cssi/SciSciGPT-SciSciNet huggingface dataset:
Real-time optimal commutation for minimizing thermally induced inaccuracy in multi-motor driven stages

In this paper minimum power commutation laws of permanent-magnet synchronous linear motors are extended to multiple-motor driven systems. A system-wide view of commutation is shown to exploit the redundancy of motor coils and motor force generation that exist in over actuated motion platforms. We propose a novel commutation law, that is only realizable by a multiple-motor system view, which minimizes total power subject to the constraint that the thermal distortion at the motion platform work space, caused by the motor coil heating, is minimized. Due to the added constraint, there is no closed-form solution and the problem is shown to be non-convex. This problem solution is proven to be equally solved by the combination of an algebraic and convex problem. To realize the commutation laws, a custom embedded solver, using an interior-point method, is described to solve the convex problem in real-time and is shown to converge to a solution, in under 35 @ms, within the update rate of our system running at over 9 KHz.
Setting a gold standard for quantification of leukoaraiosis burden in patients with ischemic stroke: the Atherosclerosis Risk in Communities Study.

Abstract Background Accurate and reliable measurement of leukoaraiosis, or MR-detected white, matter hyperintensity (WMH) burden in subjects with acute ischemic stroke (AIS) is important for, ongoing research studies and future models of risk and outcome prediction, but the presence of a, cerebral infarct may complicate measurement. We sought to assess accuracy of a volumetric method, designed to measure WMH in AIS subjects as compared to the previously validated protocol. New method We randomly selected and equally sampled 120 brain scans from the Atherosclerosis, Risk in Communities (ARIC) MRI Study individuals within designated mild, moderate, and severe, tertiles of WMH volume (WMHV). T2 FLAIR axial images were analyzed using the AIS WMH volumetric, protocol and compared with the ARIC (gold standard) method. Pearson correlation coefficients, linear, concordance correlation coefficient, and Blant–Altman procedures were used to assess measurement, agreements between the two procedures. Results Median WMHV determined by using the ARIC method was 7.8 cm 3 (IQR 5.7–13.55) vs. 3.54 cm 3 , (IQR 2.1–7.2) using the AIS WMH method. There was good correlation between the two measurements, ( r = 0.52, 0.67, and 0.9 for tertiles 1, 2, and 3 respectively) ( p Comparison with existing method The AIS WMH protocol was specific for leukoaraiosis in ischemic, stroke, but it appeared to underestimate WMHV compared to the gold standard method. Conclusions Estimates of MR-detectable WMH burden using a volumetric protocol designed for, analysis of clinical scans correlate strongly with gold standard measurements. These findings will, facilitate future studies of WMH in normal aging and in patients with stroke and other cerebrovascular, disease.
Minimax optimal estimation of general bandable covariance matrices

Cai et al. (2010) [4] have studied the minimax optimal estimation of a collection of large bandable covariance matrices whose off-diagonal entries decay to zero at a polynomial rate. They have shown that the minimax optimal procedures are fundamentally different under Frobenius and spectral norms, regardless of the rate of polynomial decay. To gain more insight into this interesting problem, we study minimax estimation of large bandable covariance matrices over a parameter space characterized by a general positive decay function. We obtain explicit results to show how the decay function determines the minimax rates of convergence and the optimal procedures. From the general minimax analysis we find that for certain decay functions there is a tapering estimator that simultaneously attains the minimax optimal rates of convergence under the two norms. Moreover, we show that under the ultra-high dimension scenario it is possible to achieve adaptive minimax optimal estimation under the spectral norm. These new findings complement previous work.
LOCAL ANESTHESIA FOR UROLOGIC PROCEDURES

The ability to perform a variety of urologic procedures (urethrotomy, prostate surgery, penile prosthesis insertion, and bladder neck suspension) under local anesthesia in an outpatient setting is a significant advance in patient care. The surgical techniques are described that will allow the urologist to incorporate these procedures into practice.
Heterotypic smooth muscle cell/endothelial cell interactions differ between species.

Abstract Background. In vitro coculture models have been used to study heterotypic cell-cell interactions. This study was performed to determine if species of cell origin affects heterotypic smooth muscle cell (SMC) endothelial cell (EC) interactions in coculture. Methods. To study the effect of ECs on SMC proliferation, ECs were cultured on porous Dacron membranes. SMCs were added opposite the ECs or on bare membranes on Day 3, and after 4 days, cells were harvested for cell counts. To study the effect of SMCs on EC proliferation, ECs at a density of 5 × 10 5 cells/membrane were added to bare membranes or on membranes opposite SMCs plated 2 days earlier. After 48 h, cells were harvested for cell counts. ( N = 3/condition, experiments repeated ×2.) Cells of human and bovine aortic origin were used. Results. The effect of coculture on cell growth differed between species. The effect of heterotypic interactions between human cocultured cells was coinhibitory on the rate of growth as compared to the growth of cells cultured alone. Growth of cocultured ECs was 55.2 ± 8.7% less than that of ECs cultured alone while growth of cocultured SMCs was 27.2 ± 6.0% less than growth of SMCs cultured alone. This contrasted with the bovine EC stimulation of SMC proliferation, with 66.8 ± 5.0% greater growth of cocultured SMCs compared to SMCs cultured alone, and failure of bovine SMCs to decrease EC proliferation. Conclusions. Since significant differences in cell-material interactions occur in vivo between species, the finding that in vitro heterotypic cell-cell interactions are species dependent is not surprising. This fundamental difference in cell behavior stresses the potential importance of using human cells in studies evaluating cell-cell and cell-material interactions in vitro .
Reverse supply chain management and electronic waste recycling: a multitiered network equilibrium framework for e-cycling

