cssi/SciSciGPT-SciSciNet huggingface dataset:
Simplical volume of closed locally symmetric spaces of non-compact type

We show that closed, locally symmetric spaces of non-compact type have positive simplicial volume. This gives a positive answer to a question that was first raised by (Gromov in Inst Hautes Etudes Sci Publ Math 56:5, 1982).
Some Commercial Polymer Emulsions and Their Combination with Starch Dispersions for Stabilizing Soil Particles in Water

Starch can be converted to starch-g-poly(methyl acrylate) (S-g-PMA) latexes in a number of weight proportions, (S to PMA), that will give excellent stabilization of soil particles to water. To extend the study of additives for use as soil stabilizers we treated test soil samples with five different commercial polymer emulsions: three of acrylic type and two of ethylenic (polyethylene) type. Two of the acrylic emulsions, Acrylic DLR and Rhoplex WL92, fully stabilize soil at a treatment level of 0.2 g polymer/100 g soil; this is twice the treatment level required by the S-g-PMA latexes for full stabilization (defined as 90% retention of treated soil after wet sieving). The third acrylic emulsion, Rhoplex AC388, did not function as well as DLR or WL92. The two polyethylene emulsions, Mycon HD and Sunkem 301, did not stabilize soil to water as well as DLR or WL92. We examined physical mixtures of Amioca (waxy cornstarch), regular cornstarch, or cationic cornstarch and synthetic polymer emulsions and found that 50% of the acrylic polymers can be replaced with Amioca, and at the 0.2 g/100 g soil treatment level show the same or increased soil retention after wet sieving compared to polymer emulsion alone. Einige handelsubliche Polymeremulsionen und ihre Kombination mit Starkedispersionen zur Stabilisierung von Bodenpartikeln gegen Wasser. Starke kann in einer Anzahl von Gewichtsverhaltnissen (S:PMA) in Starke-Pfropf-Polymethylacrylat (S-g-PMA)-Latizes umgewandelt werden, welches eine ausgezeichnete Stabilisierung von Bodenpartikeln gegenuber Wasser bewirkt. Um die Untersuchung von Zusatzen zur Verwendung als Bodenstabilisatoren fortzufuhren, haben wir Bodenproben mit funf verschiedenen handelsublichen Polymeremulsionen behandelt, und zwar mit dreien vom Acryltyp und zweien vom Ethylen-(Polyethylen)-Typ. Zwei der Acrylemulsionen, Acrylic DLR und Rhoplex WL92 stabilisieren den Boden bei einer Behandlungsmenge von 0,2 g Polymer/100 g Boden vollstandig. Dies ist die zweifache Behandlungsmenge derjenigen von S-g-PMA-Latizes fur die vollstandige Stabilisierung (definiert als 90%ige Retention des behandelten Bodens nach der Nassiebung). Die dritte Acrylemulsion, Rhoplex AC388, wirkte nicht so gut wie DLR und WL92. Die beiden Polyethylenemulsionen, Mycon HD und Sunkem 301, stabilisierten den Boden gegenuber Wasser nicht so gut wie DLR und WL92. Wir pruften physikalische Mischungen aus Amioca (wachsige Maisstarke), normaler Maisstarke und synthetischen Polymeremulsionen und fanden, das 50% der Acrylpolymere durch Amioca ersetzt werden konnen und das die Behandlung mit 0.2 g/100 g Boden dieselbe oder hohere Bodenretention nach der Nassiebung zeigt im Vergleich zur Polymeremulsion allein.
Cognitive Pretesting and the Developmental Validity of Child Self-Report Instruments: Theory and Applications.

Objective In the context of the importance of valid self-report measures to research and evidence-based practice in social work, an argument-based approach to validity is presented and the concept of developmental validity introduced. Cognitive development theories are applied to the self-report process of children and cognitive pretesting is reviewed as a methodology to advance the validity of self-report instruments for children. An application of cognitive pretesting is presented in the development of the Elementary School Success Profile.
Evaluation of methods to estimate glomerular filtration rate versus actual drug clearance in patients with chronic spinal cord injury

A retrospective chart review. To evaluate different methods of estimating renal function compared with patient-specific vancomycin and aminoglycoside (AG) clearance (CLDRUG) in patients with spinal cord injury (SCI), and to develop a new equation to more accurately estimate glomerular filtration rate (GFR) in SCI patients in order to optimize dosing for vancomycin and AG. Veterans Affairs medical center in California, United States of America, tertiary care facility with the largest inpatient SCI center in the VA system. Retrospective data collection from patient records. Pharmacokinetic analysis was performed to obtain actual CLDRUG, which is compared with different methods of estimating GFR.A total of 310 patients were initially assessed; however, only 141 patients met the inclusion criteria, had a diagnosis of chronic SCI, and received vancomycin or AG with at least one drug level at steady state from January to December of 2008. All four equations evaluated to estimate GFR significantly overestimated CLDRUG: the Modification of Diet in Renal Disease equation by 141%, Cockcroft–Gault equation by 83%, Chronic Kidney Disease Epidemiology Collaboration equation by 82% and 24-h endogenous creatinine clearance by 71% (P<0.001). The modified Cockcroft–Gault equation (CLM) showed improvement, however, still overestimated CLDRUG by 39% (P<0.001). Thus, a new equation for SCI (CLSCI) was developed which underestimated CLDRUG by <5% (P=0.16). Compared with different methods of estimating GFR, CLSCI=2.3 × x0.7 (x equals CLM in ml min−1) more accurately estimates CLDRUG in chronic SCI patients.
CHRONIC OTITIS MEDIA WITH EFFUSION

