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The present research builds upon the extant literature as it assesses psychophysiological factors in relation to empathy, conflict resolution, and romantic relationship satisfaction. In this study, we examined physiological reactivity of individuals in the context of emotionally laden interactions with their romantic partners. Participants (N = 31) completed self-report measures and attended in-person data collection sessions with their romantic partners. Participants were guided through discussions of problems and strengths of their relationships in vivo with their partners while we measured participants' skin conductance level (SCL) and interbeat interval (IBI) of the heart. We hypothesized that participants' level of empathy towards their partners would be reflected by physiological arousal (as measured by SCL and IBI) and relationship satisfaction, such that higher levels of empathy would be linked to changes in physiological arousal and higher relationship satisfaction. Further, we hypothesized that differences would be found in physiological arousal (as measured by SCL and IBI) based on the type of conflict resolution strategy used by participants. Finally, we hypothesized that differences would be found in empathy towards partner and relationship satisfaction based on the type of conflict resolution strategies used by participants. Results partially supported hypotheses and were discussed in light of existing knowledge based on empirical and theoretical sources.

Scion-rootstock interactions were analyzed to test the interaction between environment and above-ground vine phenology. The experiment employed ‘Marechal Foch’ and ‘Vidal Blanc’ as reciprocally grafted, own-rooted, and self-grafted vines. Results suggest that genetically complex phenological factors were under the control of the scion cultivar. The effect of the scion on fruit composition was related to differences in yield between the cultivars. Other effects are secondary in nature as a result of vine vigor and shoot density. Factors potentially under specific root influence, (e.g., fruit-set, water status, nutrition, soil pH, salinity, or root pests) were not limiting in this experiment.

Meteorite heat capacity (specific heat) is an essential parameter in modeling many aspects of the orbital and internal evolution of small solar system bodies, and can be a tool for characterization of the material in a meteorite itself. We have devised a novel method for the measurement of this quantity in whole-rock samples of meteorites, at low temperatures typical of asteroids. We insert the sample in liquid nitrogen, measure the mass of nitrogen boiled off due to the heat within the sample, and calibrating against measurements of pure quartz with a temperature-averaged heat capacity of 494 J/kg K we calculate the temperature-average heat capacity of the sample. We show that this method is accurate, rapid, inexpensive, and non-destructive. Preliminary results for chondrites and metal rich meteorites are in excellent agreement with the literature data for meteorites, and hold the promise that such measurements may not only produce values useful to modelers but they also may provide an efficient way to classify whole meteorite samples and characterize subtle differences between meteorites of different compositional classes.

We present observations of the binary near-Earth Asteroid (175706) 1996 FG3 in the 2–4 μm spectral region, obtained on multiple nights using the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). We find evidence for an absorption band of ∼5–10% (depending on the night and details of continuum choice), diagnostic for hydrated/hydroxylated minerals on the asteroid surface. This demonstrates that the optical surface of 1996 FG3 has not been heated to dehydrating temperatures. Sample-return missions targeting 1996 FG3 will likely find relatively fresh areas for sampling.

Water and hydroxyl, once thought to be found only in the primitive airless bodies that formed beyond roughly 2.5-3 AU, have recently been detected on the Moon and Vesta, which both have surfaces dominated by evolved, non-primitive compositions. In both these cases, the water/OH is thought to be exogenic, either brought in via impacts with comets or hydrated asteroids or created via solar wind interactions with silicates in the regolith or both. Such exogenic processes should also be occurring on other airless body surfaces. To test this hypothesis, we used the NASA Infrared Telescope Facility (IRTF) to measure reflectance spectra (2.0 to 4.1 {\mu}m) of two large near-Earth asteroids (NEAs) with compositions generally interpreted as anhydrous: 433 Eros and 1036 Ganymed. OH is detected on both of these bodies in the form of absorption features near 3 {\mu}m. The spectra contain a component of thermal emission at longer wavelengths, from which we estimate thermal of 167+/- 98 J m-2s-1/2K-1 for Eros (consistent with previous estimates) and 214+/- 80 J m-2s-1/2K-1 for Ganymed, the first reported measurement of thermal inertia for this object. These observations demonstrate that processes responsible for water/OH creation on large airless bodies also act on much smaller bodies., Comment: 24 pages, 6 figures, 5 tables. Accepted to Icarus

