Phosphine Functionalization of GaAs(111)A Surfaces

Phosphorus-functionalized GaAs surfaces have been prepared by exposure of Cl-terminated GaAs(111)A surfaces to triethylphosphine (PEt3) or trichlorophosphine (PCl3), or by the direct functionalization of the native-oxide terminated GaAs(111)A surface with PCl3. The presence of phosphorus on each functionalized surface was confirmed by X-ray photoelectron spectroscopy. High-resolution, soft X-ray photoelectron spectroscopy was used to evaluate the As and Ga 3d regions of such surfaces. On PEt3 treated surfaces, the Ga 3d spectra exhibited a bulk Ga peak as well as peaks that were shifted to 0.35, 0.92 and 1.86 eV higher binding energy. These peaks were assigned to residual Cl-terminated Ga surface sites, surficial Ga2O and surficial Ga2O3, respectively. For PCl3-treated surfaces, the Ga 3d spectra displayed peaks ascribable to bulk Ga(As), Ga2O, and Ga2O3, as well as a peak shifted 0.30 eV to higher binding energy relative to the bulk signal. A peak corresponding to Ga(OH)3, observed on the Cl-terminated surface, was absent from all of the phosphine-functionalized surfaces. After reaction of the Cl-terminated GaAs(111)A surface with PCl3 or PEt3, the As 3d spectral region was free of As oxides and As0. Although native oxide-terminated GaAs surfaces were free of As oxides after reaction with PCl3, such surfaces contained detectable amounts of As0. Photoluminescence measurements indicted that phosphine-functionalized surfaces prepared from Cl-terminated GaAs(111)A surfaces had better electrical properties than the native-oxide capped GaAs(111)A surface, while the native-oxide covered surface treated with PCl3 showed no enhancement in PL intensity

Nutrient Management for Recirculating Hydroponics

Steady-state nutrient management is essential in hydroponic culture. Determination of an appropriate refill solution is attained using the principle of mass balance. Optimizing the ratio of nutrient elements and refill solution concentrations requires an understanding of the ratio of nutrients in tissue to water, which is measured as water use efficiency (WUE). This ratio is then multiplied by the desired concentration of nutrients in leaf tissue to determine the refill solution composition. Deep-flow hydroponics enables constant monitoring of solution parameters and root health. We have achieved a steady-state nitrogen concentration in solution by using an automated pH control system that adds a solution of 50 mM nitric acid and 200 mM ammonium sulfate. The pH remains stable throughout the life cycle as roots release a similar ratio of protons and hydroxide ions to balance uptake of either ammonium or nitrate. Daily monitoring of electrical conductivity (EC) guides adjustment of the refill solution concentration. A variable WUE and water to nutrient uptake ratio among species necessitates custom refill solutions. In our preliminary studies, wheat (Triticum aestivum) has a moderate WUE (3 g L-1) but ceases substantial nutrient uptake late in the lifecycle and the EC thus increases over time, causing nutrient accumulation in solution. Lettuce (Lactuca sativa) also has a moderate WUE (3 g L-1), and the EC of the solution remains stable. Tomato (Solanum lycopersicum) has a high WUE (6 g L-1), causing reduced EC and nutrient solution depletion. Monitoring solution compositions has allowed us to optimize the refill solution and acid addition concentration among species and lifecycle stages

Estimation of Genetic Parameters for Carcass Traits and Their Corresponding Ultrasound Measurements in Crossbred Beef Cattle

Variance parameters including heritabilities, genetic and residual correlations are required for national cattle evaluation. There are huge amounts of data available for estimating such variance parameters for growth traits, but much less data is available for carcass traits. In this study, heritabilities and genetic correlations were estimated using restricted maximum likelihood on carcass weight (CWT), fat thickness (FAT), longissimus muscle area (LMA), marbling score (MRB), birth weight (BW), and ultrasound measurements of fat thickness (UFAT), longissimus muscle area (ULMA) and estimated percentage of intramuscular fat (UIMF) for crossbred cattle with carcass data recorded by the American Simmental Association. A multivariate animal model was fitted using ASREML4 software. The results demonstrate that UIMF measurements provide some useful information for carcass MRB (rg=0.73), but genetic correlations were only moderate between ULMA and LMA (0.56) and were weak between UFAT and FAT (0.38). The implications are that carcass measurements on progeny are the most reliable approach to evaluate carcass traits

Mortality and recruitment of fire-tolerant eucalypts as influenced by wildfire severity and recent prescribed fire

