3,587 research outputs found

    Predicting the response of a submillimeter bolometer to cosmic rays

    Get PDF
    Bolometers designed to detect. submillimeter radiation also respond to cosmic, gamma, and x rays. Because detectors cannot be fully shielded from such energy sources, it is necessary to understand the effect of a photon or cosmic-ray particle being absorbed. The resulting signal (known as a glitch) can then be removed from raw data. We present measurements using an Americium-241 gamma radiation source to irradiate a prototype bolometer for the High Frequency Instrument in the Planck Surveyor satellite. Our measurements showed no variation in response depending on where the radiation was absorbed, demonstrating that the bolometer absorber and thermistor thermalize quickly. The bolometer has previously been fully characterized both electrically and optically. We find that using optically measured time constants underestimates the time taken for the detector to recover from a radiation absorption event. However, a full thermal model for the bolometer, with parameters taken from electrical and optical measurements, provides accurate time constants. Slight deviations from the model were seen at high energies; these can be accounted for by use of an extended model

    From Rat to Human: Regulation of Renin-Angiotensin System Genes by Sry

    Get PDF
    The testis determining protein, Sry, has functions outside of testis determination. Multiple Sry loci are found on the Y-chromosome. Proteins from these loci have differential activity on promoters of renin-angiotensin system genes, possibly contributing to elevation of blood pressure. Variation at amino acid 76 accounts for the majority of differential effects by rat proteins Sry1 and Sry3. Human SRY regulated rat promoters in the same manner as rat Sry, elevating Agt, Ren, and Ace promoter activity while downregulating Ace 2. Human SRY significantly regulated human promoters of AGT, REN, ACE2, AT2, and MAS compared to control levels, elevating AGT and REN promoter activity while decreasing ACE2, AT2, and MAS. While the effect of human SRY on individual genes is often modest, we show that many different genes participating in the renin-angiotensin system can be affected by SRY, apparently in coordinated fashion, to produce more Ang II and less Ang-(1–7)

    Analysis of Sry Duplications On the Rattus Norvegicus Y-Chromosome

    Get PDF
    Background: Gene copy number variation plays a large role in the evolution of genomes. In Rattus norvegicus and other rodent species, the Y-chromosome has accumulated multiple copies of Sry loci. These copy number variations have been previously linked with changes in phenotype of animal models such as the spontaneously hypertensive rat (SHR). This study characterizes the Y-chromosome in the Sry region of Rattus norvegicus, while addressing functional variations seen in the Sry protein products. Results: Eleven Sry loci have been identified in the SHR with one (nonHMG Sry) containing a frame shift mutation. The nonHMGSry is found and conserved in the related WKY and SD rat strains. Three new, previously unidentified, Sry loci were identified in this study (Sry3BII, Sry4 and Sry4A) in both SHR and WKY. Repetitive element analysis revealed numerous LINE-L1 elements at regions where conservation is lost among the Sry copies. In addition we have identified a retrotransposed copy of Med14 originating from spliced mRNA, two autosomal genes (Ccdc110 and HMGB1) and a normal mammalian Y-chromosome gene (Zfy) in the Sry region of the rat Y-chromosome. Translation of the sequences of each Sry gene reveals eight proteins with amino acid differences leading to changes in nuclear localization and promoter activation of a Sry-responsive gene. Sry-beta (coded by the Sry2 locus) has an increased cytoplasmic fraction due to alterations at amino acid 21. Sry gamma has altered gene regulation of the Sry1 promoter due to changes at amino acid 76. Conclusions: The duplication of Sry on the Rattus norvegicus Y-chromosome has led to proteins with altered functional ability that may have been selected for functions in addition to testis determination. Additionally, several other genes not normally found on the Y-chromosome have duplicated new copies into the region around the Sry genes. These suggest a role of active transposable elements in the evolution of the mammalian Y-chromosome in species such as Rattus norvegicus

    Internet-Based Vestibular Rehabilitation for Older Adults With Chronic Dizziness: A Randomized Controlled Trial in Primary Care

    Get PDF
    Purpose: Vestibular Rehabilitation (VR) is an effective intervention for dizziness due to vestibular dysfunction, but is seldom provided. We aimed to determine the effectiveness of internet-based VR for older adults experiencing dizziness in primary care. Methods: A single centre, single blind randomised controlled trial comparing an internet-based VR intervention with usual primary care was conducted with patients from 54 primary care practices in southern England (ISRCTN: 86912968). Patients aged 50 years and over with current dizziness exacerbated by head movements were included in the trial. Patients accessed an automated internet-based intervention that taught VR exercises and suggested cognitive behavioural management strategies. Dizziness was measured by the Vertigo Symptom Scale Short-Form (VSS-SF) at baseline, 3 and 6 months. The primary outcome was VSS-SF score at 6 months. Results: A total of 296 patients were randomized into the trial (66% female, median age 67). The VSS-SF was completed by 250 participants at 3 months (84%: 123 intervention (77%), 127 usual care (93%)) and 230 participants at 6 months (78%: 112 intervention (70%), 118 usual care (87%)). At 3 and 6 months dizziness symptoms were significantly lower in the internet-based VR group compared to usual care (2.75, 95% CI, 1.39 to 4.12; p<0.001 and 2.26, 95% CI, 0.39 to 4.12; p=0.018 respectively). Dizziness-related disability was also significantly lower in the internet-based VR condition, at 3 (6.15 95% CI, 2.81 to 9.49; p<0.001) and 6 month (5.58, 95% CI, 1.19 to 10.0; p=0.013). Conclusions: Internet-based VR improves dizziness and reduces dizziness-based disability in older primary care patients without requiring clinical support, and has potential for wide application in community settings

    High COVID-19 transmission potential associated with re-opening universities can be mitigated with layered interventions

    Get PDF
    Reopening of universities to students following COVID-19 restrictions risks increased transmission due to high numbers of social contacts and the potential for asymptomatic transmission. Here, the authors use a mathematical model with social contact data to estimate the impacts of reopening a typical non-campus based university in the UK

    Technology, time and transition in higher education : two different realities of everyday Facebook use in the first year of university in the UK.

