cssi/SciSciGPT-SciSciNet huggingface dataset:
A Specification Framework for Real-Time Scheduling

Scheduling in Real-time systems differs from scheduling in conventional models in two principal ways: (a) Execution time variability, and (b) Existence of complex constraints between jobs. There is a third issue that indirectly depends upon the non-constant nature of execution times, viz. the degree of clairvoyance permitted by the application. Whereas traditional scheduling models assume fixed values for job execution time, we model execution times of jobs through convex sets; doing so permits the capturing of situations that could not be modeled otherwise. A feature that is unique to real-time systems is the presence of temporal relationships that constrain job execution. Consider for instance the requirement that job J1 should conclude 10 units before job J2. This can be modeled through a simple, linear relationship, between the start and execution times of jobs J1 and J2, however precedence graphs are inadequate for this purpose. In hard, real-time scheduling, it is important to guarantee a priori, the schedulability of the system, since the violation of a constraint leads to catastrophic consequences. Depending upon the nature of the application involved, there are 3 different schedulability specifications viz. Static (Zero-Clairvoyant), Parametric (Partially Clairvoyant) and Co-Static (Totally Clairvoyant). Each specification affords a different level of flexibility and has different dispatching concerns. In this paper, we present a framework that enables the specification of real-time scheduling problems and discuss the relationship between flexibility and complexity in the proposed model. We motivate each aspect of our model through examples from real-world design.
Spread spectrum sequence estimation and bit synchronization using an EM-type algorithm

The maximum likelihood (ML) estimation method for simultaneous amplitude, time delay, and data demodulation in direct sequence spread spectrum communication is proposed. The likelihood function is analytically intractable, so we consider a recursive estimation algorithm. The expectation-maximization (EM) algorithm has found increasing use in similar problems, however, for this case it is analytically intractable. A variant of the EM algorithm, called space alternating generalized EM (SAGE), has been derived. We apply the SAGE algorithm to the sequence estimation problem in a way which allows for simple sequential updates of the parameters. The resulting algorithm maximizes the penalized likelihood function, where the penalty is chosen to ensure good synchronization performance. Simulation results show that the algorithm has fast convergence, and essentially achieves optimal performance.
Ganciclovir Treatment of Murine Cytomegalovirus Infection in Mice Immunosuppressed by Prior Infection with Friend Leukaemia Virus

Since many of the severe cytomegalovirus infections in humans occur in individuals immunosuppressed by the human immunodeficiency virus, we developed an analogous murine model for studying this disease. BALB/c mice infected with the Friend retrovirus complex (FV) were immunosuppressed (i.e., exhibited reduced spleen-cell mitogenic responses and natural killer cell activity) by 21 days after FV inoculation. Challenge with murine cytomegalovirus (MCMV) at that time led to mortality at doses generally non-lethal to normal mice. Superinfection of FV-infected mice with MCMV reduced spleen cell FV infectious centres and splenomegaly, and extended the lives of mice surviving the MCMV infection. Once-daily ganciclovir treatments of 12.5,25, and 50 mg kg−1 given to dually-infected mice for 5 days starting 24 h after MCMV inoculation resulted in 90–100% survival at 14 days (relative to MCMV inoculation) compared to 15% survival in the placebo group. By 70 days, survival in the drug-treated and placebo groups were 0...
Detectability analysis of detection and estimation of structured action from cluttered data

There is good reason to model an asymmetric threat (a structured action such as a terrorist attack) as an HMM. Thence there is a means (described in earlier work) to detect it via the novel Bernoulli filter paradigm that is emerging as an integrated tracker/track-management tool. This paper details additional progress made to model the detectability of a hidden Markov model (HMM) that is observed in the presence of false measurements or clutter. The ultimate goal of this analysis is to be able to make statements regarding the minimum complexity that an HMM would need to involve in order that it be detectable with reasonable fidelity, as well as upper bounds on the level of clutter (expected number of false measurements) and probability of miss of a relevant observation. Put simply, if a threat modeled as an HMM has (say) three components — transaction O1, followed by O2 and then O3 with modeled delays in between — then this would only be detectable if the delays were very small or if there were very little clutter. A more feasible situation would involve 20 or 30 transactions. To characterize this more fully is the goal of this manuscript.
Telecommunications: The Las, and the Next, 50 Years

