cssi/SciSciGPT-SciSciNet huggingface dataset:
A Modelling Framework for Describing the Corrosion Fatigue Behaviour of Carbon Steel Pipelines and Risers

The fatigue performance of pipeline or riser girth welds is often a critical factor during design. Under corrosive conditions the detrimental influence of an environment on anticipated fatigue lives needs to be taken into account. Fatigue design codes provide advice for the case of loading in seawater at typical wave frequencies, but in other environments, or at other cyclic loading frequencies, the required approach is less certain, and laboratory testing is often needed to provide suitable guidance. In addition to the time and expense of such an exercise, in some cases there are physical limits to the nature of data that such programmes can provide. The provision of data associated with very low cyclic loading frequencies is one such case, as in this instance the time taken for each test becomes unmanageable. This leads to the need for extrapolation of test data into the region of interest, for instance by carrying out tests at either a higher cyclic loading frequency, or a higher stress range, than that anticipated in service. Such extrapolation requires careful consideration in order to avoid potential non-conservatism. It is suggested that the availability of a model which accounted for the influence of these two key parameters (frequency and stress range) would greatly improve confidence when extrapolation is needed, and more broadly would provide a rational basis for designing experimental testing programmes and applying determined data to pipeline design. Such a model should be based on a description of the perceived underlying mechanisms of a material’s interaction with the environment. This paper provides a review of relevant test data and describes the basis for such a model. A generalised framework is developed and fitted to numerous published test data for carbon steels in seawater or sour environment.Copyright © 2011 by ASME
Accelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET-MR: phantom and patient studies.

Purpose: Degradation of image quality caused by cardiac and respiratory motions hampers the diagnostic quality of cardiac PET. It has been shown that improved diagnostic accuracy of myocardial defect can be achieved by tagged MR (tMR) based PET motion correction using simultaneous PET-MR. However, one major hurdle for the adoption of tMR-based PET motion correction in the PET-MR routine is the long acquisition time needed for the collection of fully sampled tMR data. In this work, the authors propose an accelerated tMR acquisition strategy using parallel imaging and/or compressed sensing and assess the impact on the tMR-based motion corrected PET using phantom and patient data. Methods: Fully sampled tMR data were acquired simultaneously with PET list-mode data on two simultaneous PET-MR scanners for a cardiac phantom and a patient. Parallel imaging and compressed sensing were retrospectively performed by GRAPPA and kt-FOCUSS algorithms with various acceleration factors. Motion fields were estimated using nonrigid B-spline image registration from both the accelerated and fully sampled tMR images. The motion fields were incorporated into a motion corrected ordered subset expectation maximization reconstruction algorithm with motion-dependent attenuation correction. Results: Although tMR acceleration introduced image artifacts into the tMR images for both phantom and patient data,more » motion corrected PET images yielded similar image quality as those obtained using the fully sampled tMR images for low to moderate acceleration factors (<4). Quantitative analysis of myocardial defect contrast over ten independent noise realizations showed similar results. It was further observed that although the image quality of the motion corrected PET images deteriorates for high acceleration factors, the images were still superior to the images reconstructed without motion correction. Conclusions: Accelerated tMR images obtained with more than 4 times acceleration can still provide relatively accurate motion fields and yield tMR-based motion corrected PET images with similar image quality as those reconstructed using fully sampled tMR data. The reduction of tMR acquisition time makes it more compatible with routine clinical cardiac PET-MR studies.« less
Fundamental optical properties of linear and cyclic alkanes: VUV absorbance and index of refraction

VUV absorbance and index of refraction data for a series of linear and cyclic alkanes have been collected in order to understand the relationship between the electronic excitation wavelength (or absorbance edge), index of refraction, and molecular structure. The absorbance edge and index for a homologous series of both linear and cyclic alkanes increase with increasing carbon number. The optical properties of complex cycloalkanes do not vary predictably with increasing carbon number but instead depend on variations in the hydrocarbon structure in addition to hydrocarbon size. An understanding of the fundamental optical properties of this class of compounds is directly applicable to the identification of a high index and low-absorbance fluid for 193 nm immersion lithography.
Complications of transradial catheterization

Cardiac catheterization via the transradial approach has increased in the United States over the past few years; however, wide-scale adoption still lags in comparison to many international health care systems. Transradial catheterization has a unique set of complications and risks that each operator must appreciate. Radial artery spasm and radial artery occlusion are the most common complications, while bleeding complications such as hematomas and perforations are much less frequent. Each of these issues can be managed successfully with minor changes to one's practice. In this review of the current state of the art, the reader will develop an appreciation for the prevalence of each of the common complications as well as the less common, but potentially highly morbid, events. Throughout this evidence-based review, practical prevention strategies and specific treatment pathways are described for each issue that is covered.
Structural biology: A protein engagement RING.