In May of 2011, NASA selected the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission as the third mission in the New Frontiers program. The other two New Frontiers missions are New Horizons, which explored Pluto during a flyby in July 2015 and is on its way for a flyby of Kuiper Belt object 2014 MU69 on Jan. 1, 2019, and Juno, an orbiting mission that is studying the origin, evolution, and internal structure of Jupiter. The spacecraft departed for near-Earth asteroid (101955) Bennu aboard an United Launch Alliance Atlas V 411 evolved expendable launch vehicle at 7:05 p.m. EDT on September 8, 2016, on a seven-year journey to return samples from Bennu. The spacecraft is on an outbound-cruise trajectory that will result in a rendezvous with Bennu in August 2018. The science instruments on the spacecraft will survey Bennu to measure its physical, geological, and chemical properties, and the team will use these data to select a site on the surface to collect at least 60 g of asteroid regolith. The team will also analyze the remote-sensing data to perform a detailed study of the sample site for context, assess Bennus resource potential, refine estimates of its impact probability with Earth, and provide ground-truth data for the extensive astronomical data set collected on this asteroid. The spacecraft will leave Bennu in 2021 and return the sample to the Utah Test and Training Range (UTTR) on September 24, 2023., Comment: 89 pages, 39 figures, submitted to Space Science Reviews - OSIRIS-REx special issue

FET-based switched filters do not occupy a large space in the literature due to the high loss of the switches relative to other technologies. The Super-Lattice Castellated Field Effect Transistor (SLCFET) is a low loss, high isolation, broadband RF switch that meets this need. A 4 channel tunable band pass filter employing SLCFET switches in a splitter/combiner network was fabricated in order to demonstrate the enabling capability of the SLCFET for this application. Each filter state employed a novel, high-Q LC circuit. The insertion loss of the MMIC passbands was around -6.5 dB, of which -1.3 dB was attributable to the six Single Pole Double Throw (SPDT) switches in the network. Breakout SPDTs were measured from 0.5 to 25 GHz. Measured insertion loss at 18 GHz was -0.41 ± 0.1 dB and isolation was -28.8 ± 0.1 dB, for 35 SPDTs on the wafer.

The Super-Lattice Castellated Field Effect Transistor (SLCFET) uses a super-lattice in the channel region to form multiple parallel current paths in conjunction with castellations etched into that super-lattice to provide a sidewall gate structure. The sidewall gate permits the gate applied electric field to penetrate between the parallel 2DEG layers, allowing the carriers to be depleted out prior to avalanche breakdown within the material, as would occur with a conventional gate structure. Using an AlGaN/GaN super-lattice, we report on this method as a way to scale RF switch performance, decreasing ON resistance without significantly increasing OFF capacitance, with a median measured ON resistance of 0.38 Ω-mm and a median measured OFF capacitance of 0.21 pF/mm, leading to an RF switch figure of merit, FCO=2.0 THz. 90/10 and 10/90 fall and rise times for the SLCFET have been measured to be faster than 100 nsec, while the RF power handling for a series SLCFET has been measured at 10 GHz to be greater than 10 W without loss compression. Wideband SPDT RF switch performance over a 0.5–20 GHz bandwidth with |−30| dB of isolation has been achieved.

To meet the large current handling requirements of modern power conditioning systems, paralleling of a large number of devices is required. This increases cost and complexity through dicing, soldering, and forming multiple wire bonds. Furthermore, paralleling discrete devices increases package volume/weight and reduces power density. To overcome these complexities, PiN diodes were designed, fabricated at high yields, tested, and interconnected on a three-inch 4H-SiC wafer to form an 11.72 cm2 wafer-scale diode. The wafer-scale diode exhibited a breakdown voltage of 1790 V at an extremely low leakage current density of less than 0.002 mA/cm2. Under pulsed conditions, the peak current through the wafer-scale diode is 64.3 kA with a forward voltage drop of 10.3 V. The dissipated energy was 382 J and the action exceeded 1.7 MA2-sec.

The multi-zone junction termination extension (MJTE) is a widely used edge termination technique for achieving high voltage SiC devices. It is commonly implemented with multiple lithography and implantation events. In order to reduce process complexity, cycle time, and cost, a single photolithography and single implant MJTE technique has been successfully developed. The method utilizes a pattern of finely graduated oxide windows that filter the implant dose and create a graded MJTE in a single implant and single photolithography step. Based on this technique, 6 kV / 0.09 cm2 PiN diodes were fabricated utilizing a 120-zone single-implant JTE design. This novel single-implant MJTE design captures 93% of the ideal breakdown voltage and has comparable performance and yield to a baseline three implant process.

Modern power conditioning systems require large active area devices which can support high currents. Though the breakdown and thermal properties of SiC make it an excellent choice for power switching applications, active area size is currently limited due to material and processing defects. One alternative is to parallel discrete diced die to achieve large active areas. However, this increases cost and complexity through dicing, soldering, and forming multiple wire bonds. Furthermore, paralleling discrete devices increases package volume/weight and reduces power density. To overcome these issues and achieve devices of high current switching capabilities, thyristors were designed and fabricated for the purpose of wafer-scale interconnection - which avoids the need of dicing and bonding and can achieve significant current density improvement over the paralleled diced device approach. Discrete thyristors fabricated for interconnection exhibited excellent yields and good uniformity of both blocking and on-state characteristics, showing great promise for large-scale interconnection.

