cssi/SciSciGPT-SciSciNet huggingface dataset:
Audiogenic seizures following global ischemia induced by chest compression in Long-Evans rats

Transient global ischemia was used to produce a rat model of generalized tonic-clonic epilepsy. Controlled chest compression in ketamine-anesthesized Long-Evans rats produced transient global ischemia by mechanically preventing the heart from pumping blood. Circulation was restored by standard cardiopulmonary resuscitation techniques. With a temporal muscle (skull) temperature of 35 +/- 0.4 degrees C, 75% (76/102) of the rats survived 7 min of chest compression. Generalized seizures could be evoked in 78% (59/76) of the surviving rats by a 60 s exposure to a loud sound (bell, 110 dB) beginning 24 h after the ischemic episode. The seizure patterns seen resembled those described by Maresceaux (1987) for genetically seizure-prone Wistar rats. Susceptibility to sound-induced seizures declined with time, with wide variations in recovery rate between individuals; one rat showed a daily sound-induced seizure for over 5 months. Seizures were attenuated or blocked by treatment with carbamazepine or sodium valproate. This model is similar to the great vessel occlusion model used by Kawai et al. (1995), but is less invasive. We believe it will be useful in the evaluation of therapies for acquired generalized (grand mal) seizures.
Analyzing Mathematical Tasks: A Catalyst for Change?

In this study we investigate a strategy for engaging high school mathematics teachers in an initial examination of their teaching in a way that is non-threatening and at the same time effectively supports the development of teachers’ pedagogical content knowledge [Shulman (1986). Educational Researcher, 15(2), 4–14]. Based on the work undertaken by the QUASAR project with middle school mathematics teachers, we engaged a group of seven high school mathematics teachers in learning about the Levels of Cognitive Demand, a set of criteria that can be used to examine mathematical tasks critically. Using qualitative methods of data collection and analysis, we sought to understand how focusing the teachers on critically examining mathematical tasks influenced their thinking about the nature of mathematical tasks as well as their choice of tasks to use in their classrooms. Our research indicates that the teachers showed growth in the ways that they consider tasks, and that some of the teachers changed their patterns of task choice. Further, this study provides a new research instrument for measuring teachers’ growth in pedagogical content knowledge.
Severe sensitivity to ultraviolet radiation in an Arabidopsis mutant deficient in flavonoid accumulation

A mutantArabidopsis thaliana L., which displays a dramatic increase in sensitivity to ultraviolet-B (UV-B) radiation compared with wild-type plants, has been isolated by chemical mutagenesis. This mutation appears to affect UV-tolerance specifically, since mutant plants are indistinguishable from wild type with respect to their degree of resistance to other forms of stress. The UV-sensitive mutation proved to be recessive and to segregate as a single Mendelian locus. This single gene defect was shown to lead to a block in the synthesis of a group of flavonoids which normally accumulate in developing wild-typeArabidopsis and which increase in concentration when plants are exposed to UV radiation. One of these compounds has been identified as a rhamnosylated derivative of the flavonol, kaempferol. The results suggest that one or more of the flavonoids whose production has been blocked in the UV-sensitive mutant is essential for the protection of Arabidopsis against UV-radiation damage. This constitutes further evidence that flavonoids play an important role in the protection of plants from the damaging effects of UV-B light.
Preliminary Experience With A Charged Selenium Plate Projection X-Ray System

Electrostatic imaging techniques provide the means to record x-ray images without the use of film. The conventional screen-film photon receptor is replaced by a charged selenium-oxide plate. After exposure, the plate is scanned with multiple electrometer probes forming a 1024x1024x12 bit digital image from the latent electrostatic image. This imaging modality represents an early entry into the era of true digital radiography, evolving toward a filmless diagnostic imaging facility. This paper discusses the architecture of an experimental charged selenium plate projection digital x-ray system. As well as some preliminary results of the characteristics of a amorphous selenium plate photon receptor exposed to visible light.© (1984) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Abnormal Amygdala and Prefrontal Cortex Activation to Facial Expressions in Pediatric Bipolar Disorder

Objective Previous functional magnetic resonance imaging (fMRI) studies in pediatric bipolar disorder (BD) have reported greater amygdala and less dorsolateral prefrontal cortex (DLPFC) activation to facial expressions compared to healthy controls. The current study investigates whether these differences are associated with the early or late phase of activation, suggesting different temporal characteristics of brain responses. Method A total of 20 euthymic adolescents with familial BD (14 male) and 21 healthy control subjects (13 male) underwent fMRI scanning during presentation of happy, sad, and neutral facial expressions. Whole-brain voxelwise analyses were conducted in SPM5, using a three-way analysis of variance (ANOVA) with factors group (BD and healthy control [HC]), facial expression (happy, sad, and neutral versus scrambled), and phase (early and late, corresponding to the first and second half of each block of faces). Results There were no significant group differences in task performance, age, gender, or IQ. Significant activation from the main effect of group included greater DLPFC activation in the HC group, and greater amygdala/hippocampal activation in the BD group. The interaction of Group × Phase identified clusters in the superior temporal sulcus/insula and visual cortex, where activation increased from the early to late phase of the block for the BD but not the HC group. Conclusions These findings are consistent with previous studies that suggest deficient prefrontal cortex regulation of heightened amygdala response to emotional stimuli in pediatric BD. Increasing activation over time in superior temporal and visual cortices suggests difficulty processing or disengaging attention from emotional faces in BD.
Impact of hepatectomy surgical complexity on outcomes and hospital quality rankings.