The mechanistic details of the attachment of a small protein, ubiquitin, to other proteins are unclear. Crystal structures of the complexes formed by the E2–ubiquitin and RING E3 enzymes offer new insights. See Article p.115 Post-translational modification of proteins by ubiquitin and its homologues is important for many physiological processes. Ubiquitin is transferred to target proteins from a thioester complex with a ubiquitin-conjugating enzyme (E2) in a step catalysed by a ubiquitin ligase (E3). In this study, Ronald Hay and colleagues present the crystal structure of a RING type E3 ligase bound to ubiquitin-loaded E2. The structure reveals how ubiquitin binding to E2 leads to changes in the catalytic site, priming it for catalysis by the E3 enzyme. The mechanisms proposed here are likely to be conserved among other ubiquitin-conjugating enzymes.
An automated drusen detection system for classifying age-related macular degeneration with color fundus photographs

We present a system of automated drusen detection from color fundus photographs with our ultimate goal being to automatically assess the risk for the development of Age-related Macular Degeneration (AMD). Our system incorporates learning based drusen detection and includes fundus image analysis techniques for image denoising, illumination correction and color transfer. In contrast to previous work, we incorporate both optimal color descriptors and robust multiscale local image descriptors in our drusen detection process. Our system was evaluated with color fundus photographs from two AMD clinical studies [1, 2]. By comparing our results to those obtained via manual drusen segmentation, we show that our system outperforms two state-of-the-art techniques.
Evaluating the comparability of two measures of lexical diversity

Abstract Language practitioners and others increasingly rely on computerized assessments of large samples of written texts. In order to provide teachers and researchers with useful knowledge, new, more accurate metrics must be developed to aid in these assessments. One common aspect of such assessments is lexical diversity, or the displayed range of diversity in vocabulary. The vocd program and the metric it develops, VOCD-D, have become popular options for researchers attempting to assess lexical diversity. However, researchers have argued that this metric is in fact a complex approximation of a more direct and less variable measure derived from probability sampling, known as HD-D. Using a data set of essays written by Chinese, Japanese, Korean, and native English-speakers drawn from the International Corpus Network of Asian Learners of English, this research investigates that approximation by comparing correlations across L1 and L2 writers. In all cases, the correlations between HD-D and VOCD-D are very high, suggesting that the similarity between these metrics is indeed a product of their statistical mechanisms.
Last Glacial Maximum's effect on the Walker circulation

Over the tropical Pacific Ocean the Walker circulation is an atmospheric flow pattern that runs parallel to the equator, with ascending motion over the western Pacific and a horizontal tropospheric return flow that carries air back to the east. Scientists predict that the Walker circulation will weaken with global warming through a mechanism known as the Held, Soden, and Vecchi (HSV) mechanism. According to this system, as surface ocean temperatures increase, atmospheric humidity and precipitation rates will also increase. Conversely, as surface ocean temperatures decrease, atmospheric humidity and local precipitation will decrease. Humidity levels change much more easily than precipitation rates; as temperatures rise, this disparity leads to a decrease in vertical air motion as the atmosphere tries to maintain a balanced flow of air. If temperatures fall, vertical air motion will increase. Although the HSV mechanism is a robust feature of climate models, its observed sensitivity to changing temperatures remains uncertain.
Verification of Strip Drawing Analysis Using New Sapphire Dies

In this paper a simple analysis of strip drawing, including the influence of back tension on drawing force, is developed and verified by experiments using new sapphire dies and traditional carbide dies. The simple analysis provides a good estimate of forces and pressures acting on the dies and would be considered as a quick alternate to the solutions based on the more expensive finite element methods. It is found from experiments that friction is less for sapphire compared with carbide [1]. Although sapphire is an attractive die material because it fulfills certain wear requirements and has low friction, it is a brittle material. In order to withstand cold metal drawing, it should be supported by a high-strength steel holder. Such design considerations are also presented to facilitate the use of sapphire dies in practical applications.
Calculation of the Scattering Constant from the Theory of Multiple Scattering

The expressions for the mean spatial and projected angles of multiple scattering are obtained using the distribution function for multiple scattering derived by Nigam, Sundaresan and Wu, and compared with those of Moli\`ere. It is shown that Moli\`ere's calculations involve the approximation of ${\ensuremath{\chi}}_{c}\ensuremath{\surd}B\ensuremath{\rightarrow}0$. The distribution function of Nigam et al. is found to give correction terms which are proportional to powers of ${\ensuremath{\chi}}_{c}\ensuremath{\surd}B$ and ${\ensuremath{\chi}}_{c}\ensuremath{\surd}B\mathrm{ln}(\frac{\ensuremath{\pi}}{{\ensuremath{\chi}}_{c}\ensuremath{\surd}B})$.
An enexpensive pulser for the adjustment of subnanosecond walk in timing circuits

An inexpensive pulse generator capable of providing narrow (< 10 ns fwhm; ± 1.2 V) pulses is described. In this application, the pulser is used to adjust the walk in calibrating amplitude and rise time compensated (ARC) timing units. A walk of 22 ps between 0 dB and −40 dB with a maximum spread of 220 ps over the full range is observed.
Religious exemptions: brain death and Jewish law.

