Search

Giant icebergs release cold, fresh meltwater as they drift, perturbing the physical conditions of the surface ocean. This study uses satellite‐derived sea surface salinity and temperature measurements to explore the physical impact of supergiant iceberg A68A between September 2020 and June 2021. During A68A's drift through the Scotia Sea in austral spring, gradual but persistent edge‐wasting contributed to a freshening of several psu extending hundreds of kilometers ahead of the iceberg, whilst the cooling signal was more pronounced in the iceberg's wake. The magnitude of the physical perturbation intensified during A68A's breakup near South Georgia. Several large meltwater lenses surrounding the descendant icebergs displayed temperature anomalies of up to −4.5°C, whilst the salinity measurements indicated a surface (skin‐depth) anomaly regularly exceeding order −10 psu. The perturbations stretched at times >1,000 km and persisted for >2 months following A68A's melt in April 2021. Plain Language Summary: Giant icebergs release cold, fresh meltwater as they drift, altering the conditions of the ocean. This study uses sea surface salinity and temperature data collected by satellites to explore these impacts for iceberg A68 between September 2020 and June 2021. During A68A's drift through the Scotia Sea, a freshening of several psu extended hundreds of kilometers ahead of the iceberg, and a pronounced cooling followed behind. The magnitude of the salinity and temperature anomalies intensified when A68A fragmented near South Georgia. The surface ocean displayed temperature anomalies of up to −4.5°C, and salinity anomalies regularly exceeding −10 psu. The perturbation stretched at times >1,000 km and persisted for >2 months following A68A's melt in April 2021. Key Points: Meltwater released from giant iceberg A68A caused large scale freshening and cooling of the surrounding surface oceanIntense temperature and salinity anomalies up to −4.5°C and exceeding −10 psu were recorded during the breakup near South GeorgiaThe freshening and cooling signals stretched at times over 1,000 km and persisted for over 2 months following the iceberg's melt [ABSTRACT FROM AUTHOR]

The Cape mountain zebra (Equus zebra zebra) has recovered from near extinction over more than eight decades. While their numbers have increased, populations remain isolated with low genetic diversity. With more than 75 new populations being founded and more than 4800 extant animals, conservation management strategies are being implemented to mitigate risk of losses in genetic diversity and reproductive fitness. One objective is to identify reproductive characteristics that may improve population growth. Cation channel sperm (CatSper) genes play an important role in hyperactivation of sperm during fertilization. Mutations in these genes lead to reduced fertility and even infertility. Ten male zebras were sampled from a group that were translocated in 2016 in order to found a new population. Single nucleotide polymorphisms (SNPs) were identified in three of the CatSper genes (1 - 3). Lack of variation was observed in all exons, with only four SNPs being identified in the intronic regions in close proximity to exons 1, 2, 7, 8, and 9 of CatSper 1. These results may contribute to the pre-identification of males for new founder populations to ensure population growth and viability, and may be a useful tool for selection against low-producing individuals. [ABSTRACT FROM AUTHOR]

Computational thinking" (CT) is still a relatively new term in the lexicon of learning objectives and science standards. The term was popularized in an essay by Wing, who said, "To reading, writing and arithmetic, we should add computational thinking to every child's analytical ability." Agreeing with this premise, in 2013 the authors of the Next Generation Science Standards (NGSS) included "mathematical and computational thinking" as one of eight essential science and engineering practices that K-12 teachers should strive to develop in their students. There is not yet widespread agreement on the precise definition or implementation of CT, and efforts to assess CT are still maturing, even as more states adopt K-12 computer science standards. In this article we will try to summarize what CT means for a typical introductory (i.e., high school or early college) physics class. This will include a discussion of the ways that instructors may already be incorporating elements of CT in their classes without knowing it. [ABSTRACT FROM AUTHOR]

Incorporating computer programming exercises into introductory physics is a delicate task that involves a number of choices that may have an effect on student learning. We present a "hybrid" approach that speaks to a number of common concerns regarding cognitive load which arise when using programming exercises in introductory physics classes where many students are absolute beginner programmers. This "hybrid" approach provides the student with a highly interactive web-based visualization, not unlike a PhET or Physlet interactive, but importantly the student is shown only the subset of the code where the initial conditions are set and the system variables are evolved. We highlight results from a coding activity that resembles the classic game Asteroids. The goals of this activity are to show how a simple 1D code can be modified into a 2D code, and to reinforce ideas about the relationship between force, velocity, and acceleration vectors. Survey results from four semesters of introductory physics classes at the Ohio State University's Marion campus, in which a high percentage of the students are weak or absolute beginner programmers, provide evidence that most students can complete coding tasks without severe difficulty. Other survey results are promising for future work where conceptual learning will be assessed in a direct way using metrics like the Animated Force Concept Inventory [Dancy and Beichner, Phys. Rev. Spec. Top. Phys. Educ. 2, 010104 (2006)]. The exercise highlighted here and others from our group are available for general use at http://compadre.org/PICUP. [ABSTRACT FROM AUTHOR]