Publisher Summary This chapter discusses the past and next 50 years of telecommunications. The present-day world telecommunication network is the most complex, extensive, and costly of mankind's technological creations. In the early 1940s, telecommunication services in the United Kingdom were predominantly for telephone speech and telegrams, with limited low-speed data and facsimile transmission. Telegrams were transmitted using teleprinters operated at 50 bits/s, corresponding to the speed of the average typist. Video transmission hardly existed except for a few miles on cable pairs in London. The war years, 1939–1945, gave a strong impetus to the development of radio and electronic technology for military purposes that later proved of value for civil telecommunications. By 1986, there were more than 65,000 km of 140 Mbit/s optical fiber systems in operation in the British Telecom intercity network, and 565 Mbit/s systems were beginning to come into service. Progress has been made to reduce the time and improve the quality of facsimile transmission; the six minutes required to transmit an A4 page in the 1960s was reduced to 3 minutes by 1976. Many laboratories are now exploring optical switching with a view to closer integration with optical transmission and ultimately faster, more flexible, and lower cost telecommunication systems. The continuing development of information technology and new services—such as the video library—will require data bases of even larger capacity and fast access, while the effective implementation of the virtual reality concept requires data bases larger by several orders of magnitude than have been achieved so far.
Locking And Recovery In A Shared Database System: An Application Programming Tutorial

A comprehensive tutorial is presented on the subject of locking and recovery. The viewpoint taken is that of the application programmer (primarily). The material covered represents a synthesis of ideas from many sources in particular, the language UDL is used as an illustration of how locking and recovery features can be surfaced in an application programming language.
Hepatocellular Hyalin in Cholestasis and Cirrhosis: Its Diagnostic Significance

Liver tissue of patients with various stages of alcoholic liver injury, with cholestatic liver diseases and with various types of cirrhosis, were examined for the presence of hyalin, mainly by light microscopy and, in selected instances, also by electron microscopy. Hyalin was detected in alcoholic liver disease and in prolonged cholestasis, mainly in primary biliary cirrhosis. It was not found in diseases in which cholestasis was of shorter duration and was predominantly central in location. Electron microscopically, hyalin was identical in alcoholic hepatitis and in primary biliary cirrhosis, although the pattern of injury of hepatocytic organelles was different in these diseases. A morphologic relation between hyalin and cholestasis or any other hepatocellular abnormalities could not be detected. Hyalin was also found in advanced nonalcoholic cirrhosis, in Wilson's disease, and in Indian childhood cirrhosis, and with the exception of the last, it was always associated with peripheral cholestasis. Centrolobular hyalin in specimens with intact lobular architecture is diagnostic for alcoholic liver injury. Peripheral hyalin in the absence of cirrhosis favors primary biliary cirrhosis over extrahepatic biliary obstruction. Hyalin throughout nodules in advanced cirrhosis does not necessarily indicate alcoholic liver disease, Wilson's disease, or Indian childhood cirrhosis, but also occurs in "cryptogenic" cirrhosis.
Comparison of Modern and Historical Fish Catches (AD 750–1400) to Inform Goals for Marine Protected Areas and Sustainable Fisheries

We tested the unsustainable fishing hypothesis that species in assemblages of fish differ in relative abundance as a function of their size, growth rates, vagility, trophic level, and diet by comparing species composition in historical bone middens, modern fisheries, and areas closed to fishing. Historical data came from one of the earliest and most enduring Swahili coastal settlements (approximately AD 750-1400). Modern data came from fisheries near the archeological site and intensively harvested fishing grounds in southern Kenya. The areas we sampled that were closed to fishing (closures) were small (<28 km(2) ) and permanent. The midden data indicated changes in the fish assemblage that are consistent with a weak expansion of fishing intensity and the unsustainable fishing hypothesis. Fishes represented in the early midden assemblages from AD 750 to 950 had longer life spans, older age at maturity, and longer generation times than fish assemblages after AD 950, when the abundance of species with longer maximum body lengths increased. Changes in fish life histories during the historical period were, however, one-third smaller than differences between the historical and modern assemblages. Fishes in the modern assemblage had smaller mean body sizes, higher growth and mortality rates, a higher proportion of microinvertivores, omnivores, and herbivores, and higher rates of food consumption, whereas the historical assemblage had a greater proportion of piscivores and macroinvertivores. Differences in fish life histories between modern closures and modern fishing grounds were also small, but the life histories of fishes in modern closures were more similar to those in the midden before AD 950 because they had longer life spans, older age at maturity, and a higher proportion of piscivores and macroinvertivores than the modern fisheries. Modern closures and historical fish assemblages were considerably different, although both contained species with longer life spans.
Regulation of Leptin Production in Humans

Serum levels of the adipocyte hormone leptin are increased in proportion to body fat stores as a result of increased production in enlarged fat cells from obese subjects. In vitro studies indicate that insulin and glucocorticoids work directly on adipose tissue to upregulate in a synergistic manner leptin mRNA levels and rates of leptin secretion in human adipose tissue over the long term. Thus, the increased leptin expression observed in obesity could result from the chronic hyperinsulinemia and increased cortisol turnover. Superimposed upon the long-term regulation, nutritional status can influence serum leptin over the short term, independent of adiposity. Fasting leads to a gradual decline in serum leptin that is probably attributable to the decline in insulin and the ability of catecholamines to decrease leptin expression, as observed in both in vivo and in vitro studies. In addition, increases in serum leptin occur approximately 4-7 h after meals. Increasing evidence indicates that insulin, in concert with permissive effects of cortisol, can increase serum leptin over this time frame and likely contributes to meal-induced increases in serum leptin. Further research is required to elucidate the cellular and molecular mechanisms underlying short- and long-term nutritional and hormonal regulation of leptin production and secretion.
Bulk attenuation in the earth's mantle due to phase transitions

