87 research outputs found

    "Barchan" dunes in the lab

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    We demonstrate the feasibility of studying dunes in a laboratory experiment. It is shown that an initial sand pile, under a wind flow carrying sand, flattens and gets a shape recalling barchan dunes. An evolution law is proposed for the profile and the summit of the dune. The dune dynamics is shown to be shape invariant. The invariant shape, the ``dune function'' is isolated.Comment: 3 pages, 4 figure

    Generation of magnetic field by dynamo action in a turbulent flow of liquid sodium

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    We report the observation of dynamo action in the VKS experiment, i.e., the generation of magnetic field by a strongly turbulent swirling flow of liquid sodium. Both mean and fluctuating parts of the field are studied. The dynamo threshold corresponds to a magnetic Reynolds number Rm \sim 30. A mean magnetic field of order 40 G is observed 30% above threshold at the flow lateral boundary. The rms fluctuations are larger than the corresponding mean value for two of the components. The scaling of the mean square magnetic field is compared to a prediction previously made for high Reynolds number flows.Comment: 4 pages, 5 figure

    Labelled Tableaux For Non-Normal Modal Logics

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    In this paper we show how to extend KEM, a tableaux-like proof system for normal modal logic, in order to deal with classes of non-normal modal logic, such as monotonic and regular, in a uniform and modular way

    Automated Synthesis of Tableau Calculi

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    This paper presents a method for synthesising sound and complete tableau calculi. Given a specification of the formal semantics of a logic, the method generates a set of tableau inference rules that can then be used to reason within the logic. The method guarantees that the generated rules form a calculus which is sound and constructively complete. If the logic can be shown to admit finite filtration with respect to a well-defined first-order semantics then adding a general blocking mechanism provides a terminating tableau calculus. The process of generating tableau rules can be completely automated and produces, together with the blocking mechanism, an automated procedure for generating tableau decision procedures. For illustration we show the workability of the approach for a description logic with transitive roles and propositional intuitionistic logic.Comment: 32 page

    Prevalence and factors associated with alcohol and drug-related disorders in prison: a French national study

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    BACKGROUND: Most studies measuring substance-use disorders in prisons focus on incoming or on remand prisoners and are generally restricted to drugs. However, there is evidence that substance use initiation or continuation occurs in prison, and that alcohol use is common. The aim of this study is 1) to assess prevalence of both drug and alcohol abuse and dependence (DAD/AAD) in a national randomised cohort of French prisoners, short or long-term sentence 2) to assess the risk factors associated with DAD/AAD in prison. a stratified random strategy was used to select 1) 23 prisons among the different types of prison 2) 998 prisoners. Diagnoses were assessed according to a standardized procedure, each prisoner being assessed by two psychiatrists, one junior, using a structured interview (MINI 5 plus), and one senior, completing the procedure with an open clinical interview. At the end of the interview the clinicians met and agreed on a list of diagnoses. Cloninger's Temperament and Character Inventory (TCI) was also used. RESULTS: More than a third of prisoners presented either AAD or DAD in the last 12 months. Cannabis was the most frequent drug and just under a fifth of prisoners had AAD. AAD and DAD were clearly different for the following: socio-demographic variables, childhood history, imprisonment characteristics, psychiatric comorbidity and Cloninger's TCI. Profiles of AAD in prison are similar to type II alcoholism. CONCLUSION: Regular screening of AAD/DAD in prison, and specific treatment programmes taking into account differences between prisoners with an AAD and prisoners with a DAD should be a public health priority in priso