The mechanism for the large Stokes Shifts of InGaN/GaN structures is under debate. Here, we report a systematic study on the Stokes shift of semi-polar (11...2) InGaN/GaN multiple quantum wells (MQWs) with a wide spectral range from green (490 nm) to yellow (590nm) by means of both photoluminescence excitation and time resolved PL measurements in comparison with their c-plane counterparts. The semi-polar samples exhibit a lower Stokes shift than their c-plane counterparts, although they show stronger localization effect than their c-plane counterparts. In the long wavelength region, the Stokes shift of the semi-polar MQWs shows a linear relationship with emission energy, but with a smaller gradient compared with their c-plane counterparts. The time-resolved PL measurements confirm a significant reduction in piezoelectric field of the semi-polar samples compared with the c-plane counterparts. It is suggested that the piezoelectric field induced polarization is the major mechanism for causing the large Stokes shift. The presented results contribute to better understanding of the long standing issue on the mechanism for the large Stokes shift. [ABSTRACT FROM AUTHOR]

By means of a cost effective nanosphere lithography technique, an InGaN/GaN multiple quantum well structure grown on (11-22) semipolar GaN has been fabricated into two dimensional nanorod arrays which form a photonic crystal (PhC) structure. Such a PhC structure demonstrates not only significantly increased emission intensity, but also an enhanced polarization ratio of the emission. This is due to an effective inhibition of the emission in slab modes and then redistribution to the vertical direction, thus minimizing the light scattering processes that lead to randomizing of the optical polarization. The PhC structure is designed based on a standard finite-difference-time-domain simulation, and then optically confirmed by detailed time-resolved photoluminescence measurements. The results presented pave the way for the fabrication of semipolar InGaN/GaN based emitters with both high efficiency and highly polarized emission. [ABSTRACT FROM AUTHOR]

The effect of surface states has been investigated in hybrid organic/inorganic white light emitting structures that employ high efficiency, nearfield non-radiative energy transfer (NRET) coupling. The structures utilize blue emitting InGaN/GaN multiple quantum well (MQW) nanorod arrays to minimize the separation with a yellow emitting F8BT coating. Surface states due to the exposed III-nitride surfaces of the nanostructures are found to reduce the NRET coupling rate. The surface states are passivated by deposition of a silicon nitride layer on the III-nitride nanorod surface leading to reduced surface recombination. A low thickness surface passivation is shown to increase the NRET coupling rate by 4 times compared to an un-passivated hybrid structure. A model is proposed to explain the increased NRET rate for the passivated hybrid structures based on the reduction in surface electron depletion of the passivated InGaN/GaN MQW nanorods surfaces. [ABSTRACT FROM AUTHOR]

Hybrid organic/inorganic white light emitting structures have been fabricated based on a combination of high efficiency InGaN/GaN multiple quantum well (MQW) nanorod arrays and a yellow emitting co-polymer F8BT, leading to a minimised separation between them in order to achieve high efficiency non-radiative energy transfer (NRET). The NRET efficiency has been found 6.7 times higher at room temperature than at 7K. This is attributed to the existence of strong exciton localization the InGaN MQWs, which can undergo thermally activated delocalization at high temperatures. The enhanced NRET efficiency is not only due to the delocalized MQW excitons, but also enhanced by the increased exciton diffusion at higher temperatures. This behaviour highlights the potential for high efficiency NRET in down-conversion hybrid white light emitting diodes operating at room temperature. [ABSTRACT FROM AUTHOR]

Excessive knee abduction loading is a contributing factor to anterior cruciate ligament ( ACL) injury risk. The purpose of this study was to determine whether a double-leg landing training program with real-time visual feedback improves frontal-plane mechanics during double- and single-leg landings. Knee abduction angles and moments and vertical ground reaction forces ( GRF) of 21 recreationally active women were quantified for double- and single-leg landings before and after the training program. This program consisted of two sessions of double-leg jump landings with real-time visual feedback on knee abduction moments for the experimental group and without real-time feedback for the control group. No significant differences were found between training groups. In comparison with pre-training data, peak knee abduction moments decreased 12% post-training for both double- and single-leg landings; whereas peak vertical GRF decreased 8% post-training for double-leg landings only, irrespective of training group. Real-time feedback on knee abduction moments, therefore, did not significantly improve frontal-plane knee mechanics during landings. The effect of the training program on knee abduction moments, however, transferred from the double-leg landings (simple task) to single-leg landings (more complex task). Consequently, ACL injury prevention efforts may not need to focus on complex tasks during which injury occurs. [ABSTRACT FROM AUTHOR]

