125 research outputs found

    Thermal Tides in Fluid Extrasolar Planets

    Full text link
    Asynchronous rotation and orbital eccentricity lead to time-dependent irradiation of the close-in gas giant exoplanets -- the hot Jupiters. This time-dependent surface heating gives rise to fluid motions which propagate throughout the planet. We investigate the ability of this "thermal tide" to produce a quadrupole moment which can couple to the stellar gravitational tidal force. While previous investigations discussed planets with solid surfaces, here we focus on entirely fluid planets in order to understand gas giants with small cores. The Coriolis force, thermal diffusion and self-gravity of the perturbations are ignored for simplicity. First, we examine the response to thermal forcing through analytic solutions of the fluid equations which treat the forcing frequency as a small parameter. In the "equilibrium tide" limit of zero frequency, fluid motion is present but does not induce a quadrupole moment. In the next approximation, finite frequency corrections to the equilibrium tide do lead to a nonzero quadrupole moment, the sign of which torques the planet {\it away} from synchronous spin. We then numerically solve the boundary value problem for the thermally forced, linear response of a planet with neutrally stratified interior and stably stratified envelope. The numerical results find quadrupole moments in agreement with the analytic non-resonant result at sufficiently long forcing period. Surprisingly, in the range of forcing periods of 1-30 days, the induced quadrupole moments can be far larger than the analytic result due to response of internal gravity waves which propagate in the radiative envelope. We discuss the relevance of our results for the spin, eccentricity and thermal evolution of hot Jupiters.Comment: 12 pages, 7 figures, submitted to Ap

    Stop with the FLO: using text messaging to improve retention rates in University Students

    Get PDF
    Student attrition rates in undergraduate programmes are unacceptably high. The study undertaken evaluated the use of ‘FLO’, a mobile phone automated text messaging service, designed to provide information, support and reassurance in order to help alleviate the stress and anxieties that some new undergraduate students experience during the early phase of their studies. The objectives of the study were to evaluate how use of automated mobile phone texts using a system known as FLO could usefully supplement the pastoral support currently offered to new undergraduate students. A qualitative and quantitative evaluation was conducted using an open-ended questionnaire designed specifically for the study.The sample were 39 first year, undergraduate, Level 4 students from Social Welfare Law (n=16) and Sport and Exercise (n=23) who signed up to receive texts from FLO. The questionnaire was administered in a classroom situation one week after use of FLO had ceased. Data were analysed through use of a descriptive statistics and thematic analysis. Thirty nine students signed up to receive texts from FLO and 25 (64%) completed the Qualtrics questionnaire. Largely positive findings predominated including that text messages increased a sense of belonging to the University and helped students to stay on the course. It is concluded that FLO or use of similar mobile phone protocols may be a useful addition to approaches to improve undergraduate student retention rates

    Field measurement and subjects' votes assessment on thermal comfort in high-rise hostels in Malaysia

    Get PDF
    The need to design for low energy consumption dwellings has induced Malaysian architects to design naturally ventilated high-rise hostels (HH), near the capital, Kuala Lumpur. Objective and subjective measurements for thermal comfort investigations were conducted in two high-rise university hostels located in Universiti Malaya, Petaling Jaya (HH1) and Universiti Putra Malaysia, Serdang (HH2) from May 12 to June 19 in 2007. Eighteen rooms located at first, fifth, and top floor of each HH were measured for different orientations. The measured rooms were naturally ventilated with ceiling fans. Thermal comfort variables were measured prior to the subjective measurement. A total of 208 student occupants responded to the questionnaire. Subjects with 6 months and over living experience in those HH were selected randomly. This study was aimed: (1) to assess the indoor microclimate of each naturally ventilated HH, (2) to identify student occupants' thermal sensation during rainy and clear day, and (3) to simulate the neutral operating temperature for rooms in naturally ventilated high-rise hostels. Findings revealed that room in HH1 which is located on high land and shaded has a more constant operating temperature distribution than rooms in HH2 that is located on lower land and un-shaded. Operating temperature ranges for HH1 and HH2 were 27—31°C and 26—41°C, respectively. Results suggested that there is also a possibility that thermal comfort is achievable in shaded naturally ventilated hostels with a window-to-wall ratio of 0.35 where the internal—external relative humidity is above 70% RH, especially in south-facing rooms

    Distributed transactional reads: the strong, the quick, the fresh & the impossible

    Get PDF
    International audienceThis paper studies the costs and trade-offs of providing transactional consistent reads in a distributed storage system. We identify the following dimensions: read consistency, read delay (latency), and data freshness. We show that there is a three-way trade-off between them, which can be summarised as follows: (i) it is not possible to ensure at the same time order-preserving (e.g., causally-consistent) or atomic reads, Minimal Delay, and maximal freshness; thus, reading data that is the most fresh without delay is possible only in a weakly-isolated mode; (ii) to ensure atomic or order-preserving reads at Minimal Delay imposes to read data from the past (not fresh); (iii) however, order-preserving minimal-delay reads can be fresher than atomic; (iv) reading atomic or order-preserving data at maximal freshness may block reads or writes indefinitely. Our impossibility results hold independently of other features of the database, such as update semantics (totally ordered or not) or data model (structured or unstructured). Guided by these results, we modify an existing protocol to ensure minimal-delay reads (at the cost of freshness) under atomic-visibility and causally-consistent semantics. Our experimental evaluation supports the theoretical results