"We maintain our position, however, that total and irreversible cessation of all brain function, as determined by the Harvard criteria, is equivalent to total de struction of the brain and, hence, tantamount to functional or physiological decap itation, which in Judaism is equated with death."1 "We have been requested to declare our views, (according to) da'as Torah (Jewish Law) with respect to the transplantation of a heart or other organs for the benefit of a sick person whose life is in danger, at a time when the heart of the donor is beating, and its entire brain, including the brain stem, is not functioning at all, which is known as "brain death": It is our view that it is absolutely not
A non-homogeneous, symmetric contact projective structure

We construct a non-homogeneous contact projective structure which is symmetric from the point of view of parabolic geometries.
Quality of life and social outcomes in adults with congenital heart disease living in rural areas of Kentucky

As revealed by a quality-of-life survey done in a small rural Kentucky cohort, adults who live in rural areas who have congenital heart disease have a relatively poor health-related quality of life and face unique challenges in gaining employment, maintaining health insurance, and overcoming the perceived childhood stigma of being "different."
The use of proteolytic enzymes to determine the location of histones in chromosomal substructures

Abstract We have observed that three proteolytic enzymes with widely different specificities produce a very similar pattern in terms of the order of digestion of the various histone fractions in chromatin. Histone H2A is most resistant to proteolytic attack by trypsin, chymotrypsin, or Pronase. H2B is next most resistant, followed by H3. Histone H1 is least resistant and is rapidly hydrolyzed by each of these enzymes. The behavior of histone H4 differs for the various enzymes. It is as resistant as H2A to digestion by trypsin and chymotrypsin but is readily hydrolyzed by Pronase. A comparison of the rates of digestion of the various histone fractions in chromatin with the rates in a DNA-free histone mixture and a study of the degradation products which result from digestion indicate that histone conformation and histone-histone and DNA-histone interactions are all involved in protecting histones from attack by proteolytic enzymes. From the results of our studies we have concluded that histones H1 and H3 are located in superficial positions of the chromosomal substructures (or nu bodies) while H2A is buried inside. Since histone H2B is relatively resistant to digestion but more readily degraded in chromatin than in a DNA-free histone mixture, it is difficult to determine its chromosomal location. Histone H4 behaves as if a large portion of the molecule is located in the major groove of the DNA helix.
Unpacking Detracking: When Progressive Pedagogy Meets Students’ Social Worlds

Despite heated debate over detracking, little research exists on how the reform plays out in the classroom. This article, based on a year-long interpretive study of a detracked ninth-grade program at a diverse urban high school, focuses on the encounter between the “official” practices of the detracked classrooms under study and the “unofficial” social worlds of the students taking part in those practices. The author describes how aspects of the overall school context framed and permeated students’ interactions in their detracked classes, at times leading to a reiteration of the very inequalities that detracking was designed to address.
Inter-specific variation in avian responses to human disturbance

Summary 1. Increasing urbanization and recreational activities around and within biodiversity hotspots require an understanding of how to reduce the impacts of human disturbance on more than a single species; however, we lack a general framework to study multiple species. One approach is to expand on knowledge about the theory of anti-predator behaviour to understand and predict how different species might respond to humans. 2. We reviewed the literature and found that only 21% of studies that used a behavioural approach to study human disturbance focused on multiple species. These studies identified a number of potential predictive variables. 3. We developed a simulation model that investigates interspecific variation in different parameters of disturbance with variation in human visitation. We found that fitness-related responses, such as the quantity of food consumed by a species, are relatively sensitive to the distance at which animals detect humans, the frequency of disturbance by humans and the interaction of these factors, but are less sensitive to other characteristics. 4. We examined avian alert distance (the distance animals first orientated to an approaching threat, a proxy for detection distance) across 150 species, controlling for phylogenetic effects. We found that larger species had greater alert distances than smaller species, which could increase local spatial and temporal limitations on suitable habitat with increasing human visitation. 5. Synthesis and applications . Our results suggest that body size could be a potential predictor of responses to human disturbance across species, and could be used by managers to make conservation decisions regarding levels of human visitation to a protected site. We suggest that three things are essential to develop predictive models of how different species will respond to human disturbance. First, multiple indicators of disturbance should be studied to select those with lower intraspecific variation for a given study system. Secondly, the species-specific nature of responses should be identified. Thirdly, life history, natural history and other correlates with these species-specific responses must be assessed.
Influenza Pandemic Epidemiologic and Virologic Diversity: Reminding Ourselves of the Possibilities