Lower extremity neuromuscular fatigue purportedly increases anterior cruciate ligament (ACL) injury risk through promotion of extreme landing mechanics. However, the impact of fatigue on muscle groups critical to the landing strategy remains unclear. This study examined the effects of isolated hip rotator and triceps surae fatigue on lower extremity landing biomechanics. Sixteen healthy females (18-22 years) reported for testing on two occasions, with one muscle group fatigued per session. Subjects performed three single-leg landings onto a force platform pre- and post-fatigue, defined as an 80% decrease in peak torque in the targeted muscle group. Hip rotator fatigue was induced via alternating concentric contractions and triceps surae fatigue through concentric plantar flexion contractions on an isokinetic dynamometer. Initial contact (IC) kinematics and peak stance (PS) kinetics and kinematics were analyzed pre- and post-fatigue. Hip rotator fatigue increased IC ( P=0.05) and PS ( P=0.04) hip internal rotation angles. Triceps surae fatigue decreased IC knee flexion ( P=0.01) angle. Isolated hip rotator and triceps surae fatigue each produced modifications in lower limb kinematic parameters viewed as risk factors for ACL injury. These modifications, however, do not appear of sufficient magnitude to compromise ligament integrity, suggesting injury via an integrative lower extremity fatigue mechanism is more likely. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine the extent to which selection for decreased residual feed intake (RFI) affects pork composition and quality. Pigs from the fifth generation of selection for decreased RFI (select) and a randomly selected line (control) were utilized. Two experiments were conducted. In Exp. 1, barrows (22.6 ± 3.9 kg) from select and control lines were paired based on age and BW. The test was conducted in 8 replicates of pairs for the test period of 6 wk. Calpastatin activity and myosin isoforms profile were determined on samples from the LM. Control barrows were heavier (59.1 vs. 55.0 kg; P < 0.01) at the end of the test period. Calpastatin activity was greater (P < 0.01) in LM of select barrows than control barrows. In Exp. 2, composition and quality of gilts (114 kg) from control and select lines were determined. The model included fixed effects of line, slaughter date, melanocortin-4 receptor (MC4R) genotype, barn group, line × slaughter date, genotype × line interactions, a covariate of off-test BW, and sire, pen, and litter fitted as random effects. The select line (n = 80) had 0.043 kg less (P < 0.05) RFI per day than the control line (n = 89). Loin quality and composition were determined at 2 d postmortem. Desmin degradation was measured at 2 and 7 d postmortem. Purge, cook loss, sensory traits, and star probe texture were measured at 7 to 10 d postmortem on cooked chops. Residual correlations between RFI and composition and quality traits were calculated. Compared with the control line, carcasses from the select line tended to have less (P = 0.09) backfat, greater (P < 0.05) loin depth, and greater (P < 0.05) fat free lean. Loin chops from the select line had less (P < 0.01) intramuscular lipid content than loin chops from control line. Significant residual correlations between RFI and both tenderness (r = 0.24, P < 0.01) and star probe (r = -0.26, P < 0.01) were identified. Selection for decreased RFI has the potential to improve carcass composition with few effects on pH and water-holding capacity. However, decreased RFI could negatively affect tenderness and texture because of decreased lipid content and decreased postmortem protein degradation. [ABSTRACT FROM AUTHOR]

The hepatitis C virus (HCV) 3′-untranslated region (UTR) and negative-strand RNA sequences contribute cis-acting functions essential to viral RNA replication. Although efficient suppression of HCV replicon RNA in cell culture has been demonstrated with small interfering RNAs (siRNAs) directed against various sequences in the 5′ UTR and coding regions, data regarding siRNA targeting of the 3′ UTR have been lacking. Furthermore, it has not been definitively shown whether the active constructs, identified to date, exert their effect exclusively via suppression of the replicon positive strand, negative strand or some combination of both strands. In the present study, we assayed inhibitory activity of various siRNAs targeting the 3′ UTR by transient transfection in a subgenomic replicon cell culture model. A survey of 13 candidate target sites in the 3′-UTR X sequence indicated a uniformly low activity of siRNA constructs against the steady-state level of replicon. In contrast, the majority of these same siRNAs exhibited high activity against HCV X sequences of either polarity when these targets were presented in the context of a mammalian polymerase II mRNA transcript. Transfection of siRNAs directed against other regions of the replicon revealed differences in the magnitude of inhibitory effects against positive-strand and negative-strand target sites. Strand preference of siRNA activity was further demonstrated through the introduction of base-pair-destabilizing mutations that promote strand-specific targeting. The results suggest that the HCV positive-strand 5′ UTR and coding region are efficiently and directly targeted by siRNA, whereas the 3′ UTR and the entire negative strand are relatively resistant to RNA interference. [ABSTRACT FROM AUTHOR]