Electron-hole recombination-induced stacking faults have been shown to degrade the electrical characteristics of SiC power pin and MPS diodes and DMOSFETs with thick drift epitaxial layers. In this paper, we investigate the effects of bipolar injection induced stacking faults on the electrical characteristics of p+ ion-implanted high-voltage vertical-channel JFETs with 100-μm drift epilayers. The JFETs were stressed at a fixed gate-drain bipolar current density of 100 A/cm2 for five hours, which led to degradation of the forward gate-drain p-n junction and on-state conduction. The degradation was fully reversed by annealing at 350 °C for 96 hours. Forward and reverse gate-source, transfer, reverse gate-drain, and blocking voltage JFET characteristics exhibit no degradation with bipolar stress. Non-degraded characteristics remain unaffected by annealing events. Consequently, should minority carrier injection occur in JFETs operating at elevated temperatures no stacking fault induced degradations are expected. This eliminates the need for specialty substrates with suppressed densities of basal plane dislocations in the fabrication of high-voltage SiC JFETs for high temperature applications.

We report radar, photometric, and spectroscopic observations of near-Earth Asteroid (136617) 1994 CC. The radar measurements were obtained at Goldstone (8560 MHz, 3.5 cm) and Arecibo (2380 MHz, 12.6 cm) on 9 days following the asteroid’s approach within 0.0168 AU on June 10, 2009. 1994 CC was also observed with the Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes (PROMPT) on May 21 and June 1‐3. Visible-wavelength spectroscopy was obtained with the 5-m Hale telescope at Palomar on August 25. Delay-Doppler radar images reveal that 1994 CC is a triple system; along with

We present observations of Asteroid 21 Lutetia collected 2003–2008 using the SpeX instrument on the NASA Infrared Telescope Facility (IRTF) covering 2–4 μm. We also reevaluate NSFCam observations obtained in 1996 (Rivkin, A.S., Lebofsky, L.A., Clark, B.E., Howell, E.S., Britt, D.T. [2000]. Icarus 145, 351–368). Taken together, these show deeper 3-μm band depths (of order 3–5%) in the southern hemisphere of Lutetia, and shallower band depths (of order 2% or less) in the north. Such variation is consistent with observations at shorter wavelength by previous workers (Nedelcu, D.A. et al. [2007]. Astron. Astrophys. 470, 1157–1164; Lazzarin, M. et al. [2010]. Mon. Not. R. Astron. Soc. 408, 1433–1437), who observed hemispheric-level variations from C-like spectra to X-like spectra. While the shallowness of absorption bands on Lutetia hinders identification of its surface composition, goethite appears plausible as a constituent in its southern hemisphere (Beck, P., Quirico, E., Sevestre, D., Montes-Hernandez, G., Pommerol, A., Schmitt, B. [2011]. Astron. Astrophys. 526, A85–A89). Mathematical models of space weathered goethite are most consistent with Lutetia’s southern hemisphere spectrum, but more work and further observations are necessary to confirm this suggestion.

We report new radar observations of E-class Asteroid 64 Angelina and M-class Asteroid 69 Hesperia obtained with the Arecibo Observatory S-band radar (2480 MHz, 12.6 cm). Our measurements of Angelina’s radar bandwidth are consistent with reported diameters and poles. We find Angelina’s circular polarization ratio to be 0.8 ± 0.1, tied with 434 Hungaria for the highest value observed for main-belt asteroids and consistent with the high values observed for all E-class asteroids (Benner, L.A.M., Ostro, S.J., Magri, C., Nolan, M.C., Howell, E.S., Giorgini, J.D., Jurgens, R.F., Margot, J.L., Taylor, P.A., Busch, M.W., Shepard, M.K. [2008]. Icarus 198, 294–304; Shepard, M.K., Kressler, K.M., Clark, B.E., Ockert-Bell, M.E., Nolan, M.C., Howell, E.S., Magri, C., Giorgini, J.D., Benner, L.A.M., Ostro, S.J. [2008b]. Icarus 195, 220–225). Our radar observations of 69 Hesperia, combined with lightcurve-based shape models, lead to a diameter estimate, Deff = 110 ± 15 km, approximately 20% smaller than the reported IRAS value. We estimate Hesperia to have a radar albedo of σ ˆ OC = 0.45 ± 0.12 , consistent with a high-metal content. We therefore add 69 Hesperia to the Mm-class (high metal M) (Shepard, M.K., Clark, B.E., Ockert-Bell, M., Nolan, M.C., Howell, E.S., Magri, C., Giorgini, J.D., Benner, L.A.M., Ostro, S.J., Harris, A.W., Warner, B.D., Stephens, R.D., Mueller, M. [2010]. Icarus 208, 221–237), bringing the total number of Mm-class objects to eight; this is 40% of all M-class asteroids observed by radar to date.

