cssi/SciSciGPT-SciSciNet huggingface dataset:
Large-Scale Portfolio Optimization

This paper describes a practical algorithm for large-scale mean-variance portfolio optimization. The emphasis is on developing an efficient computational approach applicable to the broad range of portfolio models employed by the investment community. What distinguishes these from the "usual" quadratic program is i the form of the covariance matrix arising from the use of factor and scenario models of return, and ii the inclusion of transactions limits and costs. A third aspect is the question of whether the problem should be solved parametrically in the risk-reward trade off parameter, λ, or separately for several discrete values of λ. We show how the parametric algorithm can be made extremely efficient by "sparsifying" the covariance matrix with the introduction of a few additional variables and constraints, and by treating the transaction cost schedule as an essentially nonlinear nondifferentiable function. Then we show how these two seemingly unrelated approaches can be combined to yield good approximate solutions when minimum trading size restrictions "buy or sell at least a certain amount, or not at all" are added. In combination, these approaches make possible the parametric solution of problems on a scale not heretofore possible on computers where CPU time and storage are the constraining factors.
Hepatitis B vaccine for health care personnel

The hepatitis B vaccine (HB-Vax”), manufactured by Merck Sharp and Dohme from the plasma of high titre HBsAg carriers, became available in the United Kingdom in September 1982. The vaccine containing purified hepatitis B surface antigen (HBsAg) has been shown to induce antibodies to this antigen (anti-HBs) in at least 90 per cent of healthy recipients completing a course of three immunizations over a 6-month period (Szmuness et al., 1980; Szmuness et al., 1981). The development of anti-HBs has correlated with protection from infection resulting in a highly significant reduction in the incidence of hepatitis B in the immunized groups with complete protection being demonstrated for those who developed vaccineinduced anti-HBs prior to exposure (Szmuness et al., 1980). To date, the vaccine has been shown to be safe with no evidence of transmission of hepatitis B or non-A, non-B hepatitis. The only side effect of note in placebo-controlled trials has been a local reaction at the site of injection. Concern has been expressed as to the possibility of adventitious infective agents, primarily viruses, being present in the vaccine. The hepatitis B carriers used as a source of plasma for preparation of the vaccine may well belong to groups in whom the acquired immunodeficiency syndrome (AIDS) occurs. Several features of this severe, life-threatening syndrome, particularly the epidemiology, suggest the possibility of an infective agent. However, the preparation of the vaccine involves procedures, such as ultracentrifugational purification and treatment with formalin and 8 M urea, which are said to effectively remove or inactivate representatives of all known groups of animal viruses, including slow viruses and retroviruses. In September 1982 (Morbidity and Mortality Weekly Report, 19823) it was reported that no cases of AIDS had been diagnosed in the first 19,000 recipients of the vaccine despite its use in populations known to be at risk. However, a more recent report indicates that AIDS has occurred in vaccine recipients but the incidence is certainly no more than in a similar unimmunized group (American Association of Blood Banks, 1983). In a homosexual population AIDS has been diagnosed in two of approximately 1800 immunized, whereas 45 cases occurred in 10,300 of an unimmunized group. Each batch of vaccine is safety tested by inoculation into chimpanzees. Although primates have been shown to develop a syndrome closely resembling AIDS (Henrickson et al., 1983) there are no reports of human
Second-harmonic generation based on quasi-phase matching: a novel configuration.

We consider the possibility of generating second-harmonic radiation by the interaction of two counter-propagating fundamental waves in a quasi-phase-matched second-order nonlinear medium in a waveguide. The conversion efficiency reaches a maximum at an optimum pump intensity. For a large range of pump intensities below a certain pump intensity the efficiency is larger than that for the copropagating configuration. The saturation intensities at which the efficiency reaches 72% for poled KTiOPO4 and LiNbO3 can be achieved with lasers now available.
Computed and experimental surface pressure and heating on 70-deg sphere cones

A comparison of computed and experimental surface pressure and heating on 70-deg sphere cones at angles of attack up to 20 deg is presented. The sphere cone geometries were varied by changing the bluntness ratio and corner radius of the configuration. A three-dimensional Euler flowfield solution yielded surface pressures and was coupled with an axisymmetric analogue technique to determine surface heating. These computational results have then been compared with available experimental data.
A Linearized Intensity Modulator for Photonic Analog-to-Digital Conversion Using an Injection-Locked Mode-Locked Laser

A linearized intensity modulator for pulsed light based on an injection-locked mode-locked laser (MLL) is presented here. This has been realized by introducing a monolithic Fabry–Perot MLL into one of the arms of a conventional Mach–Zehnder interferometer (MZI) and injection-locking it to a MLL which is the input to the interferometer. By modulating the current on the gain section or the voltage of the saturable absorber (SA) section of the injection-locked laser, one can introduce an arcsine phase response on each of the injected longitudinal modes. By combining the modulated optical comb with its unmodulated counterpart one can produce a linearized intensity modulator. The linearity of this modulator is inherent in its design and no pre- or postdistortion linearization scheme is utilized. The results of the two-tone intermodulation experiment are presented here for this modulator and a spur-free dynamic range (SFDR) of ∼70 dB·Hz2/3 is achieved by modulating the voltage of the SA. The reported SFDR is limited by the noise of the MLLs. The dynamic range could be further improved by decoupling the phase modulation and amplitude modulation. The proposed and demonstrated configuration as an analog optical link with improved linearity has the potential to increase the performance and resolution of photonic analog-to-digital converters (ADCs).
Summer tree roost selection by Rafinesque's big-eared bat