In this paper, we develop an integrated framework for the modeling of reverse supply chain management of electronic waste, which includes recycling. We describe the behavior of the various decision-makers, consisting of the sources of electronic waste, the recyclers, the processors, as well as the consumers associated with the demand markets for the distinct products. We construct the multitiered e-cycling network equilibrium model, establish the variational inequality formulation, whose solution yields the material flows as well as the prices, and provide both qualitative properties of the equilibrium pattern as well as numerical examples that are solved using the proposed algorithm.
The effect of uncouplers of oxidative phosphorylation on lipid bilayer membranes: Carbonylcyanidem-chlorophenylhydrazone.

Detailed experimental data for conductivity and membrane potentials are presented for lecithin/cholesterol/decane bilayers in the presence of the uncoupler carbonylcyanidem-chlorophenylhydrazone (CCCP). These compare favorably with a theoretical model derived to explain the mechanism of action of uncouplers on bilayers. The model assumes that the weak acid uncoupler HA and its anion A− are the sole species which permeate the membrane. Its key feature is the recognition of the existence of unstirred aqueous layers on either side of the membrane. The model accounts for, among other things, a maximum in the transmembrane conductivity at a pH to the alkaline side of the uncoupler pKa and saturating current-voltage characteristics at high pH, both phenomena being found for CCCP. From a quantitative fit of model to data, values of 2.0×10−3 and 11 cm/sec are deduced for the permeability coefficients of the CCCP anion and the undissociated CCCP molecule, respectively.
ON THE CAUSE OF RAISED SERUM-AMYLASE IN DIABETIC KETOACIDOSIS

7 of 13 patients with diabetic ketoacidosis had raised serum-amylase concentrations. Isoenzymes analysis by polyacrylamide-gel electrophoresis showed that salivary-type amylases and not pancreatic-type amylases were responsible for the rise in 6 or the 7 cases. This demonstrates that the pancreas is usually not the origin of the increase in serum-amylase. Since salivary-type amylases are widely distributed in glandular epithelium, it is suggested that hyperamylasaemia in diabetic ketoacidosis is most often caused by systemic derangement of carbohydrate metabolism.
The Effectiveness of Sexual Victimization Prevention Among College Students: A Summary of "What Works"

Abstract During an academic year, between 3% and 10% of college women, nationally, experience rape; between 13% and 40% experience sexual victimization other than rape. A substantial proportion of these women are victimized repeatedly throughout their college years. Researchers and campus administrators know little about “what works” to reduce sexual victimization among college students. Evaluations suggest that most rape reduction programs improve students' knowledge and attitudes about rape but do not produce large, lasting reductions in sexual victimization. We review evaluations of college-based programs for preventing sexual victimization and highlight the most promising practices.
Inactivation of luciferase from the Luminous marine bacterium Beneckea harveyi by proteases: evidence for a protease labile region and properties of the protein following inactivation.

Abstract We have previously reported ( T. O. Baldwin, J. W. Hastings, and P. L. Riley, 1978 , J. Biol. Chem. , 253 , 5551–5554) that the proteolytic inactivation of the luciferase from the luminous marine bacterium Beneckea harveyi is due to hydrolysis of one or a small number of peptide bonds within the α subunit, and that following proteolytic inactivation, the molecular weight of the protein measured by sedimentation equilibrium is unaltered. We have continued these investigations and have made the following observations: (1) The proteaselabile region of the α subunit is about 20–25 residues in length, and located approximately 100–125 residues from one of the termini of the subunit; it possesses five to six trypsin-sensitive sites and two chymotrypsin-sensitive sites. (2) No binding could be measured between either the substrate, reduced flavin mononucleotide, or the product, oxidized flavin mononucleotide, and the luciferase inactivated with trypsin. (3) The results of sedimentation velocity measurements ( Holzman, T. F., and Baldwin, T. O., 1980 , Proc. Nat. Acad. Sci. USA , in press), reaction of the protein thiols with 5,5′-dithiobis(2-nitrobenzoic acid), and ultraviolet circular dichroism measurements suggest that following proteolytic inactivation, the luciferase has a slightly more expanded structure. (4) Analysis of a mutant luciferase, AK-6, having an α-subunit lesion that results in a red-shifted bioluminescence emission spectrum and a greatly reduced affinity for reduced flavin mononucleotide shows that alterations in the active center can result in a dramatically altered sensitivity to proteases, both in the rate of inactivation and in the sites of peptide bond hydrolysis.
Effects of chronic graded ethanol consumption on the metabolism, ultrastructure, and mechanical function of the rat heart