Background There is substantial variation in the surgical complexity of hepatectomy. Currently, the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) risk adjusts for hospital quality comparisons using only the primary procedure code. Our objectives were to (1) assess the association between secondary procedures and complications; (2) assess model performance with inclusion of surgical complexity adjustment; and (3) examine whether secondary procedures affect hospital quality rankings.
The 16th Annual Intelligent Ground Vehicle Competition: intelligent students creating intelligent vehicles

The Intelligent Ground Vehicle Competition (IGVC) is one of three, unmanned systems, student competitions that were founded by the Association for Unmanned Vehicle Systems International (AUVSI) in the 1990s. The IGVC is a multidisciplinary exercise in product realization that challenges college engineering student teams to integrate advanced control theory, machine vision, vehicular electronics and mobile platform fundamentals to design and build an unmanned system. Teams from around the world focus on developing a suite of dual-use technologies to equip ground vehicles of the future with intelligent driving capabilities. Over the past 16 years, the competition has challenged undergraduate, graduate and Ph.D. students with real world applications in intelligent transportation systems, the military and manufacturing automation. To date, teams from nearly 70 universities and colleges have participated. This paper describes some of the applications of the technologies required by this competition and discusses the educational benefits. The primary goal of the IGVC is to advance engineering education in intelligent vehicles and related technologies. The employment and professional networking opportunities created for students and industrial sponsors through a series of technical events over the four-day competition are highlighted. Finally, an assessment of the competition based on participation is presented.
Image retrieval with templates of arbitrary size

We study the problem of retrieving images using a small template. The goal is to allow a user to search for images containing a pattern similar to the template, adding to the capability of a search engine. We propose to employ a segmentation-based approach. As a specific example, we introduce a quadtree segmentation technique for textured images and a distance measure, Sum of Minimum Distance, suitable for template-based image retrieval applications.
Scanning and Escape during Protein-disulfide Isomerase-assisted Protein Folding

During oxidative protein folding, efficient catalysis of disulfide rearrangements by protein-disulfide isomerase is found to involve an escape mechanism that prevents the enzyme from becoming trapped in covalent complexes with substrates that fail to rearrange in a timely fashion. Protein-disulfide isomerase mutants with only a single active-site cysteine catalyze slow disulfide rearrangements and become trapped in a covalent complex with substrate. Escape is mediated by the second, more carboxyl-terminal cysteine at the active site. A glutathione redox buffer increases the kcat for single-cysteine mutants by 20–40-fold, but the presence of the second cysteine at the active site in the wild-type enzyme increases the kcat by over 200-fold. A model is developed in which kinetic scanning for disulfides of increasing reactivity is timed against an intramolecular clock provided by the second cysteine at the active site. This provides an alternative, more efficient mechanism for rearrangement involving the reduction and reoxidation of substrate disulfides.
Pluripotent mesenchymal stem cells reside within avian connective tissue matrices

Recent studies have noted the presence of putative stem cells derived from the connective tissues associated with skeletal muscle, heart, and dermis. Long-term continuous cultures of these cells from each tissue demonstrated five distinct phenotypes of mesodermal origin, i.e. muscle, fat, cartilage, bone, and connective tissue. Clonal analysis was performed to determine whether these morphologies were the result of a mixed population of lineage-committed stem cells or the differentiation of pluripotent stem cells or both. Putative stem cells from four tissues (skeletal muscle, dermis, atria, and ventricle) were isolated and cloned. Combined, 1158 clones were generated from the initial cloning and two subsequent subclonings. Plating efficiency approximated 5.8%. Approximately 70% of the 1158 clones displayed a pure stellate morphology, while the remaining clones contained a mixture of stellate, chondrogenic- or osteogenic-like morphologies or both. When cultured in the presence of dexamethasone, cells from all clones differentiated in a time- and concentration-dependent manner into muscle, fat, cartilage, and bone. These results suggest that pluripotent mesenchymal stem cells are present within the connective tissues of skeletal muscle, dermis, and heart and may prove useful for studies concerning the regulation of stem cell differentiation, wound healing, and tissue restoration, replacement and repair.
Error and Feedback: Relation between Content Analysis and Confidence of Response