The 2009 influenza A (H1N1) pandemic serves as a stark reminder of the inherently unpredictable nature of influenza virus. Although most planning centered on the potential emergence of a wholly new influenza A subtype of avian origin causing the next pandemic, a very different scenario occurred: a mammalian-adapted reassortant drift variant of a familiar subtype caused the first pandemic of the 21st Century. This pandemic also reminds us of the variability possible with respect to the epidemiology of pandemic influenza, the effects of population immunity to novel influenza strains on age-specific morbidity and mortality, and the potential importance of domestic animals in the ecology of influenza and the formation of new virus strains with pandemic potential. Future pandemic preparedness planning should include addressing gaps in influenza surveillance among nonhuman mammalian species at the animal human interface as part of pandemic risk assessment.
DaTA -- Data-Transparent Authentication Without Communication Overhead

With the development of Internet computing techniques, continuous data streams from remote sites are commonly used in scientific and commercial applications. Correspondingly, there is increasing demand of assuring the integrity and authenticity of received data streams. Existing strategies of assuring data integrity and authenticity mainly use message authentication codes (MAC) generated on data blocks and transfer the MAC to the receiver for authentication through either out of band communication or in band communication. Transferring the MAC via out of band communication inevitably introduces communication overhead and additional complexity to synchronize the out of band communication with the data communication. Transferring the MAC via in band channel can be achieved by either appending the MAC to the original data or embedding the MAC into the original data, which would either incur communication overhead or change the original data. It would be desirable to be able to authenticate the stream data without any communication overhead and changing the original data at the same time. To deal with data packet or block loss, many of existing stream data authentication schemes rely on hash chaining, the current usage of which results in uncertainty in authenticating the subsequent data blocks once the first data packet or block loss is detected. In this paper, we propose a novel application layer authentication strategy called DaTA. This authentication scheme requires no change to the original data and causes no additional communication overhead. In addition, it can continue authenticating the rest of data stream even if some data loss has been detected. Our analysis shows that our authentication scheme is robust against packet loss and network jitter. We have implemented a prototype system to evaluate its performance. Our empirical results show that our proposed scheme is efficient and practical under various network conditions
A comparison of fatigue life prediction methodologies for rotorcraft

Because of the current U.S. Army requirement that all new rotorcraft be designed to a 'six nines' reliability on fatigue life, this study was undertaken to assess the accuracy of the current safe life philosophy using the nominal stress Palmgrem-Miner linear cumulative damage rule to predict the fatigue life of rotorcraft dynamic components. It has been shown that this methodology can predict fatigue lives that differ from test lives by more than two orders of magnitude. A further objective of this work was to compare the accuracy of this methodology to another safe life method called the local strain approach as well as to a method which predicts fatigue life based solely on crack growth data. Spectrum fatigue tests were run on notched (k(sub t) = 3.2) specimens made of 4340 steel using the Felix/28 tests fairly well, being slightly on the unconservative side of the test data. The crack growth method, which is based on 'small crack' crack growth data and a crack-closure model, also predicted the fatigue lives very well with the predicted lives being slightly longer that the mean test lives but within the experimental scatter band. The crack growth model was also able to predict the change in test lives produced by the rainflow reconstructed spectra.
The Preparation of InAsSb/InSb SLS and InSb Photodiodes by MOCVD

Infrared absorption and photoluminescence have been demonstrated for InAs1-xSbx/InSb strained-layer superlattices (SLS's) in the 8-15 μm region for As content less than 20%. This extended infrared activity is due to the type II heterojunction band offset in these SLS's. The preparation of the first MOCVD grown p-n junction diode was achieved by using dimethyltellurium as an n-type dopant. Several factors, such as background doping and dopant profiles affect the performance of this device. InSb diodes have been prepared using tetraethyltin. The resulting current-voltage characteristics are improved over those of diodes grown previously using dimethyltellurium. Doping levels of 8x1015 to 5x1018cm−3 and mobilities of 6.7x104 to 1.1x104 cm2/Vs have been measured for Sn doped InSb. SLS diode structures have been prepared using Sn and Cd as the dopants. Structures prepared with p-type buffer layers are more reproducible.
Factors in Bargaining That Affect Negotiation and Mediation Success

The bargaining procedures and protocols that structure negotiations can differ as dramatically as the organizational structures of the groups involved in negotiations. These features of the bargaining environment can range in formality from those set by law or custom to those adopted on an ad hoc basis. In each bargaining setting, the presence or absence of certain features can affect the likelihood of bargaining progress. These includes: The existence of both common and competitive interests linking the groups; How groups are recognized as participants in a dispute; The balance of power between the competing groups; The frequency of negotiations; The number of bargaining groups: The existence of bargaining deadline; The existence of binding agreements to conclude formal negotiations.
Clinical and Genetic Correlates of Aldosterone-to-Renin Ratio and Relations to Blood Pressure in a Community Sample