We observed near-Earth Asteroid (8567) 1996 HW1 at the Arecibo Observatory on six dates in September 2008, obtaining radar images and spectra. By combining these data with an extensive set of new lightcurves taken during 2008–2009 and with previously published lightcurves from 2005, we were able to reconstruct the object’s shape and spin state. 1996 HW1 is an elongated, bifurcated object with maximum diameters of 3.8 × 1.6 × 1.5 km and a contact-binary shape. It is the most bifurcated near-Earth asteroid yet studied and one of the most elongated as well. The sidereal rotation period is 8.76243 ± 0.00004 h and the pole direction is within 5° of ecliptic longitude and latitude (281°, −31°). Radar astrometry has reduced the orbital element uncertainties by 27% relative to the a priori orbit solution that was based on a half-century of optical data. Simple dynamical arguments are used to demonstrate that this asteroid could have originated as a binary system that tidally decayed and merged.

We compare 13 near-infrared (0.8–2.4 μm) spectra of two low albedo C complex outer-belt asteroid families: Themis and Veritas. The disruption ages of these two families lie at opposite extremes: 2.5 ± 1.0 Gyr and 8.7 ± 1.7 Myr, respectively. We found striking differences between the two families, which show a range of spectral shapes and slopes. The seven Themis family members (older surfaces) have “red” (positive) slopes in the 1.6–2.4 μm region; in contrast, the six Veritas members (younger surfaces) have significantly “flatter” slopes at these same wavelengths. Moreover, the two families are characterized by different concavity at shorter (1.0–1.5 μm) wavelengths with the Themis group being consistently flat or concave up (smile) and the Veritas group being consistently concave down (frown). Each family contains a broad range of diameters, suggesting our results are not due to comparisons of asteroids of different sizes. The statistically significant clustering of the two spectral groups could be explained by one of the following three possibilities or a combination of them: (1) space weathering effects, (2) differences in original composition, or (3) differences in thermal history perhaps as a result of the difference in parent body sizes. As a result of our analyses, we propose a new method to quantify broad and shallow structures in the spectra of primitive asteroids. We found reasonable matches between the observed asteroids and individual carbonaceous chondrite meteorites. Because these meteoritic fits represent fresh surfaces, space weathering is neither necessary nor ruled out as an explanation of spectral differences between families. The six Veritas family near-infrared (NIR) spectra represent the first NIR analysis of this family, thus significantly increasing our understanding of this family over these wavelengths.

A time stepping procedure is proposed for a coupled fluid model motivated by the dynamic core of the atmosphere-ocean system. The method exploits properties of the atmosphere-ocean system to obtain efficiency. The momentum equations for the two fluids may be solved in parallel with different time step sizes. Stability is maintained with large time steps via a balanced two-way passing of momentum flux. Numerical tests are provided that demonstrate the efficiency of the method. Published 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2012

Here we show results from thermal-infrared observations of km-sized binary near-Earth asteroids (NEAs). We combine previously published thermal properties for NEAs with newly derived values for three binary NEAs. The η value derived from the near-Earth asteroid thermal model (NEATM) for each object is then used to estimate an average thermal inertia for the population of binary NEAs and compared against similar estimates for the population of non-binaries. We find that these objects have, in general, surface temperatures cooler than the average values for non-binary NEAs as suggested by elevated η values. We discuss how this may be evidence of higher-than-average surface thermal inertia. This latter physical parameter is a sensitive indicator of the presence or absence of regolith: bodies covered with fine regolith, such as the Earth’s moon, have low thermal inertia, whereas a surface with little or no regolith displays high thermal inertia. Our results are suggestive of a binary formation mechanism capable of altering surface properties, possibly removing regolith: an obvious candidate is the YORP effect. We present also newly determined sizes and geometric visible albedos derived from thermal-infrared observations of three binary NEAs: (5381) Sekhmet, (153591) 2001 SN 263 , and (164121) 2003 YT 1 . The diameters of these asteroids are 1.41 ± 0.21 km, 1.56 ± 0.31 km, and 2.63 ± 0.40 km, respectively. Their albedos are 0.23 ± 0.13, 0.24 ± 0.16, and 0.048 ± 0.015, respectively.