Abstract The calculated bulk attenuation due to phase transition from mineral physics data is reported here. With relaxation time less than 1 s, the calculated value for a pyrolite mantle is consistent with the inverted bulk attenuation of the upper mantle from seismic observations. The two important mechanisms of phase transitions, diffusion-controlled and kinetics-controlled, have different relaxation time as indicated by the models here. The diffusion controlled is more likely to contribute to the observed seismic bulk attenuation than the kinetic-controlled process based on the available diffusivity and kinetics data. The correlation between the bulk attenuation and relaxation time emphasizes the importance of a number of parameters in the mineral physics database such as Fe–Mg diffusivity and kinetics in olivine–wadsleyite–ringwoodite–perovskite, Mg–Ca–Al–Si diffusivity and kinetics in pyroxene–garnet–Ca perovskite, some of which are still unknown.
Lack of protection by ascorbic acid from lethality resulting from exposure to 1 atm O2

The role of ascorbic acid in protecting animals against the toxic effects of exposure to 1 atm. of O2 was examined. The mean time until death resulting from exposure to one atm. O2 was not different in rats treated intraperitoneally 3 times per day with 1.5 g/kg ascorbic acid compared to saline injected controls. Exposure of rats to one atm. O2 for 48 hr did not alter ascorbic acid or non-protein thiol concentration in lung or liver compared to room air controls. Lung ascorbic acid concentration was markedly depressed in guinea pigs fed an ascorbic acid-deficient diet for 6 days prior to O2 exposure. However, the mean time until death of ascorbic acid-deficient guinea pigs did not significantly differ from those fed an ascorbic acid-supplemented diet. Exposure to one atm. O2 of guinea pigs fed an ascorbic acid-deficient diet or an ascorbic acid-supplemented diet failed to decrease the concentration of ascorbic acid or of non-protein thiol in lung. Results from this study do not support an involvement of ascorbic acid in protection from pulmonary oxygen toxicity.
Psychosocial Predictors of Binge Eating and Purging Behaviors among Adolescents with and without Diabetes Mellitus

Purpose: This study aims to compare dieting, binge eating, and purging behaviors, and to examine predictors of binge eating and purging behaviors among adolescents with and without Diabetes Mellitus (DM). Methods: The index group included 310 adolescents who reported that they had DM on a statewide population survey of 36,284 adolescents in grades 7–12 in Minnesota. The comparison group included a random sample matched for socioeconomic status (SES), of 850 adolescents without chronic illness. Disordered eating behaviors assessed in the present study included binge eating, vomiting, laxative use, and diuretic use. Potential predictor variables assessed included weight loss behaviors, body image, sexual abuse, sexual attractions, emotional well-being, family connectedness, poor school performance, age, race, Body Mass Index (BMI), and SES. Results: Binge eating and purging were significantly more prevalent among adolescents with DM than among the comparison group. Different risk profiles were found for adolescents with and without DM and for males and females. Predictors of binge eating and purging among females with DM included weight dissatisfaction, bisexual/homosexual attractions, and younger age. Predictors among males with DM included bisexual/homosexual attractions, younger age, sexual abuse, and an interaction between sexual abuse and emotional well-being. Conclusions: Adolescents with DM should be screened for unhealthy weight control practices and eating disorders. If disordered eating is present, clinicians need to be sensitive to the variety of factors possibly associated with these behaviors among different individuals.
Increased efficiency for large-volume gas chromatographic samples

Summary The authors studied the effect of adding a packed, enlarged-diameter section to a gas chromatographic column. Two columns, identical in all respects except for one having an enlarged section, exhibit markedly different efficiencies. The use of the enlarged section increases the efficiency and also increases the maximum volume of sample which may be handled by the packed column.
Social Theory as a Cognitive Neuroscience

In the nineteenth century, there was substantial and sophisticated interest in neuroscience on the part of social theorists, including Comte and Spencer, and later Simon Patten and Charles Ellwood. This body of thinking faced a dead end: it could do little more than identify highly general mechanisms, and could not provide accounts of such questions as `why was there no proletarian revolution?' Psychologically dubious explanations, relying on neo-Kantian views of the mind, replaced them. With the rise of neuroscience, however, some of the problems of concern to earlier thinkers, such as imitation, have revived because of the discovery of neuronal mechanisms, or through fMRI studies. The article reviews the history and discusses the implications of current work for the reconsideration of traditional social theory concepts. It is suggested that certain kinds of bridging work with neuroscience would enable us to answer many questions in social theory that empirical sociology has failed to answer.
Geoarchaeology and late glacial landscapes in the western lake superior region, Central North America