This article addresses the issues of cause, diagnosis, and management of otitis media with effusion in children. The progression from acute otitis media to chronic otitis media with effusion is described, and points of intervention are identified. Current recommendations on management and treatment are presented, including a discussion of the Agency for Health Care Policy and Research guideline's on "Otitis Media with Effusion in Young Children."
Influence of the Background State on Rossby Wave Propagation into the Great Lakes Region Based on Observations and Model Simulations

AbstractThe authors investigate the relationship between hydrology in the Great Lakes basin—namely, overlake precipitation and transient Rossby waves—using the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis data and historical output from phase 3 of the Coupled Model Intercomparison Project (CMIP3). The preferred path of observed Rossby wave trains associated with overlake precipitation on Lake Superior depends strongly on season and appears to be related to the time-mean, upper-level flow. During summer and fall, the Northern Hemisphere extratropical jet is relatively narrow and acts as a waveguide, such that Rossby wave trains traversing the Great Lakes region travel along the extratropical Pacific and Atlantic jets. During other months, the Pacific jet is relatively broad, which allows more wave activity originating in the tropics to penetrate into the midlatitudes and influence Lake Superior precipitation. Analysis is extended to CMIP3 mod...
Investigating effects of copy number alterations on targeted therapy response using a conditioning-based model

Emerging targeted therapies have shown benefits such as less toxicity and higher effectiveness in specific types of cancer treatment; however, the accessibility of these advantages may rely on sufficient understanding of mechanisms causing resistance and correct identification of suitable patients, which remain highly immature. Based on the fact that copy number alterations (CNAs) may affect expression levels and regulatory activities, CNAs are assumed to be capable of interfering with signal transduction and influence targeted drug effectiveness. Considering the mechanism of action (MOA) of trastuzumab in the ERBB2-ERK signaling pathway, a conditioning-based model in which copy number alterations (CNAs) serve as latent parents modifying signal transduction is applied. Using mathematical induction, the upstream and downstream CNAs are found to have equal influence on drug effectiveness. Two scoring functions, M-score and R-value, are further proposed to provide qualitative and quantitative information regarding the unfavorableness of a CNA on drug utility and thereby shed light on personalized therapy.
On the solution of a class of problems in membrane theory of thin shells

Abstract I t is shown that membrane stresses in shells of revolution for the class of problems for which the normal stress resultants are of the form ƒ ( z ) cos θ and the shear stress resultant is of the form ƒ ( z ) sin θ admit a particularly simple solution in terms of a stress function U which has earlier been considered. This fact is illustrated by solving the problem of flexure of a cantilever shell, and also the problem of a shell with hydrostatic lateral load. The formulas for the latter case are specialized to the form which they assume for an ellipsoidal shell, to enable comparison with an earlier solution of this problem.
Size Does Matter: The Effects of Magnitude Representation Congruency on Price Perceptions and Purchase Likelihood

The numerical cognition literature suggests that numerical stimuli (and hence prices) are represented and encoded in memory as magnitude representations (i.e., judgments of relative “size”). The magnitude representation associated with the numerical value of a price may be the same as (congruent) or different from (incongruent) the magnitude representation associated with some other related dimension. We conducted 3 experiments to examine the effects of congruent versus incongruent magnitude representations on price perceptions and purchase intentions. We find that congruent magnitude representations result in more favorable price knowledge (i.e., greater value perceptions and lower price judgments) and increased purchase likelihood. Our findings suggest that consumers are not consciously aware of the role of magnitude representations in influencing price perceptions.
Experimental evidence that herbivory increases shoot density and productivity in a subtropical turtlegrass ( Thalassia testudinum ) meadow

The sea urchin, Lytechinus variegatus, has been estimated to consume between 50 and 90% of annual net aboveground production in selected turtlegrass (Thalassia testudinum) meadows in the eastern Gulf of Mexico. Nevertheless, turtlegrass persists where sea urchin grazing is intense. We hypothesized that turtlegrass productivity is stimulated by grazing, as has been reported from terrestrial grassland systems, and that this best explains the persistence of heavily grazed turtlegrass in St. Joseph Bay, Fla. This hypothesis was tested by manipulating sea urchin densities (0, 10, and 20 individuals/m2) in 1-m2 enclosures. These densities encompass the range of average densities at the study site and those reported in the literature. Changes in turtlegrass abundance (e.g., short shoot density and biomass), production by short shoots, and leaf width were monitored in these enclosures during the summer. Repeated-measures ANOVA showed that production by short shoots, leaf density/shoot, and leaf width decreased over time in all treatments. Leaf density/shoot and leaf width were not significantly impacted by grazing, nor did grazing significantly reduce seagrass biomass, but it did lead to significantly higher densities of short shoots than found in control cages. Our results indicate that turtlegrass compensates for the effects of sea urchin herbivory by increasing the recruitment of short shoots during the growing season. We estimate that this increased shoot density led to a 40% increase in net aboveground primary production (g dry weight/m2) in grazing treatments, which helps to explain the lack of significant reductions of sea grass biomass during the growing season.
History of the use of neutrons in radiation therapy

