cssi/SciSciGPT-SciSciNet huggingface dataset:
Aztec Middle College: High School Alternatives in Community Colleges

The traditional high school model derived from the factory deficit model of the early 1900s has left many students, mainly minorities and/or low socioeconomic students, disenfranchised. This is evident in the poor school performance and high dropout rates of such students. Whereas the factory deficit model was created to promote only a few high school students to college, the rest of the students were trained for factory jobs. Today's job market requires that high school students go to college subsequent to their graduation. For this reason, middle college alternatives to traditional high schools are being adopted. Although research on middle colleges is limited due to their recent development, the results are encouraging: high school students who would otherwise have failed school or dropped out have high attendance rates and high graduation rates.
Protective effect of C5a receptor inhibition after murine reperfused stroke.

OBJECTIVE The complement cascade has been implicated in cerebral ischemia/reperfusion injury. To develop clinically useful therapies that successfully manipulate the complement cascade, the individual roles of its components must be clearly defined. Previous studies have shown that C5 inhibition improves outcome after experimental stroke. In this study, we investigated the role of C5a in stroke injury by inhibiting its activity at the receptor level.
Creating and Diffusing a Technology Champion Course

Excitement has been generated for using Internet technology as a vehicle to further numerous educational objectives, including enhanced student learning, greater integration of business school functional areas, and increased job market relevance. This article discusses how the Introductory Internet Marketing course can be positioned as a technology champion to accomplish a number of these marketing education objectives. Following this, a plan to diffuse the activities from the champion course to other marketing courses is presented.
Evidence that neurons of the paraventricular nucleus of the hypothalamus with projections to the spinal cord are sensitive to the toxic effects of N-methyl aspartic acid

Controversy exists concerning the sensitivity of neurons of the paraventricular nucleus (PVN) of the hypothalamus to the toxic effects of N-methyl aspartic acid (NMA). To further investigate this problem, male golden hamsters (Mesocricetus auratus) received unilateral intrahypothalamic injections of NMA, coupled with injections of horseradish peroxidase into the area of the spinal cord which receives projections from the PVN. Histological evaluation of the brains showed that the NMA injections destroyed PVN neurons that project to the spinal cord. These results are discussed in reference to previous reports on the effects of NMA injections on photoperiod-dependent seasonal cycles in hamsters.
Combined quantitative analysis of attenuation corrected and non-corrected myocadial perfusion SPECT: Method development and clinical validation

Background Attenuation corrected myocardial perfusion SPECT (AC-MPS) has been demonstrated to improve the specificity of detecting coronary artery disease (CAD) by visual analysis which utilizes both non-corrected (NC) and AC data. However, the combined automated quantification of NC and AC-MPS has not been previously described. We aimed to develop a combined quantitative analysis from AC and NC data to improve the accuracy of automated detection of CAD from AC-MPS.
An automated system for optimizing post-disaster temporary housing allocation

In the aftermath of natural disasters, emergency management agencies need to provide adequate temporary housing solutions to accommodate the large number of displaced families. Disaster impact software systems, such as HAZUS-MH (FEMA) and MAEviz (MAE Center), enable emergency planners to estimate the expected displacement of families after natural disasters; however they lack the capability of providing temporary housing solutions. This paper presents the development of an automated system to support decision-makers in optimizing post-disaster temporary housing arrangements. The system has been integrated in MAEviz and provides the capability of optimizing a number of important objectives, including minimizing negative socioeconomic impacts, maximizing housing safety, minimizing negative environmental impacts, and minimizing public expenditures; in addition to other user-defined objectives. The system consists of three main models: (1) data collection; (2) automated optimization; and (3) output analysis and visualization. A large-scale application example is optimized to illustrate the use of the system and demonstrate its unique capabilities.
Modulation-transfer-function analysis for sampled image systems.

Sampling generally causes the response of a digital imaging system to be locally shift-variant and not directly amenable to Modulation Transfer Function (MTF) analysis. However, this paper demonstrates that a meaningful system response can be calculated by averaging over an ensemble of point-source system inputs to yield an MTF which accounts for the combined effects of image formation, sampling, and image reconstruction. As an illustration, the MTF of the Landsat MSS system is analyzed to reveal an average effective instantaneous field of view which is significantly larger than the commonly accepted value, particularly in the along-track direction where undersampling contributes markedly to an MTF reduction and resultant increase in image blur.
Synthesis of Poly(terephtha1ic Anhydride) by Hydrolysis of Terephthaloyl Chloride/Triethylamine Intermediate Adduct. Characterization of Intermediate Adduct

Terephthaloyl chloride and triethylamine in a 1:2 ratio react in acetone to form a solid adduct. On the basis of IR spectra, chemical properties, and by analogy to 1:1 adducts between acid chloride...
Secular changes in age at menarche in a sample of US women

In an epidemiological survey of the reproductive history of a large group of United States women who had given birth to at least one child, there was a secular trend in age at menarche between those born around 1920 and those born around 1940-45. The trend was linear and the increment 3.2 months (+/- 0.36) per decade. The women were White, well nourished, middle-class and resided in all parts of the United States.
Telecom-band single photon switch