Prior studies using science concepts and rules have indicated that learners spend twice as much time studying feedback after fine discrimination errors as they do after gross errors. Likewise, other researchers have suggested that learners had longer feedback study times after errors for which they had a high confidence that the response was correct. The purpose of the present study was to see if a relationship between discrimination error (based on content analysis) and confidence in response (based on self-report) could be established. Analysis indicated that, as in prior studies, the correlation between fine discrimination error and feedback study time was positive. The correlation between fine discrimination error and confidence in response, however, was negative. Possible explanations for these results are discussed.
Unitarity Corrections to Born Amplitudes for Nucleon-Nucleon Scattering

A correction scheme applied to Born amplitudes for calculating the resonance contributions to the larger lowangular-momentum phase shifts in nucleon- nucleon scattering is proposed. Calculated results for /sup 1/P/sub 1/, /sup 1/D/ sub 2/, and /sup 1/F/sub 3/ nucleon-nucleon phase shifts are tabulated. (L.B.S.)
Continued Observations on the Role of Steroid Therapy in Tuberculosis

This therapy is based upon experimental evidence that cortisone will bring about a reduced reaction to tuberculoprotein in a tuberculinsensitized animal. As a result, there is a diminution in exudate, a delay in tissue destruction, and the formation of fewer fibroblasts. At the same time, however, poorer localization of the infection and an increased multiplication of tubercle bacilli occurs.15 A combination of adequate chemotherapy with the steroid should control these dangers, however, and still allow the beneficial anti-inflammatory effects.#{176}7In fact, chemotherapeutic agents are most effective when tubercle bacilli are actively multiplying and, theoretically, the decrease in exudate should permit the drugs to reach the organisms more readily.
The inhibition of iodide uptake in the thyroid gland by the fluorescent dye, ans

Abstract The presence of ANS (l-anilino-8-napthalenesulfonate) in the bathing medium of porcine thyroid slices has a strong effect on the accumulation of iodide in the slices as given by the T/M, i.e., the ratio of iodide concentration in the slice to that present in the medium. The ANS lowers the T/M with a possible effect at concentrations as low as 10 −5 M ANS; at 10 −2 M ANS, the T/M approaches l. The concentration of ANS necessary to attain at 50% decrease in T/M is about 10 −4 M. In the absence of ANS, the T/M value peaks at about 3 hours incubation and then slowly decreases; in the presence of ANS, the value reaches a maximum at l hour and remains at this value for several hours. The efflux of iodide from the gland is not affected by the ANS nor does the ANS have a measurable effect on the oxygen consumption of the slices. Inhibition of ATPase activity by ANS, suggests that ATPase inhibition may partially account for the lowering of T/M by ANS, however, the evidence is not compelling. The inhibition of iodide transport by dyes is considered in terms of a model, relating dye structure to location of the dye in phospholipid vesicles and thyroid cell plasma membranes, proposed by the authors ( Chem. Phys. Lipids 181-198).
ONCE-DAILY DOSING OF AMINOGLYCOSIDE ANTIBIOTICS

The aminoglycosides are a class of bactericidal antibiotics characterized by the presence of a six-carbon aminocyclitol ring covalently bonded to multiple amino sugar groups. 24 Aminoglycosides commonly used for the treatment of serious bacterial infections in the United States include gentamicin, tobramycin, amikacin, netilmicin, and streptomycin. 18 These drugs act in part by impairing bacterial protein synthesis through irreversible binding to the 30S subunit of the bacterial ribosome. 24 Since the introduction of streptomycin in the 1940s, aminoglycosides have proved extremely useful in the treatment of infections caused by gram-negative bacilli, including Pseudomonas aeruginosa, and infections caused by staphylococci, mycobacteria, and several other pathogens. 18 The Food and Drug Administration (FDA) approved dosing regimens for aminoglycoside antibiotics require multiple daily doses in individuals with normal renal function. Improvements in the understanding of the pharmacodynamics of aminoglycoside efficacy and mechanisms of toxicity, however, have prompted the evaluation of once-daily dosing regimens in clinical studies. In the pages that follow, we review the rationale behind once-daily dosing of aminoglycoside therapy as well as clinical data on the efficacy and toxicity of once-daily dosing of aminoglycosides. We also review practical aspects of dosing and monitoring once-daily aminoglycoside therapy and issues complicating the use of these regimens in special populations (including children, adults with an altered volume of distribution for aminoglycosides, and individuals with renal dysfunction) and in certain illnesses (including bacterial endocarditis, neutropenia and fever, and cystic fibrosis).
PROMISES AND DILEMMAS OF PARTICIPATION: ACTION RESEARCH, SEARCH CONFERENCE METHODOLOGY, AND COMMUNITY DEVELOPMENT

Participatory approaches currently occupy a prominent position in community development practice. However, despite the claims made for the benefits of participation for community members and practi...
Innate lymphoid cells sweeten the pot