Roost requirements of most North American forest bats are well-documented, but questions remain regarding the ultimate mechanisms underlying roost selection. Hypotheses regarding roost selection include provision of a stable microclimate, space for large colonies, protection from predators, and proximity to foraging habitat, among others. Although several hypotheses have been proposed, specific mechanisms likely vary by species and geographic region. Rafinesque's big-eared bat (Corynorhinus rafinesquii) commonly roosts in trees with large basal hollows in the Coastal Plain of the southeastern United States. Our objective was to weigh evidence for hypotheses regarding selection of diurnal summer roosts by Rafinesque's big-eared bat at 8 study sites across the Coastal Plain of Georgia, USA. We used transect searches and radiotelemetry to locate roosts and measured 22 characteristics of trees, tree cavities, and surrounding vegetation at all occupied roosts and for randomly selected unoccupied trees. We evaluated 10 hypotheses using single-season occupancy models and used Akaike's information criterion to select the most parsimonious models. We located 170 tree roosts containing approximately 870 bats for our analysis. The best supported model predicted bat presence from cavity size, interior wall texture, and number of entrances. Because large cavities allow bats to fly and smooth walls impede attacks by terrestrial predators, our results are consistent with the hypothesis that bats select roosts that allow them to evade predators. However, data on predation rates are needed for a conclusive determination. Because trees suitable as roosts for Rafinesque's big-eared bat are rare in the landscape, protection of suitable forested wetland habitat is essential to provide current and long-term roost tree availability. © 2012 The Wildlife Society.
Influence of food-simulating solvents on resin composites and glass-ionomer restorative cement

Abstract The specific aim of the study was to determine the effect that food-simulating solvents have on varyingly constituted resin composites and glass ionomer. Samples were stored in food-simulating liquids (FSL) (in increasing order of solubility parameter): Heptane, 100%, 75%, 50%, 25%, and 0% aqueous ethanol solutions for 0, 1, 3, 7, 18, and 30 days at 37°C prior to Knoop Hardness measurements. Measurements were made on both the unpolished matrix-rich surface and the polished filler-rich surface. Multifactorial analysis of variance revealed significant differences in hardness among materials, surface finish, solution, storage time, and all of their interactions. The average hardness of the polished surface was higher than that of the unpolished surface. Resin composites with similar matrix chemistry tended to behave similarly in FSL. Those with Urethane DMA matrix were found to be significantly more susceptible to FSL than were those with the BisGMA matrix. Glass ionomer behaved differently in FSL compared with composites, due to differences in matrix chemistry, the nature of the bond between filler and matrix, and its susceptibility to dehydration.
Lupus Susceptibility Genes on Human Chromosome 1

During the past five years, there has been an intense interest in studying candidate susceptibility genes for systemic lupus erythematosus (SLE). Many such studies have been focused on candidates located on chromosome 1, demonstrating association of certain genetic variants with SLE. Some of the tested candidate genes were chosen because they encode molecules with relevant immunological functions that may play a role in the pathogenesis of SLE. More recently, the identification of genomic segments linked to SLE has suggested novel positional candidate genes. Thus far, there is considerable evidence supporting that multiple genes on this chromosome contribute to the development and expression of SLE. This review highlights the genetic loci located on chromosome 1 that have recently been associated with SLE. These include loci encoding the tumor necrosis factor receptor 2 (TNFR2), complement component C1q, Fcgamma receptors, T cell receptor zeta chain, interleukin-10 (IL-10), poly (ADP-ribose) polymerase (PARP), and HRES-1.
Myofibroblasts: Trust your heart and let fate decide

Cardiac fibrosis is a substantial problem in managing multiple forms of heart disease. Fibrosis results from an unrestrained tissue repair process orchestrated predominantly by the myofibroblast. These are highly specialized cells characterized by their ability to secrete extracellular matrix (ECM) components and remodel tissue due to their contractile properties. This contractile activity of the myofibroblast is ascribed, in part, to the expression of smooth muscle α-actin (αSMA) and other tension-associated structural genes. Myofibroblasts are a newly generated cell type derived largely from residing mesenchymal cells in response to both mechanical and neurohumoral stimuli. Several cytokines, chemokines, and growth factors are induced in the injured heart, and in conjunction with elevated wall tension, specific signaling pathways and downstream effectors are mobilized to initiate myofibroblast differentiation. Here we will review the cell fates that contribute to the myofibroblast as well as nodal molecular signaling effectors that promote their differentiation and activity. We will discuss canonical versus non-canonical transforming growth factor-β (TGFβ), angiotensin II (AngII), endothelin-1 (ET-1), serum response factor (SRF), transient receptor potential (TRP) channels, mitogen-activated protein kinases (MAPKs) and mechanical signaling pathways that are required for myofibroblast transformation and fibrotic disease. This article is part of a Special Issue entitled "Myocyte-Fibroblast Signalling in Myocardium ".
Comprehensive comparison of nucleidic mass formulae based on different nuclear models

