Hypotetical learning trajectory to anticipate mathematics anxiety in algebra learning based on the perspective of didactical situation theory

NASA Astrophysics Data System (ADS)

Yuliani, R. E.; Suryadi, D.; Dahlan, J. A.

2018-05-01

The objective of this research is to design an alleged teacher learning path or Hypotetical Learning Trajectory (HLT) to anticipate mathematics anxiety of students in learning algebra. HLT loads expected mathematics learning objectives, estimates the level of knowledge and understanding of the students, as well as the selection of mathematical activity in accordance with the learning competencies. This research uses educational design research method. The research steps consist of a preliminary design, experimental and retrospective analysis. Data were gathered from various sources, such as data is written during the research process of test results, documentation, sheet results of students' work, results of interviews, questionnaires, and video recordings. The subjects of the study were 10 junior high school students. Based on the research identified 2 students at the level of high anxiety, 7 people at medium anxiety level and 1 student at low anxiety level. High anxiety levels about 20%, was approximately 70% and approximately 10% lower. These results can be used as an evaluation and reflection for designing materials that can anticipate mathematics anxiety of students learning algebra concepts.

Arbitrary-level hanging nodes for adaptive hphp-FEM approximations in 3D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavel Kus; Pavel Solin; David Andrs

2014-11-01

In this paper we discuss constrained approximation with arbitrary-level hanging nodes in adaptive higher-order finite element methods (hphp-FEM) for three-dimensional problems. This technique enables using highly irregular meshes, and it greatly simplifies the design of adaptive algorithms as it prevents refinements from propagating recursively through the finite element mesh. The technique makes it possible to design efficient adaptive algorithms for purely hexahedral meshes. We present a detailed mathematical description of the method and illustrate it with numerical examples.

Relapsed prostate cancer with neuroendocrine differentiation and high serum levels of carcinoembryonic antigen without elevation of prostrate-specific antigen: a case report.

PubMed

Kinebuchi, Yoshiaki; Noguchi, Wataru; Irie, Kyoko; Nakayama, Tsuyoshi; Kato, Haruaki; Nishizawa, Osamu

2007-02-01

A 62-year-old man had been treated with combined androgen blockade due to cT2bN1M0 prostate cancer, and his serum prostate-specific antigen (PSA) levels decreased and remained under the level of 0.5 ng/mL during therapy. Approximately 40 months after the initial therapy, difficulty on urination and constipation developed gradually, and serum carcinoembryonic antigen (CEA) and pro-gastrin-releasing peptide (ProGRP) levels were high at this point. He underwent transrectal and transurethral biopsy of the prostate, which revealed adenocarcinoma positive for CEA and chromogranin A. He received palliative pelvic irradiation, and oral estramustine phosphate and etoposide combined therapy. Tumor markers decreased and clinical symptoms improved for several months. The patient died of encephalopathy of unknown etiology approximately 11 months after the relapse.

VISAR Analysis in the Frequency Domain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolan, D. H.; Specht, P.

2017-05-18

VISAR measurements are typically analyzed in the time domain, where velocity is approximately proportional to fringe shift. Moving to the frequency domain clarifies the limitations of this approximation and suggests several improvements. For example, optical dispersion preserves high-frequency information, so a zero-dispersion (air delay) interferometer does not provide optimal time resolution. Combined VISAR measurements can also improve time resolution. With adequate bandwidth and reasonable noise levels, it is quite possible to achieve better resolution than the VISAR approximation allows.

The Liquid Annular Reactor System (LARS) propulsion

NASA Technical Reports Server (NTRS)

Powell, James; Ludewig, Hans; Horn, Frederick; Lenard, Roger

1990-01-01

A concept for very high specific impulse (greater than 2000 seconds) direct nuclear propulsion is described. The concept, termed the liquid annular reactor system (LARS), uses liquid nuclear fuel elements to heat hydrogen propellant to very high temperatures (approximately 6000 K). Operating pressure is moderate (approximately 10 atm), with the result that the outlet hydrogen is virtually 100 percent dissociated to monatomic H. The molten fuel is contained in a solid container of its own material, which is rotated to stabilize the liquid layer by centripetal force. LARS reactor designs are described, together with neutronic and thermal-hydraulic analyses. Power levels are on the order of 200 megawatts. Typically, LARS designs use seven rotating fuel elements, are beryllium moderated, and have critical radii of approximately 100 cm (core L/D approximately equal to 1.5).

Methanogenic population dynamics during startup of a full-scale anaerobic sequencing batch reactor treating swine waste.

PubMed

Angenent, Largus T; Sung, Shihwu; Raskin, Lutgarde

2002-11-01

Changes in methanogenic population levels were followed during startup of a full-scale, farm-based anaerobic sequencing batch reactor (ASBR) and these changes were linked to operational and performance data. The ASBR was inoculated with anaerobic digester sludge from a municipal wastewater treatment facility. During an acclimation period of approximately 3 months, the ASBR content was diluted to maintain a total ammonia-N level of approximately 2000mg l(-1). After this acclimation period, the volatile solids loading rate was increased to its design value of 1.7g l(-1) day(-1) with a 15-day hydraulic retention time, which increased the total ammonia-N level in the ASBR to approximately 3,600 mg l(-1). The 16S ribosomal RNA (rRNA) levels of the acetate-utilizing methanogens of the genus Methanosarcina decreased from 3.8% to 1.2% (expressed as a percentage of the total 16S rRNA levels) during this period, while the 16S rRNA levels of Methanosaeta concilii remained low (below 2.2%). Methane production and reactor performance were not affected as the 16S rRNA levels of the hydrogen-utilizing methanogens of the order Methanomicrobiales increased from 2.3% to 7.0%. Hence, it is likely that during operation with high ammonia levels, the major route of methane production is through a syntrophic relationship between acetate-oxidizing bacteria and hydrogen-utilizing methanogens. Anaerobic digestion at total ammonia-N levels exceeding 3500mg l(-1) was sustainable apparently due to the acclimation of hydrogen-utilizing methanogens to high ammonia levels.

Host-Induced Gene Silencing (HIGS) of aflatoxin synthesis genes in peanut and maize: use of RNA interference and genetic diversity of Aspergillus

USDA-ARS?s Scientific Manuscript database

Approximately 4.5 billion people are chronically exposed to aflatoxins, these are powerful carcinogens produced by Aspergillus flavus and A. parasiticus. High levels of aflatoxins in crops result in approximately 100 million metric tons of cereals, ¬nuts, root crops and other agricultural products ...

Backside illuminated CMOS-TDI line scanner for space applications

NASA Astrophysics Data System (ADS)

Cohen, O.; Ben-Ari, N.; Nevo, I.; Shiloah, N.; Zohar, G.; Kahanov, E.; Brumer, M.; Gershon, G.; Ofer, O.

2017-09-01

A new multi-spectral line scanner CMOS image sensor is reported. The backside illuminated (BSI) image sensor was designed for continuous scanning Low Earth Orbit (LEO) space applications including A custom high quality CMOS Active Pixels, Time Delayed Integration (TDI) mechanism that increases the SNR, 2-phase exposure mechanism that increases the dynamic Modulation Transfer Function (MTF), very low power internal Analog to Digital Converters (ADC) with resolution of 12 bit per pixel and on chip controller. The sensor has 4 independent arrays of pixels where each array is arranged in 2600 TDI columns with controllable TDI depth from 8 up to 64 TDI levels. A multispectral optical filter with specific spectral response per array is assembled at the package level. In this paper we briefly describe the sensor design and present some electrical and electro-optical recent measurements of the first prototypes including high Quantum Efficiency (QE), high MTF, wide range selectable Full Well Capacity (FWC), excellent linearity of approximately 1.3% in a signal range of 5-85% and approximately 1.75% in a signal range of 2-95% out of the signal span, readout noise of approximately 95 electrons with 64 TDI levels, negligible dark current and power consumption of less than 1.5W total for 4 bands sensor at all operation conditions .

Exploratory Development of Improved Fatigue Strength Adhesives

DTIC Science & Technology

1974-11-01

fiber reinforced adhesives. A fifty-fold in-j crease in fatigue life at equivalent stress levels was achieved when a woven high modulus graphite...the stress level which could survive 10’ fatigue cycles was increased from approximately 30 percent of the ultimate shear strength with nylor knit...supports to as much as fifty percent with the high modulus fiber bond line reinforcement. The stress level which could withstand 10’ fatigue cycles

Development of a high-sensitivity and portable cell using Helmholtz resonance for noninvasive blood glucose-level measurement based on photoacoustic spectroscopy.

PubMed

Tachibana, K; Okada, K; Kobayashi, R; Ishihara, Y

2016-08-01

We describe the possibility of high-sensitivity noninvasive blood glucose measurement based on photoacoustic spectroscopy (PAS). The demand for noninvasive blood glucose-level measurement has increased due to the explosive increase in diabetic patients. We have developed a noninvasive blood glucose-level measurement based on PAS. The conventional method uses a straight-type resonant cell. However, the cell volume is large, which results in a low detection sensitivity and difficult portability. In this paper, a small-sized Helmholtz-type resonant cell is proposed to improve detection sensitivity and portability by reducing the cell dead volume. First, the acoustic property of the small-sized Helmholtz-type resonant cell was evaluated by performing an experiment using a silicone rubber. As a result, the detection sensitivity of the small-sized Helmholtz-type resonant cell was approximately two times larger than that of the conventional straight-type resonant cell. In addition, the inside volume was approximately 30 times smaller. Second, the detection limits of glucose concentration were estimated by performing an experiment using glucose solutions. The experimental results showed that a glucose concentration of approximately 1% was detected by the small-sized Helmholtz-type resonant cell. Although these results on the sensitivity of blood glucose-level measurement are currently insufficient, they suggest that miniaturization of a resonance cell is effective in the application of noninvasive blood glucose-level measurement.

Thermoelastic analysis of spent fuel and high level radioactive waste repositories in salt. A semi-analytical solution. [JUDITH

DOE Office of Scientific and Technical Information (OSTI.GOV)

St. John, C.M.

1977-04-01

An underground repository containing heat generating, High Level Waste or Spent Unreprocessed Fuel may be approximated as a finite number of heat sources distributed across the plane of the repository. The resulting temperature, displacement and stress changes may be calculated using analytical solutions, providing linear thermoelasticity is assumed. This report documents a computer program based on this approach and gives results that form the basis for a comparison between the effects of disposing of High Level Waste and Spent Unreprocessed Fuel.

RF extraction issues in the relativistic klystron amplifiers

NASA Astrophysics Data System (ADS)

Serlin, Victor; Friedman, Moshe; Lampe, Martin; Hubbard, Richard F.

1994-05-01

Relativistic klystron amplifiers (RKAs) were successfully operated at NRL in several frequency regimes and power levels. In particular, an L-band RKA was optimized for high- power rf extraction into the atmosphere and an S-band RKA was operated, both in a two-beam and a single-beam configuration. At L-band the rf extraction at maximum power levels (>= 15 GW) was hindered by pulse shortening and poor repeatability. Preliminary investigation showed electron emission in the radiating horn, due to very high voltages associated with the multi-gigawatt rf power levels. This electron current constituted an electric load in parallel with the radiating antenna, and precipitated the rf pulse collapse. At S-band the peak extracted power reached 1.7 GW with power efficiency approximately 50%. However, pulse shortening limited the duration to approximately 50 nanoseconds. The new triaxial RKA promises to solve many of the existing problems.

Fine resolution topographic mapping of the Jovian moons: a Ka-band high resolution topographic mapping interferometric synthetic aperture radar

NASA Technical Reports Server (NTRS)

Madsen, Soren N.; Carsey, Frank D.; Turtle, Elizabeth P.

2003-01-01

The topographic data set obtained by MOLA has provided an unprecedented level of information about Mars' geologic features. The proposed flight of JIMO provides an opportunity to accomplish a similar mapping of and comparable scientific discovery for the Jovian moons through us of an interferometric imaging radar analogous to the Shuttle radar that recently generated a new topographic map of Earth. A Ka-band single pass across-track synthetic aperture radar (SAR) interferometer can provide very high resolution surface elevation maps. The concept would use two antennas mounted at the ends of a deployable boom (similar to the Shuttle Radar Topographic Mapper) extended orthogonal to the direction of flight. Assuming an orbit altitude of approximately 100 km and a ground velocity of approximately 1.5 km/sec, horizontal resolutions at the 10 meter level and vertical resolutions at the sub-meter level are possible.

Fine Resolution Topographic Mapping of the Jovian Moons: A Ka-Band High Resolution Topographic Mapping Interferometric Synthetic Aperture Radar

NASA Technical Reports Server (NTRS)

Madsen, S. N.; Carsey, F. D.; Turtle, E. P.

2003-01-01

The topographic data set obtained by MOLA has provided an unprecedented level of information about Mars' geologic features. The proposed flight of JIMO provides an opportunity to accomplish a similar mapping of and comparable scientific discovery for the Jovian moons through use of an interferometric imaging radar analogous to the Shuttle radar that recently generated a new topographic map of Earth. A Ka-band single pass across-track synthetic aperture radar (SAR) interferometer can provide very high resolution surface elevation maps. The concept would use two antennas mounted at the ends of a deployable boom (similar to the Shuttle Radar Topographic Mapper) extended orthogonal to the direction of flight. Assuming an orbit altitude of approximately 100km and a ground velocity of approximately 1.5 km/sec, horizontal resolutions at the 10 meter level and vertical resolutions at the sub-meter level are possible.

The NaK 1 1,3delta states: theoretical and experimental studies of fine and hyperfine structure of rovibrational levels near the dissociation limit.

PubMed

Wilkins, A D; Morgus, L; Hernandez-Guzman, J; Huennekens, J; Hickman, A P

2005-09-22

Earlier high-resolution spectroscopic studies of the fine and hyperfine structure of rovibrational levels of the 1 3delta state of NaK have been extended to include high lying rovibrational levels with v < or = 59, of which the highest levels lie within approximately 4 cm(-1) of the dissociation limit. A potential curve is determined using the inverted perturbation approximation method that reproduces these levels to an accuracy of approximately 0.026 cm(-1). For the largest values of v, the outer turning points occur near R approximately 12.7 angstroms, which is sufficiently large to permit the estimation of the C6 coefficient for this state. The fine and hyperfine structure of the 1 3delta rovibrational levels has been fit using the matrix diagonalization method that has been applied to other states of NaK, leading to values of the spin-orbit coupling constant A(v) and the Fermi contact constant b(F). New values determined for v < or = 33 are consistent with values determined by a simpler method and reported earlier. The measured fine and hyperfine structure for v in the range 44 < or = v < or = 49 exhibits anomalous behavior whose origin is believed to be the mixing between the 1 3delta and 1 1delta states. The matrix diagonalization method has been extended to treat this interaction, and the results provide an accurate representation of the complicated patterns that arise. The analysis leads to accurate values for A(v) and b(F) for all values of v < or = 49. For higher v (50 < or = v < or = 59), several rovibrational levels have been assigned, but the pattern of fine and hyperfine structure is difficult to interpret. Some of the observed features may arise from effects not included in the current model.

The sub-chronic toxicity of regular White Spirit in rats.

PubMed

Carrillo, Juan-Carlos; Adenuga, M David; Mckee, Richard H

2014-10-01

Hydrocarbon solvents are mostly complex substances (UVCB) with carbon numbers in the range of approximately C5-C20. One of the most common types is a C9-C14 aliphatic solvent containing approximately 20% aromatics and commonly known as White Spirit in Europe and mineral spirits in the US. In previous repeated inhalation toxicity studies, White Spirit was reported to cause minimal systemic effects in most animal species with few effects other than male rat-specific kidney changes at levels up to approximately 2000mg/m(3). In the present study male and female rats were exposed to White Spirit vapors, 6h/day, 5days/week for 13weeks at levels of approximately 2000, 4000, or 8000mg/m(3) to assess the potential for effects at higher exposure levels. All of the rats survived the treatment period. In life observations were largely restricted to acute central nervous system (CNS) effects in the high exposure group. Terminal body weights of high exposure groups animals were significantly below control values. Statistically significant differences in the clinical and hematological observations were small and within normal physiological limits. Weights of some organs including liver, spleen and kidneys were elevated, but microscopic examination indicated that the only pathological effects were changes in the kidneys of the male rats, consistent with an α2u-globulin-mediated process, which is gender and species-specific and not relevant to humans. The overall no observed adverse effect level (NOAEC) was 4000mg/m(3). Copyright © 2014 Elsevier Inc. All rights reserved.

Will intra-specific differences in transpiration efficiency in wheat be maintained in a high CO₂ world? A FACE study.

PubMed

Tausz-Posch, Sabine; Norton, Robert M; Seneweera, Saman; Fitzgerald, Glenn J; Tausz, Michael

2013-06-01

This study evaluates whether the target breeding trait of superior leaf level transpiration efficiency is still appropriate under increasing carbon dioxide levels of a future climate using a semi-arid cropping system as a model. Specifically, we investigated whether physiological traits governing leaf level transpiration efficiency, such as net assimilation rates (A(net)), stomatal conductance (g(s)) or stomatal sensitivity were affected differently between two Triticum aestivum L. cultivars differing in transpiration efficiency (cv. Drysdale, superior; cv. Hartog, low). Plants were grown under Free Air Carbon dioxide Enrichment (FACE, approximately 550 µmol mol⁻¹ or ambient CO₂ concentrations (approximately 390 µmol mol⁻¹). Mean A(net) (approximately 15% increase) and gs (approximately 25% decrease) were less affected by elevated [CO₂] than previously found in FACE-grown wheat (approximately 25% increase and approximately 32% decrease, respectively), potentially reflecting growth in a dry-land cropping system. In contrast to previous FACE studies, analyses of the Ball et al. model revealed an elevated [CO₂] effect on the slope of the linear regression by 12% indicating a decrease in stomatal sensitivity to the combination of [CO₂], photosynthesis rate and humidity. Differences between cultivars indicated greater transpiration efficiency for Drysdale with growth under elevated [CO₂] potentially increasing the response of this trait. This knowledge adds valuable information for crop germplasm improvement for future climates. Copyright © Physiologia Plantarum 2012.

Accumulation, metabolism, and food-chain transfer of chlorinated and brominated contaminants in subadult white whales (Delphinapterus leucas) and narwhals (Monodon monoceros) from Svalbard, Norway.

PubMed

Wolkers, H; Lydersen, C; Kovacs, K M; Burkow, I; van Bavel, B

2006-01-01

The concentrations and patterns of polychlorinated biphenyls (PCBs), chlorinated pesticides, and polybrominated diphenyl ethers (PBDEs) were studied in white whales (Delphinapterus leucas) and narwhals (Monodon monoceros) from Svalbard, Norway. In addition, their main food items were included in the study. In the whales, a broad range of pollutants was found in relatively high concentrations. PCBs and pesticides were approximately 3000 and 8000 ng/g lipid, respectively, for white whales and three times higher for narwhals. PBDEs 47 were approximately 70 ng/g lipid for white whales and 170 ng/g lipid for narwhals. Compared with other marine mammals from the same area, contaminant levels are among the highest levels ever measured. These high levels are likely in part because of a decreased capacity to metabolize contaminants. Metabolic indices indicated that most compounds accumulate to the same degree in white whales and narwhals, but for some toxaphenes and chlordanes, narwhals might have a decreased metabolism and consequently a higher accumulation. The three-times-higher contaminant levels in blubber of narwhals was further explained by substantially higher contaminant levels in their more benthic diet. The high levels and broad pattern of accumulating pollutants make white whales and narwhals excellent indicators for a wide range of contaminants in the Arctic.

Two approximations for the geometric model of signal amplification in an electron-multiplying charge-coupled device detector

PubMed Central

Chao, Jerry; Ram, Sripad; Ward, E. Sally; Ober, Raimund J.

2014-01-01

The extraction of information from images acquired under low light conditions represents a common task in diverse disciplines. In single molecule microscopy, for example, techniques for superresolution image reconstruction depend on the accurate estimation of the locations of individual particles from generally low light images. In order to estimate a quantity of interest with high accuracy, however, an appropriate model for the image data is needed. To this end, we previously introduced a data model for an image that is acquired using the electron-multiplying charge-coupled device (EMCCD) detector, a technology of choice for low light imaging due to its ability to amplify weak signals significantly above its readout noise floor. Specifically, we proposed the use of a geometrically multiplied branching process to model the EMCCD detector’s stochastic signal amplification. Geometric multiplication, however, can be computationally expensive and challenging to work with analytically. We therefore describe here two approximations for geometric multiplication that can be used instead. The high gain approximation is appropriate when a high level of signal amplification is used, a scenario which corresponds to the typical usage of an EMCCD detector. It is an accurate approximation that is computationally more efficient, and can be used to perform maximum likelihood estimation on EMCCD image data. In contrast, the Gaussian approximation is applicable at all levels of signal amplification, but is only accurate when the initial signal to be amplified is relatively large. As we demonstrate, it can importantly facilitate the analysis of an information-theoretic quantity called the noise coefficient. PMID:25075263

A harmonic adiabatic approximation to calculate highly excited vibrational levels of ``floppy molecules''

NASA Astrophysics Data System (ADS)

Lauvergnat, David; Nauts, André; Justum, Yves; Chapuisat, Xavier

2001-04-01

The harmonic adiabatic approximation (HADA), an efficient and accurate quantum method to calculate highly excited vibrational levels of molecular systems, is presented. It is well-suited to applications to "floppy molecules" with a rather large number of atoms (N>3). A clever choice of internal coordinates naturally suggests their separation into active, slow, or large amplitude coordinates q', and inactive, fast, or small amplitude coordinates q″, which leads to an adiabatic (or Born-Oppenheimer-type) approximation (ADA), i.e., the total wave function is expressed as a product of active and inactive total wave functions. However, within the framework of the ADA, potential energy data concerning the inactive coordinates q″ are required. To reduce this need, a minimum energy domain (MED) is defined by minimizing the potential energy surface (PES) for each value of the active variables q', and a quadratic or harmonic expansion of the PES, based on the MED, is used (MED harmonic potential). In other words, the overall picture is that of a harmonic valley about the MED. In the case of only one active variable, we have a minimum energy path (MEP) and a MEP harmonic potential. The combination of the MED harmonic potential and the adiabatic approximation (harmonic adiabatic approximation: HADA) greatly reduces the size of the numerical computations, so that rather large molecules can be studied. In the present article however, the HADA is applied to our benchmark molecule HCN/CNH, to test the validity of the method. Thus, the HADA vibrational energy levels are compared and are in excellent agreement with the ADA calculations (adiabatic approximation with the full PES) of Light and Bačić [J. Chem. Phys. 87, 4008 (1987)]. Furthermore, the exact harmonic results (exact calculations without the adiabatic approximation but with the MEP harmonic potential) are compared to the exact calculations (without any sort of approximation). In addition, we compare the densities of the bending motion during the HCN/CNH isomerization, computed with the HADA and the exact wave function.

How the Mid-Victorians Worked, Ate and Died†

PubMed Central

Clayton, Paul; Rowbotham, Judith

2009-01-01

Analysis of the mid-Victorian period in the U.K. reveals that life expectancy at age 5 was as good or better than exists today, and the incidence of degenerative disease was 10% of ours. Their levels of physical activity and hence calorific intakes were approximately twice ours. They had relatively little access to alcohol and tobacco; and due to their correspondingly high intake of fruits, whole grains, oily fish and vegetables, they consumed levels of micro- and phytonutrients at approximately ten times the levels considered normal today. This paper relates the nutritional status of the mid-Victorians to their freedom from degenerative disease; and extrapolates recommendations for the cost-effective improvement of public health today. PMID:19440443

Review: correlations between oxygen affinity and sequence classifications of plant hemoglobins.

PubMed

Smagghe, Benoit J; Hoy, Julie A; Percifield, Ryan; Kundu, Suman; Hargrove, Mark S; Sarath, Gautam; Hilbert, Jean-Louis; Watts, Richard A; Dennis, Elizabeth S; Peacock, W James; Dewilde, Sylvia; Moens, Luc; Blouin, George C; Olson, John S; Appleby, Cyril A

2009-12-01

Plants express three phylogenetic classes of hemoglobins (Hb) based on sequence analyses. Class 1 and 2 Hbs are full-length globins with the classical eight helix Mb-like fold, whereas Class 3 plant Hbs resemble the truncated globins found in bacteria. With the exception of the specialized leghemoglobins, the physiological functions of these plant hemoglobins remain unknown. We have reviewed and, in some cases, measured new oxygen binding properties of a large number of Class 1 and 2 plant nonsymbiotic Hbs and leghemoglobins. We found that sequence classification correlates with distinct extents of hexacoordination with the distal histidine and markedly different overall oxygen affinities and association and dissociation rate constants. These results suggest strong selective pressure for the evolution of distinct physiological functions. The leghemoglobins evolved from the Class 2 globins and show no hexacoordination, very high rates of O(2) binding ( approximately 250 muM(-1) s(-1)), moderately high rates of O(2) dissociation ( approximately 5-15 s(-1)), and high oxygen affinity (K(d) or P(50) approximately 50 nM). These properties both facilitate O(2) diffusion to respiring N(2) fixing bacteria and reduce O(2) tension in the root nodules of legumes. The Class 1 plant Hbs show weak hexacoordination (K(HisE7) approximately 2), moderate rates of O(2) binding ( approximately 25 muM(-1) s(-1)), very small rates of O(2) dissociation ( approximately 0.16 s(-1)), and remarkably high O(2) affinities (P(50) approximately 2 nM), suggesting a function involving O(2) and nitric oxide (NO) scavenging. The Class 2 Hbs exhibit strong hexacoordination (K(HisE7) approximately 100), low rates of O(2) binding ( approximately 1 muM(-1) s(-1)), moderately low O(2) dissociation rate constants ( approximately 1 s(-1)), and moderate, Mb-like O(2) affinities (P(50) approximately 340 nM), perhaps suggesting a sensing role for sustained low, micromolar levels of oxygen.

The regulated in development and DNA damage response 2 (REDD2) gene mediates human monocyte cell death through a reduction in thioredoxin-1 expression.

PubMed

Imen, Jguirim-Souissi; Billiet, Ludivine; Cuaz-Pérolin, Clarisse; Michaud, Nadège; Rouis, Mustapha

2009-05-15

In a previous study, we identified the regulated in development and DNA damage response 2 (REDD2) gene as a highly expressed gene in human atherosclerotic lesions in comparison to normal artery, as well as in cultured human macrophages, and showed its implication in oxidized low-density lipoprotein (LDL)-induced macrophage death sensitivity. In this article, we attempt to identify the mechanism by which REDD2 induces such a phenomenon. Transient transfection of U-937 monocytic cells with a pCI.CMV.REDD2 expression vector increased by approximately twofold the mRNA levels of REDD2 in comparison to control cells transfected with pCI.CMV.GFP. Reactive oxygen species (ROS) production was significantly induced in REDD2-transfected cells compared with control cells (157+/-48 and 100+/-8 arbitrary units/mg cell protein, respectively; p<0.05). Moreover, a significant increase in parameters known to reflect the oxidative modifications of LDL was observed. Among enzymes involved in ROS production or degradation, we found a specific reduction in thioredoxin-1 (Trx-1) mRNA ( approximately 52+/-7% decrease, p<0.01 vs control cells) and protein ( approximately 60+/-4% decrease, p<0.001 vs control cells) levels in cells overexpressing REDD2 in comparison to control cells. In contrast, transfection of U-937 cells with siRNA against REDD2 decreased the mRNA levels of REDD2 by approximately 60% and increased Trx-1 mRNA and protein levels. Moreover, we observed no or a moderate increase in Bax (proapoptotic) and a significant decrease in Bcl2 (antiapoptotic) gene expression in cells that overexpress REDD2 compared to control cells. In addition, we showed that Trx-1 mRNA and protein levels were increased at low H(2)O(2) doses and decreased at higher doses. Interestingly, macrophages isolated from human atherosclerotic lesions differentially express REDD2 and Trx-1. Indeed, in certain patients, levels of REDD2 mRNA were low and those of Trx-1 mRNA were high. In contrast, in other patients, levels of REDD2 were high and levels of Trx-1 mRNA were low.

Preliminary post-emplacement safety analysis of the subseabed disposal of high-level nuclear waste

NASA Astrophysics Data System (ADS)

Kaplan, M. F.; Koplik, C. M.; Klett, R. D.

1984-09-01

The radiological hazard from the disposal of high-level nuclear waste within the deep ocean sediments is evaluated, on a preliminary basis, for locations in the central North Pacific and in the northwestern Atlantic. Radio-nuclide transport in the sediment and water column and by marine organisms is considered. Peak doses to an individual are approximately five orders of magnitude below background levels for both sites. Sensitivity analyses for most aspects of the post-emplacement systems models are included.

Analyzing indicator microorganisms, antibiotic resistant Escherichia coli, and regrowth potential of foodborne pathogens in various organic fertilizers.

PubMed

Miller, Cortney; Heringa, Spencer; Kim, Jinkyung; Jiang, Xiuping

2013-06-01

This study analyzed various organic fertilizers for indicator microorganisms, pathogens, and antibiotic-resistant Escherichia coli, and evaluated the growth potential of E. coli O157:H7 and Salmonella in fertilizers. A microbiological survey was conducted on 103 organic fertilizers from across the United States. Moisture content ranged from approximately 1% to 86.4%, and the average pH was 7.77. The total aerobic mesophiles ranged from approximately 3 to 9 log colony-forming units (CFU)/g. Enterobacteriaceae populations were in the range of <1 to approximately 7 log CFU/g, while coliform levels varied from <1 to approximately 6 log CFU/g. Thirty samples (29%) were positive for E. coli, with levels reaching approximately 6 log CFU/g. There were no confirmed positives for E. coli O157:H7, Salmonella, or Listeria monocytogenes. The majority of E. coli isolates (n=73), confirmed by glutamate decarboxylase (gad) PCR, were from group B1 (48%) and group A (32%). Resistance to 16 antibiotics was examined for 73 E. coli isolates, with 11 isolates having resistance to at least one antibiotic, 5 isolates to ≥ 2 antibiotics, and 2 isolates to ≥ 10 antibiotics. In the presence of high levels of background aerobic mesophiles, Salmonella and E. coli O157:H7 grew approximately 1 log CFU/g within 1 day of incubation in plant-based compost and fish emulsion-based compost, respectively. With low levels of background aerobic mesophiles, Salmonella grew approximately 2.6, 3.0, 3.0, and 3.2 log CFU/g in blood, bone, and feather meals and the mixed-source fertilizer, respectively, whereas E. coli O157:H7 grew approximately 4.6, 4.0, 4.0, and 4.8 log CFU/g, respectively. Our results revealed that the microbiological quality of organic fertilizers varies greatly, with some fertilizers containing antibiotic resistant E. coli and a few supporting the growth of foodborne pathogens after reintroduction into the fertilizer.

HIV Testing Patterns Among Urban YMSM of Color

PubMed Central

Leonard, Noelle R.; Ragan, Sonali; Gwadz, Marya V.; Aregbesola, Temi

2015-01-01

The heightened level of risk for HIV infection among African-American and Latino young men who have sex with men (YMSM) is driven by multi-level influences. Using cross-sectional data, we examined HIV testing patterns among urban YMSM of color in a high HIV sero-prevalence area (ages 16 to 21 years). Self-reported frequency of testing was high with 42% of youth reporting testing at a greater frequency than recommended guidelines. There were no differences between less frequent and high frequent testers on sexual risk behaviors. Most (80%) youth cited reassurance of HIV-negative status as a reason for testing. Further, over half of the sample reported numerous other reasons for HIV testing, which spanned individual, partner, social, and structural levels of influence. Approximately half of respondents indicated that peers, family members, and counselors influenced their motivation to get tested. Of concern, youths’ first HIV test occurred approximately two years after their first sexual experience with another male. These results indicate the need to consider developmental issues as well as for comprehensive, multi-level efforts to ensure that YMSM of color test at the CDC-recommended frequency, but not less than this or too frequently. PMID:24973260

Vibrational spectroscopy of water in hydrated lipid multi-bilayers. II. Two-dimensional infrared and peak shift observables within different theoretical approximations.

PubMed

Gruenbaum, Scott M; Pieniazek, Piotr A; Skinner, J L

2011-10-28

In a previous report, we calculated the infrared absorption spectrum and both the isotropic and anisotropic pump-probe signals for the OD stretch of isotopically dilute water in dilauroylphosphatidylcholine (DLPC) multi-bilayers as a function of the lipid hydration level. These results were then compared to recent experimental measurements and are in generally good agreement. In this paper, we will further investigate the structure and dynamics of hydration water using molecular dynamics simulations and calculations of the two-dimensional infrared and vibrational echo peak shift observables for hydration water in DLPC membranes. These observables have not yet been measured experimentally, but future comparisons may provide insight into spectral diffusion processes and hydration water heterogeneity. We find that at low hydration levels the motion of water molecules inside the lipid membrane is significantly arrested, resulting in very slow spectral diffusion. At higher hydration levels, spectral diffusion is more rapid, but still slower than in bulk water. We also investigate the effects of several common approximations on the calculation of spectroscopic observables by computing these observables within multiple levels of theory. The impact of these approximations on the resulting spectra affects our interpretation of these measurements and reveals that, for example, the cumulant approximation, which may be valid for certain systems, is not a good approximation for a highly heterogeneous environment such as hydration water in lipid multi-bilayers.

Nanometric depth resolution from multi-focal images in microscopy.

PubMed

Dalgarno, Heather I C; Dalgarno, Paul A; Dada, Adetunmise C; Towers, Catherine E; Gibson, Gavin J; Parton, Richard M; Davis, Ilan; Warburton, Richard J; Greenaway, Alan H

2011-07-06

We describe a method for tracking the position of small features in three dimensions from images recorded on a standard microscope with an inexpensive attachment between the microscope and the camera. The depth-measurement accuracy of this method is tested experimentally on a wide-field, inverted microscope and is shown to give approximately 8 nm depth resolution, over a specimen depth of approximately 6 µm, when using a 12-bit charge-coupled device (CCD) camera and very bright but unresolved particles. To assess low-flux limitations a theoretical model is used to derive an analytical expression for the minimum variance bound. The approximations used in the analytical treatment are tested using numerical simulations. It is concluded that approximately 14 nm depth resolution is achievable with flux levels available when tracking fluorescent sources in three dimensions in live-cell biology and that the method is suitable for three-dimensional photo-activated localization microscopy resolution. Sub-nanometre resolution could be achieved with photon-counting techniques at high flux levels.

Nanometric depth resolution from multi-focal images in microscopy

PubMed Central

Dalgarno, Heather I. C.; Dalgarno, Paul A.; Dada, Adetunmise C.; Towers, Catherine E.; Gibson, Gavin J.; Parton, Richard M.; Davis, Ilan; Warburton, Richard J.; Greenaway, Alan H.

2011-01-01

We describe a method for tracking the position of small features in three dimensions from images recorded on a standard microscope with an inexpensive attachment between the microscope and the camera. The depth-measurement accuracy of this method is tested experimentally on a wide-field, inverted microscope and is shown to give approximately 8 nm depth resolution, over a specimen depth of approximately 6 µm, when using a 12-bit charge-coupled device (CCD) camera and very bright but unresolved particles. To assess low-flux limitations a theoretical model is used to derive an analytical expression for the minimum variance bound. The approximations used in the analytical treatment are tested using numerical simulations. It is concluded that approximately 14 nm depth resolution is achievable with flux levels available when tracking fluorescent sources in three dimensions in live-cell biology and that the method is suitable for three-dimensional photo-activated localization microscopy resolution. Sub-nanometre resolution could be achieved with photon-counting techniques at high flux levels. PMID:21247948

A gauge-independent zeroth-order regular approximation to the exact relativistic Hamiltonian—Formulation and applications

NASA Astrophysics Data System (ADS)

Filatov, Michael; Cremer, Dieter

2005-01-01

A simple modification of the zeroth-order regular approximation (ZORA) in relativistic theory is suggested to suppress its erroneous gauge dependence to a high level of approximation. The method, coined gauge-independent ZORA (ZORA-GI), can be easily installed in any existing nonrelativistic quantum chemical package by programming simple one-electron matrix elements for the quasirelativistic Hamiltonian. Results of benchmark calculations obtained with ZORA-GI at the Hartree-Fock (HF) and second-order Møller-Plesset perturbation theory (MP2) level for dihalogens X2 (X=F,Cl,Br,I,At) are in good agreement with the results of four-component relativistic calculations (HF level) and experimental data (MP2 level). ZORA-GI calculations based on MP2 or coupled-cluster theory with single and double perturbations and a perturbative inclusion of triple excitations [CCSD(T)] lead to accurate atomization energies and molecular geometries for the tetroxides of group VIII elements. With ZORA-GI/CCSD(T), an improved estimate for the atomization energy of hassium (Z=108) tetroxide is obtained.

Equatorial Winds on Saturn and the Stratospheric Oscillation

NASA Technical Reports Server (NTRS)

Li, Liming; Jian, Xun; Ingersoll, Andrew P.; DelGenio, Anthony D.; Porco, Carolyn C.; West, Robert A.; Vasavada, Ashwin R.; Ewald, Shawn P.; Conrath, Barney J.; Gierasch, Peter J.;

First order sea-level cycles and supercontinent break up

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heller, P.L.; Angevine, C.L.

1985-01-01

The authors have developed a model that successfully predicts the approximate magnitude and timing of long term sea-level change without relying on short term increases in global spreading rates. The model involves the following key assumptions. (1) Ocean basins have two types of area/age distributions; Pacific ocean basins are rimmed by subduction zones and have triangular distributions; and Atlantic ocean basins which open at constant rates, have no subduction, and so have rectangular distributions. (2) The total area of the global ocean is constant so that the Pacific basin must close as the Atlantic opens. These assumptions approximate modern globalmore » ocean basin conditions. The model begins with supercontinent break up. As the Atlantic begins to open, the mean age of the global ocean decreases, the mean depth of the sea floor shallows, and sea level, therefore, rises. Once the Atlantic occupies more than 8 to 10% of the global ocean area, the mean age and depth of the ocean floor increases resulting in a sea-level fall. The model can be applied to the mid-Cretaceous sea-level high stand which followed break up of Pangea by 80 to 100 Ma. Based on average Atlantic opening rates, sea level rises to a peak of 44 m at 80 Ma after opening began and then falls by 84 m to the present. Thus the model is capable of explaining approximately half of the total magnitude of the post-mid-Cretaceous eustatic fall without invoking short-term changes in global spreading rates. In addition, the model predicts the observed time lag between supercontinent break up and sea-level high stand for both Mesozoic as well as early Paleozoic time.« less

Chance-constrained economic dispatch with renewable energy and storage

DOE PAGES

Cheng, Jianqiang; Chen, Richard Li-Yang; Najm, Habib N.; ...

2018-04-19

Increased penetration of renewables, along with uncertainties associated with them, have transformed how power systems are operated. High levels of uncertainty means that it is not longer possible to guarantee operational feasibility with certainty, instead constraints are required to be satisfied with high probability. We present a chance-constrained economic dispatch model that efficiently integrates energy storage and high renewable penetration to satisfy renewable portfolio requirements. Specifically, it is required that wind energy contributes at least a prespecified ratio of the total demand and that the scheduled wind energy is dispatchable with high probability. We develop an approximated partial sample averagemore » approximation (PSAA) framework to enable efficient solution of large-scale chanceconstrained economic dispatch problems. Computational experiments on the IEEE-24 bus system show that the proposed PSAA approach is more accurate, closer to the prescribed tolerance, and about 100 times faster than sample average approximation. Improved efficiency of our PSAA approach enables solution of WECC-240 system in minutes.« less

Chance-constrained economic dispatch with renewable energy and storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Jianqiang; Chen, Richard Li-Yang; Najm, Habib N.

Increased penetration of renewables, along with uncertainties associated with them, have transformed how power systems are operated. High levels of uncertainty means that it is not longer possible to guarantee operational feasibility with certainty, instead constraints are required to be satisfied with high probability. We present a chance-constrained economic dispatch model that efficiently integrates energy storage and high renewable penetration to satisfy renewable portfolio requirements. Specifically, it is required that wind energy contributes at least a prespecified ratio of the total demand and that the scheduled wind energy is dispatchable with high probability. We develop an approximated partial sample averagemore » approximation (PSAA) framework to enable efficient solution of large-scale chanceconstrained economic dispatch problems. Computational experiments on the IEEE-24 bus system show that the proposed PSAA approach is more accurate, closer to the prescribed tolerance, and about 100 times faster than sample average approximation. Improved efficiency of our PSAA approach enables solution of WECC-240 system in minutes.« less

An Excel sheet for inferring children's number-knower levels from give-N data.

PubMed

Negen, James; Sarnecka, Barbara W; Lee, Michael D

2012-03-01

Number-knower levels are a series of stages of number concept development in early childhood. A child's number-knower level is typically assessed using the give-N task. Although the task procedure has been highly refined, the standard ways of analyzing give-N data remain somewhat crude. Lee and Sarnecka (Cogn Sci 34:51-67, 2010, in press) have developed a Bayesian model of children's performance on the give-N task that allows knower level to be inferred in a more principled way. However, this model requires considerable expertise and computational effort to implement and apply to data. Here, we present an approximation to the model's inference that can be computed with Microsoft Excel. We demonstrate the accuracy of the approximation and provide instructions for its use. This makes the powerful inferential capabilities of the Bayesian model accessible to developmental researchers interested in estimating knower levels from give-N data.

Grandfather Tang Goes to High School

ERIC Educational Resources Information Center

Johnson, Iris DeLoach

2006-01-01

This article describes how the children's literature book, Grandfather Tang's Story, which is commonly used in the elementary grades, may be used at the high school level to engage students in an exploration of area and perimeter which includes basic operations with square roots, ordering numbers (decimal approximations, and their exact…

Incentives and other factors associated with employee participation in health risk assessments.

PubMed

Taitel, Michael S; Haufle, Vincent; Heck, Debi; Loeppke, Ronald; Fetterolf, Donald

2008-08-01

Investigate factors associated with employee participation rates in health risk assessments. This cross-sectional study using multiple regression analyzed data from 124 employers with 882,275 eligible employees who completed 344,825 health and productivity assessments (HPAs). Incentive value and Communications and Organizational Commitment Level (Com/Org Level) were the strongest predictors of HPA completion rates. Employer size and a Gateway Model were also significant predictors. In addition, a correlation of variables showed other important relationships. To achieve a 50% HPA completion rate, employers with a low Com/Org Level will need an incentive value of approximately $120 whereas employers with a high Com/Org Level only need approximately $40--a difference of $80 dollars. This applied study offers empirical evidence to help employers increase their employees' participation in health risk assessments.

Multi-level methods and approximating distribution functions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, D., E-mail: daniel.wilson@dtc.ox.ac.uk; Baker, R. E.

2016-07-15

Biochemical reaction networks are often modelled using discrete-state, continuous-time Markov chains. System statistics of these Markov chains usually cannot be calculated analytically and therefore estimates must be generated via simulation techniques. There is a well documented class of simulation techniques known as exact stochastic simulation algorithms, an example of which is Gillespie’s direct method. These algorithms often come with high computational costs, therefore approximate stochastic simulation algorithms such as the tau-leap method are used. However, in order to minimise the bias in the estimates generated using them, a relatively small value of tau is needed, rendering the computational costs comparablemore » to Gillespie’s direct method. The multi-level Monte Carlo method (Anderson and Higham, Multiscale Model. Simul. 10:146–179, 2012) provides a reduction in computational costs whilst minimising or even eliminating the bias in the estimates of system statistics. This is achieved by first crudely approximating required statistics with many sample paths of low accuracy. Then correction terms are added until a required level of accuracy is reached. Recent literature has primarily focussed on implementing the multi-level method efficiently to estimate a single system statistic. However, it is clearly also of interest to be able to approximate entire probability distributions of species counts. We present two novel methods that combine known techniques for distribution reconstruction with the multi-level method. We demonstrate the potential of our methods using a number of examples.« less

Middle atmosphere simulated with high vertical and horizontal resolution versions of a GCM: Improvements in the cold pole bias and generation of a QBO-like oscillation in the tropics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamilton, K.; Wilson, R.J.; Hemler, R.S.

1999-11-15

The large-scale circulation in the Geophysical Fluid Dynamics Laboratory SKYHI troposphere-stratosphere-mesosphere finite-difference general circulation model is examined as a function of vertical and horizontal resolution. The experiments examined include one with horizontal grid spacing of {approximately}35 km and another with {approximately}100 km horizontal grid spacing but very high vertical resolution (160 levels between the ground and about 85 km). The simulation of the middle-atmospheric zonal-mean winds and temperatures in the extratropics is found to be very sensitive to horizontal resolution. For example, in the early Southern Hemisphere winter the South Pole near 1 mb in the model is colder thanmore » observed, but the bias is reduced with improved horizontal resolution (from {approximately}70 C in a version with {approximately}300 km grid spacing to less than 10 C in the {approximately}35 km version). The extratropical simulation is found to be only slightly affected by enhancements of the vertical resolution. By contrast, the tropical middle-atmospheric simulation is extremely dependent on the vertical resolution employed. With level spacing in the lower stratosphere {approximately}1.5 km, the lower stratospheric zonal-mean zonal winds in the equatorial region are nearly constant in time. When the vertical resolution is doubled, the simulated stratospheric zonal winds exhibit a strong equatorially centered oscillation with downward propagation of the wind reversals and with formation of strong vertical shear layers. This appears to be a spontaneous internally generated oscillation and closely resembles the observed QBO in many respects, although the simulated oscillation has a period less than half that of the real QBO.« less

Passive radiation shielding considerations for the proposed space elevator

NASA Astrophysics Data System (ADS)

Jorgensen, A. M.; Patamia, S. E.; Gassend, B.

2007-02-01

The Earth's natural van Allen radiation belts present a serious hazard to space travel in general, and to travel on the space elevator in particular. The average radiation level is sufficiently high that it can cause radiation sickness, and perhaps death, for humans spending more than a brief period of time in the belts without shielding. The exact dose and the level of the related hazard depends on the type or radiation, the intensity of the radiation, the length of exposure, and on any shielding introduced. For the space elevator the radiation concern is particularly critical since it passes through the most intense regions of the radiation belts. The only humans who have ever traveled through the radiation belts have been the Apollo astronauts. They received radiation doses up to approximately 1 rem over a time interval less than an hour. A vehicle climbing the space elevator travels approximately 200 times slower than the moon rockets did, which would result in an extremely high dose up to approximately 200 rem under similar conditions, in a timespan of a few days. Technological systems on the space elevator, which spend prolonged periods of time in the radiation belts, may also be affected by the high radiation levels. In this paper we will give an overview of the radiation belts in terms relevant to space elevator studies. We will then compute the expected radiation doses, and evaluate the required level of shielding. We concentrate on passive shielding using aluminum, but also look briefly at active shielding using magnetic fields. We also look at the effect of moving the space elevator anchor point and increasing the speed of the climber. Each of these mitigation mechanisms will result in a performance decrease, cost increase, and technical complications for the space elevator.

Office workers' computer use patterns are associated with workplace stressors.

PubMed

Eijckelhof, Belinda H W; Huysmans, Maaike A; Blatter, Birgitte M; Leider, Priscilla C; Johnson, Peter W; van Dieën, Jaap H; Dennerlein, Jack T; van der Beek, Allard J

2014-11-01

This field study examined associations between workplace stressors and office workers' computer use patterns. We collected keyboard and mouse activities of 93 office workers (68F, 25M) for approximately two work weeks. Linear regression analyses examined the associations between self-reported effort, reward, overcommitment, and perceived stress and software-recorded computer use duration, number of short and long computer breaks, and pace of input device usage. Daily duration of computer use was, on average, 30 min longer for workers with high compared to low levels of overcommitment and perceived stress. The number of short computer breaks (30 s-5 min long) was approximately 20% lower for those with high compared to low effort and for those with low compared to high reward. These outcomes support the hypothesis that office workers' computer use patterns vary across individuals with different levels of workplace stressors. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Computational model for operation of 2 mum co-doped Tm,Ho solid state lasers.

PubMed

Louchev, Oleg A; Urata, Yoshiharu; Saito, Norihito; Wada, Satoshi

2007-09-17

A computational model for operation of co-doped Tm,Ho solid-state lasers is developed coupling (i) 8-level rate equations with (ii) TEM00 laser beam distribution, and (iii) complex heat dissipation model. Simulations done for Q-switched approximately 0.1 J giant pulse generation by Tm,Ho:YLF laser show that approximately 43% of the 785 nm light diode side-pumped energy is directly transformed into the heat inside the crystal, whereas approximately 45% is the spontaneously emitted radiation from (3)F(4), (5)I(7) , (3)H(4) and (3)H(5) levels. In water-cooled operation this radiation is absorbed inside the thermal boundary layer where the heat transfer is dominated by heat conduction. In high-power operation the resulting temperature increase is shown to lead to (i) significant decrease in giant pulse energy and (ii) thermal lensing.

The Search for Specialists and Managers. Staff Shortage in Germany.

ERIC Educational Resources Information Center

Stahl, Klaus, Ed.

1999-01-01

Despite its high unemployment level, Germany is experiencing a shortage of specialists and managers. Germany's need for highly qualified information technology (IT) workers and engineers is particularly great. Approximately 10,000 posts for computer scientists and IT specialists remained vacant in 1998. Because of the shortage of such specialists,…

Low ozone over Southern Australia in August 2011 and its impact on solar ultraviolet radiation levels.

PubMed

Gies, Peter; Klekociuk, Andrew; Tully, Matthew; Henderson, Stuart; Javorniczky, John; King, Kerryn; Lemus-Deschamps, Lilia; Makin, Jennifer

2013-01-01

During August 2011 stratospheric ozone over much of Southern Australia dropped to very low levels (approximately 265 Dobson Units) for over a week above major population centers. The weather during this low ozone period was mostly clear and sunny, resulting in measured solar ultraviolet radiation (UVR) levels up to 40% higher than normal, with UV Index > 3 despite being winter. Satellite ozone measurements and meteorological assimilated data indicate that the event was likely due in large part to the anomalous southward movement over Australia of ozone-poor air in the lower stratosphere originating from tropical latitudes. At the time, a study measuring the UVR exposures of outdoor workers in Victoria was underway and a number of the workers recorded substantial UVR exposures and were sunburnt. Given the cities and populations involved (approximately 10 million people), it is likely that many people could have been exposed to anomalously high levels of solar UVR for that time of year, with resultant higher UVR exposures and sunburns to unacclimatized skin (often a problem transitioning from low winter to higher spring UVR levels). Reporting procedures have been modified to utilize ozone forecasts to warn the public of anomalously high UVR levels in the future. © 2013 The American Society of Photobiology and Commonwealth of Australia.

Development of high protein, high fiber smoothie as a grab-and-go breakfast option using response surface methodology.

PubMed

Mehta, Dipakkumar; Kumar, M H Sathish; Sabikhi, Latha

2017-11-01

The current work aimed to formulate smoothie by optimizing varying levels of soy protein isolate (1.5-2.5% w/w), sucralose (150-190 ppm) and pectin (0.3-0.5% w/w) along with milk, legume (chickpea), vegetable (carrot), fruit (mango), honey and trisodium citrate by response surface methodology on the basis of sensory (color and appearance, flavor, consistency, sweetness and overall acceptability) and physical (expressible serum and viscosity) responses. Soy protein isolate and pectin levels influenced color and appearance, flavor, consistency and overall acceptability significantly. Soy protein isolate and pectin showed a positive correlation with viscosity of smoothie with reduced expressible serum. Smoothie was optimized with 1.8% (w/w) soy protein isolate, 166.8 ppm sucralose, and 0.5% (w/w) pectin with acceptable quality. One serving (325 ml) of optimized smoothie provides approximately 23% protein, 27% dietary fiber of the recommended daily values and provides approximately 74 kcal per 100 ml of smoothie, which renders smoothie as a high protein, high fiber, grab-and-go breakfast option.

Conceptual Design of a 50--100 MW Electron Beam Accelerator System for the National Hypersonic Wind Tunnel Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

SCHNEIDER,LARRY X.

2000-06-01

The National Hypersonic Wind Tunnel program requires an unprecedented electron beam source capable of 1--2 MeV at a beam power level of 50--100 MW. Direct-current electron accelerator technology can readily generate high average power beams to approximately 5 MeV at output efficiencies greater than 90%. However, due to the nature of research and industrial applications, there has never been a requirement for a single module with an output power exceeding approximately 500 kW. Although a 50--100 MW module is a two-order extrapolation from demonstrated power levels, the scaling of accelerator components appears reasonable. This paper presents an evaluation of componentmore » and system issues involved in the design of a 50--100 MW electron beam accelerator system with precision beam transport into a high pressure flowing air environment.« less

Rapid perceptual adaptation to high gravitoinertial force levels Evidence for context-specific adaptation

NASA Technical Reports Server (NTRS)

Lackner, J. R.; Graybiel, A.

1982-01-01

Subjects exposed to periodic variations in gravitoinertial force (2-G peak) in parabolic flight maneuvers quickly come to perceive the peak force level as having decreased in intensity. By the end of a 40-parabola flight, the decrease in apparent force is approximately 40%. On successive flight days, the apparent intensity of the force loads seems to decrease as well, indicating a cumulative adaptive effect. None of the subjects reported feeling abnormally 'light' for more than a minute or two after return to 1-G background force levels. The pattern of findings suggests a context-specific adaptation to high-force levels.

Energy Spectra, Composition, and Other Properties of Ground-Level Events During Solar Cycle 23

NASA Technical Reports Server (NTRS)

Mewaldt, R. A.; COhen, C. M. S.; Labrador, A. W.; Leske, R. A.; Looper, M. D.; Haggerty, D. K.; Mason, G. M.; Mazur, J. E.; vonRosenvinge, T. T.

2012-01-01

We report spacecraft measurements of the energy spectra of solar protons and other solar energetic particle properties during the 16 Ground Level Events (GLEs) of Solar Cycle 23. The measurements were made by eight instruments on the ACE, GOES, SAMPBX, and STEREO spacecraft and extend from approximately 0.1 to approximately 500-700 MeV. All of the proton spectra exhibit spectral breaks at energies ranging from approximately 2 to approximately 46 MeV and all are well fit by a double power-law shape. A comparison of GLE events with a larger sample of other solar energetic particle (SEP) events shows that the typical spectral indices are harder in GLE events, with a mean slope of -3.18 at greater than 40 MeV/nuc. In the energy range 45 to 80 MeV/nucleon about approximately 50% of GLE events have properties in common with impulsive He-3-rich SEP events, including enrichments in Ne/O, Fe/O, Ne-22/Ne-20, and elevated mean charge states of Fe. These He-3 rich events contribute to the seed population accelerated by CME-driven shocks. An analysis is presented of whether highly-ionized Fe ions observed in five events could be due to electron stripping during shock acceleration in the low corona. Making use of stripping calculations by others and a coronal density model, we can account for events with mean Fe charge states of (Q(sub Fe) is approximately equal to +20 if the acceleration starts at approximately 1.24-1.6 solar radii, consistent with recent comparisons of CME trajectories and type-II radio bursts. In addition, we suggest that gradual stripping of remnant ions from earlier large SEP events may also contribute a highly-ionized suprathermal seed population. We also discuss how observed SEP spectral slopes relate to the energetics of particle acceleration in GLE and other large SEP events.

Improvement of FK506 Production in the High-Yielding Strain Streptomyces sp. RM7011 by Engineering the Supply of Allylmalonyl-CoA Through a Combination of Genetic and Chemical Approach.

PubMed

Mo, SangJoon; Lee, Sung-Kwon; Jin, Ying-Yu; Suh, Joo-Won

2016-02-01

FK506, a widely used immunosuppressant, is a 23-membered polyketide macrolide that is produced by several Streptomyces species. FK506 high-yielding strain Streptomyces sp. RM7011 was developed from the discovered Streptomyces sp. KCCM 11116P by random mutagenesis in our previous study. The results of transcript expression analysis showed that the transcription levels of tcsA, B, C, and D were increased in Streptomyces sp. RM7011 by 2.1-, 3.1-, 3.3-, and 4.1- fold, respectively, compared with Streptomyces sp. KCCM 11116P. The overexpression of tcsABCD genes in Streptomyces sp. RM7011 gave rise to approximately 2.5-fold (238.1 μg/ml) increase in the level of FK506 production compared with that of Streptomyces sp. RM7011. When vinyl pentanoate was added into the culture broth of Streptomyces sp. RM7011, the level of FK506 production was approximately 2.2-fold (207.7 μg/ml) higher than that of the unsupplemented fermentation. Furthermore, supplementing the culture broth of Streptomyces sp. RM7011 expressing tcsABCD genes with vinyl pentanoate resulted in an additional 1.7-fold improvement in the FK506 titer (498.1 μg/ml) compared with that observed under nonsupplemented condition. Overall, the level of FK506 production was increased approximately 5.2-fold by engineering the supply of allylmalonyl-CoA in the high-yielding strain Streptomyces sp. RM7011, using a combination of overexpressing tcsABCD genes and adding vinyl pentanoate, as compared with Streptomyces sp. RM7011 (95.3 μg/ml). Moreover, among the three precursors analyzed, pentanoate was the most effective precursor, supporting the highest titer of FK506 in the FK506 high-yielding strain Streptomyces sp. RM7011.

Decreased content of protein 4.2 in ankyrin-deficient normoblastosis (nb/nb) mouse red blood cells: evidence for ankyrin enhancement of protein 4.2 membrane binding.

PubMed

Rybicki, A C; Musto, S; Schwartz, R S

1995-11-01

Homozygous normoblastosis (nb/nb) mice, whose red blood cell (RBC) membranes are nearly completely deficient in full-length 210-kD ankyrin, were used to study interactions between ankyrin and protein 4.2 (P4.2). Although it is unclear whether or not these proteins interact in the membrane, both ankyrin and P4.2 bind to the cytoplasmic domain of band 3 (cdb3). In addition to the complete deficiency of full-length ankyrin, nb/nb RBC membranes are also partially spectrin deficient, resulting in morphologically spherocytic and mechanically fragile cells. A new finding was that nb/nb RBC membranes are severely (approximately 73%) P4.2 deficient compared with wild type (+/+) or high reticulocyte mouse RBC membranes. Metabolic labeling of nb/nb reticulocytes showed active P4.2 synthesis at levels comparable with high reticulocyte controls suggesting that the nb/nb P4.2 deficiency was not the result of defective P4.2 synthesis. Reconstitution of nb/nb inside-out vesicles (IOVs) with human RBC ankyrin restored ankyrin levels to approximately 80% of +/+ IOV levels and increased binding of exogenously added human RBC P4.2 by approximately 60%. These results suggest that ankyrin is required for normal associations of P4.2 with the RBC membrane.

Lead paint removal with high-intensity light pulses.

PubMed

Grapperhaus, Michael J; Schaefer, Raymond B

2006-12-15

This paper presents the results of an initial investigation into using high-intensity incoherent light pulses to strip paint. Measurements of light pulse characteristics, the reflectivity of different paints and initial experiments on the threshold for paint removal, and paint removal are presented, along with an approximate model consistent with experimental results. Paint removal tests include lead paint, the reduction of lead levels to below levels required for lead abatement, as well as air and light emissions measurements that are within regulatory guidelines.

Wind Speed Dependence of Acoustic Ambient Vertical Directional Spectra at High Frequency

DTIC Science & Technology

1989-05-26

the measurements, which is 8 to 32 kHz, is sufficiently high that the propagation is adequately modeled using the Eikonal equation approximation. 4 TD...level spectra were calculated from the resulting time series. Spectral levels at 8, 16, and 32 kHz were recorded in a database along with the wind...indications of biological or industrial contaminations were removed. The resulting database seen here contained 215 samples. 10 * TD 8565 0z 00 a.I. cn

Effective hepatocyte transplantation using rat hepatocytes with low asialoglycoprotein receptor expression.

PubMed

Ise, Hirohiko; Nikaido, Toshio; Negishi, Naoki; Sugihara, Nobuhiro; Suzuki, Fumitaka; Akaike, Toshihiro; Ikeda, Uichi

2004-08-01

Development of a reliable method of isolating highly proliferative potential hepatocytes provides information crucial to progress in the field of hepatocyte transplantation. The aim of this study was to develop reliable hepatocyte transplantation using highly proliferative, eg, progenitor-like hepatocytes, based on asialoglycoprotein receptor (ASGPR) expression levels for hepatocyte transplantation. We have previously reported that mouse hepatocytes with low ASGPR expression levels have highly proliferative potential and can be used as progenitor-like hepatocytes. We therefore fractionated F344 male rat hepatocytes expressing low and high levels of ASGPR and determined the liver repopulation capacity of hepatocytes according to low and high ASGPR expression in the liver. Next, 2 x 10(5) cells of each type were transplanted into female liver regenerative model dipeptidyl peptidase-deficient rats, and we estimated the rate of liver repopulation by the transplanted hepatocytes in the host liver, as determined by recognition of the Sry gene on the Y-chromosome. At 60 days after hepatocyte transplantation, the transplanted hepatocytes occupied approximately 76% of the total hepatocyte mass in the case of the transplantation of hepatocytes with low ASGPR expression, but accounted for approximately 12% and 17% of the mass in the case of the transplantation of hepatocytes with high ASGPR expression and unfractionated hepatocytes, respectively. In conclusion, these findings suggest that hepatocytes with low ASGPR expression can result in normal liver function and a high repopulation capacity in vivo. These results provide insight into development of a strategy for effective liver repopulation using transplanted hepatocytes.

The effects of the catalytic converter and fuel sulfur level on motor vehicle particulate matter emissions: light duty diesel vehicles.

PubMed

Maricq, M Matti; Chase, Richard E; Xu, Ning; Laing, Paul M

2002-01-15

Wind tunnel measurements and direct tailpipe particulate matter (PM) sampling are utilized to examine how the combination of oxidation catalyst and fuel sulfur content affects the nature and quantity of PM emissions from the exhaust of a light duty diesel truck. When low sulfur fuel (4 ppm) is used, or when high sulfur (350 ppm)fuel is employed without an active catalyst present, a single log-normal distribution of exhaust particles is observed with a number mean diameter in the range of 70-83 nm. In the absence of the oxidation catalyst, the high sulfur level has at most a modest effect on particle emissions (<50%) and a minor effect on particle size (<5%). In combination with the active oxidation catalyst tested, high sulfur fuel can lead to a second, nanoparticle, mode, which appears at approximately 20 nm during high speed operation (70 mph), but is not present at low speed (40 mph). A thermodenuder significantly reduces the nanoparticle mode when set to temperatures above approximately 200 degrees C, suggesting that these particles are semivolatile in nature. Because they are observed only when the catalyst is present and the sulfur level is high, this mode likely originates from the nucleation of sulfates formed over the catalyst, although the composition may also include hydrocarbons.

High-resolution absorption measurements of NH3 at high temperatures: 500-2100 cm-1

NASA Astrophysics Data System (ADS)

Barton, Emma J.; Yurchenko, Sergei N.; Tennyson, Jonathan; Clausen, Sønnik; Fateev, Alexander

2015-12-01

High-resolution absorption spectra of NH3 in the region 500-2100 cm-1 at temperatures up to 1027 °C and approximately atmospheric pressure (1013±20 mbar) are measured. NH3 concentrations of 1000 ppm, 0.5% and 1% in volume fraction were used in the measurements. Spectra are recorded in high temperature gas flow cells using a Fourier Transform Infrared (FTIR) spectrometer at a nominal resolution of 0.09 cm-1. Measurements at 22.7 °C are compared to high-resolution cross sections available from the Pacific Northwest National Laboratory (PNNL). The higher temperature spectra are analysed by comparison to a variational line list, BYTe, and experimental energy levels determined using the MARVEL procedure. Approximately 2000 lines have been assigned, of which 851 are newly assigned to mainly hot bands involving vibrational states as high as v2=5.

Synchronization of low- and high-threshold motor units.

PubMed

Defreitas, Jason M; Beck, Travis W; Ye, Xin; Stock, Matt S

2014-04-01

We examined the degree of synchronization for both low- and high-threshold motor unit (MU) pairs at high force levels. MU spike trains were recorded from the quadriceps during high-force isometric leg extensions. Short-term synchronization (between -6 and 6 ms) was calculated for every unique MU pair for each contraction. At high force levels, earlier recruited motor unit pairs (low-threshold) demonstrated relatively low levels of short-term synchronization (approximately 7.3% extra firings than would have been expected by chance). However, the magnitude of synchronization increased significantly and linearly with mean recruitment threshold (reaching 22.1% extra firings for motor unit pairs recruited above 70% MVC). Three potential mechanisms that could explain the observed differences in synchronization across motor unit types are proposed and discussed. Copyright © 2013 Wiley Periodicals, Inc.

A frozen Gaussian approximation-based multi-level particle swarm optimization for seismic inversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jinglai, E-mail: jinglaili@sjtu.edu.cn; Lin, Guang, E-mail: lin491@purdue.edu; Computational Sciences and Mathematics Division, Pacific Northwest National Laboratory, Richland, WA 99352

2015-09-01

In this paper, we propose a frozen Gaussian approximation (FGA)-based multi-level particle swarm optimization (MLPSO) method for seismic inversion of high-frequency wave data. The method addresses two challenges in it: First, the optimization problem is highly non-convex, which makes hard for gradient-based methods to reach global minima. This is tackled by MLPSO which can escape from undesired local minima. Second, the character of high-frequency of seismic waves requires a large number of grid points in direct computational methods, and thus renders an extremely high computational demand on the simulation of each sample in MLPSO. We overcome this difficulty by threemore » steps: First, we use FGA to compute high-frequency wave propagation based on asymptotic analysis on phase plane; Then we design a constrained full waveform inversion problem to prevent the optimization search getting into regions of velocity where FGA is not accurate; Last, we solve the constrained optimization problem by MLPSO that employs FGA solvers with different fidelity. The performance of the proposed method is demonstrated by a two-dimensional full-waveform inversion example of the smoothed Marmousi model.« less

Numerical Boundary Conditions for Specular Reflection in a Level-Sets-Based Wavefront Propagation Method

DTIC Science & Technology

2012-12-01

acoustics One begins with Eikonal equation for the acoustic phase function S(t,x) as derived from the geometric acoustics (high frequency) approximation to...zb(x) is smooth and reasonably approximated as piecewise linear. The time domain ray (characteristic) equations for the Eikonal equation are ẋ(t)= c...travel time is affected, which is more physically relevant than global error in φ since it provides the phase information for the Eikonal equation (2.1

Hsc66 and Hsc20, a new heat shock cognate molecular chaperone system from Escherichia coli.

PubMed

Vickery, L E; Silberg, J J; Ta, D T

1997-05-01

The hscA and hscB genes of Escherichia coli encode novel chaperone and co-chaperone proteins, designated Hsc66 and Hsc20, respectively. We have overproduced and purified Hsc66 and Hsc20 in high yield in E. coli and describe their initial characterization including absorbance, fluorescence, and circular dichroism spectra. Immunoblot analyses of E. coli cultures using antisera to Hsc66 and Hsc20 raised in rabbits establish that Hsc66 and Hsc20 are constitutively expressed at levels corresponding to cell concentration approximately 20 microM and approximately 10 microM, respectively. The levels do not change appreciably following heat shock (44 degrees C), but a small increase in Hsc20 is observed following a shift to 10 degrees C. Purified Hsc66 exhibits a low intrinsic ATPase activity (approximately 0.6 min-1 at 37 degrees C), and Hsc20 was found to stimulate this activity up to 3.8-fold with half-maximal stimulation at a concentration approximately 5 microM. These findings suggest that Hsc66 and Hsc20 comprise a molecular chaperone system similar to the prokaryotic DnaK/DnaJ and eukaryotic hsp70/hsp40 systems. Sequence differences between Hsc66 and Hsc20 compared to other members of this chaperone family, however, suggest that the Hsc66/Hsc20 system will display different peptide binding specificity and that it is likely to be subject to different regulatory mechanisms. The high level of constitutive expression and the lack of a major response to temperature changes suggest that Hsc66 and Hsc20 play an important cellular role(s) under non-stress conditions.

Hsc66 and Hsc20, a new heat shock cognate molecular chaperone system from Escherichia coli.

PubMed Central

Vickery, L. E.; Silberg, J. J.; Ta, D. T.

1997-01-01

The hscA and hscB genes of Escherichia coli encode novel chaperone and co-chaperone proteins, designated Hsc66 and Hsc20, respectively. We have overproduced and purified Hsc66 and Hsc20 in high yield in E. coli and describe their initial characterization including absorbance, fluorescence, and circular dichroism spectra. Immunoblot analyses of E. coli cultures using antisera to Hsc66 and Hsc20 raised in rabbits establish that Hsc66 and Hsc20 are constitutively expressed at levels corresponding to cell concentration approximately 20 microM and approximately 10 microM, respectively. The levels do not change appreciably following heat shock (44 degrees C), but a small increase in Hsc20 is observed following a shift to 10 degrees C. Purified Hsc66 exhibits a low intrinsic ATPase activity (approximately 0.6 min-1 at 37 degrees C), and Hsc20 was found to stimulate this activity up to 3.8-fold with half-maximal stimulation at a concentration approximately 5 microM. These findings suggest that Hsc66 and Hsc20 comprise a molecular chaperone system similar to the prokaryotic DnaK/DnaJ and eukaryotic hsp70/hsp40 systems. Sequence differences between Hsc66 and Hsc20 compared to other members of this chaperone family, however, suggest that the Hsc66/Hsc20 system will display different peptide binding specificity and that it is likely to be subject to different regulatory mechanisms. The high level of constitutive expression and the lack of a major response to temperature changes suggest that Hsc66 and Hsc20 play an important cellular role(s) under non-stress conditions. PMID:9144776

The Anisotropy of the Microwave Background to l=3500: Mosaic Observations with the Cosmic Background Imager

NASA Technical Reports Server (NTRS)

Pearson, T. J.; Mason, B. S.; Readhead, A. C. S.; Shepherd, M. C.; Sievers, J. L.; Udomprasert, P. S.; Cartwright, J. K.; Farmer, A. J.; Padin, S.; Myers, S. T.;

Streptococcus mutans levels and caries prevalence in low-income schoolchildren.

PubMed

Seibert, Wilda; Farmer-Dixon, Cherae; Bolden, Theodore; Stewart, James H

2002-01-01

Previous studies have shown that persons having high Streptococcus mutans levels in the saliva are "at risk" for dental caries. Most investigators agree, that if high levels of S. mutans were identified early in the life of at-risk children, dental decay could be reduced or eliminated through intervention. The purpose of this study is to show an association between S. mutans levels and caries prevalence in a sample of elementary school children. The study group consisted of 242 school children, ages 5-13 years. The subjects were divided into two age groups, 5-8 years and 9-13 years. Approximately 59 percent were African Americans. The sample of 242 children were equally females and males, 50 percent in each group. The Dentocult SM Test was used to make S. mutans determinations. The df-t index was used to determine the number of decayed and filled teeth of children ages 5-8 years; the DMF-T Index estimated the number of decayed, missing or filled teeth of children ages 9-13 years. Dental caries were found in 58 percent of the children (mean = 2.67, and range of 1-11). Approximately 47 percent of the children with caries had high S. mutans levels (100K-1M). Females had higher S. mutans levels than males in the 9-13 age group, p < .05. Analysis of Variance Test indicated that S. mutans levels for older females (ages 9-13) were significantly higher than those observed in males the same age (p < .01). This trend was not observed in younger children, ages 5-8 years. In addition, no significant difference or interaction was noted by sex for S. mutans levels and decayed or filled teeth (df-t) for younger children. We conclude that high levels of Streptococcus mutans are related to increased number of decayed teeth and conversely, low Streptococcus mutans levels are related to fewer dental caries. This study was supported in part by Colgate-Palmolive Company and the National Dental Association Foundation, Inc.

Silicon Carbide Radioisotope Batteries

NASA Technical Reports Server (NTRS)

Rybicki, George C.

2005-01-01

The substantial radiation resistance and large bandgap of SiC semiconductor materials makes them an attractive candidate for application in a high efficiency, long life radioisotope battery. To evaluate their potential in this application, simulated batteries were constructed using SiC diodes and the alpha particle emitter Americium Am-241 or the beta particle emitter Promethium Pm-147. The Am-241 based battery showed high initial power output and an initial conversion efficiency of approximately 16%, but the power output decayed 52% in 500 hours due to radiation damage. In contrast the Pm-147 based battery showed a similar power output level and an initial conversion efficiency of approximately 0.6%, but no degradation was observed in 500 hours. However, the Pm-147 battery required approximately 1000 times the particle fluence as the Am-242 battery to achieve a similar power output. The advantages and disadvantages of each type of battery and suggestions for future improvements will be discussed.