Introduction Previous studies reported that the radiation exposure to the hands of orthopaedic surgeons was far below the acceptable limit. However, the risk could have been underestimated as some factors were overlooked, namely monitoring trainees during average workload, placing dosimeters over the most susceptible locations, measuring the cumulative dosage of radiation and considering the dose limit for non-classified workers. Materials and methods We performed a prospective study in two centres to estimate the radiation dose to the hands of two consultant trauma surgeons and two trainees (one assisting and one operating) while performing 47 fluoroscopy-assisted procedures. We used validated thermoluminescent dosimeters (TLDs) rings and fingerstalls for monitoring the cumulative dosage. Results Trainees were at higher risk while performing intramedullary nailing and during assistance. Higher radiation doses were recorded from dominant index fingers and particularly fingertips. Conclusion The risk of radiation exposure appears to be higher than previously reported. Fingertips are more susceptible to radiation exposure and should therefore be monitored in forthcoming studies. [ABSTRACT FROM AUTHOR]

Summary 1. Growth rates of immature invertebrates can be of profound importance to subsequent reproductive success in the adult stage. If diet selection in herbivores is a principal means of maximising growth and rate of development, individuals should select food of the highest quality. 2. If disparities are found between performance and preference, these may be the result of individuals balancing nutritional gain against other demands on their behaviour, such as a need for shelter. The responses of the crane-fly herbivore Tipula montana Curtis (Diptera: Tipulidae) to a range of moss genera from an upland environment were investigated to determine whether diet selection was determined by food quality alone, as measured by its effect on larval growth and survival. 3. Larvae were reared individually on single moss genus diets, and their growth, development, and survival were measured. Each of the mosses supported growth and development although the mean weights achieved differed by a factor of two between food genera. In two-choice preference experiments, individuals broadly chose bryophyte foods as expected from their quality. One notable exception was the moss Pleurozium schreberi, which gave the best growth performance but was among the least preferred. 4. The two methods of assessing preference gave different results: observations of larvae showed relatively greater selection for dense mosses than faecal pellet analysis. A strong dietary preference for an angiosperm, the sedge Carex bigelowii, over all mosses supported the interpretation that crane-fly larvae benefit from bryophytes as a refuge, and that this factor may override dietary quality. [ABSTRACT FROM AUTHOR]

Background Inflammatory mediators are released after trauma and may be related to the pathogenesis of sepsis. A prospective combined study of the pattern of release of an inflammatory mediator, interleukin (IL) 6, leucocyte activation (polymorphonuclear leucocyte (PMN) CD11b receptor expression and plasma elastase-α1 proteinase inhibitor complex (E–α1PI)) and soluble endothelial adhesion molecule expression (soluble E-selectin (sE-selectin) and soluble intracellular adhesion molecule 1 (sICAM-1)) was performed in patients suffering blunt trauma without adult respiratory distress syndrome (ARDS) or multiple organ failure syndrome (MOFS). Methods Thirty-one patients with a mean Injury Severity Score (ISS) of 14 (range 9–57) were studied. Venous blood samples were collected within 6 h of injury and then at 1, 3, 5 and 7 days. Leucocyte CD11b expression was quantified by flow cytometry. Serum IL-6, plasma E–α1PI, sE-selectin and sICAM-1 were measured by enzyme-linked immunosorbent assay. Results Serum IL-6, CD11b expression and E–α1PI levels were significantly raised above control values (P<0·0001) on admission, slowly returning towards control values over the study period (median IL-6, 140 pg/ml versus undetectable; CD11b, 14·8 versus 6·4 mean channel fluorescence units; E–α1 PI, 208 versus 52 μg/l). The sICAM-1 level rose to a median of 539 ng/ml at 5 days (control 243 ng/ml). The median sE-selectin level also progressively increased to a maximum level of 80 ng/ml at 5 days (control 49 ng/ml). Eleven patients developed postoperative sepsis. Significant differences in CD11b expression were seen at days 3, 5 and 7 and in E–α1 PI at 6 h, 24 h and 3 days in patients who subsequently developed sepsis (P<0·05). Severe injury (ISS 16 or greater) was associated with significantly greater responses in these... [ABSTRACT FROM AUTHOR]

A survey for the presence of Listeria monocytogenes in hospital sandwiches was carried out in Wales, United Kingdom, between October 2005 and March 2006. The main aim of the survey was to establish the baseline rate of L. monocytogenes in hospital sandwiches after an outbreak of listeriosis among hospital patients in 2004 was epidemiologically linked to the consumption of contaminated sandwiches. The overall positive rate found in hospital sandwiches was 2.84% for enriched culture and 0.21% for direct counts. The unsatisfactory rate (>100 CFU/g) for hospital sandwiches was 0.1%. The conclusion was that hospital sandwiches generally presented a low hazard to consumers. In addition to establishing the overall baseline and the unsatisfactory rates in hospital sandwiches in Wales for this period, the study compared the rates found in hospital sandwiches with the rates found in sandwiches simultaneously sampled from general retailers. The aim of this part of the study was to compare the relative rates associated with hospital and retail sandwiches to ascertain if there were any differences in the positive rate. The conclusion of this part of the survey was that there was not a statistically significant difference in rates between sandwiches sampled from hospitals and those sampled from general retailers. [ABSTRACT FROM AUTHOR]