The authors demonstrate for the first time the injection of electrons across an n-type to p-type silicon junction and their subsequent tunneling from approximately 1 μm tall p-type silicon points into a vacuum gap. The diffusive flow of these minority carriers in the p-type material is controlled by the application of a bias voltage in the form of a base contact metallization contact on the p-type silicon, in analogy with a bipolar junction transistor. Using an array density of 4×106 tips/cm2, the authors measured a maximum average current of 1 nA per tip. Increasing the base contact bias voltage from 0 to ∼1 V changes the emission from a supply limited regime typically observed with p-type silicon emitters, bringing the emitted current back to a linear Fowler–Nordheim characteristic similar to that observed previously by photon generation of carriers in p-type silicon tips. The authors finally note that in our short tips, minority carrier flow should be a nondissipative largely adiabatic diffusive transp...

Using the S-band radar at Arecibo Observatory, we observed six new M-class main-belt asteroids (MBAs), and re-observed one, bringing the total number of Tholen M-class asteroids observed with radar to 19. The mean radar albedo for all our targets is σ ˆ OC = 0.28 ± 0.13 , significantly higher than the mean radar albedo of every other class (Magri, C., Nolan, M.C., Ostro, S.J., Giorgini, J.D. [2007]. Icarus 186, 126–151). Seven of these objects (Asteroids 16 Psyche, 129 Antigone, 216 Kleopatra, 347 Pariana, 758 Mancunia, 779 Nina, 785 Zwetana) have radar albedos indicative of a very high metal content ( mean σ ˆ OC = 0.41 ± 0.13 ) , and consistent with a remnant iron/nickel core interpretation (irons) or exotic high metal meteorite types such as CB. We propose designating these high radar albedo objects as Mm. Two asteroids, 110 Lydia and 678 Fredegundis, have more moderate radar albedos ( mean σ ˆ OC = 0.22 ) , but exhibit high values ( σ ˆ OC ∼ 0.35 ) at some rotation phases suggesting a significant metal content. The remaining 10 objects have moderate radar albedos ( σ ˆ OC = 0.20 ± 0.06 ) at all rotation phases. Most of our targets have visible/near-infrared spectra (Hardersen, P.S., Gaffey, M.J., Abell, P.A. [2005]. Icarus 175, 141–158; Fornasier, S., Clark, B.E., Dotto, E., Migliorini, A., Ockert-Bell, M., Barucci, M.A. [2009]. Icarus, submitted for publication) that indicate the presence of at least some silicate phases. All of the non-Mm asteroids show a positive correlation between visual and radar albedo but the reasons for this are not clear. All of the higher radar albedo targets (the 7 Mm asteroids, Lydia, and Fredegundis) show moderate to large variations in radar albedo with rotation phase. We suggest that their high radar reflectivity exaggerates irregularities in the asteroid shape to cause this behavior. One-third of our targets show evidence for asteroid-scale concavities or bifurcation. Based on all the evidence available, we suggest that most Tholen M-class asteroids are not remnant iron cores or enstatite chondrites, but rather collisional composites of silicates and irons with compositions more analogous to stony-iron meteorites and high-iron carbonaceous chondrites.

In this work a finite element method for a dual-mixed approximation of generalized Stokes problems in two or three space dimensions is studied. A variational formulation of the generalized Stokes problems is accomplished through the introduction of the pseudostress and the trace-free velocity gradient as unknowns, yielding a twofold saddle point problem. The method avoids the explicit computation of the pressure, which can be recovered through a simple post-processing technique. Compared with an existing approach for the same problem, the method presented here reduces the global number of degrees of freedom by up to one-third in two space dimensions. The method presented here also represents a connection between existing dual-mixed and pseudostress methods for Stokes problems. Existence, uniqueness, and error results for the generalized Stokes problems are given, and numerical experiments that illustrate the theoretical results are presented. Copyright © 2010 John Wiley & Sons, Ltd.

The partial solubility of mineral aerosols collected on the windward side of Oahu, Hawaii, was determined by suspending aerosol laden filters in samples of filtered surface seawater and determining the amount of dissolved Al released over a period of four days. The results showed that 80% of the dissolvable Al was released rapidly, within the first 24 h, and that a further 20% was released slowly over the next three days. The mass-based fractional solubility varied from 0.087–14.3% with a mean value of 4.6%. The total dissolvable Al (1st plus 2nd mode) was well correlated with the total charge of nitrate and non seasalt sulphate (nss) ( R 2 = 0.78, R 2 = 0.84) on replicate filters. These results imply that the abundance of atmospheric acids (derived from nitrate and sulphur species) in the atmosphere appears to be one of the major factors controlling the fractional solubility of atmospheric dust in this region. In addition, the results indicate that as this field of study develops there is an urgent need to develop a consensus on the matrix used for defining the solubility of dusts and the development of protocols that eliminate artefacts associated with the determining solubilities that will permit comparison of data between different research groups working in different regions.

Arecibo radar imagery of Comet 8P/Tuttle reveals a 10-km-long nucleus with a highly bifurcated shape consistent with a contact binary. A separate echo component was also detected from large (>cm-size), slow-moving grains of the type expected to contribute to the Ursid meteor stream.