Abstract The early history of fast neutron therapy is emphasized and, where possible, related to the relevant reports which appear elsewhere in this issue. Some of the high points in the invention and development of the early cyclotrons are reviewed and their use in treating the first series of patients is discussed. The developments in neutron biology and neutron therapy, which followed soon after in England and elsewhere in Europe are touched upon. A compilation of the present on-going efforts, using both cyclotrons and D - T neutron generators, is given and a summary of the types of clinical neutron sources now available is listed.
Genetics of salivary protein polymorphisms

Human salivary PRPs are determined by six closely linked genes on chromosome 12p13.2. The many PRPs show complex electrophoretic patterns that differ between individuals and reflect numerous genetic polymorphisms. Frequent length and null polymorphisms are common among PRPs. Common themes emerge as a background for these PRP polymorphisms. First, posttranslational proteolysis occurs with double-banded patterns among acidic PRPs and the generation of numerous basic PRPs derived from precursor proteins. Specific mutations may interfere with proteolysis, preventing generation of double-banded acidic PRPs (as with the Pa protein) or of small basic PRPs from precursor proteins (as with Pm proteins). Second, single cysteine substitutions in PRPs (Pa from PRH1 and G1 8 from PRB3) may lead to disulfide bonded homodimers as well as heterodimers with salivary peroxidase. Third, frequent homologous and unequal crossing-over within the PRP gene cluster leads to frequent protein size-variants (intragenic events as with the G1 protein variants) and the generation of the PRB2/1 fusion gene (intergenic event) with deletion of the PRB1 coding region and absence of multiple PRB1 coded proteins (Ps, Pm, Pe) in PRB2/1 homozygotes. Fourth, null mutations may also be produced (as with PsO and G1 0) by single nucleotide changes.
Crystallins from rat lens are especially susceptible to calpain-induced light scattering compared to other species

PurposeTo compare the susceptibility of crystallins from various animal species to formation of light scattering elements after proteolysis by calpain II enzyme (EC 3.4.22.17).MethodsLens, total soluble proteins from: 12-day and 4-week old rat, fetal and adult bovine, 16-day embryonic and 10-week chicken, and young human cortex and nucleus were proteolyzed by either endogenous lens calpain or addition of purified calpain II for 24 h followed by incubation for up to 11 days. Absorbance of light at 405 nm estimated light scattering by crystallins; SDS-PAGE and 2D-electrophoresis assessed proteolysis on the crystallins.ResultsMost rapid light scattering occurred with total soluble proteins from young rat lens, either after adding purified calpain or by activating endogenous lens calpain with calcium. (Only rat lens showed activation of endogenous calpain II.) β-crystallin polypeptides from rat, bovine, human, and to a more limited extent, chick lens were partially proteolyzed by addition of purified calpain ...
Diverse responses of vegetation phenology to a warming climate

[1] Warming climates have been widely recognized to advance spring vegetation phenology. However, the delayed responses of vegetation phenology to rising temperature and their mechanisms are poorly understood. Using satellite and climate data from 1982 to 2005, we reveal a latitude transition zone of greenup onset in vegetation communities that has diversely responded to warming temperature in North America. From 40°N northwards, a winter chilling requirement for vegetation dormancy release is far exceeded and the decrease in chilling days by warming winter temperature has little impact on thermal-time requirements for greenup onset. Thus, warming spring temperature has constantly advanced greenup onset by 0.32 days/year. However, from 40°N southward, the shortened winter chilling days are insufficient for fulfilling vegetation chilling requirement, so that the thermal-time requirement for greenup onset during spring increases gradually. Consequently, vegetation greenup onset changes progressively from an early trend (north region) to a later trend (south region) along the latitude transition zone from 40–31°N, where the switch occurs around 35°N. The greenup onset is delayed by 0.15 days/year below 31°N.
Radiation Effects in High Electron Mobility Transistors: Total Dose Gamma Irradiation

AlGaAs/GaAs high electron mobility transistors (HEMTs) have been exposed to 90 Mrad(GaAs) of Co60 gamma radiation. Despite the heavy exposure, the peak transconductance for selected transistors was only diminished by approximately 4%. In addition, threshold voltage shifts of up to 80 mV were observed for both enhancement and depletion mode devices.
QUICK: A flexible full-system functional model

In this paper, we introduce the concept of full-system Complete-and-Rollback functional simulators that make efficient functional models in functional/timing partitioned simulators. Complete-and-Rollback functional simulators can efficiently drive simulators of resolutions ranging from functional-only to cycle-accurate for a wide range of simulated machines. Complete-and-Rollback functional models achieve their capabilities by executing instructions to completion, enabling their execution to be highly optimized, but providing rollback capabilities to enable on-the-fly modifications to the functional execution. We also introduce QUICK, an implementation of a full-system Complete-and-Rollback functional model that supports the x86 and PowerPC ISAs, boots unmodified Windows XP and Linux, and runs unmodified applications such as YouTube on Internet Explorer while fully supporting rollbacks, including across I/O operations. We present various case studies using QUICK and conduct performance analyses to demonstrate its simulation performance.
Techniques for physicochemical characterization of nanomaterials