Electroluminescence polarization measurements have been performed on a series of semi-polar InGaN light emitting diodes (LEDs) grown on semi-polar (11–22) templates with a high crystal quality. The emission wavelengths of these LEDs cover a wide spectral region from 443 to 555 nm. A systematic study has been carried out in order to investigate the influence of both indium content and injection current on polarization properties, where a clear polarization switching at approximately 470 nm has been observed. The shortest wavelength LED (443 nm) exhibits a positive 0.15 polarization degree, while the longest wavelength LED (555 nm) shows a negative −0.33 polarization degree. All the longer wavelength LEDs with an emission wavelength above 470 nm exhibit negative polarization degrees, and they further demonstrate that the dependence of polarization degree on injection current enhances with increasing emission wavelength. Moreover, the absolute value of the polarization degree decreases with increasing injection current. In contrast, the polarization degree of the 443 nm blue LED remains constant with changing injection current. This discrepancy can be attributed to a significant difference in the density of states (DOS) of the valence subbands. [ABSTRACT FROM AUTHOR]

Highly polarised white light emission from a hybrid organic/inorganic device has been achieved. The hybrid devices are fabricated by means of combining blue InGaN-based multiple quantum wells (MQWs) with a one-dimensional (1D) grating structure and down-conversion F8BT yellow light emitting polymer. The 1D grating structure converts the blue emission from unpolarised to highly polarised; Highly polarised yellow emission has been achieved from the F8BT polymer filled and aligned along the periodic nano-channels of the grating structure as a result of enhanced nano-confinement. Optical polarization measurements show that our device demonstrates a polarization degree of up to 43% for the smallest nano-channel width. Furthermore, the hybrid device with such a grating structure allows us to achieve an optimum relative orientation between the dipoles in the donor (i.e., InGaN/GaN MQWs) and the diploes in the acceptor (i.e., the F8BT), maximizing the efficiency of non-radiative energy transfer (NRET) between the donor and the acceptor. Time-resolved micro photoluminescence measurements show a 2.5 times enhancement in the NRET efficiency, giving a maximal NRET efficiency of 90%. It is worth highlighting that the approach developed paves the way for the fabrication of highly polarized white light emitters. [ABSTRACT FROM AUTHOR]

The coordination of food sampling activities across Wales, a part of the United Kingdom with a population of approximately 3 million, led to the establishment in 1995 of a coordinated food-sampling program designed to monitor on a long-term basis the microbiological quality and safety of specific ready-to-eat products. This surveillance system has been ongoing for 9 years and has generated a database of microbiological and associated demographic results for 15,228 ready-to-eat food samples. The food types that had the poorest overall results were sliced meats, unsliced poultry, sandwiches made without salad, and cakes made without dairy cream. For all food types, the overall unsatisfactory rate was 17% for aerobic colony counts, 1.6% for Escherichia coli, and 0.5% for Listeria spp. Overall unsatisfactory or unacceptable rates for pathogens such as Clostridium perfringens, Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus were all below 0.5%. No Campylobacter-positive samples and only one Salmonella-positive sample were found. The analysis of the results show that the ready-to-eat food types sampled over the 9 years of the program were generally of good microbiological quality when compared with current United Kingdom guidelines. The information contained in the database provides a baseline measurement of the microbial quality of a variety of ready-to-eat foods and allows environmental health officers and food microbiologists to generate hypotheses for targeted surveys or research work. [ABSTRACT FROM AUTHOR]

While it is clear that Type Ia supernovae (SNe) are the result of thermonuclear explosions in C/O white dwarfs (WDs), a great deal remains uncertain about the binary companion that facilitates the explosive disruption of the WD. Here, we present a comprehensive analysis of a large, unique data set of 127 SNe Ia with exquisite coverage by the Zwicky Transient Facility (ZTF). High-cadence (six observations per night) ZTF observations allow us to measure the SN rise time and examine its initial evolution. We develop a Bayesian framework to model the early rise as a power law in time, which enables the inclusion of priors in our model. For a volume-limited subset of normal SNe Ia, we find that the mean power-law index is consistent with 2 in the rZTF-band (), as expected in the expanding fireball model. There are, however, individual SNe that are clearly inconsistent with. We estimate a mean rise time of 18.9 days (with a range extending from ∼15 to 22 days), though this is subject to the adopted prior. We identify an important, previously unknown, bias whereby the rise times for higher-redshift SNe within a flux-limited survey are systematically underestimated. This effect can be partially alleviated if the power-law index is fixed to α = 2, in which case we estimate a mean rise time of 21.7 days (with a range from ∼18 to 23 days). The sample includes a handful of rare and peculiar SNe Ia. Finally, we conclude with a discussion of lessons learned from the ZTF sample that can eventually be applied to observations from the Vera C. Rubin Observatory. [ABSTRACT FROM AUTHOR]