A recessed implanted-gate short-channel 1290-V normally-OFF 4H-SiC vertical-channel JFET (VJFET), fabricated in seven photolithographic-levels, with a single masked ion-implantation and no epitaxial regrowth, is evaluated for efficient power conditioning. Under unipolar high-current-gain operation, which is required for efficient power switching, the 1200-V N-OFF (enhancement mode) VJFET exhibits prohibitively high on-state resistance. Comparison with 1200-V normally-ON VJFETs, fabricated on the same wafer, confirms experimentally that the strong gate-depletion-region overlap required for 1200-V normally-OFF blocking is the principal contributor to the prohibitively high specific on-state resistance observed under high current-gain VJFET operation. Recessed-implanted-gate VJFET channel-region optimization simulations (assuming a single commercial implantation and no epitaxial-regrowth) revealed that although aggressively increasing channel doping lowers resistance, the corresponding reduction in source mesa-width can prohibitively limit manufacturability.

Bi-directional solid-state-circuit-breakers (SSCBs) are highly desirable in power-electronic fault-protection applications due to their high actuation speed and repeated fault isolation capability. Normally-on SiC vertical-channel JFETs (VJFETs) are excellent candidates for high power/temperature scalable SSCB applications as majority carrier devices with low conduction losses and stable +300°C thermal characteristics. 600-V / 2-A bi-directional power flow was demonstrated using two VJFETs connected back-to-back with their sources in common. The low VJFET pre-breakdown leakage currents and sharp onset of breakdown are critical in enabling bi-directional power flow. 0.1-cm2 low conduction-loss VJFETs were designed for efficient and reliable SSCB applications.

The underrepresentation of blacks in the healthcare professions may have direct implications for the health outcomes of minority patients, underscoring the importance of understanding movement through the educational pipeline into professional healthcare careers by race. We jointly model individuals' postsecondary decisions including enrollment, college type, degree completion, and choosing a healthcare occupation requiring an advanced degree. We estimate the parameters of the model with maximum likelihood using data from the NLS-72. Our results emphasize the importance of pre-collegiate factors and of jointly examining the full chain of educational decisions in understanding the sources of racial disparities in professional healthcare occupations.

Diaphyseal bone from normal Sprague-Dawley rats was delipidated in chloroform-methanol and demineralized in 0.6 N HCl at 4 degrees C. The bones were then implanted for 7-28 days into rats made rachitic by a low-phosphate, vitamin D-deficient diet (VDP-) for 3 weeks. Bones from VDP- and normal rats were also implanted into normal hosts. When normal rats were used as the host environment, a consistent sequence of cartilage induction and bone formation was observed. Demineralized rachitic bone (RB) implanted into normal host rats resulted in cartilage and bone induction similar to that seen for normal bone (NB) implants. Transmission electron microscopy of RB in normal hosts revealed morphologically normal chondrocytes and cartilage matrix with normal mineralization. In contrast, implantation of NB in VDP- hosts resulted in delayed chondrogenesis and lack of calcification. Furthermore, similar results were observed when RB was implanted into VDP- hosts. Treatment of VDP- hosts with either 1 alpha-hydroxyvitamin D3 or 24,25-dihydroxyvitamin D3 did not accelerate the sequential appearance of precartilage or cartilage. However, 24,25-(OH)2D3 administered alone or in combination with 1 alpha-OHD3 significantly increased the amount of calcified cartilage observed at 2 weeks postimplantation compared to implants from either untreated VDP-hosts or those treated only with 1 alpha-OHD3. New bone formation was observed at 4 weeks postimplantation in all vitamin D-treated groups as determined by von Kossa staining or direct electron microscope examination. There was no apparent difference in the quantitative or qualitative bone formed within the various vitamin D-treated groups. Serum calcium and phosphorus levels were lower and alkaline phosphatase levels were higher in VDP- hosts compared with normal animals or those treated with vitamin D metabolites. The results of this study show a reduction in the capacity of progenitor cells in VDP- rat hosts to respond to osteoinductive factor(s). This impaired response appears to be corrected by vitamin D metabolites.

SUMMARY For budding yeast to ensure formation of only one bud, cells must polarize toward one, and only one, site. Polarity establishment involves the Rho family GTPase Cdc42, which concentrates at polarization sites via a positive feedback loop. To assess whether singularity is linked to the specific Cdc42 feedback loop, we disabled the yeast cell’s endogenous amplification mechanism and synthetically rewired the cells to employ a different positive feedback loop. Rewired cells violated singularity, occasionally making two buds. Even cells that made only one bud sometimes initiated two clusters of Cdc42, but then one cluster became dominant. Mathematical modeling indicated that, given sufficient time, competition between clusters would promote singularity. In rewired cells, competition occurred slowly and sometimes failed to develop a single ‘‘winning’’ cluster before budding. Slowing competition in normal cells also allowed occasional formation of two buds, suggesting that singularity is enforced by rapid competition between Cdc42 clusters.

