Continuum Variability of Deeply Embedded Protostars as a Probe of Envelope Structure

Stars may be assembled in large growth spurts, however the evidence for this hypothesis is circumstantial. Directly studying the accretion at the earliest phases of stellar growth is challenging because young stars are deeply embedded in optically thick envelopes, which have spectral energy distributions that peak in the far-IR, where observations are difficult. In this paper, we consider the feasibility of detecting accretion outbursts from these younger stars by investigating the timescales for how the protostellar envelope responds to changes in the emission properties of the central source. The envelope heats up in response to an outburst, brightening at all wavelengths and with the emission peak moving to shorter wavelengths. The timescale for this change depends on the time for dust grains to heat and re-emit photons and the time required for the energy to escape the inner, optically-thick portion of the envelope. We find that the dust response time is much shorter than the photon propagation time and thus the timescale over which the emission varies is set by time delays imposed by geometry. These times are hours to days near the peak of the spectral energy distribution and weeks to months in the sub-mm. The ideal location to quickly detect continuum variability is therefore in the mid- to far-IR, near the peak of the spectral energy distribution, where the change in emission amplitude is largest. Searching for variability in sub-mm continuum emission is also feasible, though with a longer time separation and a weaker relationship between the amount of detected emission amplitude and change in central source luminosity. Such observations would constrain accretion histories of protostars and would help to trace the disk/envelope instabilities that lead to stellar growth.Comment: 25 pages, 6 figures, accepted for publication in the Astrophysical Journa

Unmasking the linear behaviour of slow motor adaptation to prolonged convergence

This is the peer reviewed version of the following article: Erkelens, I. M., Thompson, B., & Bobier, W. R. (2016). Unmasking the linear behaviour of slow motor adaptation to prolonged convergence. European Journal of Neuroscience, 43(12), 1553–1560, which has been published in final form at https://doi.org/10.1111/ejn.13240 This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Adaptation to changing environmental demands is central to maintaining optimal motor system function. Current theories suggest that adaptation in both the skeletal-motor and oculomotor systems involves a combination of fast (reflexive) and slow (recalibration) mechanisms. Here we used the oculomotor vergence system as a model to investigate the mechanisms underlying slow motor adaptation. Unlike reaching with the upper limbs, vergence is less susceptible to changes in cognitive strategy that can affect the behaviour of motor adaptation. We tested the hypothesis that mechanisms of slow motor adaptation reflect early neural processing by assessing the linearity of adaptive responses over a large range of stimuli. Using varied disparity stimuli in conflict with accommodation, the slow adaptation of tonic vergence was found to exhibit a linear response whereby the rate (R2 = 0.85, P < 0.0001) and amplitude (R2 = 0.65, P < 0.0001) of the adaptive effects increased proportionally with stimulus amplitude. These results suggest that this slow adaptive mechanism is an early neural process, implying a fundamental physiological nature that is potentially dominated by subcortical and cerebellar substrates.University of Waterloo, NSERC, Canadian Optometric Education Trust Fund (COETF), Ontario QE II GSST Awar

Portfolio Analysis Tool

Portfolio Analysis Tool (PAT) is a Web-based, client/server computer program that helps managers of multiple projects funded by different customers to make decisions regarding investments in those projects. PAT facilitates analysis on a macroscopic level, without distraction by parochial concerns or tactical details of individual projects, so that managers decisions can reflect the broad strategy of their organization. PAT is accessible via almost any Web-browser software. Experts in specific projects can contribute to a broad database that managers can use in analyzing the costs and benefits of all projects, but do not have access for modifying criteria for analyzing projects: access for modifying criteria is limited to managers according to levels of administrative privilege. PAT affords flexibility for modifying criteria for particular "focus areas" so as to enable standardization of criteria among similar projects, thereby making it possible to improve assessments without need to rewrite computer code or to rehire experts, and thereby further reducing the cost of maintaining and upgrading computer code. Information in the PAT database and results of PAT analyses can be incorporated into a variety of ready-made or customizable tabular or graphical displays