We present a high-speed all-optical switch for use in quantum information processing. The demonstrated implementation is capable of operating on 1310-nm single photons. Its performance is characterized using polarization-entangled photon pairs.
Purification and Characterization of a-N-Acetylgalactosaminidase from Clostridium perfringens

Summary® - N -Acetylgalactosaminidasefrom Clostridiumperfringens isanexoglycosidasethatdegradesthehumanbloodtypeAepitope.Ahighlypuri”edpreparationof ® - N -acetylgalactosaminidasewasobtainedfrom C.perfringens bysaltprecipitation,gel”ltration,ion-exchangechromatography,chromatofocusing,andhigh-pressureliquidchromatography.The”nalpreparationwashomogeneousbysodiumdodecylsulfate – polyacrylamidegelelectrophoresis,withamolecularmassof72.1kDa.Theenzymewashighlyselectiveforter-minal N -acetyl- ® - D -galactosamineresidues.Noothersubstantialglycosidaseactivities,speci”callyneuraminidase,weredetected.ThepHoptimumoftheenzymewasbetween6.5and7.0,andactiv-itywasunaffectedbyionicstrength.Noproteaseactivitywasde-tectedandenzymeactivitywasstableat4 ± Cfor12months.ELISAexperimentsdemonstratedactivityagainstbloodtypeAepitope. IUBMB Life ,50:91 – 97,2000Keywords a - N -Acetylgalactosaminidase;bloodtypeAepitope; Clostridiumperfringens. INTRODUCTION Thecarbohydrateepitopesexpressedontheglycoproteinsandglycolipidsontheglycocaylxnotonlyareimportantinthegrowthanddevelopmentofeucaryotes(
Oscillatory Phenomena in Direct Current Glow Discharges

In glow discharges having a positive column with a constant emf and a series resistance, oscillations usually are observed in tube voltage, current, and light intensity. While current and voltage oscillations represent a modulation of only a few percent, the intensity decreases to zero between maxima in the positive column, but there is an appreciable steady component near the cathode. The intensity maxima move as positive striations toward the cathode, or as negative striations with a much higher speed toward the anode. Where positive and negative striations meet they stop for times up to 100 \ensuremath{\mu}sec.The oscillations are often very stable and repeat themselves without change for hours. Often several modes exist and the discharge moves back and forth between them and appears unstable.The data presented in this paper were obtained chiefly from argon discharges although similar phenomena occur in most other gases over a great range of pressure and current. A discussion of the mechanism producing the phenomena is given.
IGF-I improved bone mineral density and body composition of weaver mutant mice

Our recent report on a parallel decrease in the body weights and serum IGF-I levels of weaver mice suggests that IGF-I's endocrine function may be impaired in neurodegenerative diseases. To further understand the overall effects of IGF-I deficiency on the postnatal growth, we measured bone mineral density (BMD), bone mineral content (BMC), lean body mass (LBM) and fat mass in male and female weaver mice and wild-type littermates on D21 (prepuberty), D45 (puberty), and D60 (postpuberty) using dual-energy X-ray absorptiometry (DEXA). In both male and female weaver mice, we found that the levels of circulating IGF-I paralleled those of BMD, BMC, and LBM, but not the fat mass. Male weaver mice have normal fat mass at all three ages studied, whereas female weaver mice showed a trend to increase their fat mass as they mature. To determine whether circulating IGF-I is a determinant of body composition, we crossbred IGF-I transgenic mice with homozygous weaver mice, which resulted in a significant increase in circulating IGF-I levels in both male and female weaver mice and normalization of their BMD, BMC and body weights. In summary, our results demonstrated that normal circulating IGF-I levels are important in maintaining BMD, BMC, and body composition in neurodegenerative diseases, such as hereditary cerebellar ataxia.
Double layer charge and potential profiles at immiscible liquid/liquid electrolyte interfaces

Abstract Interfacial tension at the liquid/liquid interface between electrolyte solutions of nitrobenzene and water has been studied using a variation of the maximum bubble pressure method. This work provides a test of doubly-diffuse space charge theory for describing the potential profile across the interface and subsequent evaluation of the chi-potential (dipole potential) differnece. Electrocapillary curves were constructed by varying the concentration of tetraalkylammonium bromide salts (TAABr) in the aqueous phase while holding the concentration of the corresponding tetraalkylammonium tetraphenylborate salt (TAATPB) concentration constant in the nitrobenzene phase. Comparison of charges calculated through Gouy-Chapman-Verwey-Niessen theory with those experimentally determined, indicates the potential difference across the interface is concentrated in the diffuse layers in each phase. The chi potential drop across any interfacial compact layer is within experimental error (±5 mV) of zero mV.
Biochemical changes in fatty liver induced by choline or threonine deficiency. Part II. Various hepatic enzymic activities during the development of fatty livers in rats