The numerical simulation of viscoelastic fluid flow becomes more difficult as a physical parameter, the Weissenberg number, increases. Specifically, at a Weissenberg number larger than a critical value, the iterative nonlinear solver fails to converge, a phenomenon known as the high Weissenberg number problem. In this work we describe the application and implementation of continuation methods to the nonlinear Johnson–Segalman model for steady-state viscoelastic flows. Simple, natural, and pseudo-arclength continuation approaches in Weissenberg number are investigated for a discontinuous Galerkin finite element discretization of the equations. Computations are performed for a benchmark contraction flow and, several aspects of the performance of the continuation methods including high Weissenberg number limits, are discussed.

The binding of the [ Au ( PMe 3 ) ] + fragment to cysteine, selenocysteine and the tetrapeptides H2NGlyCysAGlyCOOH (A = Cys, Sec) has been investigated by DFT methods as a model for the binding of gold(I) to the selenium-containing active site of thioredoxin reductase. The calculations demonstrate both a higher acidity of Se–H compared to S–H and a stronger binding of gold at the selenium site compared to sulphur. Se–H dissociation at the selenium site increases the reducing power of the tetrapeptide H2NGlyCysSecGlyCOOH whilst gold coordination at selenium has the opposite effect.

Accurate and realistic characterizations of flood hazards on desert piedmonts and playas are increasingly important given the rapid urbanization of arid regions. Flood behavior in arid fluvial systems differs greatly from that of the perennial rivers upon which most conventional flood hazard assessment methods are based. Additionally, hazard assessments may vary widely between studies or even contradict other maps. This study's chief objective was to compare and evaluate landscape interpretation and hazard assessment between types of maps depicting assessments of flood risk in Ivanpah Valley, NV, as a case study. As a secondary goal, we explain likely causes of discrepancy between data sets to ameliorate confusion for map users. Four maps, including three different flood hazard assessments of Ivanpah Valley, NV, were compared: (i) a regulatory map prepared by FEMA, (ii) a soil survey map prepared by NRCS, (iii) a surficial geologic map, and (iv) a flood hazard map derived from the surficial geologic map, both of which were prepared by NBMG. GIS comparisons revealed that only 3.4% (33.9 km 2 ) of Ivanpah Valley was found to lie within a FEMA floodplain, while the geologic flood hazard map indicated that ~ 44% of Ivanpah Valley runs some risk of flooding (Fig. 2D). Due to differences in mapping methodology and scale, NRCS data could not be quantitatively compared, and other comparisons were complicated by differences in flood hazard class criteria and terminology between maps. Owing to its scale and scope of attribute data, the surficial geologic map provides the most useful information on flood hazards for land-use planning. This research has implications for future soil geomorphic mapping and flood risk mitigation on desert piedmonts and playas. The Ivanpah Valley study area also includes the location of a planned new international airport, thus this study has immediate implications for urban development and land-use planning near Las Vegas, NV.

For the first time, large area 10 kV SiC power devices are being produced capable of yielding power modules for high-frequency megawatt power conversion. To this end, the switching performance and power dissipation of silicon carbide (SiC) n-channel IGBTs and MOSFETs are evaluated using numerical simulations software over an extended current range to determine the best device suitable for 10 kV applications. Each device is also optimized for minimal forward voltage drop in the on-state.

Objective: To investigate microbiology laboratory reporting policies, whether practitioners working in primary care adhered to the relevant guidelines when submitting swabs from venous leg ulcers (VLUs), and the impact of laboratory reports on antibiotic usage for VLUs. Method: Questionnaires were sent to all microbiology laboratories in England and Wales, and to clinicians who had submitted VLU swabs to one laboratory. Results: Ninety-five (47%) laboratories responded. Laboratories processed a mean of 7.3 leg ulcer swabs/100,000 population/week but were often unable to identify the leg ulcer aetiology from the clinical details provided. All laboratories stated that they routinely reported group A haemolytic streptococci and meticillin-sensitive and resistant Staphylococcus aureus; 75% always reported antibiotic susceptibility for these isolates. The majority reported other beta-haemolytic streptococci. A total of 126 clinicians (64%) returned their questionnaires; 100 had confirmed in their swab submission that the ulcer was of venous aetiology and so were included in the analysis. Eighty per cent of the swabs were submitted in accordance with guidelines, with increased pain (61%) being the most common reason. Discharge/exudate (52%) and malodour (41%) were common reasons for swab submissions, even though the guidelines do not cite them as clinical signs of infection. Reporting of antibiotic susceptibilities was associated with increased antibiotic usage. Conclusion: Clinicians in primary care generally adhere to guidelines when submitting VLU specimens for microbiological investigation. Clinicians need to include clinical information with the swab so that laboratories can interpret the microbiology results. To reduce the use of antibiotics in the management of VLUs, laboratories need to be selective in their organism and antibiotic-susceptibility reporting. Declaration of interest: None.