    Get PDF
    Within the range of websites and apps that are part of first-year undergraduates’ digital environments, the social network site Facebook is perhaps the most popular and prominent. As such, the ubiquitous nature of Facebook in the higher education landscape has drawn much attention from scholars. Drawing on data from a longitudinal connective ethnography, this paper uses two ethnographic stories to explore further the realities of social media usage by newly enrolled undergraduate students in a UK university. These ethnographic stories tell two differing tales - one of connection, intent, use and organisation - the other, of disconnection, disengagement and unrealised expectations. Facebook structures students’ time at university both through connection and disconnection practices and examples of these are presented under two headings ‘I’m always on it’ and ‘Being academic’. First-year student experiences of Higher Education and social media use are not uniform, but nuanced and responsive to their specific ecosocial systems

    CHARIS Science: Performance Simulations for the Subaru Telescope's Third-Generation of Exoplanet Imaging Instrumentation

    Full text link
    We describe the expected scientific capabilities of CHARIS, a high-contrast integral-field spectrograph (IFS) currently under construction for the Subaru telescope. CHARIS is part of a new generation of instruments, enabled by extreme adaptive optics (AO) systems (including SCExAO at Subaru), that promise greatly improved contrasts at small angular separation thanks to their ability to use spectral information to distinguish planets from quasistatic speckles in the stellar point-spread function (PSF). CHARIS is similar in concept to GPI and SPHERE, on Gemini South and the Very Large Telescope, respectively, but will be unique in its ability to simultaneously cover the entire near-infrared JJ, HH, and KK bands with a low-resolution mode. This extraordinarily broad wavelength coverage will enable spectral differential imaging down to angular separations of a few λ/D\lambda/D, corresponding to \sim0.\!\!''1. SCExAO will also offer contrast approaching 10510^{-5} at similar separations, \sim0.\!\!''1--0.\!\!''2. The discovery yield of a CHARIS survey will depend on the exoplanet distribution function at around 10 AU. If the distribution of planets discovered by radial velocity surveys extends unchanged to \sim20 AU, observations of \sim200 mostly young, nearby stars targeted by existing high-contrast instruments might find \sim1--3 planets. Carefully optimizing the target sample could improve this yield by a factor of a few, while an upturn in frequency at a few AU could also increase the number of detections. CHARIS, with a higher spectral resolution mode of R75R \sim 75, will also be among the best instruments to characterize planets and brown dwarfs like HR 8799 cde and κ\kappa And b.Comment: 13 pages, 7 figures, proceedings from SPIE Montrea

    Study design of real world evidence for treatment of hyperkalemia in the emergency department (REVEAL-ED): A multicenter, prospective, observational study

    Get PDF
    OBJECTIVE: Hyperkalemia affects up to 10% of hospitalized patients and, if left untreated, can lead to serious cardiac arrhythmias or death. Although hyperkalemia is frequently encountered in the emergency department (ED), and is potentially life-threatening, standard of care for the treatment is poorly defined, with little supporting evidence. The main objectives of this observational study are to define the overall burden of hyperkalemia in the ED setting, describe its causes, the variability in treatment patterns and characterize the effectiveness and safety of ED standard of care therapies used in the United States. METHODS: This is an observational study evaluating the management of hyperkalemia in the ED. Two hundred and three patients who presented to the ED with a potassium value ≥5.5 mmol/L were enrolled in the study at 14 sites across the United States. Patients were treated per standard of care practices at the discretion of the patient\u27s physician. In patients who received a treatment for hyperkalemia, blood samples were drawn at pre-specified time points and serum potassium values were recorded. The change in potassium over 4 hours and the adverse events after standard of care treatment were analyzed. RESULTS AND CONCLUSION: This article describes the background, rationale, study design, and methodology of the REVEAL-ED (Real World Evidence for Treatment of Hyperkalemia in the Emergency Department) trial, a multicenter, prospective, observational study evaluating contemporary management of patients admitted to the ED with hyperkalemia

    Contacts and behaviours of university students during the COVID-19 pandemic at the start of the 2020/2021 academic year

    Get PDF
    University students have unique living, learning and social arrangements which may have implications for infectious disease transmission. To address this data gap, we created CONQUEST (COroNavirus QUESTionnaire), a longitudinal online survey of contacts, behaviour, and COVID-19 symptoms for University of Bristol (UoB) staff/students. Here, we analyse results from 740 students providing 1261 unique records from the start of the 2020/2021 academic year (14/09/2020–01/11/2020), where COVID-19 outbreaks led to the self-isolation of all students in some halls of residences. Although most students reported lower daily contacts than in pre-COVID-19 studies, there was heterogeneity, with some reporting many (median = 2, mean = 6.1, standard deviation = 15.0; 8% had ≥ 20 contacts). Around 40% of students’ contacts were with individuals external to the university, indicating potential for transmission to non-students/staff. Only 61% of those reporting cardinal symptoms in the past week self-isolated, although 99% with a positive COVID-19 test during the 2 weeks before survey completion had self-isolated within the last week. Some students who self-isolated had many contacts (mean = 4.3, standard deviation = 10.6). Our results provide context to the COVID-19 outbreaks seen in universities and are available for modelling future outbreaks and informing policy
    corecore