A depletable pool of adenosine in area CA1 of the rat hippocampus

Adenosine plays a major modulatory and neuroprotective role in the mammalian CNS. During cerebral metabolic stress, such as hypoxia or ischemia, the increase in extracellular adenosine inhibits excitatory synaptic transmission onto vulnerable neurons via presynaptic adenosine A1 receptors, thereby reducing the activation of postsynaptic glutamate receptors. Using a combination of extracellular and whole-cell recordings in the CA1 region of hippocampal slices from 12- to 24-d-old rats, we have found that this protective depression of synaptic transmission weakens with repeated exposure to hypoxia, thereby allowing potentially damaging excitation to both persist for longer during oxygen deprivation and recover more rapidly on reoxygenation. This phenomenon is unlikely to involve A1 receptor desensitization or impaired nucleoside transport. Instead, by using the selective A1 antagonist 8-cyclopentyl-1,3-dipropylxanthine and a novel adenosine sensor, we demonstrate that adenosine production is reduced with repeated episodes of hypoxia. Furthermore, this adenosine depletion can be reversed at least partially either by the application of exogenous adenosine, but not by a stable A1 agonist, N6-cyclopentyladenosine, or by endogenous means by prolonged (2 hr) recovery between hypoxic episodes. Given the vital neuroprotective role of adenosine, these findings suggest that depletion of adenosine may underlie the increased neuronal vulnerability to repetitive or secondary hypoxia/ischemia in cerebrovascular disease and head injury

Organizational Resilience: An Exploratory Study on Eldercare and Support Responses to COVID-19

Unexpected events are part of the nature of business for organizations as they operate in a world awash with uncertainty. Businesses must be able to successfully navigate incidents that seek to threaten their viability, create ways to survive, and, at times, take advantage of the opportunities these disruptions bring and thrive, despite these events and their operational effects. Organizational resilience is a dynamic-capability and is also a vital component that supports entities managing their way through disruptive events and, at times, even making the most of them by way of lessons learned and/or the development or enhancement of their organizational capabilities. In this study, I empirically examine, using a conceptual model, how the focus organization moved through the three phases of Organizational Resilience - Anticipation, Coping, and Adaptation - as it responded and adjusted over time to the pandemic. In this study, I extend an earlier study I co-authored focusing on Duchek’s organizational resilience model’s application to the higher education sector to the eldercare sector and examine the processes through which a particular facility moved through each phase of the model as they responded to the COVID-19 pandemic in ways that allowed them to continue operations. I employ a qualitative, exploratory case study approach to examine the levels of support they provided their senior customer base and the pandemic’s implications on both administrators and residents. I extend the nascent body of research on organizational resilience through a business management lens. Practically, I also highlight important lessons that might assist eldercare practitioners in planning for, responding to, and moving through other potentially disruptive events that could significantly threaten and adversely impact their operations so that they might be better positioned to successfully manage future adverse experiences

Investigation of the Coupled Nuclear, Thermal-Hydraulic, and Thermomechanical Response of a Natural Circulation Research Reactor Under Severe Reactivity-Initiated Accident Transients

Research reactors play an important role in higher education, scientific research, and medical radioisotope production around the world. It is thus important to ensure the safety of facility workers and the public. This work presents a new reactor transient analysis code, referred to as Razorback, which computes the coupled reactor kinetics, fuel element heat transfer, fuel element thermal expansion and thermal stress, and thermal-hydraulic response of a natural circulation research reactor. The code was developed for the evaluation of large rapid reactivity addition in research reactors, with an initial focus on the Annular Core Research Reactor (ACRR) at Sandia National Laboratories. Razorback has been validated using ACRR pulse operations, and the simulation results are shown to agree very well with measured reactor data. Razorback is also used to examine the response of a natural circulation research reactor (i.e., the ACRR) to large rapid reactivity additions. The reactor kinetic response, the thermal-hydraulic response of the fuel and coolant, and the thermomechanical response of the fuel element materials are each examined separately. Safety analysis and operational implications are discussed

Manage risk of accidental gene editing of germline

No abstract available

Increasing Engagement and Understanding Using Interactive Planetarium Shows

Despite the popularity of astronomy in first year university, it has lagged behind many other disciplines in implementing modern pedagogical techniques designed to improve student engagement. To address this, over the past several years, the Department of Astronomy and Astrophysics at our university has employed an Audience Response System, the use of online interaction tools such as Twitter and MSN, the introduction of tutorials which include small-group activities, and the use of a planetarium with which we developed both instructor-led and student-led shows. Our goal in this study was to assess the effectiveness of the overall approach on students’ engagement and understanding, with a specific focus on the use of teaching planetaria. Data was collected using quantitative pre and post test questionnaires at three different stages of the course simultaneously during the tutorial and both types of planetarium shows. We also conducted 5 focus groups with approximately 10 participants in each to evaluate their perspectives on the various learning components of the course and how these influenced their engagement. Although analysis is not complete, quantitative data appears to demonstrate no significant knowledge or understanding differences between the various learning experiences. In focus groups, participants claimed to prefer teacher-directed activities such as class lecture and the tutorial to the student-led planetarium show, although several factors qualified these claims. Results are discussed in the context of literature that theorises contemporary schools are reproducing ‘knowledge consumers’ rather than knowledge producers, and the various economic and social factors influencing this