    250 labels used to stigmatise people with mental illness

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    <p>Abstract</p> <p>Background</p> <p>The stigma against people with mental illness is a major barrier to help-seeking in young people for mental health problems. The objective of this study was to investigate the extent of stigma in relation to treatment avoidance in 14 year-old school students in England in relation to how they refer to people with mental illness.</p> <p>Methods</p> <p>This is a qualitative, cross-sectional study. The data were gathered as part of the baseline assessment for an intervention study intended to reduce stigma among 14 year old school students. The participating schools were two grammar (selective) schools and three comprehensive (non-selective) schools. At the start of the lesson, the students were asked 'What sorts of words or phrases might you use to describe someone who experiences mental health problems?' Words and terms used to refer to mental illness were enumerated. Using the grounded theory approach, words and terms were grouped in terms of their denotative and connotative meanings. Labels were then derived to capture the key themes attached by the students to the concepts of mental illness. The frequencies of occurrence for each word were also tabulated.</p> <p>Results</p> <p>400 of the 472 participating students (85%) provided 250 words and terms to describe a person with mental illness. Five themes were identified from the data. The first theme called 'popular derogatory terms' (116 items) accounted for nearly half of the words examined. The second theme occurred less often and was described as 'negative emotional state' (61 items). The third theme demonstrated the confusion of young people between physical disabilities, learning difficulties and mental health problems (38 items). The use of psychiatric diagnoses (15 items) and terms related to violence (9 items) were unexpectedly uncommon.</p> <p>Conclusion</p> <p>Our findings suggest the hypothesis that help-seeking by mentally ill young people may be improved by interventions that address both their lack of factual information about mental illness, and those which reduce their strong negative emotional reactions towards people with mental illness.</p

    It takes patience and persistence to get negative feedback about patients’ experiences: a secondary analysis of national inpatient survey data

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    Background: Patient experience surveys are increasingly used to gain information about the quality of healthcare. This paper investigates whether patients who respond before and after reminders to a large national survey of inpatient experience differ in systematic ways in how they evaluate the care they received. Methods: The English national inpatient survey of 2009 obtained data from just under 70,000 patients. We used ordinal logistic regression to analyse their evaluations of the quality of their care in relation to whether or not they had received a reminder before they responded. Results: 33% of patients responded after the first questionnaire, a further 9% after the first reminder, and a further 10% after the second reminder. Evaluations were less positive among people who responded only after a reminder and lower still among those who needed a second reminder. Conclusions: Quality improvement efforts depend on having accurate data and negative evaluations of care received in healthcare settings are particularly valuable. This study shows that there is a relationship between the time taken to respond and patients’ evaluations of the care they received, with early responders being more likely to give positive evaluations. This suggests that bias towards positive evaluations could be introduced if the time allowed for patients to respond is truncated or if reminders are omitted

    La politique agricole commune et les Ă©changes

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    The lowering of tariff-walls, first between the « Six », then between the « Nine », has permitted intensification of . intra-EC trade. But towards the rest of the world, the Community always appears as a consuming area, because apart from - limited and fluctuating surplues, important deficits continue to exist. In consideration of this, a new enlargement, even if it may create a new intra-EC dynamic, will probably only have a weak effect on aggregate food self-sufficiency.L'abaissement des barrières douanières, d'abord entre les « Six », ensuite entre les « Neuf », a permis l'intensification des échanges intra-communautaires. Mais, vis-à-vis du reste du monde, la Communauté apparaît toujours comme, une zone de consommation car à côté d'excédents limités et fluctuants subsistent de profonds déficits. A cet égard un nouvel élargissement, même s'il est susceptible de créer une nouvelle dynamique intra-communautaire, n'aura sans doute qu'un faible effet sur le taux de couverture agro-alimentaire global.Gasquet O. de. La politique agricole commune et les échanges. In: Économie rurale. N°142, 1981. p. 37

    Les investissements dans l'agriculture française

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    [fre] Au niveau de l'ensemble de la branche agricole, les investissements ont augmenté de 1959 à 1974 et stagné depuis. Certaines évolutions sont masquées par des situations de trésorerie conjoncturelles mais il apparaît des changements assez profonds dans la nature et la quantité des investissements en matériel et bâtiments. Les améliorations foncières sont mal connues. Au niveau des départements on dispose de quelques données pour 1979. Une première analyse permet de penser que les investissements accroissent les disparités entre départements. [eng] For agriculture as a whole, investments increased from 1959 to 1974 and stagnated since then. Though short term changes in farmer's cash flows may confuse the analysis some rather deep changes in the amounts and nature of investments in machinery and buildings appear. Data on land improvements are poor. For the "départements", some preliminary data for 1979 exist. It appears that investments may increase income disparities between "départements".

    Evolution du débouché communautaire

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    de Gasquet O. Evolution du débouché communautaire. In: Économie rurale. N°155, 1983. p. 46
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