A survey of the Salmonella and Campylobacter contamination of raw, whole chickens available to consumers in Wales was performed between March and December 2003. In total, 736 samples were taken, and overall contamination rates of 73.1% for Campylobacter and 5.7% for Salmonella were found. This survey follows a survey performed during 2001 to 2002 by Welsh local authorities and the National Public Health Service for Wales that established updated baseline rates for both pathogens in raw, whole chicken available to consumers in Wales. This survey indicated no difference in Campylobacter rates between fresh and frozen samples or between samples taken from retailers and local butchers, but significant differences existed in Salmonella rates between fresh and frozen samples and between those sampled from retailers and butchers, with frozen chickens and samples taken from retailers having significantly higher rates. However, the difference in Salmonella isolation rate between retailers and butchers was found to be due to the differences in the proportions of fresh and frozen chickens sampled from these locations, with a significantly higher number of frozen chickens (with a higher Salmonella rate) being sampled from retailers. [ABSTRACT FROM AUTHOR]

We demonstrate a great improvement in the crystal quality of our semi-polar (11-22) GaN overgrown on regularly arrayed micro-rod templates fabricated using a combination of industry-matched photolithography and dry-etching techniques. As a result of our micro-rod configuration specially designed, an intrinsic issue on the anisotropic growth rate which is a great challenge in conventional overgrowth technique for semi-polar GaN has been resolved. Transmission electron microscopy measurements show a different mechanism of defect reduction from conventional overgrowth techniques and also demonstrate major advantages of our approach. The dislocations existing in the GaN micro-rods are effectively blocked by both a SiO2 mask on the top of each GaN micro-rod and lateral growth along the c-direction, where the growth rate along the c-direction is faster than that along any other direction. Basal stacking faults (BSFs) are also effectively impeded, leading to a distribution of BSF-free regions periodically spaced by BSF regions along the [-1-123] direction, in which high and low BSF density areas further show a periodic distribution along the [1-100] direction. Furthermore, a defect reduction model is proposed for further improvement in the crystalline quality of overgrown (11-22) GaN on sapphire. [ABSTRACT FROM AUTHOR]

We report the manipulation of nitrogen vacancy (NV) spins in diamond when a nearby ferrimagnetic insulator, yttrium iron garnet, is driven into precession. The change in NV spin polarization, as measured by changes in photoluminescence, is comparable in magnitude to that from conventional optically detected magnetic resonance, but relies on a distinct mechanism as it occurs at a microwave frequency far away from the magnetic resonance frequency of the NV spin. This observation presents an approach to transferring ferromagnetic spin information into a paramagnet and then transducing the response into a robust optical signal. It also opens strategies for studying ferromagnetism and spin transport at the nanoscale. [ABSTRACT FROM AUTHOR]

Weak gravitational lensing observations are a key science driver for the NASA Wide Field Infrared Survey Telescope (WFIRST). To validate the performance of the WFIRST infrared detectors, we have performed a laboratory emulation of weak gravitational lensing measurements. Our experiments used a custom precision projector system to image a target mask composed of a grid of pinholes, emulating stellar point sources, onto a 1.7 μm cut-off Teledyne HgCdTe/H2RG detector. We used a 0.88 μm LED illumination source and f=22 pupil stop to produce undersampled point spread functions similar to those expected from WFIRST.We also emulated the WFIRST image reconstruction strategy, using the image combination (IMCOM) algorithm to derive oversampled images from dithered, undersampled input images. We created shear maps for this data and computed shear correlation functions to mimic a real weak lensing analysis. After removing only second-order polynomial fits to the shear maps, we found that the correlation functions could be reduced to O(10-6). This places a conservative upper limit on the detector-induced bias to the correlation function (under our test conditions). This bias is two orders of magnitude lower than the expected weak lensing signal. Restricted to scales relevant to dark energy analyses (sky separations >0:50), the bias is O(10-7)--comparable to the requirement for future weak lensing missions to avoid biasing cosmological parameter estimates. Our experiment will need to be upgraded and repeated under different configurations to fully characterize the shape measurement performance of WFIRST IR detectors. [ABSTRACT FROM AUTHOR]