Self-assembled nanogels of cholesteryl-modified polysaccharides: effect of the polysaccharide structure on their association characteristics in the dilute and semidilute regimes.

PubMed

Akiyama, Eri; Morimoto, Nobuyuki; Kujawa, Piotr; Ozawa, Yayoi; Winnik, Françoise M; Akiyoshi, Kazunari

2007-08-01

The assembly of cholesteryl derivatives of the highly branched polysaccharide mannan Mw = (5.2 x 104 g/mol) in dilute aqueous solution was investigated by 1H nuclear magnetic resonance (NMR) spectroscopy, size-exclusion chromatography coupled with multiangle laser scattering (SEC-MALLS), dynamic light scattering (DLS), atomic force microscopy (AFM), fluorescence quenching, and fluorescence depolarization measurements. In the dilute regime, cholesteryl-bearing mannans (CHM) containing approximately 1 cholesteryl group per 100 mannopyranose units formed nanogels with a hydrodynamic radius (RH) of approximately 20 nm containing approximately 8 macromolecules held together via hydrophobic nanodomains consisting of approximately 9 cholesteryl groups. Their density Phih ( approximately 0.02) was significantly lower than the density ( approximately 0.16) of nanogels formed by a cholesteryl derivative of the linear polysaccharide pullulan (CHP) of identical molar mass and level of cholesteryl substitution. In the semidilute regime, CHM nanogels formed a macrogel network for concentrations higher than 12.5% w/w, whereas CHP nanogels underwent macrogelation only above a threshold concentration of 8.0% w/w, as revealed by oscillatory and steady-shear viscosity measurements. The differences in the solution properties of CHM and CHP reflect differences in their assembly on the molecular level, in particular, the size and number of hydrophobic nanodomains and the hydration level. They are attributed to differences in the mobility of the cholesteryl groups which, itself, can be traced to the fact that in CHM the cholesteryl groups are predominantly linked to short oligomannopyranose branches, whereas in CHP they are linked to the polymer main chain. Our study provides a novel means to nanoengineer polysaccharide nanogels which may find unique biotechnological applications.

Mapping disease at an approximated individual level using aggregate data: a case study of mapping New Hampshire birth defects.

PubMed

Shi, Xun; Miller, Stephanie; Mwenda, Kevin; Onda, Akikazu; Reese, Judy; Onega, Tracy; Gui, Jiang; Karagas, Margret; Demidenko, Eugene; Moeschler, John

2013-09-06

Limited by data availability, most disease maps in the literature are for relatively large and subjectively-defined areal units, which are subject to problems associated with polygon maps. High resolution maps based on objective spatial units are needed to more precisely detect associations between disease and environmental factors. We propose to use a Restricted and Controlled Monte Carlo (RCMC) process to disaggregate polygon-level location data to achieve mapping aggregate data at an approximated individual level. RCMC assigns a random point location to a polygon-level location, in which the randomization is restricted by the polygon and controlled by the background (e.g., population at risk). RCMC allows analytical processes designed for individual data to be applied, and generates high-resolution raster maps. We applied RCMC to the town-level birth defect data for New Hampshire and generated raster maps at the resolution of 100 m. Besides the map of significance of birth defect risk represented by p-value, the output also includes a map of spatial uncertainty and a map of hot spots. RCMC is an effective method to disaggregate aggregate data. An RCMC-based disease mapping maximizes the use of available spatial information, and explicitly estimates the spatial uncertainty resulting from aggregation.

Increased serum and testicular androgen levels in F1 rats with lifetime exposure to soy isoflavones.

PubMed

McVey, Mark J; Cooke, Gerard M; Curran, Ivan H A

2004-07-01

The consequences of dietary soy isoflavones on serum and testicular androgen levels were examined in F1 male rats from a multigeneration study investigating the effects of diets varying in isoflavone content. Rats were fed either a soy-free casein based diet (AIN93G) or a diet in which alcohol-washed soy protein replaced casein as the protein source and to which increasing amounts of Novasoy, a commercially available isoflavone supplement were added. Analysis of these diets showed that the isoflavone content in each diet was 0 (diet 1; casein based control), 31.7 (diet 2; alcohol-washed soy-based diet control), 36.1 (diet 3), 74.5 (diet 4), 235.6 (diet 5) and 1046.6 (diet 6) mg total isoflavones/kg pelleted diet. The levels of isoflavones in diet 1 would represent a daily intake level of 0 mg isoflavones, diets 2 and 3 estimate a low soy-containing human diet (e.g. North American), diet 4 would correspond to Asian diets (e.g. Japanese) or adult humans taking isoflavone supplements, diet 5 approximates the isoflavone intake by babies fed soy based infant formula and diet 6 approximates fivefold the intake levels by babies or 10-fold the intake levels of adults consuming high isoflavone containing diets. Serum testosterone (T) from F1 male rats sacrificed on postnatal days (PND) 28, 70, 120, 240 and 360 were low at PND 28 (0.4 ng/ml), increased approximately five to sixfold at PND 70 (2.5-3.0 ng/ml) and thereafter declined to a steady state level of approximately 1 ng/ml by PND 120. However, rats on diets 5 and 6 demonstrated altered serum testosterone profiles such that at days 120, testosterone levels remained significantly elevated at approximately 3 ng/ml (P < 0.05). Serum dihydrotestosterone levels exhibited similar profiles and the levels in PND 120 rats on diet 5 or 6 were also significantly elevated (two to threefold, P < 0.05). The intra-testicular testosterone concentration in rats on diet 5 was also elevated at PND 120 compared with diet 1 (P < 0.05). These findings show that F1 male rats continuously exposed to a mixture of dietary soy isoflavones from conception onwards exhibit altered serum and testicular androgen profiles.

Cumulative neighborhood risk of psychosocial stress and allostatic load in adolescents.

PubMed

Theall, Katherine P; Drury, Stacy S; Shirtcliff, Elizabeth A

2012-10-01

The authors examined the impact of cumulative neighborhood risk of psychosocial stress on allostatic load (AL) among adolescents as a mechanism through which life stress, including neighborhood conditions, may affect health and health inequities. They conducted multilevel analyses, weighted for sampling and propensity score-matched, among adolescents aged 12-20 years in the National Health and Nutrition Examination Survey (1999-2006). Individuals (first level, n = 11,886) were nested within families/households (second level, n = 6,696) and then census tracts (third level, n = 2,191) for examination of the contextual effect of cumulative neighborhood risk environment on AL. Approximately 35% of adolescents had 2 or more biomarkers of AL. A significant amount of variance in AL was explained at the neighborhood level. The likelihood of having a high AL was approximately 10% higher for adolescents living in medium-cumulative-risk neighborhoods (adjusted odds ratio (OR) = 1.09, 95% confidence interval (CI): 1.08, 1.09), 28% higher for those living in high-risk neighborhoods (adjusted OR = 1.28, 95% CI: 1.27, 1.30), and 69% higher for those living in very-high-risk neighborhoods (adjusted OR = 1.69, 95% CI: 1.68, 1.70) as compared with adolescents living in low-risk areas. Effect modification was observed by both individual- and neighborhood-level sociodemographic factors. These findings offer support for the hypothesis that neighborhood risks may culminate in a range of biologically mediated negative health outcomes detectable in adolescents.

Cumulative Neighborhood Risk of Psychosocial Stress and Allostatic Load in Adolescents

PubMed Central

Theall, Katherine P.; Drury, Stacy S.; Shirtcliff, Elizabeth A.

2012-01-01

The authors examined the impact of cumulative neighborhood risk of psychosocial stress on allostatic load (AL) among adolescents as a mechanism through which life stress, including neighborhood conditions, may affect health and health inequities. They conducted multilevel analyses, weighted for sampling and propensity score-matched, among adolescents aged 12–20 years in the National Health and Nutrition Examination Survey (1999–2006). Individuals (first level, n = 11,886) were nested within families/households (second level, n = 6,696) and then census tracts (third level, n = 2,191) for examination of the contextual effect of cumulative neighborhood risk environment on AL. Approximately 35% of adolescents had 2 or more biomarkers of AL. A significant amount of variance in AL was explained at the neighborhood level. The likelihood of having a high AL was approximately 10% higher for adolescents living in medium-cumulative-risk neighborhoods (adjusted odds ratio (OR) = 1.09, 95% confidence interval (CI): 1.08, 1.09), 28% higher for those living in high-risk neighborhoods (adjusted OR = 1.28, 95% CI: 1.27, 1.30), and 69% higher for those living in very-high-risk neighborhoods (adjusted OR = 1.69, 95% CI: 1.68, 1.70) as compared with adolescents living in low-risk areas. Effect modification was observed by both individual- and neighborhood-level sociodemographic factors. These findings offer support for the hypothesis that neighborhood risks may culminate in a range of biologically mediated negative health outcomes detectable in adolescents. PMID:23035140

Characterization of cellulose production by a Gluconacetobacter xylinus strain from Kombucha.

PubMed

Nguyen, Vu Tuan; Flanagan, Bernadine; Gidley, Michael J; Dykes, Gary A

2008-11-01

The aims of this work were to characterize and improve cellulose production by a Gluconoacetobacter xylinus strain isolated from Kombucha and determine the purity and some structural features of the cellulose from this strain. Cellulose yield in tea medium with both black tea and green tea and in Hestrin and Schramm (HS) medium under both static and agitated cultures was compared. In the tea medium, the highest cellulose yield was obtained with green tea (approximately 0.20 g/L) rather than black tea (approximately 0.14 g/L). Yield in HS was higher (approximately 0.28 g/L) but did not differ between static and agitated incubation. (1)H-NMR and (13)C-NMR spectroscopy indicated that the cellulose is pure (free of acetan) and has high crystallinity, respectively. Cellulose yield was improved by changing the type and level of carbon and nitrogen source in the HS medium. A high yield of approximately 2.64 g/L was obtained with mannitol at 20 g/L and corn steep liquor at 40 g/L in combination. In the tea medium, tea at a level of 3 g/L gave the highest cellulose yield and the addition of 3 g/L of tea to the HS medium increased cellulose yield to 3.34 g/L. In conclusion, the G. xylinus strain from Kombucha had different cellulose-producing characteristics than previous strains isolated from fruit. Cellulose was produced in a pure form and showed high potential applicability. Our studies extensively characterized cellulose production from a G. xylinus strain from Kombucha for the first time, indicating both similarities and differences to strains from different sources.

[The scale and application of the norm of occupational stress on the professionals in Chengdu and Chongqing area].

PubMed

Zeng, Fan-Hua; Wang, Zhi-Ming; Wang, Mian-Zhen; Lan, Ya-Jia

2004-12-01

To establish the scale of the norm of occupational stress on the professionals and put it into practice. T scores were linear transformations of raw scores, derived to have a mean of 50 and a standard deviation of 10. The scale standard of the norm was formulated in line with the principle of normal distribution. (1) For the occupational role questionnaire (ORQ) and personal strain questionnaire (PSQ) scales, high scores suggested significant levels of occupational stress and psychological strain, respectively. T scores >/= 70 indicated a strong probability of maladaptive stress, debilitating strain, or both. T scores in 60 approximately 69 suggested mild levels of maladaptive stress and strain, and in 40 approximately 59 were within one standard deviation of the mean and should be interpreted as being within normal range. T scores < 40 indicated a relative absence of occupational stress or psychological strain. For the personal resources questionnaire (PRQ) scales, high scores indicated highly developed coping resources. T scores < 30 indicated a significant lack of coping resources. T scores in 30 approximately 39 suggested mild deficits in coping skills, and in 40 approximately 59 indicated average coping resources, where as higher scores (i.e., >/= 60) indicated increasingly strong coping resources. (2) This study provided raw score to T-score conversion tables for each OSI-R scale for the total normative sample as well as for gender, and several occupational groups, including professional engineer, professional health care, economic business, financial business, law, education and news. OSI-R profile forms for total normative samples, gender and occupation were also offered according to the conversion tables. The norm of occupational stress can be used as screening tool, organizational/occupational assessment, guide to occupational choice and intervention measures.

In vitro and in vivo response after exposure to man-made mineral and asbestos insulation fibers.

PubMed

Pickrell, J A; Hill, J O; Carpenter, R L; Hahn, F F; Rebar, A H

1983-08-01

The relative in vitro and in vivo toxicity of several types of manufactured fibrous glass insulation and crocidolite asbestos was investigated to aid in selection of a suitable glass fiber for subsequent use in inhalation exposures. The in vitro cytotoxicity to pulmonary alveolar macrophages of small glass fibers from microfiber insulation (count median diameter (CMD) approximately 0.1-0.2 micrometer) was greater than that of the larger fibers from household insulation (CMD approximately 2.4 micrometers). To screen for in vivo pulmonary toxicity, 2-21 mg of glass or asbestos fibers were administered in divided doses to male Syrian hamsters by intratracheal instillation. Animals were sacrificed at 1, 3.5 and 11 months following initial administration of material. One type of glass microfiber [count median diameter (CMD) approximately 0.1 micrometer] caused deaths from pulmonary edema at early times after instillation. High levels of asbestos, a second glass microfiber (CMD approximately 0.2 micrometer) and one type of household insulation fiber (CMD 2.3 micrometers) all resulted in increase in total collagen and mild pulmonary fibrosis at later times after instillation, although microfiber insulation produced a greater response than household insulation. Asbestos insulation produced the greatest response. A five-day inhalation exposure to a high level of glass microfibers deposited in lung less than 10 percent of the lowest instilled amount which elicited indications of lung injury. This amount did not produce significant biological changes at 1 to 12 months after exposure.

Reionization and the cosmic microwave background in an open universe

NASA Technical Reports Server (NTRS)

Persi, Fred M.

1995-01-01

If the universe was reionized at high reshift (z greater than or approximately equal to 30) or never recombined, then photon-electron scattering can erase fluctuations in the cosmic microwave background at scales less than or approximately equal to 1 deg. Peculiar motion at the surface of last scattering will then have given rise to new anisotropy at the 1 min level through the Vishniac effect. Here the observed fluctuations in galaxy counts are extrapolated to high redshifts using linear theory, and the expected anisotropy is computed. The predicted level of anisotropies is a function of Omega(sub 0) and the ratio of the density in ionized baryons to the critical density and is shown to depend strongly on the large- and small-scale power. It is not possible to make general statements about the viability of all reionized models based on current observations, but it is possible to rule out specific models for structure formation, particularly those with high baryonic content or small-scale power. The induced fluctuations are shown to scale with cosmological parameters and optical depth.

Semicomprehensive analysis of the postnatal age-related changes in the mRNA expression of sex steroidogenic enzymes and sex steroid receptors in the male rat hippocampus.

PubMed

Kimoto, Tetsuya; Ishii, Hirotaka; Higo, Shimpei; Hojo, Yasushi; Kawato, Suguru

2010-12-01

Although sex steroids play a crucial role in the postnatal brain development, the age-related changes in the hippocampal steroidogenesis remain largely unknown. We performed comprehensive investigations for the mRNA expressions of 26 sex steroidogenic enzymes/proteins and three sex steroid receptors in the male rat hippocampus, at the ages of postnatal day (PD) 1, PD4, PD7, PD10, PD14, 4 wk, and 12 wk (adult), by RT-PCR/Southern blotting analysis. The relative expression levels of these enzymes/receptors at PD1 were Srd5a1 > Star > Ar ∼ Hsd17b4 ∼ Hsd17b1 ∼ Hsd17b7 ∼ Esr1 ∼ Srd5a2 > Hsd17b3 > Esr2 > Cyp11a1 > Cyp17a1 > Cyp19a1 ∼ Hsd17b2 > 3β-hydroxysteroid dehydrogenase I. The mRNA levels of essential enzymes for progesterone/testosterone/estradiol metabolisms (Cyp17a1, Hsd17b7, and Cyp19a1) were approximately constant between PD1 and PD14 and then declined toward the adult levels. Cyp11a1 increased during PD4-PD14 and then considerably decreased toward the adult level (∼8% of PD1). Hsd17b1, Hsd17b2, and 3β-hydroxysteroid dehydrogenase I mRNA decreased approximately monotonously. Hsd17b3 increased to approximately 200% of PD1 during PD4-PD14 and was maintained at this high level. The 5α-reductase mRNA was maintained constant (Srd5a1) or decreased monotonically (Srd5a2) toward the adult level. The Esr1 level peaked at PD4 and decreased toward the adult level, whereas Ar greatly increased during PD1-PD14 and was maintained at this high level. The Star and Hsd17b4 levels were maintained constant from neonate to adult. These results suggest that the hippocampal sex steroidogenic properties are substantially altered during the postnatal development processes, which might contribute to brain sexual maturation.

Influence of Culture Media on the Radiation Resistance of Micrococcus radiodurans

PubMed Central

Krabbenhoft, K. L.; Anderson, A. W.; Elliker, P. R.

1967-01-01

The addition of NZ-case (a tryptic digest of casein) to a growth medium (PC) consisting of tryptone, glucose, and yeast extract caused a significant decrease in γ radiation resistance of Micrococcus radiodurans. The level of radiation resistance was inversely related to the concentration of NZ-case. The ld50 for this organism was approximately 700 krad when grown in tryptone, glucose, yeast extract, and dl-methionine (TGYM) broth, but it was approximately one-half as resistant when grown in a PC medium containing 0.5% NZ-case (PCNZ). The resistance to ultraviolet light was also reduced. Cultures transferred from PCNZ to TGYM media regained the high level of resistance. Images Fig. 2 Fig. 3 PMID:5340165

Assessment of aquifer properties, evapotranspiration, and the effects of ditching in the Stoney Brook watershed, Fond du Lac Reservation, Minnesota, 2006-9

USGS Publications Warehouse

Jones, Perry M.; Tomasek, Abigail A.

2015-01-01

Daily fluctuations in water levels in two wells indicated that the evapotranspiration extinction depth in the Stoney Brook watershed is approximately 4.6 to 6 feet below the land surface. A polynomial regression fit of the daily evapotranspiration rates during 2006–9 for well 1 produced a total evapotranspiration estimate of 16.1 inches from June 26 to October 6 for every year. Evapotranspiration estimated from daily water-level fluctuations in wells near ditches is relatively high. The ditch-water surface allowed for relatively high evaporation compared to the land surface, which, with a good hydraulic connection to surrounding groundwater, resulted in relatively high fluctuations in daily groundwater levels near ditches, resulting in high evapotranspiration estimates.

Label-free and highly sensitive optical imaging of detailed microcirculation within meninges and cortex in mice with the cranium left intact.

PubMed

Jia, Yali; An, Lin; Wang, Ruikang K

2010-01-01

We demonstrate for the first time that the detailed blood flow distribution within intracranial dura mater and cortex can be visualized by an ultrahigh sensitive optical microangiography (UHS-OMAG). The study uses an UHS-OMAG system operating at 1310 nm with an imaging speed at 150 frames per second that requires approximately 10 s to complete one 3-D scan of approximately 2.5 x 2.5 mm(2). The system is sensitive to blood flow with a velocity ranging from approximately 4 microms to approximately 23 mms. We show superior performance of UHS-OMAG in providing functional images of capillary level microcirculation within meninges in mice with the cranium left intact, the results of which correlate well with the standard dural histopathology.

Serial transmission in rodents of neurodegeneration from transgenic mice expressing mutant prion protein.

PubMed Central

Hsiao, K K; Groth, D; Scott, M; Yang, S L; Serban, H; Rapp, D; Foster, D; Torchia, M; Dearmond, S J; Prusiner, S B

1994-01-01

Two lines of transgenic (Tg) mice expressing high (H) levels of the mutant P101L prion protein (PrP) developed a neurologic illness and central nervous system pathology indistinguishable from experimental murine scrapie; these mice were designated Tg(MoPrP-P101L)H. Brain homogenates from Tg(MoPrP-P101L)H mice were inoculated intracerebrally into CD-1 Swiss mice, Syrian hamsters, and Tg196 mice, Tg mice expressing the MoPrP-P101L transgene at low levels. None of the CD-1 mice developed central nervous system dysfunction, whereas approximately 10% of hamsters and approximately 40% of the Tg196 mice manifested neurologic signs between 117 and 639 days after inoculation. Serial transmission of neurodegeneration in Tg196 mice and Syrian hamsters was initiated with brain extracts, producing incubation times of approximately 400 and approximately 75 days, respectively. Although the Tg(MoPrP-P101L)H mice appear to accumulate only low levels of infections prions in their brains, the serial transmission of disease to inoculated recipients argues that prion formation occurs de novo in the brains of these uninoculated animals. These Tg mouse studies, taken together with similar findings in humans dying of inherited prion diseases, provide additional evidence that prions lack a foreign nucleic acid. Images PMID:7916462

PERCHLORATE IN FERTILIZERS?: ANALYSIS BY RAMAN SPECTROSCOPY

EPA Science Inventory

Recently, we and others found perchlorate at high levels (approximately 500 - 8000 mg/kg) in 90+% of 25+ fertilizers (primarily lawn-and-garden products) that are not identified as containing components derived from mined Chile saltpeter, which is known to contain perchlorate as ...

Effects of Ultra-Clean and centrifugal filtration on rolling-element bearing life

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.; Moyer, D. W.; Needelman, W. M.

1981-01-01

Fatigue tests were conducted on groups of 65-millimeter bore diameter deep-groove ball bearings in a MIL-L-23699 lubricant under two levels of filtration. In one test series, the oil cleanliness was maintained at an exceptionally high level (better than a class "000" per NAS 1638) with a 3 micron absolute barrier filter. These tests were intended to determine the "upper limit" in bearing life under the strictest possible lubricant cleanliness conditions. In the tests using a centrifugal oil filter, contaminants of the type found in aircraft engine filters were injected into the filters' supply line at 125 milligrams per bearing-hour. "Ultra-clean" lubrication produced bearing fatigue lives that were approximately twice that obtained in previous tests with contaminated oil using 3 micron absolute filtration and approximately three times that obtained with 49 micron filtration. It was also observed that the centrifugal oil filter had approximately the same effectiveness as a 30 micron absolute filter in preventing bearing surface damage.

MRO's High Resolution Imaging Science Experiment (HiRISE): Polar Science Expectations

NASA Technical Reports Server (NTRS)

McEwen, A.; Herkenhoff, K.; Hansen, C.; Bridges, N.; Delamere, W. A.; Eliason, E.; Grant, J.; Gulick, V.; Keszthelyi, L.; Kirk, R.

2003-01-01

The Mars Reconnaissance Orbiter (MRO) is expected to launch in August 2005, arrive at Mars in March 2006, and begin the primary science phase in November 2006. MRO will carry a suite of remote-sensing instruments and is designed to routinely point off-nadir to precisely target locations on Mars for high-resolution observations. The mission will have a much higher data return than any previous planetary mission, with 34 Tbits of returned data expected in the first Mars year in the mapping orbit (255 x 320 km). The HiRISE camera features a 0.5 m telescope, 12 m focal length, and 14 CCDs. We expect to acquire approximately 10,000 observations in the primary science phase (approximately 1 Mars year), including approximately 2,000 images for 1,000 stereo targets. Each observation will be accompanied by a approximately 6 m/pixel image over a 30 x 45 km region acquired by MRO s context imager. Many HiRISE images will be full resolution in the center portion of the swath width and binned (typically 4x4) on the sides. This provides two levels of context, so we step out from 0.3 m/pixel to 1.2 m/pixel to 6 m/pixel (at 300 km altitude). We expect to cover approximately 1% of Mars at better than 1.2 m/pixel, approximately 0.1% at 0.3 m/pixel, approximately 0.1% in 3 colors, and approximately 0.05% in stereo. Our major challenge is to find the dey contacts, exposures and type morphologies to observe.

California Conference on High Blood Pressure Control in the Spanish-Speaking Community (Los Angeles, California, April 1-2, 1978). Summary Report.

ERIC Educational Resources Information Center

National Institutes of Health (DHEW), Bethesda, MD. High Blood Pressure Information Center.

As part of the National High Blood Pressure Education Program effort, the conference explored the implications and impact of the prevalence of hypertension in Spanish-speaking populations in California. Approximately 150 experts in health fields, representing all levels of government, public and private health care providers, consumers, and health…

Resistant Starch: Variation among High Amylose Rice Varieties and Its Relationship with Apparent Amylose Content, Pasting Properties and Cooking Methods

USDA-ARS?s Scientific Manuscript database

Resistant starch (RS), which is not hydrolyzed in the small intestines, has proposed health benefits. We evaluated a set of 40 high amylose rice varieties for RS levels in cooked rice and approximately a 1.9-fold difference was found. The highest ones had more than two-fold greater RS concentration ...

Improving Student Success Using Predictive Models and Data Visualisations

ERIC Educational Resources Information Center

Essa, Alfred; Ayad, Hanan

2012-01-01

The need to educate a competitive workforce is a global problem. In the US, for example, despite billions of dollars spent to improve the educational system, approximately 35% of students never finish high school. The drop rate among some demographic groups is as high as 50-60%. At the college level in the US only 30% of students graduate from…

Statistical comparison of a hybrid approach with approximate and exact inference models for Fusion 2+

NASA Astrophysics Data System (ADS)

Lee, K. David; Wiesenfeld, Eric; Gelfand, Andrew

2007-04-01

One of the greatest challenges in modern combat is maintaining a high level of timely Situational Awareness (SA). In many situations, computational complexity and accuracy considerations make the development and deployment of real-time, high-level inference tools very difficult. An innovative hybrid framework that combines Bayesian inference, in the form of Bayesian Networks, and Possibility Theory, in the form of Fuzzy Logic systems, has recently been introduced to provide a rigorous framework for high-level inference. In previous research, the theoretical basis and benefits of the hybrid approach have been developed. However, lacking is a concrete experimental comparison of the hybrid framework with traditional fusion methods, to demonstrate and quantify this benefit. The goal of this research, therefore, is to provide a statistical analysis on the comparison of the accuracy and performance of hybrid network theory, with pure Bayesian and Fuzzy systems and an inexact Bayesian system approximated using Particle Filtering. To accomplish this task, domain specific models will be developed under these different theoretical approaches and then evaluated, via Monte Carlo Simulation, in comparison to situational ground truth to measure accuracy and fidelity. Following this, a rigorous statistical analysis of the performance results will be performed, to quantify the benefit of hybrid inference to other fusion tools.

Solidification of Savannah River plant high level waste

NASA Astrophysics Data System (ADS)

Maher, R.; Shafranek, L. F.; Kelley, J. A.; Zeyfang, R. W.

1981-11-01

Authorization for construction of the Defense Waste Processing Facility (DWPF) is expected in FY-83. The optimum time for stage 2 authorization is about three years later. Detailed design and construction will require approximately five years for stage 1, with stage 2 construction completed about two to three years later. Production of canisters of waste glass would begin in 1988, and the existing backlog of high level waste sludge stored at SRP would be worked off by about the year 2000. Stage 2 operation could begin in 1990. The technology and engineering are ready for construction and eventual operation of the DWPF for immobilizing high level radioactive waste at Savannah River Plant (SRP). Proceeding with this project will provide the public, and the leadership of this country, with a crucial demonstration that a major quanitity of existing high level nuclear wastes can be safely and permanently immobilized.

Effects of birthplace and individual genetic admixture on lung volume and exercise phenotypes of Peruvian Quechua.

PubMed

Brutsaert, Tom D; Parra, Esteban; Shriver, Mark; Gamboa, Alfredo; Palacios, Jose-Antonio; Rivera, Maria; Rodriguez, Ivette; León-Velarde, Fabiola

2004-04-01

Forced vital capacity (FVC) and maximal exercise response were measured in two populations of Peruvian males (age, 18-35 years) at 4,338 m who differed by the environment in which they were born and raised, i.e., high altitude (Cerro de Pasco, Peru, BHA, n = 39) and sea level (Lima, Peru, BSL, n = 32). BSL subjects were transported from sea level to 4,338 m, and were evaluated within 24 hr of exposure to hypobaric hypoxia. Individual admixture level (ADMIX, % Spanish ancestry) was estimated for each subject, using 22 ancestry-informative genetic markers and also by skin reflectance measurement (MEL). Birthplace accounted for the approximately 10% larger FVC (P < 0.001), approximately 15% higher maximal oxygen consumption (VO(2)max, ml.min(-1).kg(-1)) (P < 0.001), and approximately 5% higher arterial oxygen saturation during exercise (SpO(2)) (P < 0.001) of BHA subjects. ADMIX was low in both study groups, averaging 9.5 +/- 2.6% and 2.1 +/- 0.3% in BSL and BHA subjects, respectively. Mean underarm MEL was significantly higher in the BSL group (P < 0.001), despite higher ADMIX. ADMIX was not associated with any study phenotype, but study power was not sufficient to evaluate hypotheses of genetic adaptation via the ADMIX variable. MEL and FVC were positively correlated in the BHA (P = 0.035) but not BSL (P = 0.335) subjects. However, MEL and ADMIX were not correlated across the entire study sample (P = 0.282). In summary, results from this study emphasize the importance of developmental adaptation to high altitude. While the MEL-FVC correlation may reflect genetic adaptation to high altitude, study results suggest that alternate (environmental) explanations be considered. Copyright 2003 Wiley-Liss, Inc.

Tree-level correlations in the strong field regime

NASA Astrophysics Data System (ADS)

Gelis, François

2017-09-01

We consider the correlation function of an arbitrary number of local observables in quantum field theory, in situations where the field amplitude is large. Using a quasi-classical approximation (valid for a highly occupied initial mixed state, or for a coherent initial state if the classical dynamics has instabilities), we show that at tree level these correlations are dominated by fluctuations at the initial time. We obtain a general expression of the correlation functions in terms of the classical solution of the field equation of motion and its derivatives with respect to its initial conditions, that can be arranged graphically as the sum of labeled trees where the nodes are the individual observables, and the links are pairs of derivatives acting on them. For 3-point (and higher) correlation functions, there are additional tree-level terms beyond the quasi-classical approximation, generated by fluctuations in the bulk.

A Comparison of Actual and Perceived Sexual Risk among Older Adults

PubMed Central

Syme, Maggie L.; Cohn, Tracy J.; Barnack-Tavlaris, Jessica

2017-01-01

Sexual risk among older adults (OAs) is prevalent, though little is known about the accuracy of sexual risk perceptions. Thus, the aim was to determine the accuracy of sexual risk perceptions among OAs by examining concordance between self-reported sexual risk behaviors and perceived risk. Data on OAs aged 50 to 92 were collected via Amazon Mechanical Turk. Frequency of sexual risk behaviors (past 6 months) were reported along with perceived risk (i.e., STI susceptibility). Accuracy categories (accurate, underestimated, overestimated) were established based on dis/concordance between risk levels (low, moderate, high) and perceived risk (not susceptible, somewhat susceptible, very susceptible). Approximately half of the sample reported engaging in vaginal (49%) and/or oral sex (43%) without a condom in the past 6 months. However, approximately two-thirds of the sample indicated they were “not susceptible” to STIs. No relationship was found between risk behaviors and risk perceptions, and approximately half (48.1%) of OAs in the sample underestimated their risk. Accuracy was found to decrease as sexual risk level increased, with 93.1% of high risk OAs underestimating their risk. Several sexual risk behaviors are prevalent among OAs, particularly men. However, perception of risk is often inaccurate and warrants attention. PMID:26813853

A Comparison of Actual and Perceived Sexual Risk Among Older Adults.

PubMed

Syme, Maggie L; Cohn, Tracy J; Barnack-Tavlaris, Jessica

2017-02-01

Sexual risk among older adults (OAs) is prevalent, though little is known about the accuracy of sexual risk perceptions. Thus, the aim was to determine the accuracy of sexual risk perceptions among OAs by examining concordance between self-reported sexual risk behaviors and perceived risk. Data on OAs aged 50 to 92 were collected via Amazon.com's Mechanical Turk. Frequency of sexual risk behaviors (past six months) were reported along with perceived risk, namely, sexually transmitted infection (STI) susceptibility. Accuracy categories (accurate, underestimated, overestimated) were established based on dis/concordance between risk levels (low, moderate, high) and perceived risk (not susceptible, somewhat susceptible, very susceptible). Approximately half of the sample reported engaging in vaginal (49%) and/or oral sex (43%) without a condom in the past six months. However, approximately two-thirds of the sample indicated they were "not susceptible" to STIs. No relationship was found between risk behaviors and risk perceptions, and approximately half (48.1%) of OAs in the sample underestimated their risk. Accuracy was found to decrease as sexual risk level increased, with 93.1% of high-risk OAs underestimating their risk. Several sexual risk behaviors are prevalent among OAs, particularly men. However, perception of risk is often inaccurate and warrants attention.

High-throughput PBPK and Microdosimetry: Cell-level Exposures in a Virtual Tissue Context (WC9)

EPA Science Inventory

Toxicokinetic (TK) models can determine whether chemical exposures produce potentially hazardous tissue concentrations. Tissue microdosimetry TK models relate whole-body chemical exposures to cell-scale concentrations. As a proof of concept, we approximated the micro-anatomic arc...

Connections, Engagement, and Presence

ERIC Educational Resources Information Center

Hoskins, Barbara J.

2012-01-01

A well-designed online course can provide opportunities for active learning, creative thinking, and knowledge construction with high levels of student satisfaction. The latest Babson/Sloan survey on online education, however, shows that approximately one-third of the chief academic officer participants still consider online education inferior to…

Benchmark studies on the building blocks of DNA. 3. Watson-Crick and stacked base pairs.

PubMed

Szalay, Péter G; Watson, Thomas; Perera, Ajith; Lotrich, Victor; Bartlett, Rodney J

2013-04-18

Excited states of stacked adenine-thymine and guanine-cytosine pairs as well as the Watson-Crick pair of guanine-thymine have been investigated using the equation of motion coupled-cluster (EOM-CC) method with single and double as well as approximate triple excitations. Transitions have been assigned, and the form of the excitations has been analyzed. The majority of the excitations could be classified as localized on the nucleobases, but for all three studied systems, charge-transfer (CT) transitions could also be identified. The main aim of this study was to compare the performance of lower-level methods (ADC(2) and TDDFT) to the high-level EOM-CC ones. It was shown that both ADC(2) and TDDFT with long-range correction have nonsystematic error in excitation energies, causing alternation of the energetic ordering of the excitations. Considering the high costs of the EOM-CC calculations, there is a need for reliable new approximate methods.

Homodimeric β-Galactosidase from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081: Expression in Lactobacillus plantarum and Biochemical Characterization

PubMed Central

2012-01-01

The lacZ gene from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081, encoding a β-galactosidase of the glycoside hydrolase family GH2, was cloned into different inducible lactobacillal expression vectors for overexpression in the host strain Lactobacillus plantarum WCFS1. High expression levels were obtained in laboratory cultivations with yields of approximately 53000 U of β-galactosidase activity per liter of medium, which corresponds to ∼170 mg of recombinant protein per liter and β-galactosidase levels amounting to 63% of the total intracellular protein of the host organism. The wild-type (nontagged) and histidine-tagged recombinant enzymes were purified to electrophoretic homogeneity and further characterized. β-Galactosidase from L. bulgaricus was used for lactose conversion and showed very high transgalactosylation activity. The maximum yield of galacto-oligosaccharides (GalOS) was approximately 50% when using an initial concentration of 600 mM lactose, indicating that the enzyme can be of interest for the production of GalOS. PMID:22283494

Homodimeric β-galactosidase from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081: expression in Lactobacillus plantarum and biochemical characterization.

PubMed

Nguyen, Tien-Thanh; Nguyen, Hoang Anh; Arreola, Sheryl Lozel; Mlynek, Georg; Djinović-Carugo, Kristina; Mathiesen, Geir; Nguyen, Thu-Ha; Haltrich, Dietmar

2012-02-22

The lacZ gene from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081, encoding a β-galactosidase of the glycoside hydrolase family GH2, was cloned into different inducible lactobacillal expression vectors for overexpression in the host strain Lactobacillus plantarum WCFS1. High expression levels were obtained in laboratory cultivations with yields of approximately 53000 U of β-galactosidase activity per liter of medium, which corresponds to ~170 mg of recombinant protein per liter and β-galactosidase levels amounting to 63% of the total intracellular protein of the host organism. The wild-type (nontagged) and histidine-tagged recombinant enzymes were purified to electrophoretic homogeneity and further characterized. β-Galactosidase from L. bulgaricus was used for lactose conversion and showed very high transgalactosylation activity. The maximum yield of galacto-oligosaccharides (GalOS) was approximately 50% when using an initial concentration of 600 mM lactose, indicating that the enzyme can be of interest for the production of GalOS.

Piezoelectric Flexible LCP-PZT Composites for Sensor Applications at Elevated Temperatures

NASA Astrophysics Data System (ADS)

Tolvanen, Jarkko; Hannu, Jari; Juuti, Jari; Jantunen, Heli

2018-03-01

In this paper fabrication of piezoelectric ceramic-polymer composites is demonstrated via filament extrusion enabling cost-efficient large-scale production of highly bendable pressure sensors feasible for elevated temperatures. These composites are fabricated by utilizing environmentally resistant and stable liquid crystal polymer matrix with addition of lead zirconate titanate at loading levels of 30 vol%. These composites, of approximately 0.99 mm thick and length of > 50 cm, achieved excellent bendability with minimum bending radius of 6.6 cm. The maximum piezoelectric coefficients d33 and g33 of the composites were > 14 pC/N and > 108 mVm/N at pressure < 10 kPa. In all cases, the piezoelectric charge coefficient (d33) of the composites decreased as a function of pressure. Also, piezoelectric coefficient (d33) further decreased in the case of increased frequency press-release cycle sand pre-stress levels by approximately 37-50%. However, the obtained results provide tools for fabricating novel piezoelectric sensors in highly efficient way for environments with elevated temperatures.

NO2/NO partitioning as a test of stratospheric ClO concentrations over Antarctica

NASA Technical Reports Server (NTRS)

Webster, Christopher R.

1987-01-01

Physical conditions in the 10-20 km region of the Antarctic stratosphere make the (NO2)/(NO) ratio particularly sensitive to high chlorine levels in the form of ClO. According to simple known photochemical relationships between NO2, NO, ClO, and O3, high ClO levels of 1 ppbv over Antarctica must be accompanied by large values of the (NO2)/(NO) ratio. At high ClO abundances, the (NO2)/(NO) ratio is approximately proportional to the ClO concentration. It is proposed that in-situ measurements of the (NO2)/(NO) ratio could be used to test the high chlorine hypothesis.

Level-Set Variational Implicit-Solvent Modeling of Biomolecules with the Coulomb-Field Approximation

PubMed Central

2011-01-01

Central in the variational implicit-solvent model (VISM) [Dzubiella, Swanson, and McCammon Phys. Rev. Lett.2006, 96, 087802 and J. Chem. Phys.2006, 124, 084905] of molecular solvation is a mean-field free-energy functional of all possible solute–solvent interfaces or dielectric boundaries. Such a functional can be minimized numerically by a level-set method to determine stable equilibrium conformations and solvation free energies. Applications to nonpolar systems have shown that the level-set VISM is efficient and leads to qualitatively and often quantitatively correct results. In particular, it is capable of capturing capillary evaporation in hydrophobic confinement and corresponding multiple equilibrium states as found in molecular dynamics (MD) simulations. In this work, we introduce into the VISM the Coulomb-field approximation of the electrostatic free energy. Such an approximation is a volume integral over an arbitrary shaped solvent region, requiring no solutions to any partial differential equations. With this approximation, we obtain the effective boundary force and use it as the “normal velocity” in the level-set relaxation. We test the new approach by calculating solvation free energies and potentials of mean force for small and large molecules, including the two-domain protein BphC. Our results reveal the importance of coupling polar and nonpolar interactions in the underlying molecular systems. In particular, dehydration near the domain interface of BphC subunits is found to be highly sensitive to local electrostatic potentials as seen in previous MD simulations. This is a first step toward capturing the complex protein dehydration process by an implicit-solvent approach. PMID:22346739

Slow-roll corrections in multi-field inflation: a separate universes approach

NASA Astrophysics Data System (ADS)

Karčiauskas, Mindaugas; Kohri, Kazunori; Mori, Taro; White, Jonathan

2018-05-01

In view of cosmological parameters being measured to ever higher precision, theoretical predictions must also be computed to an equally high level of precision. In this work we investigate the impact on such predictions of relaxing some of the simplifying assumptions often used in these computations. In particular, we investigate the importance of slow-roll corrections in the computation of multi-field inflation observables, such as the amplitude of the scalar spectrum Pζ, its spectral tilt ns, the tensor-to-scalar ratio r and the non-Gaussianity parameter fNL. To this end we use the separate universes approach and δ N formalism, which allows us to consider slow-roll corrections to the non-Gaussianity of the primordial curvature perturbation as well as corrections to its two-point statistics. In the context of the δ N expansion, we divide slow-roll corrections into two categories: those associated with calculating the correlation functions of the field perturbations on the initial flat hypersurface and those associated with determining the derivatives of the e-folding number with respect to the field values on the initial flat hypersurface. Using the results of Nakamura & Stewart '96, corrections of the first kind can be written in a compact form. Corrections of the second kind arise from using different levels of slow-roll approximation in solving for the super-horizon evolution, which in turn corresponds to using different levels of slow-roll approximation in the background equations of motion. We consider four different levels of approximation and apply the results to a few example models. The various approximations are also compared to exact numerical solutions.

Background Selection in Partially Selfing Populations

PubMed Central

Roze, Denis

2016-01-01

Self-fertilizing species often present lower levels of neutral polymorphism than their outcrossing relatives. Indeed, selfing automatically increases the rate of coalescence per generation, but also enhances the effects of background selection and genetic hitchhiking by reducing the efficiency of recombination. Approximations for the effect of background selection in partially selfing populations have been derived previously, assuming tight linkage between deleterious alleles and neutral loci. However, loosely linked deleterious mutations may have important effects on neutral diversity in highly selfing populations. In this article, I use a general method based on multilocus population genetics theory to express the effect of a deleterious allele on diversity at a linked neutral locus in terms of moments of genetic associations between loci. Expressions for these genetic moments at equilibrium are then computed for arbitrary rates of selfing and recombination. An extrapolation of the results to the case where deleterious alleles segregate at multiple loci is checked using individual-based simulations. At high selfing rates, the tight linkage approximation underestimates the effect of background selection in genomes with moderate to high map length; however, another simple approximation can be obtained for this situation and provides accurate predictions as long as the deleterious mutation rate is not too high. PMID:27075726

Geo-Spatial Characterization of Soil Mercury and Arsenic at a High-Altitude Bolivian Gold Mine.

PubMed

Johnson, Glen D; Pavilonis, Brian; Caravanos, Jack; Grassman, Jean

2018-02-01

Soil mercury concentrations at a typical small-scale mine site in the Bolivian Andes were elevated (28-737 mg/kg or ppm) in localized areas where mercury amalgams were either formed or vaporized to release gold, but was not detectable beyond approximately 10 m from its sources. Arsenic was measurable, exceeding known background levels throughout the mine site (77-137,022 ppm), and was also measurable through the local village of Ingenio (36-1803 ppm). Although arsenic levels were high at all surveyed locations, its spatial pattern followed mercury, being highest where mercury was high.

(Fe II) emission from high-density regions in the Orion Nebula

NASA Technical Reports Server (NTRS)

Bautista, Manuel A.; Pradhan, Anil K.; Osterbrock, Donald E.

1994-01-01

Direct spectroscopic evidence of high-density regions in the Orion Nebula, N(sub e) approximately equals 10(exp 5)-10(exp 7)/cu cm, is obtained from the forbidden optical and near-IR (Fe II) emission lines, using new atomic data. Calculations for level populations and line ratios are carried out using 16, 35, and 142 level collisional-radiative models for Fe II. Estimates of Fe(+) abundances derived from the near-infrared and the optical line intensities are consistent with a high density of 10(exp 6)/cu cm in the (Fe II) emitting regions. Important consequences for abundance determinations in the nebula are pointed out.

Wireless amperometric neurochemical monitoring using an integrated telemetry circuit.

PubMed

Roham, Masoud; Halpern, Jeffrey M; Martin, Heidi B; Chiel, Hillel J; Mohseni, Pedram

2008-11-01

An integrated circuit for wireless real-time monitoring of neurochemical activity in the nervous system is described. The chip is capable of conducting high-resolution amperometric measurements in four settings of the input current. The chip architecture includes a first-order Delta Sigma modulator (Delta Sigma M) and a frequency-shift-keyed (FSK) voltage-controlled oscillator (VCO) operating near 433 MHz. It is fabricated using the AMI 0.5 microm double-poly triple-metal n-well CMOS process, and requires only one off-chip component for operation. Measured dc current resolutions of approximately 250 fA, approximately 1.5 pA, approximately 4.5 pA, and approximately 17 pA were achieved for input currents in the range of +/-5, +/-37, +/-150, and +/-600 nA, respectively. The chip has been interfaced with a diamond-coated, quartz-insulated, microneedle, tungsten electrode, and successfully recorded dopamine concentration levels as low as 0.5 microM wirelessly over a transmission distance of approximately 0.5 m in flow injection analysis experiments.

Infrared photometry of the black hole candidate Sagittarius A*

NASA Technical Reports Server (NTRS)

Close, Laird M.; Mccarthy, Donald W. JR.; Melia, Fulvio

1995-01-01

An infrared source has been imaged within 0.2 +/- 0.3 arcseconds of the unique Galactic center radio source Sgr A* High angular resolution (averaged value of the Full Width at Half Maximum (FWHM) approximately 0.55 arcseconds) was achieved by rapid (approximately 50 Hz) real-time images motion compensation. The source's near-infrared magnitudes (K = 12.1 +/- 0.3, H = 13.7 +/- 0.3, and J = 16.6 +/- 0.4) are consistent with a hot object reddened by the local extinction A(sub v) approximately 27). At the 3 sigma level of confidence, a time series of 80 images limits the source variability to less than 50% on timescales from 3 to 30 minutes. The photometry is consistent with the emission from a simple accretion disk model for a approximately 1 x 10(exp 6) solar mass black hole. However, the fluxes are also consistent with a hot luminous (L approximately 10(exp 3.5) to 10(exp 4-6) solar luminosity) central cluster star positionally coincident with Sgr A*.

Adequacy of selected evapotranspiration approximations for hydrologic simulation

USGS Publications Warehouse

Sumner, D.M.

2006-01-01

Evapotranspiration (ET) approximations, usually based on computed potential ET (PET) and diverse PET-to-ET conceptualizations, are routinely used in hydrologic analyses. This study presents an approach to incorporate measured (actual) ET data, increasingly available using micrometeorological methods, to define the adequacy of ET approximations for hydrologic simulation. The approach is demonstrated at a site where eddy correlation-measured ET values were available. A baseline hydrologic model incorporating measured ET values was used to evaluate the sensitivity of simulated water levels, subsurface recharge, and surface runoff to error in four ET approximations. An annually invariant pattern of mean monthly vegetation coefficients was shown to be most effective, despite the substantial year-to-year variation in measured vegetation coefficients. The temporal variability of available water (precipitation minus ET) at the humid, subtropical site was largely controlled by the relatively high temporal variability of precipitation, benefiting the effectiveness of coarse ET approximations, a result that is likely to prevail at other humid sites.

Cloning, heterologous expression, and in situ characterization of the first high affinity nucleobase transporter from a protozoan.

PubMed

Burchmore, Richard J S; Wallace, Lynsey J M; Candlish, Denise; Al-Salabi, Mohammed I; Beal, Paul R; Barrett, Michael P; Baldwin, Stephen A; de Koning, Harry P

2003-06-27

While multiple nucleoside transporters, some of which can also transport nucleobases, have been cloned in recent years from many different organisms, no sequence information is available for the high affinity, nucleobase-selective transporters of metazoa, parazoa, or protozoa. We have identified a gene, TbNBT1, from Trypanosoma brucei brucei that encodes a 435-residue protein of the equilibrative nucleoside transporter superfamily. The gene was expressed in both the procyclic and bloodstream forms of the organism. Expression of TbNBT1 in a Saccharomyces cerevisiae strain lacking an endogenous purine transporter allowed growth on adenine as sole purine source and introduced a high affinity transport activity for adenine and hypoxanthine, with Km values of 2.1 +/- 0.6 and 0.66 +/- 0.22 microm, respectively, as well as high affinity for xanthine, guanine, guanosine, and allopurinol and moderate affinity for inosine. A transporter with an indistinguishable kinetic profile was identified in T. b. brucei procyclics and designated H4. RNA interference of TbNBT1 in procyclics reduced cognate mRNA levels by approximately 80% and H4 transport activity by approximately 90%. Expression of TbNBT1 in Xenopus oocytes further confirmed that this gene encodes the first high affinity nucleobase transporter from protozoa or animals to be identified at the molecular level.

Phenytoin intoxication with no symptoms correlated with serum drug level: a case study.

PubMed

Avcil, Mucahit; Duman, Ali; Turkdogan, Kenan Ahmet; Kapci, Mucahit; Akoz, Ayhan; Canakci, Selcuk Eren; Ozluer, Yunus Emre

2015-01-01

In high-dose intake of phenytoin, which is used frequently to treat epilepsy, nystagmus, diplopia, nausea-vomiting, lethargy, confusion, seizure, and coma can be observed. In recent studies on phenytoin intoxication, in which seizure and coma were observed in drug levels greater than 50 ug/mL. The serum phenytoin level of a patient, who consumed approximately 100 pcs of 100 mg phenytoin tablets in an effort to commit suicide, and who had no pathological finding in her neurologic examination, was 124 ug/mL. High drug level and the absence of toxic effect (or the absence of toxic effect correlated with the drug level) indicates that cytochrome P450 is functioning, but there can be a mutation in the MDR1 gene. In our case study, we report on phenytoin intoxication in a patient having a high level of phenytoin but no symptoms correlated with serum drug level, as supported by the findings in the literature.

Implementation of a Distributed Object-Oriented Database Management System

DTIC Science & Technology

1989-03-01

and heuristic algorithms. A method for determining ueit allocation by splitting relations in the conceptual schema base on queries and updates is...level framworks can provide to the user the appearance of many tools to be closely integrated. In particular, the KBSA tools use many high level...development process should begin first with conceptual design of the system. Approximately one month should be used to decide how the new projects

Incomplete Sparse Approximate Inverses for Parallel Preconditioning

DOE PAGES

Anzt, Hartwig; Huckle, Thomas K.; Bräckle, Jürgen; ...

2017-10-28

In this study, we propose a new preconditioning method that can be seen as a generalization of block-Jacobi methods, or as a simplification of the sparse approximate inverse (SAI) preconditioners. The “Incomplete Sparse Approximate Inverses” (ISAI) is in particular efficient in the solution of sparse triangular linear systems of equations. Those arise, for example, in the context of incomplete factorization preconditioning. ISAI preconditioners can be generated via an algorithm providing fine-grained parallelism, which makes them attractive for hardware with a high concurrency level. Finally, in a study covering a large number of matrices, we identify the ISAI preconditioner as anmore » attractive alternative to exact triangular solves in the context of incomplete factorization preconditioning.« less

Changes in amount and intracellular distribution of androgen receptor in human foreskin as a function of age.

PubMed Central

Roehrborn, C G; Lange, J L; George, F W; Wilson, J D

1987-01-01

To provide insight into the factors that control growth of the penis we measured the amount and intracellular distribution of specific high affinity androgen receptor in foreskins obtained at circumcision from 49 males varying in age from newborn to 59 yr. Total (cytosolic plus nuclear extract) androgen receptor decreased from approximately 40 fmol/g tissue weight in newborn foreskins to approximately 25 fmol/g by 1 yr of age. The amount of receptor rose in childhood to approximately 180 fmol/g in the late teenage years and fell thereafter to approximately 20-40 fmol/g in men older than 40 yr. The amount of receptor in the nuclear fraction increased at the time of puberty and subsequently decreased in parallel with the decline in total receptor level. These changes in androgen-receptor amount are similar when expressed per milligram DNA or per milligram protein. Images PMID:3491838

Correction of the near threshold behavior of electron collisional excitation cross-sections in the plane-wave Born approximation

NASA Astrophysics Data System (ADS)

Kilcrease, D. P.; Brookes, S.

2013-12-01

The modeling of NLTE plasmas requires the solution of population rate equations to determine the populations of the various atomic levels relevant to a particular problem. The equations require many cross sections for excitation, de-excitation, ionization and recombination. A simple and computational fast way to calculate electron collisional excitation cross-sections for ions is by using the plane-wave Born approximation. This is essentially a high-energy approximation and the cross section suffers from the unphysical problem of going to zero near threshold. Various remedies for this problem have been employed with varying degrees of success. We present a correction procedure for the Born cross-sections that employs the Elwert-Sommerfeld factor to correct for the use of plane waves instead of Coulomb waves in an attempt to produce a cross-section similar to that from using the more time consuming Coulomb Born approximation. We compare this new approximation with other, often employed correction procedures. We also look at some further modifications to our Born Elwert procedure and its combination with Y.K. Kim's correction of the Coulomb Born approximation for singly charged ions that more accurately approximate convergent close coupling calculations.

Level dependence of distortion product otoacoustic emissions in the leopard frog, Rana pipiens pipiens.

PubMed

Meenderink, Sebastiaan W F; van Dijk, Pim

2004-06-01

The inner ear of frogs holds two papillae specialized in detecting airborne sound, the amphibian papilla (AP) and the basilar papilla (BP). We measured input-output (I/O) curves of distortion product otoacoustic emissions (DPOAEs) from both papillae, and compared their properties. As in other vertebrates, DPOAE I/O curves showed two distinct segments, separated by a notch or kneepoint. The slope of the low-level segment was conspicuously different between the AP and the BP. For DPOAE I/O curves from the AP, slopes were < or = 1 dB/dB, similar to what is found in mammals, birds and some lizards. For DPOAE I/O curves from the BP these slopes were much steeper (approximately 2 dB/dB). Slopes found at high stimulus levels were similar in the AP and the BP (approximately 2 dB/dB). This quantitative difference between the low-level slopes for DPOAEs from the AP and the BP may signify the involvement of different mechanisms in low-level DPOAE generation for the two papillae, respectively.

Binary-selectable detector holdoff circuit

NASA Technical Reports Server (NTRS)

Kadrmas, K. A.

1974-01-01

High-speed switching circuit protects detectors from sudden, extremely-intense backscattered radiation that results from short-range atmospheric dust layers, or low-level clouds, entering laser/radar field of view. Function of circuit is to provide computer-controlled switching of photodiode detector, preamplifier power-supply voltages, in approximately 10 nanoseconds.

Analytical Tools for Investigating and Modeling Agent-Based Systems

DTIC Science & Technology

2005-06-01

of Black Holes Cluster 10 : Juan M. Maldacena (1924), Journal of High Energy Physics Field theory models for tachyon and gauge field string dy...namics; Super-Poincare Invariant Superstring Field The- ory; Level Four Approximation to the Tachyon Potential in Superstring Field Theory; SO(32) Spinors

Current (2004-07) Conditions and Changes in Ground-Water Levels from Predevelopment to 2007, Southern High Plains Aquifer, Southeast New Mexico-Lea County Underground Water Basin

USGS Publications Warehouse

Tillery, Anne

2008-01-01

The Southern High Plains aquifer is the principal aquifer and primary source of water in southeastern New Mexico. The Lea County portion of the aquifer covers approximately the northern two thirds of the 4,393-square-mile county. Successful water-supply planning for New Mexico's Southern High Plains requires knowledge of the current aquifer conditions and a context from which to estimate future trends given current aquifer-management policy. Maps representing water-level declines, current (2007) water levels, aquifer saturated thickness, and depth to water accompanied by hydrographs from representative wells for the Southern High Plains aquifer in the Lea County Underground Water Basin were prepared in cooperation with the New Mexico Office of the State Engineer. Results of this mapping effort show the water level has declined as much as 97 feet in the Lea County Underground Water Basin from predevelopment (1914-54) to 2007 with rates as high as 0.88 feet per year.

Broadband Acoustic Environment at a Tidal Energy Site in Puget Sound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Jinshan; Deng, Zhiqun; Martinez, Jayson J.

2012-04-04

Admiralty Inlet has been selected as a potential tidal energy site. It is located near shipping lanes, is a highly variable acoustic environment, and is frequented by the endangered southern resident killer whale (SRKW). Resolving environmental impacts is the first step to receiving approval to deploy tidal turbines. Several monitoring technologies are being considered to determine the presence of SRKW near the turbines. Broadband noise level measurements are critical for determining design and operational specifications of these technologies. Acoustic environment data at the proposed site was acquired at different depths using a cabled vertical line array from three different cruisesmore » during high tidal period in February, May, and June 2011. The ambient noise level decreases approximately 25 dB re 1 μPa per octave from frequency ranges of 1 kHz to 70 kHz, and increases approximately 20 dB re 1 μPa per octave for the frequency from 70 kHz to 200 kHz. The difference of noise pressure levels in different months varies from 10 to 30 dB re 1 μPa for the frequency range below 70 kHz. Commercial shipping and ferry vessel traffic were found to be the most significant contributors to sound pressure levels for the frequency range from 100 Hz to 70 kHz, and the variation could be as high as 30 dB re 1 μPa. These noise level measurements provide the basic information for designing and evaluating both active and passive monitoring systems proposed for deploying and operating for tidal power generation alert system.« less

Pushing the limits of high-resolution functional MRI using a simple high-density multi-element coil design.

PubMed

Petridou, N; Italiaander, M; van de Bank, B L; Siero, J C W; Luijten, P R; Klomp, D W J

2013-01-01

Recent studies have shown that functional MRI (fMRI) can be sensitive to the laminar and columnar organization of the cortex based on differences in the spatial and temporal characteristics of the blood oxygenation level-dependent (BOLD) signal originating from the macrovasculature and the neuronal-specific microvasculature. Human fMRI studies at this scale of the cortical architecture, however, are very rare because the high spatial/temporal resolution required to explore these properties of the BOLD signal are limited by the signal-to-noise ratio. Here, we show that it is possible to detect BOLD signal changes at an isotropic spatial resolution as high as 0.55 mm at 7 T using a high-density multi-element surface coil with minimal electronics, which allows close proximity to the head. The coil comprises of very small, 1 × 2-cm(2) , elements arranged in four flexible modules of four elements each (16-channel) that can be positioned within 1 mm from the head. As a result of this proximity, tissue losses were five-fold greater than coil losses and sufficient to exclude preamplifier decoupling. When compared with a standard 16-channel head coil, the BOLD sensitivity was approximately 2.2-fold higher for a high spatial/temporal resolution (1 mm isotropic/0.4 s), multi-slice, echo planar acquisition, and approximately three- and six-fold higher for three-dimensional echo planar images acquired with isotropic resolutions of 0.7 and 0.55 mm, respectively. Improvements in parallel imaging performance (geometry factor) were up to around 1.5-fold with increasing acceleration factor, and improvements in fMRI detectability (temporal signal-to-noise ratio) were up to around four-fold depending on the distance to the coil. Although deeper lying structures may not benefit from the design, most fMRI questions pertain to the neocortex which lies within approximately 4 cm from the surface. These results suggest that the resolution of fMRI (at 7 T) can approximate levels that are closer to the spatial/temporal scale of the fundamental functional organization of the human cortex using a simple high-density coil design for high sensitivity. Copyright © 2012 John Wiley & Sons, Ltd.

Accumulation and transfer of contaminants in killer whales (Orcinus orca) from Norway: indications for contaminant metabolism.

PubMed

Wolkers, Hans; Corkeron, Peter J; Van Parijs, Sofie M; Similä, Tiu; Van Bavel, Bert

2007-08-01

Blubber tissue of one subadult and eight male adult killer whales was sampled in Northern Norway in order to assess the degree and type of contaminant exposure and transfer in the herring-killer whale link of the marine food web. A comprehensive selection of contaminants was targeted, with special attention to toxaphenes and polybrominated diphenyl ethers (PBDEs). In addition to assessing exposure and food chain transfer, selective accumulation and metabolism issues also were addressed. Average total polychlorinated biphenyl (PCB) and pesticide levels were similar, approximately 25 microg/g lipid, and PBDEs were approximately 0.5 microg/g. This makes killer whales one of the most polluted arctic animals, with levels exceeding those in polar bears. Comparing the contamination of the killer whale's diet with the diet of high-arctic species such as white whales reveals six to more than 20 times higher levels in the killer whale diet. The difference in contaminant pattern between killer whales and their prey and the metabolic index calculated suggested that these cetaceans have a relatively high capacity to metabolize contaminants. Polychlorinated biphenyls, chlordanes, and dichlorodiphenyldichloro-ethylene (DDE) accumulate to some degree in killer whales, although toxaphenes and PBDEs might be partly broken down.

Microbial destruction by low concentrations of hypochlorite and iodophor germicides in alkaline and acidified water.

PubMed

Hays, H; Elliker, P R; Sandine, W E

1967-05-01

Hypochlorite and iodophor germicides were evaluated for their ability to destroy a variety of organisms at levels approximating those used for final sanitizing rinse for dairy and food equipment and beverage bottles (3 to 50 ppm). Test organisms included Escherichia coli, Streptococcus lactis, Lactobacillus plantarum, Pediococcus cerevisiae, and Saccharomyces cerevisiae. The hypochlorites and iodophors demonstrated approximate rates of destruction at equivalent concentrations for the bacterial species tested, except where the hypochlorite contained excess alkalinity. The hypochlorite responded more readily to a downward shift to a pH of 5.0 than did the iodophor. Excess alkalinity of the hypochlorite significantly affected its bactericidal activity. The iodophor exhibited a consistently greater rate of destruction of yeast cells than the hypochlorite. Successive treatment with low levels of iodophor (6 ppm) followed by a hypochlorite (12 to 25 ppm) resulted in a high level of destruction of all test organisms. Possibilities for employing these measures in a sanitizing rinse of bottles for maximal destruction of organisms were discussed. Among the test organisms, S. lactis showed a comparatively high resistance and was a useful organism for comparing the halogen preparations.

Experimental Study of Vane Heat Transfer and Aerodynamics at Elevated Levels of Turbulence

NASA Technical Reports Server (NTRS)

Ames, Forrest E.

1994-01-01

A four vane subsonic cascade was used to investigate how free stream turbulence influences pressure surface heat transfer. A simulated combustor turbulence generator was built to generate high level (13 percent) large scale (Lu approximately 44 percent inlet span) turbulence. The mock combustor was also moved upstream to generate a moderate level (8.3 percent) of turbulence for comparison to smaller scale grid generated turbulence (7.8 percent). The high level combustor turbulence caused an average pressure surface heat transfer augmentation of 56 percent above the low turbulence baseline. The smaller scale grid turbulence produced the next greatest effect on heat transfer and demonstrated the importance of scale on heat transfer augmentation. In general, the heat transfer scaling parameter U(sub infinity) TU(sub infinity) LU(sub infinity)(exp -1/3) was found to hold for the turbulence. Heat transfer augmentation was also found to scale approximately on Re(sub ex)(exp 1/3) at constant turbulence conditions. Some evidence of turbulence intensification in terms of elevated dissipation rates was found along the pressure surface outside the boundary layer. However, based on the level of dissipation and the resulting heat transfer augmentation, the amplification of turbulence has only a moderate effect on pressure surface heat transfer. The flow field turbulence does drive turbulent production within the boundary layer which in turn causes the high levels of heat transfer augmentation. Unlike heat transfer, the flow field straining was found to have a significant effect on turbulence isotropy. On examination of the one dimensional spectra for u' and v', the effect to isotropy was largely limited to lower wavenumber spectra. The higher wavenumber spectra showed little or no change. The high level large scale turbulence was found to have a strong influence on wake development. The free stream turbulence significantly enhanced mixing resulting in broader and shallower wakes than the baseline case. High levels of flow field turbulence were found to correlate with a significant increase in total pressure loss in the core of the flow. Documenting the wake growth and characteristics provides boundary conditions for the downstream rotor.

Effective radiological contamination control and monitoring techniques in high alpha environments.

PubMed

Funke, Kevin C

2003-02-01

In the decommissioning of a highly contaminated alpha environment, such as the one at Hanford's 233-S Plutonium Concentration Facility, one of the key elements of a successful radiological control program is an integrated safety approach. This approach begins with the job-planning phase where the scope of the work is described. This is followed by a brainstorming session involving engineering and craft to identify how to perform the work in a logical sequence of events. Once the brainstorming session is over, a Job Hazard Analysis is performed to identify any potential problems. Mockups are utilized to enable the craft to get hands on experience and provide feedback and ideas to make the job run smoother. Ideas and experience gained during mockups are incorporated into the task instruction. To assure appropriate data are used in planning and executing the job, our principal evaluation tools included lapel and workplace air sampling, plus continuous air monitors and frequent surveys to effectively monitor job progress. In this highly contaminated alpha environment, with contamination levels ranging from 0.3 Bq cm-2 to approximately 100,000 Bq cm-2 (2,000 dpm per 100 cm2 to approximately 600 million dpm per 100 cm2), with average working levels of 1,600-3,200 Bq cm-2 (10-20 million dpm per 100 cm2) without concomitant ambient radiation levels, control of the spread of contamination is key to keeping airborne levels As Low As Reasonably Achievable.

Effective Radiological Contamination Control and Monitoring Techniques In High Alpha Environments.

PubMed

Funke, Kevin C.

2003-02-01

In the decommissioning of a highly contaminated alpha environment, such as the one at Hanford's 233-S Plutonium Concentration Facility, one of the key elements of a successful radiological control program is an integrated safety approach. This approach begins with the job-planning phase where the scope of the work is described. This is followed by a brainstorming session involving engineering and craft to identify how to perform the work in a logical sequence of events. Once the brainstorming session is over, a Job Hazard Analysis is performed to identify any potential problems. Mockups are utilized to enable the craft to get hands on experience and provide feedback and ideas to make the job run smoother. Ideas and experience gained during mockups are incorporated into the task instruction. To assure appropriate data are used in planning and executing the job, our principal evaluation tools included lapel and workplace air sampling, plus continuous air monitors and frequent surveys to effectively monitor job progress. In this highly contaminated alpha environment, with contamination levels ranging from 0.3 Bq cm to approximately 100,000 Bq cm (2,000 dpm per 100 cm to approximately 600 million dpm per 100 cm ), with average working levels of 1,600-3,200 Bq cm (10-20 million dpm per 100 cm ) without concomitant ambient radiation levels, control of the spread of contamination is key to keeping airborne levels As Low As Reasonably Achievable.

The relation between degree-2160 spectral models of Earth's gravitational and topographic potential: a guide on global correlation measures and their dependency on approximation effects

NASA Astrophysics Data System (ADS)

Hirt, Christian; Rexer, Moritz; Claessens, Sten; Rummel, Reiner

2017-10-01

Comparisons between high-degree models of the Earth's topographic and gravitational potential may give insight into the quality and resolution of the source data sets, provide feedback on the modelling techniques and help to better understand the gravity field composition. Degree correlations (cross-correlation coefficients) or reduction rates (quantifying the amount of topographic signal contained in the gravitational potential) are indicators used in a number of contemporary studies. However, depending on the modelling techniques and underlying levels of approximation, the correlation at high degrees may vary significantly, as do the conclusions drawn. The present paper addresses this problem by attempting to provide a guide on global correlation measures with particular emphasis on approximation effects and variants of topographic potential modelling. We investigate and discuss the impact of different effects (e.g., truncation of series expansions of the topographic potential, mass compression, ellipsoidal versus spherical approximation, ellipsoidal harmonic coefficient versus spherical harmonic coefficient (SHC) representation) on correlation measures. Our study demonstrates that the correlation coefficients are realistic only when the model's harmonic coefficients of a given degree are largely independent of the coefficients of other degrees, permitting degree-wise evaluations. This is the case, e.g., when both models are represented in terms of SHCs and spherical approximation (i.e. spherical arrangement of field-generating masses). Alternatively, a representation in ellipsoidal harmonics can be combined with ellipsoidal approximation. The usual ellipsoidal approximation level (i.e. ellipsoidal mass arrangement) is shown to bias correlation coefficients when SHCs are used. Importantly, gravity models from the International Centre for Global Earth Models (ICGEM) are inherently based on this approximation level. A transformation is presented that enables a transformation of ICGEM geopotential models from ellipsoidal to spherical approximation. The transformation is applied to generate a spherical transform of EGM2008 (sphEGM2008) that can meaningfully be correlated degree-wise with the topographic potential. We exploit this new technique and compare a number of models of topographic potential constituents (e.g., potential implied by land topography, ocean water masses) based on the Earth2014 global relief model and a mass-layer forward modelling technique with sphEGM2008. Different to previous findings, our results show very significant short-scale correlation between Earth's gravitational potential and the potential generated by Earth's land topography (correlation +0.92, and 60% of EGM2008 signals are delivered through the forward modelling). Our tests reveal that the potential generated by Earth's oceans water masses is largely unrelated to the geopotential at short scales, suggesting that altimetry-derived gravity and/or bathymetric data sets are significantly underpowered at 5 arc-min scales. We further decompose the topographic potential into the Bouguer shell and terrain correction and show that they are responsible for about 20 and 25% of EGM2008 short-scale signals, respectively. As a general conclusion, the paper shows the importance of using compatible models in topographic/gravitational potential comparisons and recommends the use of SHCs together with spherical approximation or EHCs with ellipsoidal approximation in order to avoid biases in the correlation measures.

Planar measurements of soot volume fraction and OH in a JP-8 pool fire

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henriksen, Tara L.; Ring, Terry A.; Eddings, Eric G.

2009-07-15

The simultaneous measurement of soot volume fraction by laser induced incandescence (LII) and qualitative imaging of OH by laser induced fluorescence (LIF) was performed in a JP-8 pool fire contained in a 152 mm diameter pan. Line of sight extinction was used to calibrate the LII system in a laminar flame, and to provide an independent method of measuring average soot volume fraction in the turbulent flame. The presence of soot in the turbulent flame was found to be approximately 50% probable, resulting in high levels of optical extinction, which increased slightly through the flame from approximately 30% near themore » base, to approximately 50% at the tip. This high soot loading pushes both techniques toward their detection limit. Nevertheless, useful accuracy was obtained, with the LII measurement of apparent extinction in the turbulent flame being approximately 21% lower than a direct measurement, consistent with the influence of signal trapping. The axial and radial distributions of soot volume fraction are presented, along with PDFs of volume fraction, and new insight into the behavior of soot sheets in pool fires are sought from the simultaneous measurements of OH and LII. (author)« less

Optical, IUE, and ROSAT observations of the eclipsing nova-like variable V347 Puppis (LB 1800)

NASA Technical Reports Server (NTRS)

Mauche, Christopher W.; Raymond, John C.; Buckley, David A. H.; Mouchet, Martine; Bonnell, Jerry; Sullivan, Denis J.; Bonnet-Bidaud, Jean-Marc; Bunk, Wolfram H.

1994-01-01

Using time-resolved optical spectroscopy and UBVRI and high-speed photometry obtained at Mount Stromlo Observatory, Mount John University Observatory, and the South African Astronomical Observatory; International Ultraviolet Explorer (IUE) ultraviolet spectroscopy; and Roentgen Satellite (ROSAT) survey X-ray fluxes, we present a study of the accretion disk, hot spot, and emission line regions in the bright eclipsing nova-like variable V347 Pup (LB 1800). In the optical and UV, V347 Pup is a strong emission line source with a continuum spectrum which is remarkably red for a high-M cataclysmic variable. Consistent with its high inclination, we interpret the continuum spectrum as the superposition of the spectrum of the cool (T(sub eff) approximately 7000 K) outer edge and the hot (T(sub eff) approximately 100,000 K) inner regions of a self-eclipsed accretion disk. For the assumed parameters, the model matches the level and shape of the observed spectrum for an inclination of approximately 88 and a distance of approximately 300 pc. The prominent hump in the optical and UV light curves just before eclipse manifests the presence of the hot spot where the accretion stream strikes the edge of the disk. The wavelength dependence of the amplitude of the hump is best modeled by a spot having an effective temperature of approximately 25,000 K and an area of approximately 3 x 10(exp 18) sq cm if the spot radiates like a blackbody, or an effective temperatue of approximately 14,000 K and an area of approximately 3 x 10(exp 19) sq cm if it radiates with a stellar spectrum. In either case, the hot spot produces only one-tenth of the predicted luminosity for the assumed mass-transfer rate of 10(exp -8) solar mass/yr. Either the hot spot is 'buried' in the edge of the accretion disk, or a significant fraction of its luminosity is radiated away in lines. The difference in azimuth between the peak of the hump and the dynamically expected location of the hot spot suggests that the spot's emitting surface is rotated forward by approximately 36 deg relative to the edge of the disk.