Three sequential sets of ethanolic rats (E) and their matched controls (C) were fed regular chow containing standard vitamins with the ethanol group in each series also receiving a progressively greater alcohol intake for 3 to 6 months: E1 5%, E2 10%, and E3 25% ethanol. Electron microscopy showed swelling of mitochondria, transverse tubules and sarcoplasmic reticulum, dehiscence of intercalated discs and disintegration of myofibrils scattered throughout the ventricular myocardium in E1 and E2 as early as 7 wk after beginning 5% ethanol; in addition, there were clumping of mitochondria and supercontraction of myofibrils in E3. Concomitant with substructural abnormalities in E3, there were slight but significant depressions of cardiac myofibrillar ATPase activity and mitochondrial function. Cardiac catecholamines, hydroxyproline, and total bound glycerol were unchanged. Alteration of isometric contraction of isolated, supported left ventricular papillary muscles occurred initially in E2 and was clearly evident in E3 by significant reduction of duration of systolic active state (time from onset to peak tension), while total tension generated and peak rate of tension rise were not yet disturbed. Extra vitamin supplementation in additional rats drinking 25% ethanol minimally lessened decline in myofibrillar ATPase activity, but otherwise provided no protection. Thus, chronic daily ingestion of graded quantities of ethanol representing 10 to 30% of total calories in well-nourished animals exerted toxic effects on microstructure, metabolism and mechanics of the ventricle. These alterations are postulated to be pertinent to early pathogenesis of clinical alcoholic cardiomyopathy.
Children learn separate aspects of speech production at different rates: Evidence from spectral moments

One theoretical perspective on speech development holds that segmental structure gradually emerges in the utterances of children as their first words, realized as roughly specified patterns of gesture, are differentiated into patterns of precisely specified and carefully coordinated gestures. The purpose of the present study was to test one aspect of this theoretical position, namely that children’s articulatory gestures are not as precisely specified as are those of adults. In addition, a related hypothesis was tested, namely that some patterns of gesture achieve adultlike precision sooner than others. To test these hypotheses, the first, third, and fourth spectral moments were derived for fricative (/s/ and /∫) and for stop‐burst (/t/ and /k/) noises in the speech samples of children (3 to 7 years of age) and of adults. First spectral moments for fricatives showed stronger consonant effects (i.e., /s/ vs /∫/) for adults’ than for children’s samples. This acoustic finding replicated a previous result [Ni...
Exceptions to the Rule Upwardly Mobile White and Mexican American High School Girls

While most high school students will obtain future social class positions consistent with their class backgrounds, a handful of students are exceptions to this rule, being either upwardly mobile working-class students (on the college preparatory track) or downwardly mobile middle-class students (on the vocational track). Highlighting predominant patterns, research typically ignores such students precisely because they are exceptions to the rule. This article, based on ethnographic research among white and Mexican American high school girls in California's Central Valley, foregrounds the experience of upwardly mobile working-class students showing how race/ethnicity, class, and gender intersect in the lives of these young women, shaping their educational mobility. Using a comparative approach, this article examines the similarities and differences between white and Mexican American working-class girls' experiences of mobility. The article first describes the various contingencies leading to the girls' mobi...
Beta-gamma directional correlation in the decay of 148Pm

Abstract The directional correlation involving the 1930 keV β-group in the decay of the 5.4 d 148 Pm and the 551 keV cascade γ-ray in 148 Sm has been measured at β-ray energies in the range 1050–1700 keV. The correlation coefficient A 2 is found to be small and positive ( A 2 ≈ + 0.02) in fair agreement with the expectations in the ξ-approximation and the work of Baba et al. The present results do not support the rather large negative values reported by Nainan and Moore. An attempt is made to interpret the data in terms of the β-decay matrix element. An essentially isotropic correlation is measured for the 1 − ( β )1 − ( γ )0 + cascade.
Existence of joint moments of stable random variables

Let X,, X,, . _, X,, be jointly e-stable random variables, 0 r: a < 2, and let pt. pz,. , pn be non-negative numbers.
Taming the Obesity Beast: Children, Marketing, and Public Policy Considerations

Abstract This essay explores the policy implications of the findings in this special section for potential remedies and opportunities for further research in the critical area of obesity. Children are an important focus here both because of the dramatic increase in childhood obesity in recent decades and because they lack the cognitive development and social experience to process marketing communications with the sophistication of adults. In addition, children's food purchase decisions are substantially influenced by their parents. Although packaged food marketers are setting their own voluntary restrictions on products to be marketed during entertainment content targeted at children, the impact of such restrictions is limited because children are substantial viewers of general entertainment content. This essay suggests that more prominent nutrition disclosure oriented toward obesity concerns for both packaged foods and fast-food restaurants should be more fully considered. It further suggests that increa...
Microstructure-Based Simulation of the Dielectric Properties of Polymer-Ceramic Composites for Capacitor Applications

