540 research outputs found

    On pointless diagonal Fermat curves

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    We give an improved asymptotic upper bound on the number of diagonal Fermat curves Axℓ+Byℓ=zℓAx^{\ell}+By^{\ell}=z^{\ell} over Fq\mathbb{F}_{q} with no Fq\mathbb{F}_{q}-rational points, where ℓ\ell is a prime number dividing q−1q-1.Comment: 10 page

    A retrospective study of cognitive function in doctors and dentists with suspected performance problems: an unsuspected but significant concern.

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    OBJECTIVE: To examine the performance assessments and cognitive function of practitioners referred to the National Clinical Assessment Service (NCAS). DESIGN: Retrospective observational study. SETTING: Practitioners referred to NCAS for performance assessment due to suspected performance problems. PARTICIPANTS: One hundred and nine practitioners over the age of 45 years referred to NCAS between 1 September 2008 and 30 June 2012. MAIN OUTCOME MEASURES: Reasons for referral of practitioners and their characteristics; details of their assessments including screening for cognition using Addenbrooke's Cognitive Examination Revised (ACE-R); outcome of the process. RESULTS: Reasons for referral included 'clinical difficulties' and 'governance or safety issues'. Eighty-seven practitioners scored above 88 on ACE-R. Twenty-two were found to have an ACE-R score of ≀88. On further assessment, 14 of these 22 practitioners were found to have cognitive impairment. The majority of all practitioners were found to be performing below the expected level of practice for someone at their grade and specialty. Of those scoring ≀88 on the screening, only seven continued in clinical practice. CONCLUSIONS: A high proportion of practitioners scoring poorly on ACE-R were found to have cognitive impairment following detailed neuropsychological testing, the youngest aged 46 years. Many were working in isolation. Nearly all practitioners scoring poorly on ACE-R were international medical graduates; reasons for this are unclear. Performance assessment results showed persisting failings in the practitioners' record keeping and in their assessment of patients. Our findings highlight the need for increased vigilance and training of responsible officers to recognise performance problems and emphasise the importance of comprehensive assessment

    Research In Outdoor Education: Group Development And Group Dynamics

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    This article contains the text of a keynote presentation at the Inaugural Symposium for Research in Outdoor Education at Bradford Woods, January 1992,. The presentation focused on the development of positive group dynamics

    Group Development and Group Dynamics in Outdoor Education

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    This paper presents an update of the research on group development and group dynamics in out­door education since the 1992 edition of these Proceedings. The research is presented within the six categories of individual and personal dimensions: group process and structure, group functions and tasks, leadership and power, environmental influences, and the impact of the group on the in­dividual. The paper includes a discussion of pertinent research in the fields of social work, com­munications, and management Specific recommendations are made for future research in outdoor education focusing on group development and dynamics

    Memory accumulation mechanisms in human cortex are independent of motor intentions

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    Previous studies on perceptual decision-making have often emphasized a tight link between decisions and motor intentions. Human decisions, however, also depend on memories or experiences that are not closely tied to specific motor responses. Recent neuroimaging findings have suggested that, during episodic retrieval, parietal activity reflects the accumulation of evidence for memory decisions. It is currently unknown, however, whether these evidence accumulation signals are functionally linked to signals for motor intentions coded in frontoparietal regions and whether activity in the putative memory accumulator tracks the amount of evidence for only previous experience, as reflected in "old" reports, or for both old and new decisions, as reflected in the accuracy of memory judgments. Here, human participants used saccadic-eye and hand-pointing movements to report recognition judgments on pictures defined by different degrees of evidence for old or new decisions. A set of cortical regions, including the middle intraparietal sulcus, showed a monotonic variation of the fMRI BOLD signal that scaled with perceived memory strength (older > newer), compatible with an asymmetrical memory accumulator. Another set, including the hippocampus and the angular gyrus, showed a nonmonotonic response profile tracking memory accuracy (higher > lower evidence), compatible with a symmetrical accumulator. In contrast, eye and hand effector-specific regions in frontoparietal cortex tracked motor intentions but were not modulated by the amount of evidence for the effector outcome. We conclude that item recognition decisions are supported by a combination of symmetrical and asymmetrical accumulation signals largely segregated from motor intentions

    Erosion and Accretion Trends of New Hampshire Beaches from December 2016 to March 2020: Results of the Volunteer Beach Profile Monitoring Program