Abstract The activities of various hepatic enzymes were determined in choline-deficient rats over an 8-day experimental period and in rats fed a low-protein diet primarily deficient in threonine over a 30-day experimental period. Supernatant fractions (10,000 g ) prepared from rat liver homogenates were assayed for glucose-6-phosphate (+6-phosphogluconate) dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase, α-glycerophosphate dehydrogenase, malic dehydrogenase, and glucose-6-phosphatase. Mitochondria isolated from rat liver homogenates were assayed for the electron transport system which catalyzes the DPN-mediated oxidation of TPNH by cytochrome c, isocitrate dehydrogenase, and α-glycerophosphate dehydrogenase. Of the enzymes assayed in the supernatant fractions (10,000 g ) of rat liver homogenates, only the dehydrogenases of the pentose phosphate pathway were significantly altered. A general increase in the specific activities of these enzymes occurred in all groups of rats irrespective of diet. It was concluded that the alteration in activity of these dehydrogenases may be indirectly related to the development of fatty liver by providing a source of available TPNH which could be utilized in the reductive reactions accompanying fat synthesis. Of the mitochondrial enzymes studied, only the electron transport system which catalyzes the DPN-mediated oxidation of TPNH was significantly decreased in fatty livers. The data did not permit assigning a direct cause or effect relationship between the lowered specific activity of this electron transport system and increased hepatic fat deposition; however, the correlation of lowered activity for this electron transport pathway and increased hepatic fat content was consistent.
Inviable immigrants drive diversification in the sea

Understanding how new species arise is central to evolutionary biology, and the study of speciation remains a vibrant frontier (1⇓⇓⇓–5). Although most evolutionary biologists agree that speciation occurs when populations become reproductively isolated from each other—meaning that they do not interbreed when they come into contact or, if they do interbreed, they fail to produce fertile offspring—a major challenge has been to explain how reproductive isolation comes about (5). A recent article in PNAS by Prada and Hellberg (6) addresses this important issue.
Risk of contrast-induced nephropathy in patients with normal renal function: iso-osmolar versus low-osmolar medium

Risk of contrast-induced nephropathy in patients with normal renal function: iso-osmolar versus low-osmolar medium
The effect of mixing events on the dynamics of pH1N1 outbreaks at small residential colleges.

Abstract Objective: The authors examine the dynamics and the impact of all-campus events on pH1N1 spread at Bates College in fall 2009, with comparisons to 3 other campuses. Participants: Students (N = 285) presented or called in to the Bates Health Center with symptoms consistent with influenza-like illness. Methods: Health Center staff at Bates collected data on the outbreak; data from other colleges are from Web sites and journal articles. Data were analyzed using a mathematical model for influenza. Results: Bates held 2 vaccine clinics mid-outbreak. The data are consistent with the hypothesis that the vaccine clinics may have altered routine student interactions, facilitating transmission of pH1N1 among students who otherwise might not have encountered each other. Conclusion: The vaccine clinics, held when vaccine became available, were too late to halt transmission. The disruptions to campus rhythms due to the vaccine clinics may instead have contributed to pH1N1 spread.
Intermolecular Interaction in Montmorillonites: NH-CO Systems*

The mechanism of interaction between cationic organic molecules satisfying exchange sites in montmorillonite and organic molecules with carbonyl groups was investigated. Dialkyl amides adsorbed on trimethyl-ammonium- and tetramethylammonium-montmorillonite were studied by i.r. spectroscopy. The electronegativity or basicity of the amides, expressed as a summation of the Taft polar factors (Σσ*), was found to be linearly related to the C-O stretching frequency after adsorption on trimethyl-ammonium-montmorillonite. Furthermore, the changes in the C—O and N—H stretching frequencies of the amides and trimethylammonium ion respectively, exhibited a direct linear relationship. Thus, the dialkyl amides were shown to be hydrogen bonded through the oxygen of the carbonyl group to the hydrogen of the trimethylammonium. The (001) spacing of trimethyl-ammonium-montmorillonite was 12·9 A Only after the adsorption of amide molecules of the size of N,N-diethylacetamide or larger did this spacing change. Dialkyl amides were adsorbed on tetramethylammonium-montmorillonite, but less energetically than on trimethylammonium-clay. The (001) spacing of tetramethylammonium-montmorillonite was 13·8 A and remained the same after adsorption of the dialkyl amides. Evidence of hydrogen bonding between the hydrogen of trimethylammonium-ion and some other carbonyl compounds was also noted.
500 mA AlGaAs/GaAs power heterojunction bipolar transistor

The current–voltage characteristics of 500 mA AlGaAs/GaAs power heterojunction bipolar transistors axe reported and the influence of case temperature on current handling capability and current gain are analysed. Current handling capabilities of 400–800 mA/mm per emitter periphery at different case temperatures have been successfully demonstrated using a low-doped GaAs layer as an emitter ballasting resistor to obtain a uniform current distribution over individual emitter fingers. A current gain of 50 at a collector current of 500 mA was realised at room temperature for three elementary devices bonded in parallel, each device comprised ten (5 × 25 μm2) emitter fingers.
Issues and Problems in the Conduct of Epidemiologic Research on Chronic Fatigue Syndrome