The transition from full glacial to interglacial conditions along the southern margin of the Laurentide ice sheet resulted in dramatic changes in landscapes and biotic habitats. Strata and landforms resulting from the Wisconsin Episode of glaciation in the area directly west of Lake Superior indicate a context for late Pleistocene biota (including human populations) connected to ice margins, proglacial lakes, and postglacial drainage systems. Late Glacial landscape features that have the potential for revealing the presence of Paleoindian artifacts include abandoned shorelines of proglacial lakes in the Superior and Agassiz basins and interior drainages on deglaciated terrains. The linkage between Late Pleistocene human populations and Rancholabrean fauna has yet to be demonstrated in the western Lake Superior region, although isolated remains of mammoth ( Mammuthus) have been documented, as well as fluted points assigned to Clovis, Folsom, and Holcombe-like artifact forms. Agate Basin and Hell Gap (Plano-type) artifacts also imply the presence of human groups in Late Glacial landscapes associated with the Agassiz and Superior basins. © 2007 Wiley Periodicals, Inc.
Training programmes for the systems approach to nuclear security

In support of the US Government and the International Atomic Energy Agency (IAEA) Nuclear Security Programmes, Sandia National Laboratories (SNL) has advocated and practised a risk-based, systematic approach to nuclear security. The risk equation has been implemented as the basis for a performance methodology for the design and evaluation of Physical Protection Systems against a Design Basis Threat (DBT) for theft or sabotage of nuclear and/or radiological materials. Since integrated systems must include people as well as technology and the man?machine interface, a critical aspect of the human element is to train all stakeholders in nuclear security on the systems approach. Current training courses have been beneficial but are still limited in scope. SNL has developed two primary international courses and is completing development of three new courses that will be offered and presented in the near term. In the long-term, SNL envisions establishing a comprehensive nuclear security training curriculum that will be developed along with a series of forthcoming IAEA Nuclear Security Series guidance documents.
Strategies, management values, and outcomes in manufacturing companies

Popular literature on corporate cultures presents stories about the importance of management's values. This article reports statistical analyses based on data obtained from middle and top managers employed by manufacturing companies. Results show that companies pursuing a strategy of cost leadership possess cultures emphasizing pragmatic values and strong performance norms. Moreover, these values and norms relate significantly with managers' career satisfaction and their organizational commitment.
A Matlab-Based Toolkit to Program Microcontrollers for Use in Teaching Mechanisms and Robotics

Programming is an essential skill for engineering students, particularly in areas of mechanisms and robotics, mechatronics and design. Students receive formal programming training early on in the typical engineering curriculum, but generally demonstrate difficulty in implementing programming skills to solve engineering problems in later courses. This is due to a number of factors including a lack of cohesion in programming practice in the curriculum and improper context for introducing programming to engineering students. The authors have developed a hands-on programming toolkit to allow engineers to learn programming on a Microcontroller and associated hardware (sensors, motors, output devices) using the Matlab environment. This toolkit is applicable to all levels of students, from freshman in their introductory programming course through senior and graduate students. In this hands-on toolkit, the MCU becomes the target for the program. Once programmed, the hardware runs independently and can readily be implemented outside of class or the lab. The primary method of programming an MCU is with C or assembly. One of the unique offerings of this toolkit is that it provides a way to program an MCU directly using Matlab. The premise is that adding an MCU as a programming target, rather than simply a PC, may provide a more appropriate context for engineers to learn programming. In addition, the MCU target will offer a greater number of options for incorporating programming into the engineering curriculum. This paper will present an overview of the programming toolkit and environment. The paper will also present a series of programming exercises related to dynamics of machinery, robotics, mechatronics and controls.Copyright © 2014 by ASME
Anal skin tags in inflammatory bowel disease: New observations and a clinical review

Background: The association between intestinal Crohn's disease (CD) and specific perianal abnormalities called anal skin tags (AST) has been recognized but not well defined. Skin tags have been classified into 2 types: 1) raised, broad, or narrow, single or multiple, soft or firm, and painless, often referred to as “elephant ears”; or 2) edematous, hard, often cyanotic, tender or not, and typically arising from a healed anal fissure, ulcer, or hemorrhoid. The aims of this study were to i) better characterize those skin tags identified by the term “elephant ears” and differentiate them from other types of AST; ii) compare their prevalence in patients with CD and ulcerative colitis (UC); iii) observe the relationship of the skin tags to the location of the primary bowel disease; and iv) to discuss the value of these typical AST in making an early diagnosis of CD. Methods: Photographs of all AST were taken when present at lower endoscopy in 170 consecutive patients with inflammatory bowel disease (IBD) seen in the private office of the senior investigator and Lenox Hill Hospital. Data was gathered with respect to major differences between the 2 types of AST. The location of the primary bowel disease for these patients was obtained from an extensive IBD computer database and review of details from charts. Results: Specific features of AST were described and served to favor type 1 versus type 2. AST were found more frequently in patients with CD (75.4%) as compared to patients with UC (24.6%), confirming previous observations that they are more diagnostic of CD (P = 0.005). Subset analysis revealed a trend with a greater incidence of AST in patients with colitis (46.9%) as compared to patients with ileitis (36.7%) and ileocolitis (16.3%) (P = 0.067). Conclusions: We provide photographs with the most characteristic features of AST and attempt to separate elephant ears (type 1) from less typical AST (type 2) in CD. Our study confirms previous reports that AST are more commonly found in association with CD as compared with UC and more so in the presence of disease limited to the colon as compared to disease elsewhere in the bowel. Our observations support the diagnostic significance of AST heralding the diagnosis of CD when they are discovered on physical exam, especially in young people with diarrhea, abdominal pain, and/or growth retardation. (Inflamm Bowel Dis 2008)
Microstructural studies of friction stir welds in 2024-T3 aluminum