    Archeological Investigations at the Santa Maria Creek Site (41CW104) Caldwell County, Texas

    Get PDF
    The excavations by Atkins at the Santa Maria Creek site (41CW104) described in the following report have succeeded in bringing together a myriad of information regarding aboriginal occupations in eastern Central Texas at the dawn of the Historic period. The analysis of the materials recovered from National Register of Historic Places testing and data recovery has demonstrated that even a site buried in sandy, bioturbated sediments can still significantly add to the archeological record. This becomes even more important for areas such as Caldwell County, Texas, which have witnessed few such investigations. The report utilized a wide array of analytical techniques to unravel the site, including extensive ethnohistorical research, artifact analysis, special studies, and experimental archeology

    The Lantern Vol. 69, No. 2, Spring 2002

    Get PDF
    • What was Said in the Court of Riong • Bailan Pies (Dancing Feet) • Canard • Vernacular City • Saturday Night Motorcycles • The Muse • I Stuffed my Face in the Herbs • Jacob\u27s Nightingale • At Tracey\u27s • Ona Time, a Rhym-mer • For Yo Yo Ma\u27s Encore • Two Minutes from Earl\u27s Court Tube Station • For Two • Bald • This Year\u27s Love • The Dimmer Switch • Tickertape • Imaginary Highway • First Kiss and Related Terrors • Hairball • His Hobbies • Spaghetti Dinnerhttps://digitalcommons.ursinus.edu/lantern/1160/thumbnail.jp

    Study protocol for a randomised placebo-controlled trial of pramipexole in addition to mood stabilisers for patients with treatment resistant bipolar depression (the PAX-BD study)

    Get PDF
    Abstract Background Treatment Resistant Bipolar Depression (TRBD) is a major contributor to the burden of disease associated with Bipolar Disorder (BD). Treatment options for people experiencing bipolar depression are limited to three interventions listed by National Institute for Health and Care: lamotrigine, quetiapine and olanzapine, of which the latter two are often not well tolerated. The majority of depressed people with BD are therefore prescribed antidepressants despite limited efficacy. This demonstrates an unmet need for additional interventions. Pramipexole has been shown to improve mood symptoms in animal models of depression, in people with Parkinson’s Disease and two proof of principle trials of pramipexole for people with BD who are currently depressed. Methods The PAX-BD study, funded by the United Kingdom (UK) National Institute for Health Research, aims to extend previous findings by assessing the efficacy, safety and health economic impact of pramipexole in addition to mood stabilisers for patients with TRBD. A randomised, double-blind, placebo controlled design is conducted in a naturalistic UK National Health Service setting. An internal pilot study to examine feasibility and acceptability of the study design is included. Participants with TRBD are screened from National Health Service secondary care services in up to 40 mental health trusts in the UK, with the aim of recruiting approximately 414 participants into a pre-randomisation phase to achieve a target of 290 randomised participants. Primary safety and efficacy measures are at 12 weeks following randomisation, with follow up of participants to 52 weeks. The primary outcome is depressive symptoms as measured by Quick Inventory for Depressive Symptomatology – Self Report. Secondary outcomes include changes in anxiety, manic symptoms, tolerability, acceptability, quality of life and cost-effectiveness. Outcome measures are collected remotely using self-report tools implemented online, and observer-rated assessments conducted via telephone. ANCOVA will be used to examine the difference in rating scale scores between treatment arms, and dependent on compliance in completion of weekly self-report measures. A mixed effects linear regression model may also be used to account for repeated measures. Trial registration ISRCTN72151939. Registered on 28 August 2019, http://www.isrctn.com/ISRCTN72151939 Protocol Version: 04-FEB-2021, Version 9.0

    Archeological Investigations at the Santa Maria Creek Site (41CW104) Caldwell County, Texas

    Get PDF
    Report on the excavations at the Santa Maria creek site in Caldwell County, Texas during 2006 and 2007. The report includes a discussion of research methods, analysis of the findings, and history of the area

    Quality assurance in pathology in colorectal cancer screening and diagnosis—European recommendations

    Get PDF
    In Europe, colorectal cancer is the most common newly diagnosed cancer and the second most common cause of cancer deaths, accounting for approximately 436,000 incident cases and 212,000 deaths in 2008. The potential of high-quality screening to improve control of the disease has been recognized by the Council of the European Union who issued a recommendation on cancer screening in 2003. Multidisciplinary, evidence-based European Guidelines for quality assurance in colorectal cancer screening and diagnosis have recently been developed by experts in a pan-European project coordinated by the International Agency for Research on Cancer. The full guideline document consists of ten chapters and an extensive evidence base. The content of the chapter dealing with pathology in colorectal cancer screening and diagnosis is presented here in order to promote international discussion and collaboration leading to improvements in colorectal cancer screening and diagnosis by making the principles and standards recommended in the new EU Guidelines known to a wider scientific community
    • …
    corecore