The epidemiologic research approach is perhaps most appropriate for initial studies of chronic fatigue syndrome since the syndrome is vaguely defined, scientific knowledge about it is limited, and an infectious etiology is suspected. Several priority needs appropriate for epidemiologic research are identified, including a refinement of diagnostic criteria; a greater understanding of the natural history of the syndrome; basic incidence, prevalence, and mortality statistics; information on whether asymptomatic cases exist; etiologic studies of possible heterogeneity of cases; investigations of clusters of cases; and determinations of whether patients with the syndrome have an increased risk of malignancy. Because of the lack of cogent etiologic hypotheses regarding the syndrome, case-control studies are identified as a high priority for research. The many difficulties encountered in conducting such research are discussed and approaches to dealing with these problems are suggested.
Rotator and crystalline films viaself-assembly of short-bond-length colloidal dimers

Nonspherical particles of pear-like and spherocylinder shape were organized into diverse two-dimensional (2D) structures, including the orientationally disordered rotator. Dry films with hexagonal, oblique, and centered rectangular symmetry were obtained by using convective assembly to condense and confine the system in a thin meniscus region. Monte Carlo simulations confirmed the transition from fluid to rotator simply as a function of system density and short-bond-length particle morphology.
Sodium alanate hydrogen storage system for automotive fuel cells

Abstract Suitability of Ti-catalyzed sodium alanate as a reversible hydrogen storage system for automotive polymer–electrolyte fuel cells has been assessed under the constraint that it must meet certain performance criteria with respect to the amount of recoverable H 2 needed for vehicle driving range, minimum full-flow of H 2 needed to satisfy vehicular power demands, maximum refueling time and minimum H 2 delivery pressure. It is assumed that the thermal energy for desorbing hydrogen is supplied by the fluid that cools the high-temperature membrane fuel cell stack operating at 120 ∘ C . It is found that a ten-fold enhancement in published desorption kinetics is needed to attain 90% reversible H 2 storage capacity while satisfying the minimum full-flow requirement of 0.02 g H 2 /kWe. The catalyzed medium needs a metal foam support to facilitate heat removal necessary for 0.5–1.5 kg/min H 2 refueling rate. The faster the refueling rate, the higher is the peak heat transfer rate and the lower is the amount of recoverable H 2 . For a system with 5.6 kg recoverable H 2 , the peak heat transfer rate during refueling can exceed 1 MW. The overall specific energy and energy density of the storage medium are functions of the packing density of the metal hydride powder. The minimum acceptable hydrogen delivery pressure from the storage device determines the hydrogen storage capacity but otherwise has small influence on sorption kinetics.
Concomitant robotic mitral and tricuspid valve repair: technique and early experience.

Background Robotic mitral valve repair has been successfully performed since the late 1990s, but concomitant robotic tricuspid repair has not yet been widely adopted. We report our first 5 years' experience with concomitant robotic mitral-tricuspid valve repair. Methods Records were reviewed for all patients who underwent concomitant robotic mitral-tricuspid valve repair in a single practice. Cardiopulmonary bypass was performed with femoral cannulation, antegrade and retrograde cardioplegia, and aortic cross-clamping by balloon occlusion. Access was through 5 ports. Tricuspid repair techniques included De Vega, modified De Vega with annuloplasty band, and annuloplasty band with interrupted suture repair. Results From August 2006 to December 2011, 50 patients underwent concomitant robotic mitral-tricuspid valve repair. The mean age was 73.4±9.3 years, and all patients had mitral or tricuspid regurgitation grades of 2+ or greater preoperatively. Cross-clamp and cardiopulmonary bypass times decreased significantly with surgeon experience. There were no conversions to sternotomy and one conversion to mitral valve replacement. Six patients required reexploration for bleeding or hemothorax, most of them early in the series. There were no infections, no intraoperative strokes, and no new-onset acute renal failure requiring dialysis. Two postoperative strokes resolved completely. Two patients experienced nitinol clip fracture and mitral ring dehiscence requiring reoperation. There were 2 early deaths. All patients had regurgitation grades of less than 2 at follow-up ( p Conclusions Combined robotic mitral-tricuspid valve repair can be performed safely and reproducibly, with acceptable early results. Long-term follow-up will be needed to establish this as an alternative to traditional sternotomy approaches.
Teachers' Beliefs about the Nature of Science and Their Relationship to Classroom Practice.

The effect of teachers' beliefs about the nature of science on their classroom practice was exam ined. Three science teachers were interviewed to elucidate their understanding of science and scienc...
Accelerated simulation of ultracapacitors using waveform relaxation method

Waveform-relaxation method is applied to ultracapacitor transmission line model to reduce the simulation time. Circuit partitioning, time windowing, and scheduling algorithms are developed and integrated in the waveform relaxation method to further accelerate the simulation. The transient response of the state variables of the transmission line model are simulated using the conventional method and developed model. The results show that the waveform relaxation method significantly decreases the simulation time while preserving the model accuracy.
Generating testable socio-technical systems theory