Optical, IUE, and ROSAT observations of the eclipsing nova-like variable V347 Puppis (LB 1800)

NASA Astrophysics Data System (ADS)

Mauche, Christopher W.; Raymond, John C.; Buckley, David A. H.; Mouchet, Martine; Bonnell, Jerry; Sullivan, Denis J.; Bonnet-Bidaud, Jean-Marc; Bunk, Wolfram H.

1994-03-01

Using time-resolved optical spectroscopy and UBVRI and high-speed photometry obtained at Mount Stromlo Observatory, Mount John University Observatory, and the South African Astronomical Observatory; International Ultraviolet Explorer (IUE) ultraviolet spectroscopy; and Roentgen Satellite (ROSAT) survey X-ray fluxes, we present a study of the accretion disk, hot spot, and emission line regions in the bright eclipsing nova-like variable V347 Pup (LB 1800). In the optical and UV, V347 Pup is a strong emission line source with a continuum spectrum which is remarkably red for a high-M cataclysmic variable. Consistent with its high inclination, we interpret the continuum spectrum as the superposition of the spectrum of the cool (Teff approximately 7000 K) outer edge and the hot (Teff approximately 100,000 K) inner regions of a self-eclipsed accretion disk. For the assumed parameters, the model matches the level and shape of the observed spectrum for an inclination of approximately 88 and a distance of approximately 300 pc. The prominent hump in the optical and UV light curves just before eclipse manifests the presence of the hot spot where the accretion stream strikes the edge of the disk. The wavelength dependence of the amplitude of the hump is best modeled by a spot having an effective temperature of approximately 25,000 K and an area of approximately 3 x 1018 sq cm if the spot radiates like a blackbody, or an effective temperatue of approximately 14,000 K and an area of approximately 3 x 1019 sq cm if it radiates with a stellar spectrum. In either case, the hot spot produces only one-tenth of the predicted luminosity for the assumed mass-transfer rate of 10-8 solar mass/yr. Either the hot spot is 'buried' in the edge of the accretion disk, or a significant fraction of its luminosity is radiated away in lines. The difference in azimuth between the peak of the hump and the dynamically expected location of the hot spot suggests that the spot's emitting surface is rotated forward by approximately 36 deg relative to the edge of the disk.

Family and Consumer Sciences and STEM Integration

ERIC Educational Resources Information Center

Carter, Vinson; Beachner, Maggie; Daugherty, Michael K.

2015-01-01

Family and consumer sciences (FCS) education has traditionally attracted a large percentage of female students (Vincenti, 1997; Werhan, 2013). Werhan (2013) reported that slightly less than 3.5 million students are engaged in FCS courses, and at the high school level, approximately 65% of them are female. This skewed representation of female…

RAMAN ANALYSIS OF FERTILIZER AND PLANT TISSUE EXTRACTS FOR PERCHLORATE CONTAMINATION

EPA Science Inventory

Recently, we and others found perchlorate at high levels (approximately 500 - 8000 mg/kg) in ~ 90% of 25+ fertilizers products (primarily lawn-and-garden type) with no known link to mined nitrate-bearing Chilean ore. This ore is used, albeit in small scale, in fertilizer product...

Strings in General Music: An Experience with Multiple Sequencing

ERIC Educational Resources Information Center

Martin, Jeffrey

2012-01-01

Instrumental performance that approximates real-world models is one way in which a general music curriculum can encourage high levels of engagement and potential for lifelong musical activity. Although guitars, keyboards, and various folk instruments are useful for this purpose, orchestral instruments can also provide significant solo and ensemble…

Environmental Contamination: Lessons Learned from the Cleanup of Formerly Used Defense and Military Munitions Sites

DTIC Science & Technology

2009-06-01

and is highly soluble. Exposure to perchlorate affects the human thyroid, and certain levels of exposure may result in hyperthyroidism in adults...resources conservation, and pollution prevention activities. In fiscal year 2007, DOD obligated approximately $4 billion for environmental activities, but

Raising the Bar

ERIC Educational Resources Information Center

Wells, Bryan D.; Gambero, Lori; Allen, Michael; Juarez, Alejandro

2012-01-01

The Fresno (California) Unified School District has one of the highest poverty levels in the nation. The district is made up of approximately 84% Hispanic students, and 70% of their parents speak only Spanish in the home. Many students have difficulty passing the California High School Exit Examination (CAHSEE), which is required to receive a…

The Full-Scale Implementation of an Innovative Biological Ammonia Treatment Process

EPA Science Inventory

Across the United States, high levels of ammonia in drinking water sources can be found, including small communities like Palo, Iowa (approximate population of 1,026). Although ammonia in water does not pose a direct health concern, ammonia nitrification can cause a number of iss...

High levels of genetic diversity in Spodoptera exempta NPV from Tanzania.

PubMed

Redman, Elizabeth M; Wilson, Kenneth; Grzywacz, David; Cory, Jenny S

2010-10-01

The African armyworm, Spodoptera exempta, is a major pest in sub-Saharan Africa. A nucleopolyhedrovirus (NPV) is often recorded in later population outbreaks and can cause very high levels of mortality. Research has been addressing whether this NPV can be developed into a strategic biological control agent. As part of this study, the variation in natural populations of NPV is being studied. An isolate of S. exempta NPV was cloned in vivo and found to contain at least 17 genetically-distinct genotypes. These genotypes varied in size from approximately 115 to 153 kb. Copyright 2010 Elsevier Inc. All rights reserved.

Environment and genotype effects on the content of dietary fiber and its components in wheat in the HEALTHGRAIN diversity screen.

PubMed

Gebruers, Kurt; Dornez, Emmie; Bedõ, Zoltan; Rakszegi, Mariann; Frás, Anna; Boros, Danuta; Courtin, Christophe M; Delcour, Jan A

2010-09-08

Within the HEALTHGRAIN diversity screen, the variability of the contents of dietary fiber (DF) and components thereof was studied in wheat. Furthermore, the contribution of genotype and environment to this variability was estimated. The levels of total DF (TDF), total nonstarch polysaccharide (TOTNSP), water-extractable nonstarch polysaccharide (WENSP), total arabinoxylan (TOTAX), lignin, and beta-glucan in whole meal, flour, and/or bran varied approximately 1.8-fold. The highest variability was observed for the water-extractable arabinoxylan (WEAX) level in flour and bran (approximately 3.7-fold). Genotype and environment contributed to a similar extent to the variability in TDF, TOTNSP, and TOTAX content in wheat. The observed relatively high impact of genotype-environment interaction suggests that the levels of these constituents are weak breeding parameters. The WENSP level is a more stable parameter as the effect of the interaction term was much less than the impact of genotype. For TOTAX and WEAX in flour, WEAX in bran, beta-glucan in whole meal, and extract viscosity, wheat genotype determined approximately 50% or higher of the variation observed, whereas the impact of the genotype-environment interaction was relatively low. These findings suggest that the health-related and technological functionality of wheat can be directed to a certain extent by selection of appropriate wheat varieties.

Life after School: A Profile of Early Leavers in Newfoundland. Youth Transition into the Labour Market. Report and Summary Report.

ERIC Educational Resources Information Center

Spain, William H.; And Others

This project consists of two parallel yet interrelated studies, one focusing on the full cohort of approximately 9,000 Level III (Grade 12) high school students in Newfoundland and Labrador at the end of the 1988-89 school year, and a second, which focuses on the full year cohort of 2109 students (grades seven to Level III) who dropped out of…

Light Moderates the Induction of Phosphoenolpyruvate Carboxylase by NaCl and Abscisic Acid in Mesembryanthemum crystallinum 1

PubMed Central

McElwain, Elizabeth F.; Bohnert, Hans J.; Thomas, John C.

1992-01-01

In Mesembryanthemum crystallinum, phosphoenolpyruvate carboxylase is synthesized de novo in response to osmotic stress, as part of the switch from C3-photosynthesis to Crassulacean acid metabolism. To better understand the environmental signals involved in this pathway, we have investigated the effects of light on the induced expression of phosphoenolpyruvate carboxylase mRNA and protein in response to stress by 400 millimolar NaCl or 10 micromolar abscisic acid in hydroponically grown plants. When plants were grown in high-intensity fluorescent or incandescent light (850 microeinsteins per square meter per second), NaCl and abscisic acid induced approximately an eightfold accumulation of phosphoenolpyruvate carboxylase mRNA when compared to untreated controls. Levels of phosphoenolpyruvate carboxylase protein were high in these abscisic acid- and NaCl-treated plants, and detectable in the unstressed control. Growth in high-intensity incandescent (red) light resulted in approximately twofold higher levels of phosphoenolpyruvate carboxylase mRNA in the untreated plants when compared to control plants grown in high-intensity fluorescent light. In low light (300 microeinsteins per square meter per second fluorescent), only NaCl induced mRNA levels significantly above the untreated controls. Low light grown abscisic acid- and NaCl-treated plants contained a small amount of phosphoenolpyruvate carboxylase protein, whereas the (untreated) control plants did not contain detectable amounts of phosphoenolpyruvate carboxylase. Environmental stimuli, such as light and osmotic stress, exert a combined effect on gene expression in this facultative halophyte. ImagesFigure 1Figure 2 PMID:16668999

Seasonal variability of salinity, temperature, turbidity and suspended chlorophyll in the Tweed Estuary.

PubMed

Uncles, R J; Bloomer, N J; Frickers, P E; Griffiths, M L; Harris, C; Howland, R J; Morris, A W; Plummer, D H; Tappin, A D

2000-05-05

Results are presented from a campaign of measurements that were undertaken to examine seasonal variability in physical and chemical fluxes and processes within the Tweed Estuary during the period September 1996-August 1997. The study utilised monthly surveys, each of approximately 1 week duration. This article interprets a subset of the salinity, temperature, turbidity [suspended particulate matter (SPM) levels] and chlorophyll a data. Measurements discussed here were obtained throughout the estuary during high-speed transects that covered the region between the tidal river and the coastal zone. Longitudinal distributions of surface salinity depended strongly on freshwater runoff. During high runoff the surface salinity was low and the freshwater-saltwater interface (FSI) was located close to the mouth. The reverse was true at times of low runoff. Salinity stratification was generally strong. During the surveys, river runoff temperatures ranged from approximately 2 to 18 degrees C and coastal waters (approximately 33 salinity) from approximately 6 to 15 degrees C. Turbidity was low throughout the campaign (SPM < 30 mg l(-1)). Because of rapid flushing times (one or two tides), turbidity tended to mix conservatively between river and coastal waters. Higher coastal turbidity was associated with stronger wind events, and higher fluvial turbidity with spate events. Suspended chlorophyll a levels were usually low throughout the estuary (typically < 2 microg l(-1)) and showed large spatial variability. Because of the rapid flushing of the estuary, it is hypothesised that it was not possible for several algal cell divisions to occur before algae were flushed to the coastal zone. A 'bloom' occurred during the May 1997 survey, when chlorophyll a levels reached 14 microg l(-1). Higher chlorophyll a concentrations at that time occurred at very low salinities, indicating that these waters and algae were largely fluvially derived, and may have resulted from increasing springtime solar irradiation.

The coral reef crisis: the critical importance of<350 ppm CO2.

PubMed

Veron, J E N; Hoegh-Guldberg, O; Lenton, T M; Lough, J M; Obura, D O; Pearce-Kelly, P; Sheppard, C R C; Spalding, M; Stafford-Smith, M G; Rogers, A D

2009-10-01

Temperature-induced mass coral bleaching causing mortality on a wide geographic scale started when atmospheric CO(2) levels exceeded approximately 320 ppm. When CO(2) levels reached approximately 340 ppm, sporadic but highly destructive mass bleaching occurred in most reefs world-wide, often associated with El Niño events. Recovery was dependent on the vulnerability of individual reef areas and on the reef's previous history and resilience. At today's level of approximately 387 ppm, allowing a lag-time of 10 years for sea temperatures to respond, most reefs world-wide are committed to an irreversible decline. Mass bleaching will in future become annual, departing from the 4 to 7 years return-time of El Niño events. Bleaching will be exacerbated by the effects of degraded water-quality and increased severe weather events. In addition, the progressive onset of ocean acidification will cause reduction of coral growth and retardation of the growth of high magnesium calcite-secreting coralline algae. If CO(2) levels are allowed to reach 450 ppm (due to occur by 2030-2040 at the current rates), reefs will be in rapid and terminal decline world-wide from multiple synergies arising from mass bleaching, ocean acidification, and other environmental impacts. Damage to shallow reef communities will become extensive with consequent reduction of biodiversity followed by extinctions. Reefs will cease to be large-scale nursery grounds for fish and will cease to have most of their current value to humanity. There will be knock-on effects to ecosystems associated with reefs, and to other pelagic and benthic ecosystems. Should CO(2) levels reach 600 ppm reefs will be eroding geological structures with populations of surviving biota restricted to refuges. Domino effects will follow, affecting many other marine ecosystems. This is likely to have been the path of great mass extinctions of the past, adding to the case that anthropogenic CO(2) emissions could trigger the Earth's sixth mass extinction.

High-throughput and rapid quantification of lipids by nanoflow UPLC-ESI-MS/MS: application to the hepatic lipids of rabbits with nonalcoholic fatty liver disease.

PubMed

Byeon, Seul Kee; Lee, Jong Cheol; Chung, Bong Chul; Seo, Hong Seog; Moon, Myeong Hee

2016-07-01

A rapid and high-throughput quantification method (approximately 300 lipids within 20 min) was established using nanoflow ultrahigh-pressure liquid chromatography-tandem mass spectrometry (nUPLC-ESI-MS/MS) with selective reaction monitoring (SRM) and applied to the quantitative profiling of the hepatic lipids of rabbits with different metabolic conditions that stimulate the development of nonalcoholic fatty liver disease (NAFLD). Among the metabolic conditions of rabbits in this study [inflammation (I), high-cholesterol diet (HC), and high-cholesterol diet combined with inflammation (HCI)], significant perturbation in hepatic lipidome (>3-fold and p < 0.01) was observed in the HC and HCI groups, while no single lipid showed a significant change in group I. In addition, this study revealed a dramatic increase (>2-fold) in relatively high-abundant monohexosylceramides (MHCs), sphingomyelins (SMs), and triacylglycerols (TGs) in both the HC and HCI groups, especially in MHCs as all 11 MHCs increased by larger than 3- to 12-fold. As the levels of the relatively high-abundant lipids in the above classes increased, the total lipidome level of each class increased significantly by approximately 2-fold to 5-fold. Other classes of lipids also generally increased, which was likely induced by the increase in mitogenic and nonapoptotic MHCs and SMs, as they promote cell proliferation. On the other hand, a slight decrease in the level of apoptotic ceramides (Cers) was observed, which agreed with the general increase in total lipid level. As distinct changes in hepatic lipidome were observed from HC groups, this suggests that HC or HCI is highly associated with NAFLD but not inflammation alone itself. Graphical Abstract Schematic of lipidomic analysis from hepatic tissue using nanoflow LC-ESI-MS/MS and nUPLC-ESI-MS/MS.

Topics in electron capture by fast ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsin, S.H.

1987-01-01

The post-collision interaction (PCI) model was applied, together with the eikonal approximation, to study the (n = 2,3) capture cross sections in p + H(ls) collisions. The results indeed improve the previous eikonal calculations for l = 0 cases, and agree quite well with present experimental data. Calculations using the strong-potential Born (SPB) approximation, with the Sil and McGuire technique, for capture into the np, nd levels are also presented. While these cross sections are smaller than cross sections for capture into the ns levels at high velocities, nevertheless the Thomas peak is clearly evident in both the absolute valuemore » m = 2, absolute value m = 1 and m = 0 magnetic substates in p + H(ls) collisions. Also calculated were corrections to the SPB using the Distorted-Wave Born formalism of Taulbjerg and Briggs. In the sense of a plane-wave Born expansion, all terms of the third Born approximation and all single switching fourth Born terms are included, but a peaking approximation is needed to reduce the calculation to tractable form. Effects of the higher terms are most visible in the valley between the Thomas peak and the forward peak. The Thomas peak is visible in the correction term, even though it includes no second Born contributions.« less

Improved High/Low Junction Silicon Solar Cell

NASA Technical Reports Server (NTRS)

Neugroschel, A.; Pao, S. C.; Lindholm, F. A.; Fossum, J. G.

1986-01-01

Method developed to raise value of open-circuit voltage in silicon solar cells by incorporating high/low junction in cell emitter. Power-conversion efficiency of low-resistivity silicon solar cell considerably less than maximum theoretical value mainly because open-circuit voltage is smaller than simple p/n junction theory predicts. With this method, air-mass-zero opencircuit voltage increased from 600 mV level to approximately 650 mV.

Climatology of the winter Red Sea Trough

NASA Astrophysics Data System (ADS)

Awad, Adel M.; Almazroui, Mansour

2016-12-01

In this study, a new and objective method for detecting the Red Sea Trough (RST) was developed using mean sea level pressure (SLP) data from NCEP/NCAR reanalysis dataset from the winters of 1956 to 2015 to identify the Sudan Low and its trough. Approximately 96% of the winter RSTs were generated near two main sources, South Sudan and southeastern Sudan, and approximately 85% of these troughs were in four of the most outer areas surrounding the northern Red Sea. Moreover, from west to east of the Red Sea, the RST was affected by the relationships between the Siberian High and Azores High. The RST was oriented to the west when the strength of the Siberian High increased and to the east when the strength of the Azores High increased. Furthermore, the synoptic features of the upper level of the RST emphasize the impacts of subtropical anticyclones at 850 hPa on the orientation of the RST, the impacts of the northern cyclone trough and the maximum wind at a pressure level of 250 hPa. The average static stability between 1000 hPa and 500 hPa demonstrated that the RST followed the northern areas of low static stability. The results from previous studies were confirmed by a detailed case study of the RST that extended to its central outermost area. The results of a detailed case study of the short RST indicated that the trough becomes shorter with increasing static stability and that the Azores and Siberian high-pressure systems influence the northern region of the trough while the maximum upper wind shifts south of the climate position.

Utilising shade to optimize UV exposure for vitamin D

NASA Astrophysics Data System (ADS)

Turnbull, D. J.; Parisi, A. V.

2008-06-01

Numerous studies have stated that humans need to utilise full sun radiation, at certain times of the day, to assist the body in synthesising the required levels of vitamin D3. The time needed to be spent in the full sun depends on a number of factors, for example, age, skin type, latitude, solar zenith angle. Current Australian guidelines suggest exposure to approximately 1/6 to 1/3 of a minimum erythemal dose (MED), depending on age, would be appropriate to provide adequate vitamin D3 levels. The aim of the study was to determine the exposure times to diffuse solar UV to receive exposures of 1/6 and 1/3 MED for a changing solar zenith angle in order to assess the possible role that diffuse UV (scattered radiation) may play in vitamin D3 effective UV exposures (UVD3). Diffuse and global erythemal UV measurements were conducted at five minute intervals over a twelve month period for a solar zenith angle range of 4° to 80° at a latitude of 27.6° S. For a diffuse UV exposure of 1/3 MED, solar zenith angles smaller than approximately 50° can be utilised for exposure times of less than 10 min. Spectral measurements showed that, for a solar zenith angle of 40°, the UVA (315-400 nm) in the diffuse component of the solar UV is reduced by approximately 62% compared to the UVA in the global UV, whereas UVD3 wavelengths are only reduced by approximately 43%. At certain latitudes, diffuse UV under shade may play an important role in providing the human body with adequate levels of UVD3 (290-315 nm) radiation without experiencing the high levels of UVA observed in full sun.

Ambient lead measurements in Cairo, Egypt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howes, J.E. Jr.; Labib, M.; Samaha, N.

1999-07-01

The Cairo Air Improvement Project (CAIP) has established a network of 36 stations to monitor airborne lead levels in the Greater Cairo Area. Data obtained during the first 4 months of the monitoring program indicates that lead levels in ambient air significantly exceed the Government of Egypt's (GOE) Law Number 4 (1994) limit of 1 {micro} g/m{sup 3} (annual mean) in areas downwind of secondary lead smelters and in heavily trafficked areas. The highest mean and single sampling event lead levels were observed in the heavily industrialized areas of Shoubra el-Kheima and Tebbin. At two sites in Shoubra el-Kheima, meanmore » and maximum lead levels were determined to be approximately 20 {micro} g/m{sup 3} and 79 {micro} g/m{sup 3}, respectively. At three sites located in areas of high motor vehicle traffic in the central part of the city, the mean lead level was about 4 {micro} g/m{sup 3} and the maximum levels ranged from approximately 10 x 20 {micro} g/m{sup 3}. Of the remainder of the sites, the mean lead concentrations were 2fd3 {micro} g/m{sup 3} at three sites, 1 P2 {mu} g/m{sup 3} at 16 sites, and below 1 {micro} g/m{sup 3} at eight sites. Lead levels in areas devoted primarily to residential use were generally less than 2 {micro} g/m{sup 3}. The maximum mean monthly PM{sub 10} lead value measured at fugitive emission monitoring sites near lead smelters was approximately 73 {micro} g/m{sup 3}. The maximum lead concentration measured during a single sampling event was 180 {micro} g/m{sup 3}. Generally lower lead levels were observed in December due to regulation action that resulted in some suspension of smelting operations and to approximately 180-degree wind direction shifts that typically occur during this period of the year. The GOE is working vigorously to eliminate the lead problem in Egypt through implementation of the Lead Exposure Action Plan (LEAP). A major component of LEAP is the Lead Smelter Action Plan (LSAP).« less

Determination of the N2 recombination rate coefficient in the ionosphere

NASA Technical Reports Server (NTRS)

Orsini, N.; Torr, D. G.; Brinton, H. C.; Brace, L. H.; Hanson, W. B.; Hoffman, J. H.; Nier, A. O.

1977-01-01

Measurements of aeronomic parameters made by the Atmosphere Explorer-C satellite are used to determine the recombination rate coefficient of N2(+) in the ionosphere. The rate is found to increase significantly with decreasing electron density. Values obtained range from approximately 1.4 x 10 to the -7th to 3.8 x 10 to the -7th cu cm/sec. This variation is explained in a preliminary way in terms of an increase in the rate coefficient with vibrational excitation. Thus, high electron densities depopulate high vibrational levels reducing the effective recombination rate, whereas, low electron densities result in an enhancement in the population of high vibrational levels, thus, increasing the effective recombination rate.

High-level expression of human immunodeficiency virus antigens from the tobacco and tomato plastid genomes.

PubMed

Zhou, Fei; Badillo-Corona, Jesus A; Karcher, Daniel; Gonzalez-Rabade, Nuria; Piepenburg, Katrin; Borchers, A-M Inka; Maloney, Alan P; Kavanagh, Tony A; Gray, John C; Bock, Ralph

2008-12-01

Transgene expression from the plant's plastid genome represents a promising strategy in molecular farming because of the plastid's potential to accumulate foreign proteins to high levels and the increased biosafety provided by the maternal mode of organelle inheritance. In this article, we explore the potential of transplastomic plants to produce human immunodeficiency virus (HIV) antigens as potential components of an acquired immunodeficiency syndrome (AIDS) vaccine. It is shown that the HIV antigens p24 (the major target of T-cell-mediated immune responses in HIV-positive individuals) and Nef can be expressed to high levels in plastids of tobacco, a non-food crop, and tomato, a food crop with an edible fruit. Optimized p24-Nef fusion gene cassettes trigger antigen protein accumulation to up to approximately 40% of the plant's total protein, demonstrating the great potential of transgenic plastids to produce AIDS vaccine components at low cost and high yield.

Using Biweight M-Estimates in the Two-Sample Problem. 1. Symmetric Populations

DTIC Science & Technology

1982-01-01

to a Student’s t distribution, across a broad range of a - levels . To be conservative, we might wish to approximate "t" by a Student’s t on nine-tenths...n-i0). While the robustness of classical procedures for extreme a - levels has not been investigated, a comparison with the values in Lee and...D’Agostino (1976) indicates that this procedure is highly robust of validity at a - .05, presumably this robustness extends to the extreme a - levels as well

Polar firn air reveals large-scale impact of anthropogenic mercury emissions during the 1970s.

PubMed

Faïn, Xavier; Ferrari, Christophe P; Dommergue, Aurélien; Albert, Mary R; Battle, Mark; Severinghaus, Jeff; Arnaud, Laurent; Barnola, Jean-Marc; Cairns, Warren; Barbante, Carlo; Boutron, Claude

2009-09-22

Mercury (Hg) is an extremely toxic pollutant, and its biogeochemical cycle has been perturbed by anthropogenic emissions during recent centuries. In the atmosphere, gaseous elemental mercury (GEM; Hg degrees ) is the predominant form of mercury (up to 95%). Here we report the evolution of atmospheric levels of GEM in mid- to high-northern latitudes inferred from the interstitial air of firn (perennial snowpack) at Summit, Greenland. GEM concentrations increased rapidly after World War II from approximately 1.5 ng m(-3) reaching a maximum of approximately 3 ng m(-3) around 1970 and decreased until stabilizing at approximately 1.7 ng m(-3) around 1995. This reconstruction reproduces real-time measurements available from the Arctic since 1995 and exhibits the same general trend observed in Europe since 1990. Anthropogenic emissions caused a two-fold rise in boreal atmospheric GEM concentrations before the 1970s, which likely contributed to higher deposition of mercury in both industrialized and remotes areas. Once deposited, this toxin becomes available for methylation and, subsequently, the contamination of ecosystems. Implementation of air pollution regulations, however, enabled a large-scale decline in atmospheric mercury levels during the 1980s. The results shown here suggest that potential increases in emissions in the coming decades could have a similar large-scale impact on atmospheric Hg levels.

Assessment of the levels of hexachlorocyclohexane in blood samples from Mexico.

PubMed

Trejo-Acevedo, Antonio; Rivero-Pérez, Norma Edith; Flores-Ramirez, Rogelio; Orta-García, Sandra Teresa; Pruneda-Álvarez, Lucia Guadalupe; Pérez-Maldonado, Iván N

2012-06-01

The aim of this study was to evaluate hexachlorocyclohexane (HCH) exposure in children living in nine hot spots in four Mexican states. We analyzed HCH (α, β, and γ-isomers) in blood using gas chromatography/mass spectrometry. HCH exposure level in 261 children was assessed and approximately 75 % of the children studied had detectable levels of HCH. These levels ranged from 188 to 40,096.7 ng/g lipid. The highest mean levels were found in Lacanja (5,446.9 ng/g lipid), an indigenous community in Chiapas, Mexico. Our data indicate high exposure to HCH in children living in these communities.

Population PK-PD analyses of CD25 occupancy, CD56bright NK cell expansion, and regulatory T cell reduction by daclizumab HYP in subjects with multiple sclerosis.

PubMed

Diao, Lei; Hang, Yaming; Othman, Ahmed A; Mehta, Devangi; Amaravadi, Lakshmi; Nestorov, Ivan; Tran, Jonathan Q

2016-11-01

Daclizumab high yield process (HYP) is a humanized IgG1 monoclonal antibody that binds to the α-subunit of the interleukin-2 receptor and is being developed for treatment of multiple sclerosis (MS). This manuscript characterized the pharmacokinetic-pharmacodynamic (PK-PD) relationships of daclizumab HYP in subjects with MS. Approximately 1400 subjects and 7000 PD measurements for each of three biomarkers [CD25 occupancy, CD56 bright natural killer (NK) cell count, regulatory T cell (Treg) count] from four clinical trials were analyzed using non-linear mixed effects modelling. Evaluated regimens included 150 or 300 mg subcutaneous (s.c.) every 4 weeks. CD25 occupancy was characterized using a sigmoidal maximum response (E max ) model. Upon daclizumab HYP treatment, CD25 saturation was rapid with complete saturation occurring after approximately 7 h and maintained when daclizumab HYP serum concentration was ≥5 mg l -1 . After the last 150 mg s.c. dose, unoccupied CD25 returned to baseline levels in approximately 24 weeks, with daclizumab HYP serum concentration approximately ≤1 mgl -1 1L. CD56 bright NK cell expansion was characterized using an indirect response model. Following daclizumab HYP 150 mg s.c. every 4 weeks, expansion plateaus approximately at week 36, at which the average maximum expansion ratio is 5.2. After the last dose, CD56 bright NK cells gradually declined to baseline levels within 24 weeks. Treg reduction was characterized by a sigmoidal E max model. Average maximum reduction of 60% occurred approximately 4 days post 150 mg s.c. dose. After the last dose, Tregs were projected to return to baseline levels in approximately 20 weeks. Robust PK-PD models of CD25 occupancy, CD56 bright NK cell expansion and Treg reduction by daclizumab HYP were developed to characterize its key pharmacodynamic effects in the target patient population. © 2016 The British Pharmacological Society.

Multilevel effects on the balance of dipole-allowed to dipole-forbidden transitions in Rydberg atoms induced by a dipole interaction with slow charged projectiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syrkin, M.I.

1996-02-01

In collisions of Rydberg atoms with charged projectiles at velocities approximately matching the speed of the Rydberg electron {ital v}{sub {ital n}} (matching velocity), {ital n} being the principal quantum number of the Rydberg level, the dipole-forbidden transitions with large angular-momentum transfer {Delta}{ital l}{gt}1 substantially dominate over dipole-allowed transitions {Delta}{ital l}=1, although both are induced by the dipole interaction. Here it is shown that as the projectile velocity decreases the adiabatic character of the depopulation depends on the energy distribution of states in the vicinity of the initial level. If the spectrum is close to degeneracy (as for high-{ital l}more » levels) the dipole-forbidden depopulation prevails practically over the entire low-velocity region, down to velocities {approximately}{ital n}{sup 3}[{Delta}{ital E}/Ry]{ital v}{sub {ital n}}, where {Delta}{ital E} is the energy spacing adjoining to the level due to either a quantum defect or the relevant level width or splitting, whichever is greater. If the energy gaps are substantial (as for strongly nonhydrogenic {ital s} and {ital p} levels in alkali-metal atoms), then the fraction of dipole transitions in the total depopulation reaches a flat minimum just below the matching velocity and then grows again, making the progressively increasing contribution to the low-velocity depopulation. The analytic models based on the first-order Born amplitudes (rather than the two-level adiabatic approximation) furnish reasonable estimates of the fractional dipole-allowed and dipole-forbidden depopulations. {copyright} {ital 1996 The American Physical Society.}« less

Abdominal obesity and physical inactivity are associated with erectile dysfunction independent of body mass index.

PubMed

Janiszewski, Peter M; Janssen, Ian; Ross, Robert

2009-07-01

Erectile dysfunction (ED) is common among men with an elevated body mass index (BMI). However, a high waist circumference (WC) and low levels of physical activity may predict ED independently of BMI. We investigated the independent relationships between BMI, WC, and physical activity with ED. Subjects consisted of 3,941 adult men (age > or = 20 years) with no history of prostate cancer from the 2001-2004 National Health and Nutrition Examination Survey. Logistic regression analyses were used to examine the relative odds of ED association with categories of BMI, WC, and physical activity. Established thresholds were used to divide subjects into three WC and BMI categories. Physical activity level was divided into active (> or =150 min/week), moderately active (30-149 min/week), and inactive (<30 min/week) categories. A single survey question was used to assess the presence of ED. After control for potential confounders, men with either a high WC or an obese BMI had an approximately 50% higher odds of having ED compared with men with a low WC or a normal BMI, respectively. Further, moderately active or inactive men had an approximately 40-60% greater odds of ED compared with active men. When all three predictors (WC, BMI, and physical activity level) were entered into the same logistic regression model, both a high WC and low physical activity level (moderately active and inactive) were independently associated with a greater odds of ED, whereas BMI level was not. Maintaining a WC level below 102 cm and achieving the recommended amount of moderate-intensity physical activity (>or =150 min/week) is associated with the maintenance of proper erectile function, regardless of BMI level. These findings suggest that the clinical screening for ED risk should include the assessment of WC and physical activity level in addition to BMI.

Benchmarking Hydrogen and Carbon NMR Chemical Shifts at HF, DFT, and MP2 Levels.

PubMed

Flaig, Denis; Maurer, Marina; Hanni, Matti; Braunger, Katharina; Kick, Leonhard; Thubauville, Matthias; Ochsenfeld, Christian

2014-02-11

An extensive study of error distributions for calculating hydrogen and carbon NMR chemical shifts at Hartree-Fock (HF), density functional theory (DFT), and Møller-Plesset second-order perturbation theory (MP2) levels is presented. Our investigation employs accurate CCSD(T)/cc-pVQZ calculations for providing reference data for 48 hydrogen and 40 carbon nuclei within an extended set of chemical compounds covering a broad range of the NMR scale with high relevance to chemical applications, especially in organic chemistry. Besides the approximations of HF, a variety of DFT functionals, and conventional MP2, we also present results with respect to a spin component-scaled MP2 (GIAO-SCS-MP2) approach. For each method, the accuracy is analyzed in detail for various basis sets, allowing identification of efficient combinations of method and basis set approximations.

Quantitative measurement of zinc secretion from pancreatic islets with high temporal resolution using droplet-based microfluidics.

PubMed

Easley, Christopher J; Rocheleau, Jonathan V; Head, W Steven; Piston, David W

2009-11-01

We assayed glucose-stimulated insulin secretion (GSIS) from live, murine islets of Langerhans in microfluidic devices by the downstream formation of aqueous droplets. Zinc ions, which are cosecreted with insulin from beta-cells, were quantitatively measured from single islets with high temporal resolution using a fluorescent indicator, FluoZin-3. Real-time storage of secretions into droplets (volume of 0.470 +/- 0.009 nL) effectively preserves the temporal chemical information, allowing reconstruction of the secretory time record. The use of passive flow control within the device removes the need for syringe pumps, requiring only a single hand-held syringe. Under stimulatory glucose levels (11 mM), bursts of zinc as high as approximately 800 fg islet(-1) min(-1) were measured. Treatment with diazoxide effectively blocked zinc secretion, as expected. High temporal resolution reveals two major classes of oscillations in secreted zinc, with predominate periods at approximately 20-40 s and approximately 5-10 min. The more rapid oscillation periods match closely with those of intraislet calcium oscillations, while the slower oscillations are consistent with insulin pulses typically measured in bulk islet experiments or in the bloodstream. This droplet sampling technique should be widely applicable to time-resolved cellular secretion measurements, either in real-time or for postprocessing.

NOx profile around a signalized intersection of busy roadway

NASA Astrophysics Data System (ADS)

Kim, Kyung Hwan; Lee, Seung-Bok; Woo, Sung Ho; Bae, Gwi-Nam

2014-11-01

The NOx pollution profile around a signalized intersection of a busy roadway was investigated to understand the effect of traffic control on urban air pollution. Traffic flow patterns were classified into three categories of quasi-cruising, a combination of deceleration and acceleration, and a combination of deceleration, idling, and acceleration. The spatial distribution of air pollution levels around an intersection could be represented as a quasi-normal distribution, whose peak height was aggravated by increased emissions due to transient driving patterns. The peak concentration of NOx around the signalized intersection for the deceleration, idling, and acceleration category was five times higher than that for the quasi-cruising category. Severe levels of NOx pollution tailed off approximately 400 m from the center of the intersection. Approximately 200-1000 ppb of additional NOx was observed when traffic was decelerating, idling, and accelerating within the intersection zone, resulting in high exposure levels for pedestrians around the intersection. We propose a fluctuating horizontal distribution of motor vehicle-induced air pollutants as a function of time.

Transmissivity and storage coefficient estimates from slug tests, Naval Air Warfare Center, West Trenton, New Jersey

USGS Publications Warehouse

Fiore, Alex R.

2014-01-01

Slug tests were conducted on 56 observation wells open to bedrock at the former Naval Air Warfare Center (NAWC) in West Trenton, New Jersey. Aquifer transmissivity (T) and storage coefficient (S) values for most wells were estimated from slug-test data using the Cooper-Bredehoeft-Papadopulos method. Test data from three wells exhibited fast, underdamped water-level responses and were analyzed with the Butler high-K method. The range of T at NAWC was approximately 0.07 to 10,000 square feet per day. At 11 wells, water levels did not change measurably after 20 minutes following slug insertion; transmissivity at these 11 wells was estimated to be less than 0.07 square feet per day. The range of S was approximately 10-10 to 0.01, the mode being 10-10. Water-level responses for tests at three wells fit poorly to the type curves of both methods, indicating that these methods were not appropriate for adequately estimating T and S from those data.

Digital-model simulation of the glacial-outwash aquifer, Otter Creek-Dry Creek basin, Cortland County, New York

USGS Publications Warehouse

Cosner, O.J.; Harsh, J.F.

1978-01-01

The city of Cortland, New York, and surrounding areas obtain water from the highly productive glacial-outwash aquifer underlying the Otter Creek-Dry Creek basin. Pumpage from the aquifer in 1976 was approximately 6.3 million gallons per day and is expected to increase as a result of population growth and urbanization. A digital ground-water model that uses a finite-difference approximation technique to solve partial differential equations of flow through a porous medium was used to simulate the movement of water within the aquifer. The model was calibrated to equilibrium conditions by comparing water levels measured in the aquifer in March 1976 with those computed by the model. Then, from the simulated water-level surface for March, a transient-condition run was made to simulate the surface as measured in September 1976. Computed water levels presented as contours are generally in close agreement with potentiometric-surface maps prepared from field measurements of March and September 1976. (Woodard-USGS)

Correction of the near threshold behavior of electron collisional excitation cross-sections in the plane-wave Born approximation

DOE PAGES

Kilcrease, D. P.; Brookes, S.

2013-08-19

The modeling of NLTE plasmas requires the solution of population rate equations to determine the populations of the various atomic levels relevant to a particular problem. The equations require many cross sections for excitation, de-excitation, ionization and recombination. Additionally, a simple and computational fast way to calculate electron collisional excitation cross-sections for ions is by using the plane-wave Born approximation. This is essentially a high-energy approximation and the cross section suffers from the unphysical problem of going to zero near threshold. Various remedies for this problem have been employed with varying degrees of success. We present a correction procedure formore » the Born cross-sections that employs the Elwert–Sommerfeld factor to correct for the use of plane waves instead of Coulomb waves in an attempt to produce a cross-section similar to that from using the more time consuming Coulomb Born approximation. We compare this new approximation with other, often employed correction procedures. Furthermore, we also look at some further modifications to our Born Elwert procedure and its combination with Y.K. Kim's correction of the Coulomb Born approximation for singly charged ions that more accurately approximate convergent close coupling calculations.« less

Description of waste pretreatment and interfacing systems dynamic simulation model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garbrick, D.J.; Zimmerman, B.D.

1995-05-01

The Waste Pretreatment and Interfacing Systems Dynamic Simulation Model was created to investigate the required pretreatment facility processing rates for both high level and low level waste so that the vitrification of tank waste can be completed according to the milestones defined in the Tri-Party Agreement (TPA). In order to achieve this objective, the processes upstream and downstream of the pretreatment facilities must also be included. The simulation model starts with retrieval of tank waste and ends with vitrification for both low level and high level wastes. This report describes the results of three simulation cases: one based on suggestedmore » average facility processing rates, one with facility rates determined so that approximately 6 new DSTs are required, and one with facility rates determined so that approximately no new DSTs are required. It appears, based on the simulation results, that reasonable facility processing rates can be selected so that no new DSTs are required by the TWRS program. However, this conclusion must be viewed with respect to the modeling assumptions, described in detail in the report. Also included in the report, in an appendix, are results of two sensitivity cases: one with glass plant water recycle steams recycled versus not recycled, and one employing the TPA SST retrieval schedule versus a more uniform SST retrieval schedule. Both recycling and retrieval schedule appear to have a significant impact on overall tank usage.« less

Buffing, burnishing, and stripping of vinyl asbestos floor tile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hollett, B.A.; Edwards, A.; Clark, P.J.

Studies were conducted to evaluate airborne asbestos concentrations during the three principal types of preventative maintenance (low-speed spray-buffing, ultra high-speed burnishing, and wet-stripping) used on asbestos-containing floor tiles. These were done under pre-existing and prepared levels of floor care maintenance. Airborne asbestos concentrations were measured before and during each floor care procedure to determine the magnitude of the increase in airborne asbestos levels during each procedure. Airborne total fiber concentrations were also measured for comparison with the Occupational Safety and Health Administration`s (OSHA) Permissible Exposure Limit (PEL) of 0.1 f/cm{sup 3}. Low-speed spray-buffing and wet-stripping were evaluated on pre-existing floormore » conditions and three levels of prepared floor care conditions (poor, medium, and good). Ultra high-speed burnishing and wet-stripping were evaluated on two levels of prepared floor care conditions (poor and good). Floor care conditions were defined in consultation with the Chemical Specialty Manufacturers Association and other representatives of floor-care chemical manufacturers. Controlled studies were conducted in an unoccupied building at the decommissioned Chanute Air Force Base in Rantoul, Illinois, with the cooperation of the U.S. Air Force. The building offered approximately 8600 ft{sup 2} of open floor space tiled with 9-inch by 9-inch resilient floor tile containing approximately 5% chrysotile asbestos.« less

Factors associated with contraceptive ideation among urban men in Nigeria.

PubMed

Babalola, Stella; Kusemiju, Bola; Calhoun, Lisa; Corroon, Meghan; Ajao, Bolanle

2015-08-01

To determine factors influencing the readiness of urban Nigerian men to adopt contraceptive methods. The data were derived from a cross-sectional household survey conducted in Ibadan and Kaduna between September and November 2012. The sample included 2358 men from both cities. An ideation framework was constructed and a multilevel analysis performed to identify factors associated with positive thinking about contraception. Correlates of ideation operated at the individual, household, and community levels. There is considerable cluster-level variability in ideation score. The key correlates included exposure to family planning promotion campaigns, education, age, religion, marital status, and community norms. Compared with no education, high education is associated with an approximately 6.7-point increase in ideation score (P<0.001). Men with a high level of NURHI program exposure had an average ideation score that was about 3.4 points higher than for their peers with no exposure (P<0.001). The ideation score for Muslims was lower by approximately 1.7 points, on average, than for Christians (P<0.001). A comprehensive strategy of communication and behavior change activities surrounding contraceptive use should be tailored to meet the needs of specific groups of men. Community-level interventions designed to mobilize community members and change social norms that hinder the spread of ideational characteristics that favor contraceptive use should be part of this comprehensive strategy. Copyright © 2015. Published by Elsevier Ireland Ltd.

The Suzaku View of Highly Ionized Outflows in AGN. 1; Statistical Detection and Global Absorber Properties

NASA Technical Reports Server (NTRS)

Gofford, Jason; Reeves, James N.; Tombesi, Francesco; Braito, Valentina; Turner, T. Jane; Miller, Lance; Cappi, Massimo

2013-01-01

We present the results of a new spectroscopic study of Fe K-band absorption in active galactic nuclei (AGN). Using data obtained from the Suzaku public archive we have performed a statistically driven blind search for Fe XXV Healpha and/or Fe XXVI Lyalpha absorption lines in a large sample of 51 Type 1.0-1.9 AGN. Through extensive Monte Carlo simulations we find that statistically significant absorption is detected at E greater than or approximately equal to 6.7 keV in 20/51 sources at the P(sub MC) greater than or equal tov 95 per cent level, which corresponds to approximately 40 per cent of the total sample. In all cases, individual absorption lines are detected independently and simultaneously amongst the two (or three) available X-ray imaging spectrometer detectors, which confirms the robustness of the line detections. The most frequently observed outflow phenomenology consists of two discrete absorption troughs corresponding to Fe XXV Healpha and Fe XXVI Lyalpha at a common velocity shift. From xstar fitting the mean column density and ionization parameter for the Fe K absorption components are log (N(sub H) per square centimeter)) is approximately equal to 23 and log (Xi/erg centimeter per second) is approximately equal to 4.5, respectively. Measured outflow velocities span a continuous range from less than1500 kilometers per second up to approximately100 000 kilometers per second, with mean and median values of approximately 0.1 c and approximately 0.056 c, respectively. The results of this work are consistent with those recently obtained using XMM-Newton and independently provides strong evidence for the existence of very highly ionized circumnuclear material in a significant fraction of both radio-quiet and radio-loud AGN in the local universe.

Deflection amplifier for image dissectors

NASA Technical Reports Server (NTRS)

Salomon, P. M.

1977-01-01

Balanced symmetrical y-axis amplifier uses zener-diode level shifting to interface operational amplifiers to high voltage bipolar output stages. Nominal voltage transfer characteristic is 40 differential output volts per input volt; bandwidth, between -3-dB points, is approximately 8 kHz; loop gain is nominally 89 dB with closed loop gain of 26 dB.

The Use of Teachers' Baseline Normative Beliefs to Guide Professional Development in Teaching Mathematics

ERIC Educational Resources Information Center

Lloyd, Mary Elizabeth Riley; Veal, William; Howell, Malia

2016-01-01

This article describes the normative beliefs and the discursive claims related to mathematics and teaching mathematics made by approximately 50 middle-level and secondary mathematics teachers within four high-need local education associations participating in a Mathematics and Science Partnership with a southeastern college's Science and Math for…

Fatal overdose from Bendectin.

PubMed

Bayley, M; Walsh, F M; Valaske, M J

1975-05-01

A three-year old male ingested approximately 100 tablets of Bendectin. He developed tonic-clonic seizures followed by cardiac arrest. Toxicologic analysis yielded high levels of doxylamine, dicyclomine, and pyridoxine in blood, peritoneal fluid, and tissue homogenates. The antihistamine, doxylamine succinate appears to be the toxic constituent. Analytical methods used to document the case are herein described.

Generalized Anxiety Symptoms and Identity Processes in Cross-Cultural Samples of Adolescents from the General Population

ERIC Educational Resources Information Center

Crocetti, Elisabetta; Hale, William W., III.; Dimitrova, Radosveta; Abubakar, Amina; Gao, Cheng-Hai; Agaloos Pesigan, Ivan Jacob

2015-01-01

Background: Approximately 20% of adolescents around the world experience mental health problems, most commonly depression or anxiety. High levels of anxiety disorder symptoms can hinder adolescent development, persist into adulthood, and predict negative mental outcomes, such as suicidal ideation and attempts. Objectives: We analyzed generalized…

Understanding quantum phenomena without solving the Schrödinger equation: the case of the finite square well

NASA Astrophysics Data System (ADS)

Barsan, Victor

2015-11-01

An approximate formula for the energy levels of the bound states of a particle in a finite square well are obtained, without using the Schrödinger equation. The physics and mathematics involved in this approach are accessible to a gifted high school student.

Invasion and transmission of Salmonella Kentucky in an adult dairy herd using approximate Bayesian computation

USDA-ARS?s Scientific Manuscript database

An outbreak of Salmonella Kentucky followed by a high level of sustained endemic prevalence was recently observed in a US adult dairy herd enrolled in a longitudinal study involving intensive fecal sampling. To understand the invasion ability and transmission dynamics of Salmonella Kentucky in dairy...

Pleistocene refugia and polytopic replacement of diploids by tetraploids in the Patagonian and Subantarctic plant Hypochaeris incana (Asteraceae, Cichorieae).

PubMed

Tremetsberger, Karin; Urtubey, Estrella; Terrab, Anass; Baeza, Carlos M; Ortiz, María Angeles; Talavera, María; König, Christiane; Temsch, Eva M; Kohl, Gudrun; Talavera, Salvador; Stuessy, Tod F

2009-09-01

We report the phylogeographic pattern of the Patagonian and Subantarctic plant Hypochaeris incana endemic to southeastern South America. We applied amplified fragment length polymorphism (AFLP) and chloroplast DNA (cpDNA) analysis to 28 and 32 populations, respectively, throughout its distributional range and assessed ploidy levels using flow cytometry. While cpDNA data suggest repeated or simultaneous parallel colonization of Patagonia and Tierra del Fuego by several haplotypes and/or hybridization, AFLPs reveal three clusters corresponding to geographic regions. The central and northern Patagonian clusters (approximately 38-51 degrees S), which are closer to the outgroup, contain mainly tetraploid, isolated and highly differentiated populations with low genetic diversity. To the contrary, the southern Patagonian and Fuegian cluster (approximately 51-55 degrees S) contains mainly diploid populations with high genetic diversity and connected by high levels of gene flow. The data suggest that H. incana originated at the diploid level in central or northern Patagonia, from where it migrated south. All three areas, northern, central and southern, have similar levels of rare and private AFLP bands, suggesting that all three served as refugia for H. incana during glacial times. In southern Patagonia and Tierra del Fuego, the species seems to have expanded its populational system in postglacial times, when the climate became warmer and more humid. In central and northern Patagonia, the populations seem to have become restricted to favourable sites with increasing temperature and decreasing moisture and there was a parallel replacement of diploids by tetraploids in local populations.

Urea-N recycling in lactating dairy cows fed diets with 2 different levels of dietary crude protein and starch with or without monensin.

PubMed

Recktenwald, E B; Ross, D A; Fessenden, S W; Wall, C J; Van Amburgh, M E

2014-03-01

Rumensin (monensin; Elanco Animal Health, Greenfield, IN) has been shown to reduce ammonia production and microbial populations in vitro; thus, it would be assumed to reduce ruminal ammonia production and subsequent urea production and consequently affect urea recycling. The objective of this experiment was to determine the effects of 2 levels of dietary crude protein (CP) and 2 levels of starch, with and without Rumensin on urea-N recycling in lactating dairy cattle. Twelve lactating Holstein dairy cows (107 ± 21 d in milk, 647 kg ± 37 kg of body weight) were fed diets characterized as having high (16.7%) or low (15.3%) CP with or without Rumensin, while dietary starch levels (23 vs. 29%) were varied between 2 feeding periods with at least 7d of adaptation between measurements. Cows assigned to high or low protein and to Rumensin or no Rumensin remained on those treatments to avoid carryover effects. The diets consisted of approximately 40% corn silage, 20% alfalfa hay, and 40% concentrate mix specific to the treatment diets, with 0.5 kg of wheat straw added to the high starch diets to enhance effective fiber intake. The diets were formulated using Cornell Net Carbohydrate and Protein System (version 6.1), and the low-protein diets were formulated to be deficient for rumen ammonia to create conditions that should enhance the demand for urea recycling. The high-protein diets were formulated to be positive for both rumen ammonia and metabolizable protein. Rumen fluid, urine, feces, and milk samples were collected before and after a 72-h continuous jugular infusion of (15)N(15)N-urea. Total urine and feces were collected during the urea infusions for N balance measurements. Milk yield and dry matter intake were improved in cows fed the higher level of dietary CP and by Rumensin. Ruminal ammonia and milk and plasma urea nitrogen concentrations corresponded to dietary CP concentration. As has been shown in vitro, Rumensin reduced rumen ammonia concentration by approximately 23% but did not affect urea entry rate or gastrointestinal entry rate. Urea entry rate averaged approximately 57% of total N intake for cattle with and without Rumensin, and gastrointestinal rate was similar at 43 and 42% of N intake for cattle fed and not fed Rumensin, respectively. The cattle fed the high-protein diet had a 25% increase in urea entry rate and no effect of starch level was observed for any recycling parameters. Contrary to our hypothesis, Rumensin did not alter urea production and recycling. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Test particle propagation in magnetostatic turbulence. 2: The local approximation method

NASA Technical Reports Server (NTRS)

Klimas, A. J.; Sandri, G.; Scudder, J. D.; Howell, D. R.

1976-01-01

An approximation method for statistical mechanics is presented and applied to a class of problems which contains a test particle propagation problem. All of the available basic equations used in statistical mechanics are cast in the form of a single equation which is integrodifferential in time and which is then used as the starting point for the construction of the local approximation method. Simplification of the integrodifferential equation is achieved through approximation to the Laplace transform of its kernel. The approximation is valid near the origin in the Laplace space and is based on the assumption of small Laplace variable. No other small parameter is necessary for the construction of this approximation method. The n'th level of approximation is constructed formally, and the first five levels of approximation are calculated explicitly. It is shown that each level of approximation is governed by an inhomogeneous partial differential equation in time with time independent operator coefficients. The order in time of these partial differential equations is found to increase as n does. At n = 0 the most local first order partial differential equation which governs the Markovian limit is regained.

Big Stimulus, Little Ears: Safety in Administering Vestibular Evoked Myogenic Potentials (VEMP) in Children

PubMed Central

Thomas, Megan L.A.; Fitzpatrick, Denis; McCreery, Ryan; Janky, Kristen L.

2017-01-01

Background Cervical and ocular Vestibular Evoked Myogenic Potentials (VEMPs) have become common clinical vestibular assessments. However, VEMP testing requires high intensity stimuli, raising concerns regarding safety with children, where sound pressure levels may be higher due to their smaller ear canal volumes. Purpose The purpose of this study was to estimate the range of peak-to-peak equivalent sound pressure levels (peSPLs) in child and adult ears in response to high intensity stimuli (i.e., 100 dB normal hearing level (nHL)) commonly used for VEMP testing and make a determination of whether acoustic stimuli levels with VEMP testing are safe for use in children. Research Design Prospective Experimental. Study Sample Ten children (4–6 years) and ten young adults (24 – 35 years) with normal hearing sensitivity and middle ear function participated in the study. Data Collection and Analysis Probe microphone peSPL measurements of clicks and 500 Hz tonebursts (TBs) were recorded in tubes of small, medium, and large diameter, and in a Brüel & Kjær Ear Simulator Type 4157 to assess for linearity of the stimulus at high levels. The different diameter tubes were used to approximate the range of cross-sectional areas in infant, child, and adult ears, respectively. Equivalent ear canal volume and peSPL measurements were then recorded in child and adult ears. Lower intensity levels were used in the participant’s ears to limit exposure to high intensity sound. The peSPL measurements in participant ears were extrapolated using predictions from linear mixed models to determine if equivalent ear canal volume significantly contributed to overall peSPL and to estimate the mean and 95% confidence intervals of peSPLs in child and adult ears when high intensity stimulus levels (100 dB nHL) are used for VEMP testing without exposing subjects to high-intensity stimuli. Results Measurements from the coupler and tubes suggested: 1) each stimuli was linear, 2) there were no distortions or non-linearities at high levels, and 3) peSPL increased with decreased tube diameter. Measurements in participant ears suggested: 1) peSPL was approximately 3 dB larger in child compared to adult ears, and 2) peSPL was larger in response to clicks compared to 500 Hz TBs. The model predicted the following 95% confidence interval for a 100 dB nHL click: 127–136.5 dB peSPL in adult ears and 128.7–138.2 dB peSPL in child ears. The model predicted the following 95% confidence interval for a 100 dB nHL 500 Hz TB stimulus: 122.2 – 128.2 dB peSPL in adult ears and 124.8–130.8 dB peSPL in child ears. Conclusions Our findings suggest that 1) when completing VEMP testing, the stimulus is approximately 3 dB higher in a child’s ear, 2) a 500 Hz TB is recommended over a click as it has lower peSPL compared to the click, and 3) both duration and intensity should be considered when choosing VEMP stimuli. Calculating the total sound energy exposure for your chosen stimuli is recommended as it accounts for both duration and intensity. When using this calculation for children, consider adding 3 dB to the stimulus level. PMID:28534730

Big Stimulus, Little Ears: Safety in Administering Vestibular-Evoked Myogenic Potentials in Children.

PubMed

Thomas, Megan L A; Fitzpatrick, Denis; McCreery, Ryan; Janky, Kristen L

2017-05-01

Cervical and ocular vestibular-evoked myogenic potentials (VEMPs) have become common clinical vestibular assessments. However, VEMP testing requires high intensity stimuli, raising concerns regarding safety with children, where sound pressure levels may be higher due to their smaller ear canal volumes. The purpose of this study was to estimate the range of peak-to-peak equivalent sound pressure levels (peSPLs) in child and adult ears in response to high intensity stimuli (i.e., 100 dB normal hearing level [nHL]) commonly used for VEMP testing and make a determination of whether acoustic stimuli levels with VEMP testing are safe for use in children. Prospective experimental. Ten children (4-6 years) and ten young adults (24-35 years) with normal hearing sensitivity and middle ear function participated in the study. Probe microphone peSPL measurements of clicks and 500 Hz tonebursts (TBs) were recorded in tubes of small, medium, and large diameter, and in a Brüel & Kjær Ear Simulator Type 4157 to assess for linearity of the stimulus at high levels. The different diameter tubes were used to approximate the range of cross-sectional areas in infant, child, and adult ears, respectively. Equivalent ear canal volume and peSPL measurements were then recorded in child and adult ears. Lower intensity levels were used in the participant's ears to limit exposure to high intensity sound. The peSPL measurements in participant ears were extrapolated using predictions from linear mixed models to determine if equivalent ear canal volume significantly contributed to overall peSPL and to estimate the mean and 95% confidence intervals of peSPLs in child and adult ears when high intensity stimulus levels (100 dB nHL) are used for VEMP testing without exposing subjects to high-intensity stimuli. Measurements from the coupler and tubes suggested: 1) each stimuli was linear, 2) there were no distortions or nonlinearities at high levels, and 3) peSPL increased with decreased tube diameter. Measurements in participant ears suggested: 1) peSPL was approximately 3 dB larger in child compared to adult ears, and 2) peSPL was larger in response to clicks compared to 500 Hz TBs. The model predicted the following 95% confidence interval for a 100 dB nHL click: 127-136.5 dB peSPL in adult ears and 128.7-138.2 dB peSPL in child ears. The model predicted the following 95% confidence interval for a 100 dB nHL 500 Hz TB stimulus: 122.2-128.2 dB peSPL in adult ears and 124.8-130.8 dB peSPL in child ears. Our findings suggest that 1) when completing VEMP testing, the stimulus is approximately 3 dB higher in a child's ear, 2) a 500 Hz TB is recommended over a click as it has lower peSPL compared to the click, and 3) both duration and intensity should be considered when choosing VEMP stimuli. Calculating the total sound energy exposure for your chosen stimuli is recommended as it accounts for both duration and intensity. When using this calculation for children, consider adding 3 dB to the stimulus level. American Academy of Audiology

Application of LIBS to the in-line process control of liquid high-alloy steel under pressure.

PubMed

Hubmer, Gerhard; Kitzberger, Reinhard; Mörwald, Karl

2006-05-01

A process optimization and control system called VAI-CON Chem has been developed that uses laser-induced breakdown spectroscopy (LIBS) to quasi-continuously chemically analyze liquid high-alloy steel under pressure. The beam from a Nd:YAG laser, located on safe ground and operating at its fundamental wavelength, is guided by a mirror system to a process tuyere below bath level. Passing through the approximately 1.5 m long tuyere, the beam is then focused onto the steel bath. Light emitted from the induced plasma passes back through the tuyere, which is coupled to a fiber optic cable that carries the information over a distance of approximately 10 m back to an Echelle spectrometer located beside the laser. Calibrations were performed using the complete system, located in a laboratory, during system testing. An induction furnace was used to simulate the AOD converter, wherein the samples were molten and superheated to a temperature of approximately 1600 degrees C and kept at a pressure of approximately 1.7 bar under an argon atmosphere. Twelve different high alloyed reference samples taken from normal AOD production with Fe concentrations of >48 wt.% and non-Fe element concentrations of up to 25 wt.% were available for calibration. The mean residual deviations (defined as the square root of the variance of the concentration ratios determined by LIBS and the reference element concentration ratios) obtained were close to those reported for other comparable high-alloy samples that were investigated at room temperature under normal atmospheric pressure.

Construction of nested maximin designs based on successive local enumeration and modified novel global harmony search algorithm

NASA Astrophysics Data System (ADS)

Yi, Jin; Li, Xinyu; Xiao, Mi; Xu, Junnan; Zhang, Lin

2017-01-01

Engineering design often involves different types of simulation, which results in expensive computational costs. Variable fidelity approximation-based design optimization approaches can realize effective simulation and efficiency optimization of the design space using approximation models with different levels of fidelity and have been widely used in different fields. As the foundations of variable fidelity approximation models, the selection of sample points of variable-fidelity approximation, called nested designs, is essential. In this article a novel nested maximin Latin hypercube design is constructed based on successive local enumeration and a modified novel global harmony search algorithm. In the proposed nested designs, successive local enumeration is employed to select sample points for a low-fidelity model, whereas the modified novel global harmony search algorithm is employed to select sample points for a high-fidelity model. A comparative study with multiple criteria and an engineering application are employed to verify the efficiency of the proposed nested designs approach.

Importance of 'blue' photon levels for lettuce seedlings grown under red-light-emitting diodes

NASA Technical Reports Server (NTRS)

Hoenecke, M. E.; Bula, R. J.; Tibbitts, T. W.

1992-01-01

Light-emitting diodes (LEDs) with high-intensity output are being studied as a photosynthetic light source for plants. High-output LEDs have peak emission at approximately 660 nm concentrated in a waveband of +/- 30 nm. Lettuce (Lactuca sativa Grand Rapids') seedlings developed extended hypocotyls and elongated cotyledons when grown under these LEDs as a sole source of irradiance. This extension and elongation was prevented when the red LED radiation was supplemented with more than 15 micromoles m-2 s-1 of 400- to 500-nm photons from blue fluorescent lamps. Blue radiation effects were independent of the photon level of the red radiation.

Extruder system for high-throughput/steady-state hydrogen ice supply and application for pellet fueling of reactor-scale fusion experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Combs, S.K.; Foust, C.R.; Qualls, A.L.

Pellet injection systems for the next-generation fusion devices, such as the proposed International Thermonuclear Experimental Reactor (ITER), will require feed systems capable of providing a continuous supply of hydrogen ice at high throughputs. A straightforward concept in which multiple extruder units operate in tandem has been under development at the Oak Ridge National Laboratory. A prototype with three large-volume extruder units has been fabricated and tested in the laboratory. In experiments, it was found that each extruder could provide volumetric ice flow rates of up to {approximately}1.3 cm{sup 3}/s (for {approximately}10 s), which is sufficient for fueling fusion reactors atmore » the gigawatt power level. With the three extruders of the prototype operating in sequence, a steady rate of {approximately}0.33 cm{sup 3}/s was maintained for a duration of 1 h. Even steady-state rates approaching the full ITER design value ({approximately}1 cm{sup 3}/s) may be feasible with the prototype. However, additional extruder units (1{endash}3) would facilitate operations at the higher throughputs and reduce the duty cycle of each unit. The prototype can easily accommodate steady-state pellet fueling of present large tokamaks or other near-term plasma experiments.« less

The effect of pH and chloride concentration on the stability and antimicrobial activity of chlorine-based sanitizers.

PubMed

Waters, Brian W; Hung, Yen-Con

2014-04-01

Chlorinated water and electrolyzed oxidizing (EO) water solutions were made to compare the free chlorine stability and microbicidal efficacy of chlorine-containing solutions with different properties. Reduction of Escherichia coli O157:H7 was greatest in fresh samples (approximately 9.0 log CFU/mL reduction). Chlorine loss in "aged" samples (samples left in open bottles) was greatest (approximately 40 mg/L free chlorine loss in 24 h) in low pH (approximately 2.5) and high chloride (Cl(-) ) concentrations (greater than 150 mg/L). Reduction of E. coli O157:H7 was also negatively impacted (<1.0 log CFU/mL reduction) in aged samples with a low pH and high Cl(-) . Higher pH values (approximately 6.0) did not appear to have a significant effect on free chlorine loss or numbers of surviving microbial cells when fresh and aged samples were compared. This study found chloride levels in the chlorinated and EO water solutions had a reduced effect on both free chlorine stability and its microbicidal efficacy in the low pH solutions. Greater concentrations of chloride in pH 2.5 samples resulted in decreased free chlorine stability and lower microbicidal efficacy. © 2014 Institute of Food Technologists®

Fast oscillations in cortical-striatal networks switch frequency following rewarding events and stimulant drugs.

PubMed

Berke, J D

2009-09-01

Oscillations may organize communication between components of large-scale brain networks. Although gamma-band oscillations have been repeatedly observed in cortical-basal ganglia circuits, their functional roles are not yet clear. Here I show that, in behaving rats, distinct frequencies of ventral striatal local field potential oscillations show coherence with different cortical inputs. The approximately 50 Hz gamma oscillations that normally predominate in awake ventral striatum are coherent with piriform cortex, whereas approximately 80-100 Hz high-gamma oscillations are coherent with frontal cortex. Within striatum, entrainment to gamma rhythms is selective to fast-spiking interneurons, with distinct fast-spiking interneuron populations entrained to different gamma frequencies. Administration of the psychomotor stimulant amphetamine or the dopamine agonist apomorphine causes a prolonged decrease in approximately 50 Hz power and increase in approximately 80-100 Hz power. The same frequency switch is observed for shorter epochs spontaneously in awake, undrugged animals and is consistently provoked for < 1 s following reward receipt. Individual striatal neurons can participate in these brief high-gamma bursts with, or without, substantial changes in firing rate. Switching between discrete oscillatory states may allow different modes of information processing during decision-making and reinforcement-based learning, and may also be an important systems-level process by which stimulant drugs affect cognition and behavior.

A broadband fast multipole accelerated boundary element method for the three dimensional Helmholtz equation.

PubMed

Gumerov, Nail A; Duraiswami, Ramani

2009-01-01

The development of a fast multipole method (FMM) accelerated iterative solution of the boundary element method (BEM) for the Helmholtz equations in three dimensions is described. The FMM for the Helmholtz equation is significantly different for problems with low and high kD (where k is the wavenumber and D the domain size), and for large problems the method must be switched between levels of the hierarchy. The BEM requires several approximate computations (numerical quadrature, approximations of the boundary shapes using elements), and these errors must be balanced against approximations introduced by the FMM and the convergence criterion for iterative solution. These different errors must all be chosen in a way that, on the one hand, excess work is not done and, on the other, that the error achieved by the overall computation is acceptable. Details of translation operators for low and high kD, choice of representations, and BEM quadrature schemes, all consistent with these approximations, are described. A novel preconditioner using a low accuracy FMM accelerated solver as a right preconditioner is also described. Results of the developed solvers for large boundary value problems with 0.0001 less, similarkD less, similar500 are presented and shown to perform close to theoretical expectations.

[Effects of sediment on the early settlement stage of Sargassum horneri on rocky subtidal reefs].

PubMed

Bi, Yuan-Xin; Zhang, Shou-Yu; Wu, Zu-Li

2013-05-01

By using sediment trap and suction pump to measure the relative sediment levels across different sites and water depths, and through the in situ measurements of Sargassum horneri density, this paper assessed the relationships between the distribution of S. horneri and the sediment levels and wave exposure on the rocky subtidal platforms around Gouqi Island, China. The laboratory-based experiments were also conducted to test the effects of different sediment levels on the attachment of S. horneri zygote and the survival rate of S. horneri germling after the attachment. S. horneri predominated at the sites with lesser sediment and wave exposure, but less distributed in the sites with high level sediment and wave-exposure. At different water depths, the distribution of S. horneri was negatively correlated with the amount of sediment. A medium dusting (dry mass 10.47 mg x cm(-2), approximate 0.543 mm deep) of sediment on the plate reduced the percentage of S. horneri zygotes attached to the substratum by 4.4%, and a heavy dusting (dry mass 13.96 mg x cm(-2), approximate 0.724 mm deep) of sediment on the plate completely prevented the attachment. One week after the settlement of the zygotes, there were 24% of the germlings still survived when the dry mass sediment coverage was 13.96 mg x cm(-2). However, when the dry mass sediment coverage was up to 34.9 mg x cm(-2) (approximate 1.81 mm deep), 100% of the germlings died. Overall, the distribution of S. horneri was not only related to sediment level, but also restricted by wave exposure to some extent. Sediment level was a critical factor affecting the distribution of S. horneri, particularly at its zygote attachment stage.

Power Series Approximation for the Correlation Kernel Leading to Kohn-Sham Methods Combining Accuracy, Computational Efficiency, and General Applicability

NASA Astrophysics Data System (ADS)

Erhard, Jannis; Bleiziffer, Patrick; Görling, Andreas

2016-09-01

A power series approximation for the correlation kernel of time-dependent density-functional theory is presented. Using this approximation in the adiabatic-connection fluctuation-dissipation (ACFD) theorem leads to a new family of Kohn-Sham methods. The new methods yield reaction energies and barriers of unprecedented accuracy and enable a treatment of static (strong) correlation with an accuracy of high-level multireference configuration interaction methods but are single-reference methods allowing for a black-box-like handling of static correlation. The new methods exhibit a better scaling of the computational effort with the system size than rivaling wave-function-based electronic structure methods. Moreover, the new methods do not suffer from the problem of singularities in response functions plaguing previous ACFD methods and therefore are applicable to any type of electronic system.

Atmospheric electromagnetic pulse propagation effects from thick targets in a terawatt laser target chamber.

PubMed

Remo, John L; Adams, Richard G; Jones, Michael C

2007-08-20

Generation and effects of atmospherically propagated electromagnetic pulses (EMPs) initiated by photoelectrons ejected by the high density and temperature target surface plasmas from multiterawatt laser pulses are analyzed. These laser radiation pulse interactions can significantly increase noise levels, thereby obscuring data (sometimes totally) and may even damage sensitive probe and detection instrumentation. Noise effects from high energy density (approximately multiterawatt) laser pulses (approximately 300-400 ps pulse widths) interacting with thick approximately 1 mm) metallic and dielectric solid targets and dielectric-metallic powder mixtures are interpreted as transient resonance radiation associated with surface charge fluctuations on the target chamber that functions as a radiating antenna. Effective solutions that minimize atmospheric EMP effects on internal and proximate electronic and electro-optical equipment external to the system based on systematic measurements using Moebius loop antennas, interpretations of signal periodicities, and dissipation indicators determining transient noise origin characteristics from target emissions are described. Analytic models for the effect of target chamber resonances and associated noise current and temperature in a probe diode laser are described.

Extended computational kernels in a massively parallel implementation of the Trotter-Suzuki approximation

NASA Astrophysics Data System (ADS)

Wittek, Peter; Calderaro, Luca

2015-12-01

We extended a parallel and distributed implementation of the Trotter-Suzuki algorithm for simulating quantum systems to study a wider range of physical problems and to make the library easier to use. The new release allows periodic boundary conditions, many-body simulations of non-interacting particles, arbitrary stationary potential functions, and imaginary time evolution to approximate the ground state energy. The new release is more resilient to the computational environment: a wider range of compiler chains and more platforms are supported. To ease development, we provide a more extensive command-line interface, an application programming interface, and wrappers from high-level languages.

SSME structural dynamic model development

NASA Technical Reports Server (NTRS)

Foley, Michael J.

1989-01-01

The high pressure fuel turbopump (HPFTP) is a major component of the Space Shuttle Main Engine (SSME) powerhead. The device is a three stage centrifugal pump that is directly driven by a two stage hot gas turbine. The purpose of the pump is to deliver fuel (liquid hydrogen) from the low pressure fuel turbopump (LPFTP) through the main fuel valve (MFV) to the thrust chamber coolant circuits. In doing so, the pump pressurizes the fuel from an inlet pressure of approximately 178 psi to a discharge pressure of over 6000 psi. At full power level (FPL), the pump rotates at a speed of over 37,000 rpm while generating approximately 77,000 horsepower. Obviously, a pump failure at these speeds and power levels could jeopardize the mission. Results are summarized for work in which the solutions obtained from analytical models of the fuel turbopump impellers are compared with the results obtained from dynamic tests.

Numerical Schemes for the Hamilton-Jacobi and Level Set Equations on Triangulated Domains

NASA Technical Reports Server (NTRS)

Barth, Timothy J.; Sethian, James A.

1997-01-01

Borrowing from techniques developed for conservation law equations, numerical schemes which discretize the Hamilton-Jacobi (H-J), level set, and Eikonal equations on triangulated domains are presented. The first scheme is a provably monotone discretization for certain forms of the H-J equations. Unfortunately, the basic scheme lacks proper Lipschitz continuity of the numerical Hamiltonian. By employing a virtual edge flipping technique, Lipschitz continuity of the numerical flux is restored on acute triangulations. Next, schemes are introduced and developed based on the weaker concept of positive coefficient approximations for homogeneous Hamiltonians. These schemes possess a discrete maximum principle on arbitrary triangulations and naturally exhibit proper Lipschitz continuity of the numerical Hamiltonian. Finally, a class of Petrov-Galerkin approximations are considered. These schemes are stabilized via a least-squares bilinear form. The Petrov-Galerkin schemes do not possess a discrete maximum principle but generalize to high order accuracy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daud, A.I.; Bumpus, F.M.; Husain, A.