Three large-area 10-kV 4H-SiC DMOSFET designs are compared with respect to their design, die area, breakdown yield, and ON-state yield. The largest of these DMOSFETs had 0.62 cm2 of active area on a 1-cm2 die, with a 10-kV device producing 40 A at a gate field of 3 MV/cm. Two designs used linear interdigitated fingers, whereas the third design used a square cell layout. The linear interdigitated finger design proved to be more robust, with higher yields than the square cell geometry. It was determined that the square cell design was yield limited due to the impact of wafer bow and total thickness variations on photolithographic accuracy, making the square cell geometry less attractive for large-area 4H-SiC DMOSFETs.

This paper presents the development and demonstration of large-area 10-kV 4H-SiC DMOSFETs that maintain a classically stable low-leakage normally off subthreshold characteristic when operated at les200degC. This is achieved by an additional growth (epitaxial regrowth) of a thin epitaxial layer on top of already implanted p-well regions in conjunction with a N20-based gate oxidation process. Additionally, the design space of the DMOSFET structure was explored using analytical and numerical modeling together with experimental verification. The resulting 0.15-cm2 active 0.43-cm2 die DMOSFET with 10-kV breakdown provides IDS = 8 A at a gate field of 3 MV/cm, along with a subthreshold current at VGS = 0 V that decreases from 1 muA (6.7 muA/cm2) at 25degC to 0.4 muA (2.7 muA/cm2) at 200degC.

In this work a dual-mixed approximation of a nonlinear generalized Stokes problem is studied. The problem is analyzed in Sobolev spaces which arise naturally in the problem formulation. Existence and uniqueness results are given and error estimates are derived. It is shown that both lowest-order and higher-order mixed finite elements are suitable for the approximation method. Numerical experiments that support the theoretical results are presented.

We observed ten M- and X-class main-belt asteroids with the Arecibo Observatory's S-band (12.6 cm) radar. The X-class asteroids were targeted based on their albedos or other properties which suggested they might be M-class. This work brings the total number of main-belt M-class asteroids observed with radar to 14. We find that three of these asteroids have rotation rates significantly different from what was previously reported. Based on their high radar albedo, we find that only four of the fourteen—16 Psyche, 216 Kleopatra, 758 Mancunia, and 785 Zwetana—are almost certainly metallic. 129 Antigone has a moderately high radar albedo and we suggest it may be a CH/CB/Bencubbinite parent body. Three other asteroids, 97 Klotho, 224 Oceana, and 796 Sarita have radar albedos significantly higher than the average main belt asteroid and we cannot rule out a significant metal content for them. Five of our target asteroids, 16 Psyche, 129 Antigone, 135 Hertha, 758 Mancunia, and 785 Zwetana, show variations in their radar albedo with rotation. We can rule out shape and composition in most cases, leaving variations in thickness, porosity, or surface roughness of the regolith to be the most likely causes. With the exception of 129 Antigone, we find no hydrated M-class asteroids (W-class; Rivkin, A.S., Howell, E.S., Lebofsky, L.A., Clark, B.E., Britt, D.T., 2000. Icarus 145, 351–368) to have high radar albedos.

We observed the E-class main-belt Asteroids (MBAs) 44 Nysa and 434 Hungaria with Arecibo Observatory's S-band (12.6 cm) radar. Both asteroids exhibit polarization ratios higher than those measured for any other MBA: Nysa, μ c = 0.50 ± 0.02 and Hungaria, μ c = 0.8 ± 0.1 . This is consistent with the high polarization ratios measured for every E-class near-Earth asteroid (NEA) observed by Benner et al. [Benner, L.A.M., and 10 collegues, 2008. Icarus, submitted for publication] and suggests a common cause. Our estimates of radar albedo are 0.19 ± 0.06 for Nysa and 0.22 ± 0.06 for Hungaria. These values are higher than those of most MBAs and, when combined with their high polarization ratios, suggest that the surface bulk density of both asteroids is high. We model Nysa as an ellipsoid of dimension 113 × 67 × 65 km ( ± 15 % ) giving an effective diameter D eff = 79 ± 10 km , consistent with previous estimates. The echo waveforms are not consistent with a contact binary as suggested by Kaasalainen et al. [Kaasalainen, M., Torppa, J., Piironen, J., 2002. Astron. Astrophys. 383, L19–L22]. We place a constraint on Hungaria's maximum diameter, D max ⩾ 11 km consistent with previous size estimates.