Abstract The following quantities have been calculated with the nucleidic masses of the semi- empirical formulae recently developed by Kummel et al. , Seeger, Zeldes et al. , and Garvey and Kelson: (i) alpha decay energies as a function of neutron number N ; (ii) slopes and intercepts of isotone lines representing neutron-pair separation energies as a function of proton number Z ; (iii) roughness parameter, defined as E β ( Z , N + 1) + E β ( Z −1, N )− E ββ ( Z −1, N +1), where E β and E ββ are total and double β − decay energies, respectively; (iv) steepness, minima, and separation distances of isobaric parabolas; and (v) energies available for emission of delayed neutron and delayed proton from precursors. These calculated quantities show systematic and random deviations from the empirical data at various mass regions. The present comparison easily reveals the similarities and differences among the nucleidic mass formulae which are based on various nuclear models. A list of errors in the publication by Kummel et al. on their mass equation is included.
Massively Parallel Mathematical Sieves

The Sieve of Eratosthenes is a well-known algorithm for finding all prime numbers in a given subset of integers. A parallel version of the Sieve is described that produces computational speedups over 800 on a hypercube with 1,024 processing elements for problems of fixed size. Computational speedups as high as 980 are achieved when the problem size per processor is fixed. The method of parallelization generalizes to other sieves and will be efficient on any ensemble architecture. We in vestigate two highly parallel sieves using scattered de composition and compare their performance on a hyper cube multiprocessor. A comparison of different paralleli zation techniques for the sieve illustrates the trade-offs necessary in the design and implementation of mas sively parallel algorithms for large ensemble computers.
Antizyme inhibitor: mysterious modulator of cell proliferation

In contrast to the considerable interest in the oncogene ornithine decarboxylase (ODC) and in the family of antizymes with regard to cell proliferation and tumorigenesis, the endogenous antizyme inhibitor (AZI) has been less well studied. AZI is highly homologous to the enzyme ODC but does not possess any decarboxylase activity. Elevated ODC activity is associated with most forms of human malignancies. Antizymes bind ODC, inhibit ODC activity and promote the ubiquitin-independent degradation of ODC. Consequently they are proposed as tumor suppressors. In particular, the most studied member of the antizyme family, antizyme 1, has been demonstrated to play a role in tumor suppression. AZI inactivates all members of the antizyme family, reactivates ODC and prevents the proteolytic degradation of ODC, which may suggest a role for AZI in tumor progression.
How do you fake a personality test? An investigation of cognitive models of impression-managed responding

Abstract Because faking poses a threat to the validity of personality measures, research has focused on ways of detecting faking, including the use of response times. However, the applicability and validity of these approaches are dependent upon the actual cognitive process underlying faking. This study tested three competing cognitive models in order to identify the process underlying faking and to determine whether response time patterns are a viable method of detecting faking. Specifically, we used a within-subjects manipulation of instructions (respond honestly, make a good impression, make a specific impression) to examine whether the distribution of response times across response scale options (e.g., disagree, agree) could be used to identify faking on the NEO PI-R. Our results suggest that individuals reference a schema of an ideal respondent when faking. As a result, response time patterns such as the well-known inverted-U cannot be used to identify faking.
Relationship between nonverbal sensitivity, encoding, and relational satisfaction

This study examined the relationship between individuals’ social skills, their partners’ assessments of their social skills, and both parties’ relationship satisfaction. Participants (N = 112) completed the Interpersonal Perception Task, the emotional expressivity and social expressivity subscales of the Social Skills Inventory, the Conversational Skills Ratings scale, and the Relationship Assessment Scale. Partners completed the Conversational Skills Ratings scale on participants, and the Relationship Assessment Scale. Regression equations were performed using participant and partner satisfaction as the dependent variables and participant social skills as the independent variables. Results revealed that partner assessment of participant conversational skill predicted partner satisfaction.
Nitrogen excretion of Crassostrea virginica

Abstract 1. Water in which groups of 6 oyster, Crassostrea virginica , had been held for 24 hr was analyazzed by standards methods for nitrogenous excretion products. 2. Results of the most complete analysis, expressed as μmoles ammonia/100g oyster/day, were: ammonia 12·50, urea 2·2.54, amino acids 1·01, unidentified 3·20, total 19·25.
A neural approach to concept representation suggests explanations for certain aspects of aphasia, alexia, and agraphia