Friction stir welds in 7 mm thick, 2024-T351 aluminum rolled sheet material have been completed. Metallurgical, hardness and quantitative energy dispersive X-ray measurements have been performed which demonstrate that a segregated, banded, microstructure consisting of alternating hard particle rich and hard particle poor regions is developed. Mixed-mode I/II monotonic fracture experiments confirm that the observed banded microstructure affects the macroscopic fracture process. Since the band spacing is directly correlated with the welding tool advance per revolution, our results indicated that the opportunity exists to manipulate the friction stir weld process parameters in order to modify the weld microstructure and improve a range of material properties, including fracture resistance.
Telomeres, lifestyle, cancer, and aging

Purpose of reviewThere has been growing evidence that lifestyle factors may affect the health and lifespan of an individual by affecting telomere length. The purpose of this review was to highlight the importance of telomeres in human health and aging and to summarize possible lifestyle factors that
The role of Bcl-XS in radiation sensitivity

Abstract Morgan, M. A., Poynter, J. N., Maybaum, J. and Lawrence, T. S. The Role of Bcl-XS in Radiation Sensitivity. Radiat. Res. 161, 535–539 (2004). Bcl-XS is a pro-apoptosis member of the Bcl2 family that has been shown to induce cell death and enhance chemosensitivity. We have investigated the effect of Bcl-XS overexpression on radiation sensitivity. Using a tetracycline-repressible system, we found that removal of tetracycline for 16 h induced Bcl-XS and reduced the surviving fraction of NIH 3T3 cells to 25%. However, radiation sensitivity was not significantly affected by Bcl-XS expression; the mean inactivation doses for Bcl-XS repressed and Bcl-XS induced cells were 2.7 ± 0.3 and 2.3 ± 0.1 Gy, respectively. We conclude that Bcl-XS induces cell death without affecting radiation sensitivity. These results suggest that mitochondrial pathways to apoptosis may not have a significant role in survival after irradiation.
The activation of spatial antecedents from overt pronouns in american sign language

Abstract Two experiments are presented which investigate the processing of pronominal reference in American Sign Language (ASL). Pronominal reference in ASL involves the association of nominals with loci in signing space, and pronouns are directed towards these spatial loci. Deaf subjects viewed videotaped ASL sentences with and without pronouns and responded to probe signs presented either immediately after the pronoun or after a 1000-msec delay. In both experiments, we found evidence for referent activation by an overt pronoun: responses to referent probes were faster when a pronoun was present in the sentence. Experiment 1 indicated that pronoun activation was not immediate, and there was no strong evidence for the inhibition of non-referents. Experiment 2 was designed to investigate whether the pronoun also activated a representation of the spatial locus associated with the referent. If the pronoun activates a spatial representation, we predicted that spatially incongruent probes would produce a great...
Identification and functional analysis of NOL7 nuclear and nucleolar localization signals

NOL7 is a candidate tumor suppressor that localizes to a chromosomal region 6p23. This locus is frequently lost in a number of malignancies, and consistent loss of NOL7 through loss of heterozygosity and decreased mRNA and protein expression has been observed in tumors and cell lines. Reintroduction of NOL7 into cells resulted in significant suppression of in vivo tumor growth and modulation of the angiogenic phenotype. Further, NOL7 was observed to localize to the nucleus and nucleolus of cells. However, the mechanisms regulating its subcellular localization have not been elucidated. An in vitro import assay demonstrated that NOL7 requires cytosolic machinery for active nuclear transport. Using sequence homology and prediction algorithms, four putative nuclear localization signals (NLSs) were identified. NOL7 deletion constructs and cytoplasmic pyruvate kinase (PK) fusion proteins confirmed the functionality of three of these NLSs. Site-directed mutagenesis of PK fusions and full-length NOL7 defined the minimal functional regions within each NLS. Further characterization revealed that NLS2 and NLS3 were critical for both the rate and efficiency of nuclear targeting. In addition, four basic clusters within NLS2 and NLS3 were independently capable of nucleolar targeting. The nucleolar occupancy of NOL7 revealed a complex balance of rapid nucleoplasmic shuttling but low nucleolar mobility, suggesting NOL7 may play functional roles in both compartments. In support, targeting to the nucleolar compartment was dependent on the presence of RNA, as depletion of total RNA or rRNA resulted in a nucleoplasmic shift of NOL7. These results identify the minimal sequences required for the active targeting of NOL7 to the nucleus and nucleolus. Further, this work characterizes the relative contribution of each sequence to NOL7 nuclear and nucleolar dynamics, the subnuclear constituents that participate in this targeting, and suggests a functional role for NOL7 in both compartments. Taken together, these results identify the requisite protein domains for NOL7 localization, the kinetics that drive this targeting, and suggest NOL7 may function in both the nucleus and nucleolus.
PVCs arising from the moderator band: An under-recognized trigger for idiopathic VF?