Ovarian angiotensin I (Ang I)-converting enzyme (ACE), estimated by the specific binding of the ACE inhibitor (125I)iodo-MK-351A, is localized on multiple ovarian structures, including follicular granulosa cells, corpora lutea, terminal epithelium, and ovarian blood vessels, but total ovarian ACE does not display a cyclic pattern of variation during the rat estrous cycle. We have previously shown that ACE is localized on the granulosa cell layer of a subpopulation of rat ovarian follicles. Our present study shows that ovarian granulosa cells contain high affinity (binding site affinity (Kd), approximately 90 pM) and low capacity (binding site density (Bmax), approximately 12 fmol/2.5more » X 10(5) cells) (125I)iodo-MK-351A-binding sites and convert (125I)iodo-Ang I to (125I)iodo-Ang II (greater than 85% of this conversion was inhibited by the ACE inhibitor captopril). Throughout the rat estrous cycle, 94-100% of developing follicles and 89-96% of atretic follicles contained high levels of ACE; however, ACE was either not observed or its levels were very low in preovulatory follicles. These findings indicate the presence of high levels of biologically active ACE on the surface of granulosa cells and suggest a potential role for follicular ACE in early stages of follicular maturation and atresia. Although ACE is known to process a variety of peptides found within the ovary, and these peptides may have opposing effects on follicular maturation, we attempted to define the cumulative effect of ACE inhibition on follicular maturation.« less

Production of Ginkgo leaf-shaped basidiocarps of the Lingzhi or Reishi medicinal mushroom Ganoderma lucidum (higher Basidiomycetes), containing high levels of α- and β-D-glucan and ganoderic acid A.

PubMed

Yajima, Yuka; Miyazaki, Minoru; Okita, Noriyasu; Hoshino, Tamotsu

2013-01-01

Ganoderic acid A and α- and β-D-glucan content were compared among morphologically different basidiocarps of the medicinal mushroom Ganoderma lucidum. Ginkgo leaf-shaped basidiocarps gradually hardened from the base to the pileus and accumulated a higher amount of bioactive components than normal (kidney-shaped) and antler/deer horn-shaped basidiocarps. In the normal G. lucidum stipe, the outer context contained the highest amount of α- and β-D-glucan (approximately 55%) and the highest amount of ganoderic acid A (approximately 0.3%). Ginkgo leaf-shaped G. lucidum had a large area of outer layer and stout outer context, which contributed to their high α- and β-D-glucan and ganoderic acid A content.

A method for predicting DCT-based denoising efficiency for grayscale images corrupted by AWGN and additive spatially correlated noise

NASA Astrophysics Data System (ADS)

Rubel, Aleksey S.; Lukin, Vladimir V.; Egiazarian, Karen O.

2015-03-01

Results of denoising based on discrete cosine transform for a wide class of images corrupted by additive noise are obtained. Three types of noise are analyzed: additive white Gaussian noise and additive spatially correlated Gaussian noise with middle and high correlation levels. TID2013 image database and some additional images are taken as test images. Conventional DCT filter and BM3D are used as denoising techniques. Denoising efficiency is described by PSNR and PSNR-HVS-M metrics. Within hard-thresholding denoising mechanism, DCT-spectrum coefficient statistics are used to characterize images and, subsequently, denoising efficiency for them. Results of denoising efficiency are fitted for such statistics and efficient approximations are obtained. It is shown that the obtained approximations provide high accuracy of prediction of denoising efficiency.

Evaluation of high-level clouds in cloud resolving model simulations with ARM and KWAJEX observations

DOE PAGES

Liu, Zheng; Muhlbauer, Andreas; Ackerman, Thomas

2015-11-05

In this paper, we evaluate high-level clouds in a cloud resolving model during two convective cases, ARM9707 and KWAJEX. The simulated joint histograms of cloud occurrence and radar reflectivity compare well with cloud radar and satellite observations when using a two-moment microphysics scheme. However, simulations performed with a single moment microphysical scheme exhibit low biases of approximately 20 dB. During convective events, two-moment microphysical overestimate the amount of high-level cloud and one-moment microphysics precipitate too readily and underestimate the amount and height of high-level cloud. For ARM9707, persistent large positive biases in high-level cloud are found, which are not sensitivemore » to changes in ice particle fall velocity and ice nuclei number concentration in the two-moment microphysics. These biases are caused by biases in large-scale forcing and maintained by the periodic lateral boundary conditions. The combined effects include significant biases in high-level cloud amount, radiation, and high sensitivity of cloud amount to nudging time scale in both convective cases. The high sensitivity of high-level cloud amount to the thermodynamic nudging time scale suggests that thermodynamic nudging can be a powerful ‘‘tuning’’ parameter for the simulated cloud and radiation but should be applied with caution. The role of the periodic lateral boundary conditions in reinforcing the biases in cloud and radiation suggests that reducing the uncertainty in the large-scale forcing in high levels is important for similar convective cases and has far reaching implications for simulating high-level clouds in super-parameterized global climate models such as the multiscale modeling framework.« less

Protection of the public in situations of prolonged radiation exposure. The application of the Commission's system of radiological protection to controllable radiation exposure due to natural sources and long-lived radioactive residues.

PubMed

1999-01-01

This report provides guidance on the application of the ICRP system of radiological protection to prolonged exposure situations affecting members of the public. It addresses the general application of the Commission's system to the control of prolonged exposures resulting from practices and to the undertaking of interventions in prolonged exposure situations. Additionally, it provides recommendations on generic reference levels for such interventions. The report also considers some specific situations and discusses a number of issues that have been of concern, namely: natural radiation sources that may give rise to high doses; the restoration and rehabilitation of sites where human activities involving radioactive substances have been carried out; the return to 'normality' following an accident that has released radioactive substances to the environment; and the global marketing of commodities for public consumption that contain radioactive substances. Annexes provide some examples of prolonged exposure situations and discuss the radiological protection quantities, radiation-induced health effects and aspects of the Commission's system of radiological protection relevant to prolonged exposure. Quantitative recommendations for prolonged exposures are provided in the report. They must be interpreted with extreme caution; Chapters 4 and 5 stress the upper bound nature of the following values: Generic reference levels for intervention, in terms of existing total annual doses, are given as < approximately 100 mSv, above which intervention is almost always justifiable (situations for which the annual dose threshold for deterministic effects in relevant organs is exceeded will almost always require intervention), and < approximately 10 mSv, below which intervention is not likely to be justifiable (and above which it may be necessary). Intervention exemption levels for commodities, especially building materials, are expressed as an additional annual dose of approximately 1 mSv. The dose limit for exposures of the public from practices is expressed as aggregated (prolonged and transitory) additional annual doses from all relevant practices of 1 mSv. Dose constraints for sources within practices are expressed as an additional annual dose lower than 1 mSv (e.g. of approximately 0.3 mSv), which could be approximately 0.1 mSv for the prolonged exposure component. An exemption level for practices is expressed as an additional annual dose of approximately 0.01 mSv.

Multigrid Techniques for Highly Indefinite Equations

NASA Technical Reports Server (NTRS)

Shapira, Yair

1996-01-01

A multigrid method for the solution of finite difference approximations of elliptic PDE's is introduced. A parallelizable version of it, suitable for two and multi level analysis, is also defined, and serves as a theoretical tool for deriving a suitable implementation for the main version. For indefinite Helmholtz equations, this analysis provides a suitable mesh size for the coarsest grid used. Numerical experiments show that the method is applicable to diffusion equations with discontinuous coefficients and highly indefinite Helmholtz equations.

Challenge of the Future: Visions and Versions.

ERIC Educational Resources Information Center

Conboy, William A., Ed.

This book presents background information and approximately 40 articles on various aspects of the future. It is intended for use as a textbook and/or reader in advanced high school or college level future studies courses. The objectives are to help students of the future examine major problems and issues and to encourage them to devise new models…

The Teaching of Modern Languages to Migrant Workers. (Turkey), 1973.

ERIC Educational Resources Information Center

Council of Europe, Strasbourg (France). Documentation Center for Education in Europe.

The number of migrant workers Turkey has sent to foreign countries has now reached approximately 1 million. Educational level of these workers is: 67 percent - primary school education; 24 percent - secondary school education; and 9 percent - high school education. However, 98 percent of these workers do not know the language of the country to…

Functional Communication Training to Increase Communication Skills for Young Children with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Collins, Terri Lane Sutherland

2010-01-01

The prevalence rates of children being diagnosed with autism spectrum disorder (ASD) continue to rise at alarming rates. Recent figures suggest that approximately 1 in 90 children have an ASD. Children with ASD have significant deficits that affect communication skills and social interaction. Children with ASD may also engage in high levels of…

Perceptions of Father Involvement Patterns in Teenage-Mother Families: Predictors and Links to Mothers' Psychological Adjustment

ERIC Educational Resources Information Center

Kalil, Ariel; Ziol-Guest, Kathleen M.; Coley, Rebekah Levine

2005-01-01

Based on adolescent mothers' reports, longitudinal patterns of involvement of young, unmarried biological fathers (n=77) in teenage-mother families using cluster analytic techniques were examined. Approximately one third of fathers maintained high levels of involvement over time, another third demonstrated low involvement at both time points, and…

Three-dimensional numerical simulation of the 20 June 1991, Orlando microburst

NASA Technical Reports Server (NTRS)

Proctor, Fred H.

1992-01-01

On 20 June 1991, NASA's Boeing 737, equipped with in-situ and look-ahead wind-shear detection systems, made direct low-level penetrations (300-350 m AGL) through a microburst during several stages of its evolution. This microburst was located roughly 20 km northeast of Orlando International Airport and was monitored by a Terminal Doppler Weather Radar (TDWR) located about 10 km south of the airport. The first NASA encounter with this microburst (Event 142), at approximately 2041 UTC, was during its intensification phase. At flight level, in-situ measurements indicated a peak 1-km (averaged) F-factor of approximately 0.1. The second NASA encounter (Event 143) occurred at approximately 2046 UTC, about the time of microburst peak intensity. It was during this penetration that a peak 1-km F-factor of approximately 17 was encountered, which was the largest in-situ measurement of the 1991 summer deployment. By the third encounter (Event 144), at approximately 2051 UTC, the microburst had expanded into a macroburst. During this phase of evolution, an in-situ 1-km F-factor of 0.08 was measured. The focus of this paper is to examine this microburst via numerical simulation from an unsteady, three-dimensional meteorological cloud model. The simulated high-resolution data fields of wind, temperature, radar reflectivity factor, and precipitation are closely examined so as to derive information not readily available from 'observations' and to enhance our understanding of the actual event. Characteristics of the simulated microburst evolution are compared with TDWR and in-situ measurements.

Investigation of the plastic fracture of high strength steels

NASA Technical Reports Server (NTRS)

Cox, T. B.; Low, J. R., Jr.

1972-01-01

An investigation of the plastic fracture process to improve tensile strength in high strength steels is presented. Two generic types of steels are considered: a quenched and tempered grade and a maraging grade, in order to compare two different matrix microstructures. Each type of steel was studied in commercial grade purity and in special melted high purity form, low in residual and impurity elements. The specific alloys dealt with include AISI 4340 and 18 Ni, 200 grade maraging steel, both heat treated to the same yield strength level of approximately 200 ksi.

Antigenic relatedness between glycoproteins of human respiratory syncytial virus subgroups A and B: evaluation of the contributions of F and G glycoproteins to immunity.

PubMed Central

Johnson, P R; Olmsted, R A; Prince, G A; Murphy, B R; Alling, D W; Walsh, E E; Collins, P L

1987-01-01

The degree of antigenic relatedness between human respiratory syncytial virus (RSV) subgroups A and B was estimated from antibody responses induced in cotton rats by respiratory tract infection with RSV. Glycoprotein-specific enzyme-linked immunosorbent assays of antibody responses induced by RSV infection demonstrated that the F glycoproteins of subgroups A and B were antigenically closely related (relatedness, R approximately 50%), whereas the G glycoproteins were only distantly related (R approximately 5%). Intermediate levels of antigenic relatedness (R approximately 25%) were seen in neutralizing antibodies from cotton rats infected with RSV of the two subgroups. Immunity against the F glycoprotein of subgroup A, induced by vaccinia-A2-F, conferred a high level of protection which was of comparable magnitude against challenge by RSV of either subgroup. In comparison, immunity against the G glycoprotein of subgroup A, induced by vaccinia-A2-G, conferred less complete, but significant, protection. Importantly, in vaccinia-A2-G-immunized animals, suppression of homologous challenge virus replication was significantly greater (13-fold) than that observed for the heterologous virus. PMID:3305988

Ecological restoration and its effects on a regional climate: the source region of the Yellow River, China.

PubMed

Li, Zhouyuan; Liu, Xuehua; Niu, Tianlin; Kejia, De; Zhou, Qingping; Ma, Tianxiao; Gao, Yunyang

2015-05-19

The source region of the Yellow River, China, experienced degradation during the 1980s and 1990s, but effective ecological restoration projects have restored the alpine grassland ecosystem. The local government has taken action to restore the grassland area since 1996. Remote sensing monitoring results show an initial restoration of this alpine grassland ecosystem with the structural transformation of land cover from 2000 to 2009 as low- and high-coverage grassland recovered. From 2000 to 2009, the low-coverage grassland area expanded by over 25% and the bare soil area decreased by approximately 15%. To examine the relationship between ecological structure and function, surface temperature (Ts) and evapotranspiration (ET) levels were estimated to study the dynamics of the hydro-heat pattern. The results show a turning point in approximately the year 2000 from a declining ET to a rising ET, eventually reaching the 1990 level of approximately 1.5 cm/day. We conclude that grassland coverage expansion has improved the regional hydrologic cycle as a consequence of ecological restoration. Thus, we suggest that long-term restoration and monitoring efforts would help maintain the climatic adjustment functions of this alpine grassland ecosystem.

Polycyclic aromatic hydrocarbons in mountain soils of the subtropical Atlantic.

PubMed

Ribes, A; Grimalt, J O; Torres García, C J; Cuevas, E

2003-01-01

Surface soil samples from various altitudes on Tenerife Island, ranging from sea level up to 3400 m above mean sea level, were analyzed to study the distribution of 26 polycyclic aromatic hydrocarbons (PAHs) in a remote subtropical area. The stable atmospheric conditions in this island define three vertically stratified layers: marine boundary, trade-wind inversion, and free troposphere. Total PAH concentrations, 1.9 to 6000 microg/kg dry wt., were high when compared with those in tropical areas and in a similar range to those in temperate areas. In the marine boundary layer, fluoranthene (Fla), pyrene (Pyr), benz [a]anthracene (BaA), and chrysene (C + T) were largely dominant. The predominance of Fla over Pyr may reflect photo-oxidative processes during atmospheric transport, although coal combustion inputs cannot be excluded. The PAHs found in higher concentration in the soils from the inversion layer were benzo[b + j]fluoranthene (BbjF) + benzo[k]fluoranthene (BkF) > benzo[e]pyrene (BeP) approximately indeno[1,2, 3-cd]pyrene (Ind) > benzo[a]pyrene (BaP) approximately benzo[ghi]perylene (Bghi) > coronene (Cor) approximately dibenz[a,h]anthracene (Dib), reflecting that high temperatures and insolation prevent the accumulation of PAHs more volatile than BbjF in significant amounts. These climatic conditions involve a process of standardization that prevents the identification of specific PAH sources such as traffic, forest fires, or industrial inputs. Only soils with high total organic carbon (TOC) (e.g., 10-30%) preserve the more volatile compounds such as phenanthrene (Phe), methylphenanthrenes (MPhe), dimethylphenanthrenes (DMPhe), and retene (Ret). However, no relation between PAHs and soil TOC and black carbon (BC) was found. The specific PAH distributions of the free tropospheric region suggest a direct input from pyrolytic processes related to the volcanic emission of gases in Teide.

ATMOS/ATLAS-3 Measurements of Stratospheric Chlorine and Reactive Nitrogen Partitioning Inside and Outside the November 1994 Antarctic Vortex

NASA Technical Reports Server (NTRS)

Rinsland, C. P.; Gunson, M. R.; Salawitch, R. J.; Michelsen, H. A.; Zander, R.; Newchurch, M. J.; Abbas, M. M.; Abrams, M. C.; Manney, G. L.; Chang, A. Y.;

Plasma inhibin A in heifers: relationship with follicle dynamics, gonadotropins, and steroids during the estrous cycle and after treatment with bovine follicular fluid.

PubMed

Bleach, E C; Glencross, R G; Feist, S A; Groome, N P; Knight, P G

2001-03-01

The relationship between follicle growth and plasma inhibin A, FSH, LH, estradiol (E), and progesterone was investigated during the normal bovine estrous cycle and after treatment with steroid-free bovine follicular fluid (bFF) to arrest follicle development. In the first study, four heifers were monitored over three prostaglandin (PG)-synchronized cycles. Blood was collected every 2-8 h, and ovaries were examined daily by ultrasonography. Inhibin A was measured using a modified enzyme-linked immunosorbent assay that employed a new monoclonal antibody against the alpha subunit of bovine inhibin. Plasma inhibin A ( approximately 50 pg/ml before luteolysis) rose steadily during the induced follicular phase (P < 0.05) to a peak ( approximately 125 pg/ml) coincident with the preovulatory E/LH/FSH surge. After ovulation, inhibin A fell sharply (P < 0.05) to a nadir ( approximately 55 pg/ml) coincident with the secondary FSH rise. During the next 3 days, inhibin A increased to approximately 90 pg/ml in association with growth of the new dominant follicle (DF). Plasma E also rose twofold during this period, whereas FSH fell by approximately 50%. Inhibin A was negatively correlated with FSH (r = -0.37, P < 0.001) and positively correlated with E (r = 0.49, P < 0.0001). Observations on eight cycles (two cycles/heifer), in which growth of the ovulatory DF was monitored from emergence to ovulation, showed that the first-wave DF (DF1) ovulated in three cycles and the second-wave DF (DF2) in five cycles. After PG, plasma inhibin A and E increased similarly in both groups, with concomitant falls in FSH. In the former group, the restricted ability of DF1 to secrete both inhibin A and E was restored after luteolysis. Results indicate that dynamic changes in the secretion of both E and inhibin A from the DF contribute to the fall in FSH during the follicular phase and to the generation and termination of the secondary FSH surge, both of which play a key role in follicle selection. In the second study, bFF (two dose levels) was administered to heifers (n = 3-4) for 60 h starting from the time of DF1 emergence. Both doses suppressed FSH (P < 0.05) and blocked DF1 growth to the same extent (P < 0.01), although inhibin A levels were only marginally raised by the lower dose (not significant compared to controls). The high bFF dose raised (P < 0.001) inhibin A to supraphysiological levels ( approximately 1 ng/ml). A large "rebound" rise in FSH occurred within 1 day of stopping both treatments, even though the inhibin A level in the high-dose bFF group was still approximately threefold higher than that in controls. This indicates that desensitization of gonadotropes to inhibin negative feedback is a contributory factor, together with reduced ovarian output of E, in generation of the post-bFF rebound in FSH.

Measuring Burnout Among Psychiatry Clerkship Directors.

PubMed

Rakofsky, Jeffrey J; Dallaghan, Gary Beck; Balon, Richard

2018-02-01

The primary purpose of this study was to determine the prevalence of burnout among Psychiatry clerkship directors. Psychiatry clerkship directors were solicited via email to complete an electronic version of the Maslach Burnout Inventory-General Survey and the Respondent Information Form. Fifty-four out of 110 surveys (49%) were completed. Fourteen percent of respondents scored in the "high exhaustion" category, 21.6% scored in the "low professional efficacy" category, 20.4% scored in the "high cynicism" category, and 15.1% of respondents met threshold for at least two of the three categories. Those who scored in the "low professional efficacy" category reported higher levels of salary support for research, while those who scored in the "high cynicism" category reported lower levels of salary support at a trend level. Those who scored in the "high cynicism" category were younger. Approximately 14-22 percent of psychiatry clerkship directors reported some level of burnout depending on the subscale used. Future studies should aim to better identify those clerkship directors who are at greatest risk for becoming burned out by their educational role and to clarify the link between salary support for research, age, and burnout.

Echolocation signals of wild Atlantic spotted dolphin (Stenella frontalis)

NASA Astrophysics Data System (ADS)

Au, Whitlow W. L.; Herzing, Denise L.

2003-01-01

An array of four hydrophones arranged in a symmetrical star configuration was used to measure the echolocation signals of the Atlantic spotted dolphin (Stenella frontalis) in the Bahamas. The spacing between the center hydrophone and the other hydrophones was 45.7 cm. A video camera was attached to the array and a video tape recorder was time synchronized with the computer used to digitize the acoustic signals. The echolocation signals had bi-modal frequency spectra with a low-frequency peak between 40 and 50 kHz and a high-frequency peak between 110 and 130 kHz. The low-frequency peak was dominant when the signal the source level was low and the high-frequency peak dominated when the source level was high. Peak-to-peak source levels as high as 210 dB re 1 μPa were measured. The source level varied in amplitude approximately as a function of the one-way transmission loss for signals traveling from the animals to the array. The characteristics of the signals were similar to those of captive Tursiops truncatus, Delphinapterus leucas and Pseudorca crassidens measured in open waters under controlled conditions.

Regional distribution of Paenibacillus larvae subspecies larvae, the causative organism of American foulbrood, in honey bee colonies of the Western United States.

PubMed

Eischen, Frank A; Graham, R Henry; Cox, Robert

2005-08-01

We examined honey bee, Apis mellifera L., colonies pollinating almonds in California during February 2003 for Paenibacillus larvae subsp. Larvae, the causative organism of the virulent brood disease American foulbrood. Colonies originating from the Rocky Mountain area and California had significantly higher numbers (P < 0.05) of bacterial colony-forming units (CFUs) (408 and 324 per 30 adult bees, respectively) than colonies from the upper Midwest (1.28). Colonies from the northwestern, central, and southwestern United States had intermediate CFU or bacterial colony levels. Operations positive for P. larvae larvae were relatively uniform at approximately 70-80%, and no regional significant differences were found. Percentages of colonies with high CFUs (> or = 400 per 30 bees) differed significantly, with those from the Rocky Mountain region having 8.73% compared with those of the upper Midwest with 0%. The significance of CFU levels was evaluated by inoculating healthy colonies with diseased immatures and sampling adult bees. The number of CFUs detected per diseased immature was conservatively estimated to be approximately 399 CFUs per 30 adult bees. We defined this spore level as 1 disease equivalent. Based on this, 3.86% colonies in our survey had 1 or more disease equivalent number of P. larvae larvae CFUs. Operations with high P. larvae larvae spore levels in their colonies will likely observe American foulbrood if prophylaxis is not practiced diligently.

Perinatal exposure to low doses of bisphenol A affects body weight, patterns of estrous cyclicity, and plasma LH levels.

PubMed Central

Rubin, B S; Murray, M K; Damassa, D A; King, J C; Soto, A M

2001-01-01

The nonsteroidal estrogenic compound bisphenol A (BPA) is a monomer used in the manufacture of polycarbonate plastics and resins. BPA may be ingested by humans as it reportedly leaches from the lining of tin cans into foods, from dental sealants into saliva, and from polycarbonate bottles into their contents. Because BPA is weakly estrogenic--approximately 10,000-fold less potent than 17beta-estradiol--current environmental exposure levels have been considered orders of magnitude below the dose required for adverse effects on health. Herein we demonstrate measurable effects on the offspring of Sprague-Dawley female rats that were exposed, via their drinking water, to approximately 0.1 mg BPA/kg body weight (bw)/day (low dose) or 1.2 mg BPA/kg bw/day (high dose) from day 6 of pregnancy through the period of lactation. Offspring exposed to BPA exhibited an increase in body weight that was apparent soon after birth and continued into adulthood. In addition, female offspring exposed perinatally to the high dose of BPA exhibited altered patterns of estrous cyclicity and decreased levels of plasma luteinizing hormone (LH) in adulthood. Administration of neither the doses of BPA that caused effects during perinatal exposure nor a 10-fold higher dose was able to evoke a uterotropic response in ovariectomized postpubertal females. These data indicate an increased sensitivity to BPA during the perinatal period and suggest the need for careful evaluation of the current levels of exposure to this compound. PMID:11485865

Biodiversity hotspots house most undiscovered plant species.

PubMed

Joppa, Lucas N; Roberts, David L; Myers, Norman; Pimm, Stuart L

2011-08-09

For most organisms, the number of described species considerably underestimates how many exist. This is itself a problem and causes secondary complications given present high rates of species extinction. Known numbers of flowering plants form the basis of biodiversity "hotspots"--places where high levels of endemism and habitat loss coincide to produce high extinction rates. How different would conservation priorities be if the catalog were complete? Approximately 15% more species of flowering plant are likely still undiscovered. They are almost certainly rare, and depending on where they live, suffer high risks of extinction from habitat loss and global climate disruption. By using a model that incorporates taxonomic effort over time, regions predicted to contain large numbers of undiscovered species are already conservation priorities. Our results leave global conservation priorities more or less intact, but suggest considerably higher levels of species imperilment than previously acknowledged.

Density-dependent blood stage Plasmodium falciparum suppresses malaria super-infection in a malaria holoendemic population.

PubMed

Pinkevych, Mykola; Petravic, Janka; Chelimo, Kiprotich; Vulule, John; Kazura, James W; Moormann, Ann M; Davenport, Miles P

2013-11-01

Recent studies of Plasmodium berghei malaria in mice show that high blood-stage parasitemia levels inhibit the development of subsequent liver-stage infections. Whether a similar inhibitory effect on liver-stage Plasmodium falciparum by blood-stage infection occurs in humans is unknown. We have analyzed data from a treatment-time-to-infection cohort of children < 10 years of age residing in a malaria holoendemic area of Kenya where people experience a new blood-stage infection approximately every 2 weeks. We hypothesized that if high parasitemia blocked the liver stage, then high levels of parasitemia should be followed by a "skipped" peak of parasitemia. Statistical analysis of "natural infection" field data and stochastic simulation of infection dynamics show that the data are consistent with high P. falciparum parasitemia inhibiting liver-stage parasite development in humans.

Eight-Channel AC Magnetosusceptometer of Magnetic Nanoparticles for High-Throughput and Ultra-High-Sensitivity Immunoassay

PubMed Central

Chieh, Jen-Jie; Wei, Wen-Chun; Chen, Hsin-Hsein; Lee, Yen-Fu; Lin, Feng-Chun; Chiang, Ming-Hsien; Chiu, Ming-Jang; Horng, Herng-Er; Yang, Shieh-Yueh

2018-01-01

An alternating-current magnetosusceptometer of antibody-functionalized magnetic nanoparticles (MNPs) was developed for immunomagnetic reduction (IMR). A high-sensitivity, high-critical-temperature superconducting quantum interference device was used in the magnetosusceptometer. Minute levels of biomarkers of early-stage neurodegeneration diseases were detectable in serum, but measuring each biomarker required approximately 4 h. Hence, an eight-channel platform was developed in this study to fit minimal screening requirements for Alzheimer’s disease. Two consistent results were measured for three biomarkers, namely Aβ40, Aβ42, and tau protein, per human specimen. This paper presents the instrument configuration as well as critical characteristics, such as the low noise level variations among channels, a high signal-to-noise ratio, and the coefficient of variation for the biomarkers’ IMR values. The instrument’s ultrahigh sensitivity levels for the three biomarkers and the substantially shorter total measurement time in comparison with the previous single- and four-channels platforms were also demonstrated in this study. Thus, the eight-channel instrument may serve as a powerful tool for clinical high-throughput screening of Alzheimer’s disease. PMID:29601532

Electrostatic Plasma Accelerator (EPA)

NASA Technical Reports Server (NTRS)

Brophy, John R.; Aston, Graeme

1995-01-01

The application of electric propulsion to communications satellites, however, has been limited to the use of hydrazine thrusters with electric heaters for thrust and specific impulse augmentation. These electrothermal thrusters operate at specific impulse levels of approximately 300 s with heater powers of about 500 W. Low power arcjets (1-3 kW) are currently being investigated as a way to increase specific impulse levels to approximately 500 s. Ion propulsion systems can easily produce specific impulses of 3000 s or greater, but have yet to be applied to communications satellites. The reasons most often given for not using ion propulsion systems are their high level of overall complexity, low thrust with long burn times, and the difficulty of integrating the propulsion system into existing commercial spacecraft busses. The Electrostatic Plasma Accelerator (EPA) is a thruster concept which promises specific impulse levels between low power arcjets and those of the ion engine while retaining the relative simplicity of the arcjet. The EPA thruster produces thrust through the electrostatic acceleration of a moderately dense plasma. No accelerating electrodes are used and the specific impulse is a direct function of the applied discharge voltage and the propellant atomic mass.

Dynamics of biomass partitioning, stem gene expression, cell wall biosynthesis, and sucrose accumulation during development of Sorghum bicolor.

PubMed

McKinley, Brian; Rooney, William; Wilkerson, Curtis; Mullet, John

2016-11-01

Biomass accumulated preferentially in leaves of the sweet sorghum Della until floral initiation, then stems until anthesis, followed by panicles until grain maturity, and apical tillers. Sorghum stem RNA-seq transcriptome profiles and composition data were collected for approximately 100 days of development beginning at floral initiation. The analysis identified >200 differentially expressed genes involved in stem growth, cell wall biology, and sucrose accumulation. Genes encoding expansins and xyloglucan endotransglucosylase/hydrolases were differentially expressed in growing stem internodes. Genes encoding enzymes involved in the synthesis of cellulose, lignin, and glucuronoarabinoxylan were expressed at elevated levels in stems until approximately 7 days before anthesis and then down-regulated. CESA genes involved in primary and secondary cell wall synthesis showed different temporal patterns of expression. Following floral initiation, the level of sucrose and other non-structural carbohydrates increased to approximately 50% of the stem's dry weight. Stem sucrose accumulation was inversely correlated with >100-fold down-regulation of SbVIN1, a gene encoding a vacuolar invertase. Accumulation of stem sucrose was also correlated with cessation of leaf and stem growth at anthesis, decreased expression of genes involved in stem cell wall synthesis, and approximately 10-fold lower expression of SbSUS4, a gene encoding sucrose synthase that generates UDP-glucose from sucrose for cell wall biosynthesis. Genes for mixed linkage glucan synthesis (CSLF) and turnover were expressed at high levels in stems throughout development. Overall, the stem transcription profile resource and the genes and regulatory dynamics identified in this study will be useful for engineering sorghum stem composition for improved conversion to biofuels and bio-products. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Deorbitalization strategies for meta-generalized-gradient-approximation exchange-correlation functionals

NASA Astrophysics Data System (ADS)

Mejia-Rodriguez, Daniel; Trickey, S. B.

2017-11-01

We explore the simplification of widely used meta-generalized-gradient approximation (mGGA) exchange-correlation functionals to the Laplacian level of refinement by use of approximate kinetic-energy density functionals (KEDFs). Such deorbitalization is motivated by the prospect of reducing computational cost while recovering a strictly Kohn-Sham local potential framework (rather than the usual generalized Kohn-Sham treatment of mGGAs). A KEDF that has been rather successful in solid simulations proves to be inadequate for deorbitalization, but we produce other forms which, with parametrization to Kohn-Sham results (not experimental data) on a small training set, yield rather good results on standard molecular test sets when used to deorbitalize the meta-GGA made very simple, Tao-Perdew-Staroverov-Scuseria, and strongly constrained and appropriately normed functionals. We also study the difference between high-fidelity and best-performing deorbitalizations and discuss possible implications for use in ab initio molecular dynamics simulations of complicated condensed phase systems.

Individual-based approach to epidemic processes on arbitrary dynamic contact networks

NASA Astrophysics Data System (ADS)

Rocha, Luis E. C.; Masuda, Naoki

2016-08-01

The dynamics of contact networks and epidemics of infectious diseases often occur on comparable time scales. Ignoring one of these time scales may provide an incomplete understanding of the population dynamics of the infection process. We develop an individual-based approximation for the susceptible-infected-recovered epidemic model applicable to arbitrary dynamic networks. Our framework provides, at the individual-level, the probability flow over time associated with the infection dynamics. This computationally efficient framework discards the correlation between the states of different nodes, yet provides accurate results in approximating direct numerical simulations. It naturally captures the temporal heterogeneities and correlations of contact sequences, fundamental ingredients regulating the timing and size of an epidemic outbreak, and the number of secondary infections. The high accuracy of our approximation further allows us to detect the index individual of an epidemic outbreak in real-life network data.

LCAMP: Location Constrained Approximate Message Passing for Compressed Sensing MRI

PubMed Central

Sung, Kyunghyun; Daniel, Bruce L; Hargreaves, Brian A

2016-01-01

Iterative thresholding methods have been extensively studied as faster alternatives to convex optimization methods for solving large-sized problems in compressed sensing. A novel iterative thresholding method called LCAMP (Location Constrained Approximate Message Passing) is presented for reducing computational complexity and improving reconstruction accuracy when a nonzero location (or sparse support) constraint can be obtained from view shared images. LCAMP modifies the existing approximate message passing algorithm by replacing the thresholding stage with a location constraint, which avoids adjusting regularization parameters or thresholding levels. This work is first compared with other conventional reconstruction methods using random 1D signals and then applied to dynamic contrast-enhanced breast MRI to demonstrate the excellent reconstruction accuracy (less than 2% absolute difference) and low computation time (5 - 10 seconds using Matlab) with highly undersampled 3D data (244 × 128 × 48; overall reduction factor = 10). PMID:23042658

Airborne bio-aerosols and noise in a dry waste treatment plant in Pietarsaari, Finland.

PubMed

Tolvanen, O K

2001-04-01

Ewapower Ltd in Pietarsaari, Finland produces pellets from paper and plastic waste for burning. During 1998 and 1999, several measurements were made to determine the dust, particle, microbe and endotoxin concentrations, and also the noise level in the hall where the waste is received and pre-crushed. The noise level exceeded the Finnish recommended level of 85 dBA. The dust and the particle concentrations were low, but the microbe concentrations, especially in the summer and in the autumn, were at a level which may be harmful to health. The total concentration of microbes (both dead and alive) was high--approximately 4.8 million particles m(-3). The concentrations of endotoxins was high in summer and in autumn, from 340 to 1000 ng m(-3) and exceeded recommended values. In the winter, the concentration of the endotoxin was lower, ranging between 4.7 and 33 ng m(-3).

Vacuum Bloch-Siegert shift in Landau polaritons with ultra-high cooperativity

NASA Astrophysics Data System (ADS)

Li, Xinwei; Bamba, Motoaki; Zhang, Qi; Fallahi, Saeed; Gardner, Geoff C.; Gao, Weilu; Lou, Minhan; Yoshioka, Katsumasa; Manfra, Michael J.; Kono, Junichiro

2018-06-01

A two-level system resonantly interacting with an a.c. magnetic or electric field constitutes the physical basis of diverse phenomena and technologies. However, Schrödinger's equation for this seemingly simple system can be solved exactly only under the rotating-wave approximation, which neglects the counter-rotating field component. When the a.c. field is sufficiently strong, this approximation fails, leading to a resonance-frequency shift known as the Bloch-Siegert shift. Here, we report the vacuum Bloch-Siegert shift, which is induced by the ultra-strong coupling of matter with the counter-rotating component of the vacuum fluctuation field in a cavity. Specifically, an ultra-high-mobility two-dimensional electron gas inside a high-Q terahertz cavity in a quantizing magnetic field revealed ultra-narrow Landau polaritons, which exhibited a vacuum Bloch-Siegert shift up to 40 GHz. This shift, clearly distinguishable from the photon-field self-interaction effect, represents a unique manifestation of a strong-field phenomenon without a strong field.

Serotype classification of Streptococcus mutans and its detection outside the oral cavity.

PubMed

Nakano, Kazuhiko; Ooshima, Takashi

2009-09-01

Streptococcus mutans, generally known as a major pathogen of dental caries, is also a possible causative agent of bacteremia and infective endocarditis. S. mutans is classified into serotypes c, e, f and k based on the chemical composition of serotype-specific polysaccharides, with approximately 70-80% of strains found in the oral cavity classified as serotype c, followed by e (approximately 20%), and f and k (less than 5% each). Serotype k was recently designated as a novel serotype and shown to possess unique features, the most prominent being a defect of the glucose side chain in serotype-specific rhamnose-glucose polymers, which is related to a higher incidence of detection in cardiovascular specimens, owing to phagocytosis resistance. Molecular analyses of cardiovascular specimens showed a high detection frequency for S. mutans DNA, among which the detection rate for serotype k was quite high. These findings suggest that serotype k S. mutans possibly has a high level of virulence for systemic diseases.

A reduced-order model from high-dimensional frictional hysteresis

PubMed Central

Biswas, Saurabh; Chatterjee, Anindya

2014-01-01

Hysteresis in material behaviour includes both signum nonlinearities as well as high dimensionality. Available models for component-level hysteretic behaviour are empirical. Here, we derive a low-order model for rate-independent hysteresis from a high-dimensional massless frictional system. The original system, being given in terms of signs of velocities, is first solved incrementally using a linear complementarity problem formulation. From this numerical solution, to develop a reduced-order model, basis vectors are chosen using the singular value decomposition. The slip direction in generalized coordinates is identified as the minimizer of a dissipation-related function. That function includes terms for frictional dissipation through signum nonlinearities at many friction sites. Luckily, it allows a convenient analytical approximation. Upon solution of the approximated minimization problem, the slip direction is found. A final evolution equation for a few states is then obtained that gives a good match with the full solution. The model obtained here may lead to new insights into hysteresis as well as better empirical modelling thereof. PMID:24910522

Field-effect-dependent thermoelectric power in highly resistive Sb2Se3 single nanowire

NASA Astrophysics Data System (ADS)

Sun, Kien Wen; Ko, Ting-Yu; Shellaiah, Muthaiah

2018-04-01

In this paper, we report the results of our experiments on and measurements of electrical resistivity and thermoelectric power (Seebeck coefficient) from single-crystalline antimony triselenide (Sb2Se3) single nanowires (NWs) with high resistivity ( σ 4.37 × 10-4 S/m). A positive Seebeck coefficient of approximately 661 µV/K at room temperature was obtained using a custom-made thermoelectric power probe with an alternating current lock-in method (the 2ω technique), which indicates that the thermal transport is dominated by holes. The measured Seebeck coefficient of the NWs is a factor of 2-3 lower than their bulk counterparts and is comparable to that of a highly conductive Sb2Se3 single NWs (approximately - 750 µV/K). We observed an increase in the Seebeck coefficients with increased bias voltages by field-effect gating, which cannot be explained by the modulation of the Fermi level in the NWs.

Investigation of plant hormone level changes in shoot tips of longan (Dimocarpus longan Lour.) treated with potassium chlorate by liquid chromatography-electrospray ionization mass spectrometry.

PubMed

Susawaengsup, Chanthana; Rayanakorn, Mongkon; Wongpornchai, Sugunya; Wangkarn, Sunanta

2011-08-15

The endogenous levels of indole-3-acetic acid (IAA), gibberellins (GAs), abscisic acid (ABA) and cytokinins (CKs) and their changes were investigated in shoot tips of ten longan (Dimocarpus longan Lour.) trees for off-season flowering until 60 days after potassium chlorate treatment in comparison with those of ten control (untreated) longan trees. These analytes were extracted and interfering matrices removed with a single mixed-mode solid phase extraction under optimum conditions. The recoveries at three levels of concentration were in the range of 72-112%. The endogenous plant hormones were separated and quantified by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). Detection limits based on the signal-to-noise ratio ranged from 10 ng mL(-1) for gibberellin A4 (GA4) to 200 ng mL(-1) for IAA. Within the first week after potassium chlorate treatment, dry weight (DW) amounts in the treated longan shoot tips of four gibberellins, namely: gibberellin A1(GA1), gibberellic acid (GA3), gibberellin A19 (GA19) and gibberellin A20 (GA20), were found to increase to approximately 25, 50, 20 and 60 ng g(-1) respectively, all of which were significantly higher than those of the controls. In contrast, gibberellin A8 (GA8) obtained from the treated longan was found to decrease to approximately 20 ng g(-1)DW while that of the control increased to around 80 ng g(-1)DW. Certain CKs which play a role in leaf bud induction, particularly isopentenyl adenine (iP), isopentenyl adenosine (iPR) and dihydrozeatin riboside (DHZR), were found to be present in amounts of approximately 20, 50 and 60 ng g(-1)DW in the shoot tips of the control longan. The analytical results obtained from the two-month off-season longan flowering period indicate that high GA1, GA3, GA19 and GA20 levels in the longan shoot tips contribute to flower bud induction while high levels of CKs, IAA and ABA in the control longan contribute more to the vegetative development. Copyright © 2011 Elsevier B.V. All rights reserved.

Terahertz quantum cascade lasers based on resonant phonon scattering for depopulation.

PubMed

Hu, Qing; Williams, Benjamin S; Kumar, Sushil; Callebaut, Hans; Reno, John L

2004-02-15

We report our development of terahertz (THz) quantum cascade lasers (QCLs), in which the depopulation of the lower radiative level is achieved through resonant longitudinal optical (LO) phonon scattering. This depopulation mechanism, similar to that implemented in all the QCLs operating at mid-infrared frequencies, is robust at high temperatures and high injection levels. The unique feature of resonant LO-phonon scattering in our THz QCL structures allows a highly selective depopulation of the lower radiative level with a sub-picosecond lifetime, while maintaining a relatively long upper level lifetime (more than 5 ps) that is due to upper-to-ground-state scattering. The first QCL based on this mechanism achieved lasing at 3.4 THz (lambda approximately 87 microm) up to 87 K for pulsed operations, with peak power levels exceeding 10 mW at ca. 40 K. Using a novel double-sided metal waveguide for mode confinement, which yields a unity mode confinement factor and therefore a low total cavity loss at THz frequencies, we have also achieved lasing at wavelengths longer than 100 microm.

In vivo transcription of R-plasmid deoxyribonucleic acid in Escherichia coli strains with altered antibiotic resistance levels and/or conjugal proficiency.

PubMed Central

Davis, R; Vapnek, D

1976-01-01

The amounts of plasmid deoxyribonucleic acid (DNA) and the levels of the in vivo transcription of the Escherichia coli plasmids R538-1 (repressed for conjugal transfer) and R538-1drd (derepressed for transfer) were determined by DNA-DNA hybridization and DNA-ribonucleic acid hybridization, respectively. The results demonstrate that the level of plasmid transcription is increased by two-fold in the strain carrying the derepressed plasmid, compared to an isogenic strain carrying the repressed plasmid, whereas the amount of plasmid DNA is approximately the same, suggesting that the transfer genes are under transcriptional control. Levels of plasmid DNA, plasmid DNA transcription, and chloramphenicol acetyltransferase activity were also compared in a mutant strain that carried the R538-1drd plasmid and was resistant to high levels of antibiotics. This strain produces about 13 copies of plasmid DNA per chromosome compared to five copies for the parent strain. The level of transcription of plasmid DNA was found to be twofold higher in the high-level resistant strain, whereas the level of chloramphenition, acetyltransferase activity was increased by 10-fold. In addition the levels of plasmid DNA transcription and chloramphenicol acetyltransferase activity in the high-level resistant strain were found to be further increased by the presence of high levels of chloramphenicol in the growth medium. The amount of plasmid DNA remained constant under these conditions, indicating that high levels of chloramphenicol can stimulate the expression of plasmid genes at the level of transcription in this strain. PMID:767321

Successful treatment of extreme acute lead intoxication.

PubMed

Mikler, J; Banovcin, P; Jesenak, M; Hamzikova, J; Statelova, D

2009-03-01

Severe acute lead intoxications are rare and are associated with accidental or purposeful ingestion. There were only few cases of severe to fatal poisonings reported in literature in children. We report a case of acute lead intoxication in a child with extremely high lead blood level of 20.4 micromol/L (422.7 microg/dL), who was treated with chelation and in whom significant organ dysfunction did not develop. Documented significant high level above 3.37 micromol/L (corresponding to 70 microg/dL) in this patient persisted for approximately 24 h. Adequate, single or combined chelatation therapy in early phase of acute lead poisoning is essential for the further patient's outcome.

Exposure to grain dust in Great Britain.

PubMed

Spankie, Sally; Cherrie, John W

2012-01-01

Airborne grain dust is a complex mixture of fragments of organic material from grain, plus mineral matter from soil, and possible insect, fungal, or bacterial contamination or their toxic products, such as endotoxin. In the 1990s, grain workers in Britain were frequently exposed to inhalable dust >10 mg.m(-3) (8 h), with particularly high exposures being found at terminals where grain was imported or exported and in drying operations (personal exposure typically approximately 20 mg.m(-3)). Since then, the industry has made substantial progress in improving the control of airborne dust through better-designed processes, increased automation, and an improved focus on product quality. We have used information from the published scientific literature and a small survey of industry representatives to estimate current exposure levels. These data suggest that current long-term exposure to inhalable dust for most workers is on average less than approximately 3 mg.m(-3), with perhaps 15-20% of individual personal exposures being >10 mg.m(-3). There are no published data from Britain on short-term exposure during cleaning and other tasks. We have estimated average levels for a range of tasks and judge that the highest levels, for example during some cleaning activities and certain process tasks such as loading and packing, are probably approximately10 mg.m(-3). Endotoxin levels were judged likely to be <10⁴ EU m(-3) throughout the industry provided inhalable dust levels are <10 mg.m(-3). There are no published exposure data on mycotoxin, respirable crystalline silica, and mite contamination but these are not considered to present widespread problems in the British industry. Further research should be carried out to confirm these findings.

A biphasic dialytic strategy for the treatment of neonatal hyperammonemia

PubMed Central

Avasare, Sonal; Tsai, Eileen; Yadin, Ora; Zaritsky, Joshua

2018-01-01

Background Neonates with inborn errors of metabolism (IEM) often develop hyperammonemia which, if not corrected quickly, may result in poor neurologic outcomes. As pharmacologic therapy cannot rapidly lower ammonia levels, dialysis is frequently required. Both hemodialysis (HD) and standard-dose continuous renal replacement therapy (CRRT) are effective; however, HD may be followed by post-dialytic ammonia rebound, and standard-dose CRRT may not effect a rapid enough decrease in ammonia levels. Case-Diagnosis/Treatment We present two cases of IEM-associated neonatal hyperammonemia in which we employed a biphasic, high-dose CRRT treatment strategy, initially using dialysate flow rates of 5,000 mL/h (approximately 40,000 mL/h/1.73 m2) in order to rapidly decrease ammonia levels, then decreasing the dialysate flow rates to 500 mL/h (approximately 4,000 mL/h/1.73 m2) in order to prevent ammonia rebound. Conclusions This biphasic dialytic treatment strategy for neonatal hyperammonemia effected rapid ammonia reduction without rebound and accomplished during a single dialysis run without equipment changes. PMID:24122260

A neighborhood statistics model for predicting stream pathogen indicator levels.

PubMed

Pandey, Pramod K; Pasternack, Gregory B; Majumder, Mahbubul; Soupir, Michelle L; Kaiser, Mark S

2015-03-01

Because elevated levels of water-borne Escherichia coli in streams are a leading cause of water quality impairments in the U.S., water-quality managers need tools for predicting aqueous E. coli levels. Presently, E. coli levels may be predicted using complex mechanistic models that have a high degree of unchecked uncertainty or simpler statistical models. To assess spatio-temporal patterns of instream E. coli levels, herein we measured E. coli, a pathogen indicator, at 16 sites (at four different times) within the Squaw Creek watershed, Iowa, and subsequently, the Markov Random Field model was exploited to develop a neighborhood statistics model for predicting instream E. coli levels. Two observed covariates, local water temperature (degrees Celsius) and mean cross-sectional depth (meters), were used as inputs to the model. Predictions of E. coli levels in the water column were compared with independent observational data collected from 16 in-stream locations. The results revealed that spatio-temporal averages of predicted and observed E. coli levels were extremely close. Approximately 66 % of individual predicted E. coli concentrations were within a factor of 2 of the observed values. In only one event, the difference between prediction and observation was beyond one order of magnitude. The mean of all predicted values at 16 locations was approximately 1 % higher than the mean of the observed values. The approach presented here will be useful while assessing instream contaminations such as pathogen/pathogen indicator levels at the watershed scale.

Suicide and Students with High-Incidence Disabilities: What Special Educators Need to Know

ERIC Educational Resources Information Center

Wachter, Carrie A.; Bouck, Emily C.

2008-01-01

Suicide is the third leading cause of death in individuals ages 10 to 24. Researchers approximate that 17% to 29% of secondary school students seriously consider suicide and 8% attempt suicide. Students diagnosed with a disability may be at an even higher level of risk than their general education peers. Clearly knowing how to identify and how to…

Gas gun dynamics

NASA Astrophysics Data System (ADS)

Denny, Mark

2013-09-01

The mechanics and thermodynamics of one- and two-stage gas guns are developed. Very high projectile muzzle speed can be obtained by the two-stage version. The physics of simple gas guns, such as air rifles, is accessible to undergraduates and the same level of presentation is used here to understand more complex designs. Numerical solutions to the equations of motion are shown, along with insightful analytic approximations.

Research on Young Women in Computer Science: Promoting High Technology for Girls.

ERIC Educational Resources Information Center

Crombie, Gail

When the public school system of Ontario, Canada, began offering an all-female computer science course for girls in grade 11, female enrollment in computer science increased to approximately 40%. This increased enrollment level has been maintained for 3 years. The new course's effects on girls' attitudes were examined in a survey of 184 grade 11…

Addressing the Needs of Under-Prepared Students in Higher Education: Does College Remediation Work? NBER Working Paper No. 11325

ERIC Educational Resources Information Center

Bettinger, Eric P.; Long, Bridget Terry

2005-01-01

Each year, thousands of students graduate high school academically unprepared for college. As a result, approximately one-third of entering postsecondary students require remedial or developmental work before entering college-level courses. However, little is known about the causal impact of remediation on student outcomes. At an annual cost of…

Higher Order Modulation Intersymbol Interference Caused by Traveling-wave Tube Amplifiers

NASA Technical Reports Server (NTRS)

Kory, Carol L.; Andro, Monty; Williams, W. D. (Technical Monitor)

2002-01-01

For the first time, a time-dependent, physics-based computational model has been used to provide a direct description of the effects of the traveling wave tube amplifier (TWTA) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion; gain and phase ripple; drive-induced oscillations; harmonic generation; intermodulation products; and backward waves, Thus, signal integrity can be investigated in the presence of these sources of potential distortion as a function of the physical geometry and operating characteristics of the high power amplifier and the operational digital signal. This method promises superior predictive fidelity compared to methods using TWT models based on swept-amplitude and/or swept-frequency data. First, the TWT model using the three dimensional (3D) electromagnetic code MAFIA is presented. Then, this comprehensive model is used to investigate approximations made in conventional TWT black-box models used in communication system level simulations, To quantitatively demonstrate the effects these approximations have on digital signal performance predictions, including intersymbol interference (ISI), the MAFIA results are compared to the system level analysis tool, Signal Processing, Workstation (SPW), using high order modulation schemes including 16 and 64-QAM.

Intersymbol Interference Investigations Using a 3D Time-Dependent Traveling Wave Tube Model

NASA Technical Reports Server (NTRS)

Kory, Carol L.; Andro, Monty

2002-01-01

For the first time, a time-dependent, physics-based computational model has been used to provide a direct description of the effects of the traveling wave tube amplifier (TWTA) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion; gain and phase ripple; drive-induced oscillations; harmonic generation; intermodulation products; and backward waves. Thus, signal integrity can be investigated in the presence of these sources of potential distortion as a function of the physical geometry and operating characteristics of the high power amplifier and the operational digital signal. This method promises superior predictive fidelity compared to methods using TWT models based on swept- amplitude and/or swept-frequency data. First, the TWT model using the three dimensional (3D) electromagnetic code MAFIA is presented. Then, this comprehensive model is used to investigate approximations made in conventional TWT black-box models used in communication system level simulations. To quantitatively demonstrate the effects these approximations have on digital signal performance predictions, including intersymbol interference (ISI), the MAFIA results are compared to the system level analysis tool, Signal Processing Workstation (SPW), using high order modulation schemes including 16 and 64-QAM.

HIV testing patterns among urban YMSM of color.

PubMed

Leonard, Noelle R; Rajan, Sonali; Gwadz, Marya V; Aregbesola, Temi

2014-12-01

The heightened level of risk for HIV infection among Black and Latino young men who have sex with men (YMSM) is driven by multilevel influences. Using cross-sectional data, we examined HIV testing patterns among urban YMSM of color in a high-HIV seroprevalence area (ages 16 to 21 years). Self-reported frequency of testing was high, with 42% of youth reporting testing at a greater frequency than recommended guidelines. There were no differences between less frequent and more frequent testers on sexual risk behaviors. Most (80%) youth cited reassurance of HIV-negative status as a reason for testing. Further, over half of the sample reported numerous other reasons for HIV testing, which spanned individual, partner, social, and structural levels of influence. Approximately half of respondents indicated that peers, family members, and counselors influenced their motivation to get tested. Of concern, their first HIV test occurred approximately 2 years after their first sexual experience with another male. These results indicate the need to consider developmental issues as well as comprehensive, multilevel efforts to ensure that YMSM of color test at the Centers for Disease Control and Prevention-recommended frequency but not less than this or too frequently. © 2014 Society for Public Health Education.

Efficient compression of molecular dynamics trajectory files.

PubMed

Marais, Patrick; Kenwood, Julian; Smith, Keegan Carruthers; Kuttel, Michelle M; Gain, James

2012-10-15

We investigate whether specific properties of molecular dynamics trajectory files can be exploited to achieve effective file compression. We explore two classes of lossy, quantized compression scheme: "interframe" predictors, which exploit temporal coherence between successive frames in a simulation, and more complex "intraframe" schemes, which compress each frame independently. Our interframe predictors are fast, memory-efficient and well suited to on-the-fly compression of massive simulation data sets, and significantly outperform the benchmark BZip2 application. Our schemes are configurable: atomic positional accuracy can be sacrificed to achieve greater compression. For high fidelity compression, our linear interframe predictor gives the best results at very little computational cost: at moderate levels of approximation (12-bit quantization, maximum error ≈ 10(-2) Å), we can compress a 1-2 fs trajectory file to 5-8% of its original size. For 200 fs time steps-typically used in fine grained water diffusion experiments-we can compress files to ~25% of their input size, still substantially better than BZip2. While compression performance degrades with high levels of quantization, the simulation error is typically much greater than the associated approximation error in such cases. Copyright © 2012 Wiley Periodicals, Inc.

Asian aerosols: current and year 2030 distributions and implications to human health and regional climate change.

PubMed

Carmichael, Gregory R; Adhikary, Bhupesh; Kulkarni, Sarika; D'Allura, Alessio; Tang, Youhua; Streets, David; Zhang, Qiang; Bond, Tami C; Ramanathan, Veerabhadran; Jamroensan, Aditsuda; Marrapu, Pallavi

2009-08-01

Aerosol distributions in Asia calculated over a 4-year period and constrained by satellite observations of aerosol optical depth (AOD) are presented. Vast regions in Asia that include > 80% of the population have PM2.5 concentrations that exceed on an annual basis the WHO guideline of 10 microg/m3, often by factors of 2 to 4. These high aerosol loadings also have important radiative effects, causing a significant dimming at the surface, and mask approximately 45% of the warming by greenhouse gases. Black carbon (BC) concentrations are high throughout Asia, representing 5-10% of the total AOD, and contributing significantly to atmospheric warming (its warming potential is approximately 55% of that due to CO2). PM levels and AODs in year 2030, estimated based on simulations that consider future changes in emissions, are used to explore opportunities for win-win strategies built upon addressing air quality and climate change together. It is found that in 2030 the PM2.5 levels in significant parts of Asia will increase and exacerbate health impacts; but the aerosols will have a larger masking effect on radiative forcing, due to a decrease in BC and an increase in SO2 emissions.

Evaluation of rate law approximations in bottom-up kinetic models of metabolism.

PubMed

Du, Bin; Zielinski, Daniel C; Kavvas, Erol S; Dräger, Andreas; Tan, Justin; Zhang, Zhen; Ruggiero, Kayla E; Arzumanyan, Garri A; Palsson, Bernhard O

2016-06-06

The mechanistic description of enzyme kinetics in a dynamic model of metabolism requires specifying the numerical values of a large number of kinetic parameters. The parameterization challenge is often addressed through the use of simplifying approximations to form reaction rate laws with reduced numbers of parameters. Whether such simplified models can reproduce dynamic characteristics of the full system is an important question. In this work, we compared the local transient response properties of dynamic models constructed using rate laws with varying levels of approximation. These approximate rate laws were: 1) a Michaelis-Menten rate law with measured enzyme parameters, 2) a Michaelis-Menten rate law with approximated parameters, using the convenience kinetics convention, 3) a thermodynamic rate law resulting from a metabolite saturation assumption, and 4) a pure chemical reaction mass action rate law that removes the role of the enzyme from the reaction kinetics. We utilized in vivo data for the human red blood cell to compare the effect of rate law choices against the backdrop of physiological flux and concentration differences. We found that the Michaelis-Menten rate law with measured enzyme parameters yields an excellent approximation of the full system dynamics, while other assumptions cause greater discrepancies in system dynamic behavior. However, iteratively replacing mechanistic rate laws with approximations resulted in a model that retains a high correlation with the true model behavior. Investigating this consistency, we determined that the order of magnitude differences among fluxes and concentrations in the network were greatly influential on the network dynamics. We further identified reaction features such as thermodynamic reversibility, high substrate concentration, and lack of allosteric regulation, which make certain reactions more suitable for rate law approximations. Overall, our work generally supports the use of approximate rate laws when building large scale kinetic models, due to the key role that physiologically meaningful flux and concentration ranges play in determining network dynamics. However, we also showed that detailed mechanistic models show a clear benefit in prediction accuracy when data is available. The work here should help to provide guidance to future kinetic modeling efforts on the choice of rate law and parameterization approaches.

Resummation of divergent perturbation series: Application to the vibrational states of H2CO molecule

NASA Astrophysics Data System (ADS)

Duchko, A. N.; Bykov, A. D.

2015-10-01

Large-order Rayleigh-Schrödinger perturbation theory (RSPT) is applied to the calculation of anharmonic vibrational energy levels of H2CO molecule. We use the model of harmonic oscillators perturbed by anharmonic terms of potential energy. Since the perturbation series typically diverge due to strong couplings, we apply the algebraic approximation technique because of its effectiveness shown earlier by Goodson and Sergeev [J. Chem. Phys. 110, 8205 (1999); ibid. 124, 094111 (2006)] and in our previous articles [A. D. Bykov et al. Opt. Spectrosc. 114, 396 (2013); ibid. 116, 598 (2014)]. To facilitate the resummation of terms contributing to perturbed states, when resonance mixing between states is especially strong and perturbation series diverge very quick, we used repartition of the Hamiltonian by shifting the normal mode frequencies. Energy levels obtained by algebraic approximants were compared with the results of variational calculation. It was found that for low energy states (up to ˜5000 cm-1), algebraic approximants gave accurate values of energy levels, which were in excellent agreement with the variational method. For highly excited states, strong and multiple resonances complicate series resummation, but a suitable change of normal mode frequencies allows one to reduce the resonance mixing and to get accurate energy levels. The theoretical background of the problem of RSPT series divergence is discussed along with its numerical analysis. For these purposes, the vibrational energy is considered as a function of a complex perturbation parameter. Layout and classification of its singularities allow us to model the asymptotic behavior of the perturbation series and prove the robustness of the algorithm.

Resummation of divergent perturbation series: Application to the vibrational states of H2CO molecule.

PubMed

Duchko, A N; Bykov, A D

2015-10-21

Large-order Rayleigh-Schrödinger perturbation theory (RSPT) is applied to the calculation of anharmonic vibrational energy levels of H2CO molecule. We use the model of harmonic oscillators perturbed by anharmonic terms of potential energy. Since the perturbation series typically diverge due to strong couplings, we apply the algebraic approximation technique because of its effectiveness shown earlier by Goodson and Sergeev [J. Chem. Phys. 110, 8205 (1999); ibid. 124, 094111 (2006)] and in our previous articles [A. D. Bykov et al. Opt. Spectrosc. 114, 396 (2013); ibid. 116, 598 (2014)]. To facilitate the resummation of terms contributing to perturbed states, when resonance mixing between states is especially strong and perturbation series diverge very quick, we used repartition of the Hamiltonian by shifting the normal mode frequencies. Energy levels obtained by algebraic approximants were compared with the results of variational calculation. It was found that for low energy states (up to ∼5000 cm(-1)), algebraic approximants gave accurate values of energy levels, which were in excellent agreement with the variational method. For highly excited states, strong and multiple resonances complicate series resummation, but a suitable change of normal mode frequencies allows one to reduce the resonance mixing and to get accurate energy levels. The theoretical background of the problem of RSPT series divergence is discussed along with its numerical analysis. For these purposes, the vibrational energy is considered as a function of a complex perturbation parameter. Layout and classification of its singularities allow us to model the asymptotic behavior of the perturbation series and prove the robustness of the algorithm.

Return to Work and Sport Following High Tibial Osteotomy: A Systematic Review.

PubMed

Ekhtiari, Seper; Haldane, Chloe E; de Sa, Darren; Simunovic, Nicole; Musahl, Volker; Ayeni, Olufemi R

2016-09-21

The purpose of this study was to examine (1) timelines for return to sport and work following high tibial osteotomy (HTO), and (2) whether patients return to sport and work at levels similar to preoperative levels. A systematic search was conducted across 3 databases (MEDLINE, Embase, and PubMed). Two reviewers independently screened the results for relevant articles. Data regarding patient demographics, indications, surgical technique, return to work and sport, and complication and failure rates were abstracted from eligible studies. Nineteen studies were included, involving 1,189 patients (64% male, 21% female, 15% unspecified) and 1,224 knees. Mean age was 46.2 years (range, 16 to 80 years). Opening-wedge HTO was most commonly used, followed by closing-wedge HTO and hemicallotasis. Mean follow-up was 65.4 months (range, 8 to 253 months). Overall, 87.2% of patients returned to sport postoperatively, and 78.6% returned at an equal or greater level. Among competitive athletes, 54% returned to competition. Overall, 84.5% of patients returned to work postoperatively, and 65.5% returned at an equal or greater level. Approximately 90% of patients who returned to work or sport did so within 1 year. The complication rate was 5.8%, with infection being the most common complication; 7.0% of patients progressed to a total knee arthroplasty at a mean of 6.7 years (range, 0.8 to 15 years) following HTO. The majority of patients undergoing HTO return to sport and work, and most return within 1 year of the operation. Most patients return to sport at a level equal to or greater than the preoperative level. Approximately two-thirds of patients return to an equal or greater level of physical work. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.

Direct application of Padé approximant for solving nonlinear differential equations.

PubMed

Vazquez-Leal, Hector; Benhammouda, Brahim; Filobello-Nino, Uriel; Sarmiento-Reyes, Arturo; Jimenez-Fernandez, Victor Manuel; Garcia-Gervacio, Jose Luis; Huerta-Chua, Jesus; Morales-Mendoza, Luis Javier; Gonzalez-Lee, Mario

2014-01-01

This work presents a direct procedure to apply Padé method to find approximate solutions for nonlinear differential equations. Moreover, we present some cases study showing the strength of the method to generate highly accurate rational approximate solutions compared to other semi-analytical methods. The type of tested nonlinear equations are: a highly nonlinear boundary value problem, a differential-algebraic oscillator problem, and an asymptotic problem. The high accurate handy approximations obtained by the direct application of Padé method shows the high potential if the proposed scheme to approximate a wide variety of problems. What is more, the direct application of the Padé approximant aids to avoid the previous application of an approximative method like Taylor series method, homotopy perturbation method, Adomian Decomposition method, homotopy analysis method, variational iteration method, among others, as tools to obtain a power series solutions to post-treat with the Padé approximant. 34L30.

Absorption in X-ray spectra of high-redshift quasars

NASA Technical Reports Server (NTRS)

Elvis, Martin; Fiore, Fabrizio; Wilkes, Belinda; Mcdowell, Jonathan; Bechtold, Jill

1994-01-01

We present evidence that X-ray absorption is common in high-redshift quasars. We have studied six high-redshift (z approximately 3) quasars with the ROSAT Position Sensitive Proportional Counter (PSPC) of which four are in directions of low Galactic N(sub H). Three out of these four show excess absorption, while only three in approximately 50 z approximately less than 0.4 quasars do, indicating that such absorption must be common, but not ubiquitous, at high redshifts, and that the absorbers must lie at z greater than 0.4. The six quasars were: S5 0014+81, Q0420-388, PKS 0438-436, S4 0636+680. PKS 2000-330, PKS 2126-158, which have redshifts between 2.85 and 3.78. PKS 0438-436 and PKS 2126-158 show evidence for absorption above the local Galactic value at better than 99.999% confidence level. If the absorber is at the redshift of the quasar, then values of N(sub H) = (0.86(+0.49, -0.28)) x 10(exp 22) atoms/sq cm for PKS 0438-436, and N(sub H) = (1.45(+1.20, -0.64)) x 10(exp 22) atoms/ sq cm for PKS 2126-158, are implied, assuming solar abundances. The spectrum of S4 0636+680 also suggests the presence of a similarly large absorption column density at the 98% confidence level. This absorption reverses the trend for the most luminous active galactic nuclei (AGN) to have the least X-ray absorption, so a new mechanism is likely to be responsible. Intervening absorption due to damped Lyman(alpha) systems is a plausible cause. We also suggest, as an intrinsic model, that intracluster material, e.g., a cooling flow, around the quasar could account for both the X-ray spectrum and other properties of these quasars. All the quasars are radio-loud and three are gigahertz peaked (two of the three showing absorption). No excess absorption above the Galactic value is seen toward Q0420-388. This quasar has two damped Lyman(alpha) systems at z = 3.08. The limit on the X-ray column density implies a low ionization fraction, N(H I)/N(H) approximately greater than 4 x 10(exp -3) (3 (sigma)), for solar abundances, for these systems, and can set a weak limit on the size of the absorber. In the emitted frame these PSPC spectra cover the band approximately 0.5-10 keV, which has been well observed for low-redshift quasars and AGN. Comparison of high and low-redshift spectra in this emitted band shows no change of mean spectral index greater than Delta alpha(sub E) greater than 0.3 (99% confidence) with either redshift or luminosity, for radio-loud quasars.

Proposal of a gigawatt-class L/Ku dual-band magnetically insulated transmission line oscillator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ju, J.-C., E-mail: jujinchuan@126.com; Fan, Y.-W.; Shu, T.

2014-10-15

We present a gigawatt (GW)-class magnetically insulated transmission line oscillator (MILO) which is capable of generating dual-band high power microwaves (HPMs). The proposed device, deriving from previously studied complex MILO and dual-frequency MILO, is designed to produce two HPMs in L-band and Ku-band, respectively. It is found in particle-in-cell (PIC) simulation that when the diode voltage is 610 kV, HPMs with frequencies of 1.72 GHz and 14.6 GHz can be achieved with powers of 3.3 GW and 2.4 GW, respectively. The corresponding total power conversion efficiency is approximately 12.8%. Power difference of the two generated HPMs is approximately 1.4 dB, and frequency difference of themmore » reaches a level as high as ∼10 dB.« less

Comparative analysis on inactivation kinetics of between piezotolerant and piezosensitive mutant strains of Saccharomyces cerevisiae under combinations of high hydrostatic pressure and temperature.

PubMed

Nomura, Kazuki; Kuwabara, Yuki; Kuwabara, Wataru; Takahashi, Hiroyuki; Nakajima, Kanako; Hayashi, Mayumi; Iguchi, Akinori; Shigematsu, Toru

2017-12-01

We previously obtained a pressure-tolerant (piezotolerant) and a pressure sensitive (piezosensitive) mutant strain, under ambient temperature, from Saccharomyces cerevisiae strain KA31a. The inactivation kinetics of these mutants were analyzed at 150 to 250MPa with 4 to 40°C. By a multiple regression analysis, the pressure and temperature dependency of the inactivation rate constants k values of both mutants, as well as the parent strain KA31a, were well approximated with high correlation coefficients (0.92 to 0.95). For both mutants, as well as strain KA31a, the lowest k value was shown at a low pressure levels with around ambient temperature. The k value approximately increased with increase in pressure level, and with increase and decrease in temperature. The piezosensitive mutant strain a924E1 showed piezosensitivity at all pressure and temperature levels, compared with the parent strain KA31a. In contrast, the piezotolerant mutant strain a2568D8 showed piezotolerance at 4 to 20°C, but did not show significant piezotolerance at 40°C. These results of the variable influence of temperature on pressure inactivation of these strains would be important for better understanding of piezosensitive and piezotolerant mechanisms, as well as the pressure inactivation mechanism of S. cerevisiae. Copyright © 2017 Elsevier B.V. All rights reserved.

Correction of glucocerebrosidase deficiency after retroviral-mediated gene transfer into hematopoietic progenitor cells from patients with Gaucher disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fink, J.K.; Correll, P.H.; Perry, L.K.

1990-03-01

Retroviral gene transfer has been used successfully to correct the glucocerebrosidase (GCase) deficiency in primary hematopoietic cells from patients with Gaucher disease. For this model of somatic gene therapy, the authors developed a high-titer, amphotropic retroviral vector designated NTG in which the human GCase gene was driven by the mutant polyoma virus enhancer/herpesvirus thymidine kinase gene (tk) promoter (Py{sup +}/Htk). NTG normalized GCase activity in transduced Gaucher fibroblasts and efficiently infected human monocytic and erythroleukemic cell lines. RNA blot-hybridization (Northern blot) analysis of these hemaptopoietic cell lines showed unexpectedly high-level expression from the Moloney murine leukemia virus long terminal repeatmore » (Mo-MLV LTR) and levels of Py{sup +}/Htk enhancer/promoter-initiated human GCase RNA that approximated endogenous GCase RNA levels. Furthermore, NTG efficiently infected human hematopoietic progenitor cells. Detection of the provirus in approximately one-third of NTG-infected progenitor colonies that had not been selected in G418-containing medium indicates that relative resistance to G418 underestimated the actual gene transfer efficiency. Northern blot analysis of NTG-infected, progenitor-derived cells showed expression from both the Mo-MLV LTR and the Py{sup +}/Htk enhancer/promoter. NTG-transduced hematopoietic progenitor cells from patients with Gaucher disease generated progeny in which GCase activity has been normalized.« less

Crystal accumulation in the Hanford Waste Treatment Plant high level waste melter. Preliminary settling and resuspension testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, K. M.; Fowley, M. D.; Miller, D. H.

2016-05-01

The full-scale, room-temperature Hanford Tank Waste Treatment and Immobilization Plant (WTP) High-Level Waste (HLW) melter riser test system was successfully operated with silicone oil and magnetite particles at a loading of 0.1 vol %. Design and construction of the system and instrumentation, and the selection and preparation of simulant materials, are briefly reviewed. Three experiments were completed. A prototypic pour rate was maintained, based on the volumetric flow rate. Settling and accumulation of magnetite particles were observed at the bottom of the riser and along the bottom of the throat after each experiment. The height of the accumulated layer atmore » the bottom of the riser, after the first pouring experiment, approximated the expected level given the solids loading of 0.1 vol %. More detailed observations of particle resuspension and settling were made during and after the third pouring experiment. The accumulated layer of particles at the bottom of the riser appeared to be unaffected after a pouring cycle of approximately 15 minutes at the prototypic flow rate. The accumulated layer of particles along the bottom of the throat was somewhat reduced after the same pouring cycle. Review of the time-lapse recording showed that some of the settling particles flow from the riser into the throat. This may result in a thicker than expected settled layer in the throat.« less

Multiscale stochastic simulations for tensile testing of nanotube-based macroscopic cables.

