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Local manipulation of electric fields at the atomic scale may enable new methods for quantum transport and creates new opportunities for field control of ferromagnetism and spin-based quantum information processing in semiconductors. We used a scanning tunneling microscope to position charged arsenic (As) vacancies in the gallium arsenide 110 [GaAs(110)] surface with atomic precision, thereby tuning the local electrostatic field experienced by single manganese (Mn) acceptors. The effects of this field are quantified by measuring the shift of an acceptor state within the band gap of GaAs. Experiments with varying tip-induced band-bending conditions suggest a large binding energy for surface-layer Mn, which is reduced by direct Coulomb repulsion when the As vacancy is moved nearby. 10.1126/science.1197434

DOI: 10.2514/1.29611 The purpose of this paper is to study the impact of the flight-loads effects on the free-play-induced limit cycle oscillation using a direct simulation approach. This is achieved by computing the transient responses of an F-16 aeroelastic model with various free-play angles in its horizontal tails under various trim conditions, while subjected to external excitations due to gust or pilot input command. It is found that for the restrained structures, limit cycle oscillation always occurs, even with a very small free-play limit, as long as the horizontal tail is unloaded. However, once the horizontal tail is loaded at a trim condition, limit cycle oscillation disappears, even with a large free-play limit up to [+ or -] 0.2 degrees. In contrast, for the unrestrained structures, even with large free-play limits up to [+ or -] 0.1 degrees, limit cycle oscillation occurs only within a short period of time when the horizontal tail is unloaded. This is because for a free-free aircraft, when the horizontal tail is unloaded, the aircraft is untrimmed and then a transient maneuver will be developed and, consequently, the horizontal tail is rapidly loaded. In addition, it is unlikely that the F-16 can maintain an unloaded horizontal tail for a sufficiently long time until the limit cycle oscillation is fully developed. This suggests that the military specification for control surface free-play limit ([+ or -] 0.017 degrees) is probably too stringent for the F-16 and can be relaxed to reduce the manufacturing and maintenance costs.

Fluid flow and heat transfer characteristics on and around a central pedestal and a secondary pedestal, mounted on a flat surface with an impinging jet, are investigated. Surface Nusselt numbers, pressure coefficients (in the form of normalized wall static pressure relative to freestream static pressure), and flow visualization results are given for jet Reynolds numbers of 23,000 and 2300. The dimensionless nozzle-to-surface distance L/d is 2, and the nondimensional height of the central pedestal H/D is 0.5. Results are given for different secondary pedestal heights and locations. Spatially averaged Nusselt numbers measured with secondary pedestals employed are 13% to 33% higher than values measured with no secondary pedestal. Local Nusselt numbers and wall pressure coefficients, measured with the secondary pedestal present, are different from values measured with no secondary pedestal, because of flow reattachment and the two counter-rotating recirculation zones located between the two pedestals, and small local regions of flow separation and recirculation located on top of the secondary pedestal. As such, the present multiple pedestal data with impinging jets are useful for a variety of electronics cooling arrangements. [DOI: 10.111511.2753884]

In euryhaline crabs, ion-transporting cells are clustered into osmoregulatory patches on the lamellae of the posterior gills. To examine changes in the branchial osmoregulatory patch in the blue crab Callinectes sapidus in response to change in salinity and to correlate these changes with other osmoregulatory responses, crabs were acclimated to a range of salinities between 10 and 35 ppt. When crabs that had been acclimated to 35 ppt were subsequently transferred to 10 ppt, both the size of the osmoregulatory patch on individual gill lamellae and the specific activity of [Na.sup.+],[K.sup.+]-ATPase in whole-gill homogenates increased only after the first 24 h of exposure to dilute seawater. Enzyme activity and size of patch area increased gradually and reached their maxima (increasing by 200% and 60%, respectively) 6 days following transfer to 10 ppt seawater and then remained at these levels. Patch size at acclimation varied inversely with the salinity for seawater dilutions below 26 ppt (the isosmotic point of the crab), although it did not vary in salinities at or above 26 ppt. Thus, the size of the patch clearly is modulated with acclimation salinity, but it increases only in those salinities in which the crab hyperosmoregulates. An increase in the total RNA/DNA ratio in gill homogenates, the lack of mitotic figures in the lamellae, and the lack of incorporation of bromodeoxyuridine into nuclei of lamellar epithelial cells during acclimation to dilute seawater were interpreted as evidence that no cell proliferation had occurred and that increases in the size of the osmoregulatory patch occurred through differentiation of existing gas exchange cells or of undifferentiated epithelial cells into ion-transporting cells., Introduction Estuarine crabs, such as the blue crab Callinectes sapidus Rathbun, 1896, hyperosmoregulate in dilute seawater. This regulation is facilitated by the enzyme [Na.sup.+],[K.sup.+]-ATPase located in epithelial cells of the [...]