Idiopathic ventricular fibrillation (VF) occurs in the absence of underlying structural heart disease or ECG abnormalities and accounts for a minority of patients who survive out-of-hospital cardiac arrest. Although implantable cardioverter-defibrillator therapy typically is recommended for patients who have been resuscitated from cardiac arrest, arrhythmias may recur and even can lead to electrical storms. Recent advances in the understanding of the mechanisms and triggers responsible for VF have resulted in the use of catheter ablation strategies aimed at ablation of monomorphic focal premature ventricular contractions (PVCs) responsible for triggering ventricular arrhythmias. In many cases, these triggers of VF may be related to potentials arising from His–Purkinje fibers. 1-6 In patients without structural heart disease, idiopathic VF/polymorphic ventricular tachycardia (VT) also may arise from triggers located in the right ventricular outflow tract, 1,6 anterior wall of the right ventricle, 1,7 papillary muscles, 5 left ventricular outflow tract, 5 or right ventricular moderator band (MB). 8 However, ablation of arrhythmias in some regions, including the papillary muscles or MB, may be challenging because of issues of catheter contact or stability, thus limiting effective energy delivery. In addition, these potential sources of triggers may be under-recognized without a tool that allows direct visualization of endocardial structures during the ablation procedure. In this issue of HeartRhythm, Sadek et al 8 report an MB source of PVCs in 10 patients presenting with monomorphic VT or idiopathic VF and eloquently describe ECG and procedural findings in these patients undergoing catheter ablation. Although the initial success rates for VF ablation aimed at targeting the critically timed PVCs responsible for triggering VF have been reported to be 81% to 100%, similar to the immediate success rate of 100% in the present study, short-term recurrence rates were up to 11% to 18%, 1,2,6 which are higher than recurrence rates typically seen with other forms of idiopathic ventricular arrhythmias. In the current study, 60% of patients with an MB source of PVCs required a second ablation procedure days to months after the initial procedure. 8 Radiofrequency (RF) ablation of PVCs localized to endocardial structures may be particularly challenging. In addition, these potential sources of triggers for VT/VF may be under-recognized.
Rethinking online discourse: Improving learning through discussions in the online classroom

As colleges continue to expand online offerings, student participation within courses should be assessed to ensure that teachers can best implement effective, responsible lesson plans. This study examined discourse in an online classroom in order to gauge student participation by observing student-to-student and student-to-instructor exchanges within the discussion board. Classroom discourse was analyzed using Stahl's computer supported collaborative learning methodology. Data was collected to assess development of classroom dialogue through group collaboration, and to determine whether participants were interpreting previous posts and contributing to the development of the discussion topic. This study shows that students within the online classroom were able to construct deeper meanings in classroom dialogues through thoughtful and personal contributions, thereby reaching new understandings through collaborative discussion. This study contends that through insightful planning and guided responses, instructors can manage online classroom discussions to better direct student communications in order to improve collaborative learning and knowledge construction.
Rapid spatially scanning ir heterodyne interferometer.

An interferometer has been developed which provides repetitive spatial profiles of phase objects in the ir using a single detector channel. By combining Bragg cell heterodyne interferometry with a high speed (0.5 million rpm) turbine driven rotating mirror scanner, the system effectively converts temporal fringes to spatial fringes. Designed for applications in plasma diagnostics, the system scans a 5-cm field with a 2-mm resolution in 200 nsec. Operating in a double pass mode at 3.4 μm, the phase accuracy is better than 0.1 fringe. The concept is applicable over a wide range in wavelength, scan format, and resolution.
Association of newer diastolic function parameters with age in healthy subjects: a population-based study.