The effect of rowing ergometer design upon power delivery and coordination patterns of the rowing stroke was analyzed for 14 elite rowers. Rowers were tested in three ergometer conditions: the fixed stretcher Concept2c ergometer, the Concept2c ergometer mounted on sliding rails, and the sliding stretcher Row Perfect ergometer. Ergometers were instrumented to measure the external force generated at the handle and the foot stretcher and a nine-segment inverse dynamics model used to calculate joint and overall power delivery. Peak power generation and absorption at the knee joint was significantly greater, and total power delivered to the ergometer delayed on the fixed stretcher ergometer when compared to the sliding stretcher ergometers. No differences were found in the mechanical energy delivered to the handle of the three ergometers; however, greater joint mechanical energy production of the lower limb reduced mechanical efficiency when rowing the Concept2c fixed ergometer. The fixed foot stretcher on the Concept2c fixed ergometer acts to increase the inertial forces that the rower must overcome at the catch, increasing the moment and power output at the knee, and affecting the coordination pattern during the recovery phase. [ABSTRACT FROM AUTHOR]

ABSTRACT Despite its utility in exploring possible spatial variations in the stellar populations in galaxies, infrared surface photometry of low-luminosity dwarf elliptical (dE) galaxies is generally lacking, due to the technical difficulties in observing low surface brightness objects against the bright infrared sky. Here we attempt to remedy this shortfall to some extent by presenting K-band photometry at arcsecond resolution, including radial profiles, 1D and 2D model fits and the quantification of nuclear components, for a small sample of dE galaxies, with absolute magnitudes M B≃−15 to −13, in the Fornax Cluster. In the second part of the paper, we explore the comparison of these data with corresponding optical observations and attempt to interpret this in terms of stellar population models and their radial trends. A significant range of global optical-infrared colours is present in our sample, but radial colour gradients in the galaxies are usually small. However, while the nuclear regions tend to be bluer in optical colours, they are systematically redder than the surrounding galaxy in ( R− K). The stellar population modelling suggests that these colour differences are probably an effect of both higher metallicity and younger age in the nuclei. Excluding the nuclear regions, the global colour profiles typically change in the same direction, again indicating older, more metal-poor stellar populations in the outskirts of the galaxies. [ABSTRACT FROM AUTHOR]

Diabet. Med. 27, 812–822 (2010) Aims For selected individuals with complex Type 1 diabetes, pancreatic islet transplantation (IT) offers the potential of excellent glycaemic control without significant hypoglycaemia, balanced by the need for ongoing systemic immunosuppression. Increasingly, patient-reported outcomes (PROs) are considered alongside biomedical outcomes as a measure of transplant success. PROs in IT have not previously been compared directly with the closest alternate treatment option, pancreas transplant alone (PTA) or pancreas after kidney (PAK). Methods We used a Population, Intervention, Comparisons, Outcomes (PICO) strategy to search Scopus and screened 314 references for inclusion. Results Twelve studies [including PRO assessment of PAK, PTA, islet-after kidney (IAK) and islet transplant alone (ITA); n = 7–205] used a total of nine specified and two unspecified PRO measures. Results were mixed but identified some benefits which remained apparent up to 36 months post-transplant, including improvements in fear of hypoglycaemia, as well as some aspects of diabetes-specific quality of life (QoL) and general health status. Negative outcomes included short-term pain associated with the procedure, immunosuppressant side effects and depressed mood associated with loss of graft function. Conclusions The mixed results may be attributable to limited sample sizes. Also, some PRO measures may lack sensitivity to detect actual changes, as they exclude issues and domains of life likely to be important for QoL post-transplantation and when patients may no longer perceive themselves to have diabetes. Thus, the full impact of islet/pancreas transplantation (alone or after kidney) on QoL is unknown. Furthermore, no studies have assessed patient satisfaction, which may highlight further advantages and disadvantages of transplantation. [ABSTRACT FROM AUTHOR]

Objectives: In this study, the effects of temporal changes in unanticipated (UN) prelanding stimuli on lower limb biomechanics and the impact of sex and limb dominance on these variables during single-leg landings were determined. It was hypothesised that reductions in the time of prelanding UN stimuli, female sex, and the non-dominant limb would significantly increase high-risk landing biomechanics during UN jump landings. Methods: 26 (13 men and 13 women) had initial contact (IC) and peak stance (0-50%) phase (PS) lower limb joint kinematics and kinetics quantified during anticipated (AN) and UN single-leg (left and right) landings. Postlanding jump direction was governed via one of two randomly ordered light stimuli, presented either before initiation of the jump (AN), or 600 ms (UN1), 500 ms (UN2) or 400 ms (UN3) immediately before ground contact. Results: Statistically significant (p<0.05) differences in IC hip posture and PS hip and knee internal rotation moments occurred in UN compared with AN landings. Differences were not observed, however, among UN conditions for any biomechanical comparisons. Significant (p<0.05) differences in specific IC and PS hip and knee postures and loads occurred between sexes and limbs. Neither of these factors, however, influenced movement condition effects. Conclusion: UN landings induce modifications in landing biomechanics that may increase anterior cruciate ligament injury risk in both men and women. These modifications, however, do not appear overly sensitive to the timing of the UN stimulus, at least within a temporal range affording a successful movement response. Expanding UN training to include even shorter stimulus-response times may promote the additional central control adaptations necessary to manoeuvre safely within the random sports setting. [ABSTRACT FROM AUTHOR]