Our intestines are brimming with a dense community of microorganisms that number in the trillions. This microbiota includes bacteria that metabolize dietary carbohydrates that would otherwise evade digestion. Although most gut bacteria are beneficial, problems can arise if the community changes dramatically or if bacteria invade deeper tissues. The intestine has therefore evolved strategies to control this ecosystem. One such strategy involves the synthesis of cell surface carbohydrate chains that can be used as a food source by the microbiota. On page 1310 of this issue, Goto et al. ( 1 ) show that specific immune cells trigger the synthesis of these carbohydrate chains in the epithelial lining of the intestine.
Recent advances in parathyroid hormone research

The introduction of blood calcium determinations as part of routine health screening procedures in this country has led to the discovery of a much higher incidence of primary hyperparathyroidism than was recognized previously. Research efforts have focused on studies of the cellular defects in the regulation or parathyroid hormone biosynthesis and secretion that are characteristically found in adenomatous and hyperplastic parathyroid glands. The available evidence indicates that the secretory defect probably resides at two levels: (1) a defect in the calcium sensor of the abnormal glands ("set-point" error) and (2) an exaggeration of a small component of autonomous hormone secretion that becomes relevant due to the large mass of glandular tissue. Regulation of parathyroid hormone synthesis appears to be at the level of cell replication (hyperplasia) and at the level of intracellular turnover of hormone. Marked heterogeneity of hormone in the circulation arises as a result of both glandular and extraglandular cleavages of hormone and the predominant circulating form of the hormone are biologically inactive, COOH-terminal fragments. Because most cases of hypercalcemia that accompany cancer are caused by humoral substances other than COOH-terminal fragments should distinguish patients with hypercalcemia due to cancer from those with primary hyperparathyroidism.
Lung development in the fetal primate Macaca nemestrina. III. HMD.

Summary: Delivery of M. nemestrina at 80% of normal gestation provides a population of neonates at high risk for hyaline membrane disease (HMD). The diagnosis of HMD was made by the presence of reticulogranular densities and air bronchograms on chest radiographs. Patchy atelectasis was seen in the lungs of animals assigned by clinical and radiographic criteria to the HMD group and not in the normal lungs of animals matched for gestational and postnatal age. Total phospholipid and phosphatidylcholine in whole lung, airway lavage fluid, and surface-active materials were lower in animals with HMD. Amniotic fluid L/S ratios were lower in the group that developed HMD. Pressure-volume measurements indicated decreased distensibility and unstable terminal air spaces in the HMD group. Alveolar-arterial oxygen pressure differences were greater in animals with HMD. There were no differences between HMD and normal groups in body weight, lung weight, percent dry lung weight, gestational age, and postnatal age at death. This primate species, subjected to premature delivery, is a suitable animal model of HMD in human neonates.
Multiple lead electrocardiograms in angina pectoris.

Abstract The increased general use of unipolar limb and multiple precordial leads makes it desirable to re-evaluate the role of electrocardiography in medical practice. In the present study the twelve lead electrocardiograms (three standard, three augmented unipolar limb, and six unipolar precordial leads) of patients with uncomplicated angina pectoris are compared with those of a group of subjects similar in age but without clinical symptoms or signs of heart disease. The purpose is to determine what such tracings show in patients with angina pectoris and to differentiate these findings from those of patients with acute myocardial infarction on the one hand and those with no symptoms or signs of heart disease on the other. The changes in Q, RS-T, and T characteristic of acute myocardial infarction are well known and are of considerable diagnostic importance when well defined and progressive. When such findings are borderline, however, their significance is difficult to evaluate. For example, small Q waves, slight elevation or depression of RS-T segments, or low amplitude T waves may represent: (1) the earliest objective evidence of acute myocardial infarction; (2) the only residual evidence of past infarction; (3) myocardial disease without infarction; or (4) they may occur in the absence of myocardial damage. The limits and variations of normal in unipolar limb and precordial electrocardiograms have not been established with certainty, and the frequency of borderline tracings in apparently normal adults is not well known. Until sufficient experience has accumulated to be certain of these fundamentals, it is possible that the significance of minor changes may be overemphasized. Not uncommonly, unipolar limb and multiple precordial leads are obtained only when cardiac disease is suspected. This may result in inadequate experience with the normal variations.
Cluster hull algorithms for large systems with small memory requirement

Improved hull walking algorithms for two-dimensional percolation are proposed. In these algorithms a walker explores the external perimeter of percolation clusters. With our modifications very large systems (sizeL) can be studied with finite and small memory requirement and in computation time τ∼L7/4. Applications in determining spanning probabilities, continuum percolation, and percolation with nonuniform occupation probability are pointed out.
Microscale Heat Transfer Transduced by Surface Plasmon Resonant Gold Nanoparticles.