Mixed-species eucalypt forests of temperate Australia are assumed tolerant of most fire regimes based on the impressive capacity of the dominant eucalypts to resprout. However, empirical data to test this assumption are rare, limiting capacity to predict forest tolerance to emerging fire regimes including more frequent severe wildfires and extensive use of prescribed fire. We quantified tree mortality and regeneration in mixed-species eucalypt forests five years after an extensive wildfire that burnt under extreme fire weather. To examine combined site-level effects of wildfire and prescribed fire, our study included factorial replications of three wildfire severities, assessed as crown scorch and understorey consumption shortly after the wildfire (Unburnt, Low, High), and two times since last preceding fire (30 years since any fire). Our data indicate that while most trees survived low-severity wildfire through epicormic resprouting, this capacity was tested by high-severity wildfire. Five years after the wildfire, percentage mortalities of eucalypts in all size intervals from 10 to >70 cm diameter were significantly greater at High severity than Unburnt or Low severity sites, and included the near loss of the 10–20 cm cohort (93% mortality). Prolific seedling regeneration at High severity sites, and unreliable basal resprouting, indicated the importance of seedling recruitment to the resilience of these firetolerant forests. Recent prescribed fire had no clear effect on forest resistance (as tree survival) to wildfire, but decreased site-level resilience (as recruitment) by increasing mortalities of small stems. Our study indicates that high-severity wildfire has the potential to cause transitions to more open, simplified stand structures through increased tree mortality, including disproportionate losses in some size cohorts. Dependence on seedling recruitment could increase vulnerabilities to subsequent fires and future climates, potentially requiring direct management interventions to bolster forest resilience.Australian Governmen

Vision Screening Assessment (VISA) tool: diagnostic accuracy validation of a novel screening tool in detecting visual impairment among stroke survivors

PURPOSE:Screening for visual problems in stroke survivors is not standardised. Visual problems that remain undetected or poorly identified can create unmet needs for stroke survivors. We report the validation of a new Vision Impairment Screening Assessment (VISA) tool intended for use by the stroke team to improve identification of visual impairment in stroke survivors. METHODS:We conducted a prospective case cohort comparative study in four centres to validate the VISA tool against a specialist reference vision assessment. VISA is available in print or as an app (Medicines and Healthcare products Regulatory Agency regulatory approved); these were used equally for two groups. Both VISA and the comprehensive reference vision assessment measured case history, visual acuity, eye alignment, eye movements, visual field and visual inattention. The primary outcome measure was the presence or absence of visual impairment. RESULTS:Two hundred and twenty-one stroke survivors were screened. Specialist reference vision assessment was by experienced orthoptists. Full completion of screening and reference vision assessment was achieved for 201 stroke survivors. VISA print was completed for 101 stroke survivors; VISA app was completed for 100. Sensitivity and specificity of VISA print was 97.67% and 66.67%, respectively. Overall agreement was substantial; K=0.648. Sensitivity and specificity of VISA app was 88.31% and 86.96%, respectively. Overall agreement was substantial; K=0.690. Lowest agreement was found for screening of eye movement and near visual acuity. CONCLUSIONS:This validation study indicates acceptability of VISA for screening of potential visual impairment in stroke survivors. Sensitivity and specificity were high indicating the accuracy of this screening tool. VISA is available in print or as an app allowing versatile uptake across multiple stroke settings

Correction factors for δ 18 O-derived global sea surface temperature reconstructions from diagenetically altered intervals of coral skeletal density banding

Reconstruction of sea surface temperature (SST) from the δ18O and Sr/Ca composition of coral skeletal density banding (CSDB), identified with x-ray diffraction and micro computed tomography, provides invaluable centuries-long records of ocean circulation and climate change. Comparison with age-equivalent instrument measurements of SST over the last 125 years has proven these δ18O-derived SST reconstructions to be generally reliable. However, notable exceptions occur within discrete CSDB stratigraphic intervals that yield δ18O-derived SST underestimates of as much as 9°C with respect to instrument measured SST. Here we combine high-resolution optical and electron microscopy with geochemical modeling to establish correction factors for the impact of marine seafloor physical, chemical, and biological alteration (diagenesis) within these altered intervals of CSDB stratigraphy. Four cores were collected from Porites coral heads across a 4-24 m water depth bathymetric transect at Myrmidon Reef, Great Barrier Reef, Australia. Precise mapping of diagenetic aragonite cementation was completed within CSDB patterns digitally overlaid on 35 petrographic thin sections fully covering 2.1 m of core. The vast majority of core skeletal material exhibited little to no diagenetic aragonite cementation. However, extensive diagenetic alteration was observed within discrete CSDB intervals near the base of the two deeper water Porites heads. This diagenesis serves to modify skeletal density and CSDB stratigraphy in these intervals, as well as structurally reinforce the coral skeleton. Reliable δ18O-based SST correction factors for these diagenetically altered CSDB intervals are established here by applying the percent mixing of diagenetic aragonite cement to a binary mixing model. This approach, with quantitative extents of mixing established with both microscopy and existing globally distributed coral δ18O and Sr/Ca data sets, accurately restores modern and fossil coral δ18O-derived SST records. Results indicate that as little as 5% mixing of diagenetic aragonite cement with original coral skeleton will cause δ18O-based SST anomalies of 0.9°C