Aldosterone:renin ratio (ARR) is used to screen for hyperaldosteronism. Data regarding correlates of ambulatory ARR in the community and its relation to hypertension incidence are limited. We defined clinical correlates of ARR, determined its heritability, tested for association and linkage, and related ARR to blood pressure (BP) progression in nonhypertensive individuals among 3326 individuals from the Framingham Heart Study (53% women; mean age: 59 years). Ambulatory morning ARR (serum aldosterone and plasma renin concentrations) were related to clinical covariates, genetic variation across the REN locus, a 10-cM linkage map, and among nonhypertensive participants (n=1773) to progression of >or=1 Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure BP category (optimal: or=140/90 mm Hg), or incident hypertension (systolic BP: >or=140 mm Hg, diastolic BP: >or=90 mm Hg, or use of antihypertensive treatment). ARR was positively associated with age, female sex, untreated hypertension, total/high-density lipoprotein cholesterol ratio, hormone replacement therapy, and beta-blocker use, but negatively associated with angiotensin-converting enzyme inhibitor and diuretic use. ARR was heritable (h(2)=0.40), had modest linkage to chromosome 11p (logarithm of the odds: 1.89), but was not associated with 17 common variants in REN (n=1729). On follow-up (mean: 3 years), 607 nonhypertensive individuals (34.2%) developed BP progression, and 283 (16.0%) developed hypertension. Higher baseline logARR was associated with increased risk of BP progression (odds ratio per SD increment: 1.23; 95% CI: 1.11 to 1.37) and hypertension incidence (odds ratio per SD increment: 1.16; 95% CI: 1.00 to 1.33). ARR is a heritable trait influenced by clinical and genetic factors. There is a continuous gradient of increasing risk of BP progression across ARR levels in nonhypertensive individuals.
Corporate governance practices, CEO characteristics and firm performance

This paper examines the link between firm performance, CEO characteristics and changes in corporate governance practices using an unbalanced panel of 1721 firms from 1980 to 1995. This paper provides the stylized facts about corporate governance practices and details how governance practices have evolved over time. By 1995, the majority of firms had implemented differing types of charter amendments, poison pills or other governance provisions that are potentially harmful to shareholders. Most firms have adopted multiple and even redundant governance provisions. Shareholders are more likely to approve an increase in the power of the boards of directors of better performing firms, while the boards of poorly performing firms are much more likely to initiate governance changes, such as poison pills, that circumvent shareholder approval. I find no relationship between CEO age, tenure or compensation and governance changes.
The Effect of Sanctions on Police Misconduct

Police disciplinary systems are predicated on the notion of deterrence, particularly that officers more severely sanctioned for misconduct will be less likely to repeat those behaviors compared with less severely or unsanctioned officers. Using retrospective, longitudinal data from a large police department in the northeastern United States, we explore whether this fundamental assumption of police disciplinary systems is supported. Specifically, we examine both the likelihood and timing of complaints filed against officers who had obtained at least one complaint in their career that was sustained (i.e., upheld in an investigation), and compare outcomes of sanction severity on future sustained complaints. The results demonstrate that while a few demographic and complaint characteristics significantly affect the likelihood and timing of future misconduct in expected ways, officers who received more severe sanctions were actually more likely to obtain an additional sustained complaint when compared with nons...
Genetic and Biochemical Characterization of the F-ATPase Operon from Streptococcus sanguis 10904

Oral streptococci utilize an F-ATPase to regulate cytoplasmic pH. Previous studies have shown that this enzyme is a principal determinant of aciduricity in the oral streptococcal species Streptococcus sanguis and Streptococcus mutans. Differences in the pH optima of the respective ATPases appears to be the main reason that S. mutans is more tolerant of low pH values than S. sanguis and hence pathogenic. We have recently reported the genetic arrangement for the S. mutans operon. For purposes of comparative structural biology we have also investigated the F-ATPase from S. sanguis. Here, we report the genetic characterization and expression in Escherichia coli of the S. sanguis ATPase operon. Sequence analysis showed a gene order of atpEBFHAGDC and that a large intergenic space existed upstream of the structural genes. Activity data demonstrate that ATPase activity is induced under acidic conditions in both S. sanguis and S. mutans; however, it is not induced to the same extent in the nonpathogenic S. sanguis. Expression studies with an atpD deletion strain of E. coli showed that S. sanguis-E. coli hybrid enzymes were able to degrade ATP but were not sufficiently functional to permit growth on succinate minimal media. Hybrid enzymes were found to be relatively insensitive to inhibition by dicyclohexylcarbodiimide, indicating loss of productive coupling between the membrane and catalytic subunits.
Evidence for an immunological and functional relationship between superoxide dismutase and a high molecular weight osteoclast plasma membrane glycoprotein.