Abstract Suggestions for enhancements to socio-technical systems (STS) theory are offered based on a multiyear development process. First, researchers engaged in an iterative process of working with socio-technical systems (STS) and non-STS practitioners of organizational design to operationalize STS theory. Second, the operationalized theory was validated using an 86-company survey. Third, the operationalized theory was field-tested to discover its usability for practitioners addressing real-world organizational design problems.
Studying the Dynamics and Biological Significance of the Hudson River Using an Ocean Observatory

The Lagrangian Transport and Transformation Experiment (LaTTE) was designed to quantify how physical, biological and chemical processes transform material in a buoyant river plume and to link these processes to wind forced changes in the plume structure. The three LaTTE field programs include a May 2004 pilot, a full scale effort in April 2005, and a final study planned for May 2006. In each field study, dye is released and tracked by two vessels for physical, biological and chemical sampling of the tagged water mass. The field study and data assimilation segments of LaTTE rely on a research-based coastal ocean observatory to provide a temporal and spatial context for these intensive process studies. The observatory includes a shelf-wide observational backbone (international satellites, nested HF Radars, and autonomous underwater gliders) that was locally enhanced with high-resolution relocatable moorings in the New York Bight apex for the process studies. During the experiments, a shore based operations center combined real-time datasets with forecasts from a high-resolution atmospheric model (WRF) and hindcasts from an ocean model (ROMS) to provide adaptive sampling guidance to the research vessels. Results from the April 2005 pilot and the May 2006 process study will be reviewed. During the strong outflows of April 2005, the ebb tide squirts flowing onto the shelf were observed to respond to a strong sea breeze, forming a recirculating eddy just south of the Harbor entrance. The eddy served as an incubator for biological productivity, resulting in high phytoplankton concentrations leading to depleted bottom dissolved oxygen in a location consistent with historical observations. Only a portion of the fresh river water entering the recirculation zone exited as the expected coastal current along the New Jersey shelf. Most of the freshwater was observed to flow cross-shelf along the southern flank of the Hudson Shelf Valley, consistent with historical remote sensing data. This newly observed transport pathway can have potentially significant impacts on material transport from the Hudson River plume onto the continental shelf. In 2006, wind driven circulation resulted in the plume advecting south along New Jersey and eventually detaching into two pieces. In 2006, wind driven ROMS forecasts were successful at predicting the transport of the river as validated by the drifters and glider data
The effects of intratracheally administered coarse mode particles on respiratory tract infection in mice

Abstract Because coarse mode particles are rarely studied in their existing size ranges (greatest mass about 5–7 μn, aerodynamic diameter), we investigated the effects of four such particles, quartz, ferric oxide, calcium carbonate, and sodium feldspar, on host defenses against bacterial pulmonary infection. Mice which received intratracheal instillations of 10, 33, and 100 μg mouse were exposed within an hour to aerosols of viable Streptococcus, and pneumonia-induced mortality was measured. At 33 and 100 μg mouse, all particles significantly increased mortality. At the lower dose, only Fe2O3 caused a significant increase in mortality. To evaluate potential delayed effects, mice were challenged with the bacteria 24 h after exposure to 100 μg particles/mouse. Delaying the challenge did not significantly alter the response, except for the sodium feldspar group for which a partial recovery was observed. When mice exposed to 100 μg particles/mouse received aerosols of Klebsiella pneumoniae 24 h later, there was no significant effect on pulmonary bactericidal activity. For the model system used, it appears that Fe2O3, CaCO3, and sodium feldspar have effects roughly equivalent to quartz.
Bioinformatics data mining using artificial immune systems and neural networks

Bioinformatics is a data-intensive field of research and development. The purpose of bioinformatics data mining is to discover the relationships and patterns in large databases to provide useful information for biomedical analysis and diagnosis. In this research, algorithms based on artificial immune systems (AIS) and artificial neural networks (ANN) are employed for bioinformatics data mining. Three different variations of the real-valued negative selection algorithm and a multi-layer feedforward neural network model are discussed, tested and compared via computer simulations. It is shown that the ANN model yields the best overall result while the AIS algorithm is advantageous when only the “normal” (or “self”) data is available.
Single-day methadone dose alteration: Detectability and symptoms

Three experiments were conducted in which detectability and symptomatic effects of acute (single-day) increases and decreases in the methadone dose of subjects on methadone maintenance were examined. Altered doses ranged from 0% to 200% of the stable methadone dose, which was typically 50 mg. In an initial experiment, explicit information was provided to subjects (N = 10) about the occurrence and size of altered doses. No explicit information was provided in a second experiment, but subjects (N = 14) could detect altered doses on the basis of taste. In the third experiment, subjects (N = 2) received no information about the direction, size, or schedule of altered doses. Large dose alterations (75% to 100% of stable dose) were reliably detected by subjects on methadone maintenance, although marked individual differences in sensitivity were apparent. With taste cues available, subjects underestimated the magnitude of dose decreases and increases by 50% and 75%. Without taste cues, subjects could reliably detect only decreased doses. Symptomatic effects related to direction and size of altered doses but not to information conditions. Withdrawal symptom checklist scores were elevated after large (75% to 100%) dose decreases under all information conditions, but few symptomatic effects were reported after dose increases under any information condition. Clinical Pharmacology and Therapeutics (1984) 36, 244–250; doi:10.1038/clpt.1984.170
A polyketide synthase acyltransferase domain structure suggests a recognition mechanism for its hydroxymalonyl-acyl carrier protein substrate.