PubMed

Pugno, Nicola M; Bosia, Federico; Carpinteri, Alberto

2008-08-01

Thousands of multiscale stochastic simulations are carried out in order to perform the first in-silico tensile tests of carbon nanotube (CNT)-based macroscopic cables with varying length. The longest treated cable is the space-elevator megacable but more realistic shorter cables are also considered in this bottom-up investigation. Different sizes, shapes, and concentrations of defects are simulated, resulting in cable macrostrengths not larger than approximately 10 GPa, which is much smaller than the theoretical nanotube strength (approximately 100 GPa). No best-fit parameters are present in the multiscale simulations: the input at level 1 is directly estimated from nanotensile tests of CNTs, whereas its output is considered as the input for the level 2, and so on up to level 5, corresponding to the megacable. Thus, five hierarchical levels are used to span lengths from that of a single nanotube (approximately 100 nm) to that of the space-elevator megacable (approximately 100 Mm).

Spin-orbit splitted excited states using explicitly-correlated equation-of-motion coupled-cluster singles and doubles eigenvectors

NASA Astrophysics Data System (ADS)

Bokhan, Denis; Trubnikov, Dmitrii N.; Perera, Ajith; Bartlett, Rodney J.

2018-04-01

An explicitly-correlated method of calculation of excited states with spin-orbit couplings, has been formulated and implemented. Developed approach utilizes left and right eigenvectors of equation-of-motion coupled-cluster model, which is based on the linearly approximated explicitly correlated coupled-cluster singles and doubles [CCSD(F12)] method. The spin-orbit interactions are introduced by using the spin-orbit mean field (SOMF) approximation of the Breit-Pauli Hamiltonian. Numerical tests for several atoms and molecules show good agreement between explicitly-correlated results and the corresponding values, calculated in complete basis set limit (CBS); the highly-accurate excitation energies can be obtained already at triple- ζ level.

Validity of the two-level approximation in the interaction of few-cycle light pulses with atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng Jing; Zhou Jianying

2003-04-01

The validity of the two-level approximation (TLA) in the interaction of atoms with few-cycle light pulses is studied by investigating a simple (V)-type three-level atom model. Even the transition frequency between the ground state and the third level is far away from the spectrum of the pulse; this additional transition can make the TLA inaccuracy. For a sufficiently large transition frequency or a weak coupling between the ground state and the third level, the TLA is a reasonable approximation and can be used safely. When decreasing the pulse width or increasing the pulse area, the TLA will give rise tomore » non-negligible errors compared with the precise results.« less

Validity of the two-level approximation in the interaction of few-cycle light pulses with atoms

NASA Astrophysics Data System (ADS)

Cheng, Jing; Zhou, Jianying

2003-04-01

The validity of the two-level approximation (TLA) in the interaction of atoms with few-cycle light pulses is studied by investigating a simple V-type three-level atom model. Even the transition frequency between the ground state and the third level is far away from the spectrum of the pulse; this additional transition can make the TLA inaccuracy. For a sufficiently large transition frequency or a weak coupling between the ground state and the third level, the TLA is a reasonable approximation and can be used safely. When decreasing the pulse width or increasing the pulse area, the TLA will give rise to non-negligible errors compared with the precise results.

Advanced ceramic materials for next-generation nuclear applications

NASA Astrophysics Data System (ADS)

Marra, John

2011-10-01

The nuclear industry is at the eye of a 'perfect storm' with fuel oil and natural gas prices near record highs, worldwide energy demands increasing at an alarming rate, and increased concerns about greenhouse gas (GHG) emissions that have caused many to look negatively at long-term use of fossil fuels. This convergence of factors has led to a growing interest in revitalization of the nuclear power industry within the United States and across the globe. Many are surprised to learn that nuclear power provides approximately 20% of the electrical power in the US and approximately 16% of the world-wide electric power. With the above factors in mind, world-wide over 130 new reactor projects are being considered with approximately 25 new permit applications in the US. Materials have long played a very important role in the nuclear industry with applications throughout the entire fuel cycle; from fuel fabrication to waste stabilization. As the international community begins to look at advanced reactor systems and fuel cycles that minimize waste and increase proliferation resistance, materials will play an even larger role. Many of the advanced reactor concepts being evaluated operate at high-temperature requiring the use of durable, heat-resistant materials. Advanced metallic and ceramic fuels are being investigated for a variety of Generation IV reactor concepts. These include the traditional TRISO-coated particles, advanced alloy fuels for 'deep-burn' applications, as well as advanced inert-matrix fuels. In order to minimize wastes and legacy materials, a number of fuel reprocessing operations are being investigated. Advanced materials continue to provide a vital contribution in 'closing the fuel cycle' by stabilization of associated low-level and high-level wastes in highly durable cements, ceramics, and glasses. Beyond this fission energy application, fusion energy will demand advanced materials capable of withstanding the extreme environments of high-temperature plasma systems. Fusion reactors will likely depend on lithium-based ceramics to produce tritium that fuels the fusion plasma, while high-temperature alloys or ceramics will contain and control the hot plasma. All the while, alloys, ceramics, and ceramic-related processes continue to find applications in the management of wastes and byproducts produced by these processes.

Flexible Approximation Model Approach for Bi-Level Integrated System Synthesis

NASA Technical Reports Server (NTRS)

Sobieszczanski-Sobieski, Jaroslaw; Kim, Hongman; Ragon, Scott; Soremekun, Grant; Malone, Brett

2004-01-01

Bi-Level Integrated System Synthesis (BLISS) is an approach that allows design problems to be naturally decomposed into a set of subsystem optimizations and a single system optimization. In the BLISS approach, approximate mathematical models are used to transfer information from the subsystem optimizations to the system optimization. Accurate approximation models are therefore critical to the success of the BLISS procedure. In this paper, new capabilities that are being developed to generate accurate approximation models for BLISS procedure will be described. The benefits of using flexible approximation models such as Kriging will be demonstrated in terms of convergence characteristics and computational cost. An approach of dealing with cases where subsystem optimization cannot find a feasible design will be investigated by using the new flexible approximation models for the violated local constraints.

Flyover noise characteristics of a tilt-wing V/STOL aircraft (XC-142A)

NASA Technical Reports Server (NTRS)

Pegg, R. J.; Henderson, H. R.; Hilton, D. A.

1974-01-01

A field noise measurement investigation was conducted during the flight testing of an XC-142A tilt-wing V/STOL aircraft to define its external noise characteristics. Measured time histories of overall sound pressure level show that noise levels are higher at lower airspeeds and decrease with increased speed up to approximately 160 knots. The primary noise sources were the four high-speed, main propellers. Flyover-noise time histories calculated by existing techniques for propeller noise prediction are in reasonable agreement with the experimental data.

A Comparison of the Readability of Selected Instructions, Publications and Forms Commonly Used by Adults and the Minimum Literacy Level as Defined by the United States Office of Education.

ERIC Educational Resources Information Center

Beris, Carole

The Fry Readability Graph was used to assess the approximate readability level of each of 23 selected instructions, publications, and forms commonly used by adults in order to compare their readability levels with the minimum literacy level as defined by the United States Office of Education (approximately the eighth grade level). The results…

Current and future directions for treating hepatitis B virus infection

PubMed Central

Tawada, Akinobu; Kanda, Tatsuo; Yokosuka, Osamu

2015-01-01

Hepatitis B virus (HBV) persistently infects approximately 350 million people, and approximately 600000 liver-related deaths are observed per year worldwide. HBV infection is also one of the major risk factors for hepatocellular carcinoma (HCC). The persistence of serum hepatitis B e antigen (HBeAg) and high level of serum HBV DNA are thought to reflect a high HBV replication status in hepatocytes, causing cirrhosis, HCC and liver-related deaths. It has been reported that antiviral therapy, such as peginterferon and nucleos(t)ide analogues (NUCs), could suppress liver-related death by inhibiting the HBV DNA levels and inducing seroconversion from HBeAg to antibody to HBe antigen. Currently, peginterferon is widely used, but there are also several disadvantages in the use of peginterferon, such as various adverse events, the administration route and duration. It is difficult to predict the effects of treatment and interferon is contraindicated for the patients with advanced fibrosis of the liver and cirrhosis. With respect to NUCs, entecavir and tenofovir disoproxil fumarate are current the first-choice drugs. NUCs can be administered orally, and their anti-viral effects are stronger than that of peginterferon. However, because cessation of NUC administration leads to high levels of viral replication and causes severe hepatitis, they must be administered for a long time. On the other hand, the use of both interferon and NUCs cannot eliminate covalently closed circular DNA of HBV. In this review, we evaluate the natural course of chronic HBV infection and then provide an outline of these representative drugs, such as peginterferon, entecavir and tenofovir disoproxil fumarate. PMID:26085913

Effects of CO2/HCO3- in perilymph on the endocochlear potential in guinea pigs.

PubMed

Nimura, Yoshitsugu; Mori, Yoshiaki; Inui, Takaki; Sohma, Yoshiro; Takenaka, Hiroshi; Kubota, Takahiro

2007-02-01

The effect of CO(2)/HCO(3)(-) on the endocochlear potential (EP) was examined by using both ion-selective and conventional microelectrodes and the endolymphatic or perilymphatic perfusion technique. The main findings were as follows: (i) A decrease in the EP from approximately +75 to approximately +35 mV was produced by perilymphatic perfusion with CO(2)/HCO(3)(-)-free solution, which decrease was accompanied by an increase in the endolymphatic pH (DeltapH(e), approximately 0.4). (ii) Perilymphatic perfusion with a solution containing 20 mM NH(4)Cl produced a decrease in the EP (DeltaEP, approximately 20 mV) with an increase in the pH(e) (DeltapH(e), approximately 0.2), whereas switching the perfusion solution from the NH(4)Cl solution to a 5% CO(2)/25 mM HCO(3)(-) solution produced a gradual increase in the EP to the control level with the concomitant recovery of the pH(e). (iii) The perfusion with a solution of high or low HCO(3)(-) with a constant CO(2) level within 10 min produced no significant changes in the EP. (iv) Perfusion of the perilymph with 10 microg/ml nifedipine suppressed the transient asphyxia-induced decrease in EP slightly, but not significantly. (v) By contrast, the administration of 1 microg/ml nifedipine via the endolymph inhibited significantly the reduction in the EP induced by transient asphyxia or perilymphatic perfusion with CO(2)/HCO(3)(-)-free or 20 mM NH(4)Cl solution. These findings suggest that the effect of CO(2) removal from perilymphatic perfusion solution on the EP may be mediated by an increase in cytosolic Ca(2+) concentration induced by an elevation of cytosolic pH in endolymphatic surface cells.

Origin of the quasiparticle peak in the spectral density of Cr(001) surfaces

NASA Astrophysics Data System (ADS)

Peters, L.; Jacob, D.; Karolak, M.; Lichtenstein, A. I.; Katsnelson, M. I.

2017-12-01

In the spectral density of Cr(001) surfaces, a sharp resonance close to the Fermi level is observed in both experiment and theory. For the physical origin of this peak, two mechanisms were proposed: a single-particle dz2 surface state renormalized by electron-phonon coupling and an orbital Kondo effect due to the degenerate dx z/dy z states. Despite several experimental and theoretical investigations, the origin is still under debate. In this work, we address this problem by two different approaches of the dynamical mean-field theory: first, by the spin-polarized T -matrix fluctuation exchange approximation suitable for weakly and moderately correlated systems; second, by the noncrossing approximation derived in the limit of weak hybridization (i.e., for strongly correlated systems) capturing Kondo-type processes. By using recent continuous-time quantum Monte Carlo calculations as a benchmark, we find that the high-energy features, everything except the resonance, of the spectrum are captured within the spin-polarized T -matrix fluctuation exchange approximation. More precisely, the particle-particle processes provide the main contribution. For the noncrossing approximation, it appears that spin-polarized calculations suffer from spurious behavior at the Fermi level. Then, we turned to non-spin-polarized calculations to avoid this unphysical behavior. By employing two plausible starting hybridization functions, it is observed that the characteristics of the resonance are crucially dependent on the starting point. It appears that only one of these starting hybridizations could result in an orbital Kondo resonance in the presence of a strong magnetic field like in the Cr(001) surface. It is for a future investigation to first resolve the unphysical behavior within the spin-polarized noncrossing approximation and then check for an orbital Kondo resonance.

Spreading out or concentrating weekly consumption: alcohol problems and other consequences within a UK population sample.

PubMed

Miller, Patrick; Plant, Moira; Plant, Martin

2005-01-01

To consider the consequences, within a UK population sample, of consuming a given amount of alcohol weekly in one or two sessions as against spreading it out over several sessions. A new analysis of data from the UK components of the GENACIS survey of adults aged > or =18, was carried out. At low levels of weekly alcohol consumption those subjects whose usual drinking frequency was several times per week ('spreaders'), if anything, reported more alcohol problems than those who consumed alcohol only once or twice per week ('bingers'). As weekly consumption increased above approximately 11 units per week 'bingers' began to experience more problems than 'spreaders'. At the highest levels of consumption 'bingers' reported more positive experiences from drinking than did 'spreaders'. Subjects >54 years showed lower levels of weekly alcohol consumption than other subjects, and relationships between problems, drinking level, and drinking pattern were less in evidence. Females drank less alcohol and experienced fewer alcohol-related problems than did their male counterparts. However, at high-consumption levels, female 'bingers' experienced fewer problems than male 'bingers'. For most but not all the variables studied, both drinking level and drinking pattern are important determinants of problems experienced. Binge drinking for people who drink more than approximately 11 units per week is an obvious target for harm minimization.

Optimization and physicochemical characterization of a triamcinolone acetonide-loaded NLC for ocular antiangiogenic applications.

PubMed

Araújo, J; Gonzalez-Mira, E; Egea, M A; Garcia, M L; Souto, E B

2010-06-30

The purpose of this study was to develop a novel nanostructured lipid carrier (NLC) for the intravitreal-targeting delivery of triamcinolone acetonide (TA) by direct ocular instillation. A five-level central composite rotable design was used to study the influence of four different variables on the physicochemical characteristics of NLCs. The analysis of variance (ANOVA) statistical test was used to assess the optimization of NLC production parameters. The systems were produced by high pressure homogenization using Precirol ATO5 and squalene as solid and liquid lipids respectively, and Lutrol F68 as surfactant. Homogenization at 600 bar for 3 cycles of the optimized formulation resulted in the production of small NLC (mean diameter < 200 nm) with a homogeneous particle size distribution (polydispersity index (PI) approximately 0.1), of negatively charged surface (approximately |45| mV) and high entrapment efficiency (approximately 95%). Surface morphology was assessed by SEM which revealed fairly spherical shape. DSC, WAXS and FT-IR analyses confirmed that TA was mostly entrapped into the NLC, characterized by an amorphous matrix. In vivo Draize test showed no signs of ocular toxicity. 2010 Elsevier B.V. All rights reserved.

Studies of discharge mechanisms in high pressure gases-applications to high efficiency high power lasers. Ph.D. Thesis. Semiannual Progress Report

NASA Technical Reports Server (NTRS)

Cherrington, B. E.; Verdeyen, J. T.; Eden, J. G.; Leslie, S. G.

1975-01-01

By measuring the absorption and emission cantinua of various states in the cesium/xenon molecule, the collisional rates critical in populating the alkali/rare gas excimer levels have been estimated. Cs atomic states that are weakly optically connected to ground have been shown to form excimer levels that are attractive as potential dissociation lasers. In particular, the (Cs/7 2S/Xe) excited molecule appears promising as a source of high energy laser radiation due to its large dissociation energy, stimulated emission cross section, and small population inversion densities. Monitoring of the optically pumped Cs2 molecular absorption profile in the presence of xenon shows a drastic change with increasing xenon pressure for the Cs2C band. Dominant absorption at large xenon densities is centered around approximately 6380 A as opposed to 6300 A for lower perturber pressure.

A two-level stochastic collocation method for semilinear elliptic equations with random coefficients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Luoping; Zheng, Bin; Lin, Guang

In this work, we propose a novel two-level discretization for solving semilinear elliptic equations with random coefficients. Motivated by the two-grid method for deterministic partial differential equations (PDEs) introduced by Xu, our two-level stochastic collocation method utilizes a two-grid finite element discretization in the physical space and a two-level collocation method in the random domain. In particular, we solve semilinear equations on a coarse meshmore » $$\\mathcal{T}_H$$ with a low level stochastic collocation (corresponding to the polynomial space $$\\mathcal{P}_{P}$$) and solve linearized equations on a fine mesh $$\\mathcal{T}_h$$ using high level stochastic collocation (corresponding to the polynomial space $$\\mathcal{P}_p$$). We prove that the approximated solution obtained from this method achieves the same order of accuracy as that from solving the original semilinear problem directly by stochastic collocation method with $$\\mathcal{T}_h$$ and $$\\mathcal{P}_p$$. The two-level method is computationally more efficient, especially for nonlinear problems with high random dimensions. Numerical experiments are also provided to verify the theoretical results.« less

Assessing water scarcity in agricultural production system based on the generalized water resources and water footprint framework.

PubMed

Xinchun, Cao; Mengyang, Wu; Xiangping, Guo; Yalian, Zheng; Yan, Gong; Nan, Wu; Weiguang, Wang

2017-12-31

An indicator, agricultural water stress index (AWSI), was established based blue-green water resources and water footprint framework for regional water scarcity in agricultural production industry evaluation. AWSI is defined as the ratio of the total agricultural water footprint (AWF) to water resources availability (AWR) in a single year. Then, the temporal and spatial patterns of AWSI in China during 1999-2014 were analyzed based on the provincial AWR and AWF quantification. The results show that the annual AWR in China has been maintained at approximately 2540Gm 3 , of which blue water accounted for >70%. The national annual AWF was approximately 1040Gm 3 during the study period and comprised 65.6% green, 12.7% blue and 21.7% grey WFs The space difference in both the AWF for per unit arable land (AWFI) and its composition was significant. National AWSI was calculated as 0.413 and showed an increasing trend in the observed period. This index increased from 0.320 (mid-water stress level) in 2000 to 0.490 (high water stress level) in the present due to the expansion of the agricultural production scale. The Northern provinces, autonomous regions and municipalities (PAMs) have been facing high water stress, particularly the Huang-Huai-Hai Plain, which was at a very high water stress level (AWSI>0.800). Humid South China faces increasingly severe water scarcity, and most of the PAMs in the region have converted from low water stress level (AWSI=0.100-0.200) to mid water stress level (AWSI=0.200-0.400). The AWSI is more appropriate for reflecting the regional water scarcity than the existing water stress index (WSI) or the blue water scarcity (BWS) indicator, particularly for the arid agricultural production regions due to the revealed environmental impacts of agricultural production. China should guarantee the sustainable use of agricultural water resources by reducing its crop water footprint. Copyright © 2017 Elsevier B.V. All rights reserved.

Growth and survival of Salmonella in ground black pepper (Piper nigrum).

PubMed

Keller, Susanne E; VanDoren, Jane M; Grasso, Elizabeth M; Halik, Lindsay A

2013-05-01

A four serovar cocktail of Salmonella was inoculated into ground black pepper (Piper nigrum) at different water activity (aw) levels at a starting level of 4-5 log cfu/g and incubated at 25 and at 35 °C. At 35 °C and aw of 0.9886 ± 0.0006, the generation time in ground black pepper was 31 ± 3 min with a lag time of 4 ± 1 h. Growth at 25 °C had a longer lag, but generation time was not statistically different from growth at 35 °C. The aw threshold for growth was determined to be 0.9793 ± 0.0027 at 35 °C. To determine survival during storage conditions, ground black pepper was inoculated at approximately 8 log cfu/g and stored at 25 and 35 °C at high (97% RH) and ambient (≤40% RH) humidity. At high relative humidity, aw increased to approximately 0.8-0.9 after approximately 20 days at both temperatures and no Salmonella was detected after 100 and 45 days at 25 and 35 °C, respectively. Under ambient humidity, populations showed an initial decrease of 3-4 log cfu/g, then remained stable for over 8 months at 25 and 35 °C. Results of this study indicate Salmonella can readily grow at permissive aw in ground black pepper and may persist for an extended period of time under typical storage conditions. Published by Elsevier Ltd.

Discrete wavelet transform: a tool in smoothing kinematic data.

PubMed

Ismail, A R; Asfour, S S

1999-03-01

Motion analysis systems typically introduce noise to the displacement data recorded. Butterworth digital filters have been used to smooth the displacement data in order to obtain smoothed velocities and accelerations. However, this technique does not yield satisfactory results, especially when dealing with complex kinematic motions that occupy the low- and high-frequency bands. The use of the discrete wavelet transform, as an alternative to digital filters, is presented in this paper. The transform passes the original signal through two complementary low- and high-pass FIR filters and decomposes the signal into an approximation function and a detail function. Further decomposition of the signal results in transforming the signal into a hierarchy set of orthogonal approximation and detail functions. A reverse process is employed to perfectly reconstruct the signal (inverse transform) back from its approximation and detail functions. The discrete wavelet transform was applied to the displacement data recorded by Pezzack et al., 1977. The smoothed displacement data were twice differentiated and compared to Pezzack et al.'s acceleration data in order to choose the most appropriate filter coefficients and decomposition level on the basis of maximizing the percentage of retained energy (PRE) and minimizing the root mean square error (RMSE). Daubechies wavelet of the fourth order (Db4) at the second decomposition level showed better results than both the biorthogonal and Coiflet wavelets (PRE = 97.5%, RMSE = 4.7 rad s-2). The Db4 wavelet was then used to compress complex displacement data obtained from a noisy mathematically generated function. Results clearly indicate superiority of this new smoothing approach over traditional filters.

High Levels of Decisional Conflict and Decision Regret When Making Decisions About Biologics.

PubMed

Lipstein, Ellen A; Lovell, Daniel J; Denson, Lee A; Kim, Sandra C; Spencer, Charles; Ittenbach, Richard F; Britto, Maria T

2016-12-01

The aim of the study was to understand the association between parents' perceptions of the decision process and the decision outcomes in decisions about the use of biologics in pediatric chronic conditions. We mailed surveys to parents of children with inflammatory bowel disease or juvenile idiopathic arthritis who had started treatment with biologics in the prior 2 years and were treated at either of 2 children's hospitals. The survey included measures of the decision process, including decision control and physician engagement, and decision outcomes, including conflict and regret. We used means and frequencies to assess the response distributions. General linear models were used to test the associations between decision process and decision outcomes. We had 201 respondents (response rate 54.9%). Approximately 47.0% reported using shared decision making. Each physician engagement behavior was experienced by the majority of parents, with the highest percentage reporting that their child's physician used language they understood and listened to them. Approximately 48.5% of parents had decisional conflict scores of 25 or greater, indicating high levels of conflict. Approximately 28.2% had no regret, 31.8% had mild regret, and the remaining 40.0% had moderate to severe regret. Shared decision making was not associated with improved decisional conflict, but physician engagement behaviors were associated with both decisional conflict and regret. Improving decision outcomes will require more than just focusing on who parents perceive as controlling the final decision. Developing interventions that facilitate specific physician engagement behaviors may decrease parents' distress around decision making and improve decision outcomes.

The X-ray absorption spectrum of 4U1700-37 and its implications for the stellar wind of the companion HD153919

NASA Technical Reports Server (NTRS)

White, N. E.; Kallman, T. R.; Swank, J. H.

1982-01-01

The first high resolution non-dispersive 2-60 KeV X-ray spectra of 4U1700-37 is presented. The continuum is typical of that found from X-ray pulsars; that is a flat power law between 2 and 10 keV and, beyond 10 keV, an exponential decay of characteristic energy varying between 10 and 20 keV. No X-ray pulsations were detected between 160 ms and 6 min with an amplitude greater than approximately 2%. The absorption measured at binary phases approximately 0.72 is comparable to that expected from the stellar wind of the primary. The gravitational capture of material in the wind is found to be more than enough to power the X-ray source. The increase in the average absorption after phi o approximately 0.5 is confirmed. The minimum level of adsorption is a factor of 2 or 3 lower than that reported by previous observers, which may be related to a factor of approximately 10 decline in the average X-ray luminosity over the same interval. Short term approximately 50% variations in adsorption are seen for the first time which appear to be loosely correlated with approximately 10 min flickering activity in the X-ray flux. These most likely originate from inhomogeneities in the stellar wind of the primary.

The rise and fall of an ancient Adélie penguin `supercolony' at Cape Adare, Antarctica

NASA Astrophysics Data System (ADS)

Emslie, Steven D.; McKenzie, Ashley; Patterson, William P.

2018-04-01

We report new discoveries and radiocarbon dates on active and abandoned Adélie penguin (Pygoscelis adeliae) colonies at Cape Adare, Antarctica. This colony, first established at approximately 2000 BP (calendar years before present, i.e. 1950), is currently the largest for this species with approximately 338 000 breeding pairs, most located on low-lying Ridley Beach. We hypothesize that this colony first formed after fast ice began blocking open-water access by breeding penguins to the Scott Coast in the southern Ross Sea during a cooling period also at approximately 2000 BP. Our results suggest that the new colony at Cape Adare continued to grow, expanding to a large upper terrace above Ridley Beach, until it exceeded approximately 500 000 breeding pairs (a `supercolony') by approximately 1200 BP. The high marine productivity associated with the Ross Sea polynya and continental shelf break supported this growth, but the colony collapsed to its present size for unknown reasons after approximately 1200 BP. Ridley Beach will probably be abandoned in the near future due to rising sea level in this region. We predict that penguins will retreat to higher elevations at Cape Adare and that the Scott Coast will be reoccupied by breeding penguins as fast ice continues to dissipate earlier each summer, restoring open-water access to beaches there.

The rise and fall of an ancient Adélie penguin 'supercolony' at Cape Adare, Antarctica.

PubMed

Emslie, Steven D; McKenzie, Ashley; Patterson, William P

2018-04-01

We report new discoveries and radiocarbon dates on active and abandoned Adélie penguin ( Pygoscelis adeliae ) colonies at Cape Adare, Antarctica. This colony, first established at approximately 2000 BP (calendar years before present, i.e. 1950), is currently the largest for this species with approximately 338 000 breeding pairs, most located on low-lying Ridley Beach. We hypothesize that this colony first formed after fast ice began blocking open-water access by breeding penguins to the Scott Coast in the southern Ross Sea during a cooling period also at approximately 2000 BP. Our results suggest that the new colony at Cape Adare continued to grow, expanding to a large upper terrace above Ridley Beach, until it exceeded approximately 500 000 breeding pairs (a 'supercolony') by approximately 1200 BP. The high marine productivity associated with the Ross Sea polynya and continental shelf break supported this growth, but the colony collapsed to its present size for unknown reasons after approximately 1200 BP. Ridley Beach will probably be abandoned in the near future due to rising sea level in this region. We predict that penguins will retreat to higher elevations at Cape Adare and that the Scott Coast will be reoccupied by breeding penguins as fast ice continues to dissipate earlier each summer, restoring open-water access to beaches there.

The rise and fall of an ancient Adélie penguin ‘supercolony’ at Cape Adare, Antarctica

PubMed Central

McKenzie, Ashley; Patterson, William P.

2018-01-01

We report new discoveries and radiocarbon dates on active and abandoned Adélie penguin (Pygoscelis adeliae) colonies at Cape Adare, Antarctica. This colony, first established at approximately 2000 BP (calendar years before present, i.e. 1950), is currently the largest for this species with approximately 338 000 breeding pairs, most located on low-lying Ridley Beach. We hypothesize that this colony first formed after fast ice began blocking open-water access by breeding penguins to the Scott Coast in the southern Ross Sea during a cooling period also at approximately 2000 BP. Our results suggest that the new colony at Cape Adare continued to grow, expanding to a large upper terrace above Ridley Beach, until it exceeded approximately 500 000 breeding pairs (a ‘supercolony’) by approximately 1200 BP. The high marine productivity associated with the Ross Sea polynya and continental shelf break supported this growth, but the colony collapsed to its present size for unknown reasons after approximately 1200 BP. Ridley Beach will probably be abandoned in the near future due to rising sea level in this region. We predict that penguins will retreat to higher elevations at Cape Adare and that the Scott Coast will be reoccupied by breeding penguins as fast ice continues to dissipate earlier each summer, restoring open-water access to beaches there. PMID:29765656

Gamma-Ray Spectra and Variability of Cygnus Z-1 Observed by BATSE

NASA Technical Reports Server (NTRS)

Ling, J. C.; Wheaton, William A.; Wallyn, P.; Mahoney, W. .; Paciesas, W. S.; Harmon, B. A.; Fishman, G. J.; Zhang, S. N.; Hua, X. M.

1998-01-01

We present new BATSE earth occultation observations of the 25 keV-1.8 MeV spectrum and variability of Cygnus X-1 made between August 1993 and May 1994. We observed that the normal soft gamma ray spectrum (gamma2) of Cygnus X-1 has two components: a Comptonized part seen below 300 keV, and a high-energy tail in the 0.3 - 2 MeV range. We interpret it in terms of a two-layer region, consisting of a high-energy core (with an equivalent electron temperature of approximately 210-250 keV) near the event horizon, embedded in an about 50 keV corona. In this scenario, the observed 25-300 keV photons were produced by Compton scattering of soft photons (about 0.5 keV) by the hot electrons in the outer corona. These same hard x rays were further up-scattered by a population of energetic electrons in the inner core, producing the spectral tail above 300 keV. Cygnus X-1 went through an extended sequence of transitions between August 1993 and May 1994, when the 45-140 keV flux first decreased steadily from approximately gamma2 to roughly one-quarter of its intensity over a period of about 140 days. The flux remained at this low level for about 40 days before returning, swiftly (approximately 20 days) to approximately the initial gamma2 level. During the transition, the spectrum evolved to a shape consistent with either a power law with photon index of about 2.6 or a single temperature Compton model with electron temperature kT = 110 +/- 11 keV, and optical depth t = 0.40 +/- 0.06, and then returned essentially to the original gamma2 spectrum at the end of the active period. The overall cooling of the system during the low flux period may be due to an increase in the soft photon population which effectively quenched the hot electrons in these regions through Compton scattering.

Obliquity-paced Pliocene West Antarctic ice sheet oscillations.

PubMed

Naish, T; Powell, R; Levy, R; Wilson, G; Scherer, R; Talarico, F; Krissek, L; Niessen, F; Pompilio, M; Wilson, T; Carter, L; DeConto, R; Huybers, P; McKay, R; Pollard, D; Ross, J; Winter, D; Barrett, P; Browne, G; Cody, R; Cowan, E; Crampton, J; Dunbar, G; Dunbar, N; Florindo, F; Gebhardt, C; Graham, I; Hannah, M; Hansaraj, D; Harwood, D; Helling, D; Henrys, S; Hinnov, L; Kuhn, G; Kyle, P; Läufer, A; Maffioli, P; Magens, D; Mandernack, K; McIntosh, W; Millan, C; Morin, R; Ohneiser, C; Paulsen, T; Persico, D; Raine, I; Reed, J; Riesselman, C; Sagnotti, L; Schmitt, D; Sjunneskog, C; Strong, P; Taviani, M; Vogel, S; Wilch, T; Williams, T

2009-03-19

Thirty years after oxygen isotope records from microfossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth's orbital geometry control the ice ages, fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles. Furthermore, an understanding of the behaviour of the marine-based West Antarctic ice sheet (WAIS) during the 'warmer-than-present' early-Pliocene epoch ( approximately 5-3 Myr ago) is needed to better constrain the possible range of ice-sheet behaviour in the context of future global warming. Here we present a marine glacial record from the upper 600 m of the AND-1B sediment core recovered from beneath the northwest part of the Ross ice shelf by the ANDRILL programme and demonstrate well-dated, approximately 40-kyr cyclic variations in ice-sheet extent linked to cycles in insolation influenced by changes in the Earth's axial tilt (obliquity) during the Pliocene. Our data provide direct evidence for orbitally induced oscillations in the WAIS, which periodically collapsed, resulting in a switch from grounded ice, or ice shelves, to open waters in the Ross embayment when planetary temperatures were up to approximately 3 degrees C warmer than today and atmospheric CO(2) concentration was as high as approximately 400 p.p.m.v. (refs 5, 6). The evidence is consistent with a new ice-sheet/ice-shelf model that simulates fluctuations in Antarctic ice volume of up to +7 m in equivalent sea level associated with the loss of the WAIS and up to +3 m in equivalent sea level from the East Antarctic ice sheet, in response to ocean-induced melting paced by obliquity. During interglacial times, diatomaceous sediments indicate high surface-water productivity, minimal summer sea ice and air temperatures above freezing, suggesting an additional influence of surface melt under conditions of elevated CO(2).

Climatology of the autumn Red Sea trough

NASA Astrophysics Data System (ADS)

Awad, Adel M.; Mashat, Abdul-Wahab S.

2018-03-01

In this study, the Sudan low and the associated Red Sea trough (RST) are objectively identified using the mean sea level pressure (SLP) data from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis dataset covering the period 1955-2015. The Sudan low was detected in approximately 60.6% of the autumn periods, and approximately 83% of the detected low-pressure systems extended into RSTs, with most generated at night and during cold months. The distribution of the RSTs demonstrated that Sudan, South Sudan and Red Sea are the primary development areas of the RSTs, generating 97% of the RSTs in the study period. In addition, the outermost areas affected by RSTs, which include the southern, central and northern Red Sea areas, received approximately 91% of the RSTs originating from the primary generation areas. The synoptic features indicated that a Sudan low developed into an RST when the Sudan low deepened in the atmosphere, while the low pressures over the southern Arabian Peninsula are shallow and the anticyclonic systems are weakened over the northern Red Sea. Moreover, stabile areas over Africa and Arabian Peninsula form a high stability gradient around the Red Sea and the upper maximum winds weaken. The results of the case studies indicate that RSTs extend northward when the upper cyclonic and anticyclonic systems form a high geopotential gradient over Arabian Peninsula. Furthermore, the RST is oriented from the west to the east when the Azores high extends eastward and the Siberian high shrinks eastward or shifts northward.

Dependence on glucose limitation of the pCO2 influences on CHO cell growth, metabolism and IgG production.

PubMed

Takuma, Shinya; Hirashima, Chikashi; Piret, James M

2007-08-15

The culture levels of glucose and CO(2) have been reported to independently have important influences on mammalian cell processes. In this work the combined effects of glucose limitation and CO(2) partial pressure (pCO(2)) on monoclonal antibody (IgG) producing Chinese Hamster Ovary cells were investigated in a perfusion reactor operated with controlled cell specific medium feed rate, pH and osmolality. Under high glucose conditions (14.3 +/- 0.8 mM), the apparent growth rate decreased (from 0.021 to 0.009 h(-1)) as the pCO(2) increased to approximately 220 mmHg, while the cell specific IgG productivity was almost unchanged. The lactate yield from glucose was not affected by pCO(2) up to approximately 220 mmHg and glucose was mainly converted to lactate. A feed medium modification from high (33 mM) to low (6 mM) glucose resulted in <0.1 mM glucose in the culture. As a result of apparently shifting metabolism towards the conversion of pyruvate to CO(2), both the ratio of lactate to glucose and the alanine production rate were lowered (1.51-1.14 and 17.7-0.56 nmol/10(6) cells h, respectively). Interestingly, when the pCO(2) was increased to approximately 140 mmHg, limiting glucose resulted in 1.7-fold higher growth rates, compared to high glucose conditions. However, at approximately 220 mmHg pCO(2) this beneficial effect of glucose limitation on these CHO cells was lost as the growth rate dropped dramatically to 0.008 h(-1) and the IgG productivity was lowered by 15% (P < 0.01) relative to the high glucose condition. The IgG galactosylation increased under glucose- limited compared to high-glucose conditions. (c) 2007 Wiley Periodicals, Inc.

Small world, big results : nanotechnology and forest products are teaming up to create the ?material of the 21st century?-?coated paper and paperboard

Treesearch

Phil Jones; T. H. Wegner

2007-01-01

At its fundamental level, wood is made up of nanodimensional cellulose nanocrystalline fibrils that have extremely high strength?approximately 25% the strength of carbon nanotubes. Because of this, plus our emerging ability to manipulate cell wall nano- dimensional architecture and functionality, the abundance of lignocellulosic materials, and our emerging ability to...

CBP [TASK 12] experimental study of the concrete salstone two-layer system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samson, Eric; Protiere, Yannick

This report presents the results of a study which intended to study the behavior of concrete samples placed in contact with a wasteform mixture bearing high level of sulfate in its pore solution. A setup was prepared which consisted in a wasteform poured on top of vault concrete mixes (identified as Vault 1/4 and Vault 2 mixes) cured for approximately 6 months.

The Effect of Pictures and Humor on Memory for Verbal Material in Two Extreme Scholastic Aptitude Populations.

ERIC Educational Resources Information Center

Sagaria, Sabato D.; Derks, Peter L.

In an effort to understand why pictures are used to supplement learning material, a study explored (1) the role of humor in recall, and (2) whether the effects of humor are independent of the individual's ability level. Subjects--students from either the high SAT (approximate average of 1200 points) population (HS), or the low SAT (approximate…

Providing Comprehensive Educational Opportunity to Low Income Students. Part 4: What Are the Social and Economic Returns?

ERIC Educational Resources Information Center

Belfield, Clive; Hollands, Fiona; Levin, Henry

2011-01-01

Approximately half of all New York City public school students who live in families with incomes less than 185% of the federal poverty level (FPL) do not graduate from high school. These dropouts are much less likely to achieve economic self-sufficiency in adulthood. This creates both a fiscal and social burden. Rothstein, Wilder and Allgood…

The Early School Leavers: Initial Survey. Report and Summary Report. Youth Transition into the Labour Market.

ERIC Educational Resources Information Center

Spain, William H.; Sharpe, Dennis B.

The study of Youth Transition into the Labour Market (YTLM) began several years ago in the spring of 1987. The project consists of two parallel yet interrelated studies, one focusing on the full cohort of approximately 9000 Level III high school students in Newfoundland and Labrador at the end of the 1988-89 school year, and a second, which…

Gamma Radiation Sterilization Reduces the High-cycle Fatigue Life of Allograft Bone.

PubMed

Islam, Anowarul; Chapin, Katherine; Moore, Emily; Ford, Joel; Rimnac, Clare; Akkus, Ozan

2016-03-01

Sterilization by gamma radiation impairs the mechanical properties of bone allografts. Previous work related to radiation-induced embrittlement of bone tissue has been limited mostly to monotonic testing which does not necessarily predict the high-cycle fatigue life of allografts in vivo. We designed a custom rotating-bending fatigue device to answer the following questions: (1) Does gamma radiation sterilization affect the high-cycle fatigue behavior of cortical bone; and (2) how does the fatigue life change with cyclic stress level? The high-cycle fatigue behavior of human cortical bone specimens was examined at stress levels related to physiologic levels using a custom-designed rotating-bending fatigue device. Test specimens were distributed among two treatment groups (n = 6/group); control and irradiated. Samples were tested until failure at stress levels of 25, 35, and 45 MPa. At 25 MPa, 83% of control samples survived 30 million cycles (run-out) whereas 83% of irradiated samples survived only 0.5 million cycles. At 35 MPa, irradiated samples showed an approximately 19-fold reduction in fatigue life compared with control samples (12.2 × 10(6) ± 12.3 × 10(6) versus 6.38 × 10(5) ± 6.81 × 10(5); p = 0.046), and in the case of 45 MPa, this reduction was approximately 17.5-fold (7.31 × 10(5) ± 6.39 × 10(5) versus 4.17 × 10(4) ± 1.91 × 10(4); p = 0.025). Equations to estimate high-cycle fatigue life of irradiated and control cortical bone allograft at a certain stress level were derived. Gamma radiation sterilization severely impairs the high cycle fatigue life of structural allograft bone tissues, more so than the decline that has been reported for monotonic mechanical properties. Therefore, clinicians need to be conservative in the expectation of the fatigue life of structural allograft bone tissues. Methods to preserve the fatigue strength of nonirradiated allograft bone tissue are needed. As opposed to what monotonic tests might suggest, the cyclic fatigue life of radiation-sterilized structural allografts is likely severely compromised relative to the nonirradiated condition and therefore should be taken into consideration. Methods to reduce the effect of irradiation or to recover structural allograft bone tissue fatigue strength are important to pursue.

The Hubble Space Telescope quasar absorption line key project. 6: Properties of the metal-rich systems

NASA Technical Reports Server (NTRS)

Bergeron, Jacqueline; Petitjean, Patrick; Sargent, W. L. W.; Bahcall, John N.; Boksenberg, Alec; Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Savage, Blair D.; Schneider, Donald P.

1994-01-01

We present an analysis of the properties of a sample of 18 metal-rich, low-redshift z(sub abs) much less than z(sub em) absorbers seen in low- and medium-resolution spectra obtained for the Quasar Absorption Line Key Project with the Hubble Space Telescope Faint Object Spectrograph (HST/FOS). For most of the C IV and Lyman-limit systems, observations in the optical wavelength range of the expected associated Mg II absorption are available. As at high redshift (z approximately 2), there are two subclasses of absorbers which are characterized by the presence or absence of MG II absorption. However, some low-redshift Mg II and Fe absorptions originate from regions optically thin to UV ionizing photons and thus, at low redshift, the low-ionization systems do not always trace high opacities, as is the case at high redshift. This implies that the mean ionization state of metal-rich, optically thin absorbing clouds falls with decreasing redshift, which is consistent with the hypothesis that the gas is photoionized by the metagalactic UV background radiation field. Two main constraints are derived from the analysis of the Lyman-limit sample, assuming photoionization models are valid. First, a low opacity to ionizing photons (tau(sub LL) approximately less than 1), as observed for several Mg II-Fe II systems at z approximately 0.5, sets limits on the ionization level of hydrogen, thus on the total hydrogen column density and the heavy element abundances, (Z/H) approximately -0.5 to -0.3. Second, the dimensions of individual Mg II clouds are smaller than at high redshift by a factor 3-10. At z approximately greater than 0.6, the O VI absorption doublet is detected in four of the five z(sub abs) much less than z(sub em) systems for which the O VI wavelength range has been observed, whereas the associated N V doublet is detected in only two cases. This suggests that the presence of a high-ionization O VI phase is a general property of z approximately 0.6-1 absorption systems, as is also probably the case at high redshift. These O VI absorbers can be ionized by the UV metagalactic field if their density is low, nH approximately less than 3 x 10(exp -4)/cc. The O VI phase would then be a homogeneous region of large extent, r approximately greater than 50 kpc. A detailed photoionization model of the z(sub abs) = 0.791 absorber toward PKS 2145+06 confirms the properties derived from the Mg II, C IV, O VI, and Lyman-limit samples. The galaxy causing this extensive metal-line absorption system has been identified, and its possible contribution to the UV ionizing flux does not substantially modify the value of the derived parameters. The heavy element abundances are about half the solar values. The O VI region has a density about 20 times lower than the Mg II clouds and a size of approximately 70 kpc. Alternatively, the high-ionization phase could be collisionally ionized and trace gas associated with a possible group of galaxies at the absorber redshift.

VERITAS Upper Limit on the Very High Energy Emission from the Radio Galaxy NGC 1275

DOE PAGES

Acciari, V. A.; Aliu, E.; Arlen, T.; ...

2009-11-16

We report the recent detection by the Fermi γ-ray space telescope of high-energy γ-rays from the radio galaxy NGC 1275 that makes the observation of the very high energy (VHE: E>100 GeV) part of its broadband spectrum particularly interesting, especially for the understanding of active galactic nuclei with misaligned multi-structured jets. The radio galaxy NGC 1275 was recently observed by VERITAS at energies above 100 GeV for about 8 hr. No VHE γ-ray emission was detected by VERITAS from NGC 1275. Finally, a 99% confidence level upper limit of 2.1% of the Crab Nebula flux level is obtained at themore » decorrelation energy of approximately 340 GeV, corresponding to 19% of the power-law extrapolation of the Fermi Large Area Telescope result.« less

Demonstration of Cost-Effective, High-Performance Computing at Performance and Reliability Levels Equivalent to a 1994 Vector Supercomputer

NASA Technical Reports Server (NTRS)

Babrauckas, Theresa

2000-01-01

The Affordable High Performance Computing (AHPC) project demonstrated that high-performance computing based on a distributed network of computer workstations is a cost-effective alternative to vector supercomputers for running CPU and memory intensive design and analysis tools. The AHPC project created an integrated system called a Network Supercomputer. By connecting computer work-stations through a network and utilizing the workstations when they are idle, the resulting distributed-workstation environment has the same performance and reliability levels as the Cray C90 vector Supercomputer at less than 25 percent of the C90 cost. In fact, the cost comparison between a Cray C90 Supercomputer and Sun workstations showed that the number of distributed networked workstations equivalent to a C90 costs approximately 8 percent of the C90.

World's mountains over 5 miles above sea level as seen from the Apollo 7

NASA Image and Video Library

1968-10-15

AS7-07-1748 (15 Oct. 1968) --- The world's dozen peaks which reach a height of greater than five miles above sea level are seen in this photograph from the Apollo 7 spacecraft at an altitude of approximately 130 nautical miles. The 29,028 ft. high Mount Everest is at lower center. On the central horizon can be seen the 28,250 ft. high Mount Godwin-Austen (K-2) some 800 miles northwest of Mount Everest. In the lower right, Mount Kanchenjunga rises 28,208 ft. to separate Nepal from Sikkim. The snow line on the peaks was at 17,500 ft. In the upper right the lake-studded highlands of Tibet are visible.

Two-photon excitation cross-section in light and intermediate atoms

NASA Technical Reports Server (NTRS)

Omidvar, K.

1980-01-01

The method of explicit summation over the intermediate states is used along with LS coupling to derive an expression for two-photon absorption cross section in light and intermediate atoms in terms of integrals over radial wave functions. Two selection rules, one exact and one approximate, are also derived. In evaluating the radial integrals, for low-lying levels, the Hartree-Fock wave functions, and for high-lying levels, hydrogenic wave functions obtained by the quantum defect method are used. A relationship between the cross section and the oscillator strengths is derived. Cross sections due to selected transitions in nitrogen, oxygen, and chlorine are given. The expression for the cross section is useful in calculating the two-photon absorption in light and intermediate atoms.

Multilevel cascade voltage source inverter with seperate DC sources

DOEpatents

Peng, Fang Zheng; Lai, Jih-Sheng

1997-01-01

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

Multilevel cascade voltage source inverter with seperate DC sources

DOEpatents

Peng, Fang Zheng; Lai, Jih-Sheng

2002-01-01

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

Multilevel cascade voltage source inverter with seperate DC sources

DOEpatents

Peng, Fang Zheng; Lai, Jih-Sheng

2001-04-03

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

Multilevel cascade voltage source inverter with separate DC sources

DOEpatents

Peng, F.Z.; Lai, J.S.

1997-06-24

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

A novel and sensitive radioreceptor assay for serum melatonin levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tenn, C.; Niles, L.

A simple and sensitive radioreceptor assay (RRA) has been developed to measure melatonin levels in serum. The assay is based on competition between 2-({sup 125}I)iodomelatonin (({sup 125}I)MEL) and melatonin for binding to high-affinity binding sites in chick forebrain. To measure the amount of melatonin present in a serum sample, it was extracted with dichloromethane and added to the assay medium. The percentage inhibition of radioligand binding in the presence of the extracted serum was determined and compared to the percent displacement by known amounts of melatonin in a standard curve. There was little or no cross-reactivity with other structurally relatedmore » compounds. The sensitivity of the assay is {approximately}1.5pg/0.15 mL and the intra- and inter-assay variations are approximately 8%. Since the RRA results are comparable to that of an established radioimmunoassay (RIA), it provides a sensitive and rapid alternative to the more time consuming RIA.« less

Inactivation of Mycobacterium paratuberculosis by Pulsed Electric Fields

PubMed Central

Rowan, Neil J.; MacGregor, Scott J.; Anderson, John G.; Cameron, Douglas; Farish, Owen

2001-01-01

The influence of treatment temperature and pulsed electric fields (PEF) on the viability of Mycobacterium paratuberculosis cells suspended in 0.1% (wt/vol) peptone water and in sterilized cow's milk was assessed by direct viable counts and by transmission electron microscopy (TEM). PEF treatment at 50°C (2,500 pulses at 30 kV/cm) reduced the level of viable M. paratuberculosis cells by approximately 5.3 and 5.9 log10 CFU/ml in 0.1% peptone water and in cow's milk, respectively, while PEF treatment of M. paratuberculosis at lower temperatures resulted in less lethality. Heating alone at 50°C for 25 min or at 72°C for 25 s (extended high-temperature, short-time pasteurization) resulted in reductions of M. paratuberculosis of approximately 0.01 and 2.4 log10 CFU/ml, respectively. TEM studies revealed that exposure to PEF treatment resulted in substantial damage at the cellular level to M. paratuberculosis. PMID:11375202

Differences in Use of Government Subsidised Mental Health Services by Men and Women with Psychological Distress: A Study of 229,628 Australians Aged 45 Years and Over.

PubMed

Dolja-Gore, Xenia; Loxton, Deborah; D'Este, Catherine; Blyth, Fiona; Byles, Julie

2018-04-17

This study examined factors associated with use of government subsidised mental health services by 229,628 men and women from the Sax Institute's 45 and Up Study. Logistical regression models assessed use of mental health services by gender and according to level of psychological distress. Approximately equal proportion of men and women had high psychological distress scores (approximately 7%) but only 7% of these men and 11% of these women used services. Use was associated with predisposing (younger age and higher education), enabling (private health insurance) and need factors (higher psychological distress scores). Associations were similar for men and women except urban area of residence, separated/divorced marital status, and smoking were associated with service use for women but not men. Results suggest some inequity in the use of services by those with higher levels of need and further efforts may be required to reach people with higher need but lower service use.

Browns Ferry Nuclear Plant Unit 2: Control rod drive scram discharge headers decontamination effort

DOE Office of Scientific and Technical Information (OSTI.GOV)

Traynor, J.C.

1983-08-01

The control rod drive (CRD) scram discharge headers were decontaminated during the Browns Ferry unit 2, cycle 4 refueling outage (August 2-5, 1982). Hydrolasing (high-pressure water blasting) was used as the method of decontamination to remove fixed and loose radioactive contaminants from the headers. It was found that hydrolasing of the west scram discharge headers resulted in approximate maximum and average decontamination factors (DFs) on contact of 13 and 5, respectively. For the east scram discharge headers, hydrolasing resulted in a maximum and average DF on contact of approximately 3. The maximum and average DFs on contact for the individualmore » headers ranged from 1 to 33 and 1 to 10, respectively, while the walkway (head-level) DFs were in the range of 3 to 4. Higher DFs were impeded by inadequate drainage and backwashing of fluid. This led to increased radiation levels in some areas and recontamination of adjacent headers.« less

Optimum Climb to Cruise Noise Trajectories for the High Speed Civil Transport

NASA Technical Reports Server (NTRS)

Berton, Jeffrey J.

2003-01-01

By entraining large quantities of ambient air into advanced ejector nozzles, the jet noise of the proposed High Speed Civil Transport (HSCT) is expected to be reduced to levels acceptable for airport-vicinity noise certification. Away from the airport, however, this entrained air is shut off and the engines are powered up from their cutback levels to provide better thrust for the climb to cruise altitude. Unsuppressed jet noise levels propagating to the ground far from the airport are expected to be high. Complicating this problem is the HSCT's relative noise level with respect to the subsonic commercial fleet of 2010, which is expected to be much quieter than it is today after the retirement of older, louder, domestic stage II aircraft by the year 2000. In this study, the classic energy state approximation theory is extended to calculate trajectories that minimize the climb to cruise noise of the HSCT. The optimizer dynamically chooses the optimal altitude velocity trajectory, the engine power setting, and whether the ejector should be stowed or deployed with respect to practical aircraft climb constraints and noise limits.

Digital transillumination in caries detection versus radiographic and clinical methods: an in-vivo study

PubMed Central

Lara-Capi, Cynthia; Lingström, Peter; Lai, Gianfranco; Cocco, Fabio; Simark-Mattsson, Charlotte; Campus, Guglielmo

2017-01-01

Objectives: This article aimed to evaluate: (a) the agreement between a near-infrared light transillumination device and clinical and radiographic examinations in caries lesion detection and (b) the reliability of images captured by the transillumination device. Methods: Two calibrated examiners evaluated the caries status in premolars and molars on 52 randomly selected subjects by comparing the transillumination device with a clinical examination for the occlusal surfaces and by comparing the transillumination device with a radiographic examination (bitewing radiographs) for the approximal surfaces. Forty-eight trained dental hygienists evaluated and reevaluated 30 randomly selected images 1-month later. Results: A high concordance between transillumination method and clinical examination (kappa = 0.99) was detected for occlusal caries lesions, while for approximal surfaces, the transillumination device identified a higher number of lesions with respect to bitewing (kappa = 0.91). At the dentinal level, the two methods identified the same number of caries lesions (kappa = 1), whereas more approximal lesions were recorded using the transillumination device in the enamel (kappa = 0.24). The intraexaminer reliability was substantial/almost perfect in 59.4% of the participants. Conclusions: The transillumination method showed a high concordance compared with traditional methods (clinical examination and bitewing radiographs). Caries detection reliability using the transillumination device images showed a high intraexaminer agreement. Transillumination showed to be a reliable method and as effective as traditional methods in caries detection. PMID:28191797

High-Level Ab Initio Calculations of Intermolecular Interactions: Heavy Main-Group Element π-Interactions.

PubMed

Krasowska, Małgorzata; Schneider, Wolfgang B; Mehring, Michael; Auer, Alexander A

2018-05-02

This work reports high-level ab initio calculations and a detailed analysis on the nature of intermolecular interactions of heavy main-group element compounds and π systems. For this purpose we have chosen a set of benchmark molecules of the form MR 3 , in which M=As, Sb, or Bi, and R=CH 3 , OCH 3 , or Cl. Several methods for the description of weak intermolecular interactions are benchmarked including DFT-D, DFT-SAPT, MP2, and high-level coupled cluster methods in the DLPNO-CCSD(T) approximation. Using local energy decomposition (LED) and an analysis of the electron density, details of the nature of this interaction are unraveled. The results yield insight into the nature of dispersion and donor-acceptor interactions in this type of system, including systematic trends in the periodic table, and also provide a benchmark for dispersion interactions in heavy main-group element compounds. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Apolipoprotein A-V: a potential modulator of plasma triglyceride levels in Turks.

PubMed

Hodoglugil, Ugur; Tanyolaç, Sinan; Williamson, David W; Huang, Yadong; Mahley, Robert W

2006-01-01

The apolipoprotein A-V gene (APOA5) plays an important role in determining plasma triglyceride levels. We studied the effects of APOA5 polymorphisms on plasma triglyceride levels in Turks, a population with low levels of HDL cholesterol and a high prevalence of coronary artery disease. We found 15 polymorphisms, three of which were novel. Seven haplotype-tagging single nucleotide polymorphisms (SNPs) were chosen and genotyped in approximately 3,000 subjects. The rare alleles of the -1464T>C, -1131T>C, S19W, and 1259T>C SNPs were significantly associated with increased triglyceride levels (19-86 mg/dl; P < 0.05) and had clear gene-dose effects. Haplotype analysis of the nine common APOA5 haplotypes revealed significant effects on triglyceride levels (P < 0.001). Detailed analysis of haplotypes clearly showed that the -1464T>C polymorphism had no effect by itself but was a marker for the -1131T>C, S19W, and 1259T>C polymorphisms. The -1131T>C and 1259T>C polymorphisms were in a strong but incomplete linkage disequilibrium and appeared to have independent effects. Thus, the APOA5 -1131T>C, S19W, and 1259T>C rare alleles were associated with significant increases in plasma triglyceride levels. At least one of these alleles was present in approximately 40% of the Turks. Similar associations were observed for -1131T>C and S19W in white Americans living in San Francisco, California.

Approximate number sense correlates with math performance in gifted adolescents.

PubMed

Wang, Jinjing Jenny; Halberda, Justin; Feigenson, Lisa

2017-05-01

Nonhuman animals, human infants, and human adults all share an Approximate Number System (ANS) that allows them to imprecisely represent number without counting. Among humans, people differ in the precision of their ANS representations, and these individual differences have been shown to correlate with symbolic mathematics performance in both children and adults. For example, children with specific math impairment (dyscalculia) have notably poor ANS precision. However, it remains unknown whether ANS precision contributes to individual differences only in populations of people with lower or average mathematical abilities, or whether this link also is present in people who excel in math. Here we tested non-symbolic numerical approximation in 13- to 16-year old gifted children enrolled in a program for talented adolescents (the Center for Talented Youth). We found that in this high achieving population, ANS precision significantly correlated with performance on the symbolic math portion of two common standardized tests (SAT and ACT) that typically are administered to much older students. This relationship was robust even when controlling for age, verbal performance, and reaction times in the approximate number task. These results suggest that the Approximate Number System is linked to symbolic math performance even at the top levels of math performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Performance evaluation of an in situ nitrous acid measurement system and continuous measurement of nitrous acid in an indoor environment.

PubMed

Park, Seung Shik; Cho, Sung Yong

2010-12-01

Nitrous acid (HONO) may cause adverse effects to mucous membranes and lung function when people are exposed to higher HONO concentrations than those present in typical indoor residential environments. Therefore, determination of HONO concentration in indoor environments is required to investigate occurrences of high HONO levels. In this work, a high-time-resolution measurement system was utilized to better understand the levels and dynamic behavior of HONO in an indoor environment. The performance of the in situ HONO analyzer applied to this work was evaluated using a 12-hr integrated annular denuder technique under ambient conditions. Both methods for the measurements of HONO were in good agreement, with a regression slope of 0.84, an intercept of 0.09, and correlation coefficient (r2) of 0.67. Indoor HONO and nitrogen oxide concentrations were also observed for approximately 5 days in winter in the living room of an apartment that had a gas range for cooking in the kitchen. Investigation of the relationships among nitric oxide (NO), nitrite (NO2), and HONO concentrations suggests that HONO production during combustion could be the result of direct emission, whereas the heterogeneous NO2 chemistry during the background period and after combustion was the possible pathway of HONO production. Controlled combustion experiments, performed at a burning rate of 50% valve setting, show peak HONO concentrations during the unvented combustion to be approximately 8-10 times higher than background levels depending on the time of day. At a burning rate setting of 50%, the peak concentration of HONO during unvented combustion was found to be 33-37% higher than those from "weak" (airflow = 340 m3/hr) and "strong" (airflow = 540 m3/hr) vented combustions. The decay rate of the HONO concentrations for the unvented combustion conditions was approximately 2-fold higher in the daytime than in the nighttime and significantly less than those of NO and NO2.

Utilising shade to optimize UV exposure for vitamin D

NASA Astrophysics Data System (ADS)

Turnbull, D. J.; Parisi, A. V.

2008-01-01

Numerous studies have stated that humans need to utilise full sun radiation, at certain times of the day, to assist the body in synthesising the required levels of vitamin D3. The time needed to be spent in the full sun depends on a number of factors, for example, age, skin type, latitude, solar zenith angle. Current Australian guidelines suggest exposure to approximately 1/6 to 1/3 of a minimum erythemal dose (MED), depending on age, would be appropriate to provide adequate vitamin D3 levels. The aim of the study was to determine the exposure times to diffuse solar UV to receive exposures of 1/6 and 1/3 MED for a changing solar zenith angle in order to assess the possible role that diffuse UV (scattered radiation) may play in vitamin D3 effective UV exposures (UVD3). Diffuse and global erythemal UV measurements were conducted at five minute intervals over a twelve month period for a solar zenith angle range of 4° to 80° at a latitude of 27.6° S. For diffuse UV exposures of 1/6 and 1/3 MED, solar zenith angles smaller than 60° and 50° respectively can be utilised for exposure times of less than 10 min. Spectral measurements showed that, for a solar zenith angle of 40°, the UVA (315-400 nm) in the diffuse component of the solar UV is reduced by approximately 62% compared to the UVA in the global UV, whereas UVD3 wavelengths are only reduced by approximately 43%. At certain latitudes, diffuse UV under shade may play an important role in providing the human body with adequate levels of UVD3 (290-330 nm) radiation without experiencing the high levels of damaging UVA observed in full sun.

Resummation of divergent perturbation series: Application to the vibrational states of H{sub 2}CO molecule

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duchko, A. N.; V.E. Zuev Institute of Atmospheric Optics, Tomsk; Bykov, A. D., E-mail: adbykov@rambler.ru

2015-10-21

Large-order Rayleigh–Schrödinger perturbation theory (RSPT) is applied to the calculation of anharmonic vibrational energy levels of H{sub 2}CO molecule. We use the model of harmonic oscillators perturbed by anharmonic terms of potential energy. Since the perturbation series typically diverge due to strong couplings, we apply the algebraic approximation technique because of its effectiveness shown earlier by Goodson and Sergeev [J. Chem. Phys. 110, 8205 (1999); ibid. 124, 094111 (2006)] and in our previous articles [A. D. Bykov et al. Opt. Spectrosc. 114, 396 (2013); ibid. 116, 598 (2014)]. To facilitate the resummation of terms contributing to perturbed states, when resonancemore » mixing between states is especially strong and perturbation series diverge very quick, we used repartition of the Hamiltonian by shifting the normal mode frequencies. Energy levels obtained by algebraic approximants were compared with the results of variational calculation. It was found that for low energy states (up to ∼5000 cm{sup −1}), algebraic approximants gave accurate values of energy levels, which were in excellent agreement with the variational method. For highly excited states, strong and multiple resonances complicate series resummation, but a suitable change of normal mode frequencies allows one to reduce the resonance mixing and to get accurate energy levels. The theoretical background of the problem of RSPT series divergence is discussed along with its numerical analysis. For these purposes, the vibrational energy is considered as a function of a complex perturbation parameter. Layout and classification of its singularities allow us to model the asymptotic behavior of the perturbation series and prove the robustness of the algorithm.« less

Lactic acid bacteria affect serum cholesterol levels, harmful fecal enzyme activity, and fecal water content.

PubMed

Lee, Do Kyung; Jang, Seok; Baek, Eun Hye; Kim, Mi Jin; Lee, Kyung Soon; Shin, Hea Soon; Chung, Myung Jun; Kim, Jin Eung; Lee, Kang Oh; Ha, Nam Joo

2009-06-11

Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as lower cholesterol. Although present in many foods, most trials have been in spreads or dairy products. Here we tested whether Bifidobacteria isolates could lower cholesterol, inhibit harmful enzyme activities, and control fecal water content. In vitro culture experiments were performed to evaluate the ability of Bifidobacterium spp. isolated from healthy Koreans (20 approximately 30 years old) to reduce cholesterol-levels in MRS broth containing polyoxyethanylcholesterol sebacate. Animal experiments were performed to investigate the effects on lowering cholesterol, inhibiting harmful enzyme activities, and controlling fecal water content. For animal studies, 0.2 ml of the selected strain cultures (108 approximately 109 CFU/ml) were orally administered to SD rats (fed a high-cholesterol diet) every day for 2 weeks. B. longum SPM1207 reduced serum total cholesterol and LDL levels significantly (p < 0.05), and slightly increased serum HDL. B. longum SPM1207 also increased fecal LAB levels and fecal water content, and reduced body weight and harmful intestinal enzyme activities. Daily consumption of B. longum SPM1207 can help in managing mild to moderate hypercholesterolemia, with potential to improve human health by helping to prevent colon cancer and constipation.

Technical and clinical aspects of cortisol as a biochemical marker of chronic stress.

PubMed

Lee, Do Yup; Kim, Eosu; Choi, Man Ho

2015-04-01

Stress is now recognized as a universal premorbid factor associated with many risk factors of various chronic diseases. Acute stress may induce an individual's adaptive response to environmental demands. However, chronic, excessive stress causes cumulative negative impacts on health outcomes through "allostatic load". Thus, monitoring the quantified levels of long-term stress mediators would provide a timely opportunity for prevention or earlier intervention of stress-related chronic illnesses. Although either acute or chronic stress could be quantified through measurement of changes in physiological parameters such as heart rate, blood pressure, and levels of various metabolic hormones, it is still elusive to interpret whether the changes in circulating levels of stress mediators such as cortisol can reflect the acute, chronic, or diurnal variations. Both serum and salivary cortisol levels reveal acute changes at a single point in time, but the overall long-term systemic cortisol exposure is difficult to evaluate due to circadian variations and its protein-binding capacity. Scalp hair has a fairy predictable growth rate of approximately 1 cm/month, and the most 1 cm segment approximates the last month's cortisol production as the mean value. The analysis of cortisol in hair is a highly promising technique for the retrospective assessment of chronic stress.

Quantification of nerve agent VX-butyrylcholinesterase adduct biomarker from an accidental exposure.

PubMed

Solano, Maria I; Thomas, Jerry D; Taylor, James T; McGuire, Jeffrey M; Jakubowski, Edward M; Thomson, Sandra A; Maggio, Vincent L; Holland, Kerry E; Smith, J Richard; Capacio, Benedict; Woolfitt, Adrian R; Ashley, David L; Barr, John R

2008-01-01

The lack of data in the open literature on human exposure to the nerve agent O-ethyl-S-(2-diisopropylaminoethyl) methylphosphonothioate (VX) gives a special relevance to the data presented in this study in which we report the quantification of VX-butyrylcholinesterase adduct from a relatively low-level accidental human exposure. The samples were analyzed by gas chromatography-high resolution mass spectrometry using the fluoride ion regeneration method for the quantification of multiple nerve agents including VX. Six human plasma samples from the same individual were collected after the patient had been treated once with oxime immediately after exhibiting signs of exposure. Detection limits of approximately 5.5 pg/mL plasma were achieved for the G-analogue of VX (G-VX). Levels of the G-VX ranged from 81.4 pg/mL on the first day after the exposure to 6.9 pg/mL in the sample taken 27 days after the exposure. Based on the reported concentration of human butyrylcholinesterase in plasma of approximately 80 nM, it can be calculated that inhibition levels of >or= 0.05% of BuChE can be accurately quantified. These data further indicate that the fluoride ion regeneration method is a potentially powerful tool that can be used to assess low-level exposure to VX.

Larval development assays reveal the presence of sub-populations showing high- and low-level resistance in a monepantel (Zolvix®)-resistant isolate of Haemonchus contortus.

PubMed

Raza, Ali; Lamb, Jane; Chambers, Michael; Hunt, Peter W; Kotze, Andrew C

2016-04-15

Resistance to the amino-acetonitrile derivative monepantel has been reported in several species of gastrointestinal nematodes over recent years. We were interested in the use of in vitro assays with free-living worm life-stages to detect resistance to this drug. We therefore used larval development and larval migration assays to examine dose response relationships for the drug against two susceptible and one resistant isolate of Haemonchus contortus. The resistant isolate was established by laboratory propagation of the survivors of a field treatment with Zolvix(®) that had originally resulted in a drug efficacy of over 99%. Drug efficacy against this field-derived laboratory-propagated resistant isolate in vivo was approximately 15%. The larval development assay proved able to discriminate between the susceptible and resistant isolates, with larvae of the resistant isolate showing an ability to develop at higher drug concentrations than the two susceptible isolates. The resistant isolate showed the presence of two distinct subpopulations, separated by a plateau in the dose-response curve. Sub-population 1 (approximately 40% of the total population) showed a low level of resistance with an IC50 increased approximately 7-fold compared to the baseline susceptible isolate, while sub-population 2 (the remaining 60% of the total population) showed an IC50 increased over 1000-fold compared to the baseline susceptible isolate. This level of resistance is unusually high for any gastrointestinal nematode species in drug dose-response in vitro assays. In contrast, the migration assay could not discriminate between the three isolates, with migration not reduced to zero at any of the drug concentrations tested. This study demonstrates that a larval development assay is able to detect resistance to monepantel in H. contortus, and that resistance can exist in two distinct forms. This suggests that at least two separate monepantel resistance mechanisms are acting within the worm isolate studied here, with one or more mechanisms conferring a much higher level of resistance than the other(s). Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Electron momentum density and band structure calculations of α- and β-GeTe

NASA Astrophysics Data System (ADS)

Vadkhiya, Laxman; Arora, Gunjan; Rathor, Ashish; Ahuja, B. L.

2011-12-01

We have measured isotropic experimental Compton profile of α-GeTe by employing high energy (662 keV) γ-radiation from a 137Cs isotope. To compare our experiment, we have also computed energy bands, density of states, electron momentum densities and Compton profiles of α- and β-phases of GeTe using the linear combination of atomic orbitals method. The electron momentum density is found to play a major role in understanding the topology of bands in the vicinity of the Fermi level. It is seen that the density functional theory (DFT) with generalised gradient approximation is relatively in better agreement with the experiment than the local density approximation and hybrid Hartree-Fock/DFT.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Zheming; Yoshii, Kazutomo; Finkel, Hal

Open Computing Language (OpenCL) is a high-level language that enables software programmers to explore Field Programmable Gate Arrays (FPGAs) for application acceleration. The Intel FPGA software development kit (SDK) for OpenCL allows a user to specify applications at a high level and explore the performance of low-level hardware acceleration. In this report, we present the FPGA performance and power consumption results of the single-precision floating-point vector add OpenCL kernel using the Intel FPGA SDK for OpenCL on the Nallatech 385A FPGA board. The board features an Arria 10 FPGA. We evaluate the FPGA implementations using the compute unit duplication andmore » kernel vectorization optimization techniques. On the Nallatech 385A FPGA board, the maximum compute kernel bandwidth we achieve is 25.8 GB/s, approximately 76% of the peak memory bandwidth. The power consumption of the FPGA device when running the kernels ranges from 29W to 42W.« less

Farfield inflight measurements of high-speed turboprop noise

NASA Technical Reports Server (NTRS)

Balombin, J. R.; Loeffler, I. J.

1983-01-01

A flight program was carried out to determine the variation of noise level with distance from a model high-speed propeller. Noise measurements were obtained at different distances from a SR-3 propeller mounted on a JetStar aircraft, with the test instrumentation mounted on a Learjet flown in formation. The propeller was operated at 0.8 m flight Mach number, 1.12 helical tip Mach number and at 0.7 flight Mach number, 1.0 helical tip Mach number. The instantaneous pressure from individual blades was observed to rise faster at the 0.8 flight speed, than at the 0.7 M flight speed. The measured levels appeared to decrease in good agreement with a 6 dB/doubling of distance decay, over the measurement range of approximately 16 m to 100 m distance. Further extrapolation, to the distances represented by a community, would suggest that the propagated levels during cruise would not cause a serious community annoyance.

Climate and lake-level history of the northern altiplano, Bolivia, as recorded in holocene sediments of the Rio Desaguadero

USGS Publications Warehouse

Baucom, P.C.; Rigsby, C.A.

1999-01-01

Strata exposed in terraces and modern cutbanks along the Rio Desaguadero contain a variety of lithofacies that were deposited in four distinct facie??s associations. These facie??s associations document a history of aggradation and downcutting that is linked to Holocene climate change on the Altiplano. Braided-stream, meandering-stream, deltaic and shoreline, and lacustrine sediments preserved in multi-level terraces in the northern Rio Desaguadero valley record two high-water intervals: one between 4500 and 3900 yr BP and another between 2000 and 2200 yr BP. These wet periods were interrupted by three periods of fluvial downcutting, centered at approximately 4000 yr BP, 3600 yr BP, and after 2000 yr BP. Braided-river sediments preserved in a single terrace level in the southern Rio Desaguadero valley record a history of nearly continuous fluvial sedimentation from at least 7000 yr BP until approximately 3200 yr BP that was followed by a single episode (post-3210 yr BP) of downcutting and lateral migration. The deposition and subsequent fluvial downcutting of the northern strata was controlled by changes in effective moisture that can be correlated to Holocene water-level fluctuations of Lake Titicaca. The deposition and dissection of braided-stream sediments to the south are more likely controlled by a combination of base-level change and sediment input from the Rio Mauri. Copyright ??1999, SEPM (Society for Sedimentar)- Geology).

High-throughput sequence analysis of Ciona intestinalis SL trans-spliced mRNAs: alternative expression modes and gene function correlates.