Abstract Slightly more than 10,000 constraints on permissible connection values within a relatively simple nerve network are discussed and shown to enable modeling of certain aspects of concept representation and production of semantic errors associated with injury-related aphasia, agraphia, and alexia. The constraints considered include those that must be satisfied for novel and familiar examples of familiar categories to be appropriately named, for groups containing members of several categories to be named, for members of each category to be listed, for information to be correctly transferred from one concept to another, and for the severity of errors to be minimized when inappropriate names are selected. The model is startling because it involves only six learning rules that guide adjustment of connection strengths to values which generally satisfy the 10,000 constraints, and because network connections are so strictly regulated—with several hundred constraints simultaneously limiting the range of values permitted for each connection—that it seems reasonable to ask whether any qualitatively different explanations for these aspects of concept representation are possible. This study describes a simulation rather than a mathematical model. Its inclusion in a journal of mathematical modeling is intended to spur the interest of mathematicians. so that an appropriate mathematical analysis can be conducted.
Optimal receiver bandwidth for energy-detection PPM UWB systems

Non-coherent UWB receivers are often implemented using energy detection architectures which are very sensitive to noise in the channel and interference. Therefore, the receiver bandwidth plays an important role since the total noise and interference energy is proportional to this bandwidth. This work provides analytical expressions to find the optimal receiver bandwidth and quantifying the effect on the bit-error-rate (BER) due to channel noise and adjacent-channel interference (ACI). A reduction in receiver bandwidth beyond the optimal point is shown to have minimal impact on BER performance when ACI is negligible.
An improved analytical model for collector currents in lateral bipolar transistors

Detailed analyses of the lateral bipolar transistor have been performed and a physically based model for the collector current developed. Hybrid mode operation of the lateral BJT in the presence of a gate electrode has been considered. Two-dimensional current flow in the base has also been taken into account without the use of empirical parameters. Comparisons with numerical simulations, existing models, and experimental data have been performed to demonstrate the accuracy and improvements realized by the new model. >
The (non)impact of revenue decentralization on fiscal deficits: some evidence from OECD countries†

Recent studies examining the relation between fiscal decentralization and consolidated government fiscal balances generally have not taken proper account of the extent of the independent taxing powers available to sub-national governments and thus have overstated the degree of effective revenue decentralization. Results from a panel regression study of 19 OECD member countries suggest that when the measure of fiscal decentralization is limited to the revenues over which sub-national governments have full autonomy, its impact on fiscal balances is not statistically significant. Accordingly, when accurately measured revenue decentralization appears to have had no negative impact on fiscal discipline.
Endodontic treatment outcome: effect of the permanent restoration

Objective. To investigate the relationship between the presence of the coronal restoration and endodontic treatment success or failure. Methods. This study comprised 200 endodontically treated teeth with 441 roots. Follow-up examination was conducted 4 0.5 years after completion of endodontic treatment. Outcome criteria were modified from Strindberg. Results. Teeth/roots restored with permanent coronal restoration (casting or filling) had a higher success rate (80%) than teeth/roots not restored (60%; P .01) in the analysis of aggregate data. However, the results of stratified analysis on key confounding factor (preoperative periapical diagnosis) showed that there is no significant association between the presence of permanent restoration and endodontic outcome. Teeth with preoperative apical periodontitis were less likely to be restored with a crown (23.9%) than teeth without apical periodontitis (76.1%; P .01). Anterior teeth were more likely to be restored with a filling and sooner than the posterior teeth. These associations suggest a treatment selection bias. Conclusions. Stratified analysis on the key confounding factor reveals that endodontic outcome is driven by the presence of preoperative root canal infection (apical periodontitis). Lack of stratification on key confounding factors inaccurately suggests that presence of permanent restoration contributes to the success of endodontic treatment in the aggregate analysis of grouped data. The choice to restore the tooth as well as the choice and timing of permanent restoration may be the result of a bias in treatment selection. Stratified analysis on key confoundidng factors is the key to valid analysis and accurate results. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:576-82) Eradication of microorganisms from an infected root canal system has been demonstrated in numerous studies to be the key to successful endodontic treatment. Endodontic treatment is therefore focused on asepsis and disinfection with preservation of the remaining tooth structure. Conventional clinical practice assumes that endodontically treated teeth are restored to form and function after the completion of endodontic therapy. It is believed that the presence of coronal restoration helps to protect the endodontically treated tooth and root canal system from coronal leakage and reinfection. It is furthermore often assumed that the protective effect is enhanced if the coronal restoration is placed soon after the completion of endodontic treatment. Numerous studies have suggested that unprotected tooth and root canal structures are vulnerable to reinfection. 1-6 Coronal leakage studies generally demonstrated extensive leakage in experimental models in vitro and in vivo. 7
1997 American Urological Association Gallup survey: Changes in diagnosis and management of prostate cancer and benign prostatic hyperplasia, and other practice trends from 1994 to 1997