We have previously shown that the acyl transferase domain of ZmaA (ZmaA-AT) is involved in the biosynthesis of the aminopolyol polyketide/nonribosomal peptide hybrid molecule zwittermicin A from cereus UW85, and that it specifically recognizes the precursor hydroxymalonyl-acyl carrier protein (ACP) and transfers the hydroxymalonyl extender unit to a downstream second ACP via a transacylated AT domain intermediate. We now present the X-ray crystal structure of ZmaA-AT at a resolution of 1.7 A. The structure shows a patch of solvent-exposed hydrophobic residues in the area where the AT is proposed to interact with the precursor ACP. We addressed the significance of the AT/ACP interaction in precursor specificity of the AT by testing whether malonyl- or methylmalonyl-ACP can be recognized by ZmaA-AT. We found that the ACP itself biases extender unit selection. Until now, structural information for ATs has been limited to ATs specific for the CoA-linked precursors malonyl-CoA and (2S)-methylmalonyl-CoA. This work contributes to polyketide synthase engineering efforts by expanding our knowledge of AT/substrate interactions with the structure of an AT domain that recognizes an ACP-linked substrate, the rare hydroxymalonate. Our structure suggests a model in which ACP interaction with a hydrophobic motif promotes secondary structure formation at the binding site, and opening of the adjacent substrate pocket lid to allow extender unit binding in the AT active site.
Dynamics of the outer radiation belt

Radial profiles of electron intensity and phase space density in the energy range of ∼0.7 to 8 MeV, between L values of 3 and 9, show that particle injections followed by fast radial diffusion lead to the main part of the outer radiation belt near L=4 to 5 during active periods. In quiet times the belt is supplied by inward diffusion from an external source. Various combinations of these two basic configurations are also seen.
Promoting Exercise Self-Efficacy With an Exergame

A new generation of exercise video games (exergames) shows promise as a tool to motivate and engage users in physical activity. However, little research has been conducted to examine whether exergames work equally well across diverse populations and contexts. Therefore, in the present study, the authors investigated the effects of an individual psychological difference factor and a specific contextual factor on the exercise experience using an exergame. They used the objective self-awareness theory as the theoretical underpinning. In a 2 (seeing the image of self on screen: seeing oneself vs. not seeing oneself) × 2 (body image dissatisfaction: low vs. high) between-subjects design experiment, the authors found significant interaction effects showing that the feature of seeing the image of self on screen provided by the exergame works positively for individuals with low body image dissatisfaction, yet works negatively for individuals with high body image dissatisfaction. The finding of the present study has significant implications for health professionals and individuals who use the new generation of exergames for physical activities.
Records of the proveditori degli cambiatori II. Seasonal and short-range influences

Abstract An alternative to classical tests for long-range memory is applied to a series of late medieval exchange rates for the Florentine gold florin.
Radiation damage effects in far-ultraviolet filters, thin films, and substrates.

Advances in vacuum ultraviolet thin-film filter technology have been made through the use of filter designs with multilayers of materials such as Al2O3, BaF2, CaF2, HfO2, LaF3, MgF2, and SiO2. Our immediate application for these filters will be in an imaging system to be flown on a satellite where a 2 × 9 RE orbit will expose the instrument to approximately 250 krad of radiation. Because to our knowledge no previous studies have been made on the potential radiation damage of these materials in the thin-film format, we report on such an assessment here. Transmittances and reflectances of BaF2, CaF2, HfO2, MgF2, and SiO2 thin films on MgF2 substrates, Al2O3 thin films on fused-silica substrates, uncoated fused silica and MgF2, and four multilayer filters made from these materials were measured from 120 to 180 nm before and after irradiation by 250 krad from a 60Co gamma radiation source. No radiation-induced losses in transmittance or reflectance occurred in this wavelength range. Additional postradiation measurements from 160 to 300 nm indicates 2–5% radiation-induced absorption near 260 nm in some of the samples with MgF2 substrates. From these measurements we conclude that far-ultraviolet filters made from the materials tested should experience less than 5% change from exposure to up to 250 krad of high-energy radiation in space applications.
Social problem solving as a moderating variable between negative life stress and depressive symptoms

The present study sought to investigate the moderating function that social problem-solving effectiveness serves in relation to negative stressful life events and depressive symptomatology. It was also hypothesized that knowledge of problem solving would improve upon the prediction of level of depressive symptoms beyond the assessment of stressful events. Results involving 462 undergraduate students provide support for both predictions. Specifically, findings from a multiple regression analysis indicated that (1) differences in reported depressive mood between subjects under high and low stress levels were minimal for individuals characterized as effective problem-solvers, relative to those persons with problem-solving scores reflective of ineffective problem solving; and (2) assessment of problem-solving scores and their interaction with stress level provided for an additional three times the amount of explained variance in predicting depression scores beyond life stress scores. Additionally, a cross-validation of the regression analysis was conducted and found to result in a minimal amount of shrinkage that could be due to samplespecific characteristics.
Representations of Spacetime Alternatives and Their Classical Limits