Abstract Objectives We sought to determine if newer Doppler diastolic function parameters are associated with age and to define age-stratified reference ranges for these parameters in a population-based setting. Background Although newer Doppler parameters aid in the evaluation of diastolic function and filling pressures, age-specific reference ranges are poorly described. Methods Randomly selected residents of Olmsted County, Minn, age ≥ 45 years were studied (n = 2042) prospectively. Those without a history of cardiovascular disease or abnormal 2-dimensional echocardiograms were selected. Measured parameters included the transmitral early (E) and late (A) filling velocities at rest and with Valsalva, A duration, pulmonary venous atrial reversal duration, lateral and septal early diastolic mitral annular velocities, E/lateral early diastolic mitral annular velocity, E/septal early diastolic mitral annular velocity, and the index of left ventricular myocardial performance. Results A total of 1012 subjects met the inclusion criteria. Both A duration ( r = 0.18, P r = 0.28, P r = 0.07, P = .036). The E/A ratio at peak Valsalva correlated with age ( r = −0.54, P r = 0.08, P = .032). Both E/lateral early diastolic mitral annular velocity ( r = 0.39, P r = 0.27, P r = 0.08, P = .014). Age specific reference ranges (median, 5th and 95th percentiles) for all parameters are provided. Conclusions All newer Doppler diastolic function parameters showed a variable but significant correlation with age. Age-specific reference values will aid in the interpretation of diastolic function parameters.
Necessary and sufficient conditions for bipolar incoherent spatial filtering

Necessary and sufficient conditions for the realization of a bipolar point-spread function in an incoherent spatial-filtering system are proved. It is shown that the bipolar function must be real, bipolar, absolutely integrable, and band limited.
A MESFET Model for Use in the Design of GaAs Integrated Circuits

A MESFET model is presented that is suitable for use in conventional, time-domain circuit simulation programs. The parameters of the model are evaluated either from experimental data or from more detailed device analysis. The model is shown to be more complete than earlier models, which neglect transit-time and other effects. An integrated circuit (IC) design example is discussed.
Developmental changes in mullerian inhibiting substance in the cynomolgus monkey, Macaca fascicularis

Mullerian inhibiting substance (MIS) is a glycoprotein hormone produced in Sertoli cells of the fetal and postnatal testis, and granulosa cells of the pubertal ovary. We examined MIS expression in a nonhuman primate, the cynomolgus macaque monkey (Macaca fascicularis), to define an animal model for studying MIS gene regulation. Changes in testicular MIS mRNA with age were assessed by in situ hybridization of prepubertal to adult testes, Northern analysis of pubertal and adult specimens, and determination of serum MIS concentrations from infancy to adulthood. We found that MIS expression was highest in the youngest animals and decreased progressively with increasing age. Serum MIS concentrations correlated inversely with increasing age (r = -0.74), body weight (r = -0.79), and testicular volume (r = -0.73), but not with testosterone levels (r = -0.35). The mean MIS concentrations +/- SEM for the four developmental age groups were 270.6 +/- 23.8 (infants), 195.5 +/- 18.5 (juveniles), 102.7 +/- 28.4 (peripubertals), and 51.6 +/- 7.1 (adults). This study confirms that nonhuman primate and human MIS are highly homologous and have similar developmental patterns. The normative data for serum MIS concentrations in cynomolgus monkeys at different ages and developmental stages will be invaluable for further work examining MIS regulation.
Optic pit maculopathy after laser-assisted in situ keratomileusis.

Abstract Case report: Optic disc pit is an embryological malformation of the optic nerve that occurs in less than one in 10000 people. It is 10%–15% bilateral, and 25% to 70% of patients develop a neurosensory macular detachment within the 2nd to 4th decade. Comments: We report a case of unilateral optic disc pit maculopathy 2 months after laser-assisted in situ keratomileusis (LASIK) revision.
Systems-based modeling of generation variability under alternate geographic configurations of photovoltaic (PV) installations in Virginia

Abstract With increased focus on renewable energy in our modern era, it is increasingly important to understand the impact of policies on the performance and reliability of regional energy systems. This research develops a model to understand how geographic dispersion of PV installations impacts the reliability of electricity generated from the total PV network, measured by the variance of the distribution of generated electricity. Using NREL data, beta probability distributions of sunlight (kWh/m2/day) in various regions of Virginia are estimated using a fitting method that minimizes the Kolmogorov–Smirnov test statistic. A Monte Carlo simulation model is developed to measure PV electricity generation from multiple centralized and dispersed configurations over 100,000 days of probabilistic sunlight. There is a calculable tradeoff between average generation and generation variability, and increased geographic dispersion of PV installations can decrease this variability. Controlling variable generation through policies that promote efficient PV siting can help provide reliable power, minimizing the need for load-balancing peaking power infrastructure and costly electricity purchases from the grid. Using a tradeoff framework of generation and costs, this paper shows that geographically dispersed generation can mitigate the risk of unreliable solar generation that can significantly impact the end-user costs and make PV infrastructure unattractive.
Synthesis and characterization of main‐chain polyaminimides