Large multinucleated osteoclasts are the major cells responsible for bone breakdown and have been reported to produce high levels of superoxides which may contribute to the process of bone resorption (Key et al.: J Bone and Mineral Res 4 [suppl. 1]:S206, 1989). Osteoclasts also possess high levels of superoxide dismutase, a protective enzyme capable of converting toxic superoxides to less toxic H2O2 (Fridovich: J Biol Chem 264:7761–7764, 1989). The amino acid sequence of manganese and/or iron superoxide dismutase has a conserved region which exhibits substantial homology with a fragment obtained from a high molecular weight osteoclast surface marker glycoprotein which is reactive with monoclonal antibody 121F. In this report, evidence is presented substantiating immunological, biochemical, and functional similarities between the osteoclast membrane antigen recognized by the 121F monoclonal antibody and superoxide dismutase. Western blot and immunoprecipitation studies show that a monospecific polyclonal antibody generated against immunoaffinity purified antigen is cross-reactive with superoxide dismutase. Both the antigen and a high molecular weight superoxide dismutase activity have been detected in osteoclast plasma membrane preparations. The levels of superoxide dismutase activity and the membrane antigen have been found to correlate in antigen depletion studies and in western blots probing osteoclasts and closely related marrow-derived giant cells. Moreover, regions of osteoclast superoxide dismutase activity identified by electrophoretic zymogram analysis have been shown by gel electrophoresis and western blots to contain the high molecular weight antigen, or complexes of the antigen with the 121F monoclonal antibody when these were premixed prior to nondenaturing electrophoresis. It is proposed that the osteoclast plasma membrane possesses a high molecular weight superoxide dismutase activity. Furthermore, it appears that this activity is associated with the osteoclast antigen recognized by the 121F monoclonal antibody.
Knowledge about the initial presentation of smallpox among emergency physicians in Washington, DC.

Objectives To assess the current knowledge of full-time emergency physicians in Washington, DC, regarding the initial diagnosis of smallpox and the initial care of the patient with smallpox. Methods A written true/false test was prepared based on information accessed from the current Centers for Disease Control and Prevention (CDC) Web site on smallpox. The 20-question test was administered to full-time emergency physicians practicing emergency medicine in all seven adult civilian hospitals in Washington, DC. Results The overall response rate was 81% (52 of the 64 eligible full-time emergency physicians). The average score was 59% correct. The facts most likely to be known were 1) that the symptoms of smallpox begin with a two- to four-day prodrome of fever and myalgia (before the appearance of any rash), 2) that no antiviral treatment is of more proven value than vaccination of contacts, and 3) that a person with smallpox may be contagious before any rash appears (average, 90% correct). The facts least likely to be known were 1) that when dealing with a known case of smallpox, fit-tested N95 masks are not needed by treating personnel if they have been vaccinated; 2) that the rash of smallpox begins with 24-48 hours of flat, erythematous macules (not papules or vesicles); and 3) that very typically the rash of smallpox begins in the mouth (average, 22% correct). Conclusions Some facts from the current CDC Web site on smallpox are known by a large majority of full-time emergency physicians in Washington, DC, whereas questions based on other facts were answered incorrectly by a majority of the physicians tested.
Mechanistic Modeling of Zircaloy Deformation and Fracture in Fuel Element Analysis

A review is given of the comprehensive model developed in the 1960's at the Bettis Atomic Power Laboratory to explain the creep of Zircaloy during neutron irradiation and applied to fuel element analysis and design. The in-pile softening observed at low stresses was hypothesized to be due to a combination of the growth-directed Roberts-Cottrell yielding creep originally proposed for ..cap alpha..-uranium and the formation of point defect loops preferentially on certain planes in response to the applied stress, with the second process being of relatively greater importance. The in-pile hardening observed at high stresses (or strain-rates) was proposed to be due to the cutting by dislocations of radiation-produced obstacles. In this stress (strain-rate) region, in-pile behavior was proposed to be identical to post-irradiation behavior. At intermediate stresses (strain-rates) a mechanism of radiation-enhanced climb around obstacles was suggested as being rate controlling. As the stress is decreased, the climb process becomes easier and the rate was then predicted to be controlled by glide at a flow stress characteristic of unirradiated, annealed material, where radiation-enhanced diffusion enabled climbing around the normal strain-hardening obstacles. At still lower stresses, this glide process became negligibly slow compared with the growth-connected creep mechanism which was presumedmore » to operate independently. The overall scheme was shown to be good agreement with all the in-pile data then available and implemented into the computer analysis of fuel element behavior. 48 refs., 1 fig.« less
Design of a reel mechanism for control of an orbiting single tether system

The preliminary design of a reel mechanism for the control of the GetAway Tether Experiment (GATE) is presented. The GATE is now part of the Tether Dynamics Explorer series (TDE) and consists of a small subsatellite tethered to a large body (Delta II second stage). A reel mechanism is housed in the subsatellite and used as the primary means of attitude control of the tether and subsatellite. Concepts used for the implementation of control software are discussed, and preliminary testing procedures are described. Results showing the capability of the prototype are presented and discussed. >
Severe and Refractory Peptic Ulcer Disease: The Diagnostic Dilemma Case Report and Comprehensive Review