Different quantum mechanical operators can correspond to the same classical quantity. Hermitian operators differing only by operator ordering of the canonical coordinates and momenta at one moment of time are the most familiar example. Classical spacetime alternatives that extend over time can also be represented by different quantum operators. For example, operators representing a particular value of the time average of a dynamical variable can be constructed in two ways: first, as a projection onto the value of the time-averaged Heisenberg picture operator for the dynamical variable and, second, as the class operator defined by a sum over those histories of the dynamical variable that have the specified time-averaged value. We show by both explicit example and general argument that the predictions of these different representations agree in the classical limit and that sets of histories represented by them decohere in that limit.
Do boards know when they hire a CEO that is a good match? Evidence from initial compensation

Abstract Are CEO initial compensation packages based on variations in the expected match quality of the hiring firms? Using CEO tenure as a proxy for expected match quality, and a sample of CEO turnovers between 1992 and 2006, we find that CEOs that experience good matches, defined as tenures exceeding four years, have higher initial compensation packages. We also find evidence from exogenous switching regression models that inside CEOs receive a higher good match premium than outside CEOs. To account for economic and regulatory changes across our sample period, we divide our sample into three subsamples: 1992–1997, 1998–2002, and 2003–2006, and repeat our analyses. Even though the positive relation between expected match quality and initial compensation persists across all periods, we find that the good match premium for inside and outside CEOs does not differ in the post-2002 period. We attribute this result to increased board independence and changes in regulation (Sarbanes–Oxley) in the post-2002 sample period.
The influence of humic acid on the toxicity and bioavailability of selected trace metals

Abstract The influence of humic acid (HA) on the toxicity and bioavailability of hexavalent chromium and cadmium was evaluated using a common freshwater invertebrate, Daphnia pulex. The 0.5, 5.0 and 50 mg HA/l concentrations had little influence on either the acute toxicity or the bioavailability of hexavalent chromium. The acute toxicity of cadmium was increased, decreased or not influenced by HA, depending on the concentration of HA and the time point examined. There was a dose-related pattern of binding (a maximal decrease in percent free cadmium followed by metal release from HA) observed with HA and cadmium. The release of cadmium from the HA may have resulted from an associated time dependent decrease in pH.
Vectorization of a particle code used in the simulation of rarefied hypersonic flow

A limitation of the direct simulation Monte Carlo (DSMC) method is that it does not allow efficient use of vector architectures that predominate in current supercomputers. Consequently, the problems that can be handled are limited to those of one- and two-dimensional flows. This work focuses on a reformulation of the DSMC method with the objective of designing a procedure that is optimized to the vector architectures found on machines such as the Cray-2. In addition, it focuses on finding a better balance between algorithmic complexity and the total number of particles employed in a simulation so that the overall performance of a particle simulation scheme can be greatly improved. Simulations of the flow about a 3D blunt body are performed with 10 to the 7th particles and 4 x 10 to the 5th mesh cells. Good statistics are obtained with time averaging over 800 time steps using 4.5 h of Cray-2 single-processor CPU time.
Methods for Studying Fc Receptor Expression

Abstract In the past two decades, rapid progress has been made in the field of Fc receptors. One of the reasons for this development has been the advances and improvements in the methodologies used to detect and analyze Fc receptors. This review describes the methods used to detect the murine and human Fc receptors of the various immunoglobulin isotypes at the RNA, protein, and functional level. We have given special attention to the binding assays used to detect Fc receptors through immunoglobulins or anti-Fc receptor monoclonal antibodies as probes. The various Fc receptor types exhibit a marked heterogeneity and we present a list of reagents that can differentiate between the different Fc receptor forms. These methods can detect Fc receptors on the cell membrane, as well as the cytoplasmic and secreted forms. Recent advances in the use of PCR and RNA/DNA analyses to study Fc receptor detection, expression, and function are also reviewed. The advantages and drawbacks of the various experimental approaches are presented. In addition, an appendix provides detailed protocols for the detection of Fc receptors by confocal immunofluorescence microscopy, rosetting, cytofluorometry, immunoprecipitation, and PCR
States' Rights and Vested Interests

"Constitutional law," wrote Edward S. Corwin in 1941, "has always a central interest to guard."1 During much of the history of the American Republic this central interest has been private property. Political theory, always an important ingredient of constitutional law, also has some central interest to protect, and in the United States two of the more important constitutional or political theories that have been utilized to protect the vested rights of property, corporate as well as private, have been the theory of natural law, with its Anglo-Saxon emphasis on natural rights, and the dogma of states' rights, particularly since the day of John C. Calhoun. In some ways these doctrines have supplemented each other; at times they have been mutually inconsistent; and each, as is true of many political ideas, has been used as a double-edged sword which can cut in opposite directions. One of the most notable examples of the versatility of a political idea is to be found in the various purposes to which the principle of the law of nature or natural rights was bent, once as a revolutionary device to topple the altars of religion and the thrones of kings, and later as an instrument for the protection of the vested interests of property rights. In this regard natural law and natural rights doctrines served well the corporate masters of the American economy, not only in the opinions of Supeme Court judges which emphasized the natural rights of artificial persons at the expense of those of natural persons,2 but also served the purposes of the Liberty League in the 1930's and Senator Taft later in proclaiming liberty to all the land in a manner that was somewhat different from that used by the Minute Men or by those who stormed the Bastille. The doctrine of States' Rights, though less important than theories of natural law and natural rights, has nevertheless made significant contribu-
Invisible Women in America’s National Pastime . . . or, “She’s Good. It’s History, Man.”