Research on the microstructure-based modeling of composite dielectrics for capacitor applications is described. Methods for predicting the composite dielectric permittivity and internal electric field distributions within the microstructure using finite difference quasi-electrostatic modeling are described, along with methods of generating realistic model spaces of particulate microstructures. An existing algorithm for generating random, monosized spheres-in-a-dielectric matrix model spaces is modified to allow the treatment of bimodal composites in which small particles are deliberately segregated into the spaces between large particles. Such composites can have substantially higher total volumetric filling fractions of particles, leading to higher composite permittivity. The variations in permittivity with the filling fractions of bimodal inclusions are studied with the new model, with cases covering three different types of polymer matrix material. The effect of the small particle additions on the electric field statistics within the polymer matrix is also explored.
A thermophilic process for catechol production from phenol

A phenol tolerant thermophile,Bacillusstearothermophilus BR219, catabolizes phenol via a plasmid encoded catecholmeta pathway. Direct and selective inhibition of catechol 2,3-dioxygenase encoded in this pathway by tetracycline results in accumulation of the specialty chemical catechol. Optimal conditions for catechol production are presented.
Cannabinoid type 1 and type 2 receptor antagonists prevent attenuation of serotonin-induced reflex apneas by dronabinol in Sprague-Dawley rats.

The prevalence of obstructive sleep apnea (OSA) in Americans is 9% and increasing. Increased afferent vagal activation may predispose to OSA by reducing upper airway muscle activation/patency and disrupting respiratory rhythmogenesis. Vagal afferent neurons are inhibited by cannabinoid type 1 (CB1) or cannabinoid type 2 (CB2) receptors in animal models of vagally-mediated behaviors. Injections of dronabinol, a non-selective CB1/CB2 receptor agonist, into the nodose ganglia reduced serotonin (5-HT)-induced reflex apneas. It is unknown what role CB1 and/or CB2 receptors play in reflex apnea. Here, to determine the independent and combined effects of activating CB1 and/or CB2 receptors on dronabinol’s attenuating effect, rats were pre-treated with CB1 (AM251) and/or CB2 (AM630) receptor antagonists. Adult male Sprague-Dawley rats were anesthetized, instrumented with bilateral electrodes to monitor genioglossus electromyogram (EMGgg) and a piezoelectric strain gauge to monitor respiratory pattern. Following intraperitoneal treatment with AM251 and/or AM630, or with vehicle, serotonin was intravenously infused into a femoral vein to induce reflex apnea. After baseline recordings, the nodose ganglia were exposed and 5-HT-induced reflex apneas were again recorded to confirm that the nerves remained functionally intact. Dronabinol was injected into each nodose ganglion and 5-HT infusion was repeated. Prior to dronabinol injection, there were no significant differences in 5-HT-induced reflex apneas or phasic and tonic EMGgg before or after surgery in the CB1, CB2, combined CB1/CB2 antagonist, and vehicle groups. In the vehicle group, dronabinol injections reduced 5-HT-induced reflex apnea duration. In contrast, dronabinol injections into nodose ganglia of the CB1, CB2, and combined CB1/CB2 groups did not attenuate 5-HT-induced reflex apnea duration. However, the CB1 and CB2 antagonists had no effect on dronabinol’s ability to increase phasic EMGgg. These findings underscore the therapeutic potential of dronabinol in the treatment of OSA and implicate participation of both cannabinoid receptors in dronabinol’s apnea suppression effect.
Droperidol enhances fentanyl and sufentanil, but not morphine, analgesia.

Abstract 1. 1. The effect of droperidol pre-treatment on the analgesic potency of morphine, fentanyl and sufentanil was assessed in mice. 2. 2. Acetic acid writhing test and tail immersion test were used to measure the analgesic response. 3. 3. The neuroleptic augments the effects of sufentanil and fentanyl. 4. 4. Thus, the dose-response curves for fentanyl and sufentanil were shifted to the left and the ED50 of the analgesics lowered in droperidol pre-treated animals. 5. 5. However, morphine analgesia was not influenced by droperidol. 6. 6. The results suggest that combination of sufentanil or fentanyl with droperidol may be better than morphine to produce neuroleptanalgesia and anesthesia.
The comparative diet of three Saharan sand dune skinks

Abstract We compared the diets of the only three sand dune skinks of North Sinai, Chalcides ocellatus, Scincus scincus, and Sphenops sepsoides. Despite our small sample size, we found several interesting trends. Coleoptera was the most common prey order eaten by the skinks, occurring in about 90% of the stomachs for each species of lizard. The other prey orders occurred with far lower frequencies. Vegetation and seeds occurred in over half of the stomachs of the diurnal, S. scincus and C. ocellatus. The high occurrence of plant materials in the stomachs of S. scincus and C. ocellatus suggest that these items were intentionally consumed. Vegetation and seeds occurred at a far lower frequency in the nocturnal S. sepsoides, which fits the general pattern of low vegetation consumption by nocturnal and subterranean lizards. An interesting find of this study was an Acanthodactylus longipes in a S. scincus stomach ‐ to our knowledge, this is the first such record. The occurrence of the lizard A. longipes, and hi...
On two questions concerning tilings