Visible radiation at resonant frequencies is transduced to thermal energy by surface plasmons on gold nanoparticles. Temperature in ≤10-microliter aqueous suspensions of 20-nanometer gold particles irradiated by a continuous wave Ar+ ion laser at 514 nm increased to a maximum equilibrium value. This value increased in proportion to incident laser power and in proportion to nanoparticle content at low concentration. Heat input to the system by nanoparticle transduction of resonant irradiation equaled heat flux outward by conduction and radiation at thermal equilibrium. The efficiency of transducing incident resonant light to heat by microvolume suspensions of gold nanoparticles was determined by applying an energy balance to obtain a microscale heat-transfer time constant from the transient temperature profile. Measured values of transduction efficiency were increased from 3.4% to 9.9% by modulating the incident continuous wave irradiation.
Methods of deconditioning persisting avoidance: Amphetamine, chlorpromazine, and chlordiazepoxide as adjuncts to response prevention

Rats were given extended avoidance training in an automated one-way avoidance chamber, a chamber with a retractable ledge. After training and footshock termination, some rats were prevented from responding by being trapped on the footshock grid with the ledge removed. During this response prevention, rats were under the influence of either amphetamine, chlorpromazine, cnlordiazepoxide, or a placebo. Subsequently, rats were tested for continuance of responding when footshock no longer occurred. Only response prevention with amphetamine reduced persisting avoidance responding compared to no treatment.
Relativistic Quantum Scars

The concentrations of wave functions about classical periodic orbits, or quantum scars, are a fundamental phenomenon in physics. An open question is whether scarring can occur in relativistic quantum systems. To address this question, we investigate confinements made of graphene whose classical dynamics are chaotic and find unequivocal evidence of relativistic quantum scars. The scarred states can lead to strong conductance fluctuations in the corresponding open quantum dots via the mechanism of resonant transmission.
Liquid Deposition at Micro and Nanoscale

Micro/Nanolithography is a creation of micro/nano features on the substrate. This paper proposes a new capillary-based lithography method that is non-invasive to substrate. The application of the pressure from one side of capillary causes the liquid meniscus to form at the capillary outlet. Touching the substrate with the meniscus only causes the liquid deposition on the substrate. The size of deposited liquid droplet is about 10% of inner diameter of the capillary. Glycerol was chosen as a trial liquid of deposition, because the rate of evaporation for glycerol is low in comparison with other liquids. The deposition of glycerol was done in micro-scale. Comparison of theoretical results with experimental data is shown and discussed.Copyright © 2010 by ASME
Effect of Micellization on Rate of Cupric-Ion-Promoted Hydrolysis of Dicarboxylic Acid Hemiesters

The effect of micellar sodium lauryl sulfate on the rate of cupric-ion-promoted hydrolysis of some dicarboxylic acid hemiesters was investigated at pH 5, ionic strength 0.1 M, and 40, 45, and 50°. The rate of cupric-ion-promoted hydrolysis of sodium n-decyl oxalate in the micellar phase is about 50 times as fast as that in the bulk solution. The formation constant of the intermediate chelate complex, cupric decyl oxalate, was decreased in the micellar phase, while the rate of attack of hydroxide ion upon the chelate complex was increased. The overall rate increase is attributed to the increase in the entropy of activation for the reaction in the micellar phase. The rates of hydrolysis of sodium hydrocortisone 21-hemisuccinate and sodium hydrocortisone 21-hemi-(3,3-dimethylglutarate) were unaffected by copper ion.
Simulation-based response surface computation in the presence of monotonicity

In many stochastic models, it is known that the response surface corresponding to a particular performance measure is monotone in the underlying parameter. For example, the steady-state mean waiting time for customers in a single server queue is known to be monotone in the service rate. In other contexts, the simulator may believe, on the basis of intuition, that the response surface is monotone. This paper describes an appropriate methodology for incorporating such monotonicity constraints into one's response surface estimator.
Regenerative changes in rat dorsal roots following wallerian degeneration

Regeneration of nerves has been studied following crush lesions made in the dorsal roots of the cauda equina of rats, which subsequently were sacrificed at appropriate intervals. Some Schwann cell multiplication occurred during the first few days. Schwann cells also became somewhat mobile, but their movements were guided and confined by persistent basement membrane (neurilemmal) envelopes. The latter no doubt played a key role in the organization and orderly development of “Buengner bands”. Extracellular spaces developed within these envelopes, and regenerating axons appeared within them as soon as 4 days after a lesion had been produced. Singly and in groups they were at first seen between the basement membrane investments and the Schwann cells, without being embedded in the latter. Secondarily, gutters formed in the Schwann cell cytoplasm and the axons became embedded. Beginning remyelinization of axons was evident as early as 7 days after formation of a lesion. This often started in Schwann cells which still contained much degenerating myelin from the original sheath. Commonly multiple axons appeared in Schwann cells that originally had been associated with myelinated axons. Evidence is presented that supernumerary new axons were suppressed, however, for eventually the normal relationship of a single myelinated axon to a Schwann cord was reestablished in most instances. Myelinization had by no means been completed 1 month after the lesion was established, although it was substantially so after 2 months, when other features of the damaged nerve bundle had also returned nearly to normal patterns.
A new anatomic variant of the aorta: A case report