Effectiveness of Career and Technology Student Organizations (CTSOs) in Texas

The purpose of this study was to determine the extent to which public school administrators believe that Career and Technology Student Organizations (CTSOs) are providing students the necessary skills for employability and academic success. Objectives focused on whether CTSOs are effective in developing students’ leadership skills, keeping them engaged in school, developing technical skills, and improving academic achievement. School administrators were surveyed via the internet. A 28% response rate was achieved. Ninety-two percent of respondents indicated that their school offered students the opportunity to participate in CTSO activities. Administrators indicated that the FFA was the CTSO that was either most effective or second most effective in teaching leadership skills, keeping students engaged in school, improving technical skills, and improving academic achievement. HOSA and Skills USA also were consistent in being among the top three CTSOs that were effective in providing one of the four characteristics. Considering 80 percent as a benchmark, administrators perceived CTSOs very favorably as being either mostly effective or very effective in meeting students’ needs

Lower Extremity Kinetics in High and Low-Arched Athletes during Landing

Abnormal foot function has been associated with an increased rate of injury in the athletic population. It has been shown that high-arched (HA) and low-arched (LA) athletes experience different injury patterns. These may be the manifestation of different loading and joint torque patterns in HA and LA athletes. It has been shown that HA and LA athletes have unique kinematic and kinetic patterns during running. However, little research has examined ground reaction forces (GRF) and lower extremity joint kinetics in HA and LA athletes during landing tasks. PURPOSE: To examine GRF and knee and ankle joint torques in HA and LA athletes during a landing task. METHODS: Ten HA (age: 20.8±2.5 years; height: 1.62±0.07 m; mass: 58.3±5.4 kg; arch index: 0.386±0.010) and 10 LA (age: 21.1±2.3; height: 1.63±0.07m; mass: 58.9±10.9kg; arch index: 0.259±0.043) female recreational athletes participated in this study. Each subject performed five barefooted drop landing trials from a height of 30 cm. GRFs and three-dimensional (3D) kinematics were recorded simultaneously using a force plate (1200 Hz, AMTI) and 7-camera motion analysis system (240 Hz, Vicon). GRFs and joint torques were calculated using Visual 3D (C-Motion, Inc.) and critical events were determined using custom software. A one-way ANOVA was used to compare group differences with an alpha level of p\u3c0.05. RESULTS: The GRF profiles were similar between the HA and LA athletes. However, HA athletes exhibited a mean eversion moment compared to an inversion moment in LA athletes (HA: -0.05±0.08 Nm/kg; LA: 0.04±0.07 Nm/kg). Additionally, the HA athletes generated greater peak knee external rotation torques (HA: 0.18±0.06 Nm/kg; LA: 0.26±0.08 Nm/kg) compared to LA athletes during the landing task. Knee extension and abduction torques were similar between the two groups in contrast to previous findings. CONCLUSIONS: The greater mean eversion torques exhibited by the HA athletes may be a response to being more inverted throughout the landing task. Increased eccentric contraction of the ankle everters would control eversion during landing. Similarly, the increased knee external rotation torques would act to limit knee internal rotation during landing. These altered kinetic patterns may increase the risk of injury within these groups of athletes

Phenotypic and functional characterization of corneal endothelial cells during in vitro expansion.

The advent of cell culture-based methods for the establishment and expansion of human corneal endothelial cells (CEnC) has provided a source of transplantable corneal endothelium, with a significant potential to challenge the one donor-one recipient paradigm. However, concerns over cell identity remain, and a comprehensive characterization of the cultured CEnC across serial passages has not been performed. To this end, we compared two established CEnC culture methods by assessing the transcriptomic changes that occur during in vitro expansion. In confluent monolayers, low mitogenic culture conditions preserved corneal endothelial cell state identity better than culture in high mitogenic conditions. Expansion by continuous passaging induced replicative cell senescence. Transcriptomic analysis of the senescent phenotype identified a cell senescence signature distinct for CEnC. We identified activation of both classic and new cell signaling pathways that may be targeted to prevent senescence, a significant barrier to realizing the potential clinical utility of in vitro expansion

Initial lists of AMMA-2050 user-relevant climate metrics

AMMA-2050 (African Monsoon Multi-disciplinary Analysis 2050) will improve understanding of how the West African monsoon will be affected by climate change in the coming decades – and help West African societies prepare and adapt

Beta cell death by cell-free DNA and outcome after clinical islet transplantation

