This is confirmed by long-term potentiost...
Long-Lasting Changes in Morphine-Induced Locomotor Sensitization and Tolerance in Long-Evans Mother Rats as a Result of Periodic Postpartum Separation from the Litter: A Novel Model of Increased Vulnerability to Drug Abuse?

Daily postpartum separations from the litter produce enduring changes in anxiety and sensitivity to the antinociceptive effects of morphine in Long-Evans dams. We tested whether postpartum experience alters sensitivity to the effects of morphine on locomotor activity. Dams were tested 4-6 weeks after their pups were weaned, and had one of the following backgrounds: daily separation from the litter on postpartum days 2-14 for either 3 h (prolonged separation-LS) or 15 min (brief separation-BS), or no separation (nonhandled control-NH). After 2 consecutive days (B1-2) of baseline activity measurements, subjects were tested daily after s.c. injections of either morphine (10 mg/kg) or saline for 7 days and again on day 10. Beginning 5 days later, saline and 1.0-10 mg/kg of morphine were tested in all dams. On B1, LS and BS dams habituated slower than NH controls, yielding higher horizontal counts. LS dams failed to habituate across baseline days and were more active than other dams on B2. Sensitization, a progressive increase in horizontal activity, was more rapid and robust in LS and BS dams compared to NH animals. LS was the only group that developed tolerance to morphine-induced decreases in vertical activity. In LS dams with the history of morphine treatment, injection of saline resulted in higher horizontal activity and center time compared to saline-treated counterparts, indicative of conditioning. Among animals with a history of saline treatment, LS dams were more sensitive to morphine challenges than BS and NH dams. As a result of the robust and long-lasting increases in the ability of morphine to induce behavioral sensitization in litter-separated dams, periodic postpartum separation may represent a new animal model of increased vulnerability to substance abuse.