The recognition of Helicobacter pylori infection as a cause of peptic ulcer disease, medical regimens to eradicate the organism, and the widespread use of proton pump inhibition to suppress gastric acid secretion have revolutionized the management of peptic ulcer disease. As a result, successful medical management of peptic ulcer disease has largely supplanted the need for gastric surgery by general surgeons. Surgery is reserved for complications of the disease, refractory disease, or rare causes of ulcer disease such as gastrinoma and Zollinger-Ellison syndrome. In this report, we describe a case of intractable peptic ulcer disease that progressed to gastric outlet obstruction despite maximal medical therapy. We review the diagnostic studies utilized to evaluate the potential etiologies of peptic ulcer disease and the difficulty in diagnosing gastrinoma and Zollinger-Ellison in the setting of potent medical acid suppression therapy.
Transient Hypertension Directly Impairs Endothelium-Dependent Vasodilation of the Human Microvasculature

Hypertension is associated with decreased endothelium-dependent vasodilation. However, whether endothelial dysfunction is a cause or a consequence of elevated blood pressure is unknown. Therefore, to determine whether hypertension can directly induce endothelial dysfunction, we investigated the effect of increases in intra-arterial pressure on endothelium-dependent vasodilation of the human microvasculature. Small arteries (internal diameter 202+/-75 micrometer) were isolated from gluteal fat biopsies in 12 healthy normotensive subjects (8 men and 4 women; age, 46+/-10 years). Arteries were cannulated and perfused in chambers oxygenated at 37 degrees C. Endothelium-dependent and -independent responses to acetylcholine (Ach; 10(-9) to 10(-4) mol/L) and sodium nitroprusside (SNP; 10(-9) to 10(-4) mol/L), respectively, were obtained after incubating the vessel with incremental intravascular pressures of 50, 80, and 120 mm Hg for 60 minutes each. The response to Ach was also obtained in different arteries after 3 consecutive incubation periods at 50 mm Hg. Arterial internal diameter was measured directly from amplified digital images. A significant reduction in the vasodilator response to Ach was observed with increases in intravascular pressure (mean vasodilation, 62%, 49%, and 26% at 50, 80, and 120 mm Hg, respectively; P<0.001). In contrast, the response to SNP showed a nonsignificant trend toward greater vasodilation with increases in pressure (mean vasodilation, 40%, 52%, and 57% at 50, 80, and 120 mm Hg, respectively; P=0.10). There was no difference in the consecutive dose-response curves to Ach obtained at the same intravascular pressure (mean vasodilation: 48%, 46%, and 49%; P=0.61). Transient increases in intravascular pressure significantly depress endothelium-dependent vasodilation in human resistance arteries. These findings suggest that elevated blood pressure per se may cause endothelial dysfunction in humans and have implications for the pathophysiology of endothelial dysfunction in hypertension.
Iterative procedures for reduction of blocking effects in transform image coding

The authors propose an iterative block reduction technique based on the theory of a projection onto convex sets. The idea is to impose a number of constraints on the coded image in such a way as to restore it to its original artifact-free form. One such constraint can be derived by exploiting the fact that the transform-coded image suffering from blocking effects contains high-frequency vertical and horizontal artifacts corresponding to vertical and horizontal discontinuities across boundaries of neighboring blocks. Another constraint has to be with the quantization intervals of the transform coefficients. Specifically, the decision levels associated with transform coefficient quantizers can be used as lower and upper bounds on transform coefficients, which in turn define boundaries of the convex set for projection. A few examples of the proposed approach are presented. >
Robot navigation by conditional sequencing

We investigate the application of conditional sequencing to robot navigation. Initial experimental results indicate that very robust navigation can be achieved by layering a conditional sequencer on top of a set of simple sensorimotor behaviors. The approach is uniquely flexible, permitting very complex tasks to be programmed reliably in very short periods of time. The technique was used in the recent American Association of Artificial Intelligence mobile robot contest. All of the contest-specific code was written in three days by a single programmer. The robot turned in the best overall performance of any entry. In addition, we present the results of over ninety formal experimental runs performed under a variety of circumstances. >
A circuit implementation for dynamic thermal management techniques

Dynamic thermal management (DTM) techniques like fetch-throttling, register rename throttling and register file occupancy throttling have some favorable features compared to dynamic voltage and frequency scaling (DVFS) technique for multi-core chip design. This paper presents the circuit implementations for the above mentioned non-DVFS techniques. A power-performance analysis of the implemented circuits has been performed to evaluate the performance of these DTM techniques, and to estimate the power overheads and the performance loss due to the inclusion of these DTM circuits. CPU bound workloads are used to simulate the proposed circuits.
Why the Negation Problem Is Not a Problem for Expressivism

The Negation Problem states that expressivism has insufficient structure to account for the various ways in which a moral sentence can be negated. We argue that the Negation Problem does not arise for expressivist accounts of all normative language but arises only for the specific examples on which expressivists usually focus. In support of this claim, we argue for the following three theses: 1) a problem that is structurally identical to the Negation Problem arises in non-normative cases, and this problem is solved once the hidden quantificational structure involved in such cases is uncovered; 2) the terms ‘required’, ‘permissible’, and ‘forbidden’ can also be analyzed in terms of hidden quantificational structure, and the Negation Problem disappears once this hidden structure is uncovered; 3) the Negation Problem does not arise for normative language that has no hidden quantificational structure. We conclude that the Negation Problem is not really a problem about expressivism at all but is rather a feature of the quantificational structure of the required, permitted, and forbidden
Apolipoprotein A-II: active or passive role in familial combined hyperlipidemia.