AbstractPurpose: The American Urological Association first commissioned the Gallup Organization [sup *] to conduct a study to assess urologist practice patterns in 1992. We present the results of the 1997 survey, the sixth consecutive Gallup survey performed for the Association.Materials and Methods: A random sample of 502 American urologists who had completed urological residency and practiced at least 20 hours weekly in 1996 was interviewed by telephone in February and March 1997.Results: Emerging trends showed significant changes since 1994 in how urologists diagnosed and treated prostate cancer. The survey revealed a significant change in the tests routinely ordered to stage newly diagnosed prostate cancer and for diagnostic evaluation of patients with benign prostatic hyperplasia.Conclusions: Urologists are becoming more cost conscious and effective in ordering pretreatment testing. Urologists are becoming more oriented toward medical treatment for the management of benign prostatic hyperplasia, and ...
Ectopic ureteroceles in duplex systems: Long-term follow up and ‘treatment-free’ status

Abstract Objective Definitive treatment of ectopic ureterocele (EU) implies that no further surgery or prophylactic antibiotic is needed. The literature is unclear on which interventions render a child ‘treatment free’. Materials and methods Thirty (23 female, seven male) patients presented between 1984 and 2000. Follow up ranged from 5 to 15 years (mean: 7). Presenting reasons were: urinary tract infection in 18 (16 females, two males; age: 17 Results Treatment was as follows. No intervention, three (10%). Single procedure, eight (27%): five hemi-nephrectomy (HN), two transurethral incisions (TUI), one excision and re-implantation (ER second procedure 13 ER second 3 TUI; third 2 ER second 1 HN, 1 TUI; third 2 TUI; fourth 2 E&R. Eight (27%) remained on prophylaxis: two had no intervention, in 4 the ectopic ureterocele was in situ after HN or TUI, and two had reflux after E&R. Twenty two (73%) came off prophylaxis (16 E&R, 4 HN, 1 TUI, 1 observation). Poorly or non-functioning upper pole moieties were left in place in 14/18 who underwent E&R. Conclusion ‘Treatment-free’ status most often requires ureterocele excision. HN alone can be definitive, while TUI alone is so rarely. Poor or non-functioning upper pole segments can remain after E&R. Children with collapsed ureteroceles in situ often must remain on antibiotic prophylaxis. A staged approach with initial TUI, followed by E&R, was successful in definitively treating the majority.
Use of Tissue Culture—Amplified Human Immunodeficiency Virus Type 1 to Study Evolutionary Changes In Vivo

To the Editor—We would like to comment on the recent report by Dykes et al. [1] regarding the evolution of the human immunodeficiency virus (HIV) type 1 env gene after treatment with nonnucleoside reverse-transcriptase inhibitors (NNRTIs) and to provide a note of caution regarding the use of tissue culture‐amplified HIV-1 to study short-term viral evolution in vivo. Determining the effect of drug-resistance selection on the evolution of a linked gene, such as env, can provide information regarding the effective population size of HIV-1 in vivo and its potential compartmentalization into anatomical sites where antiviral drug activity may vary [2, 3]. Dykes et al. [1] found no significant correlation between NNRTI therapy and changes in env sequence variants using DNA heteroduplex tracking assays and therefore concluded that these treatments had little impact on HIV-1 env evolution. We offer 5 possible explanations for why their conclusion differs from those of previous studies showing significant changes in envelope gene quasi species during the early phase of virus load rebound after failed protease inhibitor monotherapies [3‐5].
Current Methods for Evaluating Children's Exposures for Use in Health Risk Assessment

Despite the relatively long history of incorporating child-specific safety or exposure factors into U.S. health risk assessments, there has been a growing perception that past scientific and regulatory approaches were not sufficiently protective of infants and children. To address these concerns, a wide range of activities have occurred over the last few years that will likely generate new information on child-specific issues and identify data gaps in current knowledge about children's exposures and health risks. For example, the new publication by the Centers for Disease Control and Prevention, National Report on Human Exposure to Environmental Chemicals, will provide unique information on environmental chemical exposures in the U.S. population using biomonitoring (i.e., blood and urine) analyses. Although preliminary reviews have attempted to summarize what is known about the factors that influence children's exposure and sensitivity to environmental contaminants, there does not appear to be a comprehen...
The paradox of the neutrophilˈs role in tissue injury

The neutrophil is an essential component of the innate immune system, and its function is vital to human life. Its production increases in response to virtually all forms of inflammation, and subsequently, it can accumulate in blood and tissue to varying degrees. Although its participation in the inflammatory response is often salutary by nature of its normal interaction with vascular endothelium and its capability to enter tissues and respond to chemotactic gradients and to phagocytize and kill microrganisms, it can contribute to processes that impair vascular integrity and blood flow. The mechanisms that the neutrophil uses to kill microorganisms also have the potential to injure normal tissue under special circumstances. Its paradoxical role in the pathophysiology of disease is particularly, but not exclusively, notable in seven circumstances: 1) diabetic retinopathy, 2) sickle cell disease, 3) TRALI, 4) ARDS, 5) renal microvasculopathy, 6) stroke, and 7) acute coronary artery syndrome. The activated neutrophil's capability to become adhesive to endothelium, to generate highly ROS, and to secrete proteases gives it the potential to induce local vascular and tissue injury. In this review, we summarize the evidence for its role as a mediator of tissue injury in these seven conditions, making it or its products potential therapeutic targets.
A predictive MD-Nernst–Planck model for transport in alpha-hemolysin: Modeling anisotropic ion currents