Advances in nanotechnology have opened up a new era of diagnosis, prevention and treatment of diseases and traumatic injuries. Nanomaterials, including those with potential for clinical applications, possess novel physicochemical properties that have an impact on their physiological interactions, from the molecular level to the systemic level. There is a lack of standardized methodologies or regulatory protocols for detection or characterization of nanomaterials. This review summarizes the techniques that are commonly used to study the size, shape, surface properties, composition, purity and stability of nanomaterials, along with their advantages and disadvantages. At present there are no FDA guidelines that have been developed specifically for nanomaterial based formulations for diagnostic or therapeutic use. There is an urgent need for standardized protocols and procedures for the characterization of nanoparticles, especially those that are intended for use as theranostics.
Redox Cycles in Trimethylamine Dehydrogenase and Mechanism of Substrate Inhibition

The steady-state reaction of trimethylamine dehydrogenase (TMADH) with the artificial electron acceptor ferricenium hexafluorophosphate (Fc(+)) has been studied by stopped-flow spectroscopy, with particular reference to the mechanism of inhibition by trimethylamine (TMA). Previous studies have suggested that the presence of alternate redox cycles is responsible for the inhibition of activity seen in the high-substrate regime. Here, we demonstrate that partitioning between these redox cycles (termed the 0/2 and 1/3 cycles on the basis of the number of reducing equivalents present in the oxidized/reduced enzyme encountered in each cycle) is dependent on both TMA and electron acceptor concentration. The use of Fc(+) as electron acceptor has enabled a study of the major redox forms of TMADH present during steady-state turnover at different concentrations of substrate. Reduction of Fc(+) is found to occur via the 4Fe-4S center of TMADH and not the 6-S-cysteinyl flavin mononucleotide: the direction of electron flow is thus analogous to the route of electron transfer to the physiological electron acceptor, an electron-transferring flavoprotein (ETF). In steady-state reactions with Fc(+) as electron acceptor, partitioning between the 0/2 and 1/3 redox cycles is dependent on the concentration of the electron acceptor. In the high-concentration regime, inhibition is less pronounced, consistent with the predicted effects on the proposed branching kinetic scheme. Photodiode array analysis of the absorption spectrum of TMADH during steady-state turnover at high TMA concentrations reveals that one-electron reduced TMADH-possessing the anionic flavin semiquinone-is the predominant species. Conversely, at low concentrations of TMA, the enzyme is predominantly in the oxidized form during steady-state turnover. The data, together with evidence derived from enzyme-monitored turnover experiments performed at different concentrations of TMA, establish the operation of the branched kinetic scheme in steady-state reactions. With dimethylbutylamine (DMButA) as substrate, the partitioning between the 0/2 and 1/3 redox cycles is poised more toward the 0/2 cycle at all DMButA concentrations studied-an observation that is consistent with the inability of DMButA to act as an effective inhibitor of TMADH.
Self-regulation of timeout duration in the modification of disruptive classroom behavior

The effects of self-determination vs. teacher-determination of timeout duration on disruptive behavior were investigated in a group of 15 students in a special classroom who had learning disabilities and/or behavior problems. There were five phases to the study: In a repeated measures design each subject received timeout for 5 minutes, no timeout, 5 minutes timeout, selfdetermined timeout duration, and student = teacher-determined timeout duration. The overall effect of timeout was to reduce significantly the rate of disruptive behavior. The effects of various timeout conditions did not differ, indicating self-management of timeout duration was just as effective as when the teacher set the timeout duration.
CORRELATIONS FOR ESTIMATING THE DIFFUSIVITIES OF NITROUS OXIDE IN AQUEOUS SOLUTIONS OF DIETHANOLAMINE AND N-METHYLDIETHANOLAMINE AND THE SOLUTION DENSITIES AND VISCOSITIES

Experimentally measured diffusion coefficients of nitrous oxide in water, aqueous solutions of diethanolamine, aqueous solutions of N-methyldiethanolamine, and aqueous blends of diethanolamine and N-methyldiethanolamine have been used to arrive at a modified Stokes-Einstein correlation by using nonlinear least-squares filling. The average deviation of this correlation from the experimentally measured diffusion coefficients is about 13%. Comparisons are also made to the estimated diffusivities of nitrous oxide in the amine solutions which are obtained from the Wilke-Chang and Hayduk-Minhas correlations. The average deviations of the Wilke-Chang and Hayduk-Minhas correlations from the measured values are about 13% and 19%, respectively. Correlations were also presented for estimating the solution densities and viscosities. Predicted values for the solution densities and viscosities from these correlations deviate from experimentally measured values on average by 1.2% and 4.8% respectively.
Perovskite photovoltaics: life-cycle assessment of energy and environmental impacts