We prove that a tiling of the plane by topological disks is locally finite at most boundary points of tiles, confirming a conjecture by Valette. This comes by way of a much more general theorem on tilings of topological vector spaces. We also investigate a question raised by Klee as to whether or not there is a tiling of separable Hilbert space by bounded convex tiles. We present evidence to support the conjecture that the answer is negative.
Patterns in program references

This paper describes a study of sane of the characteristics of program referencing patterns. Program behavior is investigated by constructing stochastic models for the page reference mechanism and evaluating the validity of the assumptions made through comparison with empirical results. The notion of a regime process is shown to play a useful role in describing the observed phenomena mathematically. The study falls within the realm of a rapidly growing field of computer science known as compumetrics, where quantitative and qualitative methods are being applied to the study and evaluation of computer performance.
Maximum likelihood estimation of interclass correlations

SUMMARY The method of maximum likelihood is used to estimate a mother-child correlation, PMS, when there are a variable number of offspring per family. The technique is iterative and uses standard Newton-Raphson procedures to facilitate convergence. A comparison is made using Monte Carlo methods between the maximum likelihood estimator and other more traditional estimators of interclass correlations. It is shown that the maximum likelihood estimator is roughly equivalent in mean squared error to the pairwise estimator. A major goal in the analysis of familial data is to measure for a particular trait the correla- tion between two different types of family member. We call such a correlation an interclass correlation. Several estimators have been proposed for such an interclass correlation in the special case, such as a mother-child correlation, where one type of family member consists of a unique individual. These estimators have been discussed in detail by Rosner, Donner & Hennekens (1977) and include (a) the pair-wise estimator where each child in a family is paired with the mother of that family, (b) the sib-mean estimator where the mean offspring score from a family is paired with the mother of that family, (c) the random sib estimator where a random offspring is chosen from each family and is paired with the mother of that family, and (d) the ensemble estimator, a variant of (c) whereby an 'expected value' for the random sib estimator is computed over all possible choices of random sibs from each family. For estimators (a)-(c), an ordinary Pearson correlation is computed from the set of pairs formed over all families in the sample. It was shown by Rosner et al. (1977) that estimators (a) and (d) are far superior to (b) and (c) in terms of mean squared error with the pairwise
On Predicting Softening Effects in Hard Turned Surfaces—Part II: Finite Element Modeling and Verification

A material softening model based on thermal activation energy has been successfully established through tempering experiments in the first part of this study. To apply the model to predicting material softening in hard turned surfaces, the thermal history of work material is needed. In this part, a three-dimensional finite element (FE) model of machining hardened 52100 steel is constructed, and coupled thermal-stress analysis is performed to obtain the material thermal history. Then the material softening model uses the computed thermal history as input to predict the material hardness profiles along the depth into the machined surfaces. Overall, the prediction precisely catches the trend of hardness change along depth and agrees reasonably well with the hardness measurement. What's more, the sensitivity of material softening to cutting parameters is investigated both quantitatively and qualitatively. Within the investigation range, it is observed that the increase of tool flank wear and feed rate produces severe material softening and a deeper softened layer, while the increase of cutting speed causes significant softening to the surface material but hardly changes the softened depth.
A Characterization of the problem of secure provenance management

Data (or information) provenance has many important applications. However, prior work on data provenance management almost exclusively focused on the collection, representation, query, and storage of provenance data. In contrast, the security aspect of provenance management has not been understood nor adequately addressed. A natural question then is: What would a secure provenance management system - perhaps as an analogy to secure database management systems - look like? In this paper, we explore the problem space of secure provenance management systems with an emphasis on the security requirements for such systems, and characterize desired solutions for tackling the problem. We believe that this paper makes a significant step towards a comprehensive solution to the problem of secure provenance management.
The Doppler sensitivity of large TW phase modulated waveforms

The narrowband approach to coherent processing of large-TW waveforms in Doppler delay multiplies the data stream by the complex conjugate of the undilated envelope and uses FFT processing to test Doppler. This results in a correlation loss that depends fundamentally on the TW product of the waveform envelope and the amount of Doppler-induced time-base dilation occurring in the data. It is shown that it is possible to reduce the number of dilated envelope replicas required to cover a given Doppler band by dividing the band into subbands. Each narrowband is processed using an envelope replica with a fixed dilation parameter, and the width of each band is a function of a specified correlation loss limit, the TW product, and a Doppler sensitivity parameter that depends on the specific time-frequency allocation of the envelope. Examples are provided for envelopes with both continuous and discrete (FSK) allocations with emphasis on the class of unit allocation (UA) codes that includes all full Costas arrays, for which upper and lower bounds for Doppler sensitivity are derived. >
The amorphization of complex silicates by ion-beam irradiation