A systematic mapping review of the associations between pregnancy intentions and health-related lifestyle behaviours or psychological wellbeing

The aim of this study was to conduct a systematic mapping review of the literature that explored associations of pregnancy intentions with health-related lifestyle behaviours and psychological wellbeing before and during pregnancy. Six databases were searched (May 2017) for papers relating to pregnancy intentions, health-related lifestyle behaviours, and psychological wellbeing. The literature was mapped according to the preconception or pregnancy period; prospective or retrospective variable assessment; and reported lifestyle behaviours and psychological wellbeing outcomes. Of 19,430 retrieved records, 303 studies were eligible. Pregnancy intentions were considered during the preconception period in 103 studies (only 23 assessed prospectively), and during the pregnancy period in 208 studies (141 prospectively). Associations between pregnancy intention and preconception behaviours/psychological wellbeing were primarily reported for supplement use (n = 58) and were lacking for diet/exercise, and psychological factors. For behaviours/psychological wellbeing during pregnancy, associations with pregnancy intention were focused on prenatal care (n = 79), depression (n = 61), and smoking (n = 56) and were lacking for diet/exercise. Only 7 studies assessed pregnancy intentions with a validated tool. Despite a large body of literature, there were several methodological limitations identified, namely assessment of pregnancy intentions with non-validated measures and the reliance on retrospective assessment. Future primary studies are needed to fill gaps in our understanding regarding energy-balance-related behaviours. Future studies (including reviews/meta-analyses) should take care to address the noted limitations to provide a comprehensive and accurate understanding of the relationships between pregnancy intentions and health-related lifestyle behaviours and psychological wellbeing before and during pregnancy

Hormonal responses to cholinergic input are different in humans with and without type 2 diabetes mellitus

<div><p>Peripheral muscarinic acetylcholine receptors regulate insulin and glucagon release in rodents but their importance for similar roles in humans is unclear. Bethanechol, an acetylcholine analogue that does not cross the blood-brain barrier, was used to examine the role of peripheral muscarinic signaling on glucose homeostasis in humans with normal glucose tolerance (NGT; n = 10), impaired glucose tolerance (IGT; n = 11), and type 2 diabetes mellitus (T2DM; n = 9). Subjects received four liquid meal tolerance tests, each with a different dose of oral bethanechol (0, 50, 100, or 150 mg) given 60 min before a meal containing acetaminophen. Plasma pancreatic polypeptide (PP), glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), glucose, glucagon, C-peptide, and acetaminophen concentrations were measured. Insulin secretion rates (ISRs) were calculated from C-peptide levels. Acetaminophen and PP concentrations were surrogate markers for gastric emptying and cholinergic input to islets. The 150 mg dose of bethanechol increased the PP response 2-fold only in the IGT group, amplified GLP-1 release in the IGT and T2DM groups, and augmented the GIP response only in the NGT group. However, bethanechol did not alter ISRs or plasma glucose, glucagon, or acetaminophen concentrations in any group. Prior studies showed infusion of xenin-25, an intestinal peptide, delays gastric emptying and reduces GLP-1 release but not ISRs when normalized to plasma glucose levels. Analysis of archived plasma samples from this study showed xenin-25 amplified postprandial PP responses ~4-fold in subjects with NGT, IGT, and T2DM. Thus, increasing postprandial cholinergic input to islets augments insulin secretion in mice but not humans.</p><p><b><i>Trial Registration</i>:</b> ClinicalTrials.gov <a href="https://clinicaltrials.gov/ct2/show/NCT01434901?term=NCT01434901&rank=1" target="_blank">NCT01434901</a></p></div

An Uncommon Woman: Alison Snow Jones Unleashed!

Alison was like a diamond; truly unique in her brilliant multi-faceted array of talents, brains, passions and skills. Everyone who participated in developing this memorial book commented first on her brilliance. She was a scholar, a top notch statistician, an innovative researcher, a popular blogger about economics and ethics, an exceedingly competent horsewoman and boater, a tremendous cook and baker, someone who loved a good time with others and always a fighter for justice. She was extremely smart, able to form very complex, deep ideas and had an uncommon ability to communicate them easily and effectively to others, including the public