Anatomic anomalies of the infrarenal aorta and iliac arteries are rare. We report a 39-year-old man who presented with an ileo-cecal fistula secondary to Crohn disease. A computed tomography scan and subsequent arteriography noted his aorta bifurcated immediately inferior to the main renal arteries, at the level of the second lumbar vertebrae. Associated vascular anomalies included a common superior mesenteric artery/celiac axis plus multiple renal arteries. To our knowledge, this is the first report of this aortic anomaly in the literature.
Statistical computing and graphics in Opasnet MediaWiki

Wikisystems are good for producing text and documents in collaborative manner. We want to extend this to cover mathematical model building as well. In our demonstration we will show how R (statistical software) can be integrated into Mediawiki as an extension (R-Tools) and how it can be used directly from wiki pages. This extension enables users to write R-code, run it and see the results of the calculation on the wiki page. R-tools can use data from external databases and this functionality is also demonstrated.
Core noise source diagnostics on a turbofan engine using correlation and coherence techniques

Fluctuating pressure measurements at several locations within the core of a turbofan engine were made simultaneously with far field acoustic measurements. Correlation and coherence techniques were used to determine the relative amplitude and phase relationships between core pressures at these various locations and between the core pressures and far field acoustic pressure. The combustor is a low frequency source region for acoustic propagation through the core nozzle and out to the far field. The relation between source pressure and the resulting sound pressure involves a 180 degree phase shift and an amplitude transfer function which varies approximately as frequency squared. This is consistent with a simplified model using fluctuating entropy as a source term.
The Economics of Director Heterogeneity

We investigate the potential costs and benefits of firms constituting a heterogeneous pool of directors relative to more homogeneous boards. We measure director heterogeneity along six separate dimensions and divide board heterogeneity into occupational and social components. Our empirical analysis indicates that corporate complexity and managerial control exhibit significant influence on board heterogeneity. Using the heterogeneity of the county population of the firm’s headquarters as an instrument, we also find that investors place valuation premiums on heterogeneous boards in complex firms but discount heterogeneity in less complex firms. Overall, our analysis indicates greater heterogeneity may not necessarily improve board efficacy. Government agencies, shareholder groups, and social activists frequently advocate and call for greater heterogeneity among directors on corporate boards. Proponents of greater board heterogeneity argue that managers and firms benefit from directors bringing diverse social and occupational viewpoints to the boardroom. Large international firms such as PepsiCo and Aon Corp indicate social heterogeneity among directors proves helpful in developing new products and strategies. 1 A 1995 Catalyst (2004) survey found that Fortune 500 chief executive officers (CEOs) considered director heterogeneity an important “bottom-line” or profitability consideration. Activist investor groups such as Catalyst, ICCR, and TIAA-CREF argue that homogeneous boards composed of the CEO’s own peers may be less effective advisors and monitors. In early 2009, the California Public Employees Retirement System issued a report indicating that board diversity leads to greater shareholder returns and firm profitability. Yet, the push for less uniformity in the boardroom may be driven by social or ethical reasons rather than firm profitability (Agrawal and Knoeber, 2001). Farrell and Hersch (2005) examine gender heterogeneity and find women board members have no influence on firm performance. They argue that firms simply include members of minority groups to build a public image of inclusiveness or tokenism. In contrast, Adams and Ferreira (2009) state that gender diversity has a positive and significant impact on board effectiveness. In a general analysis using a large survey of 30,000 interviews from the United States, Putnam (2007) reports that heterogeneity among individuals decreases cooperation, impedes communication, and leads to social loafing. Board
Evidence for a single electron transfer mechanism in reactions of lithium diorganocuprates with organic halides

Abstract It has been demonstrated by means of spectroscopic studies involving cyclizable alkyl halides that lithium dimethylcuprate can react with organic halides by a single electron transfer pathway.
The effect of temperature abuse on Clostridium perfringens in cooked turkey stored under air and vacuum

Abstract The potential for growth of Clostridium perfringens in aerobic and anaerobic (vacuum) packaged cooked ground turkey was investigated. Samples of autoclaved ground turkey were inoculated with ∼3·0 log 10 cfu g -1 of C. perfringens strain NCTC 8238 or NCTC 8239, packaged and stored at various temperatures. Vegetative growth and heat-resistant spores were enumerated by plating unheated and heated (75°C for 20 min) samples, respectively, on tryptose-sulfite-cycloserine agar. The type of atmosphere influenced the growth of C. perfringens at 15 and 28°C. Both strains grew to about 7 logs within 9 h anaerobically and by 24 h aerobically at 28°C. While aerobic growth was slow at 15°C, mean log 10 cfu g -1 increased anaerobically by 4-4·5 logs by day 8 for both strains. Spores were not found at 4 and 15°C, but were detected as early as 24 h at 2°C under anaerobic conditions in both strains. C. perfringens population stabilized or slowly decreased at 4°C. Cyclic and static temperature abuse of refrigerated products for 5 h will not permit C. perfringens growth. However, temperature abuse of such products for relatively long periods may lead to high and dangerous numbers of organisms. Reheating such products to an internal temperature of 65°C before consumption would prevent food-poisoning since the vegetative cells were killed.
A long-lived lunar dynamo driven by continuous mechanical stirring