Three novel main-chain polyarninimides were prepared containing rigid and/or flexible groups within the backbone. The polymer precursors were initially synthesized from bis-dimethylhydrazides and dihalides at room temperature through the Menschulkin reaction, which yielded hydrazinium ionenes. In a similar fashion, low molecular weight model compounds were also prepared in order to confirm the structures of the ionene polymers. It was found that the ionenes were totally, or at least partially, converted o the aminimide form in the presence of water alone, while the model cationic compounds required a strong base before conversion to their corresponding aminimides. These new polymers were characterized by (heir infrared and NMK spectra, as well as dilute solution viscosity. Preliminary solution properties indicate that the hydrazinium form of the polymers behave as poly electrolytes, whereas the aminimide form behaves as a neutral polymer.
Greater amount of visual feedback decreases force variability by reducing force oscillations from 0–1 and 3–7 Hz

The purpose was to determine the relation between visual feedback gain and variability in force and whether visual gain-induced changes in force variability were associated with frequency-specific force oscillations and changes in the neural activation of the agonist muscle. Fourteen young adults (19–29 years) were instructed to accurately match the target force at 2 and 10% of their maximal voluntary contraction with abduction of the index finger. Force was maintained at specific visual feedback gain levels that varied across trials. Each trial lasted 20 s and the amount of visual feedback was varied by changing the visual gain from 0.5 to 1,474 pixels/N (13 levels; equals ~0.001–4.57°). Force variability was quantified as the standard deviation of the detrended force data. The neural activation of the first dorsal interosseus (FDI) was measured with surface electromyography. The mean force did not vary significantly with the amount of visual feedback. In contrast, force variability decreased from low gains compared to moderate gains (0.5–4 pixels/N: 0.09 ± 0.04 vs. 64–1,424 pixels/N: 0.06 ± 0.02 N). The decrease in variability was predicted by a decrease in the power of force oscillations from 0–1 Hz (~50%) and 3–7 Hz (~20%). The activity of the FDI muscle did not vary across the visual feedback gains. These findings demonstrate that in young adults force variability can be decreased with increased visual feedback gain (>64 pixels/N vs. 0.5–4 pixels/N) due to a decrease in the power of oscillations in the force from 0–1 and 3–7 Hz.
Long-range cooperative interactions modulate dimerization in SARS 3CLpro.

Severe acute respiratory syndrome (SARS) is an infectious disease caused by the human coronavirus, SARS-CoV. The main viral protease, SARS 3CLpro, is a validated target for the development of antiviral therapies. Since the enzyme is a homodimer and the individual monomers are inactive, two approaches are being used to develop inhibitors: enzyme activity inhibitors that target the active site and dimerization inhibitors. Dimerization inhibitors are usually targeted to the dimerization interface and need to compete with the attractive forces between subunits to be effective. In this paper, we show that the dimerization of SARS 3CLpro is also under allosteric control and that additional and energetically more favorable target sites away from the dimerization interface may also lead to subunit dissociation. We previously identified a cluster of conserved serine residues (Ser139, Ser144, and Ser147) located adjacent to the active site of 3CLpro that could effectively be targeted to inactivate the protease [Ba...
High-density, end-to-end optoelectronic integration and packaging for digital-optical interconnect systems

Recent progress toward implementing high-density, optical-digital building blocks necessary to accomplish efficient, end-to-end optical interconnect architecture on low cost FR-4 boards has been demonstrated. The optical interconnect system consists of fabricating an optical buffer layer separating board metallurgy from the optical lightwave circuit layer, and implementing optical links between embedded lasers and detectors. We will show an example of 1310 nm light from an edge emitting distributed-feedback or Fabry-Perot laser operating at 10 Gb/s being guided to the photodetector by a polymer waveguide. Both lasers and detector are embedded in the waveguide and all construction is built on a low-cost FR-4 board with 3 levels of metallurgy.
Spinal cord atrophy in multiple sclerosis and relationship with disability across clinical phenotypes

Abstract Background Several studies have shown a relationship between spinal cord atrophy and clinical disability in patients with multiple sclerosis (MS). Objectives We examined the correlation between cervical cord cross-sectional area at the C2 vertebral level (CSA-C2) and the expanded disability status scale (EDSS) in patients with relapsing-remitting and progressive forms of MS. The latter included both secondary and primary progressive MS patients. Methods A total of 150 patients with MS were recruited from the Wayne State University MS clinic. Ninety-three had relapsing-remitting MS and 57 patients had progressive MS. MRI scan of the cervical cord was obtained for each patient. Correlation studies and multivariate regression analysis was performed, blinded to clinical status. Results The mean age was 41.3 year old, 64.6% were women, mean disease duration was 11.2 years, CSA-C2 was 80.2mm 2 and mean EDSS was 3.8. There was significant correlation between CSA-C2 and EDSS ( r −0.75, p 2 and 87.3mm 2 in the progressive and relapsing-remitting groups, respectively ( p Conclusions Our study demonstrates that CSA-C2 has a strong correlation with clinical disability in both RRMS and progressive MS. Greater spinal cord atrophy was seen in patients with progressive than relapsing-remitting MS. CSA-C2, disease duration, and phenotype are independent predictors of disability.