The past few years have witnessed a rapid evolution of perovskite solar cells, an unprecedented photovoltaic (PV) technology with both relatively low cost and high power conversion efficiency. In this paper, we perform a life cycle assessment for two types of solution-processed perovskite solar modules to shed light on the environmental performance of this promising class of PVs. One module is equipped with FTO glass, a gold cathode, and mesoporous TiO2 scaffold; the other is equipped with ITO glass, a silver cathode, and ZnO thin film. We develop comprehensive life cycle inventories (LCIs) for all components used in the modules. Based on the LCI results, we conduct life cycle impact assessment for 16 common life cycle impact indicators, Eco-indicator 99, and two sustainable indicators: the energy payback time (EPBT) and the CO2 emission factor. We compare the results of Eco-indicator 99, the EPBT, and the CO2 emission factor among existing PV technologies, and further perform uncertainty analysis and sensitivity analysis for the two modules. The results demonstrate that perovskite solar modules possess the shortest EPBT, and future research should be directed to improving the system performance ratio and the device lifetime, and reducing precious metal consumption and energy-intensive operations in order to lower the CO2 emission factor.
Visual Feature Binding Requires Reentry

Reentrant processing has been proposed as a critical mechanism in feature binding. To test this claim, participants were shown arrays of six pairs of crossed vertical and horizontal bars. In each pair, one bar was white; one was red, green, or blue. Identifying the orientation, but not the color, of the nonwhite bar in the target item required correct binding. Four dots appeared around one of the items (the target) and either disappeared with it or persisted for 300 ms after the array disappeared. This type of trailing mask is thought to interfere with target processing by disrupting reentry. Consistent with the hypothesis that binding requires reentrant processing, the trailing mask significantly reduced the accuracy of orientation but not color judgments. In a control condition, when the white bar was omitted, binding was no longer required, and both color and orientation were accurately reported.
On double-byte error-correcting codes

This correspondence shows that there is a flaw in the results presented by G. L. Feng et al. (see ibid., vol.44, no.3, p.1152-63, May 1998). A large family of the codes constructed are not double-byte error correcting codes as originally claimed.
Preventing Infectious Pulmonary Tuberculosis Among Foreign-Born Residents of the United States.

Objectives. We described risk factors associated with infectious tuberculosis (TB) and missed TB-prevention opportunities in foreign-born US residents, who account for almost two thirds of the nation’s TB patients.Methods. In a cross-sectional study at 20 US sites of foreign-born persons diagnosed with TB in 2005 through 2006, we collected results of sputum smear microscopy for acid-fast bacilli (a marker for infectiousness) and data on visa status, sociodemographics, TB-related care seeking, and latent TB infection (LTBI) diagnosis opportunities.Results. Among 980 persons with pulmonary TB who reported their visa status, 601 (61%) were legal permanent residents, 131 (13.4%) had temporary visas, and 248 (25.3%) were undocumented. Undocumented persons were more likely than permanent residents to have acid-fast bacilli–positive smears at diagnosis (risk ratio = 1.3; 95% confidence interval = 1.2, 1.4). Of those diagnosed 1 year or more after arrival, 57.3% reported LTBI screening opportunities; fewer than 2...
Complexity in a spatially uniform continuum fault model

Recently, Rice (1993) pointed out that, up to now, the self-organizing models which have produced complex nonperiodic se- quences of events have all been sensitive to the spatial discretization used, and thus did not have a well defined continuum limit. He went on the suggest that spatial nonuniformity or "inherent discreteness" may be a necessary ingredient in allowing the complexity to develop in these systems. In this paper, I present a counterexample to this suggestion: a spatially uniform model with a well defined continuum limit is shown to give rise to complex nonperiodic sequences. The complexity arises in the deterministic model from inertial dynamics with a velocity-weakening frictional instability, with the instability being stabilized at short lengthscales by a viscous term. The numer- ical restilts are shown to be independent of the spatial discretization for discretizations small compared to the viscous lengthscale. Fur- thermore, the qualitative feattires of the complexity produced are seen to be invariant with respect to two very different types of small scale cutoffs, implying a universality of the reslilts with respect to the details of the small scale cutoff.
The nonequilibrium region of an electrode in contact with a flowing thermal plasma

A model for a high-pressure thermal plasma flowing onto an electrode in stagnation flow geometry based on a continuum description of the flow is used to establish anode current density limitations. These limitations can be overcome at high anode current densities when ionization in the nonequilibrium boundary layer supplies the required ion current to the distant plasma. Two modes of anode operation (low and high current density modes) are identified and interpreted to be a difference between a diffuse and constricted mode of arc attachment. Although the flow field is highly idealized, the results provide insight as to the coupling of the ionizational nonequilibrium boundary layer to the flow field and the concomitant effect that this coupling has on anode current limitation. The quasi-neutral approximation used is expected to accurately describe the dynamics within the ionization nonequilibrium boundary layer. The anode saturation current (current density above which the anode must emit ions) strongly increases with increasing free stream velocity and anode temperature. These results have important implications for the understanding of high-power arc jet operation, and the use of high-power arc jets in low thrust space propulsion. >
Knowledge transfer in virtual systems development teams: an exploratory study of four key enablers