Background: Optimizing engraftment and early survival after clinical islet transplantation is critical to long-term function, but there are no reliable, quantifiable measures to assess beta cell death. Circulating cell free DNA (cfDNA) derived from beta cells has been identified as a novel biomarker to detect cell loss, and was recently validated in new-onset type 1 diabetes and in islet transplant patients. Methods: Herein we report beta cell cfDNA measurements after allotransplantation in 37 subjects and the correlation with clinical outcomes. Results: A distinctive peak of cfDNA was observed 1hr after transplantation in 31/37 (83.8%) of subjects. The presence and magnitude of this signal did not correlate with transplant outcome. The 1hr signal represents dead beta cells carried over into the recipient after islet isolation and culture, combined with acute cell death post infusion. Beta cell cfDNA was also detected 24hrs post-transplant (8/37 subjects, 21.6%). This signal was associated with higher 1-month insulin requirements (p=0.04), lower 1-month stimulated C-peptide levels (p=0.01) and overall worse 3-month engraftment, by insulin independence (ROC:AUC=0.70, p=0.03) and Beta 2 score (ROC:AUC=0.77, p=0.006). Conclusions: cfDNA-based estimation of beta cell death 24hrs after islet allotransplantation correlates with clinical outcome and could predict early engraftment.B.G.-L. is supported through the Alberta Innovates :Health Solutions (AIHS) Clinician Fellowship and through the CNTRP. A.P. is supported through AIHS Postgraduate Fellowship and CNTRP. A.M.J.S. is supported through AIHS, and holds a Canada Research Chair in Transplantation Surgery and Regenerative Medicine funded through the Government of Canada. A.M.J.S. is also funded by AIHS Collaborative Research and Innovation Opportunity Team Award and the Diabetes Research Institute Foundation of Canada (DRIFCan). Supported by grants from the Juvenile Diabetes Research Foundation (JDRF) (3-SRA-2014-38-Q-R, to Y.D. and A.M.J.S.), National Institute of Health (NIH) (HIRN grant UC4 DK104216, to Y.D.), DON foundation (Stichting Diabetes Onderzoek Nederland) (to Y.D), the European Union (ELASTISLET project, to Y.D.) and the Kahn foundation (to Y.D., R.S., and B.G.). Supported in part by a grant from The United States Agency for International Development (USAID) American Schools and Hospitals Abroad Program for the upgrading of the Hebrew University sequencing core facilit

T Cell Activation Markers and African Mitochondrial DNA Haplogroups among Non-Hispanic Black Participants in AIDS Clinical Trials Group Study 384

Introduction: Mitochondrial function influences T cell dynamics and is affected by mitochondrial DNA (mtDNA) variation. We previously reported an association between African mtDNA haplogroup L2 and less robust CD4 cell recovery on antiretroviral therapy (ART) in non-Hispanic black ACTG 384 subjects. We explored whether additional T cell parameters in this cohort differed by mtDNA haplogroup. Methods: ACTG 384 randomized ART-naïve subjects to two different nucleoside regimens with efavirenz, nelfinavir, or both. CD4 and CD8 memory and activation markers were available at baseline and week 48 on most subjects. mtDNA sequencing was performed on whole blood DNA, and haplogroups were determined. We studied non-Hispanic black subjects with HIV RNA <400 copies/mL at week 48. Analyses included Wilcoxon ranksum test and linear regression. Results: Data from 104 subjects were included. Major African mtDNA haplogroups included L1 (N = 25), L2 (N = 31), and L3 (N = 32). Baseline age, HIV RNA, and CD4 cells did not differ between L2 and non-L2 haplogroups. Compared to non-L2 haplogroups, L2 subjects had lower baseline activated CD4 cells (median 12% vs. 17%; p = 0.03) and tended toward lower activated CD8 cells (41% vs. 47%; p = 0.06). At 48 weeks of ART, L2 subjects had smaller decreases in activated CD4 cells (−4% vs. −11%; p = 0.01), and smaller CD4 cell increases (+95 vs. +178; p = 0.002). In models adjusting for baseline age, CD4 cells, HIV RNA, and naïve-to-memory CD4 cell ratio, haplogroup L2 was associated with lower baseline (p = 0.04) and 48-week change in (p = 0.01) activated CD4 cells. Conclusions: Among ART-naïve non-Hispanic blacks, mtDNA haplogroup L2 was associated with baseline and 48-week change in T cell activation, and poorer CD4 cell recovery. These data suggest mtDNA variation may influence CD4 T cell dynamics by modulating T cell activation. Further study is needed to replicate these associations and identify mechanisms