A multiscale simulation approach, combining molecular dynamics (MD) and Poisson–Nernst–Planck (PNP) models is used to predict voltage-driven KCl current flow through an a-hemolysin channel. I–V characteristics are calculated for salt concentrations ranging from 50 mM to 3 M. The results show that the fixed charge distribution in the pore walls acts like a macrodipole and introduces a diffusion current component that is responsible for the well-established anisotropic current response. We show that for KCl concentrations in the biological range (50–100 mM), where the Debye length is calculated to be � 4A ˚ , ion currents are dominated by the diffusion component. Conversely, for KCl concentrations in excess of 1 M ion currents approach an isotropic, surface chemistry invariant limit. We calculate 0.1 M I–V characteristics for a range of protein dielectric constant ep and show that ep � 21, is appropriate to account for protein relaxation and self-energy polarization contributions, and is necessary to avoid overestimating the ion current. We show that a generalize form of the Goldman–Hodgkin–Katz (GHK) current equation, using the calculated channel voltage profile captures the current rectifying nature of the a-hemolysin channel. Published by Elsevier B.V.
A synthetic silencer mediates SIR-dependent functions in Saccharomyces cerevisiae.

Abstract Copies of the mating-type genes are present at three loci on chromosome III of the yeast Saccharomyces cerevisiae. The genes at the MAT locus are transcribed, whereas the identical genes at the silent loci, HML and HMR, are not transcribed. Several genes, including the four SIR genes, and two sites, HMR-E and HMR-I, are required for repression of transcription at the HMR locus. Three elements have been implicated in the function of the HMR-E silencer: a binding site for the RAP1 protein, a binding site for the ABF1 protein, and an 11-bp consensus sequence common to nearly all autonomously replicating sequence (ARS) elements (putative origins of DNA replication). RAP1 and ABF1 binding sites of different sequence than those found at HMR-E were joined with an 11-bp ARS consensus sequence to form a synthetic silencer. The synthetic silencer was able to repress transcription of the HMRa1 gene, confirming that binding sites for RAP1 and ABF1 and the 11-bp ARS consensus sequence were the functional components of the silencer in vivo. Mutations in the ABF1 binding site or in the ARS consensus sequence of the synthetic silencer caused nearly complete derepression of transcription at HMR. The ARS consensus sequence mutation also eliminated the ARS activity of the synthetic silencer. These data suggested that replication initiation at the HMR-E silencer was required for establishment of the repressed state at the HMR locus.
Enhancing one life rather than living two: Playing MMOs with offline friends

We use ethnographic, interview, and survey data to examine problematic play within the popular online game, World of Warcraft, or 'WoW' for short. Research shows that players drawn to the interpersonal dimensions of online games are more prone to experience negative outcomes associated with their computer use. Our study suggests that it is not only whether online gamers seek meaningful social interactions that determine if WoW play becomes problematic, but exactly how players interact with others in online game-worlds. Specifically, levels of problematic WoW play depend on the extent gamers play with offline or 'real-life' friends and relations. Our survey data reveals both a direct relationship between playing WoW with offline friends and problematic online gaming and also an indirect one mediated by 'immersion' (defined as the extent that players feel like they are in a virtual world and in some cases actually their character). Interpreting these results through ethnographic and interview data, we suggest that playing WoW with real-life-friends allows gamers to transfer in-game accomplishments and experiences into offline social networks. Rather than competing and conflicting with the world outside of the game, WoW played in this way tends to enhance gamers' offline lives. Further, by keeping gamers in touch with perspectives outside of WoW, playing with real-life-friends instills critical distance and greater awareness of how excessive play can damage offline commitments and relationships, allowing gamers to better monitor, evaluate, and ultimately regulate excessive game-play.
Determination of nonlinear properties of thermal sprayed ceramic coatings via inverse analysis

Abstract A robust procedure to estimate nonlinear mechanical properties of thermally sprayed (TS) ceramic coatings is introduced. Such a method is valuable particularly for TS coatings since each may possess unique properties depending upon its processing condition. Traditionally, their responses have been assumed as linear elastic (isotropic or anisotropic) except in very high temperature environments where softening may occur. However, recent inspections revealed their properties to be more accurately characterized as nonlinear elastic. It appears their distinctive morphology consisting of cracks and interfaces are responsible for such a response. In this work, a versatile procedure to identify nonlinear properties of thermally sprayed coatings is developed. First, a suitable stress–strain model is proposed and then a nonlinear bi-material beam solution is derived. Afterward, an inverse analysis technique is utilized to process the measured curvature–temperature to extract the unknown parameters. Prior to implementing in actual specimens, a detailed simulation study is performed to verify the method’s accuracy as well as robustness. This computational analysis closely replicates deposition processes of TS coatings. With the successful verification, actual curvature measurement of TS yttria-stabilized zirconia (YSZ) coating is used to determine the nonlinear properties. The estimated results clearly reveal a significant nonlinearity of the TS coating. The main advantage of this procedure is that it requires essentially no specimen preparation and allows continuous measurements after TS deposition. Furthermore, the data interpretation does not require complex computational models and calculations. This streamlined process makes the present method attractive when evaluations of many specimens are required. The present procedure can be also extended to identify nonlinear properties of other coatings/films on substrates.
Benign Breast Diseases: Classification, Diagnosis, and Management