Surface Nusselt numbers, pressure coefficients, and flow visualizations are presented which are measured as a turbulent jet, with a fully developed velocity profile, impinges on the cylindrical pedestal and on the surrounding flat surface. Thermochromic liquid crystals and shroud-transient techniques are used to measure spatially resolved surface temperature distributions, which are used to deduce local Nusselt numbers. Dimensionless pedestal heights H/D are 0, 0.5, 1.0, and 1.5, the jet Reynolds number Re is 23,000, and the surface distance to nozzle diameter L/d ranges from 2 to 10. Local Nusselt numbers drastically increase with a radial distance away from the stagnation point on top of the pedestal for H/D values of 0.5, 1.0, and 1.5. These are partially due to the small flow recirculation zones present on top of the pedestal, and mixing associated with the separation of flow streamlines near the edge of the upper surface on the pedestal. Local Nusselt numbers are also augmented at flat surface locations corresponding to positions where shear layers reattach downstream of the pedestal. In general, augmentation magnitudes become more pronounced as H/D becomes smaller because of greater vortex influences. Corresponding local Nusselt numbers, beneath shear layer reattachment locations for H/D =0.5, are 35 to 80% higher than values measured at the same flat surface locations when no pedestals are employed. [DOI: 10.1115/1.1849235]

The importance of genotype x country interactions for weaning and birth weight and postweaning gain between Argentina (AR), Canada (CA), Uruguay (UY), and the United States (US) for populations of Hereford cattle was investigated. Three sample data sets of computationally manageable sizes were formed for each trait and pairwise combination of countries to investigate possible interactions. Parameters were estimated for each sample data set via an accelerated EM-REML algorithm and multiple-trait animal models that considered either weaning or birth weight as a different trait in each country. Direct and maternal (in parentheses) weaning weight genetic correlation estimates for AR-CA, AR-UY, AR-US, CA-UY, CA-US, and UY-US were 0.82 (0.80), 0.81 (0.72), 0.81 (0.79), 0.83 (0.78), 0.85 (0.82), and 0.86 (0.81), respectively. Direct and maternal (in parentheses) birth weight genetic correlation estimates were 0.92 (0.62), 0.97, (0.85), and 0.99 (0.97) for AR-CA, AR-US, and CA-US, respectively. Birth weight was not analyzed for UY due to small amounts of data. Postweaning gain in CA and US was 160-d gain, and in AR and UY 345-d gain was used. Across-country direct genetic correlations for postweaning gain were estimated for each pairwise country data set using a model that considered weaning weight as the same trait across each country, whereas postweaning gain was treated as a different trait in each country. Direct genetic correlation estimates for postweaning gain for AR-CA, AR-UY, AR-US, CA-UY, CA-US, and US-UY were 0.64, 0.80, 0.51, 0.84, 0.92, and 0.83, respectively. The overall results indicate that weaning and birth weights of Hereford calves can be analyzed as the same trait in all countries with a common set of heritabilities and genetic correlations, after adjustment for heterogenous phenotypic variances across countries. Postweaning gain in CA and US can be considered as the same trait and analyzed using a single set of parameters. Postweaning gain in AR and UY should be considered as a separate trait from postweaning gain in CA and US, and postweaning gain in AR and UY can be considered as the same trait and analyzed using a common heritability, after adjustment for phenotypic variance differences between the two countries. Key Words: Beef Cattle, Genotype-Environment Interaction, International Comparisons

Thermal annealing and its effects on ta-C films is examined.

The donor Te was introduced to GaInP during organometallic vapor phase epitaxial growth utilizing the precursor diethyltelluride. The addition of high Te concentrations caused the removal of the CuPt ordering found in undoped layers. A change in the surface structure was observed to accompany a decrease in ordering. The surfaces became much smoother. A qualitative model was employed to explain this behavior based on the effect of Te on the step structure and the bonding at step edges.