Lunar rocks contain a record of an ancient magnetic field that seems to have persisted for more than 400 million years and which has been attributed to a lunar dynamo. Models of conventional dynamos driven by thermal or compositional convection have had difficulty reproducing the existence and apparently long duration of the lunar dynamo. Here we investigate an alternative mechanism of dynamo generation: continuous mechanical stirring arising from the differential motion, due to Earth-driven precession of the lunar spin axis, between the solid silicate mantle and the liquid core beneath. We show that the fluid motions and the power required to drive a dynamo operating continuously for more than one billion years and generating a magnetic field that had an intensity of more than one microtesla 4.2 billion years ago3 are readily obtained by mechanical stirring. The magnetic field is predicted to decrease with time and to shut off naturally when the Moon recedes far enough from Earth that the dissipated power is insufficient to drive a dynamo; in our nominal model, this occurred at about 48 Earth radii (2.7 billion years ago). Thus, lunar palaeomagnetic measurements may be able to constrain the poorly known early orbital evolution of the Moon. This mechanism may also be applicable to dynamos in other bodies, such as large asteroids.
Comparison of medium frequency propagation characteristics of a transmission line measured from both ends in a coal mine entry

An underground coal mine medium frequency (MF) communication system generally couples its electromagnetic signals to a long conductor in a tunnel (entry). The entry plus the conductor acts as a transmission line (TL). Transceivers exchange signals along the line. The propagation characteristics of the TL, which is generally the longest signal path, play a major role in determining the system performance. In this paper, we present MF measurements of TL characteristics as measured from both ends of the TL in a coal mine entry. The characteristic impedances from both ends have some significant differences, but the other propagation parameters are very similar.
SIGNATURE: a workbench for gene expression signature analysis.

The biological phenotype of a cell, such as a characteristic visual image or behavior, reflects activities derived from the expression of collections of genes. As such, an ability to measure the expression of these genes provides an opportunity to develop more precise and varied sets of phenotypes. However, to use this approach requires computational methods that are difficult to implement and apply, and thus there is a critical need for intelligent software tools that can reduce the technical burden of the analysis. Tools for gene expression analyses are unusually difficult to implement in a user-friendly way because their application requires a combination of biological data curation, statistical computational methods, and database expertise. We have developed SIGNATURE, a web-based resource that simplifies gene expression signature analysis by providing software, data, and protocols to perform the analysis successfully. This resource uses Bayesian methods for processing gene expression data coupled with a curated database of gene expression signatures, all carried out within a GenePattern web interface for easy use and access. SIGNATURE is available for public use at http://genepattern.genome.duke.edu/signature/ .
Prolonged Cardiac Monitoring for Detection of Paroxysmal Atrial Fibrillation After Cerebral Ischemia

Atrial fibrillation (AF) is a common arrhythmia, and its prevalence continues to rise with the aging of the population.1 It is the most frequent cause of ischemic stroke in elderly patients.2 Strokes from AF tend to be more severe and disabling.3 Consequently, the societal effect of AF-related strokes is large. Despite advances in our understanding of stroke mechanisms, 20% to 30% of all strokes remain cryptogenic.4 Many of them have an embolic pattern on brain imaging and, therefore, an occult embolic source is suspected. Reported rates of cryptogenic stroke recurrence vary across cohorts but may be high.5 On the basis of current evidence, we found that patients with cryptogenic stroke or transient ischemic attack (TIA) are generally treated with antiplatelet therapy and control of vascular risk factors.6 Although this therapeutic strategy is adequate for arterial sources of embolism, it might be insufficient if a cause of cardiac embolism has been missed. AF is often paroxysmal and asymptomatic.7 In fact, paroxysmal AF (PAF) may be more prevalent than persistent AF among patients with stroke. In a large study of consecutive patients with TIA or stroke, nearly two thirds of cases of AF were paroxysmal.8 PAF carries the same risk of stroke as persistent AF.9 Brief, asymptomatic episodes of PAF can be difficult to detect by conventional methods (ie, ECG, Holter monitoring of short duration, patient-activated loop recorders). Thus, occult PAF is a likely candidate to explain at least some cases of cryptogenic stroke or TIA.10 This is particularly important because oral anticoagulation might be indicated in these cases. Recent technological advances have made it possible to monitor for PAF in the ambulatory setting for prolonged periods of time (weeks, months, and even years). These devices are extremely sensitive and can uncover …
An impedance study of a carbon fiber/vinyl ester composite

Abstract The electrochemical behavior of a carbon fiber/vinyl ester composite in 3.5% NaCl solution was investigated. The technique chosen for the study was electrochemical impedance spectroscopy (...
Permeability assessment of the focused ultrasound-induced blood-brain barrier opening using dynamic contrast-enhanced MRI.