American popular culture holds that girls do not play baseball, and any news to the contrary is greeted with incredulity. But girls and women have played the national pastime since the game was first invented, in spite of the fact that softball has served as a vehicle for the most strident sex segregation in American sports. This article traces the tenacious participation of girls and women from the 19th century to the U.S. Women’s National Team. Team USA medaled in the hard-fought, violence-marred Women’s World Cup Tournament of 2010 in Caracas, Venezuela. At home, the team is invisible, and the players must battle for access to the game. What can be done to open the doors for them?
Assay of galactosyltransferase by high-performance liquid chromatography

Abstract Galactosyltransferase catalyzes transfer of galactose from UDP-galactose to glucose or N-acetylglucosamine with resultant formation of galactosides and UDP. In this new assay galactosyltransferase activity is measured by determining UDP by isocratic high-performance liquid chromatography on an amino-bonded column monitored spectrophotometrically. Concurrently, uncreacted UDP-galactose and breakdown products arising from UDP-galactose (UMP and uridine) are also determined. The new technique does not require radioactive substrates, permits usage of saturating concentrations of UDP-galactose, and provides monitoring of side reactions.
Selection of Salmonella typhimurium mutants with altered serine transhydroxymethylase regulation.

In Salmonella typhimurium the glyA gene product, serine transhydroxymethylase (E.C. 2.1.2.1; L-serine:tetrahydrofolate-5,10-hydroxymethyltransferase) is responsible for the interconversion of serine and glycine. This reaction also provides the cell with one-carbon units from the 5,10-methylenetetrahydrofolate formed during glycine synthesis. Despite the importance of this enzyme, however, no mutants in which its regulation has been specificially altered have been isolated. To isolate such mutants, we have devised a selection procedure using a strain (glyA951) in which the serine transhydroxymethylase activity is reduced. When this enzyme is completely repressed, the mutant requires glycine for growth. Revertants which retain the glyA951 lesion, but no longer require glycine, have been isolated and the serine transhydroxymethylase regulation examined. One revertant has a 7-fold elevated serine transhydroxymethylase level, which can be repressed the normal amount (about 5-fold) when the cells are grown in supplemented media. Another revertant has only a 2-fold higher serine transhydroxymethylase level; however, the amount of repression is reduced. The new lesions in both mutants cotransduce with the glyA gene and are distinct from other mutations that alter the regulation of both serine transhydroxymethylase and the methionine biosynthetic enzymes.
Photolysis and the dimethylsulfide (DMS) summer paradox in the Sargasso Sea

Apparent quantum yields and rates of dimethylsulfide (DMS) photolysis were determined from Sargasso Sea seawater with the goal of assessing the extent to which photoreactions affect the unusually elevated upper ocean concentrations of DMS during the summer, the so-called DMS summer paradox. Apparent quantum yields determined with monochromatic radiation decrease exponentially with increasing wavelength and indicate that DMS photolysis is driven by ultraviolet (UV) radiation. The relative spectral partitioning differs between samples collected from the surface mixed layer (15 m) and from the chlorophyll a maximum (80 m), presumably because of differences in chromophoric dissolved organic matter (CDOM) quality (e.g., apparent degree of bleaching). Quantum yields are also temperature dependent, and an approximate doubling of photolysis rates occurs for a 208C increase in temperature. The significance of DMS photolysis to upper ocean sulfur budgets is explored using a multiyear (1992‐ 1994) DMS time series, concurrent irradiance determinations and temperature profiles, and estimates of CDOM absorption. Depth-integrated, mixed-layer DMS photolysis rates peak in the summer (15‐25 mmol m 22
Graphene Epitaxial Growth on SiC(0001) for Resistance Standards

A well-controlled technique for high-temperature epitaxial growth on 6H-SiC(0001) substrates is shown to allow the development of monolayer graphene that exhibits promise for precise metrological applications. Face-to-face and face-to-graphite annealing in a graphite-lined furnace at 1200 $^{\circ}\hbox{C}$ –2000 $^{\circ}\hbox{C}$ with a 101-kPa Ar background gas lowers the rates of SiC decomposition and Si sublimation/diffusion and thus provides a means to control the rate of graphene layer development. We studied a wide range of growth temperatures and times and describe the resulting sample surface morphology changes and graphene layer structures. The experimental results are compared to a kinetic model based on two diffusion processes: Si vapor diffusion in the Ar-filled gap and atomic diffusion through graphitic surface layers.