PubMed

Matsumoto, Jun; Dewar, Ken; Wasserscheid, Jessica; Wiley, Graham B; Macmil, Simone L; Roe, Bruce A; Zeller, Robert W; Satou, Yutaka; Hastings, Kenneth E M

2010-05-01

Pre-mRNA 5' spliced-leader (SL) trans-splicing occurs in some metazoan groups but not in others. Genome-wide characterization of the trans-spliced mRNA subpopulation has not yet been reported for any metazoan. We carried out a high-throughput analysis of the SL trans-spliced mRNA population of the ascidian tunicate Ciona intestinalis by 454 Life Sciences (Roche) pyrosequencing of SL-PCR-amplified random-primed reverse transcripts of tailbud embryo RNA. We obtained approximately 250,000 high-quality reads corresponding to 8790 genes, approximately 58% of the Ciona total gene number. The great depth of this data revealed new aspects of trans-splicing, including the existence of a significant class of "infrequently trans-spliced" genes, accounting for approximately 28% of represented genes, that generate largely non-trans-spliced mRNAs, but also produce trans-spliced mRNAs, in part through alternative promoter use. Thus, the conventional qualitative dichotomy of trans-spliced versus non-trans-spliced genes should be supplanted by a more accurate quantitative view recognizing frequently and infrequently trans-spliced gene categories. Our data include reads representing approximately 80% of Ciona frequently trans-spliced genes. Our analysis also revealed significant use of closely spaced alternative trans-splice acceptor sites which further underscores the mechanistic similarity of cis- and trans-splicing and indicates that the prevalence of +/-3-nt alternative splicing events at tandem acceptor sites, NAGNAG, is driven by spliceosomal mechanisms, and not nonsense-mediated decay, or selection at the protein level. The breadth of gene representation data enabled us to find new correlations between trans-splicing status and gene function, namely the overrepresentation in the frequently trans-spliced gene class of genes associated with plasma/endomembrane system, Ca(2+) homeostasis, and actin cytoskeleton.

Thermal Conductivity and Erosion Durability of Composite Two-Phase Air Plasma Sprayed Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Schmitt, Michael P.; Rai, Amarendra K.; Zhu, Dongming; Dorfman, Mitchell R.; Wolfe, Douglas E.

2015-01-01

To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7 wt% yttria stabilized zirconia (7YSZ), approximately 1200 C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t' Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by approximately 13 and approximately 25%, respectively. The 40 wt% t' Low-k composite (40 wt% t' Low-k - 60 wt% cubic Low-k) showed a approximately 22% reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal in the composite coating. It was observed that a mere 20 wt% t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37%. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability.

Adolescent pathways to adulthood drinking: sport activity involvement is not necessarily risky or protective

PubMed Central

Peck, Stephen C.; Vida, Mina; Eccles, Jacquelynne S.

2015-01-01

Aims Use pattern-centered methods to examine how adolescents’ alcohol use and sports activities are related both to childhood sport and problem behavior and to heavy drinking in early adulthood. Design The data used in this study come from four waves of the Michigan Study of Adolescent Life Transitions (MSALT) that began in 1983, when participants were approximately age 12, and continued into early adulthood, when participants were approximately age 28. Participants Sixty per cent of the approximately 1000 MSALT youth living in south-eastern Michigan were females and 97% were European American. Approximately 28% of one or both parents held at least a college degree, and 45% held a high school diploma or lower. Findings Pattern-centered analyses revealed that the relation between adolescent sport activity and age 28 heavy alcohol use obtained primarily for sport participants who were also using more than the average amount of alcohol and other drugs at age 18. Similarly, children who were characterized by relatively high levels of sport participation, aggression and other problem behavior at age 12 were more likely than expected by chance to become sport participants who used more than the average amount of alcohol and other drugs at age 18. Conclusions The results indicate that childhood problem behavior and adolescent sport participation can, but do not necessarily, presage heavy drinking in adulthood and that pattern-centered analytical techniques are useful for revealing such theoretically generated predictions. PMID:18426541

Point defects in ZnO: an approach from first principles

PubMed Central

Oba, Fumiyasu; Choi, Minseok; Togo, Atsushi; Tanaka, Isao

2011-01-01

Recent first-principles studies of point defects in ZnO are reviewed with a focus on native defects. Key properties of defects, such as formation energies, donor and acceptor levels, optical transition energies, migration energies and atomic and electronic structure, have been evaluated using various approaches including the local density approximation (LDA) and generalized gradient approximation (GGA) to DFT, LDA+U/GGA+U, hybrid Hartree–Fock density functionals, sX and GW approximation. Results significantly depend on the approximation to exchange correlation, the simulation models for defects and the post-processes to correct shortcomings of the approximation and models. The choice of a proper approach is, therefore, crucial for reliable theoretical predictions. First-principles studies have provided an insight into the energetics and atomic and electronic structures of native point defects and impurities and defect-induced properties of ZnO. Native defects that are relevant to the n-type conductivity and the non-stoichiometry toward the O-deficient side in reduced ZnO have been debated. It is suggested that the O vacancy is responsible for the non-stoichiometry because of its low formation energy under O-poor chemical potential conditions. However, the O vacancy is a very deep donor and cannot be a major source of carrier electrons. The Zn interstitial and anti-site are shallow donors, but these defects are unlikely to form at a high concentration in n-type ZnO under thermal equilibrium. Therefore, the n-type conductivity is attributed to other sources such as residual impurities including H impurities with several atomic configurations, a metastable shallow donor state of the O vacancy, and defect complexes involving the Zn interstitial. Among the native acceptor-type defects, the Zn vacancy is dominant. It is a deep acceptor and cannot produce a high concentration of holes. The O interstitial and anti-site are high in formation energy and/or are electrically inactive and, hence, are unlikely to play essential roles in electrical properties. Overall defect energetics suggests a preference for the native donor-type defects over acceptor-type defects in ZnO. The O vacancy, Zn interstitial and Zn anti-site have very low formation energies when the Fermi level is low. Therefore, these defects are expected to be sources of a strong hole compensation in p-type ZnO. For the n-type doping, the compensation of carrier electrons by the native acceptor-type defects can be mostly suppressed when O-poor chemical potential conditions, i.e. low O partial pressure conditions, are chosen during crystal growth and/or doping. PMID:27877390

High-Dimensional Function Approximation With Neural Networks for Large Volumes of Data.

PubMed

Andras, Peter

2018-02-01

Approximation of high-dimensional functions is a challenge for neural networks due to the curse of dimensionality. Often the data for which the approximated function is defined resides on a low-dimensional manifold and in principle the approximation of the function over this manifold should improve the approximation performance. It has been show that projecting the data manifold into a lower dimensional space, followed by the neural network approximation of the function over this space, provides a more precise approximation of the function than the approximation of the function with neural networks in the original data space. However, if the data volume is very large, the projection into the low-dimensional space has to be based on a limited sample of the data. Here, we investigate the nature of the approximation error of neural networks trained over the projection space. We show that such neural networks should have better approximation performance than neural networks trained on high-dimensional data even if the projection is based on a relatively sparse sample of the data manifold. We also find that it is preferable to use a uniformly distributed sparse sample of the data for the purpose of the generation of the low-dimensional projection. We illustrate these results considering the practical neural network approximation of a set of functions defined on high-dimensional data including real world data as well.

Solution NMR investigation of the response of the lactose repressor core domain dimer to hydrostatic pressure.

PubMed

Fuglestad, Brian; Stetz, Matthew A; Belnavis, Zachary; Wand, A Joshua

2017-12-01

Previous investigations of the sensitivity of the lac repressor to high-hydrostatic pressure have led to varying conclusions. Here high-pressure solution NMR spectroscopy is used to provide an atomic level view of the pressure induced structural transition of the lactose repressor regulatory domain (LacI* RD) bound to the ligand IPTG. As the pressure is raised from ambient to 3kbar the native state of the protein is converted to a partially unfolded form. Estimates of rotational correlation times using transverse optimized relaxation indicates that a monomeric state is never reached and that the predominate form of the LacI* RD is dimeric throughout this pressure change. Spectral analysis suggests that the pressure-induced transition is localized and is associated with a volume change of approximately -115mlmol -1 and an average pressure dependent change in compressibility of approximately 30mlmol -1 kbar -1 . In addition, a subset of resonances emerge at high-pressures indicating the presence of a non-native but folded alternate state. Copyright © 2017 Elsevier B.V. All rights reserved.

Designing a robust activity recognition framework for health and exergaming using wearable sensors.

PubMed

Alshurafa, Nabil; Xu, Wenyao; Liu, Jason J; Huang, Ming-Chun; Mortazavi, Bobak; Roberts, Christian K; Sarrafzadeh, Majid

2014-09-01

Detecting human activity independent of intensity is essential in many applications, primarily in calculating metabolic equivalent rates and extracting human context awareness. Many classifiers that train on an activity at a subset of intensity levels fail to recognize the same activity at other intensity levels. This demonstrates weakness in the underlying classification method. Training a classifier for an activity at every intensity level is also not practical. In this paper, we tackle a novel intensity-independent activity recognition problem where the class labels exhibit large variability, the data are of high dimensionality, and clustering algorithms are necessary. We propose a new robust stochastic approximation framework for enhanced classification of such data. Experiments are reported using two clustering techniques, K-Means and Gaussian Mixture Models. The stochastic approximation algorithm consistently outperforms other well-known classification schemes which validate the use of our proposed clustered data representation. We verify the motivation of our framework in two applications that benefit from intensity-independent activity recognition. The first application shows how our framework can be used to enhance energy expenditure calculations. The second application is a novel exergaming environment aimed at using games to reward physical activity performed throughout the day, to encourage a healthy lifestyle.

Investigating sub-spine actin dynamics in rat hippocampal neurons with super-resolution optical imaging.

PubMed

Tatavarty, Vedakumar; Kim, Eun-Ji; Rodionov, Vladimir; Yu, Ji

2009-11-09

Morphological changes in dendritic spines represent an important mechanism for synaptic plasticity which is postulated to underlie the vital cognitive phenomena of learning and memory. These morphological changes are driven by the dynamic actin cytoskeleton that is present in dendritic spines. The study of actin dynamics in these spines traditionally has been hindered by the small size of the spine. In this study, we utilize a photo-activation localization microscopy (PALM)-based single-molecule tracking technique to analyze F-actin movements with approximately 30-nm resolution in cultured hippocampal neurons. We were able to observe the kinematic (physical motion of actin filaments, i.e., retrograde flow) and kinetic (F-actin turn-over) dynamics of F-actin at the single-filament level in dendritic spines. We found that F-actin in dendritic spines exhibits highly heterogeneous kinematic dynamics at the individual filament level, with simultaneous actin flows in both retrograde and anterograde directions. At the ensemble level, movements of filaments integrate into a net retrograde flow of approximately 138 nm/min. These results suggest a weakly polarized F-actin network that consists of mostly short filaments in dendritic spines.

Effect of Ionizing Radiation on the Mechanical and Structural Properties of Graphite Fiber Reinforced Composites. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Wolf, Kay Woodroof

1982-01-01

Graphite/epoxy (T300/5208) and graphite/polyimide composites (C6000/PMR 15) were exposed to various levels of 0.5 MeV electron radiation with the maximum dose being 10,000 Mrad. A three point bending test was used to evaluate the ultimate stress and modulus of the composites. In all composites except transverse samples of C6000/PMR 15 ultimate stress values remained approximately constant or increased slightly. The modulus values remained approximately constant for all composite types regardless of the radiation level. Interfacial aspects of composites were studied. Interlaminar shear tests were performed on T300/5208 and C6000/PMR 15 composites irradiated to 10,000 Mrad. There was an initial increase in interlaminar shear strength (up to 1,000 Mrad) followed by a sharp decrease with further radiation exposure. Using scanning electron microscopy no visual differences in the mode of fracture could be detected between ruptured control samples and those exposed to various levels of radiation. Electron spectroscopy for chemical analysis (ESCA) revealed little change in the surface elements present in control and highly irradiated T300/5208 composite samples.

Phenotypic variation among familial hypercholesterolemics heterozygous for either one of two Afrikaner founder LDL receptor mutations.

PubMed

Kotze, M J; De Villiers, W J; Steyn, K; Kriek, J A; Marais, A D; Langenhoven, E; Herbert, J S; Graadt Van Roggen, J F; Van der Westhuyzen, D R; Coetzee, G A

1993-10-01

Two common founder-related gene mutations that affect the low-density lipoprotein receptor (LDLR) are responsible for approximately 80% of familial hypercholesterolemia (FH) in South African Afrikaners. The FH Afrikaner-1 (FH1) mutation (Asp206-->Glu) in exon 4 results in defective receptors with approximately 20% of normal activity, whereas the FH Afrikaner-2 (FH2) mutation (Val408-->Met) in exon 9 completely abolishes LDLR activity (< 2% normal activity). We analyzed the contribution of these mutations and other factors on the variation of hypercholesterolemia and clinical features in Afrikaner FH heterozygotes. The type of FH mutation, plasma triglyceride levels, and age of patients each contributed significantly to the variation in hypercholesterolemia, whereas smoking status, high-density lipoprotein cholesterol levels, and gender had no influence. Although all FH heterozygotes had frank hypercholesterolemia, patients with the FH1 mutation had significantly lower cholesterol levels than those with the FH2 mutation. FH1 heterozygotes also tended to have milder clinical features. The differences between the two FH groups could not be explained by a difference in the common apolipoprotein E variants. This study demonstrates that mutational heterogeneity in the LDLR gene influences the phenotypic expression of heterozygous FH.

The intensity dependence of lesion position shift during focused ultrasound surgery.

PubMed

Meaney, P M; Cahill, M D; ter Haar, G R

2000-03-01

Knowledge of the spatial distribution of intensity loss from an ultrasonic beam is critical for predicting lesion formation in focused ultrasound (US) surgery (FUS). To date, most models have used linear propagation models to predict intensity profiles required to compute the temporally varying temperature distributions used to compute thermal dose contours. These are used to predict the extent of thermal damage. However, these simulations fail to describe adequately the abnormal lesion formation behaviour observed during ex vivo experiments in cases for which the transducer drive levels are varied over a wide range. In such experiments, the extent of thermal damage has been observed to move significantly closer to the transducer with increased transducer drive levels than would be predicted using linear-propagation models. The first set of simulations described herein use the KZK (Khokhlov-Zabolotskaya-Kuznetsov) nonlinear propagation model with the parabolic approximation for highly focused US waves to demonstrate that both the peak intensity and the lesion positions do, indeed, move closer to the transducer. This illustrates that, for accurate modelling of heating during FUS, nonlinear effects should be considered. Additionally, a first order approximation has been employed that attempts to account for the abnormal heat deposition distributions that accompany high transducer drive level FUS exposures where cavitation and boiling may be present. The results of these simulations are presented. It is suggested that this type of approach may be a useful tool in understanding thermal damage mechanisms.

High-frequency sediment-level oscillations in the swash zone

USGS Publications Warehouse

Sallenger, A.H.; Richmond, B.M.

1984-01-01

Sediment-level oscillations with heights of about 6 cm and shore-normal lengths of order 10 m have been measured in the swash zone of a high-energy, coarse-sand beach. Crests of oscillations were shore parallel and continuous alongshore. The oscillations were of such low steepness (height-to-length ratio approximately 0.006) that they were difficult to detect visually. The period of oscillation ranged between 6 and 15 min and decreased landward across the swash zone. The sediment-level oscillations were progressive landward with an average migration rate in the middle to upper swash zone of 0.8 m min-1. Migration was caused mostly by erosion on the seaward flank of the crest of an oscillation during a period of net seaward sediment transport. Thus, the observed migration was a form migration landward rather than a migration involving net landward sediment transport. The observed sediment-level oscillations were different than sand waves or other swash-zone bedforms previously described. ?? 1984.

S-phenyl-N-acetylcysteine in urine of rats and workers after exposure to benzene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jongeneelen, F.J.; Dirven, H.A.; Leijdekkers, C.M.

1987-05-01

An HPLC method for the determination of S-phenyl-N-acetylcysteine in urine is described. The sensitivity is 6 mumol/L (CV = 9%) urine. Exposure of rats to six different concentrations of benzene, ranging from 0-30 ppm, was highly associated with urinary excretion of S-phenyl-N-acetylcysteine (r = 0.86) and with total phenol (r = 0.81). A background level of phenol was found in urine of both non-exposed rats and of non-exposed referents. However, no background excretion of S-phenyl-N-acetylcysteine was found, either in rats or in humans. In urine of exposed rats, the level of S-phenyl-N-acetylcysteine was approximately five times lower than the phenolmore » level. Workers occupationally exposed to benzene, showing high levels of urinary phenol, revealed low concentrations of urinary S-phenyl-N-acetylcysteine. The biological monitoring of industrial exposure to benzene by determination of S-phenyl-N-acetylcysteine in urine is not better than the determination of phenol in urine.« less

Heterogeneity in the Relationship of Substance Use to Risky Sexual Behavior Among Justice-Involved Youth: A Regression Mixture Modeling Approach.

PubMed

Schmiege, Sarah J; Bryan, Angela D

2016-04-01

Justice-involved adolescents engage in high levels of risky sexual behavior and substance use, and understanding potential relationships among these constructs is important for effective HIV/STI prevention. A regression mixture modeling approach was used to determine whether subgroups could be identified based on the regression of two indicators of sexual risk (condom use and frequency of intercourse) on three measures of substance use (alcohol, marijuana and hard drugs). Three classes were observed among n = 596 adolescents on probation: none of the substances predicted outcomes for approximately 18 % of the sample; alcohol and marijuana use were predictive for approximately 59 % of the sample, and marijuana use and hard drug use were predictive in approximately 23 % of the sample. Demographic, individual difference, and additional sexual and substance use risk variables were examined in relation to class membership. Findings are discussed in terms of understanding profiles of risk behavior among at-risk youth.

Cross sections and rate coefficients for inner-shell excitation of Li-like ions with 6 < Z < 42

NASA Astrophysics Data System (ADS)

Safronova, U. I.; Safronova, M. S.; Kato, T.

1996-07-01

Excitation cross sections and rate coefficients by electron impact were calculated for the 1s22s-1s2s2p, 1s22s-1s2s2 and 1s22s-1s2p2 transitions of the Li-like ions (C IV, N V, O VI, Ne VIII, Mg X, Al XI, Si XII, S XIV, Ar XVI, Ca XVIII, Ti XX, Fe XXIV, Ni XXVI, Zn XXVIII, Ge XXX, Se XXXII, Kr XXXIV and Mo XXXX) in the Coulomb-Born approximation with exchange including relativistic effects and configuration interaction. Level energies, mixing coefficients and transition wavelengths and probabilities were also computed. Calculations performed by the 1/Z perturbation theory and Coulomb-Born approximation are compared with the R-matrix method and the distorted-wave approximation were Z is the nuclear charge. Formulae obtained for the angular factors of n-electron atomic system allow one to generalize this method to an arbitrary system of highly charged ions.

Selective probing of mRNA expression levels within a living cell.

PubMed

Nawarathna, D; Turan, T; Wickramasinghe, H Kumar

2009-08-24

We report on a selective and nondestructive measurement of mRNA (messenger ribonucleic acid) expression levels within a living cell. We first modify an atomic force microscope tip to create a tapered nanoscale coaxial cable. Application of an ac (alternating potential) between the inner and outer electrodes of this cable creates a dielectrophoretic force attracting mRNA molecules toward the tip-end which is pretreated with gene specific primers. We selectively extracted and analyzed both high ( approximately 2500) and extremely low (11 0) copy number mRNA from a living cell mRNA in less than 10 s.

Risk management at the stage of design of high-rise construction facilities

NASA Astrophysics Data System (ADS)

Politi, Violetta

2018-03-01

This paper describes the assessment of the probabilistic risk of an accident formed in the process of designing a technically complex facility. It considers values of conditional probabilities of the compliance of load-bearing structures with safety requirements, provides an approximate list of significant errors of the designer and analyzes the relationship between the degree of compliance and the level of danger of errors. It describes and proposes for implementation the regulated procedures related to the assessment of the safety level of constructive solutions and the reliability of the construction process participants.

Reassigning the CaH+ 11Σ → 21Σ vibronic transition with CaD+

NASA Astrophysics Data System (ADS)

Condoluci, J.; Janardan, S.; Calvin, A. T.; Rugango, R.; Shu, G.; Sherrill, C. D.; Brown, K. R.

2017-12-01

We observe vibronic transitions in CaD+ between the 11Σ and 21Σ electronic states by resonance enhanced multiphoton photodissociation spectroscopy in a Coulomb crystal. The vibronic transitions are compared with previous measurements on CaH+. The result is a revised assignment of the CaH+ vibronic levels and a disagreement with multi-state-complete-active-space second-order perturbation theory theoretical calculations by approximately 700 cm-1. Updated high-level coupled-cluster calculations that include core-valence correlations reduce the disagreement between theory and experiment to 300 cm-1.

Identification of a Proteinaceous Component in the Leaf of Moringa Oleifera lam. with Effects on High Serum Creatinine

PubMed Central

Sahoo, S.; Raghavendra, K. M.; Biswas, S.

2014-01-01

Moringa oleifera Lam. has been an important plant in the history of mankind, both for its nutritional and medicinal uses. Apart from bactericidal effects, the parts of this plant have been effectively used in the treatment of circulatory, respiratory, endocrine, digestive as well as neural disorders. Till date, though, there has been no reported activity of the involvement of any proteinaceous extract from M. oleifera on high levels of serum creatinine. To address this issue, blood samples with high levels of serum creatinine (2 mg/dl and above) were treated with leaf extract from M. oleifera. The crude extract was partially purified initially and eventually purified to completion as well. All these proteinaceous fractions were used to treat samples with high levels of serum creatinine as mentioned above. While the treatment of serum sample having high creatinine with crude extract and partially purified protein fractions showed a decrease of approximately 20% in the levels of serum creatinine over a period of 24 h, the samples treated with purified protein fraction reduced the serum creatinine level by 50%. In light of the fact that increased level of serum creatinine levels have adverse downstream effects on the heart, lungs and other organs, this communication assumes significance because it suggests a way of reducing the level of serum creatinine as an emergency measure. Further, the identification and characterisation of this proteinaceous component and possible in vivo experiments would provide a major tool for the treatment of downstream complications associated with increased serum creatinine via a new sources, albeit a natural one. PMID:24799742

Center for Thin Film Studies

DTIC Science & Technology

1991-01-22

highly oriented pyrolitic graphite ( HOPG ) for detailed studies of nucleation and of the development of surface roughness. Using a shadowing technique, we...laser to a temperature of approximately 600’C, a polycrystalline film resulted, as indicated b x-ray diffraction ( XRD ) data shown in Fig. 4. vI Figure 4...stress level rose in films deposited at colder temperatures. Development of second harmonic generation as a technique for evaluation of anisotropy in

Perturbational treatment of spin-orbit coupling for generally applicable high-level multi-reference methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mai, Sebastian; Marquetand, Philipp; González, Leticia

2014-08-21

An efficient perturbational treatment of spin-orbit coupling within the framework of high-level multi-reference techniques has been implemented in the most recent version of the COLUMBUS quantum chemistry package, extending the existing fully variational two-component (2c) multi-reference configuration interaction singles and doubles (MRCISD) method. The proposed scheme follows related implementations of quasi-degenerate perturbation theory (QDPT) model space techniques. Our model space is built either from uncontracted, large-scale scalar relativistic MRCISD wavefunctions or based on the scalar-relativistic solutions of the linear-response-theory-based multi-configurational averaged quadratic coupled cluster method (LRT-MRAQCC). The latter approach allows for a consistent, approximatively size-consistent and size-extensive treatment of spin-orbitmore » coupling. The approach is described in detail and compared to a number of related techniques. The inherent accuracy of the QDPT approach is validated by comparing cuts of the potential energy surfaces of acrolein and its S, Se, and Te analoga with the corresponding data obtained from matching fully variational spin-orbit MRCISD calculations. The conceptual availability of approximate analytic gradients with respect to geometrical displacements is an attractive feature of the 2c-QDPT-MRCISD and 2c-QDPT-LRT-MRAQCC methods for structure optimization and ab inito molecular dynamics simulations.« less

Respiratory hospital admissions associated with PM10 pollution in Utah, Salt Lake, and Cache Valleys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope CA, I.I.I.

This study assessed the association between respiratory hospital admissions and PM10 pollution in Utah, Salt Lake, and Cache valleys during April 1985 through March 1989. Utah and Salt Lake valleys had high levels of PM10 pollution that violated both the annual and 24-h standards issued by the Environmental Protection Agency (EPA). Much lower PM10 levels occurred in the Cache Valley. Utah Valley experienced the intermittent operation of its primary source of PM10 pollution: an integrated steel mill. Bronchitis and asthma admissions for preschool-age children were approximately twice as frequent in Utah Valley when the steel mill was operating versus whenmore » it was not. Similar differences were not observed in Salt Lake or Cache valleys. Even though Cache Valley had higher smoking rates and lower temperatures in winter than did Utah Valley, per capita bronchitis and asthma admissions for all ages were approximately twice as high in Utah Valley. During the period when the steel mill was closed, differences in per capita admissions between Utah and Cache valleys narrowed considerably. Regression analysis also demonstrated a statistical association between respiratory hospital admissions and PM10 pollution. The results suggest that PM10 pollution plays a role in the incidence and severity of respiratory disease.« less

Projections of extreme water level events for atolls in the western Tropical Pacific

NASA Astrophysics Data System (ADS)

Merrifield, M. A.; Becker, J. M.; Ford, M.; Yao, Y.

2014-12-01

Conditions that lead to extreme water levels and coastal flooding are examined for atolls in the Republic of the Marshall Islands based on a recent field study of wave transformations over fringing reefs, tide gauge observations, and wave model hindcasts. Wave-driven water level extremes pose the largest threat to atoll shorelines, with coastal levels scaling as approximately one-third of the incident breaking wave height. The wave-driven coastal water level is partitioned into a mean setup, low frequency oscillations associated with cross-reef quasi-standing modes, and wind waves that reach the shore after undergoing high dissipation due to breaking and bottom friction. All three components depend on the water level over the reef; however, the sum of the components is independent of water level due to cancelling effects. Wave hindcasts suggest that wave-driven water level extremes capable of coastal flooding are infrequent events that require a peak wave event to coincide with mid- to high-tide conditions. Interannual and decadal variations in sea level do not change the frequency of these events appreciably. Future sea-level rise scenarios significantly increase the flooding threat associated with wave events, with a nearly exponential increase in flooding days per year as sea level exceeds 0.3 to 1.0 m above current levels.

Contents and leachability of heavy metals (Pb, Cu, Sb, Zn, As) in soil at the Pantex firing range, Amarillo, Texas.

PubMed

Basunia, S; Landsberger, S

2001-10-01

Pantex firing range soil samples were analyzed for Pb, Cu, Sb, Zn, and As. One hundred ninety-seven samples were collected from the firing range and vicinity area. There was a lack of knowledge about the distribution of Pb in the firing range, so a random sampling with proportional allocation was chosen. Concentration levels of Pb and Cu in the firing range were found to be in the range of 11-4675 and 13-359 mg/kg, respectively. Concentration levels of Sb were found to be in the range of 1-517 mg/kg. However, the Zn and As concentration levels were close to average soil background levels. The Sn concentration level was expected to be higher in the Pantex firing range soil samples. However, it was found to be below the neutron activation analysis (NAA) detection limit of 75 mg/kg. Enrichment factor analysis showed that Pb and Sb were highly enriched in the firing range with average magnitudes of 55 and 90, respectively. Cu was enriched approximately 6 times more than the usual soil concentration levels. Toxicity characteristic leaching procedure (TCLP) was carried out on size-fractionated homogeneous soil samples. The concentration levels of Pb in leachates were found to be approximately 12 times higher than the U.S. Environmental Protection Agency (EPA) regulatory concentration level of 5 mg/L. Sequential extraction (SE) was also performed to characterize Pb and other trace elements into five different fractions. The highest Pb fraction was found with organic matter in the soil.

Glycine betaine accumulation, ionic and water relations of red-beet at contrasting levels of sodium supply

NASA Technical Reports Server (NTRS)

Subbarao, G. V.; Wheeler, R. M.; Levine, L. H.; Stutte, G. W.; Sager, J. C. (Principal Investigator)

2001-01-01

Exposure of plants to sodium (Na) and salinity may increase glycine betaine accumulation in tissues. To study this, red-beet cvs. Scarlet Supreme and Ruby Queen, were grown for 42 days in a growth chamber using a re-circulating nutrient film technique with 0.25 mmol/L K and either 4.75 mmol/L (control) or 54.75 mmol/L (saline) Na (as NaCl). Plants were harvested at weekly intervals and measurements were taken on leaf water relations, leaf photosynthetic rates, chlorophyll fluorescence, chlorophyll levels, glycine betaine levels, and tissue elemental composition. Glycine betaine accumulation increased under salinity and this accumulation correlated with higher tissue levels of Na in both cultivars. Na accounted for 80 to 90% of the total cation uptake under the saline treatment. At final harvest (42 days), K concentrations in laminae ranged from approximately 65-95 micromoles g-1 dry matter (DM), whereas Na in shoot tissue ranged from approximately 3000-4000 micromoles g-1. Leaf sap osmotic potential at full turgor [psi(s100)] increased as lamina Na content increased. Glycine betaine levels of leaf laminae showed a linear relationship with leaf sap [psi(s100)]. Chlorophyll levels, leaf photosynthetic rates, and chlorophyll fluorescence were not affected by Na levels. These results suggest that the metabolic tolerance to high levels of tissue Na in red-beet could be due to its ability to synthesize and regulate glycine betaine production, and to control partitioning of Na and glycine betaine between the vacuole and the cytoplasm.

Impact of different wort boiling temperatures on the beer foam stabilizing properties of lipid transfer protein 1.

PubMed

Van Nierop, Sandra N E; Evans, David E; Axcell, Barry C; Cantrell, Ian C; Rautenbach, Marina

2004-05-19

Beer consumers demand satisfactory and consistent foam stability; thus, it is a high priority for brewers. Beer foam is stabilized by the interaction between certain beer proteins, including lipid transfer protein 1 (LTP1), and isomerized hop alpha-acids, but destabilized by lipids. In this study it was shown that the wort boiling temperature during the brewing process was critical in determining the final beer LTP1 content and conformation. LTP1 levels during brewing were measured by an LTP1 ELISA, using antinative barley LTP1 polyclonal antibodies. It was observed that the higher wort boiling temperatures ( approximately 102 degrees C), resulting from low altitude at sea level, reduced the final beer LTP1 level to 2-3 microg/mL, whereas the lower wort boiling temperatures ( approximately 96 degrees C), resulting from higher altitudes (1800 m), produced LTP1 levels between 17 and 35 microg/mL. Low levels of LTP1 in combination with elevated levels of free fatty acids (FFA) resulted in poor foam stability, whereas beer produced with low levels of LTP1 and FFA had satisfactory foam stability. Previous studies indicated the need for LTP1 denaturing to improve its foam stabilizing properties. However, the results presented here show that LTP1 denaturation reduces its ability to act as a binding protein for foam-damaging FFA. These investigations suggest that wort boiling temperature is an important factor in determining the level and conformation of LTP1, thereby favoring satisfactory beer foam stability.

Frequency of Testing for Dyslipidemia: An Evidence-Based Analysis

PubMed Central

2014-01-01

Background Dyslipidemias include high levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides and low levels of high-density lipoprotein (HDL) cholesterol. Dyslipidemia is a risk factor for cardiovascular disease, which is a major contributor to mortality in Canada. Approximately 23% of the 2009/11 Canadian Health Measures Survey (CHMS) participants had a high level of LDL cholesterol, with prevalence increasing with age, and approximately 15% had a total cholesterol to HDL ratio above the threshold. Objectives To evaluate the frequency of lipid testing in adults not diagnosed with dyslipidemia and in adults on treatment for dyslipidemia. Research Methods A systematic review of the literature set out to identify randomized controlled trials (RCTs), systematic reviews, health technology assessments (HTAs), and observational studies published between January 1, 2000, and November 29, 2012, that evaluated the frequency of testing for dyslipidemia in the 2 populations. Results Two observational studies assessed the frequency of lipid testing, 1 in individuals not on lipid-lowering medications and 1 in treated individuals. Both studies were based on previously collected data intended for a different objective and, therefore, no conclusions could be reached about the frequency of testing at intervals other than the ones used in the original studies. Given this limitation and generalizability issues, the quality of evidence was considered very low. No evidence for the frequency of lipid testing was identified in the 2 HTAs included. Canadian and international guidelines recommend testing for dyslipidemia in individuals at an increased risk for cardiovascular disease. The frequency of testing recommended is based on expert consensus. Conclusions Conclusions on the frequency of lipid testing could not be made based on the 2 observational studies. Current guidelines recommend lipid testing in adults with increased cardiovascular risk, with the frequency of testing based on individual cardiovascular risk. PMID:26316920

Rationale and Design of Randomized Evaluation of Aggressive or Moderate Lipid Lowering Therapy with Pitavastatin in Coronary Artery Disease (REAL-CAD) Trial.

PubMed

Miyauchi, Katsumi; Kimura, Takeshi; Shimokawa, Hiroaki; Daida, Hiroyuki; Iimuro, Satoshi; Iwata, Hiroshi; Ozaki, Yukio; Sakuma, Ichiro; Nakagawa, Yoshihisa; Hibi, Kiyoshi; Hiro, Takafumi; Fukumoto, Yoshihiro; Hokimoto, Seiji; Ohashi, Yasuo; Ohtsu, Hiroshi; Saito, Yasushi; Matsuzaki, Masunori; Nagai, Ryozo

2018-03-30

Large-scale clinical trials in patients in Western countries with coronary artery disease (CAD) have found that aggressive lipid-lowering therapy using high-dose statins reduces cardiovascular (CV) events further than low-dose statins. However, such evidence has not yet been fully established in Asian populations, including in Japan. The Randomized Evaluation of Aggressive or Moderate Lipid-Lowering Therapy with Pitavastatin in Coronary Artery Disease (REAL-CAD) study addresses whether intensification of statin therapy improves clinical outcomes in Japanese patients with CAD.REAL-CAD is a prospective, multicenter, randomized, open-label, blinded-endpoint, physician-initiated phase 4 trial in Japan. The study will recruit up to 12,600 patients with stable CAD. Patients are assigned to receive either pitavastatin 1 mg/day or pitavastatin 4 mg/day. LDL-C levels are expected to reach approximate mean values of 100 mg/dL in the low-dose pitavastatin group and 80 mg/dL in the high-dose group. The primary endpoint is the time to occurrence of a major CV event, including CV death, non-fatal myocardial infarction, non-fatal ischemic stroke, and unstable angina requiring emergency hospitalization during an average of 5 years. The large number of patients and the long follow-up period in the REAL-CAD study should ensure that there is adequate power to definitively determine if reducing LDL-C levels to approximately 80 mg/dL by high-dose statin can provide additional clinical benefit.After the study is completed, we will have categorical evidence on the optimal statin dose and target LDL-C level for secondary prevention in Japanese patients.

Systems and Methods for Implementing High-Temperature Tolerant Supercapacitors

NASA Technical Reports Server (NTRS)

Bugga, Ratnakumar V. (Inventor); Brandon, Erik J. (Inventor); West, William C. (Inventor)

2016-01-01

Systems and methods in accordance with embodiments of the invention implement high-temperature tolerant supercapacitors. In one embodiment, a high-temperature tolerant super capacitor includes a first electrode that is thermally stable between at least approximately 80C and approximately 300C; a second electrode that is thermally stable between at least approximately 80C and approximately 300C; an ionically conductive separator that is thermally stable between at least approximately 80C and 300C; an electrolyte that is thermally stable between approximately at least 80C and approximately 300C; where the first electrode and second electrode are separated by the separator such that the first electrode and second electrode are not in physical contact; and where each of the first electrode and second electrode is at least partially immersed in the electrolyte solution.

Approximate Algorithms for Computing Spatial Distance Histograms with Accuracy Guarantees

PubMed Central

Grupcev, Vladimir; Yuan, Yongke; Tu, Yi-Cheng; Huang, Jin; Chen, Shaoping; Pandit, Sagar; Weng, Michael

2014-01-01

Particle simulation has become an important research tool in many scientific and engineering fields. Data generated by such simulations impose great challenges to database storage and query processing. One of the queries against particle simulation data, the spatial distance histogram (SDH) query, is the building block of many high-level analytics, and requires quadratic time to compute using a straightforward algorithm. Previous work has developed efficient algorithms that compute exact SDHs. While beating the naive solution, such algorithms are still not practical in processing SDH queries against large-scale simulation data. In this paper, we take a different path to tackle this problem by focusing on approximate algorithms with provable error bounds. We first present a solution derived from the aforementioned exact SDH algorithm, and this solution has running time that is unrelated to the system size N. We also develop a mathematical model to analyze the mechanism that leads to errors in the basic approximate algorithm. Our model provides insights on how the algorithm can be improved to achieve higher accuracy and efficiency. Such insights give rise to a new approximate algorithm with improved time/accuracy tradeoff. Experimental results confirm our analysis. PMID:24693210

Poly-Pattern Compressive Segmentation of ASTER Data for GIS

NASA Technical Reports Server (NTRS)

Myers, Wayne; Warner, Eric; Tutwiler, Richard

2007-01-01

Pattern-based segmentation of multi-band image data, such as ASTER, produces one-byte and two-byte approximate compressions. This is a dual segmentation consisting of nested coarser and finer level pattern mappings called poly-patterns. The coarser A-level version is structured for direct incorporation into geographic information systems in the manner of a raster map. GIs renderings of this A-level approximation are called pattern pictures which have the appearance of color enhanced images. The two-byte version consisting of thousands of B-level segments provides a capability for approximate restoration of the multi-band data in selected areas or entire scenes. Poly-patterns are especially useful for purposes of change detection and landscape analysis at multiple scales. The primary author has implemented the segmentation methodology in a public domain software suite.

Small-Scale Gravity Waves in ER-2 MMS/MTP Wind and Temperature Measurements during CRYSTAL-FACE

NASA Technical Reports Server (NTRS)

Wang, L.; Alexander, M. J.; Bui, T. P.; Mahoney, M. J.

2006-01-01

Lower stratospheric wind and temperature measurements made from NASA's high-altitude ER-2 research aircraft during the CRYSTAL-FACE campaign in July 2002 were analyzed to retrieve information on small scale gravity waves (GWs) at the aircraft's flight level (typically approximately 20 km altitude). For a given flight segment, the S-transform (a Gaussian wavelet transform) was used to search for and identify small horizontal scale GW events, and to estimate their apparent horizontal wavelengths. The horizontal propagation directions of the events were determined using the Stokes parameter method combined with the cross S-transform analysis. The vertical temperature gradient was used to determine the vertical wavelengths of the events. GW momentum fluxes were calculated from the cross S-transform. Other wave parameters such as intrinsic frequencies were calculated using the GW dispersion relation. More than 100GW events were identified. They were generally high frequency waves with vertical wavelength of approximately 5 km and horizontal wavelength generally shorter than 20 km. Their intrinsic propagation directions were predominantly toward the east, whereas their ground-based propagation directions were primarily toward the west. Among the events, approximately 20% of them had very short horizontal wavelength, very high intrinsic frequency, and relatively small momentum fluxes, and thus they were likely trapped in the lower stratosphere. Using the estimated GW parameters and the background winds and stabilities from the NCAR/NCEP reanalysis data, we were able to trace the sources of the events using a simple reverse ray-tracing. More than 70% of the events were traced back to convective sources in the troposphere, and the sources were generally located upstream of the locations of the events observed at the aircraft level. Finally, a probability density function of the reversible cooling rate due to GWs was obtained in this study, which may be useful for cirrus cloud models.

Spatial and temporal patterns of shoreline change of a 280-km high-energy disrupted sandy coast from 1950 to 2014: SW France

NASA Astrophysics Data System (ADS)

Castelle, Bruno; Guillot, Benoit; Marieu, Vincent; Chaumillon, Eric; Hanquiez, Vincent; Bujan, Stéphane; Poppeschi, Coline

2018-01-01

A dataset of 15 geo-referenced orthomosaics photos was generated to address long-term shoreline change along approximately 270 km of high-energy sandy coast in SW France between 1950 and 2014. The coast consists of sandy beaches backed by coastal dunes, which are only disrupted by two wide tidal inlets (Arcachon and Maumusson), a wide estuary mouth (Gironde) and a few small wave-dominated inlets and coastal towns. A time and spatially averaged erosion trend of 1.12 m/year is found over 1950-2014, with a local maximum of approximately 11 m/year and a maximum local accretion of approximately 6 m/year, respectively. Maximum shoreline evolutions are observed along coasts adjacent to the inlets and to the estuary mouth, with erosion and accretion alternating over time on the timescale of decades. The two inlet-sandspit systems of Arcachon and Maumusson show a quasi-synchronous behaviour with the two updrift coasts accreting until the 1970s and subsequently eroding since then, which suggests that shoreline change at these locations is controlled by allocyclic mechanisms. Despite sea level rise and the well-established increase in winter wave height over the last decades, there is no capture of significant increase in mean erosion rate. This is hypothesized to be partly the result of relevant coastal dune management works from the 1960s to the 1980s after a long period of coastal dune disrepair during and after the Second World War. This study suggests that long-term shoreline change of high-energy sandy coasts disrupted by inlets and/or estuaries is complex and needs to consider a wide range of parameters including, non-extensively, waves, tides, inlet dynamics, sea level rise, coastal dune management and coastal defences, which challenges the development of reliable long-term coastal evolution numerical models.

Extracorporeal treatment with high-volume continuous venovenous hemodiafiltration and charcoal-based sorbent hemoperfusion for severe metformin-associated lactic acidosis

PubMed Central

Garg, Suneel Kumar; Singh, Omender; Deepak, Desh; Singh, Akhilesh; Yadav, Rohit; Vashist, Kirti

2016-01-01

We present a case of a 49-year-old female with an alleged history of ingestion of approximately 100 tablets of metformin (850 mg each). Investigations revealed severe lactic acidosis with lactate levels of 13.5 mmol/L and pH of 7.17. This indicates severe toxicity and is associated with a high mortality. Charcoal-based sorbent hemoperfusion was done as a desperate effort, as patient continued to deteriorate despite supportive care and high-volume continuous venovenous hemodiafiltration. The patient survived despite metformin-associated lactic acidosis related to severe metformin toxicity. PMID:27275079

Flight is the key to postprandial blood glucose balance in the fruit bats Eonycteris spelaea and Cynopterus sphinx.

PubMed

Peng, Xingwen; He, Xiangyang; Liu, Qi; Sun, Yunxiao; Liu, Hui; Zhang, Qin; Liang, Jie; Peng, Zhen; Liu, Zhixiao; Zhang, Libiao

2017-11-01

Excessive sugar consumption could lead to high blood glucose levels that are harmful to mammalian health and life. Despite consuming large amounts of sugar-rich food, fruit bats have a longer lifespan, raising the question of how these bats overcome potential hyperglycemia. We investigated the change of blood glucose level in nectar-feeding bats ( Eonycteris spelaea ) and fruit-eating bats ( Cynopterus sphinx ) via adjusting their sugar intake and time of flight. We found that the maximum blood glucose level of C. sphinx was higher than 24 mmol/L that is considered to be pathological in other mammals. After C. sphinx bats spent approximately 75% of their time to fly, their blood glucose levels dropped markedly, and the blood glucose of E. spelaea fell to the fast levels after they spent 70% time of fly. Thus, the level of blood glucose elevated with the quantity of sugar intake but declined with the time of flight. Our results indicate that high-intensive flight is a key regulator for blood glucose homeostasis during foraging. High-intensive flight may confer benefits to the fruit bats in foraging success and behavioral interactions and increases the efficiency of pollen and seed disposal mediated by bats.

Chlorella Protein Hydrolysate Attenuates Glucose Metabolic Disorder and Fatty Liver in High-fat Diet-induced Obese Mice.

PubMed

Noguchi, Naoto; Yanagita, Teruyoshi; Rahman, Shaikh Mizanoor; Ando, Yotaro

2016-07-01

Chlorella (Parachlorella beijerinckii) powder is reported to show a preventive effect against metabolic syndromes such as arteriosclerosis, hyperlipidemia, and hypertension. Approximately 60% of the chlorella content is protein. In order to understand the role of chlorella protein, we prepared a chlorella protein hydrolysate (CPH) by protease treatment. Male C57BL/6 mice were divided into three groups: a normal diet group, high-fat diet (HFD) group, and high-fat diet supplemented with CPH (HFD+CPH) group. The CPH administration improved glucose intolerance, insulin sensitivity, and adipose tissue hypertrophy in the high-fat diet-fed mice. In addition, the HFD+CPH group had significantly decreased liver total cholesterol and triglyceride levels compared with those in the HFD group. Furthermore, the HFD+CPH group had a decreased level of monocyte chemotactic protein-1 (MCP-1) in serum and a lower MCP-1 mRNA expression level in adipose tissue compared with the HFD group. The present study suggests that chlorella protein hydrolysate can prevent a high-fat diet-induced glucose disorder and fatty liver by inhibiting adipocyte hypertrophy and reducing the MCP-1 protein and gene expression.

Solving bi-level optimization problems in engineering design using kriging models

NASA Astrophysics Data System (ADS)

Xia, Yi; Liu, Xiaojie; Du, Gang

2018-05-01

Stackelberg game-theoretic approaches are applied extensively in engineering design to handle distributed collaboration decisions. Bi-level genetic algorithms (BLGAs) and response surfaces have been used to solve the corresponding bi-level programming models. However, the computational costs for BLGAs often increase rapidly with the complexity of lower-level programs, and optimal solution functions sometimes cannot be approximated by response surfaces. This article proposes a new method, namely the optimal solution function approximation by kriging model (OSFAKM), in which kriging models are used to approximate the optimal solution functions. A detailed example demonstrates that OSFAKM can obtain better solutions than BLGAs and response surface-based methods, and at the same time reduce the workload of computation remarkably. Five benchmark problems and a case study of the optimal design of a thin-walled pressure vessel are also presented to illustrate the feasibility and potential of the proposed method for bi-level optimization in engineering design.

LX-04 VIOLENCE MEASUREMENTS- STEVEN TESTS IMPACTED BY PROJECTILES SHOT FROM A HOWITZER GUN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chidester, S K; Vandersall, K S; Switzer, L L

Characterization of the reaction violence of LX-04 explosive (85% HMX and 15% Viton A by weight) was obtained from Steven Impact Tests performed above the reaction initiation threshold. A 155 mm Howitzer propellant driven gas gun was used to accelerate the Steven Test projectiles in the range of approximately 170-300 m/s to react (ignite) the LX-04 explosive. Blast overpressure gauges, acoustic microphones, and high-speed photography characterized the level of high explosive reaction violence. A detonation in this velocity range was not observed and when comparing these results (and the Susan test results) with that of other HMX based explosives, LX-04more » has a more gradual reaction violence slope as the impact velocity increases. The high binder content (15%) of the LX-04 explosive is believed to be the key factor to the lower level of violence.« less

Levels of radioactivity in Qatar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Thani, A.A.; Abdul-Majid, S.; Mohammed, K.

The levels of natural and man-made radioactivity in soil and seabed were measured in Qatar to assess radiation exposure levels and to evaluate any radioactive contamination that may have reached the country from fallout or due to the Chernobyl accident radioactivity release. Qatar peninsula is located on the Arabian Gulf, 4500 km from Chernobyl, and has an area of {approximately}11,600 km{sup 2} and a population of {approximately}600,000.

Environmental and genetic influences on flight metabolic rate in the honey bee, Apis mellifera.

PubMed

Harrison, Jon F; Fewell, Jennifer H

2002-10-01

Flying honey bees demonstrate highly variable metabolic rates. The lowest reported values (approximately 0.3 Wg(-1)) occur in tethered bees generating the minimum lift to support their body weight, free-flying 2-day old bees, winter bees, or bees flying at high air temperatures (45 degrees C). The highest values (approximately 0.8 Wg(-1)) occur in foragers that are heavily loaded or flying in low-density air. In different studies, flight metabolic rate has increased, decreased, or remained constant with air temperature. Current research collectively suggests that this variation occurs because flight metabolic rates decrease at thorax temperatures above or below 38 degrees C. At 30 degrees C, approximately 30% of colonial energy is spent during typical foraging, so variation in flight metabolic rate can strongly affect colony-level energy balance. Higher air temperatures tend to increase colonial net gain rates, efficiencies and honey storage rates due to lower metabolic rates during flight and in the hive. Variation in flight metabolism has a clear genetic basis. Different genetic strains of honey bees often differ in flight metabolic rate, and these differences in flight physiology can be correlated with foraging effort, suggesting a possible pathway for selection effects on flight metabolism.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, B. E.; Olson, B. J.; White, J. E.

High-fidelity large eddy simulation (LES) of a low-Atwood number (A = 0.05) Rayleigh-Taylor mixing layer is performed using the tenth-order compact difference code Miranda. An initial multimode perturbation spectrum is specified in Fourier space as a function of mesh resolution such that a database of results is obtained in which each successive level of increased grid resolution corresponds approximately to one additional doubling of the mixing layer width, or generation. The database is then analyzed to determine approximate requirements for self-similarity, and a new metric is proposed to quantify how far a given simulation is from the limit of self-similarity.more » It is determined that mixing layer growth reaches a high degree of self-similarity after approximately 4.5 generations. Statistical convergence errors and boundary effects at late time, however, make it impossible to draw similar conclusions regarding the self-similar growth of more sensitive turbulence parameters. Finally, self-similar turbulence profiles from the LES database are compared with one-dimensional simulations using the k-L-a and BHR-2 Reynolds-averaged Navier-Stokes (RANS) models. The k-L-a model, which is calibrated to reproduce a quadratic turbulence kinetic energy profile for a self-similar mixing layer, is found to be in better agreement with the LES than BHR-2 results.« less

Seismic waves in heterogeneous material: subcell resolution of the discontinuous Galerkin method

NASA Astrophysics Data System (ADS)

Castro, Cristóbal E.; Käser, Martin; Brietzke, Gilbert B.

2010-07-01

We present an important extension of the arbitrary high-order discontinuous Galerkin (DG) finite-element method to model 2-D elastic wave propagation in highly heterogeneous material. In this new approach we include space-variable coefficients to describe smooth or discontinuous material variations inside each element using the same numerical approximation strategy as for the velocity-stress variables in the formulation of the elastic wave equation. The combination of the DG method with a time integration scheme based on the solution of arbitrary accuracy derivatives Riemann problems still provides an explicit, one-step scheme which achieves arbitrary high-order accuracy in space and time. Compared to previous formulations the new scheme contains two additional terms in the form of volume integrals. We show that the increasing computational cost per element can be overcompensated due to the improved material representation inside each element as coarser meshes can be used which reduces the total number of elements and therefore computational time to reach a desired error level. We confirm the accuracy of the proposed scheme performing convergence tests and several numerical experiments considering smooth and highly heterogeneous material. As the approximation of the velocity and stress variables in the wave equation and of the material properties in the model can be chosen independently, we investigate the influence of the polynomial material representation on the accuracy of the synthetic seismograms with respect to computational cost. Moreover, we study the behaviour of the new method on strong material discontinuities, in the case where the mesh is not aligned with such a material interface. In this case second-order linear material approximation seems to be the best choice, with higher-order intra-cell approximation leading to potential instable behaviour. For all test cases we validate our solution against the well-established standard fourth-order finite difference and spectral element method.

Modelling West Antarctic ice sheet growth and collapse through the past five million years.

PubMed

Pollard, David; DeConto, Robert M

2009-03-19

The West Antarctic ice sheet (WAIS), with ice volume equivalent to approximately 5 m of sea level, has long been considered capable of past and future catastrophic collapse. Today, the ice sheet is fringed by vulnerable floating ice shelves that buttress the fast flow of inland ice streams. Grounding lines are several hundred metres below sea level and the bed deepens upstream, raising the prospect of runaway retreat. Projections of future WAIS behaviour have been hampered by limited understanding of past variations and their underlying forcing mechanisms. Its variation since the Last Glacial Maximum is best known, with grounding lines advancing to the continental-shelf edges around approximately 15 kyr ago before retreating to near-modern locations by approximately 3 kyr ago. Prior collapses during the warmth of the early Pliocene epoch and some Pleistocene interglacials have been suggested indirectly from records of sea level and deep-sea-core isotopes, and by the discovery of open-ocean diatoms in subglacial sediments. Until now, however, little direct evidence of such behaviour has been available. Here we use a combined ice sheet/ice shelf model capable of high-resolution nesting with a new treatment of grounding-line dynamics and ice-shelf buttressing to simulate Antarctic ice sheet variations over the past five million years. Modelled WAIS variations range from full glacial extents with grounding lines near the continental shelf break, intermediate states similar to modern, and brief but dramatic retreats, leaving only small, isolated ice caps on West Antarctic islands. Transitions between glacial, intermediate and collapsed states are relatively rapid, taking one to several thousand years. Our simulation is in good agreement with a new sediment record (ANDRILL AND-1B) recovered from the western Ross Sea, indicating a long-term trend from more frequently collapsed to more glaciated states, dominant 40-kyr cyclicity in the Pliocene, and major retreats at marine isotope stage 31 ( approximately 1.07 Myr ago) and other super-interglacials.

Multiplication in Egg Yolk and Survival in Egg Albumen of Genetically and Phenotypically Characterized Salmonella Enteritidis Strains.

PubMed

Gast, Richard K; Guard, Jean; Guraya, Rupa; Locatelli, Aude

2018-06-01

Prompt refrigeration of eggs to prevent the multiplication of Salmonella Enteritidis to high levels during storage is an important practice for reducing the risk of egg-transmitted human illness. The efficacy of egg refrigeration for achieving this goal depends on the interaction among the location of contamination, the ability of contaminant strains to survive or multiply, and the rate at which growth-restricting temperatures are attained. The present study assessed the significance of several characterized genetic and phenotypic properties for the capabilities of 10 Salmonella Enteritidis isolates to multiply rapidly in egg yolk and survive for several days in egg albumen during unrefrigerated (25°C) storage. The growth of small numbers of each Salmonella Enteritidis strain (approximately 10 1 CFU/mL) inoculated into egg yolk samples was determined after 6 and 24 h of incubation. The survival of larger numbers of Salmonella Enteritidis (approximately 10 5 CFU/mL) inoculated into albumen samples was determined at 24 and 96 h of incubation. In yolk, the inoculated Salmonella Enteritidis strains multiplied to mean levels of approximately 10 2.6 CFU/mL after 6 h of incubation and 10 8.3 CFU/mL after 24 h. In albumen, mean levels of approximately 10 4.6 CFU/mL Salmonella Enteritidis were maintained through 96 h. The concentrations of the various Salmonella strains after incubation in either yolk or albumen were distributed over relatively narrow ranges of values. Significant ( P < 0.01) differences observed among individual strains suggested that maintenance of the fimbrial gene sefD may have positive genetic selection value by improving fitness to grow inside egg yolk, whereas the antibiotic resistance gene bla TEM-1 tet(A) appeared to have negative genetic selection value by decreasing fitness to survive in egg albumen.

Endotoxin levels correlate positively with a sedentary lifestyle and negatively with highly trained subjects.

PubMed

Lira, Fabio S; Rosa, Jose C; Pimentel, Gustavo D; Souza, Hélio A; Caperuto, Erico C; Carnevali, Luiz C; Seelaender, Marília; Damaso, Ana R; Oyama, Lila M; de Mello, Marco T; Santos, Ronaldo V

2010-08-04

A sedentary lifestyle increases the risk of developing cardiovascular disease, obesity, and diabetes. This phenomenon is supported by recent studies suggesting a chronic, low-grade inflammation status. Endotoxin derived from gut flora may be key to the development of inflammation by stimulating the secretion of inflammatory factors. This study aimed to examine plasma inflammatory markers and endotoxin levels in individuals with a sedentary lifestyle and/or in highly trained subjects at rest. Fourteen male subjects (sedentary lifestyle n = 7; highly trained subjects n = 7) were recruited. Blood samples were collected after an overnight fast (approximately 12 h). The plasmatic endotoxin, plasminogen activator inhibitor type-1 (PAI-1), monocyte chemotactic protein-1 (MCP1), ICAM/CD54, VCAM/CD106 and lipid profile levels were determined. Endotoxinemia was lower in the highly trained subject group relative to the sedentary subjects (p < 0.002). In addition, we observed a positive correlation between endotoxin and PAI-1 (r = 0.85, p < 0.0001), endotoxin and total cholesterol (r = 0.65; p < 0.01), endotoxin and LDL-c (r = 0.55; p < 0.049) and endotoxin and TG levels (r = 0.90; p < 0.0001). The plasma levels of MCP-1, ICAM/CD54 and VCAM/CD106 did not differ. These results indicate that a lifestyle associated with high-intensity and high-volume exercise induces favorable changes in chronic low-grade inflammation markers and may reduce the risk for diseases such as obesity, diabetes and cardiovascular diseases.

The Quantum Approximation Optimization Algorithm for MaxCut: A Fermionic View

NASA Technical Reports Server (NTRS)

Wang, Zhihui; Hadfield, Stuart; Jiang, Zhang; Rieffel, Eleanor G.

2017-01-01

Farhi et al. recently proposed a class of quantum algorithms, the Quantum Approximate Optimization Algorithm (QAOA), for approximately solving combinatorial optimization problems. A level-p QAOA circuit consists of steps in which a classical Hamiltonian, derived from the cost function, is applied followed by a mixing Hamiltonian. The 2p times for which these two Hamiltonians are applied are the parameters of the algorithm. As p increases, however, the parameter search space grows quickly. The success of the QAOA approach will depend, in part, on finding effective parameter-setting strategies. Here, we analytically and numerically study parameter setting for QAOA applied to MAXCUT. For level-1 QAOA, we derive an analytical expression for a general graph. In principle, expressions for higher p could be derived, but the number of terms quickly becomes prohibitive. For a special case of MAXCUT, the Ring of Disagrees, or the 1D antiferromagnetic ring, we provide an analysis for arbitrarily high level. Using a Fermionic representation, the evolution of the system under QAOA translates into quantum optimal control of an ensemble of independent spins. This treatment enables us to obtain analytical expressions for the performance of QAOA for any p. It also greatly simplifies numerical search for the optimal values of the parameters. By exploring symmetries, we identify a lower-dimensional sub-manifold of interest; the search effort can be accordingly reduced. This analysis also explains an observed symmetry in the optimal parameter values. Further, we numerically investigate the parameter landscape and show that it is a simple one in the sense of having no local optima.

Measurement of volatile organic compounds inside automobiles.

PubMed

Fedoruk, Marion J; Kerger, Brent D

2003-01-01

The objective of the current study was to evaluate the types and concentrations of volatile organic compounds (VOCs) in the passenger cabin of selected sedan automobiles under static (parked, unventilated) and specified conditions of operation (i.e., driving the vehicle using air conditioning alone, vent mode alone, or driver's window half open). Data were collected on five different passenger sedan vehicles from three major automobile manufacturers. Airborne concentrations were assessed using 90-min time-weighted average (TWA) samples under U.S. Environmental Protection Agency (USEPA) Method IP-1B to assess individual VOC compounds and total VOCs (TVOCs) calibrated to toluene. Static vehicle testing demonstrated TVOC levels of approximately 400-800 microg/m(3) at warm interior vehicle temperatures (approximately 80 degrees F), whereas TVOCs at least fivefold higher were observed under extreme heat conditions (e.g., up to 145 degrees F). The profile of most prevalent individual VOC compounds varied considerably according to vehicle brand, age, and interior temperature tested, with predominant compounds including styrene, toluene, and 8- to 12-carbon VOCs. TVOC levels under varied operating conditions (and ventilation) were generally four- to eightfold lower (at approximately 50-160 microg/m(3)) than the static vehicle measurements under warm conditions, with the lowest measured levels generally observed in the trials with the driver's window half open. These data indicate that while relatively high concentrations of certain VOCs can be measured inside static vehicles under extreme heat conditions, normal modes of operation rapidly reduce the inside-vehicle VOC concentrations even when the air conditioning is set on recirculation mode.

Earth mapping - aerial or satellite imagery comparative analysis

NASA Astrophysics Data System (ADS)

Fotev, Svetlin; Jordanov, Dimitar; Lukarski, Hristo

Nowadays, solving the tasks for revision of existing map products and creation of new maps requires making a choice of the land cover image source. The issue of the effectiveness and cost of the usage of aerial mapping systems versus the efficiency and cost of very-high resolution satellite imagery is topical [1, 2, 3, 4]. The price of any remotely sensed image depends on the product (panchromatic or multispectral), resolution, processing level, scale, urgency of task and on whether the needed image is available in the archive or has to be requested. The purpose of the present work is: to make a comparative analysis between the two approaches for mapping the Earth having in mind two parameters: quality and cost. To suggest an approach for selection of the map information sources - airplane-based or spacecraft-based imaging systems with very-high spatial resolution. Two cases are considered: area that equals approximately one satellite scene and area that equals approximately the territory of Bulgaria.

Static, noise, and transition tests of a combined-surface-blowing V/STOL lift/propulsion system

NASA Technical Reports Server (NTRS)

Schoen, A. H.; Kolesar, C. E.; Schaeffer, E. G.

1977-01-01

Efficient thrust vectoring and high levels of circulatory lift were obtained in tests of a half model V/STOL airplane by using a type of externally blown jet flap in which the jet exhaust from wing-mounted cruise fans is directed over both upper and lower surfaces of a flapped wing. Approximately 90% thrust recovery with 87 deg of thrust vectoring was achieved under static conditions using 89 deg of trailing edge flap deflection. The approximately 10% loss appears to be associated primarily with pressure losses due to the flap brackets or slot entries. The jet induced lift was shown to be 55% of the theoretical value for a fullspan jet-flapped wing, even though only 27.5% of the wingspan was immersed in the jet. Steady rate of descent capability in excess of 1,000 feet per minute is predicted. The possibility of significant aerodynamic-noise cancelling when blowing over both surfaces at high velocities is indicated.

Structural analysis of as-deposited and annealed low-temperature gallium arsenide

NASA Astrophysics Data System (ADS)

Matyi, R. J.; Melloch, M. R.; Woodall, J. M.

1993-04-01

The structure of GaAs grown at low substrate temperatures (LT-GaAs) by molecular beam epitaxy has been studied using high resolution X-ray diffraction methods. Double crystal rocking curves from the as-deposited LT-GaAs show well defined interference fringes, indicating a high level of structural perfection. Triple crystal diffraction analysis of the as-deposited sample showed significantly less diffuse scattering near the LT-GaAs 004 reciprocal lattice point compared with the substrate 004 reciprocal lattice point, suggesting that despite the incorporation of approximately 1% excess arsenic, the epitaxial layer had superior crystalline perfection than did the GaAs substrate. Triple crystal scans of annealed LT-GaAs showed an increase in the integrated diffuse intensity by approximately a factor of three as the anneal temperature was increased from 700 to 900°C. Analogous to the effects of SiO2 precipitates in annealed Czochralski silicon, the diffuse intensity is attributed to distortions in the epitaxial LT-GaAs lattice by arsenic precipitates.

Moiré-pattern interlayer potentials in van der Waals materials in the random-phase approximation

NASA Astrophysics Data System (ADS)

Leconte, Nicolas; Jung, Jeil; Lebègue, Sébastien; Gould, Tim

2017-11-01

Stacking-dependent interlayer interactions are important for understanding the structural and electronic properties in incommensurable two-dimensional material assemblies where long-range moiré patterns arise due to small lattice constant mismatch or twist angles. Here we study the stacking-dependent interlayer coupling energies between graphene (G) and hexagonal boron nitride (BN) homo- and heterostructures using high-level random-phase approximation (RPA) ab initio calculations. Our results show that although total binding energies within LDA and RPA differ substantially by a factor of 200%-400%, the energy differences as a function of stacking configuration yield nearly constant values with variations smaller than 20%, meaning that LDA estimates are quite reliable. We produce phenomenological fits to these energy differences, which allows us to calculate various properties of interest including interlayer spacing, sliding energetics, pressure gradients, and elastic coefficients to high accuracy. The importance of long-range interactions (captured by RPA but not LDA) on various properties is also discussed. Parametrizations for all fits are provided.

Saccharomyces cerevisiae vaginitis: transmission from yeast used in baking.

PubMed

Nyirjesy, P; Vazquez, J A; Ufberg, D D; Sobel, J D; Boikov, D A; Buckley, H R

1995-09-01

To determine whether vaginitis due to Saccharomyces cerevisiae can be caused by exposure to exogenous sources of baker's yeast. Eight women with S cerevisiae vaginitis were identified from a cohort of women referred for the evaluation of chronic vaginal symptoms. In those with high-level exposure to exogenous sources of S cerevisiae, isolates from the vagina and those sources were sent in a blinded fashion for contour-clamped homogeneous electric-field electrophoresis. Four women from a cohort of approximately 750 referred patients had high-level exposures to S cerevisiae. In one of these patients, electrophoresis analysis revealed similarities between the strains isolated from her vagina, her husband's fingers, and the yeast he used in his pizza shop. Saccharomyces cerevisiae vaginitis can be the result of the inoculation of this yeast from exogenous sources.

Clinical significance of residual platelet reactivity in patients treated with platelet P2Y12 inhibitors.

PubMed

Thomas, Mark R; Storey, Robert F

2016-09-01

Platelet P2Y12 inhibitors have become an essential component of the treatment strategy for patients with acute coronary syndromes and patients undergoing percutaneous coronary intervention. It is now well-established that approximately 30% of patients treated with the P2Y12 inhibitor clopidogrel display high residual platelet reactivity despite treatment. Patients with high on-treatment platelet reactivity have approximately 2-3-fold greater risk of adverse cardiovascular events and stent thrombosis than those without high platelet reactivity. Conversely, clopidogrel-treated patients with low platelet reactivity display approximately 1.7-fold increased risk of major bleeding. High platelet reactivity is uncommon during treatment with prasugrel and ticagrelor, which achieve a greater reduction in adverse cardiovascular events compared to clopidogrel in ACS patients treated with PCI. This is at the expense of an increase in spontaneous bleeding, however. Minor bleeding events, such as skin haematomas, are more common in prasugrel- and ticagrelor-treated patients that have particularly low platelet reactivity values. These minor bleeding events may occasionally prompt discontinuation of therapy, but their overall prognostic impact is uncertain. However, risk factors for bleeding tend to overlap with risk factors for adverse cardiovascular events. Therefore, patients with these minor bleeding events may also be at higher risk of adverse cardiovascular events, conferring a benefit from low platelet reactivity. Further work is needed to determine the optimal level of platelet reactivity in individuals by taking into account their risk of subsequent adverse cardiovascular events and bleeding. Copyright © 2016 Elsevier Inc. All rights reserved.

Divergent selection on home pen locomotor activity in a chicken model: Selection program, genetic parameters and direct response on activity and body weight

PubMed Central

2017-01-01

General locomotor activity (GLA) in poultry has attracted attention, as it negatively influences production costs (energy expenditure and feed consumption) and welfare parameters (bone strength, litter quality, feather pecking and cannibalism). Laying hen lines diverging in the average level of spontaneous locomotor activity in the home pen were developed by genetic selection using the founder New Hampshire line. Activity was recorded using RFID technology at around five weeks of age during four to five days in the home pen. After initial phenotyping, the least active birds were selected for the low activity line and the most active for the high activity line, with no gene transfer between lines. In each of six generations, approximately ten sires were mated to twenty dams producing 158 to 334 offspring per line per generation. The response to selection was rapid and of a considerable magnitude. In sixth generation, the level of GLA was approximately halved in the low and doubled in the high line compared to the control (7.2, 14.9 and 28.7 recordings/h). Estimated heritability of locomotor activity in the low and high line was 0.38 and 0.33, respectively. Males, in general, were more active than females. High line birds were significantly heavier than low line birds. In fourth, fifth, and sixth generation, low as well as high line birds were lighter than control line birds. This selection experiment demonstrates variation in heritability for GLA and, as a result, genetically diverged lines have been developed. These lines can be used as models for further studies of underlying physiological, neural and molecular genetic mechanisms of spontaneous locomotor activity. PMID:28796792

Divergent selection on home pen locomotor activity in a chicken model: Selection program, genetic parameters and direct response on activity and body weight.

PubMed

Kjaer, Joergen B

2017-01-01

General locomotor activity (GLA) in poultry has attracted attention, as it negatively influences production costs (energy expenditure and feed consumption) and welfare parameters (bone strength, litter quality, feather pecking and cannibalism). Laying hen lines diverging in the average level of spontaneous locomotor activity in the home pen were developed by genetic selection using the founder New Hampshire line. Activity was recorded using RFID technology at around five weeks of age during four to five days in the home pen. After initial phenotyping, the least active birds were selected for the low activity line and the most active for the high activity line, with no gene transfer between lines. In each of six generations, approximately ten sires were mated to twenty dams producing 158 to 334 offspring per line per generation. The response to selection was rapid and of a considerable magnitude. In sixth generation, the level of GLA was approximately halved in the low and doubled in the high line compared to the control (7.2, 14.9 and 28.7 recordings/h). Estimated heritability of locomotor activity in the low and high line was 0.38 and 0.33, respectively. Males, in general, were more active than females. High line birds were significantly heavier than low line birds. In fourth, fifth, and sixth generation, low as well as high line birds were lighter than control line birds. This selection experiment demonstrates variation in heritability for GLA and, as a result, genetically diverged lines have been developed. These lines can be used as models for further studies of underlying physiological, neural and molecular genetic mechanisms of spontaneous locomotor activity.

Neonatal incubators: a toxic sound environment for the preterm infant?*.

PubMed

Marik, Paul E; Fuller, Christopher; Levitov, Alexander; Moll, Elizabeth

2012-11-01

High sound pressure levels may be harmful to the maturing newborn. Current guidelines suggest that the sound pressure levels within a neonatal intensive care unit should not exceed 45 dB(A). It is likely that environmental noise as well as the noise generated by the incubator fan and respiratory equipment may contribute to the total sound pressure levels. Knowledge of the contribution of each component and source is important to develop effective strategies to reduce noise within the incubator. The objectives of this study were to determine the sound levels, sound spectra, and major sources of sound within a modern neonatal incubator (Giraffe Omnibed; GE Healthcare, Helsinki, Finland) using a sound simulation study to replicate the conditions of a preterm infant undergoing high-frequency jet ventilation (Life Pulse, Bunnell, UT). Using advanced sound data acquisition and signal processing equipment, we measured and analyzed the sound level at a dummy infant's ear and at the head level outside the enclosure. The sound data time histories were digitally acquired and processed using a digital Fast Fourier Transform algorithm to provide spectra of the sound and cumulative sound pressure levels (dBA). The simulation was done with the incubator cooling fan and ventilator switched on or off. In addition, tests were carried out with the enclosure sides closed and hood down and then with the enclosure sides open and the hood up to determine the importance of interior incubator reverberance on the interior sound levels With all the equipment off and the hood down, the sound pressure levels were 53 dB(A) inside the incubator. The sound pressure levels increased to 68 dB(A) with all equipment switched on (approximately 10 times louder than recommended). The sound intensity was 6.0 × 10(-8) watts/m(2); this sound level is roughly comparable with that generated by a kitchen exhaust fan on high. Turning the ventilator off reduced the overall sound pressure levels to 64 dB(A) and the sound pressure levels in the low-frequency band of 0 to 100 Hz were reduced by 10 dB(A). The incubator fan generated tones at 200, 400, and 600 Hz that raised the sound level by approximately 2 dB(A)-3 dB(A). Opening the enclosure (with all equipment turned on) reduced the sound levels above 50 Hz by reducing the revereberance within the enclosure. The sound levels, especially at low frequencies, within a modern incubator may reach levels that are likely to be harmful to the developing newborn. Much of the noise is at low frequencies and thus difficult to reduce by conventional means. Therefore, advanced forms of noise control are needed to address this issue.

Early-onset, slow progression of cone photoreceptor dysfunction and degeneration in CNG channel subunit CNGB3 deficiency.

PubMed

Xu, Jianhua; Morris, Lynsie; Fliesler, Steven J; Sherry, David M; Ding, Xi-Qin

2011-06-01

To investigate the progression of cone dysfunction and degeneration in CNG channel subunit CNGB3 deficiency. Retinal structure and function in CNGB3(-/-) and wild-type (WT) mice were evaluated by electroretinography (ERG), lectin cytochemistry, and correlative Western blot analysis of cone-specific proteins. Cone and rod terminal integrity was assessed by electron microscopy and synaptic protein immunohistochemical distribution. Cone ERG amplitudes (photopic b-wave) in CNGB3(-/-) mice were reduced to approximately 50% of WT levels by postnatal day 15, decreasing further to approximately 30% of WT levels by 1 month and to approximately 20% by 12 months of age. Rod ERG responses (scotopic a-wave) were not affected in CNGB3(-/-) mice. Average CNGB3(-/-) cone densities were approximately 80% of WT levels at 1 month and declined slowly thereafter to only approximately 50% of WT levels by 12 months. Expression levels of M-opsin, cone transducin α-subunit, and cone arrestin in CNGB3(-/-) mice were reduced by 50% to 60% by 1 month and declined to 35% to 45% of WT levels by 9 months. In addition, cone opsin mislocalized to the outer nuclear layer and the outer plexiform layer in the CNGB3(-/-) retina. Cone and rod synaptic marker expression and terminal ultrastructure were normal in the CNGB3(-/-) retina. These findings are consistent with an early-onset, slow progression of cone functional defects and cone loss in CNGB3(-/-) mice, with the cone signaling deficits arising from disrupted phototransduction and cone loss rather than from synaptic defects.

