332 research outputs found

    STUDENT PERCEPTION OF PREPAREDNESS IN THE MIDST OF COVID-19: A SNAPSHOT FROM FIRST YEAR CHEMISTRY STUDENTS

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    The transition from high school to tertiary education can present many challenges for students. First year students must navigate new formal curricular, societal norms, physical environments, and support networks. An important factor for a successful transition from secondary to tertiary education is student preparedness. This transition period was thrown on its head due to the global challenges that the COVID-19 pandemic presented in 2020. The aim of this research was to identify and examine the perceptions of preparedness of first-year chemistry students, and if these perceptions were significantly impacted by COVID-19. Surveys were deployed to a first-year chemistry cohort at both the start and the end of semester, and follow up focus groups conducted after the conclusion of the semester. Results indicate that students’ perceptions of preparedness for studying chemistry increased over the course of the semester, however for studying at university in general the perception of preparedness decreased. The absence of in-person laboratory practicals was found to be a great concern for students, along with factors previously found to impact students’ perceptions. Reflections and findings of the students’ experiences will be presented from the first semester of 2020 delivered online through emergency remote teaching and learning

    Spring Calving Suckler Beef Systems: Influence of Grassland Management System on Herbage Availability, Utilisation, Quality and Cow and Calf Performance to Weaning

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    Suckler beef systems in Ireland are primarily based on grass. Suckler systems vary in intensity but many operate low input systems and participate in REPS (Rural Environmental Protection Scheme). As there is a considerable cost associated with second-cut silage this research compared a two-cut system with a simplified low input one-cut system

    Nle4DPhe7α-Melanocyte-Stimulating Hormone Increases the Eumelanin:Phaeomelanin Ratio in Cultured Human Melanocytes

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    In mammals, melanin exists in two chemically distinct forms: the red-yellow phaeomelanin and the brown-black eumelanin. Although administration of the pigmentary hormone α-melanocyte-stimulating hormone (αMSH) and its synthetic analogue Nle4DPhe7αMSH induces skin darkening in man, the increases in melanogenesis in cultured human melanocytes in response to these peptides are relatively small, However, it is possible that MSH affects the eumelanin:phaeomelanin ratio rather titan total cellular melanin. Thus, this study examined the specific effects of Nle4DPhe7αMSH on the two melanins in cultured human melanocytes, quantifying eumelanin and phaeomelanin by hign performance liquid chromatography. Nle4DPhe7αMSH induced significant increases in the eumelanin content of these cells while having lesser and varied effects on the levels of phaeomelanin. As a consequences the eumelanin: phaeomelanin ratio was increased in every culture. These results demonstrate that Nle4DPhe7αMSH affects melanin type in human melanocytes and suggest a possible mechanism by which this peptide induces skin darkening in man

    Preliminary age-based life history characteristics of the dogtooth tuna, Gymnosarda unicolor (Ruppell, 1838), in the southwest Pacific Ocean

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    Dogtooth tuna, Gymnosarda unicolor were sampled off the east coast of Australia (southwest Pacific Ocean) from 2007 to 2012. Ages were determined by examining thin transverse sections of their sagittal otoliths and were based on counts of alternating opaque and translucent zones (annual growth increments). Growth was rapid during the first year of life, after which growth in length was much reduced. Parameters of the constrained von Bertalanffy growth function (fork length-at-age) were L∞ = 1164.77 (mm, FL) and K = 0.44 year−1. Preliminary estimates of longevity indicate a maximum observed age of at least 20 years. There was a high degree of variation in the observed length and age of sexual maturity for G. unicolor. Despite this variation, the size at 50% maturity for female G. unicolor estimated in this study was 713 mm FL (<2 years of age). The diet of G. unicolor is very broad and covers a range of fish species. The life history characteristics of G. unicolor overall, indicate that this species may be somewhat resilient to fishing. However, reports of localised depletions, in association with heavy targeting by sports fishers, low effective population sizes and patchy recruitment indicate that this species is particularly vulnerable to overfishing

    Exploring Spatial Patterns of Virginia Tornadoes Using Kernel Density and Space-Time Cube Analysis (1960-2019)