Twenty-five silicates were irradiated at ambient temperature conditions with 1.5 MeV Kr+. Critical doses of amorphization were monitored in situ with transmission electron microscopy. The doses required for amorphization are compared with the structures, bond-types, compositions, and physical properties of the silicates using simple correlation methods and more complex multivariate statistical analysis. These analyses were made in order to determine which properties most affect the critical amorphization dose. Simple two-variable correlations indicate that melting point, efficiency of atomic packing, the dimensionality of SiO4 polymerization (DOSP), and bond ionicity have a relationship with critical amorphization dose. However, these relationships are evident only in selected portions of the data set; that is, for silicate phases with a common structure type. A clearer relationship between the silicate properties and critical amorphization dose was determined for the entire data set with multiple linear regression. Several regression models are proposed which describe the variation in amorphization dose. All regression models contain the following properties: (i) melting point; (ii) a structural variable (DOSP, elastic modulus, and/or atomic packing); and (iii) the proportion of Si–O bonding (instead of bond ionicity). The regression models are equivalent, because they represent combinations of similar properties. Notably, density and atomic mass are not controlling properties for the critical amorphization dose. Melting and amorphization by ion irradiation are apparently related processes. Neither melting point nor critical amorphization dose can be predicted by considering only the structure, composition, or bonding of a particular phase. The Si–O bond is the most covalent bond in silicates, and is the “weak link” in the structure with respect to amorphization. Thus, DOSP is also an important property, as the topology of these ”weak links” influences a structure’s ability to accumulate amorphous regions. The efficiency of atomic packing is related to the process of defect self-recombination during amorphization. The bulk modulus and shear modulus are important variables within the regression models because of their direct relationship to atomic packing.
Implantable cardioverter-defibrillator lead complication: When is an outbreak out of bounds?

Despite the proven benefit of implantable cardioverterdefibrillators (ICDs) in reducing the risk of sudden death and total mortality in specific high-risk populations, the total annual number of ICD implants has declined. 1 Questions regarding the reliability and performance of ICD systems have dogged the industry, and, as a result, numerous patients at risk for sudden death and candidates for ICD therapy remain untreated. Countless preventable deaths have resulted. Front and center amid the performance concerns have been ICD leads. Although simple in concept, defibrillator leads are complex devices. Given the hundreds of thousands of leads in distribution and the high-performance expectations, concerns about implant complications, malfunctions, reliability, and clinical performance are not only understandable but inevitable. Performance concerns plaguing the St. Jude Medical Riata ICD lead are emblematic of the challenges facing ICD patients, physicians, regulators, and industry. Although reports had already appeared in the medical literature, most patients and physicians became aware of concerns about an increased risk of subacute perforation with the Riata ICD lead on November 12, 2007, when the Wall Street Journal published an article noting that the Riata was “in rare instances puncturing holes in the hearts of cardiac patients” and in some cases “nearly poking through the patients’ skin.” 2 One medical journal report of a single Riata ICD lead perforation was entitled “Delayed Defibrillator Lead Perforation: An Increasing Phenomenon” (italics added for emphasis). 3 How are patients and physicians to respond to
Modeling study of the effects of overlapping Ca2+ microdomains on neurotransmitter release

Although single-channel Ca2+ microdomains are capable of gating neurotransmitter release in some instances, it is likely that in many cases the microdomains from several open channels overlap to activate vesicle fusion. We describe a mathematical model in which transmitter release is gated by single or overlapping Ca2+ microdomains produced by the opening of nearby Ca2+ channels. This model accounts for the presence of a mobile Ca2+ buffer, provided either that the buffer is unsaturable or that it is saturated near an open channel with Ca2+ binding kinetics that are rapid relative to Ca2+ diffusion. We show that the release time course is unaffected by the location of the channels (at least for distances up to 50 nm), but paired-pulse facilitation is greater when the channels are farther from the release sites. We then develop formulas relating the fractional release following selective or random channel blockage to the cooperative relationship between release and the presynaptic Ca2+ current. These formulas are used with the transmitter release model to study the dependence of this form of cooperativity, which we call Ca2+ current cooperativity, on mobile buffers and on the local geometry of Ca2+ channels. We find that Ca2+ current cooperativity increases with the number of channels per release site, but is considerably less than the number of channels, the theoretical upper bound. In the presence of a saturating mobile buffer the Ca2+ current cooperativity is greater, and it increases more rapidly with the number of channels. Finally, Ca2+ current cooperativity is an increasing function of channel distance, particularly in the presence of saturating mobile buffer.
A Case Study of Convective Boundary Layer Development during IHOP_2002: Numerical Simulations Compared to Observations

Abstract Results are presented from a combined numerical and observational study of the convective boundary layer (CBL) diurnal evolution on a day of the International H2O Project (IHOP_2002) experiment that was marked by the passage of a dryline across part of the Oklahoma and Texas Panhandles. The initial numerical setup was based on observational data obtained from IHOP_2002 measurement platforms and supplementary datasets from surrounding locations. The initial goals of the study were as follows: (i) numerical investigation of the structure and evolution of the relatively shallow and homogeneous CBL east of the dryline by means of large-eddy simulation (LES), (ii) evaluation of LES predictions of the sheared CBL growth against lidar observations of the CBL depth evolution, and (iii) comparison of the simulated turbulence structures with those observed by lidar and vertically pointing radar during the CBL evolution. In the process of meeting these goals, complications associated with comparisons betwee...
Some Bayesian lower bounds on reliability in the lognormal distribution