Solar Electric Propulsion for Future NASA Missions

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Oleson, Steven R.; Mercer, Carolyn R.

2015-01-01

Use of high-power solar arrays, at power levels ranging from approximately 500 KW to several megawatts, has been proposed for a solar-electric propulsion (SEP) demonstration mission, using a photovoltaic array to provide energy to a high-power xenon-fueled engine. One of the proposed applications of the high-power SEP technology is a mission to rendezvous with an asteroid and move it into lunar orbit for human exploration, the Asteroid Retrieval mission. The Solar Electric Propulsion project is dedicated to developing critical technologies to enable trips to further away destinations such as Mars or asteroids. NASA needs to reduce the cost of these ambitious exploration missions. High power and high efficiency SEP systems will require much less propellant to meet those requirements.

Annoyance from transportation noise: relationships with exposure metrics DNL and DENL and their confidence intervals.

PubMed Central

Miedema, H M; Oudshoorn, C G

2001-01-01

We present a model of the distribution of noise annoyance with the mean varying as a function of the noise exposure. Day-night level (DNL) and day-evening-night level (DENL) were used as noise descriptors. Because the entire annoyance distribution has been modeled, any annoyance measure that summarizes this distribution can be calculated from the model. We fitted the model to data from noise annoyance studies for aircraft, road traffic, and railways separately. Polynomial approximations of relationships implied by the model for the combinations of the following exposure and annoyance measures are presented: DNL or DENL, and percentage "highly annoyed" (cutoff at 72 on a scale of 0-100), percentage "annoyed" (cutoff at 50 on a scale of 0-100), or percentage (at least) "a little annoyed" (cutoff at 28 on a scale of 0-100). These approximations are very good, and they are easier to use for practical calculations than the model itself, because the model involves a normal distribution. Our results are based on the same data set that was used earlier to establish relationships between DNL and percentage highly annoyed. In this paper we provide better estimates of the confidence intervals due to the improved model of the relationship between annoyance and noise exposure. Moreover, relationships using descriptors other than DNL and percentage highly annoyed, which are presented here, have not been established earlier on the basis of a large dataset. PMID:11335190

Anxiety and depression in working-age cancer survivors: a register-based study.

PubMed

Inhestern, Laura; Beierlein, Volker; Bultmann, Johanna Christine; Möller, Birgit; Romer, Georg; Koch, Uwe; Bergelt, Corinna

2017-05-19

Anxiety and depression can be a long-term strain in cancer survivors. Little is known about the emotional situation of cancer survivors who have to deal with work- and family-related issues. The purpose of this study was to investigate anxiety and depression in working-age cancer survivors and associated factors. A register-based sample of 3370 cancer survivors (25 to 55 years at time of diagnosis) diagnosed up to six years prior to the survey was recruited from two German cancer registries. Demographic and medical characteristics as well as self-reported measures were used. Overall, approximately 40% of the survivors reported moderate to high anxiety scores and approximately 20% reported moderate to high depression scores. Compared to the general population, working-age cancer survivors were more anxious but less depressed (p < .001). Subgroups with regard to time since diagnosis did not differ in anxiety or depression. Anxiety and depression in cancer survivors were associated with various variables. Better social support, family functioning and physical health were associated with lower anxiety and depression. Overall, we found higher anxiety levels in cancer survivors of working-age than in the general population. A considerable portion of cancer survivors reported moderate to high levels of anxiety and depression. The results indicate the need for psychosocial screening and psycho-oncological support e.g. in survivorship programs for working-age cancer survivors. Assessing the physical health, social support and family background might help to identify survivors at risk for higher emotional distress.

Low asialoglycoprotein receptor expression as markers for highly proliferative potential hepatocytes.

PubMed

Ise, H; Sugihara, N; Negishi, N; Nikaido, T; Akaike, T

2001-07-13

Development of a reliable method to isolate highly proliferative potential hepatocytes will provide insight into the molecular mechanisms of liver regeneration, as well as proving crucial for the development of a biohybrid artificial liver. The aim of this study is to isolate highly proliferative, e.g., progenitor-like, hepatocytes. To this end, we fractionated hepatocytes expressing low and high levels of the asialoglycoprotein receptor (ASGP-R) based on the difference in their adhesion to poly[N-p-vinylbenzyl-O-beta-d-galactopyranosyl-(1-->4)-d-gluconamide] (PVLA), and examined the proliferative activity and gene expression of these fractionated hepatocytes. The results showed that approximately 0.5 to 1% of the total number of hepatocytes, which showed low adhesion to PVLA, expressed low levels of the ASGP-R, while the rest of hepatocyte population with high adhesion to PVLA expressed high levels of the ASGP-R. Interestingly hepatocytes with low ASGP-R expression levels had much higher DNA synthesizing activity (i.e., are much more proliferative) than those with high ASGP-R expression levels. Moreover, hepatocytes with low ASGP-R expression levels expressed higher levels of epidermal growth factor receptor (EGF-R), CD29 (beta1 integrin) and CD49f (alpha6 integrin) and lower levels of glutamine synthetase than those with high ASGP-R expression. These findings suggested that hepatocytes with low adhesion to PVLA due to their low ASGP-R expression could be potential candidates for progenitor-like hepatocytes due to their high proliferative capacity; hence, the low expression of the ASGP-R could be a unique marker for progenitor hepatocytes. The isolation of hepatocytes with different functional phenotypes using PVLA may provide a new research tool for a better understanding of the biology of hepatocytes and the mechanisms regulating their proliferation and differentiation in health and disease. Copyright 2001 Academic Press.

atlant: Advanced Three Level Approximation for Numerical Treatment of Cosmological Recombination

NASA Astrophysics Data System (ADS)

Kholupenko, E. E.; Ivanchik, A. V.; Balashev, S. A.; Varshalovich, D. A.

2011-10-01

atlant is a public numerical code for fast calculations of cosmological recombination of primordial hydrogen-helium plasma is presented. This code is based on the three-level approximation (TLA) model of recombination and allows us to take into account some "fine" physical effects of cosmological recombination simultaneously with using fudge factors.

Systematic Improvement of Potential-Derived Atomic Multipoles and Redundancy of the Electrostatic Parameter Space.

PubMed

Jakobsen, Sofie; Jensen, Frank

2014-12-09

We assess the accuracy of force field (FF) electrostatics at several levels of approximation from the standard model using fixed partial charges to conformational specific multipole fits including up to quadrupole moments. Potential-derived point charges and multipoles are calculated using least-squares methods for a total of ∼1000 different conformations of the 20 natural amino acids. Opposed to standard charge fitting schemes the procedure presented in the current work employs fitting points placed on a single isodensity surface, since the electrostatic potential (ESP) on such a surface determines the ESP at all points outside this surface. We find that the effect of multipoles beyond partial atomic charges is of the same magnitude as the effect due to neglecting conformational dependency (i.e., polarizability), suggesting that the two effects should be included at the same level in FF development. The redundancy at both the partial charge and multipole levels of approximation is quantified. We present an algorithm which stepwise reduces or increases the dimensionality of the charge or multipole parameter space and provides an upper limit of the ESP error that can be obtained at a given truncation level. Thereby, we can identify a reduced set of multipole moments corresponding to ∼40% of the total number of multipoles. This subset of parameters provides a significant improvement in the representation of the ESP compared to the simple point charge model and close to the accuracy obtained using the complete multipole parameter space. The selection of the ∼40% most important multipole sites is highly transferable among different conformations, and we find that quadrupoles are of high importance for atoms involved in π-bonding, since the anisotropic electric field generated in such regions requires a large degree of flexibility.

Hypervelocity Impact Studies on Solar Cell Modules

NASA Technical Reports Server (NTRS)

Brandhorst, Henry W., Jr.; Best, Stevie R.

2001-01-01

Space environmental effects have caused severe problems as satellites move toward increased power and operating voltage levels. The greatest unknown, however, is the effect of high velocity micrometeoroid impacts on high voltage arrays (>200V). Understanding such impact phenomena is necessary for the design of future reliable, high voltage solar arrays, especially for Space Solar Power applications. Therefore, the objective of this work was to study the effect of hypervelocity impacts on high voltage solar arrays. Initially, state of the art, 18% efficient GaAs solar cell strings were targeted. The maximum bias voltage on a two-cell string was -200 V while the adjacent string was held at -140 V relative to the plasma potential. A hollow cathode device provided the plasma. Soda lime glass particles 40-120 micrometers in diameter were accelerated in the Hypervelocity Impact Facility to velocities as high as 11.6 km/sec. Coordinates and velocity were obtained for each of the approximately 40 particle impact sites on each shot. Arcing did occur, and both discharging and recharging of arcs between the two strings was observed. The recharging phenomena appeared to stop at approximately 66V string differential. No arcing was observed at 400 V on concentrator cell modules for the Stretched Lens Array.

Spin-symmetry conversion and internal rotation in high J molecular systems

NASA Astrophysics Data System (ADS)

Mitchell, Justin; Harter, William

2006-05-01

Dynamics and spectra of molecules with internal rotation or rovibrational coupling is approximately modeled by rigid or semi-rigid rotors with attached gyroscopes. Using Rotational Energy (RE)^1 surfaces, high resolution molecular spectra for high angular momentum show two distinct but related phenomena; spin-symmetry conversion and internal rotation. For both cases the high total angular momentum allows for transitions that would otherwise be forbidden. Molecular body-frame J-localization effects associated with tight energy level-clusters dominate the rovibronic spectra of high symmetry molecules, particularly spherical tops at J>10. ^2 The effects include large and widespread spin-symmetry mixing contrary to conventional wisdom^3 about weak nuclear moments. Such effects are discussed showing how RE surface plots may predict them even at low J. Classical dynamics of axially constrained rotors are approximated by intersecting rotational-energy-surfaces (RES) that have (J-S).B.(J-S) forms in the limit of constraints that do no work. Semi-classical eigensolutions are compared to those found by direct diagonalization. ^1 W.G Hater, in Handbook of Atomic, Molecular and Optical Physics, edited by G.W.F Drake (Springer, Germany 2006) ^2 W. G. Harter, Phys. Rev. A24,192-262(1981). ^3 G. Herzberg, Infrared and Raman Spectra (VanNostrand 1945) pp. 458,463.

[Study of cefuroxime in pediatric field (author's transl)].

PubMed

Iwai, N; Sasaki, A; Miyazu, M; Osuga, T; Inaguma, K

1979-11-01

1. Cefuroxime (CXM) was studied for absorption and excretion in 4 pediatric patients given one shot intravenous injection of 20 approximately 25 mg/kg. The following serum levels were determined: 24.5 approximately 38.0 micrograms/ml at 30 minutes (mean 33.3 +/- 6.1 micrograms/ml), 10.0 approximately 17.0 micrograms/ml at 1 hours (mean 13.9 +/- 3.3 micrograms/ml), 3.4 approximately 7.6 micrograms/ml at 2 hours (mean 5.2 +/- 1.9 micrograms/ml, 0.7 approximately 2.1 micrograms/ml at 4 hours (mean 1.3 +/- 0.6 micrograms/ml, 0.1 approximately 0.3 microgram/ml at 6 hours (mean 0.2 +/- 0.1 microgram microgram/ml). Half-life (T 1/2) was 0.65 approximately 0.88 hour (mean 0.75 +/- 0.10 hour). Urinary levels were 1,280 approximately 7,100 micrograms/ml at 0 approximately 2 hours, 96 approximately 3,400 micrograms/ml at 2 approximately 4 hours, 68 approximately 250 micrograms/ml at 4 approximately 6 hours. Urinary recovery rate at 0 approximately 6 hours was 54.1 approximately 74.4% (mean 61.8 +/- 9.4%). 2. From the study on spinal fluid concentration in pediatric patients with Haemophilus influenzae-induced meningitis, the dose of CXM 52.2 mg/kg was given to 1 pediatric case with this disease by one shot intravenous injection. Spinal fluid levels were presumed as 9.0 micrograms/ml at 30 minutes, 6.8 micrograms/ml at 1 hour, 3.8 micrograms/ml at 2 hours and 1.2 micrograms/ml at 4 hours. 3. CXM was studied in 19 pediatric patients with bacterial infection for clinical efficacy, bacteriological effect and side effect. Clinical result was found good in 1 with purulent meningitis; excellent in 9 out of 15 with acute lobar pneumonia or acute bronchopneumonia, and good in remaining 6 cases; good in 2 with acute bronchitis; excellent in 1 with acute pyelonephritis. This represents efficacy ("excellent" plus "good") rate of 100%. Of 5 strains of H. influenzae presumed as causative organisms, 4 were disappeared and 1 was reduced. Two strains of Streptococcus pneumoniae and 1 strain of Escherichia coli were disappeared. No side effect was noted in terms of clinical symptom. Laboratory examination showed elevation of GOT and GPT in 1 case, but these elevated values returned to normal after the end of the CXM treatment.

Mercury, food webs, and marine mammals: implications of diet and climate change for human health.

PubMed

Booth, Shawn; Zeller, Dirk

2005-05-01

We modeled the flow of methyl mercury, a toxic global pollutant, in the Faroe Islands marine ecosystem and compared average human methyl mercury exposure from consumption of pilot whale meat and fish (cod, Gadus morhua) with current tolerable weekly intake (TWI) levels. Under present conditions and climate change scenarios, methyl mercury increased in the ecosystem, translating into increased human exposure over time. However, we saw greater changes as a result of changing fishing mortalities. A large portion of the general human population exceed the TWI levels set by the World Health Organization [WHO; 1.6 microg/kg body weight (bw)], and they all exceed the reference dose (RfD) of 0.1 microg/kg bw/day set by the U.S. Environmental Protection Agency (EPA; equivalent to a TWI of 0.7 microg/kg bw). As a result of an independent study documenting that Faroese children exposed prenatally to methyl mercury had reduced cognitive abilities, pregnant women have decreased their intake of whale meat and were below the TWI levels set by the WHO and the U.S. EPA. Cod had approximately 95% lower methyl mercury concentrations than did pilot whale. Thus, the high and harmful levels of methyl mercury in the diet of Faroe Islanders are driven by whale meat consumption, and the increasing impact of climate change is likely to exacerbate this situation. Significantly, base inflow rates of mercury into the environment would need to be reduced by approximately 50% to ensure levels of intake below the WHO TWI levels, given current levels of whale consumption.

Serum levels of albumin, triglycerides, total protein and glucose in rats are altered after oral treatment with low doses of 13-cis-retinoic acid or all-trans-retinoic acid.

PubMed

Cisneros, F J; Gough, B J; Patton, R E; Ferguson, S A

2005-01-01

Currently used to treat severe acne, 13-cis-retinoic acid (13-cis-RA) is under investigation for its anticancer effects as is the isomer, all-trans-retinoic acid (all-trans-RA). Here, the effects of oral 13-cis-RA or all-trans-RA treatment on serum chemistry, leptin and adiponectin levels were evaluated. Adult Sprague-Dawley rats were gavaged once daily for 7 consecutive days with 13-cis-RA (7.5 or 15 mg kg(-1)), all-trans-RA (10 or 15 mg kg(-1)) (n=24/sex/dose), or soy oil (n=16/sex) and blood was sampled 30-480 min after the last gavage. The body weight was unaffected; however, the liver/body weight ratios were increased by both doses of all-trans-RA. Sex differences were noted for levels of cholesterol, creatine, triglycerides, albumin, alanine aminotransferase and total protein. Both doses of all-trans-RA reduced albumin levels to approximately 90% of the control and total protein levels to approximately 93% of the control while substantially elevating triglyceride levels to approximately 66%-99% above the control. Additionally, triglyceride levels of the 15 mg kg(-1) 13-cis RA group were approximately 62% higher than the controls and total protein levels were approximately 5% less. Glucose levels were affected by sex and RA treatment in that males treated with 15 mg kg(-1) of 13-cis-RA or 10 mg kg(-1) all-trans-RA had lower (13%-19%) levels than the same-sex controls; however, females were not similarly affected. Neither 13-cis-RA nor all-trans-RA treatment had significant effects on the levels of blood urea nitrogen, aspartate amino transferase, leptin or adiponectin. On a mg kg(-1) basis, all-trans-RA was more potent than 13-cis-RA. These results replicate previous findings of RA-induced increased triglyceride levels. Additionally, several new findings indicate there may be sex-specific effects of RA treatment. Finally, neither treatment appeared to alter the typical diurnal cycles of these endpoints. Copyright (c) 2005 John Wiley & Sons, Ltd.

Inband radar cross section of phased arrays with parallel feeds

NASA Astrophysics Data System (ADS)

Flokas, Vassilios

1994-06-01

Approximate formulas for the inband radar cross section of arrays with parallel feeds are presented. To obtain the formulas, multiple reflections are neglected, and devices of the same type are assumed to have identical electrical performance. The approximate results were compared to the results obtained using a scattering matrix formulation. Both methods were in agreement in predicting RCS lobe positions, levels, and behavior with scanning. The advantages of the approximate method are its computational efficiency and its flexibility in handling an arbitrary number of coupler levels.

Detection of pulmonary nodule growth with dose reduced chest tomosynthesis: a human observer study using simulated nodules

NASA Astrophysics Data System (ADS)

Söderman, Christina; Johnsson, Ã. se; Vikgren, Jenny; Rossi Norrlund, Rauni; Molnar, David; Mirzai, Maral; Svalkvist, Angelica; Mânsson, Lars Gunnar; Bâth, Magnus

2016-03-01

Chest tomosynthesis may be a suitable alternative to computed tomography for the clinical task of follow up of pulmonary nodules. The aim of the present study was to investigate the detection of pulmonary nodule growth suggestive of malignancy using chest tomosynthesis. Previous studies have indicated remained levels of detection of pulmonary nodules at dose levels corresponding to that of a conventional lateral radiograph, approximately 0.04 mSv, which motivated to perform the present study this dose level. Pairs of chest tomosynthesis image sets, where the image sets in each pair were acquired of the same patient at two separate occasions, were included in the study. Simulated nodules with original diameters of approximately 8 mm were inserted in the pairs of image sets, simulating situations where the nodule had remained stable in size or increased isotropically in size between the two different imaging occasions. Four different categories of nodule growth were included, corresponding to a volume increase of approximately 21 %, 68 %, 108 % and 250 %. All nodules were centered in the depth direction in the tomosynthesis images. All images were subjected to a simulated dose reduction, resulting in images corresponding to an effective dose of 0.04 mSv. Four observers were given the task of rating their confidence that the nodule was stable in size or not on a five-level rating scale. This was done both before any size measurements were made of the nodule as well as after measurements were performed. Using Receiver operating characteristic analysis, the rating data for the nodules that were stable in size was compared to the rating data for the nodules simulated to have increased in size. Statistically significant differences between the rating distributions for the stable nodules and all of the four nodule growth categories were found. For the three largest nodule growths, nearly perfect detection of nodule growth was seen. In conclusion, the present study indicates that during optimal imaging conditions and for nodules with diameters of approximately 8 mm that grow fairly symmetrically, chest tomosynthesis performed at a dose level corresponding to that of a lateral chest radiograph can, with high sensitivity, differentiate nodules stable in size from nodules growing at rates associated with fast growing malignant nodules.

Absorption Properties of Mediterranean Aerosols Obtained from Multi-year Ground-based and Satellite Remote Sensing Observations

NASA Technical Reports Server (NTRS)

Mallet, M.; Dubovik, O.; Nabat, P.; Dulac, F.; Kahn, R.; Sciare, J.; Paronis, D.; Leon, J. F.

2013-01-01

Aerosol absorption properties are of high importance to assess aerosol impact on regional climate. This study presents an analysis of aerosol absorption products obtained over the Mediterranean Basin or land stations in the region from multi-year ground-based AERONET and satellite observations with a focus on the Absorbing Aerosol Optical Depth (AAOD), Single Scattering Albedo (SSA) and their spectral dependence. The AAOD and Absorption Angstrom Exponent (AAE) data set is composed of daily averaged AERONET level 2 data from a total of 22 Mediterranean stations having long time series, mainly under the influence of urban-industrial aerosols and/or soil dust. This data set covers the 17 yr period 1996-2012 with most data being from 2003-2011 (approximately 89 percent of level-2 AAOD data). Since AERONET level-2 absorption products require a high aerosol load (AOD at 440 nm greater than 0.4), which is most often related to the presence of desert dust, we also consider level-1.5 SSA data, despite their higher uncertainty, and filter out data with an Angstrom exponent less than 1.0 in order to study absorption by carbonaceous aerosols. The SSA data set includes both AERONET level-2 and satellite level-3 products. Satellite-derived SSA data considered are monthly level 3 products mapped at the regional scale for the spring and summer seasons that exhibit the largest aerosol loads. The satellite SSA dataset includes the following products: (i) Multi-angle Imaging SpectroRadiometer (MISR) over 2000-2011, (ii) Ozone Monitoring Instrument (OMI) near-UV algorithm over 2004-2010, and (iii) MODerate resolution Imaging Spectroradiometer (MODIS) Deep-Blue algorithm over 2005-2011, derived only over land in dusty conditions. Sun-photometer observations show that values of AAOD at 440 nm vary between 0.024 +/- 0.01 (resp. 0.040 +/- 0.01) and 0.050 +/- 0.01 (0.055 +/- 0.01) for urban (dusty) sites. Analysis shows that the Mediterranean urban-industrial aerosols appear "moderately" absorbing with values of SSA close to approximately 0.94-0.95 +/- 0.04 (at 440 nm) in most cases except over the large cities of Rome and Athens, where aerosol appears more absorbing (SSA approximately 0.89-0.90 +/- 0.04). The aerosol Absorption Angstrom Exponent (AAE, estimated using 440 and 870 nm) is found to be larger than 1 for most sites over the Mediterranean, a manifestation of mineral dust (iron) and/or brown carbon producing the observed absorption. AERONET level-2 sun-photometer data indicate the existence of a moderate East-West gradient, with higher values over the eastern basin (AAEEast. = 1.39/AAEWest. = 1.33) due to the influence of desert dust. The North-South AAE gradient is more pronounced, especially over the western basin. Our additional analysis of AERONET level-1.5 data also shows that organic absorbing aerosols significantly affect some Mediterranean sites. These results indicate that current climate models treating organics as nonabsorbing over the Mediterranean certainly underestimate the warming effect due to carbonaceous aerosols. Acomparative analysis of the regional SSA variability has been attempted using satellite data. OMI and MODIS data show an absorbing zone (SSA approximately 0.90 at 470-500 nm) over Northeastern Africa that does not appear in the MISR retrievals. In contrast, MISR seems able to observe the East-West SSA gradient during summer, as also detected by AERONET. Also, the analysis of SSA provided by satellites indicates that the aerosol over the Mediterranean Sea appears less absorbing during spring (MAM) than summer (JJA).

Correlation between physics A-levels/A-levels and degree performance

NASA Astrophysics Data System (ADS)

Chadwick, Roy

1985-09-01

The author presents an analysis of 178 students who left Solihull Sixth form College between 1975 and 1981 to do a degree in physics (approximately one third) or engineering (approximately two thirds) at university or polytechnic. The first table is an analysis of physics A-level grade and degree performance; the second table an analysis of the points total for physics A-level plus maths A-level (five for A, four for B, etc.), against degree performances, and the final table an analysis of the points total for physics A-level plus maths A-level plus third A-level (again five for A, four for B, etc.), against degree performance.

Study of weak corrections to Drell-Yan, top-quark pair, and dijet production at high energies with MCFM

DOE PAGES

Campbell, John M.; Wackeroth, Doreen; Zhou, Jia

2016-11-29

Electroweak (EW) corrections can be enhanced at high energies due to the soft or collinear radiation of virtual and real W and Z bosons that result in Sudakov-like corrections of the form αmore » $$l\\atop{W}$$log n(Q 2/M2$$\\atop{W,Z}$$), where α W=α/(4π sin 2θ W) and n ≤ 2l-1. The inclusion of EW corrections in predictions for hadron colliders is, therefore, especially important when searching for signals of possible new physics in distributions probing the kinematic regime Q 2>>M$$2\\atop{V}$$. Next-to-leading order (NLO) EW corrections should also be taken into account when their size [O(α)] is comparable to that of QCD corrections at next-to-next-to-leading order (NNLO) [O(α$$2\\atop{s}$$)]. To this end, we have implemented the NLO weak corrections to the neutral-current Drell-Yan process, top-quark pair production and dijet production in the parton-level Monte Carlo program MCFM. This enables a combined study with the corresponding QCD corrections at NLO and NNLO. We provide both the full NLO weak corrections and their Sudakov approximation since the latter is often used for a fast evaluation of weak effects at high energies and can be extended to higher orders. Finally, with both the exact and approximate results at hand, the validity of the Sudakov approximation can be readily quantified.« less

The complex variable boundary element method: Applications in determining approximative boundaries

USGS Publications Warehouse

Hromadka, T.V.

1984-01-01

The complex variable boundary element method (CVBEM) is used to determine approximation functions for boundary value problems of the Laplace equation such as occurs in potential theory. By determining an approximative boundary upon which the CVBEM approximator matches the desired constant (level curves) boundary conditions, the CVBEM is found to provide the exact solution throughout the interior of the transformed problem domain. Thus, the acceptability of the CVBEM approximation is determined by the closeness-of-fit of the approximative boundary to the study problem boundary. ?? 1984.

Management of monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM).

PubMed

Kyle, Robert A; Rajkumar, S Vincent

2011-06-01

Monoclonal gammopathy of undetermined significance (MGUS) is defined as a serum M protein level of less than 3 g/dL, less than 10% clonal plasma cells in the bone marrow, and the absence of end-organ damage. The prevalence of MGUS is 3.2% in the white population but is approximately twice that high in the black population. MGUS may progress to multiple myeloma, AL amyloidosis, Waldenström macroglobulinemia, or lymphoma. The risk of progression is approximately 1% per year, but the risk continues even after more than 25 years of observation. Risk factors for progression include the size of the serum M protein, the type of serum M protein, the number of plasma cells in the bone marrow, and the serum free light chain ratio. Smoldering (asymptomatic) multiple myeloma (SMM) is characterized by the presence of an M protein level of 3 g/dL or higher and/or 10% or more monoclonal plasma cells in the bone marrow but no evidence of end-organ damage. The overall risk of progression to a malignant condition is 10% per year for the first 5 years, approximately 3% per year for the next 5 years, and 1% to 2% per year for the following 10 years. Patients with both MGUS and SMM must be followed up for their lifetime.

Understanding the Impact of Having a Military Father with Post Traumatic Stress Disorder (PTSD) on Adolescent Children

DTIC Science & Technology

2017-10-01

have mental health , in the same way that we all have physical health . We worry about our physical fitness probably now more than we ever have before...families where the father does not have PTSD. Initial analyses have shown a moderately high level of adolescent mental health problems (approximately...Military Families, Adolescents, Mental Health , Emotional Wellbeing, Family Functioning, Natural Language Processing 16. SECURITY CLASSIFICATION OF: 17

ERBS fuel addendum: Pollution reduction technology program small jet aircraft engines, phase 3

NASA Technical Reports Server (NTRS)

Bruce, T. W.; Davis, F. G.; Kuhn, T. E.; Mongia, H. C.

1982-01-01

A Model TFE731-2 engine with a low emission, variable geometry combustion system was tested to compare the effects of operating the engine on Commercial Jet-A aviation turbine fuel and experimental referee broad specification (ERBS) fuels. Low power emission levels were essentially identical while the high power NOx emission indexes were approximately 15% lower with the EBRS fuel. The exhaust smoke number was approximately 50% higher with ERBS at the takeoff thrust setting; however, both values were still below the EPA limit of 40 for the Model TFE731 engine. Primary zone liner wall temperature ran an average of 25 K higher with ERBS fuel than with Jet-A. The possible adoption of broadened proprties fuels for gas turbine applications is suggested.

Excitonic effects in dense media: breakdown of intrinsic optical bistability

NASA Astrophysics Data System (ADS)

Yudson, V. I.; Reineker, P.

1994-12-01

The steady-state nonlinear response to optical excitation is studied for a thin layer containing “two-level-atoms” (TLA). For a high density of TLAs their dipole-dipole interaction and finite excitonic bandwidth effects become important. We demonstrate that the commonly used local-field approximation ignoring excitonic band effects breaks down. Considering a system of ordered TLAs corresponding to Frenkel excitons in molecular crystals we show that excitonic effects cause an instability of spatially uniform solutions and decrease drastically the existence range of the intrinsic optical bistability of a layer. The possibility of “fast instability”, developing with an increment large in comparison with relaxation rates and the Rabi frequency, also raises the question whether the local field approximation still holds for the description of transient optical phenomena in dense media.

Excitonic effects in dense media: breakdown of intrinsic optical bistability

NASA Astrophysics Data System (ADS)

Yudson, V. I.; Reineker, P.

The steady-state nonlinear response to optical excitation is studied for a thin layer containing “two-level-atoms” (TLA). For a high density of TLAs their dipole-dipole interaction and finite excitonic bandwidth effects become important. We demonstrate that the commonly used local-field approximation ignoring excitonic band effects breaks down. Considering a system of ordered TLAs corresponding to Frenkel excitons in molecular crystals we show that excitonic effects cause an instability of spatially uniform solutions and decrease drastically the existence range of the intrinsic optical bistability of a layer. The possibility of “fast instability”, developing with an increment large in comparison with relaxation rates and the Rabi frequency, also raises the question whether the local field approximation still holds for the description of transient optical phenomena in dense media.

Discovery of localized regions of excess 10-TeV cosmic rays.

PubMed

Abdo, A A; Allen, B; Aune, T; Berley, D; Blaufuss, E; Casanova, S; Chen, C; Dingus, B L; Ellsworth, R W; Fleysher, L; Fleysher, R; Gonzalez, M M; Goodman, J A; Hoffman, C M; Hüntemeyer, P H; Kolterman, B E; Lansdell, C P; Linnemann, J T; McEnery, J E; Mincer, A I; Nemethy, P; Noyes, D; Pretz, J; Ryan, J M; Parkinson, P M Saz; Shoup, A; Sinnis, G; Smith, A J; Sullivan, G W; Vasileiou, V; Walker, G P; Williams, D A; Yodh, G B

2008-11-28

The 7 year data set of the Milagro TeV observatory contains 2.2 x 10(11) events of which most are due to hadronic cosmic rays. These data are searched for evidence of intermediate scale structure. Excess emission on angular scales of approximately 10 degrees has been found in two localized regions of unknown origin with greater than 12sigma significance. Both regions are inconsistent with pure gamma-ray emission with high confidence. One of the regions has a different energy spectrum than the isotropic cosmic-ray flux at a level of 4.6sigma, and it is consistent with hard spectrum protons with an exponential cutoff, with the most significant excess at approximately 10 TeV. Potential causes of these excesses are explored, but no compelling explanations are found.

A Statistical Study of Serum Cholesterol Level by Gender and Race.

PubMed

Tharu, Bhikhari Prasad; Tsokos, Chris P

2017-07-25

Cholesterol level (CL) is growing concerned as health issue in human health since it is considered one of the causes in heart diseases. A study of cholesterol level can provide insight about its nature and characteristics. A cross-sectional study. National Health and Nutrition Examination Survey (NHANS) II was conducted on a probability sample of approximately 28,000 persons in the USA and cholesterol level is obtained from laboratory results. Samples were selected so that certain population groups thought to be at high risk of malnutrition. Study included 11,864 persons for CL cases with 9,602 males and 2,262 females with races: whites, blacks, and others. Non-parametric statistical tests and goodness of fit test have been used to identify probability distributions. The study concludes that the cholesterol level exhibits significant racial and gender differences in terms of probability distributions. The study has concluded that white people are relatively higher at risk than black people to have risk line and high risk cholesterol. The study clearly indicates that black males normally have higher cholesterol. Females have lower variation in cholesterol than males. There exists gender and racial discrepancies in cholesterol which has been identified as lognormal and gamma probability distributions. White individuals seem to be at a higher risk of having high risk cholesterol level than blacks. Females tend to have higher variation in cholesterol level than males.

Estradiol replacement enhances fear memory formation, impairs extinction and reduces COMT expression levels in the hippocampus of ovariectomized female mice.

PubMed

McDermott, Carmel M; Liu, Dan; Ade, Catherine; Schrader, Laura A

2015-02-01

Females experience depression, posttraumatic stress disorder (PTSD), and anxiety disorders at approximately twice the rate of males, but the mechanisms underlying this difference remain undefined. The effect of sex hormones on neural substrates presents a possible mechanism. We investigated the effect of ovariectomy at two ages, before puberty and in adulthood, and 17β-estradiol (E2) replacement administered chronically in drinking water on anxiety level, fear memory formation, and extinction. Based on previous studies, we hypothesized that estradiol replacement would impair fear memory formation and enhance extinction rate. Females, age 4 weeks and 10 weeks, were divided randomly into 4 groups; sham surgery, OVX, OVX+low E2 (200nM), and OVX+high E2 (1000nM). Chronic treatment with high levels of E2 significantly increased anxiety levels measured in the elevated plus maze. In both age groups, high levels of E2 significantly increased contextual fear memory but had no effect on cued fear memory. In addition, high E2 decreased the rate of extinction in both ages. Finally, catechol-O-methyltransferase (COMT) is important for regulation of catecholamine levels, which play a role in fear memory formation and extinction. COMT expression in the hippocampus was significantly reduced by high E2 replacement, implying increased catecholamine levels in the hippocampus of high E2 mice. These results suggest that estradiol enhanced fear memory formation, and inhibited fear memory extinction, possibly stabilizing the fear memory in female mice. This study has implications for a neurobiological mechanism for PTSD and anxiety disorders. Copyright © 2014 Elsevier Inc. All rights reserved.

Feasibility of Screening Adolescents for Suicide Risk in “Real-World” High School Settings

PubMed Central

Hallfors, Denise; Brodish, Paul H.; Khatapoush, Shereen; Sanchez, Victoria; Cho, Hyunsan; Steckler, Allan

2006-01-01

Objectives. We evaluated the feasibility of a population-based approach to preventing adolescent suicide. Methods. A total of 1323 students in 10 high schools completed the Suicide Risk Screen. Screening results, student follow-up, staff feedback, and school responses were assessed. Results. Overall, 29% of the participants were rated as at risk of suicide. As a result of this overwhelming percentage, school staffs chose to discontinue the screening after 2 semesters. In further analyses, about half of the students identified were deemed at high risk on the basis of high levels of depression, suicidal ideation, or suicidal behavior. Priority rankings evidenced good construct validity on correlates such as drug use, hopelessness, and perceived family support. Conclusions. A simpler, more specific screening instrument than the Suicide Risk Screen would identify approximately 11% of urban high school youths for assessment, offering high school officials an important opportunity to identify young people at the greatest levels of need and to target scarce health resources. Our experiences from this study show that lack of feasibility testing greatly contributes to the gap between science and practice. PMID:16380568

Hybridization rapidly reduces fitness of a native trout in the wild

USGS Publications Warehouse

Muhlfeld, C.C.; Kalinowski, S.T.; McMahon, T.E.; Taper, M.L.; Painter, S.; Leary, R.F.; Allendorf, F.W.

2009-01-01

Human-mediated hybridization is a leading cause of biodiversity loss worldwide. How hybridization affects fitness and what level of hybridization is permissible pose difficult conservation questions with little empirical information to guide policy and management decisions. This is particularly true for salmonids, where widespread introgression among non-native and native taxa has often created hybrid swarms over extensive geographical areas resulting in genomic extinction. Here, we used parentage analysis with multilocus microsatellite markers to measure how varying levels of genetic introgression with non-native rainbow trout (Oncorhynchus mykiss) affect reproductive success (number of offspring per adult) of native westslope cutthroat trout (Oncorhynchus clarkii lewisi) in the wild. Small amounts of hybridization markedly reduced fitness of male and female trout, with reproductive success sharply declining by approximately 50 per cent, with only 20 per cent admixture. Despite apparent fitness costs, our data suggest that hybridization may spread due to relatively high reproductive success of first-generation hybrids and high reproductive success of a few males with high levels of admixture. This outbreeding depression suggests that even low levels of admixture may have negative effects on fitness in the wild and that policies protecting hybridized populations may need reconsideration. ?? 2009 The Royal Society.

Changes in atmospheric CO2 - Influence of the marine biota at high latitude

NASA Technical Reports Server (NTRS)

Knox, F.; Mcelroy, M. B.

1984-01-01

Approximately half of the nitrogen and phosphorus entering deep waters of the contemporary ocean are transported from the surface in inorganic form as preformed nutrients. A simple model for ocean chemistry is presented and shown to account for the present level of atmospheric CO2. Fluctuations in preformed nutrients, modulated by changes in insolation and circulation at high latitudes, can result in significant variations in CO2. It is suggested that these changes may account for the apparent control on climate exercised by secular variations in the orbital parameters of the earth.

A Prototype Scintillating-Fibre Tracker for the Cosmic-ray Muon Tomography of Legacy Nuclear Waste Containers

NASA Astrophysics Data System (ADS)

Kaiser, R.; Clarkson, A.; Hamilton, D. J.; Hoek, M.; Ireland, D. G.; Johnston, J. R.; Keri, T.; Lumsden, S.; Mahon, D. F.; McKinnon, B.; Murray, M.; Nutbeam-Tuffs, S.; Shearer, C.; Staines, C.; Yang, G.; Zimmerman, C.

2014-03-01

Cosmic-ray muons are highly-penetrative charged particles observed at sea level with a flux of approximately 1 cm-2 min-1. They interact with matter primarily through Coulomb scattering which can be exploited in muon tomography to image objects within industrial nuclear waste containers. This paper presents the prototype scintillating-fibre detector developed for this application at the University of Glasgow. Experimental results taken with test objects are shown in comparison to results from GEANT4 simulations. These results verify the simulation and show discrimination between the low, medium and high-Z materials imaged.

Premix fuels study applicable to duct burner conditions for a variable cycle engine

NASA Technical Reports Server (NTRS)

Venkataramani, K. S.

1978-01-01

Emission levels and performance of a premixing Jet-A/air duct burner were measured at reference conditions representative of take-off and cruise for a variable cycle engine. In a parametric variation sequence of tests, data were obtained at inlet temperatures of 400, 500 and 600K at equivalence ratios varying from 0.9 to the lean stability limit. Ignition was achieved at all the reference conditions although the CO levels were very high. Significant nonuniformity across the combustor was observed for the emissions at the take-off condition. At a reference Mach number of 0.117 and an inlet temperature of 600K, corresponding to a simulated cruise condition, the NOx emission level was approximately 1 gm/kg-fuel.

Nitric oxide circulates in mammalian plasma primarily as an S-nitroso adduct of serum albumin.

PubMed Central

Stamler, J S; Jaraki, O; Osborne, J; Simon, D I; Keaney, J; Vita, J; Singel, D; Valeri, C R; Loscalzo, J

1992-01-01

We have recently shown that nitric oxide or authentic endothelium-derived relaxing factor generated in a biologic system reacts in the presence of specific protein thiols to form S-nitrosoprotein derivatives that have endothelium-derived relaxing factor-like properties. The single free cysteine of serum albumin, Cys-34, is particularly reactive toward nitrogen oxides (most likely nitrosonium ion) under physiologic conditions, primarily because of its anomalously low pK; given its abundance in plasma, where it accounts for approximately 0.5 mM thiol, we hypothesized that this plasma protein serves as a reservoir for nitric oxide produced by the endothelial cell. To test this hypothesis, we developed a methodology, which involves UV photolytic cleavage of the S--NO bond before reaction with ozone for chemiluminescence detection, with which to measure free nitric oxide, S-nitrosothiols, and S-nitrosoproteins in biologic systems. We found that human plasma contains approximately 7 microM S-nitrosothiols, of which 96% are S-nitrosoproteins, 82% of which is accounted for by S-nitroso-serum albumin. By contrast, plasma levels of free nitric oxide are only in the 3-nM range. In rabbits, plasma S-nitrosothiols are present at approximately 1 microM; 60 min after administration of NG-monomethyl-L-arginine at 50 mg/ml, a selective and potent inhibitor of nitric oxide synthetases, S-nitrosothiols decreased by approximately 40% (greater than 95% of which were accounted for by S-nitrosoproteins, and approximately 80% of which was S-nitroso-serum albumin); this decrease was accompanied by a concomitant increase in mean arterial blood pressure of 22%. These data suggest that naturally produced nitric oxide circulates in plasma primarily complexed in S-nitrosothiol species, principal among which is S-nitroso-serum albumin. This abundant, relatively long-lived adduct likely serves as a reservoir with which plasma levels of highly reactive, short-lived free nitric oxide can be regulated for the maintenance of vascular tone. PMID:1502182

Nitric oxide circulates in mammalian plasma primarily as an S-nitroso adduct of serum albumin.

PubMed

Stamler, J S; Jaraki, O; Osborne, J; Simon, D I; Keaney, J; Vita, J; Singel, D; Valeri, C R; Loscalzo, J

1992-08-15

We have recently shown that nitric oxide or authentic endothelium-derived relaxing factor generated in a biologic system reacts in the presence of specific protein thiols to form S-nitrosoprotein derivatives that have endothelium-derived relaxing factor-like properties. The single free cysteine of serum albumin, Cys-34, is particularly reactive toward nitrogen oxides (most likely nitrosonium ion) under physiologic conditions, primarily because of its anomalously low pK; given its abundance in plasma, where it accounts for approximately 0.5 mM thiol, we hypothesized that this plasma protein serves as a reservoir for nitric oxide produced by the endothelial cell. To test this hypothesis, we developed a methodology, which involves UV photolytic cleavage of the S--NO bond before reaction with ozone for chemiluminescence detection, with which to measure free nitric oxide, S-nitrosothiols, and S-nitrosoproteins in biologic systems. We found that human plasma contains approximately 7 microM S-nitrosothiols, of which 96% are S-nitrosoproteins, 82% of which is accounted for by S-nitroso-serum albumin. By contrast, plasma levels of free nitric oxide are only in the 3-nM range. In rabbits, plasma S-nitrosothiols are present at approximately 1 microM; 60 min after administration of NG-monomethyl-L-arginine at 50 mg/ml, a selective and potent inhibitor of nitric oxide synthetases, S-nitrosothiols decreased by approximately 40% (greater than 95% of which were accounted for by S-nitrosoproteins, and approximately 80% of which was S-nitroso-serum albumin); this decrease was accompanied by a concomitant increase in mean arterial blood pressure of 22%. These data suggest that naturally produced nitric oxide circulates in plasma primarily complexed in S-nitrosothiol species, principal among which is S-nitroso-serum albumin. This abundant, relatively long-lived adduct likely serves as a reservoir with which plasma levels of highly reactive, short-lived free nitric oxide can be regulated for the maintenance of vascular tone.

Association between cardiorespiratory fitness and body fat in girls

PubMed Central

Minatto, Giseli; de Sousa, Thiago Ferreira; de Carvalho, Wellington Roberto Gomes; Ribeiro, Roberto Régis; Santos, Keila Donassolo; Petroski, Edio Luiz

2016-01-01

Abstract Objective: To estimate the prevalence of low cardiorespiratory fitness and its association with excess body fat, considering the sexual maturation and economic level in female adolescents. Methods: Cross-sectional, epidemiological study of 1223 adolescents (10-17 years) from the public school system of Cascavel, PR, Brazil, in 2006. We analyzed the self-assessed sexual maturation level (prepubertal, pubertal and post-pubertal), the economic level (high and low) through a questionnaire and body fat (normal and high) through triceps and subscapular skinfolds. The 20-meter back-and-forth test was applied to estimate maximum oxygen consumption. Cardiorespiratory fitness was assessed according to reference criteria and considered low when the minimum health criterion for age and sex was not met. Chi-square test and logistic regression were applied, with a significance level of 5%. Results: The prevalence of low cardiorespiratory fitness was 51.3%, being associated with all study variables (p<0.001). At the crude analysis, adolescents with high body fat were associated with low cardiorespiratory fitness, when compared to those with normal body fat (OR=2.76; 95%CI: 2.17-3.52). After adjustment by sexual maturation, this association remained valid and showed an effect that was 1.8-fold higher (95%CI: 1.39-2.46) and after adjusting by economic level, the effect was 1.9-fold higher (95%CI: 1.45-2.61). Conclusions: Approximately half of the assessed girls showed unsatisfactory levels of cardiorespiratory fitness for health, which was associated with high body fat, regardless of sexual maturation level and economic level. Effective public health measures are needed, with particular attention to high-risk groups. PMID:27131896

Approximate altitude of water levels in wells completed in the Chicot and Evangeline aquifers in the Houston area, Texas, January-February 1991

USGS Publications Warehouse

Barbie, Dana L.; Kasmarek, Mark C.; Campodonico, Al

1993-01-01

This report is one in a series of reports that annually depict altitudes of water levels since 1977, the most recent of which (Barbie and others, 1991) presented maps of the altitudes of water levels for 1990.  This report was prepared in cooperation with the City of Houston and the Harris-Galveston Coastal Subsidence District, and preents approximate altitudes of water levels in wells in the Chicot and Evangeline aquifers, in the Houston area, January-February 1991.

Analysis of fenbendazole residues in bovine milk by ELISA.

PubMed

Brandon, David L; Bates, Anne H; Binder, Ronald G; Montague, William C; Whitehand, Linda C; Barker, Steven A

2002-10-09

Fenbendazole residues in bovine milk were analyzed by ELISAs using two monoclonal antibodies. One monoclonal antibody (MAb 587) bound the major benzimidazole anthelmintic drugs, including fenbendazole, oxfendazole, and fenbendazole sulfone. The other (MAb 591) was more specific for fenbendazole, with 13% cross-reactivity with the sulfone and no significant binding to the sulfoxide metabolite. The limit of detection of the ELISA method in the milk matrix was 7 ppb for MAb 587 and 3 ppb for MAb 591. Fenbendazole was administered in feed, drench, and paste form to three groups of dairy cattle. Milk was collected immediately before dosing and then every 12 h for 5 days. The ELISA indicated that residue levels varied widely among individual cows in each group. Fenbendazole levels peaked at approximately 12-24 h and declined rapidly thereafter. Metabolites were detected at much higher levels than the parent compound, peaked at approximately 24-36 h, and declined gradually. Residue levels were undetectable by 72 h. The ELISA data correlated well with the total residues determined by chromatographic analysis, but the use of the two separate ELISAs did not afford an advantage over ELISA with the single, broadly reactive MAb 587. The ELISA method could be used to flag high-residue samples in on-site monitoring of fenbendazole in milk and is a potential tool for studying drug pharmacokinetics.

Comparative plasma salicylate and urine salicylurate levels following administration of aspirin, magnesium salicylate, and choline magnesium trisalicylate.

PubMed

Mason, W D

1980-11-01

Eighteen healthy volunteers were administered single doses of commercially available solid dosage forms of aspirin, magnesium salicylate (I), and choline magnesium trisalicylate (II), equivalent to approximately 500 mg of salicylic acid, in a randomized, complete crossover design. Plasma salicylate and urine salicylurate levels were measured by high-pressure liquid chromatography at frequent intervals following dosing; the resultant profiles, areas under the curve (AUC), and percentages of dose excreted as salicylurate were statistically analyzed by an analysis of variance. The plasma salicylate levels following the two dosage forms containing I and II were virtually identical when corrected for small differences in the dose. The plasma salicylic acid level following aspirin was approximately 10% lower during the 1.5--3.0-hr interval due to a portion of unhydrolyzed aspirin, but the dose-corrected AUC for the products tested did not differ significantly (p < 0.05). During the 24 hr following dosing, 66.5 +/- 12.1 68.4 +/- 7.1, and 60.9 +/- 14.1% of the salicylic acid were excreted as urine salicylurate for aspirin, I, and II, respectively, with no significant difference (p < 0.05). Based on this study, there are no significant differences in the rate and extent of absorption of salicylate following the three dosage forms tested, and the elimination kinetics of salicylic acid are not altered by these dosage forms.

Characteristics and knowledge about HIV/AIDS and drug abuse associated with inmates education level within prison populations in Singkawang, West Borneo in 2006.

PubMed

Sigarlaki, Herke G

2008-07-01

to identify the characteristics and knowledge of inmates within prison population in Singkawang city about HIV/AIDS and drugs associated with their education level. a cross-sectional study with 240 respondents was conducted in Singkawang City, West Borneo. The subjects were inmates of prison population. They were interviewed by co-assistant doctors who completed the questionnaire forms about various aspects of knowledge about HIV/AIDS and drugs, including the application of standardized scales on subject characteristics. Data was prepared by using Microsoft Excel 2000 and all data were evaluated by univariate and bivariate analyses. The presentation will be shown in table. at the end of 2006, 91.25% respondents were male and mostly were Malay ethnic group. Moreover, 32.08% of them had formal educational background of Senior High School. Approximately 83.33% of respondents had discovered their status of HIV/AIDS by voluntary counseling and testing (VCT). Their level of knowledge about HIV/AIDS issue particularly that AIDS is caused by HIV was 90.42%. Approximately 48.33% respondents agreed that the risk factor for drug abuse was living with a family member who had taken up smoking and alcoholic consumption. our data indicate that higher education level has better contribution to the better knowledge about HIV/AIDS and drugs.

Function approximation using combined unsupervised and supervised learning.

PubMed

Andras, Peter

2014-03-01

Function approximation is one of the core tasks that are solved using neural networks in the context of many engineering problems. However, good approximation results need good sampling of the data space, which usually requires exponentially increasing volume of data as the dimensionality of the data increases. At the same time, often the high-dimensional data is arranged around a much lower dimensional manifold. Here we propose the breaking of the function approximation task for high-dimensional data into two steps: (1) the mapping of the high-dimensional data onto a lower dimensional space corresponding to the manifold on which the data resides and (2) the approximation of the function using the mapped lower dimensional data. We use over-complete self-organizing maps (SOMs) for the mapping through unsupervised learning, and single hidden layer neural networks for the function approximation through supervised learning. We also extend the two-step procedure by considering support vector machines and Bayesian SOMs for the determination of the best parameters for the nonlinear neurons in the hidden layer of the neural networks used for the function approximation. We compare the approximation performance of the proposed neural networks using a set of functions and show that indeed the neural networks using combined unsupervised and supervised learning outperform in most cases the neural networks that learn the function approximation using the original high-dimensional data.

Oxygen transport of hemoglobin in high-altitude animals (Camelidae).

PubMed

Reynafarje, C; Faura, J; Villavicencio, D; Curaca, A; Reynafarje, B; Oyola, L; Contreras, L; Vallenas, E; Faura, A

1975-05-01

To clarify the mechanisms by which high-altitude Camelidae can adapt to hypoxia, the study of some blood characteristics were carried out in apacas and llamas. The results show that there is a peculiar dissociation curve of hemoglobin in alpacas which permits great affinity of hemoglobin for oxygen at lung level and the release of oxygen at the tissue level with a facility similar to that in man. Fetal hemoglobin was found high in adult alpacas (55 percent). Electrophoretic studies of hemoglobin showed that this pigment has two components, both of which have a very low mobility. Lactic dehydrogenase was found six times higher than in humans. RBC glucose-6-phosphate dehydrogenase was two times higher than in man living at the same altitude. Myoglobin was found to be higher than in man living at altitude. Alpacas have erythrocytes in which the amount of 2,3-DPG is approximately the same as in man. RBC are more resistent to hypotonic solutions than humans. The amount of lactic dehydrogenase, myoglobin, and glucose-6-phosphate dehydrogenase dimishes when alpacas are bought down to sea level.

Dissemination of high-level mupirocin-resistant CC22-MRSA-IV in Saxony

PubMed Central

Monecke, Stefan; Ruppelt-Lorz, Antje; Müller, Elke; Reissig, Annett; Thürmer, Alexander; Shore, Anna C.; Coleman, David C.; Ehricht, Ralf; Jatzwauk, Lutz

2017-01-01

Mupirocin is used for eradicating methicillin-resistant S. aureus (MRSA) in nasal colonization. A plasmid-borne gene, mupA, is associated with high-level mupirocin resistance. Despite the fact that, among all MRSA from a tertiary care center in the German state of Saxony, the prevalence of mupA, encoding high-level mupirocin resistance, was approximately 1% over a 15-year period from 2000–2015, a sharp increase to nearly 20% was observed in 2016/2017. DNA microarray profiling revealed that this was due to the dissemination of a variant of CC22-MRSA-IV (“Barnim Epidemic Strain” or “UK-EMRSA-15”), which, in addition to mecA, harbors mupA, aacA-aphD, qacA, and – in most isolates – erm(C). In order to prevent therapy failures and a further spread of this strain, the use of mupirocin should be more stringently controlled as well as guided by susceptibility testing. In addition, MRSA decolonization regimens that rely on other substances, such as betaisodona, polyhexanide or octenidine, should be considered. PMID:29184755

Branching Fractions and log(gf)s for Weak Lines of Co II connected to the Ground and Low Metastable Levels

NASA Astrophysics Data System (ADS)

Lawler, James Edward; Feigenson, Thomas; Sneden, Chris; Cowan, John J.

2018-01-01

New branching fraction (BF) measurements and log(gf)s of Highly Reliable Lines (HRLs) of Co II are reported. Our measurements test and confirm earlier work by Salih et al. [1985] and Mullman et al. [1998] and expand the earlier BF measurements to include more weak and very weak HRLs. HRLs are UV lines that connect to the population reservoir levels including the ground and low metastable levels of Co+. Such levels contain most of the cobalt in the photospheres of typical F, G, and K stars used in abundance studies. HRLs are essentially immune to departures from Local Thermodynamic Equilibrium (LTE) because they connect to the primary reservoir levels. Lightly-populated high-lying levels of the ion and essentially all levels of the neutral atom have some possibility of being pulled out of LTE through various reactions. Weak and very weak HRLs are needed to determine Co abundances in higher metallicity stars while dominant branches are useful in low metallicity stars of abundance surveys. A large set of HRLs with reliable log(gf)s is desired to avoid blending and saturation problems in photospheric studies. The relative abundance of Fe-peak elements changes as a function of metallicity [e.g. Henry et al. 2010, Sneden et al. 2016] but contributions to the trends from nuclear physics effects in early stars need to be cleanly separated from effect due to limitations of classic photospheric models based on One Dimensional (1D) and LTE approximations. The 1D/LTE approximations of classic photospheric models, which work in well in metal rich dwarf stars such as the Sun, are a source of some concern in Metal Poor (MP) giant stars due to much lower electron and atom pressures. Our new measurements on HRLS of Co II are applied to determine stellar abundances in MP stars.Henry, R. B. C., Cowan, J. J., & Sobeck, J, 2010, ApJ 709, 715Mullman, K. L., Cooper, J. C., & Lawler, J. E. 1998, ApJ, 495, 503Salih, S., Lawler, J. E., & Whaling, W. 1985, PhRvA, 31, 744Sneden et al. 2016, ApJ 817:53Supported by the Univ. of Wisconsin – Hilldale Foundation, NASA grant NNX16AE96G, and NSF grants AST-1516182 & AST1616040.

Lumping of degree-based mean-field and pair-approximation equations for multistate contact processes

NASA Astrophysics Data System (ADS)

Kyriakopoulos, Charalampos; Grossmann, Gerrit; Wolf, Verena; Bortolussi, Luca

2018-01-01

Contact processes form a large and highly interesting class of dynamic processes on networks, including epidemic and information-spreading networks. While devising stochastic models of such processes is relatively easy, analyzing them is very challenging from a computational point of view, particularly for large networks appearing in real applications. One strategy to reduce the complexity of their analysis is to rely on approximations, often in terms of a set of differential equations capturing the evolution of a random node, distinguishing nodes with different topological contexts (i.e., different degrees of different neighborhoods), such as degree-based mean-field (DBMF), approximate-master-equation (AME), or pair-approximation (PA) approaches. The number of differential equations so obtained is typically proportional to the maximum degree kmax of the network, which is much smaller than the size of the master equation of the underlying stochastic model, yet numerically solving these equations can still be problematic for large kmax. In this paper, we consider AME and PA, extended to cope with multiple local states, and we provide an aggregation procedure that clusters together nodes having similar degrees, treating those in the same cluster as indistinguishable, thus reducing the number of equations while preserving an accurate description of global observables of interest. We also provide an automatic way to build such equations and to identify a small number of degree clusters that give accurate results. The method is tested on several case studies, where it shows a high level of compression and a reduction of computational time of several orders of magnitude for large networks, with minimal loss in accuracy.

Controlling the size of alginate gel beads by use of a high electrostatic potential.

PubMed

Klokk, T I; Melvik, J E

2002-01-01

The effect of several parameters on the size of alginate beads produced by use of an electrostatic potential bead generator was examined. Parameters studied included needle diameter, electrostatic potential, alginate solution flow rate, gelling ion concentration and alginate concentration and viscosity, as well as alginate composition. Bead size was found to decrease with increasing electrostatic potential, but only down to a certain level. Minimum bead size was reached at between 2-4 kV/cm for the needles tested. The smallest alginate beads produced (using a needle with inner diameter 0.18 mm) had a mean diameter of approximately 300 microm. Bead size was also found to be dependent upon the flow rate of the fed alginate solution. Increasing the gelling ion concentration resulted in a moderate decrease in bead size. The concentration and viscosity of the alginate solution also had an effect on bead size as demonstrated by an increased bead diameter when the concentration or viscosity was increased. This effect was primarily an effect of the viscosity properties of the solution, which led to changes in the rate of droplet formation in the bead generator. Lowering the flow rate of the alginate solution could partly compensate for the increase in bead size with increased viscosity. For a constant droplet size, alginates with a low G block content (F(GG) approximately 0.20) resulted in approximately 30% smaller beads than alginates with a high G block content (F(GG) approximately 0.60). This is explained as a result of differences in the shrinking properties of the beads.

An improved multilevel Monte Carlo method for estimating probability distribution functions in stochastic oil reservoir simulations

DOE PAGES

Lu, Dan; Zhang, Guannan; Webster, Clayton G.; ...

2016-12-30

In this paper, we develop an improved multilevel Monte Carlo (MLMC) method for estimating cumulative distribution functions (CDFs) of a quantity of interest, coming from numerical approximation of large-scale stochastic subsurface simulations. Compared with Monte Carlo (MC) methods, that require a significantly large number of high-fidelity model executions to achieve a prescribed accuracy when computing statistical expectations, MLMC methods were originally proposed to significantly reduce the computational cost with the use of multifidelity approximations. The improved performance of the MLMC methods depends strongly on the decay of the variance of the integrand as the level increases. However, the main challengemore » in estimating CDFs is that the integrand is a discontinuous indicator function whose variance decays slowly. To address this difficult task, we approximate the integrand using a smoothing function that accelerates the decay of the variance. In addition, we design a novel a posteriori optimization strategy to calibrate the smoothing function, so as to balance the computational gain and the approximation error. The combined proposed techniques are integrated into a very general and practical algorithm that can be applied to a wide range of subsurface problems for high-dimensional uncertainty quantification, such as a fine-grid oil reservoir model considered in this effort. The numerical results reveal that with the use of the calibrated smoothing function, the improved MLMC technique significantly reduces the computational complexity compared to the standard MC approach. Finally, we discuss several factors that affect the performance of the MLMC method and provide guidance for effective and efficient usage in practice.« less

Optimized effective potential method and application to static RPA correlation

NASA Astrophysics Data System (ADS)

Fukazawa, Taro; Akai, Hisazumi

2015-03-01

The optimized effective potential (OEP) method is a promising technique for calculating the ground state properties of a system within the density functional theory. However, it is not widely used as its computational cost is rather high and, also, some ambiguity remains in the theoretical framework. In order to overcome these problems, we first introduced a method that accelerates the OEP scheme in a static RPA-level correlation functional. Second, the Krieger-Li-Iafrate (KLI) approximation is exploited to solve the OEP equation. Although seemingly too crude, this approximation did not reduce the accuracy of the description of the magnetic transition metals (Fe, Co, and Ni) examined here, the magnetic properties of which are rather sensitive to correlation effects. Finally, we reformulated the OEP method to render it applicable to the direct RPA correlation functional and other, more precise, functionals. Emphasis is placed on the following three points of the discussion: (i) level-crossing at the Fermi surface is taken into account; (ii) eigenvalue variations in a Kohn-Sham functional are correctly treated; and (iii) the resultant OEP equation is different from those reported to date.

Heisenberg model of a {Cr8}-cubane magnetic molecule

NASA Astrophysics Data System (ADS)

Luban, Marshall; Kögerler, Paul; Miller, Lance L.; Winpenny, Richard E. P.

2003-05-01

A Heisenberg model of eight CrIII paramagnetic centers (spins s=3/2) at the vertices of a cube with four distinct exchange interactions is found to provide a reasonably accurate description of the magnetic susceptibility of the cubane-type magnetic molecule [Cr8O4(O2CC6H5)16]={Cr8} from 2-290 K for an external field of 0.5 T. We find that two exchange bonds are antiferromagnetic (13, 24 K) and two are ferromagnetic (5, 13.5 K), with an accuracy of approximately 1 K. The determination of the four exchange constants is greatly facilitated using the exact high-temperature expansion of the weak-field susceptibility, effectively reducing the number of unknown parameters to two. We have calculated the thermodynamic properties of the system and these can be compared with the results of future experiments. At temperatures below 0.5 K sharp increases are expected in the magnetization versus external magnetic field at approximately 6 and 12 T and higher fields due to level crossings. Inelastic neutron scattering could check our predictions for the low-lying magnetic energy levels.

Airborne bacterial dispersal during and after dressing and bed changes on burns patients.

PubMed

Bache, Sarah E; Maclean, Michelle; Gettinby, George; Anderson, John G; MacGregor, Scott J; Taggart, Ian

2015-02-01

It is acknowledged that activities such as dressing changes and bed sheet changes are high-risk events; creating surges in levels of airborne bacteria. Burns patients are particularly high dispersers of pathogens; due to their large, often contaminated, wound areas. Prevention of nosocomial cross-contamination is therefore one of the major challenges faced by the burns team. In order to assess the contribution of airborne spread of bacteria, air samples were taken repeatedly throughout and following these events, to quantify levels of airborne bacteria. Air samples were taken at 3-min intervals before, during and after a dressing and bed change on a burns patient using a sieve impaction method. Following incubation, bacterial colonies were enumerated to calculate bacterial colony forming units per m(3) (cfu/m(3)) at each time point. Statistical analysis was performed, whereby the period before the high-risk event took place acted as a control period. The periods during and after the dressing and bed sheet changes were examined for significant differences in airborne bacterial levels relative to the control period. The study was carried out four times, on three patients with burns between 35% total burn surface area (TBSA) and 51% TBSA. There were significant increases in airborne bacteria levels, regardless of whether the dressing change or bed sheet change took place first. Of particular note, is the finding that significantly high levels (up to 2614cfu/m(3)) of airborne bacteria were shown to persist for up to approximately 1h after these activities ended. This is the most accurate picture to date of the rapidly changing levels of airborne bacteria within the room of a burns patient undergoing a dressing change and bed change. The novel demonstration of a significant increase in the airborne bacterial load during these events has implications for infection control on burns units. Furthermore, as these increased levels remained for approximately 1h afterwards, persons entering the room both during and after such events may act as vectors of transmission of infection. It is suggested that appropriate personal protective equipment should be worn by anyone entering the room, and that rooms should be quarantined for a period of time following these events. Airborne bacteria significantly increase during dressing and sheet changes on moderate size burns, and remain elevated for up to an hour following their cessation. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Predictors of summertime heat index levels in New York City apartments

PubMed Central

Quinn, Ashlinn; Kinney, Patrick; Shaman, Jeffrey

2018-01-01

Background During heat waves, fatal overexposure to heat most often occurs at home. It is not known how factors such as building size, floor level, and different types of air conditioning (AC) contribute to excess indoor heat. Methods We monitored indoor temperature and humidity in 36 apartments in New York City during summers 2014 and 2015, and used these values to calculate the indoor heat index (HI). We investigated the role of AC type and building-level factors on indoor HI using multilevel regression models. Results 34 of 36 homes had AC. Central and ductless AC types were associated with the coolest indoor conditions; homes with window and portable AC were significantly warmer. Apartments on the top floor of a building were significantly hotter during heat advisory periods than other apartments regardless of the presence of AC. High indoor HI levels persisted in some homes for approximately one day following the end of the two heat advisory periods. Conclusions We provide concrete evidence of higher heat levels in top floor apartments and in homes with certain types of AC. High heat levels that persist indoors after outdoor heat has subsided may present an underappreciated public health risk. PMID:28107558

Can nature's design be improved upon? High strength, transparent nacre-like nanocomposites with double network of sacrificial cross links.

PubMed

Podsiadlo, Paul; Kaushik, Amit K; Shim, Bong Sup; Agarwal, Ashish; Tang, Zhiyong; Waas, Anthony M; Arruda, Ellen M; Kotov, Nicholas A

2008-11-20

The preparation of a high-strength and highly transparent nacre-like nanocomposite via layer-by-layer assembly technique from poly(vinyl alcohol) (PVA) and Na+-montmorillonite clay nanosheets is reported in this article. We show that a high density of weak bonding interactions between the polymer and the clay particles: hydrogen, dipole-induced dipole, and van der Waals undergoing break-reform deformations, can lead to high strength nanocomposites: sigmaUTS approximately 150 MPa and E' approximately 13 GPa. Further introduction of ionic bonds into the polymeric matrix creates a double network of sacrificial bonds which dramatically increases the mechanical properties: sigmaUTS approximately 320 MPa and E' approximately 60 GPa.

QED loop effects in the spacetime background of a Schwarzschild black hole

NASA Astrophysics Data System (ADS)

Emelyanov, Viacheslav A.

2017-12-01

The black-hole evaporation implies that the quantum-field propagators in a local Minkowski frame acquire a correction, which gives rise to this process. The modification of the propagators causes, in turn, non-trivial local effects due to the radiative/loop diagrams in non-linear QFTs. In particular, there should be imprints of the evaporation in QED, if one goes beyond the tree-level approximation. Of special interest in this respect is the region near the black-hole horizon, which, already at tree level, appears to show highly non-classical features, e.g., negative energy density and energy flux into the black hole.

A gradient-free method for the purification of infective dengue virus for protein-level investigations.

PubMed

Jensen, Stephanie M; Nguyen, Celina T; Jewett, John C

2016-09-01

Dengue virus (DENV) is a mosquito-transmitted flavivirus that infects approximately 100 million people annually. Multi-day protocols for purification of DENV reduce the infective titer due to viral sensitivity to both temperature and pH. Herein we describe a 5-h protocol for the purification of all DENV serotypes, utilizing traditional gradient-free ultracentrifugation followed by selective virion precipitation. This protocol allows for the separation of DENV from contaminating proteins - including intact C6/36 densovirus, for the production of infective virus at high concentration for protein-level analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Early-Onset, Slow Progression of Cone Photoreceptor Dysfunction and Degeneration in CNG Channel Subunit CNGB3 Deficiency

PubMed Central

Xu, Jianhua; Morris, Lynsie; Fliesler, Steven J.; Sherry, David M.

2011-01-01

Purpose. To investigate the progression of cone dysfunction and degeneration in CNG channel subunit CNGB3 deficiency. Methods. Retinal structure and function in CNGB3−/− and wild-type (WT) mice were evaluated by electroretinography (ERG), lectin cytochemistry, and correlative Western blot analysis of cone-specific proteins. Cone and rod terminal integrity was assessed by electron microscopy and synaptic protein immunohistochemical distribution. Results. Cone ERG amplitudes (photopic b-wave) in CNGB3−/− mice were reduced to approximately 50% of WT levels by postnatal day 15, decreasing further to approximately 30% of WT levels by 1 month and to approximately 20% by 12 months of age. Rod ERG responses (scotopic a-wave) were not affected in CNGB3−/− mice. Average CNGB3−/− cone densities were approximately 80% of WT levels at 1 month and declined slowly thereafter to only approximately 50% of WT levels by 12 months. Expression levels of M-opsin, cone transducin α-subunit, and cone arrestin in CNGB3−/− mice were reduced by 50% to 60% by 1 month and declined to 35% to 45% of WT levels by 9 months. In addition, cone opsin mislocalized to the outer nuclear layer and the outer plexiform layer in the CNGB3−/− retina. Cone and rod synaptic marker expression and terminal ultrastructure were normal in the CNGB3−/− retina. Conclusions. These findings are consistent with an early-onset, slow progression of cone functional defects and cone loss in CNGB3−/− mice, with the cone signaling deficits arising from disrupted phototransduction and cone loss rather than from synaptic defects. PMID:21273547

MCD-induced steatohepatitis is associated with hepatic adiponectin resistance and adipogenic transformation of hepatocytes.

PubMed

Larter, Claire Z; Yeh, Matthew M; Williams, Jacqueline; Bell-Anderson, Kim S; Farrell, Geoffrey C

2008-09-01

In these studies, we tested the hypothesis that increased lipid intake would exacerbate the severity of nutritional steatohepatitis. C57Bl/6J mice were fed methionine-and-choline deficient (MCD) diets containing 20% (high) or 5% (low) fat by weight for 3 weeks and compared to lipid-matched controls. MCD feeding increased serum ALT levels and induced hepatic steatosis, lobular inflammation and ballooning degeneration of hepatocytes, irrespective of dietary fat content. Hepatic triglyceride accumulation was similar between high and low-fat MCD-fed mice, but lipoperoxide levels were approximately 3-fold higher in the high-fat MCD-fed animals. Serum adiponectin levels increased in MCD-fed mice, although to a lesser extent in high-fat fed animals. AMPK phosphorylation was correspondingly increased in muscle of MCD-fed mice, but hepatic AMPK phosphorylation decreased, and there was little evidence of PPAR alpha activation, suggesting impaired adiponectin action in the livers of MCD-fed animals. Hepatocyte PPAR gamma mRNA levels increased in MCD-fed mice, and were associated with increased aP2 expression, indicating adipogenic transformation of hepatocytes. Increased dietary lipid intake did not alter steatohepatitis severity in MCD-fed mice despite increased lipoperoxide accumulation. Instead, steatohepatitis was associated with impaired hepatic adiponectin action, and adipogenic transformation of hepatocytes in both low and high-fat MCD-fed mice.

Water-level altitudes 2004 and water-level changes in the Chicot, Evangeline, and Jasper aquifers and compaction 1973-2003 in the Chicot and Evangeline aquifers, Houston-Galveston region, Texas

USGS Publications Warehouse

Kasmarek, Mark C.; Lanning-Rush, Jennifer

2004-01-01

This report is one in an annual series of reports that depicts water-level altitudes and water-level changes in the Chicot, Evangeline, and Jasper aquifers, and compaction in the Chicot and Evangeline aquifers in the Houston-Galveston region. The Houston-Galveston region comprises Harris, Galveston, Fort Bend, Waller, and Montgomery Counties and adjacent parts of Brazoria, Grimes, Walker, San Jacinto, Liberty, and Chambers Counties. The report was prepared in cooperation with the Harris-Galveston Coastal Subsidence District, the City of Houston, the Fort Bend Subsidence District, and the Lone Star Groundwater Conservation District. For the Chicot and Evangeline aquifers, maps show approximate water-level altitudes in 2004, water-level changes from 2003 to 2004, approximate water-level changes from 1977 to 2004, and approximate water-level changes from 1990 to 2004 (figs. 1, 2, 3, 4, 5, 6, 7, 8). For the Jasper aquifer, maps show approximate water-level altitudes in 2004 and water-level changes from 2003 to 2004 and 2000 to 2004 (figs. 9, 10, 11). The report also contains a map showing borehole extensometer (well equipped with compaction monitor) site locations (fig. 12) and graphs showing measured compaction of subsurface material at these sites from 1973 or later to 2003 (fig. 13). The U.S. Geological Survey (USGS) has published annual reports of water-level altitudes and water-level changes for the Chicot and Evangeline aquifers in the Houston-Galveston region since 1979; and annual reports of same for the Fort Bend subregion (Fort Bend County and adjacent areas) since 1990. The USGS published its first water-level-altitude map for the Jasper aquifer in the greater Houston area (primarily Montgomery County) in 2001. The 2004 water-level-altitude and water-level-change maps for the three aquifers are included in this report.