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    This study evaluates the spatial-temporal patterns in Virginia tornadoes using the National Weather Service Storm Prediction Center’s Severe Weather GIS (SVRGIS) database. In addition to descriptive statistics, the analysis employs Kernel Density Estimation for spatial pattern analysis and space-time cubes to visualize the spatiotemporal frequency of tornadoes and potential trends. Most of the 726 tornadoes between 1960–2019 occurred in Eastern Virginia, along the Piedmont and Coastal Plain. Consistent with other literature, both the number of tornadoes and the tornado days have increased in Virginia. While 80% of the tornadoes occurred during the warm season, tornadoes did occur during each month including two deadly tornadoes in January and February. Over the 60-year period, a total of 28 people were killed in the Commonwealth. Most tornado activity took place in the afternoon and early evening hours drawing attention to the temporal variability of risk and vulnerability. Spatial analysis results identify significant, non-random clusters of tornado activity and increasing temporal frequency. While this study improves weather-related literacy and addresses a need in the Commonwealth, more research is necessary to further evaluate the synoptic and mesoscale mechanisms of Virginia tornadoes

    CHIMERA: a wide-field, multi-colour, high-speed photometer at the prime focus of the Hale telescope

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    The Caltech HIgh-speed Multi-colour camERA (CHIMERA) is a new instrument that has been developed for use at the prime focus of the Hale 200-inch telescope. Simultaneous optical imaging in two bands is enabled by a dichroic beam splitter centred at 567 nm, with Sloan u′ and g′ bands available on the blue arm and Sloan r′, i′ and z_s bands available on the red arm. Additional narrow-band filters will also become available as required. An electron multiplying CCD (EMCCD) detector is employed for both optical channels, each capable of simultaneously delivering sub-electron effective read noise under multiplication gain and frame rates of up to 26 fps full frame (several 1000 fps windowed), over a fully corrected 5 × 5 arcmin field of view. CHIMERA was primarily developed to enable the characterization of the size distribution of sub-km Kuiper Belt Objects via stellar occultation, a science case that motivates the frame-rate, the simultaneous multi-colour imaging and the wide field of view of the instrument. In addition, it also has unique capability in the detection of faint near-Earth asteroids and will be used for the monitoring of short-duration transient and periodic sources, particularly those discovered by the intermediate Palomar Transient Factory (iPTF), and the upcoming Zwicky Transient Facility (ZTF)

    The role of the humoral immune response to Clostridium difficile toxins A and B in susceptibility to C. difficile infection: a case-control study

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    Antibody levels to Clostridium difficile toxin A (TcdA), but not toxin B (TcdB), have been found to determine risk of C. difficile infection (CDI). Historically, TcdA was thought to be the key virulence factor; however the importance of TcdB in disease is now established. We re-evaluated the role of antibodies to TcdA and TcdB in determining patient susceptibility to CDI in two separate patient cohorts. In contrast to earlier studies, we find that CDI patients have lower pre-existing IgA titres to TcdB, but not TcdA, when compared to control patients. Our findings suggest that mucosal immunity to TcdB may be important in the early stages of infection and identifies a possible target for preventing CDI progression

    Peer victimization in single-grade and multigrade classrooms

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    Although peer victimization mainly takes place within classrooms, little is known about the impact of the classroom context. To this end, we examined whether single-grade and multigrade classrooms (referring to classrooms with one and two grades in the same room) differ in victim-bully relationships in a sample of elementary school children (646 students; age 8-12 years; 50% boys). The occurrence of victim-bully relationships was similar in single-grade and multigrade classrooms formed for administrative reasons, but lower in multigrade classrooms formed for pedagogical reasons. Social network analyses did not provide evidence that peer victimization depended on age differences between children in any of the three classroom contexts. Moreover, in administrative multigrade classrooms, cross-grade victim-bully relationships were less likely than same-grade victim-bully relationships. The findings did not indicate that children in administrative multigrade classrooms are better or worse off in terms of victim-bully relationships than are children in single-grade classrooms
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