Knowledge transfer among geographically separated members is recognized as a critical ingredient for collaborative accomplishment of work in virtual teams. However, due to the "localness" of knowledge, such transfer of knowledge is believed to be inherently problematic; thus, it is important to develop a solid understanding of the factors that enable knowledge transfer in such contexts. Drawing on existing literature on knowledge management and virtual teamwork, we identify four Cs (communication, capability, credibility, and culture) associated with individuals who transfer significant amounts of knowledge to remote members. Next, we test the four Cs in the context of US-Norwegian virtual teams engaged in systems development. The volume of communication, the credibility of the communicator, and the nature of cultural values held (i.e., collectivism) by the communicator were found to significantly predict the extent of knowledge transferred; although, contrary to expectations, capability was not found to have a significant influence. A number of implications for virtual team participants and professional communicators are articulated. Avenues for future research are also suggested.
Pathogenesis of an Infectious Mononucleosis-like Disease Induced by a Murine γ-Herpesvirus: Role for a Viral Superantigen?

The murine γ-herpesvirus 68 has many similarities to EBV, and induces a syndrome comparable to infectious mononucleosis (IM). The frequency of activated CD8+ T cells (CD62Llo) in the peripheral blood increased greater than fourfold by 21 d after infection of C57BL/6J (H-2b) mice, and remained high for at least a further month. The spectrum of T cell receptor usage was greatly skewed, with as many as 75% of the CD8+ T cells in the blood expressing a Vβ4+ phenotype. Interestingly, the Vβ4 dominance was also seen, to varying extents, in H-2k, H-2d, H-2u, and H-2q strains of mice. In addition, although CD4 depletion from day 11 had no effect on the Vβ4 bias of the T cells, the Vβ4+CD8+ expansion was absent in H-2IAb–deficient congenic mice. However, the numbers of cycling cells in the CD4 antibody–depleted mice and mice that are CD4 deficient as a consequence of the deletion of MHC class II, were generally lower. The findings suggest that the IM-like disease is driven both by cytokines provided by CD4+ T cells and by a viral superantigen presented by MHC class II glycoproteins to Vβ4+CD8+ T cells.
The properties of thermal hillocks as a function of linewidth and process parameter in Al-on-chemical-vapor-deposited W films

The formation of hillocks has been studied as a function of process parameter in patterned and unpatterned Al98.5wt. %Si1.0wt. %Cu0.5wt. % films deposited on chemical-vapor-deposited W-coated substrates. The effects of linewidth, substrate temperature during film deposition, and sintering time and temperature on hillock size were investigated. Three types of hillocks are found: the “surface hillocks”, the “side hillock”, and the “line hillock”. These are further classified by their shapes. The surface hillock and side hillock, which have been seen previously, form on patterned metal lines having linewidths greater than the larger Al alloy grain sizes (~3 μm). None is seen on linewidths between 0.9 and 2 μm where long-range grain boundary diffusion cannot occur. A new type of hillock, the line hillock, is seen to occur on metal structures having linewidths of 0.6 μm. The line hillock is inconsistent with the current understanding of hillock formation and may present severe restrictions on the downsizing of ultra-large-scale integrated devices.
Evaluation of hospital factors associated with hospital postoperative venous thromboembolism imaging utilisation practices

Background Recent research suggests that hospital rates of postoperative venous thromboembolism (VTE) are subject to surveillance bias: the more hospitals ‘look for’ VTE, the more VTE they find. However, little is known about what drives variation in hospital VTE imaging rates. We conducted an observational study to examine hospital and market characteristics that were associated with hospital-level rates of postoperative VTE imaging, focusing on hospitals with particularly high rates. Methods For Medicare beneficiaries undergoing 11 major operations (2009–2010) at 2820 hospitals, hospital-level postoperative VTE imaging use rates were calculated. Hospital characteristics associated with hospital VTE imaging use rates were examined including case severity, size, ownership, VTE process measure adherence, accreditations, staffing, malpractice environment, and county market factors. Associations between explanatory variables and VTE imaging rates were assessed using quantile regressions at the 25th, median, 75th and 90th quantiles. Results Mean postoperative VTE imaging rates ranged from 85.26 (SD=67.38) per 1000 discharges in the lowest quartile of hospitals ranked by VTE imaging rates to 168.86 (SD=76.70) in the highest quartile. Drivers of high imaging rates at the 90th quantile were high resident-to-bed ratio (coefficient=51.35, p Conclusions Hospital teaching status, resident-to-bed ratio, malpractice environment and local market factors drive hospital postoperative VTE imaging use, suggesting that non-clinical forces predominantly drive hospital VTE imaging practices.
A dual detector β-ray imaging probe with γ-ray background suppression for use in intra-operative detection of radiolabeled tumors