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    New Hampshire Atlantic beaches were monitored from December 2016 to March 2020 to determine seasonal changes in morphology and elevation, assess the response of the beaches to storms with respect to erosion and subsequent recovery, and develop a baseline to determine long-term trends in beach size, elevation, and position. A unique aspect of this study was the involvement of community volunteers working together with the University of New Hampshire (UNH) Center for Coastal and Ocean Mapping, UNH Cooperative Extension, New Hampshire Sea Grant, and the New Hampshire Geological Survey. The monitoring network consisted of thirteen stations located at six of the major beaches, including each of the state beaches. Monitoring stations were located at Wallis Sands, Jenness Beach, North Hampton Beach, North Beach, Hampton Beach, and Seabrook Beach. At least two stations were located at each beach (Seabrook Beach had three stations). Beach elevation profiles were run routinely at each station at approximately three- to four-week intervals. Additional measurements were made following several major storms. In total, approximately 400 elevation profiles were run at the thirteen stations. The elevation profiles were run using the Emery (1961) method which utilizes two calibrated rods and the horizon for leveling. Sediment volume calculations were made for each profile that approximated the amount of material in the intertidal zone for that profile at that point in time for a one-meter wide swath of the beach. Seasonal changes and storm impacts on beach elevations, profile characteristics, and sediment volumes are discussed in detail for each beach and the major conditions and processes that control their stability discussed

    The association of cold weather and all-cause and cause-specific mortality in the island of Ireland between 1984 and 2007

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.This article has been made available through the Brunel Open Access Publishing Fund.Background This study aimed to assess the relationship between cold temperature and daily mortality in the Republic of Ireland (ROI) and Northern Ireland (NI), and to explore any differences in the population responses between the two jurisdictions. Methods A time-stratified case-crossover approach was used to examine this relationship in two adult national populations, between 1984 and 2007. Daily mortality risk was examined in association with exposure to daily maximum temperatures on the same day and up to 6 weeks preceding death, during the winter (December-February) and cold period (October-March), using distributed lag models. Model stratification by age and gender assessed for modification of the cold weather-mortality relationship. Results In the ROI, the impact of cold weather in winter persisted up to 35 days, with a cumulative mortality increase for all-causes of 6.4% (95%CI=4.8%-7.9%) in relation to every 1oC drop in daily maximum temperature, similar increases for cardiovascular disease (CVD) and stroke, and twice as much for respiratory causes. In NI, these associations were less pronounced for CVD causes, and overall extended up to 28 days. Effects of cold weather on mortality increased with age in both jurisdictions, and some suggestive gender differences were observed. Conclusions The study findings indicated strong cold weather-mortality associations in the island of Ireland; these effects were less persistent, and for CVD mortality, smaller in NI than in the ROI. Together with suggestive differences in associations by age and gender between the two Irish jurisdictions, the findings suggest potential contribution of underlying societal differences, and require further exploration. The evidence provided here will hope to contribute to the current efforts to modify fuel policy and reduce winter mortality in Ireland

    Public attitudes to inequality in water distribution: Insights from preferences for water reallocation from irrigators to Aboriginal Australians

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    Water allocation regimes that adjudicate between competing uses are in many countries under pressure to adapt to increasing demands, climate‐driven shortages, expectations for equity of access, as well as societal changes in values and priorities. International authorities expound standards for national allocation regimes that include robust processes for addressing the needs of ‘new entrants' and for varying existing entitlements within sustainable limits. The claims of Indigenous peoples to water represents a newly recognised set of rights and interests that will test the ability of allocation regimes to address the global water governance goal of equity. No study has sought to identify public attitudes or willingness to pay for a fairer allocation of water rights between Indigenous and non‐Indigenous people. We surveyed households from the jurisdictions of Australia's Murray‐Darling Basin, a region undergoing a historic government‐led recovery of water, and found that 69.2% of respondents support the principle of reallocating a small amount of water from irrigators to Aboriginal people via the water market. Using contingent valuation, we estimated households are willing to pay A21.78inaone‐offlevy.Theaggregatevaluecalculatedforhouseholdsinthebasinâ€ČsjurisdictionswasA21.78 in a one‐off levy. The aggregate value calculated for households in the basin's jurisdictions was A74.5 million, which is almost double a recent government commitment to fund the acquisition of entitlements for Aboriginal nations of this basin. Results varied by state of residency and affinity with environmental groups. An information treatment that presented narrative accounts from Aboriginal people influenced the results. Insights from this study can inform water reallocation processes

    Brain aerobic glycolysis and resilience in Alzheimer disease

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    The distribution of brain aerobic glycolysis (AG) in normal young adults correlates spatially with amyloid-beta (AÎČ) deposition in individuals with symptomatic and preclinical Alzheimer disease (AD). Brain AG decreases with age, but the functional significance of this decrease with regard to the development of AD symptomatology is poorly understood. Using PET measurements of regional blood flow, oxygen consumption, and glucose utilization-from which we derive AG-we find that cognitive impairment is strongly associated with loss of the typical youthful pattern of AG. In contrast, amyloid positivity without cognitive impairment was associated with preservation of youthful brain AG, which was even higher than that seen in cognitively unimpaired, amyloid negative adults. Similar findings were not seen for blood flow nor oxygen consumption. Finally, in cognitively unimpaired adults, white matter hyperintensity burden was found to be specifically associated with decreased youthful brain AG. Our results suggest that AG may have a role in the resilience and/or response to early stages of amyloid pathology and that age-related white matter disease may impair this process
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