Benign breast diseases constitute a heterogeneous group of lesions including developmental abnormalities, inflammatory lesions, epithelial and stromal proliferations, and neoplasms. In this review, common benign lesions are summarized and their relationship to the development of subsequent breast cancer is emphasized. The Oncologist 2006;11:435–449
Why do beliefs about intelligence influence learning success? A social cognitive neuroscience model

Students’ beliefs and goals can powerfully influence their learning success. Those who believe intelligence is a fixed entity (entity theorists) tend to emphasize ’performance goals,’ leaving them vulnerable to negative feedback and likely to disengage from challenging learning opportunities. In contrast, students who believe intelligence is malleable (incremental theorists) tend to emphasize ’learning goals’ and rebound better from occasional failures. Guided by cognitive neuroscience models of top–down, goal-directed behavior, we use event-related potentials (ERPs) to understand how these beliefs influence attention to information associated with successful error correction. Focusing on waveforms associated with conflict detection and error correction in a test of general knowledge, we found evidence indicating that entity theorists oriented differently toward negative performance feedback, as indicated by an enhanced anterior frontal P3 that was also positively correlated with concerns about proving ability relative to others. Yet, following negative feedback, entity theorists demonstrated less sustained memory-related activity (left temporal negativity) to corrective information, suggesting reduced effortful conceptual encoding of this material–a strategic approach that may have contributed to their reduced error correction on a subsequent surprise retest. These results suggest that beliefs can influence learning success through top–down biasing of attention and conceptual processing toward goal-congruent information.
Noise measurements of series SQUID arrays

Series arrays of 50 gradiometer superconducting quantum interference devices (SQUIDS) and 100 magnetometer SQUIDs have been fabricated using Nb/AlO/sub x//Nb junctions with a planarized all-refractory technology for superconductivity (PARTS), the white noise of these arrays has been measured. The individual devices are 50-pH, 2-hole and 100-pH, 1-hole SQUIDs with integrated single turn input coils, 1- mu m/sup 2/ and 0.5- mu m/sup 2/ junctions, and PtRh shunt resistors. The input coil inductance of 10 nH will effectively match with a wide bandwidth to miniature pick-up loop structures for various experiments. Ideally, the coupled energy sensitivity should remain constant as devices are added in series, while the output impedance rises to a level practical for direct coupling to room-temperature electronics. The output impedance of the arrays is 250-1000 Omega . The white noise was measured directly with an ultra low noise preamplifier at room temperature. The best result was Phi /sub N/=0.12 mu Phi /sub 0// square root Hz with a corresponding coupled energy sensitivity of 56 h. >
Biomimetic Processing of Ceramics and Ceramic-Metal Composites

Biomimetic design and processing of laminated B4C-Al cermets, based on knowledge gained from the microstructure-property characterization of abalone shells, is described. In the nacre section of the shell, the microstructure is highly organized as CaCO3 (aragonite) crystals, with a thickness of 0.25 μm, separated by a layer of organic matter 300–500 A thick. This organization forms a miniature “brick and mortar” microstructure. The resultant strength and fracture toughness of the nacre, i.e., 180 MPa and 7 MPa-m1/2 , are many orders of magnitude higher than those of monolithic CaCO3. The processing of laminated B4C-Al cermets, based on the microstructure of the nacre, was performed by a combination of tape casting of the ceramic and infiltration of the metal. The resultant cermets displayed a 40% increase in both fracture toughness and strength over monolithic B4C-Al cermets.
Choice of inbred rat strain impacts lethality and disease course after respiratory infection with Rift Valley Fever Virus.