The two-parameter lognormal distribution with density function f(y: γ, σ2) = [(2πσ2)1/2y] 1exp[−(ln y − γ)2/2σ2], y > 0, is important as a failure-time model in life testing. In this paper, Bayesian lower bounds for the reliability function R(t: γ, σ2) = ϕ[(γ − ln t)/σ] are obtained for two cases. First, it is assumed that γ is known and σ2 has either an inverted gamma or “general uniform” prior distribution. Then, for the case that both γ and σ2 are unknown, the normal-gamma prior and Jeffreys' vague prior are considered. Some Monte Carlo simulations are given to indicate some of the properties of the Bayesian lower bounds.
Adapted waveform libraries in magnetic resonance imaging

The authors consider several implementation issues associated with wavelet encoding, an application of wavelet techniques to signal acquisition in magnetic resonance imaging (MRI). A quantitative analysis of the signal-to-noise limitations of this method is presented. It is found that the localized support features of wavelet bases which provide desirable properties of imaging speed and artifact reduction also degrade the signal-to-noise performance. A partial solution, utilizing adapted waveform libraries, is suggested. In many cases, a priori information may be used in the creation of tailored bases. These provide resistance to artifacts only where needed, while encoding other portions of the image with more globally supported waveforms in order to enhance the signal-to-noise performance in these regions. >
Fractured shale-gas systems

The first commercial United States natural gas production (1821) came from an organic-rich Devonian shale in the Appalachian basin. Understanding the geological and geochemical nature of organic shale formations and improving their gas producibility have subsequently been the challenge of millions of dollars worth of research since the 1970s. Shale-gas systems essentially are continuous-type biogenic (predominant), thermogenic, or combined biogenic-thermogenic gas accumulations characterized by widespread gas saturation, subtle trapping mechanisms, seals of variable lithology, and relatively short hydrocarbon migration distances. Shale gas may be stored as free gas in natural fractures and intergranular porosity, as gas sorbed onto kerogen and clay-particle surfaces, or as gas dissolved in kerogen and bitumen. Five United States shale formations that presently produce gas commercially exhibit an unexpectedly wide variation in the values of five key parameters: thermal maturity (expressed as vitrinite reflectance), sorbed-gas fraction, reservoir thickness, total organic carbon content, and volume of gas in place. The degree of natural fracture development in an otherwise low-matrix-permeability shale reservoir is a controlling factor in gas producibility. To date, unstimulated commercial production has been achievable in only a small proportion of shale wells, those that intercept natural fracture networks. In most other cases, a successful shale-gas well requires hydraulic stimulation. Together, the Devonian Antrim Shale of the Michigan basin and Devonian Ohio Shale of the Appalachian basin accounted for about 84% of the total 380 bcf of shale gas produced in 1999. However, annual gas production is steadily increasing from three other major organic shale formations that subsequently have been explored and developed: the Devonian New Albany Shale in the Illinois basin, the Mississippian Barnett Shale in the Fort Worth basin, and the Cretaceous Lewis Shale in the San Juan basin. In the basins for which estimates have been made, shale-gas resources are substantial, with in-place volumes of 497‐783 tcf. The estimated technically recoverable resource (exclusive of the Lewis Shale) ranges from 31 to 76 tcf. In both cases, the Ohio Shale accounts for the largest share.
Length control of the metaphase spindle

Summary Background The pole-to-pole distance of the metaphase spindle is reasonably constant in a given cell type; in the case of vertebrate female oocytes, this steady-state length can be maintained for substantial lengths of time, during which time microtubules remain highly dynamic. Although a number of molecular perturbations have been shown to influence spindle length, a global understanding of the factors that determine metaphase spindle length has not been achieved. Results Using the Drosophila S2 cell line, we depleted or overexpressed proteins that either generate sliding forces between spindle microtubules (Kinesin-5, Kinesin-14, dynein), promote microtubule polymerization (EB1, Mast/Orbit [CLASP], Minispindles [Dis1/XMAP215/TOG]) or depolymerization (Kinesin-8, Kinesin-13), or mediate sister-chromatid cohesion (Rad21) in order to explore how these forces influence spindle length. Using high-throughput automated microscopy and semiautomated image analyses of >4000 spindles, we found a reduction in spindle size after RNAi of microtubule-polymerizing factors or overexpression of Kinesin-8, whereas longer spindles resulted from the knockdown of Rad21, Kinesin-8, or Kinesin-13. In contrast, and differing from previous reports, bipolar spindle length is relatively insensitive to increases in motor-generated sliding forces. However, an ultrasensitive monopolar-to-bipolar transition in spindle architecture was observed at a critical concentration of the Kinesin-5 sliding motor. These observations could be explained by a quantitative model that proposes a coupling between microtubule depolymerization rates and microtubule sliding forces. Conclusions By integrating extensive RNAi with high-throughput image-processing methodology and mathematical modeling, we reach to a conclusion that metaphase spindle length is sensitive to alterations in microtubule dynamics and sister-chromatid cohesion, but robust against alterations of microtubule sliding force.
Characterization of bulk defect response in Cu(In, Ga)Se 2 thin-film solar cell using DLTS