The basic concepts for a dual detector b‘ imaging probe incorporating a method of c-ray background suppression were evaluated. The test devices consisted of a 1.2 cm2 b‘ imaging CaF 2 (Eu) scintillator disk optically coupled to a 1.7 mm thick, area-matched transparent di⁄user disk, which in turn was coupled to sets of 2] 2o r 4 ] 4m m 2by 10 mm long BGO, GSO or LSO scintillators, which acted as both c-detectors as well as light guides for the CaF 2 (Eu) scintillation light, which in turn are attached to a fiber optic bundle coupled to a multichannel photomultiplier. Pulse shape discrimination allowed identification of the detector of interaction and coincidence between the two detectors allowed selection of b‘-only events. This type imaging detector system was shown to be capable of producing high-resolution images of b‘ distributions while suppressing the events due to the 511 keV annihilation radiation background. GSO was found to be the detector of choice for this application. ( 1998 Elsevier Science B.V. All rights reserved.
Hardness of cut problems in directed graphs

We study the approximability of the multicut and the (non-bipartite) sparsest cut problems in directed graphs. In the multicut problem, we are a given a graph G along with k source-sink pairs, and the goal is to find a smallest subset of edges whose deletion separates all source-sink pairs. The sparsest cut problem has the same input, but the goal is to find a subset of edges to delete so as to minimize the ratio of deleted edges to the number of source-sink pairs that are separated by this deletion. Study of algorithms for cut problems is intimately connected to the dual notion of flows in networks, and many approximation algorithms for cut problems use a flow solution as a starting point. The best known approximation algorithm for directed multicut is based on this approach and gives an O(√n)-approximation. On the other hand, the gap between the maximum multicommodity flow and the minimum multicut is known to be Ω(min(k , log n)). While this flow-cut gap may be interpreted as an evidence of inherent difficulty in designing good approximation algorithms for directed multicut, the strongest hardness result known is an APX-hardness. Even assuming the Unique Games Conjecture, only an ω(1)-hardness is known. Similar bounds hold for the directed sparsest cut problem.Our main result is that directed multicut is Ω(log n / log log n)-hard to approximate unless NP ⊆ DTIME (npolylog n). We show that this hardness result holds even when we allow a bicriteria relaxation, where the approximate solution is required to separate only a constant fraction of the pairs. This bicriteria hardness allows us to infer an Ω(log n / log log n)-hardness for the directed (non-bipartite) sparsest cut problem.
Holding High Hopes: How High Schools Respond to State Accountability Policies

American public education faces increasing pressure to carry out its mission of preparing youths with the skills to compete in today's global economy and to participate constructively in a democratic society. As part of this pressure, policymakers have developed increasingly sophisticated accountability and support systems to steer schools towards improved performance. These "new accountability" approaches emphasize student performance over system inputs, focus on schools rather than school districts as units of improvement, and use public reporting of student outcomes and rewards and sanctions as ways to motivate schools to alter their curriculum and instructional practices (Fuhrman, 1999). These strategies embody two key assumptions: (a) that accountability systems can be made powerful enough to influence the behavior of schools; and (b) that schools have or will develop the capacity to identify, select, and implement policies and practices that will improve their performance. Working under these assumptions, state and national policymakers have set academic goals, defined incentives, and provided supports, expecting that these actions would motivate schools to expend resources on improving organization, curriculum, and practice, and that schools' responses would improve educational programs and instruction and, in turn, improve student outcomes. State and national assessment results show that student performance in many elementary schools has improved over the last decade. Some researchers have argued that a portion of these gains can be attributed to the pressures generated by state accountability systems that have set standards, focused attention, and created stronger incentives for improved performance (Carnoy & Loeb, 2004; Grissmer & Flanagan, 1998; Grissmer, Flanagan, Kawata, & Williamson, 2000; Hanushek & Raymond, 2002). High schools, however, have not experienced the same positive effects, and we know little about how high school staff respond to new external accountability pressures. The study (Gross & Goertz, 2005) reviewed in this issue of CPRE Policy Briefs provides insight into how teachers and administrators in American public high schools are influenced by and attempt to address the problems posed by standards based state accountability systems. Our analysis builds upon earlier studies that used smaller and less representative samples of secondary schools (e.g., Carnoy, Elmore, & Siskin, 2003), sometimes agreeing with and sometimes challenging their conclusions about the effects of increased accountability and high schools.
Gating Transition of Pentameric Ligand-Gated Ion Channels

Pentameric ligand-gated ion channels are an important family of membrane proteins and play key roles in physiological processes, including signal transduction at chemical synapses. Here, we study the conformational changes associated with the opening and closing of the channel pore. Based on recent crystal structures of two prokaryotic members of the family in open and closed states, respectively, mixed elastic network models are constructed for the transmembrane domain. To explore the conformational changes in the gating transition, a coarse-grained transition path is computed that smoothly connects the closed and open conformations of the channel. We find that the conformational transition involves no major rotations of the transmembrane helices, and is instead characterized by a concerted tilting of helices M2 and M3. In addition, helix M2 changes its bending state, which results in an early closure of the pore during the open-to-closed transition.
Relative survival of patients with supratentorial low-grade gliomas.