Efficacy of chlorine dioxide against Listeria monocytogenes in brine chilling solutions.

PubMed

Valderrama, W B; Mills, E W; Cutter, C N

2009-11-01

Chilled brine solutions are used by the food industry to rapidly cool ready-to-eat meat products after cooking and before packaging. Chlorine dioxide (ClO(2)) was investigated as an antimicrobial additive to eliminate Listeria monocytogenes. Several experiments were performed using brine solutions made of sodium chloride (NaCl) and calcium chloride (CaCl(2)) inoculated with L. monocytogenes and/or treated with 3 ppm of ClO(2). First, 10 and 20% CaCl(2) and NaCl solutions (pH 7.0) were inoculated with a five-strain cocktail of L. monocytogenes to obtain approximately 7 log CFU/ml and incubated 8 h at 0 degrees C. The results demonstrated that L. monocytogenes survived in 10% CaCl(2), 10 and 20% NaCl, and pure water. L. monocytogenes levels were reduced approximately 1.2 log CFU/ml in 20% CaCl(2). Second, inoculated ( approximately 7 log CFU/ml) brine solutions (10 and 20% NaCl and 10% CaCl(2)) treated with 3 ppm of ClO(2) resulted in a approximately 4-log reduction of the pathogen within 90 s. The same was not observed in a solution of 20% CaCl(2); further investigation demonstrated that high levels of divalent cations interfere with the disinfectant. Spent brine solutions from hot dog and ham chilling were treated with ClO(2) at concentrations of 3 or 30 ppm. At these concentrations, ClO(2) did not reduce L. monocytogenes. Removal of divalent cations and organic material in brine solutions prior to disinfection with ClO(2) should be investigated to improve the efficacy of the compound against L. monocytogenes. The information from this study may be useful to processing establishments and researchers who are investigating antimicrobials in chilling brine solutions.

Respiratory function in pregnancy at sea level and at high altitude.

PubMed

McAuliffe, Fionnuala; Kametas, Nikos; Espinoza, Jimmy; Greenough, Anne; Nicolaides, Kypros

2004-04-01

To determine the effect of pregnancy on respiratory function in a non-Caucasian group and determine whether there was an interaction between pregnancy and altitude of residence. Prospective cross sectional study. Antenatal clinics in Peru, at sea level in Lima and at high altitude in Cerro de Pasco. Peruvian women with singleton pregnancies; 122 living at sea level and 192 living at 4300 m altitude in the Peruvian Andes. At each location, 19 non-pregnant women were also studied. Respiratory function was measured in pregnant and non-pregnant women living at sea level and at 4300 m. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEFR), total lung capacity (TLC), inspiratory capacity (IC), residual volume (RV), expiratory residual volume (ERV) and functional residual capacity (FRC). At sea level, RV and TLC were higher in the third compared with the first trimester (P < 0.05). At high altitude, FEV1 (P < 0.01), ERV (P < 0.01) and FRC (P < 0.01) were lower in the third compared with the first trimester. Pregnant and non-pregnant women at high altitude were 4 cm shorter (P < 0.0001) and had larger lung volumes (P < 0.01); their total lung capacities were approximately 1 L greater than women living at sea level (P < 0.0001). These results suggest that the effect of pregnancy on the respiratory function of healthy women is influenced by altitude of residence.

High-resolution absorption measurements of NH3 at high temperatures: 2100-5500 cm-1

NASA Astrophysics Data System (ADS)

Barton, Emma J.; Yurchenko, Sergei N.; Tennyson, Jonathan; Clausen, Sønnik; Fateev, Alexander

2017-03-01

High-resolution absorption spectra of NH3 in the region 2100-5500 cm-1 at 1027 °C and approximately atmospheric pressure (1045±3 mbar) are measured. An NH3 concentration of 10% in volume fraction is used in the measurements. Spectra are recorded in a high-temperature gas-flow cell using a Fourier Transform Infrared (FTIR) spectrometer at a nominal resolution of 0.09 cm-1. The spectra are analysed by comparison to a variational line list, BYTe, and experimental energy levels determined using the MARVEL procedure. 2308 lines have been assigned to 45 different bands, of which 1755 and 15 have been assigned or observed for the first time in this work.

On the suppression of plasma nonesterified fatty acids by insulin during enhanced intravascular lipolysis in humans.

PubMed

Carpentier, André C; Frisch, Frédérique; Cyr, Denis; Généreux, Philippe; Patterson, Bruce W; Giguère, Robert; Baillargeon, Jean-Patrice

2005-11-01

During the fasting state, insulin reduces nonesterified fatty acid (NEFA) appearance in the systemic circulation mostly by suppressing intracellular lipolysis in the adipose tissue. In the postprandial state, insulin may also control NEFA appearance through enhanced trapping into the adipose tissue of NEFA derived from intravascular triglyceride lipolysis. To determine the contribution of suppression of intracellular lipolysis in the modulation of plasma NEFA metabolism by insulin during enhanced intravascular triglyceride lipolysis, 10 healthy nonobese subjects underwent pancreatic clamps at fasting vs. high physiological insulin level with intravenous infusion of heparin plus Intralipid. Nicotinic acid was administered orally during the last 2 h of each 4-h clamp to inhibit intracellular lipolysis and assess insulin's effect on plasma NEFA metabolism independently of its effect on intracellular lipolysis. Stable isotope tracers of palmitate, acetate, and glycerol were used to assess plasma NEFA metabolism and total triglyceride lipolysis in each participant. The glycerol appearance rate was similar during fasting vs. high insulin level, but plasma NEFA levels were significantly lowered by insulin. Nicotinic acid significantly blunted the insulin-mediated suppression of plasma palmitate appearance and oxidation rates by approximately 60 and approximately 70%, respectively. In contrast, nicotinic acid did not affect the marked stimulation of palmitate clearance by insulin. Thus most of the insulin-mediated reduction of plasma NEFA appearance and oxidation can be explained by suppression of intracellular lipolysis during enhanced intravascular triglyceride lipolysis in healthy humans. Our results also suggest that insulin may affect plasma NEFA clearance independently of the suppression of intracellular lipolysis.

Effects of plasma hydrogenation on trapping properties of dislocations in heteroepitaxial InP/GaAs

NASA Technical Reports Server (NTRS)

Ringel, S. A.; Chatterjee, B.

1994-01-01

In previous work, we have demonstrated the effectiveness of a post-growth hydrogen plasma treatment for passivating the electrical activity of dislocations in metalorganic chemical vapor deposition (MOCVD) grown InP on GaAs substrates by a more than two order of magnitude reduction in deep level concentration and an improvement in reverse bias leakage current by a factor of approximately 20. These results make plasma hydrogenation an extremely promising technique for achieving high efficiency large area and light weight heteroepitaxial InP solar cells for space applications. In this work we investigate the carrier trapping process by dislocations in heteroepitaxial InP/GaAs and the role of hydrogen passivation on this process. It is shown that the charge trapping kinetics of dislocations after hydrogen passivation are significantly altered, approaching point defect-like behavior consistent with a transformation from a high concentration of dislocation-related defect bands within the InP bandgap to a low concentration of individual dislocation related deep levels, before and after passivation. It is further shown that the 'apparent' activation energies of dislocation related deep levels, before and after passivation, reduce by approximately 70 meV as DLTS fill pulse times are increased from 1 microsecond to 1 millisecond. A model is proposed which explains these effects based on a reduction of Coulombic interaction between individual core sites along the dislocation cores by hydrogen incorporation. Knowledge of the trapping properties in these specific structures is important to develop optimum, low loss heteroepitaxial InP cells.

Consequences of sea level variability and sea level rise for Cuban territory

NASA Astrophysics Data System (ADS)

Hernández, M.; Martínez, C. A.; Marzo, O.

2015-03-01

The objective of the present paper was to determine a first approximation of coastal zone flooding by 2100, taking into account the more persistent processes of sea level variability and non-accelerated linear sea level rise estimation to assess the main impacts. The annual linear rate of mean sea level rise in the Cuban archipelago, obtained from the longest tide gauge records, has fluctuated between 0.005 cm/year at Casilda and 0.214 cm/year at Siboney. The main sea level rise effects for the Cuban coastal zone due to climate change and global warming are shown. Monthly and annual mean sea level anomalies, some of which are similar to or higher than the mean sea level rise estimated for halfway through the present century, reinforce the inland seawater penetration due to the semi-daily high tide. The combination of these different events will result in the loss of goods and services, and require expensive investments for adaption.

Air-Sea Interaction in the Gulf of Tehuantepec

NASA Astrophysics Data System (ADS)

Khelif, D.; Friehe, C. A.; Melville, W. K.

2007-05-01

Measurements of meteorological fields and turbulence were made during gap wind events in the Gulf of Tehuantepec using the NSF C-130 aircraft. The flight patterns started at the shore and progressed to approximately 300km offshore with low-level (30m) tracks, stacks and soundings. Parameterizations of the wind stress, sensible and latent heat fluxes were obtained from approximately 700 5 km low-level tracks. Structure of the marine boundary layer as it evolved off-shore was obtained with stack patterns, aircraft soundings and deployment of dropsondes. The air-sea fluxes approximately follow previous parameterizations with some evidence of the drag coefficient leveling out at about 20 meters/sec with the latent heat flux slightly increasing. The boundary layer starts at shore as a gap wind low-level jet, thins as the jet expands out over the gulf, exhibits a hydraulic jump, and then increases due to turbulent mixing.

Study of Near-Threshold Fatigue Crack Propagation in Pipeline Steels in High Pressure Environments

NASA Technical Reports Server (NTRS)

Mitchell, M.

1981-01-01

Near threshold fatigue crack propagation in pipeline steels in high pressure environments was studied. The objective was to determine the level of threshold stress intensity for fatigue crack growth rate behavior in a high strength low alloy X60 pipeline-type steel. Complete results have been generated for gaseous hydrogen at ambient pressure, laboratory air at ambient pressure and approximately 60% relative humidity as well as vacuum of 0.000067 Pa ( 0.0000005 torr) at R-ratios = K(min)/K(max) of 0.1, 0.5, and 0.8. Fatigue crack growth rate behavior in gaseous hydrogen, methane, and methane plus 10 percent hydrogen at 6.89 MPa (100 psi) was determined.

First Year Wilkinson Microwave Anisotropy Probe(WMAP)Observations: The Angular Power Spectrum

NASA Technical Reports Server (NTRS)

Hinshaw, G.; Spergel, D. N.; Verde, L.; Hill, R. S.; Meyer, S. S.; Barnes, C.; Bennett, C. L.; Halpern, M.; Jarosik, N.; Kogut, A.

2003-01-01

We present the angular power spectrum derived from the first-year Wilkinson Microwave Anisotropy Probe (WMAP) sky maps. We study a variety of power spectrum estimation methods and data combinations and demonstrate that the results are robust. The data are modestly contaminated by diffuse Galactic foreground emission, but we show that a simple Galactic template model is sufficient to remove the signal. Point sources produce a modest contamination in the low frequency data. After masking approximately 700 known bright sources from the maps, we estimate residual sources contribute approximately 3500 mu sq Kappa at 41 GHz, and approximately 130 mu sq Kappa at 94 GHz, to the power spectrum [iota(iota + 1)C(sub iota)/2pi] at iota = 1000. Systematic errors are negligible compared to the (modest) level of foreground emission. Our best estimate of the power spectrum is derived from 28 cross-power spectra of statistically independent channels. The final spectrum is essentially independent of the noise properties of an individual radiometer. The resulting spectrum provides a definitive measurement of the CMB power spectrum, with uncertainties limited by cosmic variance, up to iota approximately 350. The spectrum clearly exhibits a first acoustic peak at iota = 220 and a second acoustic peak at iota approximately 540, and it provides strong support for adiabatic initial conditions. Researchers have analyzed the CT(sup Epsilon) power spectrum, and present evidence for a relatively high optical depth, and an early period of cosmic reionization. Among other things, this implies that the temperature power spectrum has been suppressed by approximately 30% on degree angular scales, due to secondary scattering.

Approximate l-fold cross-validation with Least Squares SVM and Kernel Ridge Regression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, Richard E; Zhang, Hao; Parker, Lynne Edwards

2013-01-01

Kernel methods have difficulties scaling to large modern data sets. The scalability issues are based on computational and memory requirements for working with a large matrix. These requirements have been addressed over the years by using low-rank kernel approximations or by improving the solvers scalability. However, Least Squares Support VectorMachines (LS-SVM), a popular SVM variant, and Kernel Ridge Regression still have several scalability issues. In particular, the O(n^3) computational complexity for solving a single model, and the overall computational complexity associated with tuning hyperparameters are still major problems. We address these problems by introducing an O(n log n) approximate l-foldmore » cross-validation method that uses a multi-level circulant matrix to approximate the kernel. In addition, we prove our algorithm s computational complexity and present empirical runtimes on data sets with approximately 1 million data points. We also validate our approximate method s effectiveness at selecting hyperparameters on real world and standard benchmark data sets. Lastly, we provide experimental results on using a multi-level circulant kernel approximation to solve LS-SVM problems with hyperparameters selected using our method.« less

Meltwater channel scars and the extent of Mid-Pleistocene glaciation in central Pennsylvania

NASA Astrophysics Data System (ADS)

Marsh, Ben

2017-10-01

High-resolution digital topographic data permit morphological analyses of glacial processes in detail that was previously infeasible. High-level glaciofluvial erosional scars in central Pennsylvania, identified and delimited using LiDAR data, define the approximate ice depth during a pre-Wisconsin advance, > 770,000 BP, on a landscape unaffected by Wisconsin glaciation. Distinctive scars on the prows of anticlinal ridges at 175-350 m above the valley floor locate the levels of subice meltwater channels. A two-component planar GIS model of the ice surface is derived using these features and intersected with a digital model of contemporary topography to create a glacial limit map. The map is compared to published maps, demonstrating the limits of conventional sediment-based mapping. Additional distinctive meltwater features that were cut during deglaciation are modeled in a similar fashion.

On neutron-gamma mixed field dosimetry with LiF:Mg,Ti at radiation protection dose levels.

PubMed

Weinstein, M; German, U; Alfassi, Z B

2006-01-01

The possibility of using the specific responses of the high temperature Peaks 6 and 7 and Peaks 4 and 5 to different LET radiations was mentioned in the past mainly for very high doses. The applicability of the two regions method for thermal neutrons--gamma ray mixed field dosimetry was investigated by analysing the response of LiF:Mg,Ti dosemeters irradiated to different ratios of thermal neutrons and gamma rays at radiation protection dose levels encountered in routine work conditions, up to approximately 50 mSv. The Region of Interest method was used to define the areas of the Peaks 4 + 5 and 6 + 7. We found that a simple algorithm can be used to determine with good accuracy the separate contributions of neutron and gamma doses.

Trajectories for High Specific Impulse High Specific Power Deep Space Exploration

NASA Technical Reports Server (NTRS)

Polsgrove, T.; Adams, R. B.; Brady, Hugh J. (Technical Monitor)

2002-01-01

Preliminary results are presented for two methods to approximate the mission performance of high specific impulse high specific power vehicles. The first method is based on an analytical approximation derived by Williams and Shepherd and can be used to approximate mission performance to outer planets and interstellar space. The second method is based on a parametric analysis of trajectories created using the well known trajectory optimization code, VARITOP. This parametric analysis allows the reader to approximate payload ratios and optimal power requirements for both one-way and round-trip missions. While this second method only addresses missions to and from Jupiter, future work will encompass all of the outer planet destinations and some interstellar precursor missions.

Study to evaluate the effect of low-intensity pulsed electrical currents on levels of oedema in chronic non-healing wounds.

PubMed

Young, S; Hampton, S; Tadej, M

2011-08-01

To evaluate the efficacy of a medical device, Accel-Heal, which generates a low-intensity pulsed direct current, on the management of oedema in chronic leg ulcers, using high-frequency diagnostic ultrasound. High-frequency diagnostic ultrasound (20MHz) with an axial resolution of 60um was used to assess the effect of an electrical stimulation device delivering a low-intensity pulsed current on levels of oedema in chronic non-healing venous and mixed aetiology leg ulcers for a period of 10 days. Thirty patients' wounds were monitored over a 3-month period, during which time changes in levels of oedema in the wound bed and surrounding tissues were imaged and measured. A significant fall in the, previously high level, of periwound oedema was noted in the patient population after 10 days of device application. By 20 days after the first application of the device the level of periwound oedema had decreased by approximately 60% of the original level, which was maintained up to the 90-day follow-up. Occurring in parallel with this, scans of the wound bed showed a rapid decrease in the levels of oedema as the new wound matrix was laid down. The electrical stimulation device appeared to be effective in reducing oedema levels in a range of chronic wounds and their surrounding tissues. The study was funded by a grant from Synapse micro-current Ltd.

Thematic Accuracy Assessment of the 2011 National Land ...

EPA Pesticide Factsheets

Accuracy assessment is a standard protocol of National Land Cover Database (NLCD) mapping. Here we report agreement statistics between map and reference labels for NLCD 2011, which includes land cover for ca. 2001, ca. 2006, and ca. 2011. The two main objectives were assessment of agreement between map and reference labels for the three, single-date NLCD land cover products at Level II and Level I of the classification hierarchy, and agreement for 17 land cover change reporting themes based on Level I classes (e.g., forest loss; forest gain; forest, no change) for three change periods (2001–2006, 2006–2011, and 2001–2011). The single-date overall accuracies were 82%, 83%, and 83% at Level II and 88%, 89%, and 89% at Level I for 2011, 2006, and 2001, respectively. Many class-specific user's accuracies met or exceeded a previously established nominal accuracy benchmark of 85%. Overall accuracies for 2006 and 2001 land cover components of NLCD 2011 were approximately 4% higher (at Level II and Level I) than the overall accuracies for the same components of NLCD 2006. The high Level I overall, user's, and producer's accuracies for the single-date eras in NLCD 2011 did not translate into high class-specific user's and producer's accuracies for many of the 17 change reporting themes. User's accuracies were high for the no change reporting themes, commonly exceeding 85%, but were typically much lower for the reporting themes that represented change. Only forest l

Advanced Materials and Component Development for Lithium-Ion Cells for NASA Missions

NASA Technical Reports Server (NTRS)

Reid, Concha M.

2012-01-01

Human missions to Near Earth Objects, such as asteroids, planets, moons, liberation points, and orbiting structures, will require safe, high specific energy, high energy density batteries to provide new or extended capabilities than are possible with today s state-of-the-art aerospace batteries. The Enabling Technology Development and Demonstration Program, High Efficiency Space Power Systems Project battery development effort at the National Aeronautics and Space Administration (NASA) is continuing advanced lithium-ion cell development efforts begun under the Exploration Technology Development Program Energy Storage Project. Advanced, high-performing materials are required to provide improved performance at the component-level that contributes to performance at the integrated cell level in order to meet the performance goals for NASA s High Energy and Ultra High Energy cells. NASA s overall approach to advanced cell development and interim progress on materials performance for the High Energy and Ultra High Energy cells after approximately 1 year of development has been summarized in a previous paper. This paper will provide an update on these materials through the completion of 2 years of development. The progress of materials development, remaining challenges, and an outlook for the future of these materials in near term cell products will be discussed.

Catch-Disperse-Release Readout for Superconducting Qubits

DTIC Science & Technology

2013-03-01

adiabatic, a fast high-fidelity qubit readout is possible even in the strongly nonlinear dispersive regime. Interestingly, the Jaynes - Cummings nonlinearity...will be included later) and describe the system by the Jaynes - Cummings (JC) Hamiltonian [7] with a microwave drive (we use ~ = 1) H = ωq(t)σ+σ− + ωra...λeff,0 rotates on the phase plane faster than in the two-level approximation , while λeff,1 rotates slower (some- times even in the opposite

Experimental Investigation of Hydrodynamic Self-Acting Gas Bearings at High Knudsen Numbers.

DTIC Science & Technology

1980-07-01

Reynolds equation. Two finite - difference algorithms were used to solve the equation. Numerical results - the predicted load and pitch angle - from the two...that should be used. The majority of the numerical solution are still based on the finite difference approximation of the governing equation. But in... finite difference method. Reddi and Chu [26) also noted that it is very difficult to compare the two techniques on the same level since the solution

Influence of Γ-X band mixing on the excited donor in a parabolic quantum well

NASA Astrophysics Data System (ADS)

Raghuvaran, T.; Shanthi, R. Vijaya; D'Reuben, A. Merwyn Jasper; Nithiananthi, P.

2013-06-01

Equally spaced energy levels of Parabolic Quantum Well are perturbed due to the application of hydrostatic pressure. It will modify the electronic and optical behavior of high Potential devices. The variation of excited state donor binding energy due to Γ-X band mixing at critical cross over pressures in a Parabolic GaAs/AlxGa1-x As quantum well has been investigated in the effective mass approximation using variational method.

Interventions with potential to improve the mental health and wellbeing of UK veterinary surgeons.

PubMed

Bartram, D J; Sinclair, J M A; Baldwin, D S

2010-04-24

The proportion of UK veterinary surgeons who die by suicide as opposed to other causes is approximately four times that of the general population, and around twice that of other healthcare professionals. Recent research suggests that veterinary surgeons report high levels of psychological distress. This paper proposes a portfolio of evidence-based interventions, for both organisations and individuals, which have the potential to improve mental health and wellbeing in the veterinary profession.

Association/Dissociation Processes in Dense Gases.

DTIC Science & Technology

1985-08-16

temperature 0 and generally lies 1 0 ke below the dissociation limit (taken as zero energy). The central block E of highly excited " bound levels is...approximate solution of (1.1) with general V(R) "* a large body of literature (see ref. 7) exists on various schemes based on Green’s function,8...be obtained for general mass systems provided the new basic expression introduced here - for RAD(t) is adopted. A The microscopic basis of the

Processes of energy deposition by heavy-particle and electron impact. Final progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salop, A.; Smith, F.T.

1978-04-18

Progress is reported in three areas of reasearch during the present period: K-shell ionization in high energy collisions of heavy ions with light target atoms using the sudden (Magnus) approximation, K-L level matching phenomena associated with K-shell vacancy production in heavy-ion collisions, and studies of low energy collisions of electrons with molecules using semi-classical perturbation theory. A brief discussion of each of these activities is given.

Adding Automation and Decision Support Capabilities at the Reagan Test Site

DTIC Science & Technology

2016-04-04

Tech Notes www.ll.mit.edu May 2016 The U.S. Army’s Reagan Test Site (RTS), approximately 2300 miles west southwest of Hawaii on the Kwajalein Atoll...in the Marshall Islands , is ideal for missile and interceptor testing because of its distance from populous areas and its open-ocean line from...by three components: • The event processor determines the high-level state of the mission by moni- toring events such as information from uprange

Low Earth orbital atomic oxygen environmental simulation facility for space materials evaluation

NASA Technical Reports Server (NTRS)

Stidham, Curtis R.; Banks, Bruce A.; Stueber, Thomas J.; Dever, Joyce A.; Rutledge, Sharon K.; Bruckner, Eric J.

1993-01-01

Simulation of low Earth orbit atomic oxygen for accelerated exposure in ground-based facilities is necessary for the durability evaluation of space power system component materials for Space Station Freedom (SSF) and future missions. A facility developed at the National Aeronautics and Space Administrations's (NASA) Lewis Research Center provides accelerated rates of exposure to a directed or scattered oxygen beam, vacuum ultraviolet (VUV) radiation, and offers in-situ optical characterization. The facility utilizes an electron-cyclotron resonance (ECR) plasma source to generate a low energy oxygen beam. Total hemispherical spectral reflectance of samples can be measured in situ over the wavelength range of 250 to 2500 nm. Deuterium lamps provide VUV radiation intensity levels in the 115 to 200 nm range of three to five equivalent suns. Retarding potential analyses show distributed ion energies below 30 electron volts (eV) for the operating conditions most suited for high flux, low energy testing. Peak ion energies are below the sputter threshold energy (approximately 30 eV) of the protective coatings on polymers that are evaluated in the facility, thus allowing long duration exposure without sputter erosion. Neutral species are expected to be at thermal energies of approximately .04 eV to .1 eV. The maximum effective flux level based on polyimide Kapton mass loss is 4.4 x 10 exp 6 atoms/((sq. cm)*s), thus providing a highly accelerated testing capability.

Are Early-Life Socioeconomic Conditions Directly Related to Birth Outcomes? Grandmaternal Education, Grandchild Birth Weight, and Associated Bias Analyses

PubMed Central

Huang, Jonathan Y.; Gavin, Amelia R.; Richardson, Thomas S.; Rowhani-Rahbar, Ali; Siscovick, David S.; Enquobahrie, Daniel A.

2015-01-01

Grandmaternal education may be related to grandchild birth weight (GBW) through maternal early-life development; however, conventional regression models may be endogenously confounded. Alternative models employing explicit structural assumptions may provide incrementally clearer evidence. We used data from the US National Longitudinal Study of Adolescent to Adult Health (1995–2009; 1,681 mother-child pairs) to estimate “direct effects” of grandmaternal educational level (less than high school, high school diploma or equivalent, or college degree) at the time of the mother's birth on GBW, adjusted for maternal life-course factors: maltreatment as a child, education and income as an adult, prepregnancy overweight, and prenatal smoking. Using conventional and marginal structural model (MSM) approaches, we estimated 54-g (95% confidence interval: −14.0, 122.1) and 87-g (95% confidence interval: 10.9, 162.5) higher GBWs per increase in educational level, respectively. The MSM allowed simultaneous mediation by and adjustment for prepregnancy overweight. Estimates were insensitive to alternate structural assumptions and mediator parameterizations. Bias analysis suggested that a single unmeasured confounder would have to have a strong influence on GBW (approximately 150 g) or be greatly imbalanced across exposure groups (approximately 25%) to completely explain the findings. Coupling an MSM with sensitivity analyses provides some evidence that maternal early-life socioeconomic environment is directly associated with offspring birth weight. PMID:26283086

Evaluation of Dicyphus hersperus (Heteroptera: Miridae) for biological control of Frankliniella occidentalis (Thysanoptera: Thripidae) on greenhouse tomato.

PubMed

Shipp, J L; Wang, K

2006-04-01

The effectiveness of inoculative releases of the mirid predator Dicyphus hesperus Knight for control of Frankliniella occidentalis (Pergande) on greenhouse tomatoes was evaluated in terms of suppression of the population densities of F. occidentalis and associated fruit damage in the presence of the predator over two seasonal trials. An inoculative release of one D. hesperus per plant (approximately 0.1:10 predator:prey ratio) at a high F. occidentalis population density (140 thrips per plant) suppressed the thrips population density to a significantly lower level, compared with the nonrelease greenhouse, but not below a thrips level that caused economic fruit damage. As the predator:prey ratio increased to approximately 0.5:10 D. hesperus:F. occidentalis, the mean percentage of the thrips-damaged fruit in the D. hesperus release greenhouse decreased to 1.6%. However, the amount of fruit feeding by D. hesperus was highly correlated to the availability of prey (or predator:prey ratio) under greenhouse conditions. D. hesperus-induced fruit damage occurred when the predator:prey ratio was >1:10 D. hesperus:F. occidentalis. Considering the potential risk of fruit damage by D. hesperus and the need for effective control of F. occidentalis, a 0.5-1:10 D. hesperus:F. occidentalis ratio is recommended when the thrips population density is in the range of 60-150 thrips per plant.

PBDEs, PBBs, and PCNs in three communities of free-ranging killer whales (Orcinus orca) from the northeastern Pacific Ocean.

PubMed

Rayne, Sierra; Ikonomou, Michael G; Ross, Peter S; Ellis, Graeme M; Barrett-Lennard, Lance G

2004-08-15

Polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), and polychlorinated naphthalenes (PCNs) were quantified in blubber biopsy samples collected from free-ranging male and female killer whales (Orcinus orca) belonging to three distinct communities (southern residents, northern residents, and transients) from the northeastern Pacific Ocean. High concentrations of sigmaPBDE were observed in male southern residents (942+/-582 ng/g Iw), male and female transients (1015+/-605 and 885+/-706 ng/g Iw, respectively), and male and female northern residents (203+/-116 and 415+/-676 ng/g Iw, respectively). Because of large variation within sample groups, sigmaPBDE levels generally did not differ statistically with the exception of male northern residents, which had lower sigmaPBDE concentrations than male southern residents, male transients, and female transients, perhaps reflecting the consumption of less contaminated prey items. Male transient killer whales, which consume high trophic level prey including other cetaceans and occasionally spend time near populated areas, had sigmaPBDE concentrations approximately equal to southern residents. No significant age-related relationships were observed for sigmaPBDE concentrations. sigmaPBDE concentrations were approximately 1-3 orders of magnitude greater than those of sigmaPBB (3.0-31 ng/g Iw) and sigmaPCN (20-167 ng/g Iw) measured in a subset of samples, suggesting that PBDEs may represent a contaminant class of concern in these marine mammals.

Interactive diversity promotes the evolution of cooperation in structured populations

NASA Astrophysics Data System (ADS)

Su, Qi; Li, Aming; Zhou, Lei; Wang, Long

2016-10-01

Evolutionary games on networks traditionally assume that each individual adopts an identical strategy to interact with all its neighbors in each generation. Considering the prevalent diversity of individual interactions in the real society, here we propose the concept of interactive diversity, which allows individuals to adopt different strategies against different neighbors in each generation. We investigate the evolution of cooperation based on the edge dynamics rather than the traditional nodal dynamics in networked systems. The results show that, without invoking any other mechanisms, interactive diversity drives the frequency of cooperation to a high level for a wide range of parameters in both well-mixed and structured populations. Even in highly connected populations, cooperation still thrives. When interactive diversity and large topological heterogeneity are combined together, however, in the relaxed social dilemma, cooperation level is lower than that with just one of them, implying that the combination of many promotive factors may make a worse outcome. By an analytical approximation, we get the condition under which interactive diversity provides more advantages for cooperation than traditional evolutionary dynamics does. Numerical simulations validating the approximation are also presented. Our work provides a new line to explore the latent relation between the ubiquitous cooperation and individuals’ distinct responses in different interactions. The presented results suggest that interactive diversity should receive more attention in pursuing mechanisms fostering cooperation.

Potentiometric surface map of the Floridan Aquifer in the St Johns River Water Management District and vicinity, Florida, September, 1977

USGS Publications Warehouse

Watkins, F.A.; Laughlin, C.P.; Hayes, E.C.

1977-01-01

This map presents the potentiometric surface of the Floridan aquifer in the St. Johns River Water Management District and vicinity for September 1977. The Floridan aquifer is the principal source of potable water in the area. Water-level measurements were made on approximately 900 wells and springs. The potentiometric surface is shown by 5-foot contours except in the Fernandina Beach area where 10- and 20-foot contours are used to show the deep cone of depression. This is the first map covering the entire St. Johns River Water Management District and vicinity for September, a high water-level period. The potentiometric surface ranged from 130 feet above mean sea level in Polk County to 131 feet below sea level in Nassau County. (Woodard-USGS)

Sea-level projections representing the deeply uncertain contribution of the West Antarctic ice sheet.

PubMed

Bakker, Alexander M R; Wong, Tony E; Ruckert, Kelsey L; Keller, Klaus

2017-06-20

There is a growing awareness that uncertainties surrounding future sea-level projections may be much larger than typically perceived. Recently published projections appear widely divergent and highly sensitive to non-trivial model choices . Moreover, the West Antarctic ice sheet (WAIS) may be much less stable than previous believed, enabling a rapid disintegration. Here, we present a set of probabilistic sea-level projections that approximates the deeply uncertain WAIS contributions. The projections aim to inform robust decisions by clarifying the sensitivity to non-trivial or controversial assumptions. We show that the deeply uncertain WAIS contribution can dominate other uncertainties within decades. These deep uncertainties call for the development of robust adaptive strategies. These decision-making needs, in turn, require mission-oriented basic science, for example about potential signposts and the maximum rate of WAIS-induced sea-level changes.

Hypercalcaemia secondary to hypervitaminosis a in a patient with chronic renal failure.

PubMed

Hammoud, D; El Haddad, B; Abdallah, J

2014-01-01

Vitamin A toxicity is a well-described medical condition with a multitude of potential presenting signs and symptoms. It can be divided into acute and chronic toxicity. Serum vitamin A concentrations are raised in chronic renal failure even with ingestion of less than the usual toxic doses. Hypercalcaemia can occasionally be associated with high levels of vitamin A but it is rare. In this report, we describe a 67- year old female patient with chronic kidney disease who was taking vitamin A supplements for approximately 10 years. The patient had worsening of her chronic kidney disease over the last years and developed chronic hypercalcaemia. Her vitamin A level was elevated with a daily intake of 7000 IU. The vitamin A supplement was stopped. A few months later, vitamin A level diminished substantially and serum calcium levels returned to normal.

Attitude of Israeli mothers with vaccination of their daughters against human papilloma virus.

PubMed

Ben Natan, Merav; Aharon, Osnat; Palickshvili, Sharon; Gurman, Vicky

2011-02-01

The purpose of the study is to examine whether the model based on the Theory of Reasoned Action (TRA) succeeds in predicting mothers' intention to vaccinate their daughters against the human papilloma virus infection. Questionnaires were distributed among convenience sample of 103 mothers of daughters 18 years and younger. Approximately 65% of mothers intend to vaccinate their daughters. Behavioral beliefs, normative beliefs, and level of knowledge had a significant positive effect on mothers' intention to vaccinate their daughters. High levels of religiosity were found to negatively affect mothers' intention to vaccinate their daughters. The TRA combined with level of knowledge and level of religiosity succeeds in predicting mothers' behavioral intentions regarding vaccinating daughters. This indicates the significance of nurses' roles in imparting information and increasing awareness among mothers. Copyright © 2011. Published by Elsevier Inc.

Immunoglobulins in bovine mammary secretions

PubMed Central

Porter, P.

1972-01-01

Antibodies against Escherichia coli 08 in bovine colostrum and serum have been studied by gel filtration chromatography and the red cell linked antigen—antiglobulin reaction. Immunoglobulins were assayed by radial immunodiffusion. In bovine colostrum anti-E. coli activity was attributable to IgA and the level of activity was comparable with that detected in IgM and IgG fractions. The immunoglobulin profile and distribution of E. coli antibodies in post-colostral calf serum was similar to that in colostrum, thus providing an unusual occurrence of high levels of secretory IgA in serum. However the immunoglobulin disappeared rapidly from the serum with an apparent half life of approximately 2 days; the value for IgM was 4 days. During the first 3 days of lactation the levels of immunoglobulins fall rapidly and milk is subsequently secreted with uniformly low levels of antibodies. PMID:4560742

Food security among individuals experiencing homelessness and mental illness in the At Home/Chez Soi Trial.

PubMed

O'Campo, Patricia; Hwang, Stephen W; Gozdzik, Agnes; Schuler, Andrée; Kaufman-Shriqui, Vered; Poremski, Daniel; Lazgare, Luis Ivan Palma; Distasio, Jino; Belbraouet, Slimane; Addorisio, Sindi

2017-08-01

Individuals experiencing homelessness are particularly vulnerable to food insecurity. The At Home/Chez Soi study provides a unique opportunity to first examine baseline levels of food security among homeless individuals with mental illness and second to evaluate the effect of a Housing First (HF) intervention on food security in this population. At Home/Chez Soi was a 2-year randomized controlled trial comparing the effectiveness of HF compared with usual care among homeless adults with mental illness, stratified by level of need for mental health services (high or moderate). Logistic regressions tested baseline associations between food security (US Food Security Survey Module), study site, sociodemographic variables, duration of homelessness, alcohol/substance use, physical health and service utilization. Negative binomial regression determined the impact of the HF intervention on achieving levels of high or marginal food security over an 18-month follow-up period (6 to 24 months). Community settings at five Canadian sites (Moncton, Montreal, Toronto, Winnipeg and Vancouver). Homeless adults with mental illness (n 2148). Approximately 41 % of our sample reported high or marginal food security at baseline, but this figure varied with gender, age, mental health issues and substance use problems. High need participants who received HF were more likely to achieve marginal or high food security than those receiving usual care, but only at the Toronto and Moncton sites. Our large multi-site study demonstrated low levels of food security among homeless experiencing mental illness. HF showed promise for improving food security among participants with high levels of need for mental health services, with notable site differences.

Assessment of microbiological quality of drinking water from household tanks in Bermuda.

PubMed

Lévesque, B; Pereg, D; Watkinson, E; Maguire, J S; Bissonnette, L; Gingras, S; Rouja, P; Bergeron, M G; Dewailly, E

2008-06-01

Bermuda residents collect rainwater from rooftops to fulfil their freshwater needs. The objective of this study was to assess the microbiological quality of drinking water in household tanks throughout Bermuda. The tanks surveyed were selected randomly from the electoral register. Governmental officers visited the selected household (n = 102) to collect water samples and administer a short questionnaire about the tank characteristics, the residents' habits in terms of water use, and general information on the water collecting system and its maintenance. At the same time, water samples were collected for analysis and total coliforms and Escherichia coli were determined by 2 methods (membrane filtration and culture on chromogenic media, Colilert kit). Results from the 2 methods were highly correlated and showed that approximately 90% of the samples analysed were contaminated with total coliforms in concentrations exceeding 10 CFU/100 mL, and approximately 66% of samples showed contamination with E. coli. Tank cleaning in the year prior to sampling seems to protect against water contamination. If rainwater collection from roofs is the most efficient mean for providing freshwater to Bermudians, it must not be considered a source of high quality drinking water because of the high levels of microbial contamination.

The NASA Advanced Space Power Systems Project

NASA Technical Reports Server (NTRS)

Mercer, Carolyn R.; Hoberecht, Mark A.; Bennett, William R.; Lvovich, Vadim F.; Bugga, Ratnakumar

2015-01-01

The goal of the NASA Advanced Space Power Systems Project is to develop advanced, game changing technologies that will provide future NASA space exploration missions with safe, reliable, light weight and compact power generation and energy storage systems. The development effort is focused on maturing the technologies from a technology readiness level of approximately 23 to approximately 56 as defined in the NASA Procedural Requirement 7123.1B. Currently, the project is working on two critical technology areas: High specific energy batteries, and regenerative fuel cell systems with passive fluid management. Examples of target applications for these technologies are: extending the duration of extravehicular activities (EVA) with high specific energy and energy density batteries; providing reliable, long-life power for rovers with passive fuel cell and regenerative fuel cell systems that enable reduced system complexity. Recent results from the high energy battery and regenerative fuel cell technology development efforts will be presented. The technical approach, the key performance parameters and the technical results achieved to date in each of these new elements will be included. The Advanced Space Power Systems Project is part of the Game Changing Development Program under NASAs Space Technology Mission Directorate.

Materials and noncoplanar mesh designs for integrated circuits with linear elastic responses to extreme mechanical deformations.

PubMed

Kim, Dae-Hyeong; Song, Jizhou; Choi, Won Mook; Kim, Hoon-Sik; Kim, Rak-Hwan; Liu, Zhuangjian; Huang, Yonggang Y; Hwang, Keh-Chih; Zhang, Yong-wei; Rogers, John A

2008-12-02

Electronic systems that offer elastic mechanical responses to high-strain deformations are of growing interest because of their ability to enable new biomedical devices and other applications whose requirements are impossible to satisfy with conventional wafer-based technologies or even with those that offer simple bendability. This article introduces materials and mechanical design strategies for classes of electronic circuits that offer extremely high stretchability, enabling them to accommodate even demanding configurations such as corkscrew twists with tight pitch (e.g., 90 degrees in approximately 1 cm) and linear stretching to "rubber-band" levels of strain (e.g., up to approximately 140%). The use of single crystalline silicon nanomaterials for the semiconductor provides performance in stretchable complementary metal-oxide-semiconductor (CMOS) integrated circuits approaching that of conventional devices with comparable feature sizes formed on silicon wafers. Comprehensive theoretical studies of the mechanics reveal the way in which the structural designs enable these extreme mechanical properties without fracturing the intrinsically brittle active materials or even inducing significant changes in their electrical properties. The results, as demonstrated through electrical measurements of arrays of transistors, CMOS inverters, ring oscillators, and differential amplifiers, suggest a valuable route to high-performance stretchable electronics.

Genetic variation in lipoprotein (a) levels in families enriched for coronary artery disease is determined almost entirely by the apolipoprotein (a) gene locus.

PubMed Central

DeMeester, C A; Bu, X; Gray, R J; Lusis, A J; Rotter, J I

1995-01-01

Lipoprotein (a) (Lp[a]) is a cholesterol-rich lipoprotein resembling LDL but also containing a large polypeptide designated apolipoprotein (a) (apo[a]). Its levels are highly variable among individuals and, in a number of studies, are strongly correlated with the risk of coronary artery disease (CAD). In an effort to determine which genes control Lp(a) levels, we have studied 25 multiplex families (comprising 298 members) enriched for CAD. The apo(a) gene was genotyped among the families, using a highly informative pulse-field gel electrophoresis procedure. In addition, polymorphisms of the gene for the other major protein of Lp(a), apolipoprotein B (apoB), were examined. Quantitative sib-pair linkage analysis indicates that apo(a) is the major gene controlling Lp(a) levels in this CAD population (P = .001; 99 sib pairs), whereas the apoB gene demonstrated no significant quantitative linkage effect. We estimate that the apo(a) locus accounts for < or = 98% of variance of Lp(a) serum levels. Approximately 43% of this variation is explained by size polymorphisms within the apo(a) gene. These results indicate that the apo(a) gene is the major determinant of Lp(a) serum levels not only in the general population but also in a high-risk CAD population. Images Figure 2 PMID:7825589

Readability of websites containing information about prostate cancer treatment options.

PubMed

Ellimoottil, Chandy; Polcari, Anthony; Kadlec, Adam; Gupta, Gopal

2012-12-01

Approximately 90 million American adults have literacy skills that test below a high school reading level. Websites written above this level can pose a challenge for those seeking online information about prostate cancer treatment options. In this study we determine the readability of selected websites using a systematic search process and validated readability formulas. We identified the 3 most popular keywords from 513 terms related to prostate cancer treatment options. We then systematically collected 270 websites from the top 3 search engines, and excluded from study those that were nonEnglish, not primarily text, irrelevant and/or duplicated. We used the Flesch-Kincaid grade level and Flesch Reading Ease to determine scores for each site. A total of 62 unique websites were analyzed. Median Flesch-Kincaid grade level was 12.0 (range 8.0 to 12.0) and median Flesch Reading Ease score was 38.1 (range 0.0 to 65.5). Only 3 sites (4.8%) were written below a high school reading level (less than 9.0). Few websites with discussions on prostate cancer treatment options are written below a high school reading level. This is problematic for a third of Americans who seek to further educate themselves using online resources. Clinicians can use this information to guide their patients to appropriate websites. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Cross-reactivity of Schistosoma mansoni-Fasciola gigantica influenced by saponins.

PubMed

Maghraby, Amany Sayed; Shaker, Kamel H; Gaber, Hanaa M

2009-01-01

The aim of the present work was to investigate the Schistosoma mansoni and Fasciola gigantica cross-reactivity between adult worms and egg homogenates of the parasites. Immunoprophylactic effects of crude Schistosoma mansoni worms and egg antigens mixed with or without saponins extracted from Atriplex nummularia were studied followed by challenge with 80 cercariae of Schistosoma mansoni. Our results showed that post 1st immunization with schistosome egg antigens (SEA) there was a significant change (P approximately 0.05) in the IgM levels against Fasciola egg homogenate (FgEH) without saponins. Post 2nd immunization with SEA mixed with saponins the levels of IgM increased significantly (P approximately 0.05) against Fasciola worm homogenate (FgWH) as compared with a non-immunized group. Post 2nd immunization the level of IgG was significantly elevated (P approximately 0.05) by SEA mixed with saponins against FgWH. Post 2nd immunizations with SEA mixed with saponins showed a significant change (P approximately 0.05) in IgG levels against FgEH. These results clearly demonstrated that there is a cross-reactivity between Schistosoma mansoni eggs and Fasciola gigantica worms and eggs. Saponins were found to be immunostimulatory adjuvants in our study.

Reduction of verotoxigenic Escherichia coli by process and recipe optimisation in dry-fermented sausages.

PubMed

Heir, E; Holck, A L; Omer, M K; Alvseike, O; Høy, M; Måge, I; Axelsson, L

2010-07-15

Outbreaks of verotoxigenic Escherichia coli (VTEC) linked to dry-fermented sausages (DFSs) have emphasized the need for DFS manufacturers to introduce measures to obtain enhanced safety and still maintain the sensory qualities of their products. To our knowledge no data have yet been reported on non-O157:H7 VTEC survival in DFS. Here, the importance of recipe and process variables on VTEC (O157:H7 and O103:H25) reductions in two types of DFS, morr and salami, was determined through three statistically designed experiments. Linear regression and ANOVA analyses showed that no single variable had a dominant effect on VTEC reductions. High levels of NaCl, NaNO(2), glucose (low pH) and fermentation temperature gave enhanced VTEC reduction, while high fat and large casing diameter (a(w)) gave the opposite effect. Interaction effects were small. The process and recipe variables showed similar effects in morr and salami. In general, recipes combining high batter levels of salt (NaCl and NaNO(2)) and glucose along with high fermentation temperature that gave DFS with low final pH and a(w), provided approximately 3 log(10) reductions compared to approximately 1.5 log(10) reductions obtained for standard recipe DFS. Storage at 4 degrees C for 2 months provided log(10) 0.33-0.95 additional VTEC reductions and were only marginally affected by recipe type. Sensory tests revealed only small differences between the various recipes of morr and salami. By optimisation of recipe and process parameters, it is possible to obtain increased microbial safety of DFS while maintaining the sensory qualities of the sausages. 2010 Elsevier B.V. All rights reserved.

Risk profiling of cattle farms as a potential tool in risk-based surveillance for Mycobacterium bovis infection among cattle in tuberculosis-free areas.

PubMed

Ribeiro-Lima, Joao; Schwabenlander, Stacey; Oakes, Michael; Thompson, Beth; Wells, Scott J

2016-06-15

OBJECTIVE To develop a cattle herd risk-profiling system that could potentially inform risk-based surveillance strategies for Mycobacterium bovis infection in cattle and provide information that could be used to help direct resource allocation by a state agency for this purpose. DESIGN Cross-sectional study. SAMPLE Records for any size movement (importation) of cattle into Minnesota from other US states during 2009 (n = 7,185) and 2011 (8,107). PROCEDURES Data from certificates of veterinary inspection were entered into a spreadsheet. Movement data were summarized at premises and county levels, and for each level, the distribution of cattle moved and number of movements were evaluated. Risk profiling (assessment and categorization of risk for disease introduction) for each import movement was performed on the basis of known risk factors. Latent class analysis was used to assign movements to risk classifications with adjustment on the basis of expert opinions from personnel knowledgeable about bovine tuberculosis; these data were used to classify premises as very high, high, medium, or low risk for disease introduction. RESULTS In each year, approximately 1,500 premises imported cattle, typically beef and feeder types, with the peak of import movements during the fall season. The risk model identified 4 risk classes for cattle movements. Approximately 500 of the estimated 27,406 (2%) cattle premises in Minnesota were in the very high or high risk groups for either year; greatest density of these premises was in the southeast and southwest regions of the state. CONCLUSIONS AND CLINICAL RELEVANCE A risk-profiling approach was developed that can be applied in targeted surveillance efforts for bovine tuberculosis, particularly in disease-free areas.

Approximate number word knowledge before the cardinal principle.

PubMed

Gunderson, Elizabeth A; Spaepen, Elizabet; Levine, Susan C

2015-02-01

Approximate number word knowledge-understanding the relation between the count words and the approximate magnitudes of sets-is a critical piece of knowledge that predicts later math achievement. However, researchers disagree about when children first show evidence of approximate number word knowledge-before, or only after, they have learned the cardinal principle. In two studies, children who had not yet learned the cardinal principle (subset-knowers) produced sets in response to number words (verbal comprehension task) and produced number words in response to set sizes (verbal production task). As evidence of approximate number word knowledge, we examined whether children's numerical responses increased with increasing numerosity of the stimulus. In Study 1, subset-knowers (ages 3.0-4.2 years) showed approximate number word knowledge above their knower-level on both tasks, but this effect did not extend to numbers above 4. In Study 2, we collected data from a broader age range of subset-knowers (ages 3.1-5.6 years). In this sample, children showed approximate number word knowledge on the verbal production task even when only examining set sizes above 4. Across studies, children's age predicted approximate number word knowledge (above 4) on the verbal production task when controlling for their knower-level, study (1 or 2), and parents' education, none of which predicted approximation ability. Thus, children can develop approximate knowledge of number words up to 10 before learning the cardinal principle. Furthermore, approximate number word knowledge increases with age and might not be closely related to the development of exact number word knowledge. Copyright © 2014 Elsevier Inc. All rights reserved.

Multivariate moment closure techniques for stochastic kinetic models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lakatos, Eszter, E-mail: e.lakatos13@imperial.ac.uk; Ale, Angelique; Kirk, Paul D. W.

2015-09-07

Stochastic effects dominate many chemical and biochemical processes. Their analysis, however, can be computationally prohibitively expensive and a range of approximation schemes have been proposed to lighten the computational burden. These, notably the increasingly popular linear noise approximation and the more general moment expansion methods, perform well for many dynamical regimes, especially linear systems. At higher levels of nonlinearity, it comes to an interplay between the nonlinearities and the stochastic dynamics, which is much harder to capture correctly by such approximations to the true stochastic processes. Moment-closure approaches promise to address this problem by capturing higher-order terms of the temporallymore » evolving probability distribution. Here, we develop a set of multivariate moment-closures that allows us to describe the stochastic dynamics of nonlinear systems. Multivariate closure captures the way that correlations between different molecular species, induced by the reaction dynamics, interact with stochastic effects. We use multivariate Gaussian, gamma, and lognormal closure and illustrate their use in the context of two models that have proved challenging to the previous attempts at approximating stochastic dynamics: oscillations in p53 and Hes1. In addition, we consider a larger system, Erk-mediated mitogen-activated protein kinases signalling, where conventional stochastic simulation approaches incur unacceptably high computational costs.« less

Fullerenes, fulleranes and polycyclic aromatic hydrocarbons in the Allende meteorite

NASA Technical Reports Server (NTRS)

Becker, L.; Bunch, T. E.

1997-01-01

In this paper, we confirm our earlier observations of fullerenes (C60 and C70) in the Allende meteorite (Becker et al., 1994a, 1995). Fullerene C60 was also detected in two separate C-rich (approximately 0.5-1.0%) dark inclusions (Heymann et al., 1987) that were hand picked from the Allende sample. The amounts of C60 detected were approximately 5 and approximately 10 ppb, respectively, which is considerably less than what was detected in the Allende 15/21 sample (approximately 100 ppb; Becker et al., 1994a, 1995). This suggests that fullerenes are heterogeneously distributed in the meteorite. In addition, we present evidence for fulleranes, (C60Hx), detected in separate samples by laser desorption (reflectron) time-of-flight (TOF) mass spectrometry (LDMS). The LDMS spectra for the Allende extracts were remarkably similar to the spectra generated for the synthetic fullerane mixtures. Several fullerane products were synthesized using a Rh catalyst (Becker et al., 1993a) and separated using high-performance liquid chromatography (HPLC). Polycyclic aromatic hydrocarbons (PAHs) were also observed ppm levels) that included benzofluoranthene and corannulene, a cup-shaped molecule that has been proposed as a precursor molecule to the formation of fullerenes in the gas phase (Pope et al., 1993).

Quantitative fundus autofluorescence in mice: correlation with HPLC quantitation of RPE lipofuscin and measurement of retina outer nuclear layer thickness.

PubMed

Sparrow, Janet R; Blonska, Anna; Flynn, Erin; Duncker, Tobias; Greenberg, Jonathan P; Secondi, Roberta; Ueda, Keiko; Delori, François C

2013-04-17

Our study was conducted to establish procedures and protocols for quantitative autofluorescence (qAF) measurements in mice, and to report changes in qAF, A2E bisretinoid concentration, and outer nuclear layer (ONL) thickness in mice of different genotypes and age. Fundus autofluorescence (AF) images (55° lens, 488 nm excitation) were acquired in albino Abca4(-/-), Abca4(+/-), and Abca4(+/+) mice (ages 2-12 months) with a confocal scanning laser ophthalmoscope (cSLO). Gray levels (GLs) in each image were calibrated to an internal fluorescence reference. The bisretinoid A2E was measured by quantitative high performance liquid chromatography (HPLC). Histometric analysis of ONL thicknesses was performed. The Bland-Altman coefficient of repeatability (95% confidence interval) was ±18% for between-session qAF measurements. Mean qAF values increased with age (2-12 months) in all groups of mice. qAF was approximately 2-fold higher in Abca4(-/-) mice than in Abca4(+/+) mice and approximately 20% higher in heterozygous mice. HPLC measurements of the lipofuscin fluorophore A2E also revealed age-associated increases, and the fold difference between Abca4(-/-) and wild-type mice was more pronounced (approximately 3-4-fold) than measurable by qAF. Moreover, A2E levels declined after 8 months of age, a change not observed with qAF. The decline in A2E levels in the Abca4(-/-) mice corresponded to reduced photoreceptor cell viability as reflected in ONL thinning beginning at 8 months of age. The qAF method enables measurement of in vivo lipofuscin and the detection of genotype and age-associated differences. The use of this approach has the potential to aid in understanding retinal disease processes and will facilitate preclinical studies.

Effect of cocaine on Fas-associated protein with death domain in the rat brain: individual differences in a model of differential vulnerability to drug abuse.

PubMed

García-Fuster, María-Julia; Clinton, Sarah M; Watson, Stanley J; Akil, Huda

2009-04-01

This study was designed to (1) assess the effects of cocaine on Fas-associated protein with death domain (FADD) system and its role in the activation of apoptotic vs nonapoptotic events and (2) ascertain whether animals selectively bred for their differential propensity to drug-seeking show differences in FADD levels or response to cocaine. Acute cocaine, through D(2) dopamine receptors, induced a dose-response increase in FADD protein in the cortex, with opposite effects over pFADD (Ser191/194), and no induction of apoptotic cell death (poly-(ADP-ribose) polymerase cleavage). FADD was increased by cocaine in cytosol (approximately 142%), membranes (approximately 23%) and nucleus (approximately 54%). The modulation of the FADD system showed tolerance of the acute effect over time, as well as a compensatory response on withdrawal that mirrored the acute effect--ie a transient FADD decrease on day 3 of withdrawal, both at mRNA and protein levels. In a second experiment, possible FADD differences were investigated in rats selectively bred for differential responsiveness to novelty, propensity for drug-seeking and cocaine sensitization. High-responders (HR), who were more prone to drug abuse, exhibited higher FADD and lower pFADD levels than low-responder (LR) rats. However, HR and LR rats showed similar rates of cocaine-induced apoptosis, and exhibited a parallel impact of cocaine over FADD within each phenotype. Thus, FADD is a signaling protein modulated by cocaine, regulating apoptosis/proliferative mechanisms in relation to its FADD/pFADD content. Interestingly, animals selectively bred for differential propensity to substance abuse show basal differences in the expression of this protein, suggesting FADD may also be a molecular correlate for the HR/LR phenotype.

Resolution analysis of finite fault source inversion using one- and three-dimensional Green's functions 2. Combining seismic and geodetic data

USGS Publications Warehouse

Wald, D.J.; Graves, R.W.

2001-01-01

Using numerical tests for a prescribed heterogeneous earthquake slip distribution, we examine the importance of accurate Green's functions (GF) for finite fault source inversions which rely on coseismic GPS displacements and leveling line uplift alone and in combination with near-source strong ground motions. The static displacements, while sensitive to the three-dimensional (3-D) structure, are less so than seismic waveforms and thus are an important contribution, particularly when used in conjunction with waveform inversions. For numerical tests of an earthquake source and data distribution modeled after the 1994 Northridge earthquake, a joint geodetic and seismic inversion allows for reasonable recovery of the heterogeneous slip distribution on the fault. In contrast, inaccurate 3-D GFs or multiple 1-D GFs allow only partial recovery of the slip distribution given strong motion data alone. Likewise, using just the GPS and leveling line data requires significant smoothing for inversion stability, and hence, only a blurred vision of the prescribed slip is recovered. Although the half-space approximation for computing the surface static deformation field is no longer justifiable based on the high level of accuracy for current GPS data acquisition and the computed differences between 3-D and half-space surface displacements, a layered 1-D approximation to 3-D Earth structure provides adequate representation of the surface displacement field. However, even with the half-space approximation, geodetic data can provide additional slip resolution in the joint seismic and geodetic inversion provided a priori fault location and geometry are correct. Nevertheless, the sensitivity of the static displacements to the Earth structure begs caution for interpretation of surface displacements, particularly those recorded at monuments located in or near basin environments. Copyright 2001 by the American Geophysical Union.

Effective use of surface-water management to control saltwater intrusion

NASA Astrophysics Data System (ADS)

Hughes, J. D.; White, J.

2012-12-01

The Biscayne aquifer in southeast Florida is susceptible to saltwater intrusion and inundation from rising sea-level as a result of high groundwater withdrawal rates and low topographic relief. Groundwater levels in the Biscayne aquifer are managed by an extensive canal system that is designed to control flooding, supply recharge to municipal well fields, and control saltwater intrusion. We present results from an integrated surface-water/groundwater model of a portion of the Biscayne aquifer to evaluate the ability of the existing managed surface-water control network to control saltwater intrusion. Surface-water stage and flow are simulated using a hydrodynamic model that solves the diffusive-wave approximation of the depth-integrated shallow surface-water equations. Variable-density groundwater flow and fluid density are solved using the Oberbeck--Boussinesq approximation of the three-dimensional variable-density groundwater flow equation and a sharp interface approximation, respectively. The surface-water and variable-density groundwater domains are implicitly coupled during each Picard iteration. The Biscayne aquifer is discretized into a multi-layer model having a 500-m square horizontal grid spacing. All primary and secondary surface-water features in the active model domain are discretized into segments using the 500-m square horizontal grid. A 15-year period of time is simulated and the model includes 66 operable surface-water control structures, 127 municipal production wells, and spatially-distributed daily internal and external hydrologic stresses. Numerical results indicate that the existing surface-water system can be effectively used in many locations to control saltwater intrusion in the Biscayne aquifer resulting from increases in groundwater withdrawals or sea-level rise expected to occur over the next 25 years. In other locations, numerical results indicate surface-water control structures and/or operations may need to be modified to control saltwater intrusion.

Stable genetic transformation of tomato plastids and expression of a foreign protein in fruit.

PubMed

Ruf, S; Hermann, M; Berger, I J; Carrer, H; Bock, R

2001-09-01

Transgenic chloroplasts offer unique advantages in plant biotechnology, including high-level foreign protein expression, absence of epigenetic effects, and gene containment due to the lack of transgene transmission through pollen. However, broad application of plastid genome engineering in biotechnology has been largely hampered by both the lack of chloroplast transformation systems for major crop plants and the usually low plastid gene expression levels in nongreen tissues such as fruits, tubers, and other storage organs. Here we describe the development of a plastid transformation system for tomato, Lycopersicon esculentum. This is the first report on the generation of fertile transplastomic plants in a food crop with an edible fruit. We show that chromoplasts in the tomato fruit express the transgene to approximately 50% of the expression levels in leaf chloroplasts. Given the generally very high foreign protein accumulation rates that can be achieved in transgenic chloroplasts (>40% of the total soluble protein), this system paves the way to efficient production of edible vaccines, pharmaceuticals, and antibodies in tomato.

The effectiveness of radon preventive and remedial measures in Irish homes.

PubMed

Long, S; Fenton, D; Cremin, M; Morgan, A

2013-03-01

It is estimated that approximately 100 000 Irish homes have radon concentrations above the reference level of 200 Bq m(-3). To minimise the number of new homes with this problem, building regulations require that all new homes built since July 1998 in high radon areas are installed with radon barriers during construction. Measurements on local authority homes in a number of high radon areas have allowed the impact of these new regulations to be assessed. In County Cork a reduction of up to 70% in the mean radon concentration was observed in homes built since 1998 relative to those built before this date. A reduction in both the number of homes exceeding the reference level and the maximum concentration measured in homes was also measured. Homes exceeding the reference level were remediated with the use of an active sump. The results of this remedial work are also presented and show that the mean reduction in radon concentration achieved was 92%.

Cruise noise of the 2/9th scale model of the Large-scale Advanced Propfan (LAP) propeller, SR-7A

NASA Technical Reports Server (NTRS)

Dittmar, James H.; Stang, David B.

1987-01-01

Noise data on the Large-scale Advanced Propfan (LAP) propeller model SR-7A were taken in the NASA Lewis Research Center 8 x 6 foot Wind Tunnel. The maximum blade passing tone noise first rises with increasing helical tip Mach number to a peak level, then remains the same or decreases from its peak level when going to higher helical tip Mach numbers. This trend was observed for operation at both constant advance ratio and approximately equal thrust. This noise reduction or, leveling out at high helical tip Mach numbers, points to the use of higher propeller tip speeds as a possible method to limit airplane cabin noise while maintaining high flight speed and efficiency. Projections of the tunnel model data are made to the full scale LAP propeller mounted on the test bed aircraft and compared with predictions. The prediction method is found to be somewhat conservative in that it slightly overpredicts the projected model data at the peak.

Cruise noise of the 2/9 scale model of the Large-scale Advanced Propfan (LAP) propeller, SR-7A

NASA Technical Reports Server (NTRS)

Dittmar, James H.; Stang, David B.

1987-01-01

Noise data on the Large-scale Advanced Propfan (LAP) propeller model SR-7A were taken in the NASA Lewis Research Center 8 x 6 foot Wind Tunnel. The maximum blade passing tone noise first rises with increasing helical tip Mach number to a peak level, then remains the same or decreases from its peak level when going to higher helical tip Mach numbers. This trend was observed for operation at both constant advance ratio and approximately equal thrust. This noise reduction or, leveling out at high helical tip Mach numbers, points to the use of higher propeller tip speeds as a possible method to limit airplane cabin noise while maintaining high flight speed and efficiency. Projections of the tunnel model data are made to the full scale LAP propeller mounted on the test bed aircraft and compared with predictions. The prediction method is found to be somewhat conservative in that it slightly overpredicts the projected model data at the peak.

Preliminary test results from a free-piston Stirling engine technology demonstration program to support advanced radioisotope space power applications

NASA Astrophysics Data System (ADS)

White, Maurice A.; Qiu, Songgang; Augenblick, Jack E.

2000-01-01

Free-piston Stirling engines offer a relatively mature, proven, long-life technology that is well-suited for advanced, high-efficiency radioisotope space power systems. Contracts from DOE and NASA are being conducted by Stirling Technology Company (STC) for the purpose of demonstrating the Stirling technology in a configuration and power level that is representative of an eventual space power system. The long-term objective is to develop a power system with an efficiency exceeding 20% that can function with a high degree of reliability for up to 15 years on deep space missions. The current technology demonstration convertors (TDC's) are completing shakedown testing and have recently demonstrated performance levels that are virtually identical to projections made during the preliminary design phase. This paper describes preliminary test results for power output, efficiency, and vibration levels. These early results demonstrate the ability of the free-piston Stirling technology to exceed objectives by approximately quadrupling the efficiency of conventional radioisotope thermoelectric generators (RTG's). .

Farfield inflight measurement of high-speed turboprop noise

NASA Technical Reports Server (NTRS)

Balombin, J. R.; Loeffler, I. J.

1982-01-01

A flight program was carried out to determine the variation of noise level with distance from a model high speed propeller. Noise measurements were obtained at different distances from a SR-3 propeller mounted on a JetStar aircraft, with the test instrumentation mounted on a Lear jet flown in formation. The propeller was operated at 0.8 flight Mach number, 1.12 helical tip Mach number and at 0.7 flight Mach number, 1.0 helical tip Mach number. The instantaneous pressure from individual blades was observed to rise faster at the 0.8 M flight speed, than at the 0.7 M flight speed. The measured levels appeared to decrease in good agreement with a 6 dB/doubling of distance decay, over the measurement range of approximately 16 m to 100 m distance. Further extrapolation, to the distances represented by a community, would suggest that the propagated levels during cruise would not cause a serious community annoyance.

Approximating Exponential and Logarithmic Functions Using Polynomial Interpolation

ERIC Educational Resources Information Center

Gordon, Sheldon P.; Yang, Yajun

2017-01-01

This article takes a closer look at the problem of approximating the exponential and logarithmic functions using polynomials. Either as an alternative to or a precursor to Taylor polynomial approximations at the precalculus level, interpolating polynomials are considered. A measure of error is given and the behaviour of the error function is…

Emission of 2-methyl-3-buten-2-ol by pines: A potentially large natural source of reactive carbon to the atmosphere

NASA Astrophysics Data System (ADS)

Harley, Peter; Fridd-Stroud, Verity; Greenberg, James; Guenther, Alex; Vasconcellos, PéRola

1998-10-01

High rates of emission of 2-methyl-3-buten-2-ol (MBO) were measured from needles of several pine species. Emissions of MBO in the light were 1 to 2 orders of magnitude higher than emissions of monoterpenes and, in contrast to monoterpene emissions from pines, were absent in the dark. MBO emissions were strongly dependent on incident light, behaving similarly to net photosynthesis. Emission rates of MBO increased exponentially with temperature up to approximately 35°C. Above approximately 42°C, emission rates declined rapidly. Emissions could be modeled using existing algorithms for isoprene emission. We propose that emissions of MBO from lodgepole and ponderosa pine are the primary source of high concentrations of this compound, averaging 1-3 ppbv, found in ambient air samples collected in Colorado at an isolated mountain site approximately 3050 m above sea level. Subsequent field studies in a ponderosa pine plantation in California confirmed high MBO emissions, which averaged 25 μg C g-1 h-1 for 1-year-old needles, corrected to 30°C and photon flux of 1000 μmol m-2 s-1. A total of 34 pine species growing at Eddy Arboretum in Placerville, California, were investigated, of which 11 exhibited high emissions of MBO (>5 μg C g-1 h-1), and 6 emitted small but detectable amounts. All the emitting species are of North American origin, and most are restricted to western North America. These results indicate that MBO emissions from pines may constitute a significant source of reactive carbon and a significant source of acetone, to the atmosphere, particularly in the western United States.

Safety approaches for high power modular laser operation

NASA Astrophysics Data System (ADS)

Handren, R. T.

1993-03-01

Approximately 20 years ago, a program was initiated at the Lawrence Livermore National Laboratory (LLNL) to study the feasibility of using lasers to separate isotopes of uranium and other materials. Of particular interest was the development of a uranium enrichment method for the production of commercial nuclear power reactor fuel to replace current more expensive methods. The Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) Program progressed to the point where a plant-scale facility to demonstrate commercial feasibility was built and is being tested. The U-AVLIS Program uses copper vapor lasers which pump frequency selective dye lasers to photoionize uranium vapor produced by an electron beam. The selectively ionized isotopes are electrostatically collected. The copper lasers are arranged in oscillator/amplifier chains. The current configuration consists of 12 chains, each with a nominal output of 800 W for a system output in excess of 9 kW. The system requirements are for continuous operation (24 h a day, 7 days a week) and high availability. To meet these requirements, the lasers are designed in a modular form allowing for rapid change-out of the lasers requiring maintenance. Since beginning operation in early 1985, the copper lasers have accumulated over 2 million unit hours at a greater than 90% availability. The dye laser system provides approximately 2.5 kW average power in the visible wavelength range. This large-scale laser system has many safety considerations, including high-power laser beams, high voltage, and large quantities (approximately 3000 gal) of ethanol dye solutions. The Laboratory's safety policy requires that safety controls be designed into any process, equipment, or apparatus in the form of engineering controls. Administrative controls further reduce the risk to an acceptable level. Selected examples of engineering and administrative controls currently being used in the U-AVLIS Program are described.

Quantum close coupling calculation of transport and relaxation properties for Hg-H2 system

NASA Astrophysics Data System (ADS)

Nemati-Kande, Ebrahim; Maghari, Ali

2016-11-01

Quantum mechanical close coupling calculation of the state-to-state transport and relaxation cross sections have been done for Hg-H2 molecular system using a high-level ab initio potential energy surface. Rotationally averaged cross sections were also calculated to obtain the energy dependent Senftleben-Beenakker cross sections at the energy range of 0.005-25,000 cm-1. Boltzmann averaging of the energy dependent Senftleben-Beenakker cross sections showed the temperature dependency over a wide temperature range of 50-2500 K. Interaction viscosity and diffusion coefficients were also calculated using close coupling cross sections and full classical Mason-Monchick approximation. The results were compared with each other and with the available experimental data. It was found that Mason-Monchick approximation for viscosity is more reliable than diffusion coefficient. Furthermore, from the comparison of the experimental diffusion coefficients with the result of the close coupling and Mason-Monchick approximation, it was found that the Hg-H2 potential energy surface used in this work can reliably predict diffusion coefficient data.

Effect on fast neutron irradiation to 4 dpa at 400{degrees}C on the properties of V-(4-5)Cr-(4-5)Ti alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zinkle, S.J.; Alexander, D.J.; Robertson, J.P.

1997-04-01

Tensile, Charpy impact and electrical resistivity measurements have been performed at ORNL on V-4Cr-4Ti and V-5Cr-5Ti specimens that were prepared at ANL and irradiated in the lithium-bonded X530 experiment in the EBR-II fast reactor. All of the specimens were irradiated to a damage level of about 4 dpa at a temperature of {approximately}400{degrees}C. A significant amount of radiation hardening was evident in both the tensile and Charpy impact tests. The irradiated V-4Cr-4Ti yield strength measured at {approximately}390{degrees}C was >800 MPa, which is more than three times as high as the unirradiated value. The uniform elongations of the irradiated tensile specimensmore » were typically {approximately}1%, with corresponding total elongations of 4-6%. The ductile to brittle transition temperature of the irradiated specimens was less than the unirradiated resistivity, which suggests that hardening associated with interstitial solute pickup was minimal.« less

A periodicity of approximately 1 hour in X-ray emission from the active galaxy RE J1034+396.

PubMed

Gierliński, Marek; Middleton, Matthew; Ward, Martin; Done, Chris

2008-09-18

Active galactic nuclei and quasars are thought to be scaled-up versions of Galactic black hole binaries, powered by accretion onto supermassive black holes with masses of 10(6)-10(9) M[symbol: see text], as opposed to the approximately 10 M [symbol: see text] in binaries (here M [symbol: see text] is the solar mass). One example of the similarities between these two types of systems is the characteristic rapid X-ray variability seen from the accretion flow. The power spectrum of this variability in black hole binaries consists of a broad noise with multiple quasi-periodic oscillations superimposed on it. Although the broad noise component has been observed in many active galactic nuclei, there have hitherto been no significant detections of quasi-periodic oscillations. Here we report the discovery of an approximately 1-hour X-ray periodicity in a bright active galaxy, RE J1034+396. The signal is highly statistically significant (at the 5.6 sigma level) and very coherent, with quality factor Q > 16. The X-ray modulation arises from the direct vicinity of the black hole.

Reverse-transformation austenite structure control with micro/nanometer size

NASA Astrophysics Data System (ADS)

Wu, Hui-bin; Niu, Gang; Wu, Feng-juan; Tang, Di

2017-05-01

To control the reverse-transformation austenite structure through manipulation of the micro/nanometer grain structure, the influences of cold deformation and annealing parameters on the microstructure evolution and mechanical properties of 316L austenitic stainless steel were investigated. The samples were first cold-rolled, and then samples deformed to different extents were annealed at different temperatures. The microstructure evolutions were analyzed by optical microscopy, scanning electron microscopy (SEM), magnetic measurements, and X-ray diffraction (XRD); the mechanical properties are also determined by tensile tests. The results showed that the fraction of stain-induced martensite was approximately 72% in the 90% cold-rolled steel. The micro/nanometric microstructure was obtained after reversion annealing at 820-870°C for 60 s. Nearly 100% reversed austenite was obtained in samples annealed at 850°C, where grains with a diameter ≤ 500 nm accounted for 30% and those with a diameter > 0.5 μm accounted for 70%. The micro/nanometer-grain steel exhibited not only a high strength level (approximately 959 MPa) but also a desirable elongation of approximately 45%.