Humans infected with Rift Valley Fever virus (RVFV) generally recover after a febrile illness; however, a proportion of patients progress to a more severe clinical outcome such as hemorrhagic fever or meningoencephalitis. RVFV is naturally transmitted to livestock and humans by mosquito bites, but it is also infectious through inhalational exposure, making it a potential bioterror weapon. To better understand the disease caused by inhalation of RVFV, Wistar-Furth, ACI, or Lewis rats were exposed to experimental aerosols containing virulent RVFV. Wistar-Furth rats developed a rapidly progressing lethal hepatic disease after inhalational exposure; ACI rats were 100-fold less susceptible and developed fatal encephalitis after infection. Lewis rats, which do not succumb to parenteral inoculation with RVFV, developed fatal encephalitis after aerosol infection. RVFV was found in the liver, lung, spleen, heart, kidney and brain of Wistar Furth rats that succumbed after aerosol exposure. In contrast, RVFV was found only in the brains of ACI or Lewis rats that succumbed after aerosol exposure. Lewis rats that survived s.c. infection were not protected against subsequent re-challenge by aerosol exposure to the homologous virus. This is the first side-by-side comparison of the lethality and pathogenesis of RVFV in 3 rat strains after aerosol exposure and the first step towards developing a rodent model suitable for use under the FDA Animal Rule to test potential vaccines and therapeutics for aerosol exposure to RVFV.
Disaster Management in the United States: Examining Key Political and Policy Challenges

The failures associated with the Hurricane Katrina response call attention to the challenges of, and the need to better understand disaster management practices in the United States. This article reviews several recent contributions to the field of disaster research and considers four key issues: the concept of disaster vulnerability, how individuals respond to hazard risks, challenges associated with effective hazard mitigation, and the idea of policy learning in the area of disasters. Beyond a review of these aspects of disaster management, future directions in disaster research is discussed.
Towards enabling more effective locomotion in VR using a wheelchair-based motion platform

This paper addresses two questions relevant to the design of effective locomotion methods for VR using a novel wheelchair motion simulation interface. First, we investigate the extent to which people's ability to keep track of where they are in an immersive virtual environment can be facilitated by actual physical movement (rotation and translation) in the context of vehicular travel. Second, we quantitatively analyze various characteristics of the travel paths produced by different types of locomotion control systems to gain insight into the aspects of control that can evoke or impede natural patterns of movement through a virtual environment. In a within-subjects experiment, we asked 35 volunteers to virtually search through 16 identical-looking boxes randomly placed within a realistically rendered, circularly symmetric virtual room to find 8 hidden targets. Participants performed this task under four different conditions of integrated visual and physical movement, controlled via a joystick interface attached to a motorized wheelchair. In all four cases participants 'drove' their virtual viewpoint using the joystick, but the nature of the accompanying physical movement varied between the conditions. The four conditions were: no physical movement; full physical rotation only; full physical translation and rotation; and "partial" physical translation and rotation, wherein the extent of the actual physical movement was proportionally reduced relative to the visually-indicated movement. Analysis of the search results did not find a statistically significant main effect of the physical movement condition on total distance traveled or total number of revisits to previously searched locations. However we did see a trend towards greater search accuracy in the full physical motion condition, with a greater proportion of perfect trials, a smaller proportion of failed searches, fewer boxes revisited on average, and more novel boxes searched before the first revisit in that condition than in the others. Analyzing the paths traveled, we found that the velocity and curvature profiles of the virtual motion paths enabled by our novel joystick-controlled wheelchair motion simulation interface were more qualitatively similar to those produced by natural walking than were travel paths we had previously observed when more basic joystick locomotion control methods were used. This suggests potential benefits in adopting a vehicle-simulation movement control method for joystick locomotion control in VR.
Comparative responses of freshwater organisms to exposures of a commercial naphthenic acid

Abstract Comparative toxicity studies using unconfounded exposures can prioritize the selection of sensitive sentinel test species and refine methods for evaluating ecological risks of complex mixtures like naphthenic acids (NAs), a group of organic acids associated with crude oils and energy-derived waters that have been a source of aquatic toxicity. The objectives of this study were to compare responses of freshwater aquatic organisms (vertebrate, invertebrates, and a macrophyte; in terms of acute toxicity) to Fluka commercial NAs and to compare measured toxicity data with peer-reviewed toxicity data for other commercial NA sources and energy-derived NA sources. Exposures were confirmed using high performance liquid chromatography. Responses (7-d LC50s/EC50) ranged from 1.9 mg L−1 for Pimephales promelas to 56.2 mg L−1 for Typha latifolia. Following P. promelas in order of decreasing sensitivity were Ceriodaphnia dubia (7-d LC50 = 2.8 mg L−1), Hyalella azteca (7-d LC50 = 4.1 mg L−1), Chironomus dilutus (7-d LC50 = 6.5 mg L−1), and T. latifolia (7-d EC50 = 56.2 mg L−1), indicating that in terms of sensitivities, fish > invertebrates > plant for Fluka NAs in this study. Factors that affect exposures and measurements of exposures differ among commercial and energy-derived NAs and constrain comparisons. Despite differences in exposures, fish and invertebrates were relatively sensitive to both commercial and energy-derived NA sources (based on laboratory measurements and peer-reviewed data) and could be appropriate sentinel species for risk evaluations.
Effect of estrogens on early development of frog embryos.

SummaryAbnormalities were produced in the developing eggs of Rana pipiens and Rana clamitans by exposure to diethylstilbestro and to estrone in varying concentrations and for varying lengths of time. Higher concentrations of both substances produced more abnormalities, and estrone was found to be more effective than diethylstilbestrol.