Deep level transient spectroscopy has been used to study the spatial properties of the N1-admittance feature in Cu(In, Ga)Se2 devices. By comparison to admittance spectra, the N1-admittance feature has been identified in deep level transient spectra. By varying the filling pulse voltage used to generate the deep level transient spectra, the spatial properties of the N1-admittance feature are determined. In particular, the N1-admittance feature is shown to arise from a uniformly distributed bulk defect in the sample studied.
Delayed demand information and dampened bullwhip effect

This paper considers an inventory setting in which the historical data used for demand forecasting is delayed. When the replenishment is controlled via an order-up-to policy, we show that such delays reduce the variability of the order history and dampen the bullwhip effect. We discuss the intuition behind this result.
Why Humans Are Unique: Three Theories.

Three recent papers reject Darwin's claim that there is no fundamental difference between humans and animals. Each offers a unique theory of the difference. The first theory holds that although ani...
Absorptive Capacity in R&D Project Teams: A Conceptualization and Empirical Test

The purpose of this study is to answer a call for the rejuvenation of the absorptive capacity (ACAP) construct by offering a novel conceptualization and empirical test of a multidimensional model of R&D project team ACAP that portrays it as a capability distinct from prior knowledge, specifies each dimension's level of analysis, distinguishes between individual and collective assimilation, and considers the moderating effects of team structure. Using a dataset from survey and archival sources on 100 innovations by R&D project teams, we find that the capability of R&D team members to evaluate external knowledge is related to their ability to assimilate it and that both individual assimilation capabilities and collective assimilation capabilities, in the form of ability to reach a shared understanding, are important to the team's ability to apply external knowledge. We also find that prior knowledge negatively moderates the relationship between individual assimilation and application ability and that team autonomy positively moderates this relationship. By clarifying levels of analysis and encompassing multiple dimensions of ACAP, this work leads to a more fine-grained understanding of the complex nature of ACAP. Implications of these findings for future research and R&D team management are presented.
Flow stress of commercially pure niobium over a broad range of temperatures and strain rates

The thermomechanical response of a commercially pure niobium (CP niobium) is investigated systematically in quasi-static (Instron, servohydraulic) and dynamic (UCSD’s recovery Hopkinson) compression. Strains over 70% are achieved in these tests over a temperature range of 77‐800 K and strain rates of 10 3 to 8000 s 1 . At the macroscopic level, the flow stress of CP niobium, within the plastic deformation regime, is dependent strongly on the temperature and strain rate. At temperatures below 296 K (room temperature), the flow stress of CP niobium at quasi-static strain rates is more sensitive to the temperature than it is at high strain rates. Dynamic strain aging occurs at 400 K at quasi-static strain rates. The microstructure of the deformed samples shows that adiabatic shearbands occur at low temperatures and high strain rates. Deformation twins are seen outside these shearbands. Results of the temperature- and strain-rate-jump tests show that, the corresponding microstructural changes are not significant. Finally, based on the concept of dislocation kinetics, paralleled with the systematic experimental investigation, a model describing the flow stress of CP niobium under high strain rates is developed by combining the effects of the long-range barriers to the motion of dislocations, with those of the short-range temperature- and strain rate-dependent barriers. The predicted flow stress and the experimental results are compared, attaining good agreement. © 2000 Elsevier Science S.A. All rights reserved.
Knee and hip articular cartilage have distinct epigenomic landscapes: implications for future cartilage regeneration approaches

Objectives To elucidate the functional epigenomic landscape of articular cartilage in osteoarthritis (OA) affected knee and hip joints in relation to gene expression. Methods Using Illumina Infinium HumanMethylation450 BeadChip arrays, genome-wide DNA methylation was measured in 31 preserved and lesioned cartilage sample pairs (14 knees and 17 hips) from patients who underwent a total joint replacement due to primary OA. Using previously published genome-wide expression data of 33 pairs of cartilage samples, of which 13 pairs were overlapping with the current methylation dataset, we assessed gene expression differences in differentially methylated regions (DMRs). Results Principal component analysis of the methylation data revealed distinct clustering of knee and hip samples, irrespective of OA pathophysiology. A total of 6272 CpG dinucleotides were differentially methylated between the two joints, comprising a total of 357 DMRs containing 1817 CpGs and 245 unique genes. Enrichment analysis of genes proximal of the DMRs revealed significant enrichment for developmental pathways and homeobox (HOX) genes. Subsequent transcriptomic analysis of DMR genes exposed distinct knee and hip expression patterns. Conclusions Our findings reveal consistent DMRs between knee and hip articular cartilage that marked transcriptomic differences among HOX genes, which were not reflecting the temporal sequential HOX expression pattern during development. This implies distinct mechanisms for maintaining cartilage integrity in adulthood, thereby contributing to our understanding of cartilage homeostasis and future tissue regeneration approaches.