Familial combined hyperlipidemia (FCH) was originally identified as a new phenotype in studies of survivors of myocardial infarctions and their relatives.1–3 Patients with FCH were found to present with any of three patterns of lipoprotein distribution: elevated plasma levels of very low-density lipoprotein (VLDL) or low-density lipoprotein (LDL) or both. Within kindred, affected individuals often present with different lipoprotein patterns that tend to change over time; most patients manifest the combined pattern at some time.4 The phenotype also shares some features with dyslipidemic hypertension5 and the metabolic syndrome.6 Affected family members tend to display elevated serum apolipoprotein (apo) B levels7; in FCH, most studies report an approximate doubling of the secretion rate for apoB-100. The content of intermediate-density lipoproteins (IDL) is usually elevated as well. Of particular interest is the reduced high-density lipoprotein (HDL) cholesterol mass, due in part to the increased movement of cholesteryl esters from HDL particles to triglyceride-rich lipoproteins with increasing plasma triglycerides. This is mediated by cholesteryl ester transfer protein (CETP) and is consistent with a shift of HDL to smaller diameters. Allayee and colleagues report in this issue of Circulation Research the results of their study of apoA-II levels in families with FCH to determine whether the HDL-associated protein could play a role in the pathogenesis of this common complex lipid disorder.8 Their results suggest that plasma apoA-II variation is associated with certain traits that are altered in FCH, providing circumstantial evidence for a potential genetic component for this association. Whereas FCH patients present with either hypertriglyceridemia …
Generic consent for genetic screening.

Our ability to translate our expanding genetic knowledge into usable information for individual men and women is at best uncertain. Today many adults are offered genetic counseling to help them make reproductive decisions, either before they attempt to achieve a pregnancy or to help them decide whether to continue or terminate one. Taking a family history and, when indicated, recommending certain tests to identify carriers of genetic diseases are standard in obstetrical care. Today's screening tests usually focus on conditions that occur either in the family or in the racial or ethnic group of one or both prospective parents. As . . .
Rituals of introduction and revolving roles: Socialization in an online breast cancer community

Abstract This research sought to understand the role of information exchange and social support in an online breast cancer community relative to healthcare decisions and participants' everyday lives. Through a two-year ethnographic analysis comprising archives analysis, participant-observation, and 31 interviews, the data revealed that the forum's structure illustrated characteristics of a community of practice (CoP), a construct that has rarely been used in examining online health communities. Newcomers began as legitimate peripheral participants who progressed through the community from being novices, to novice/mentors, to mentor/experts. This progression represented a cycle of identification with three phases: a) an introductory phase, where novices made themselves known to the community and began to wrestle with breast cancer; b) learning the community's social practices and building identity as they evolved into novice/mentors who became more knowledgeable; and c) becoming mentor/experts who were looked up to and could provide information and support to others. Attaining mentor/expert status indicated a completion of the cycle in that mentor/experts were identified as being central to the community, and were also participating in the introduction phase by welcoming novices. Analyzing online health communities using a CoP perspective offers a lens that provides insights into the mechanisms that assist patients as they navigate through illness and treatment.
The Influence of Enhanced Side Impact Protection on Kinematics and Injury Measures of Far- or Center-Seated Children in Forward-Facing Child Restraints

Objective: To evaluate the influence of forward-facing child restraint systems’ (FFCRSs) side impact structure, such as side wings, on the head kinematics and response of a restrained, far- or center-seated 3-year-old anthropomorphic test device (ATD) in oblique sled tests.Methods: Sled tests were conducted utilizing an FFCRS with large side wings and with the side wings removed. The CRS were attached via LATCH on 2 different vehicle seat fixtures—a small SUV rear bench seat and minivan rear bucket seat—secured to the sled carriage at 20° from lateral. Four tests were conducted on each vehicle seat fixture, 2 for each FFCRS configuration. A Q3s dummy was positioned in FFCRS according to the CRS owner's manual and FMVSS 213 procedures. The tests were conducted using the proposed FMVSS 213 side impact pulse. Three-dimensional motion cameras collected head excursion data. Relevant data collected during testing included the ATD head excursions, head accelerations, LATCH belt loads, and neck loads.Results: Res...