Functional impairment in patients with myotonic dystrophy type 1 can be assessed by an ataxia rating scale (SARA)

Myotonic dystrophy type 1 (DM1) is not characterised by ataxia per se; however, DM1 and ataxia patients show similar disturbances in movement coordination often experiencing walking and balance difficulties, although caused by different underlying pathologies. This study aims to investigate the use of a scale previously described for the assessment and rating of ataxia (SARA) with the hypothesis that it could have utility in DM1 patients as a measure of disease severity and risk of falling. Data from 54 DM1 patients were pulled from the PHENO-DM1 natural history study for analysis. Mean SARA score in the DM1 population was 5.45 relative to the maximum score of eight. A flooring effect (score 0) was observed in mild cases within the sample. Inter-rater and test–retest reliability was high with intraclass coefficients (ICC) of 0.983 and 1.00, respectively. Internal consistency was acceptable as indicated by a Cronbach’s alpha of 0.761. Component analysis revealed two principle components. SARA correlated with: (1) all measures of muscle function tested, including quantitative muscle testing of ankle dorsiflexion (r = −0.584*), the 6 min walk test (r = −0.739*), 10 m walk test (r = 0.741*), and the nine hole peg test (r = 0.602*) and (2) measures of disease severity/burden, such as MIRS (r = 0.718*), MDHI (r = 0.483*), and DM1-Activ (r = −0.749*) (*p < 0.001). The SARA score was predicted by an interaction between modal CTG repeat length and age at sampling (r = 0.678, p = 0.003). A score of eight or above predicted the use of a walking aid with a sensitivity of 100% and a specificity of 85.7%. We suggest that further research is warranted to ascertain whether SARA or components of SARA are useful outcome measures for clinical trials in DM1. As a tool, it can be used for gathering information about disease severity/burden and helping to identify patients in need of a walking aid, and can potentially be applied in both research and healthcare settings

Systematic Floral Anatomy of Pontederiaceae

Twenty species of Pontederiaceae and six species of the outgroup families Haemodoraceae and Philydraceae were investigated with regard to floral anatomy, using standard histological methods and graphic reconstructions. Variation is described in several features, including functional carpel number, the distribution of floral aerenchyma, the presence of unusual floral epithelial cells, the presence, type, and distribution of tannin cells, crystal type and distribution, aspects of placentation, ovule number, number of ovule rows per carpel, and septal nectary presence. In order to better assess character homology, one of these features, placentation, was divided into three discrete characters: septal fusion, placenta position, and placenta evagination. Several of the floral characters were optimized onto a most parsimonious cladogram from a relatively recent study using combined chloroplast DNA data. Associations of character states with specific clades were observed in functional carpel number, aerenchyma distribution, epithelial cell presence, tannin cell distribution, septal nectary presence, and the three redefined aspects of placentation: septal fusion, placenta position, and placenta evagination. These floral data will be valuable in further elucidating relationships in Pontederiaceae in future studies of the group

Measuring Galaxy Environments with Deep Redshift Surveys

We study the applicability of several galaxy environment measures (n^th-nearest-neighbor distance, counts in an aperture, and Voronoi volume) within deep redshift surveys. Mock galaxy catalogs are employed to mimic representative photometric and spectroscopic surveys at high redshift (z ~ 1). We investigate the effects of survey edges, redshift precision, redshift-space distortions, and target selection upon each environment measure. We find that even optimistic photometric redshift errors (\sigma_z = 0.02) smear out the line-of-sight galaxy distribution irretrievably on small scales; this significantly limits the application of photometric redshift surveys to environment studies. Edges and holes in a survey field dramatically affect the estimation of environment, with the impact of edge effects depending upon the adopted environment measure. These edge effects considerably limit the usefulness of smaller survey fields (e.g. the GOODS fields) for studies of galaxy environment. In even the poorest groups and clusters, redshift-space distortions limit the effectiveness of each environment statistic; measuring density in projection (e.g. using counts in a cylindrical aperture or a projected n^th-nearest-neighbor distance measure) significantly improves the accuracy of measures in such over-dense environments. For the DEEP2 Galaxy Redshift Survey, we conclude that among the environment estimators tested the projected n^th-nearest-neighbor distance measure provides the most accurate estimate of local galaxy density over a continuous and broad range of scales.Comment: 17 pages including 16 figures, accepted to Ap