Focused ultrasound (FUS) in conjunction with microbubbles has been shown to successfully open the blood–brain barrier (BBB) in the mouse brain. In this study, we compute the BBB permeability after opening in vivo. The spatial permeability of the BBB-opened region was assessed using dynamic contrast-enhanced MRI (DCE-MRI). The DCE-MR images were post-processed using the general kinetic model (GKM) and the reference region model (RRM). Permeability maps were generated and the Ktrans values were calculated for a predefined volume of interest in the sonicated and the control area for each mouse. The results demonstrated that Ktrans in the BBB-opened region (0.02 ± 0.0123 for GKM and 0.03 ± 0.0167 min−1 for RRM) was at least two orders of magnitude higher when compared to the contra-lateral (control) side (0 and 8.5 × 10−4 ± 12 × 10−4 min−1, respectively). The permeability values obtained with the two models showed statistically significant agreement and excellent correlation (R2 = 0.97). At histological examination, it was concluded that no macroscopic damage was induced. This study thus constitutes the first permeability assessment of FUS-induced BBB opening using DCE-MRI, supporting the fact that the aforementioned technique may constitute a safe, non-invasive and efficacious drug delivery method.
Employee engagement: an examination of antecedent and outcome variables

This correlational study (n = 283) examined the links between job fit, affective commitment, psychological climate, and employee engagement, and the dependent variables, discretionary effort, and intention to turnover. An Internet-based survey battery of six scales was administered to a heterogeneous sampling of organizations from service, technology, healthcare, retail, banking, nonprofit, and hospitality fields. Hypotheses were tested through correlational and hierarchical regression analytic procedures. Job fit, affective commitment, and psychological climate were all significantly related to employee engagement, while employee engagement was significantly related to both discretionary effort and intention to turnover. For the discretionary effort model, the hierarchical regression analysis results suggested that the employees who reported experiencing a positive psychological climate were more likely to report higher levels of discretionary effort. As for the intention to turnover model, the hierarchi...
Paul Amar. The Security Archipelago: Human Security States, Sexuality Politics, and the End of Neoliberalism

In February 2011, the Egyptian military formed a transitional government to fill the vacuum left by President Hosni Mubarak's resignation and pledged to deepen democracy in the country. That same m...
Calcium kinetics in individual heart segments

The isolated, perfused rabbit heart was studied with reference to calcium decay and uptake in individual segments: atria, right ventricle, left ventricle, and septum. For each segment, calcium decay and uptake curves were obtained by direct tissue analysis for calcium. Fitting procedures established single exponential decay and single exponential uptake curves. Equilibrium values of calcium content, that is, pre-washout and post-uptake calcium contents, followed the order: atrial > right ventricular > left ventricular = septal. Except for the atria, the uptake rate constant for each segment was significantly larger than the decay rate constant. While no significant trend could be found for exponential decay rate constants, uptake rate constants followed the order: septal > left ventricular > right ventricular > atrial.
Calibration of passive microwave polarimeters that use hybrid coupler-based correlators

Four calibration algorithms are studied for microwave polarimeters that use hybrid coupler-based correlators: (1) conventional two-look of hot and cold sources; (2) three looks of hot and cold source combinations; (3) two-look with correlated source; and (4) four-look combining methods (2) and (3). The systematic errors are found to depend on the polarimeter component parameters and accuracy of calibration noise temperatures. A case study radiometer in four different remote sensing scenarios was considered in light of these results. Applications for ocean surface salinity, ocean surface winds, and soil moisture were found to be sensitive to different systematic errors. Finally, a standard uncertainty analysis was performed on the four-look calibration algorithm, which was found to be most sensitive to the correlated calibration source.
Runahead execution vs. conventional data prefetching in the IBM POWER6 microprocessor

After many years of prefetching research, most commercially available systems support only two types of prefetching: software-directed prefetching and hardware-based prefetchers using simple sequential or stride-based prefetching algorithms. More sophisticated prefetching proposals, despite promises of improved performance, have not been adopted by industry. In this paper, we explore the efficacy of both hardware and software prefetching in the context of an IBM POWER6 commercial server. Using a variety of applications that have been compiled with an aggressively optimizing compiler to use software prefetching when appropriate, we perform the first study of a new runahead prefetching feature adopted by the POWER6 design, evaluating it in isolation and in conjunction with a conventional hardware-based sequential stream prefetcher and compiler-inserted software prefetching. We find that the POWER6 implementation of runahead prefetching is quite effective on many of the memory intensive applications studied; in isolation it improves performance as much as 36% and on average 10%. However, it outperforms the hardware-based stream prefetcher on only two of the benchmarks studied, and in those by a small margin. When used in conjunction with the conventional prefetching mechanisms, the runahead feature adds an additional 6% on average, and 39% in the best case (GemsFDTD).