Background Non-adherence to 5-aminosalicylic acid (5-ASA) medication can limit the established benefits of this therapy in ulcerative colitis (UC). Aim To determine rates and predictors of non-adherence to 5-ASA therapy in UC patients. Methods Medication adherence was assessed using self-report data and urinary drug excretion measurements. Participants completed a study-specific questionnaire and two validated questionnaires: Beliefs about Medicine Questionnaire (BMQ)-Specific and Satisfaction with Information about Medicines Scale. Results A total of 169 participants provided self-report adherence data; 151 also provided urine samples. Adherence rates were 111/151 (68%) according to self-report and 90/151 (60%) according to urine analysis, but the two measures were not correlated (χ2 = 0.12, P = 0.725). Logistic regression identified a significant association between self-reported non-adherence and younger age [odds ratio (OR) for increased age 0.954, 95% confidence interval (CI) 0.932–0.976] and also doubts about personal need for medication (OR for BMQ – Specific Necessity scores 0.578, 95% CI 0.366–0.913). For non-adherence based on urine analysis, only South Asian ethnicity was independently associated with non-adherence (OR 2.940, 95% CI 1.303–6.638). Conclusions Our observations confirm the difficulty of accurately assessing medication adherence. Nonmodifiable (younger age, South Asian ethnicity) and potentially modifiable (medication beliefs) predictors of non-adherence were identified. [ABSTRACT FROM AUTHOR]

Systemic administration of islet-derived antigens has been shown to protect against diabetes in the non-obese diabetic (NOD) mouse by the induction of antigen-specific regulatory T cells. Bystander regulation to related and unrelated islet-derived antigens (intramolecular and intermolecular recognition) in this context is recognized. We tested if intranasal administration of glutamic acid decarboxylase 65 (GAD 65)-derived peptides could protect against both autoimmune and, through bystander regulation, alloimmune responses in a NOD mouse model. Spontaneously diabetic female NOD mice underwent islet transplantation from either C57Bl/6 or NOD islet donors. Islet recipients were treated with intranasal GAD 65-derived peptides or control (ovalbumin) peptide pre- and post-transplantation. In-vitro analysis of the effect of inhalation was defined using lymph node proliferation assays and supernatant analysis for cytokines. GAD 65-derived peptide inhalation resulted in significant protection against recurrent autoimmune disease, with the generation of an interleukin (IL)-10-producing immune phenotype in a syngeneic islet transplant model. This phenotype, however, was not robust enough to protect against alloimmune responses. Inhalation of GAD-derived peptides induces an immunoregulatory response that protects against recurrent autoimmune, but not alloimmune responses in the NOD mouse. [ABSTRACT FROM AUTHOR]

The Fornax Cluster Spectroscopic Survey (FCSS) project utilizes the Two-degree Field (2dF) multi-object spectrograph on the Anglo-Australian Telescope (AAT). Its aim is to obtain spectra for a complete sample of all 14 000 objects with 16.5 ≤ b[sub j] ≤ 19.7 irrespective of their morphology in a 12 deg² area centred on the Fornax cluster. A sample of 24 Fornax cluster members has been identified from the first 2dF field (3.1 deg² in area) to be completed. This is the first complete sample of cluster objects of known distance with well-defined selection limits. Nineteen of the galaxies (with -15.8 < M[sub B] < - 12.7) appear to be conventional dwarf elliptical (dE) or dwarf SO (dSO) galaxies. The other five objects (with - 13.6 < M[sub B] < - 11.3) are those galaxies which were described recently by Drinkwater et al. and labelled 'ultracompact dwarfs' (UCDs). A major result is that the conventional dwarfs all have scale sizes α ... 3 arcsec (...300 pc). This apparent minimum scale size implies an equivalent minimum luminosity for a dwarf of a given surface brightness. This produces a limit on their distribution in the magnitude-surface brightness plane, such that we do not observe des with high surface brightnesses but faint absolute magnitudes. Above this observed minimum scale size of 3 arcsec, the des and dS0s fill the whole area of the magnitude-surface brightness plane sampled by our selection limits. The observed correlation between magnitude and surface brightness noted by several recent studies of brighter galaxies is not seen with our fainter cluster sample. A comparison of our results with the Fornax Cluster Catalog (FCC) of Ferguson illustrates that attempts to determine cluster membership solely on the basis of observed morphology can produce significant errors. The FCC identified 17 of the 24 FCSS sample (i.e. 71 per cent) as being 'cluster' members, in particular missing all five of the UCDs. The FCC also suffers from... [ABSTRACT FROM AUTHOR]