GaAs/Al/GaAs asymmetric coupled double quantum well are investigated to determine the photoluminescence (PL) and photoluminescence excitation (PLE) of these wells. The investigation revealed the existence of seven peaks in PLE, which is also revealed by the multi-band envelope function approximation. The heavy-hole coupled excitations in the lowest levels in thermal equilibrium are caused by the temperature-dependent PL above 100 kelvin. The difference between the two levels causes the observed activation energy.

This paper documents a low-cost, qualitative evaluation scheme using a fuzzy set analysis for mapping slope failure potential (SFP). Four categories of factors affecting stability of natural slopes, i.e., geology , topography. meteorology, and environment, are considered. Each category involves two to five factors, and a total of 13 factors is used in the proposed evaluation scheme. A set of evaluation criteria was established for each adopted factor. In the proposed evaluation scheme, slope failure potential is assessed and recorded in linguistic terms based on the established criteria. The linguistic data or information obtained from the assessments is represented and processed using fuzzy sets. In this study, the analysis or computation involving fuzzy sets was performed using the Monte Carlo simulation technique. An SFP index to measure the slope failure potential is defined. Based on the computed SFP values for a large number of subareas or cells selected for an area studied, an SFP map can be developed. An example application is presented to demonstrate the method. The SFP map developed in the case study seems to be able to correctly predict the slope failure potential of the area studied., A low-cost, qualitative, evaluative technique for mapping slope failure potential is presented. The technique involves fuzzy set theory and was found to be accuratein predicting slope failure. The technique incorporates factors divided into geology, topography, meterology and environment categories. A total of 13 factors were involved in the analysis. Analysis is validated through records ofslope failures of the Mt. So-San region which was mapped via this technique.

There have been many studies to recycle abandoned Nd-Fe-B magnets. Of these, some studied the conversion of sintered Nd-Fe-B magnet scrap to bonded magnet powder. This conversion, however, has never been used in production yet. The present study aims to develop a highly coercive magnet powder for bonded magnets from Nd-Fe-B sintered magnet scrap. In general, the magnetic property of the powders is dramatically lost through crushing of the sintered magnet because of microstructural damage. The magnetic property of the powders is partly recovered by a heat-treatment due to the healing of microstructural damages. The coercivity of the powders could be fully restored by heat-treatment with a surface modifier such as Dy[F.sub.3]. Surface-morphology change and microstructural uniformity may lower the nucleation sites of reversed domains, which may be responsible for recovery of demagnetization loop squareness and an increase in [sub.i][H.sub.c]. An anisotropic powder obtained from the Nd-Fe-B magnet scrap exhibits [B.sub.r] = 11.6 kG, [sub.i][H.sub.c] = 13.3 kOe, and [(BH).sub.max] = 31.1 MGOe. Index Terms--Coercivity, magnet scrap, rare earth magnet (Nd-Fe-B), recycling.

The peculiar behavior observed in the TDE (Total Dose Experiment) on board the KITSAT-1 is identified as the thermal effect due to the change in the eclipse rate of the satellite. Similar behavior is seen in the laboratory experiment as the temperature of the RADFET, the TDE sensor, is varied from 20 [degrees] C to 80 [degrees] C while it is being irradiated with [Co.sup.60] [Gamma]-ray source. Present study focuses on the modeling effort of separating the radiation and thermal effects from the complicated data in which these two effects are simultaneously present. We derive the device parameters from the non-thermal irradiation data, and then include thermal annealing and conversion of oxide charges to estimate the oxide trap and interface state charges in the case of thermal variation. The model fits the experimental data quite successfully, which will enable us to estimate the pure radiation effect on the TDE experienced in space.

Low dose of some persistent organic pollutants predicts type 2 diabetes: a nested case-control study Lee DH, Steffes MW, Sjodin A, et at. Environ Health Perspect 2010;118:1235-1242. BACKGROUND: Low doses [...]

Heme iron, zinc and upper digestive tract cancer: the Iowa Women's Health Study. Lee DH, Anderson KE, Folsom AR, Jacobs DR Jr. Int J Cancer 2005 May 31;[Epub ahead of [...]