We sought to assess the population-based estimates of age-standardized survival among patients with lowgrade gliomas (LGG) and to determine the impact of age and time on relative survival (RS). Data from the Surveillance, Epidemiology, and End Results (SEER) program of NCI from 1973 through 2006 were analyzed to assess survival among 5037 patients. Relationships were modeled using Dickman’s piecewise constant hazards RS model. The 3- and 10-year age-standardized RS were 67% and 37%, respectively. When analyzed by age group, the 10-year overall survival (OS) and RS for children (age, <16 years), young adults (age, 16–39 years), adults (age, 40–64 years), and older patients (age, ≥65 years) were 86% and 86%, 61% and 62%, 40% and 43%, and 10% and 14%, respectively. The observed difference between OS and RS was larger among older patients (4%) and smallest among children (<1%). Older patients were 30.5 times (excess hazard ratio [eHR]; 95% confidence interval [CI], 20.3–50.0) as likely as young adults to die during the first year and 18.2 times as likely to die during the second year. Adults were 5.3 (eHR; 95% CI, 3.5–8.1) times as likely to die during their first year as young adults. In the remaining years, the observed survival differences were substantially decreased, and the presence of an age-by-follow-up interaction was observed. Survival among older patients with LGG was substantially different from the one computed for young adults and children. Despite the hazards across age groups not being proportional, RS does not provide additional information, compared with OS, in patients with LGG.
Immunization against a dominant tumor antigen abrogates immunogenicity of the tumor

To study the role of subdominant epitopes in tumor rejection we have used EL4 tumor cells and their ovalbumin (OVA)-transfected counterpart E.G7. Immunization of mice with irradiated EL4 cells conferred protection against challenge with EL4 and E.G7. Surprisingly, immunization with irradiated E.G7 cells did not protect against a subsequent challenge with EL4 or E.G7. Growth of E.G7 tumors in E.G7 immunized mice was not due to loss of expression of OVA or MHC I by the tumor cells in vivo. Adoptive transfer of OVA-specific transgenic T cells, immunization of mice with native or heat-denatured OVA or infection with a recombinant virus expressing OVA also failed to induce rejection of E.G7 tumors. Lack of immunogenicity of the OVA-expressing tumor could not be overcome by combination of a CD40 activating antibody with immunization against E.G7 or OVA. Our results suggest that immunization against subdominant epitopes is more effective than vaccination against dominant epitopes.
Acute kidney injury: Can remote ischaemic preconditioning prevent AKI?

A randomized multicentre controlled study of 240 cardiac surgery patients at high risk of acute kidney injury (AKI) has demonstrated that remote ischaemic preconditioning can reduce the rate of AKI and requirement for renal replacement therapy. These findings suggest this procedure could be a promising therapeutic option for this high-risk patient group.
Jean Elshtain on Families and Politics

Jean Elshtain's writings on feminism, families, and politics were both profoundly important to the development of feminist theory and, at times, deeply puzzling. Elshtain engaged with central texts of western political thought in ways that enabled and encouraged others to think through what it would mean to take women's lives seriously in all their ambiguity and complexity.
Dynamic Filtering of Time-Varying Sparse Signals via $\ell _1$ Minimization

Despite the importance of sparsity signal models and the increasing prevalence of high-dimensional streaming data, there are relatively few algorithms for dynamic filtering of time-varying sparse signals. Of the existing algorithms, fewer still provide strong performance guarantees. This paper examines two algorithms for dynamic filtering of sparse signals that are based on efficient $\ell _1$ optimization methods. We first present an analysis for one simple algorithm (BPDN-DF) that works well when the system dynamics are known exactly. We then introduce a novel second algorithm (RWL1-DF) that is more computationally complex than BPDN-DF but performs better in practice, especially in the case where the system dynamics model is inaccurate. Robustness to model inaccuracy is achieved by using a hierarchical probabilistic data model and propagating higher-order statistics from the previous estimate (akin to Kalman filtering) in the sparse inference process. We demonstrate the properties of these algorithms on both simulated data as well as natural video sequences. Taken together, the algorithms presented in this paper represent the first strong performance analysis of dynamic filtering algorithms for time-varying sparse signals as well as state-of-the-art performance in this emerging application.
Interrelationship of Rheumatoid Arthritis, Folic Acid, and Aspirin

Decreased serum folate (FA) levels were detected in 71% of 51 patients with rheumatoid arthritis (RA). Of 11 patients studied more intensively, only one fulfilled the usual hematologic criteria for FA deficiency. All, however, demonstrated an abnormally rapid plasma clearance of tritium-labeled pteroylglutamic acid (3HPGA). "Binding" of 3HPGA was evaluated by dialysis to apparent equilibrium and found to be significantly reduced in the sera of patients with RA. Common to all these patients was the ingestion of aspirin (ASA). Four RA patients not taking ASA had normal 3HPGA "binding". The 3HPGA "binding" of RA sera decreased as these patients were given increased ASA dosage and vice versa. The in vitro addition of ASA to normal sera reduced "binding" to the level detected in RA sera. Progressive increases in ASA resulted in progressive decreases in "binding". Aspirin given to three normal subjects reduced 3HPGA "binding" in all and serum FA in two. Precedents for ASA-induced structural change in binding proteins and for the relation between decreased binding and lowered serum levels are discussed. It is suggested that the low serum FA concentration and rapid plasma clearance of 3HPGA in RA might reflect ASA-induced alterations of FA binding, resulting in a redistribution rather than deficiency of this vitamin.