1,330 research outputs found

    Beryllium fastener technology

    Get PDF
    Program was conducted to develop, produce, and test optimum-configuration, beryllium prestressed and blind fasteners. The program was carried out in four phases - phase 1, feasibility study, phase 2, development, phase 3, evaluation of beryllium alloys, and phase 4, fabrication and testing

    Extending the theory of Owicki and Gries with a logic of progress

    Get PDF
    This paper describes a logic of progress for concurrent programs. The logic is based on that of UNITY, molded to fit a sequential programming model. Integration of the two is achieved by using auxiliary variables in a systematic way that incorporates program counters into the program text. The rules for progress in UNITY are then modified to suit this new system. This modification is however subtle enough to allow the theory of Owicki and Gries to be used without change

    Using domain-independent problems for introducing formal methods

    Get PDF
    The key to the integration of formal methods into engineering practice is education. In teaching, domain-independent problems i.e., not requiring prior engineering background-offer many advantages. Such problems are widely available, but this paper adds two dimensions that are lacking in typical solutions yet are crucial to formal methods: (i) the translation of informal statements into formal expressions; (ii) the role of formal calculation (including proofs) in exposing risks or misunderstandings and in discovering pathways to solutions. A few example problems illustrate this: (a) a small logical one showing the importance of fully capturing informal statements; (b) a combinatorial one showing how, in going from "real-world" formulations to mathematical ones, formal methods can cover more aspects than classical mathematics, and a half-page formal program semantics suitable for beginners is presented as a support; (c) a larger one showing how a single problem can contain enough elements to serve as a Leitmotiv for all notational and reasoning issues in a complete introductory course. An important final observation is that, in teaching formal methods, no approach can be a substitute for an open mind, as extreme mathphobia appears resistant to any motivation

    Invasive Techniken in der Notfallmedizin: IV. Koniotomie im Notarztdienst

    Get PDF
    Zusammenfassung: Die Koniotomie im Notarztdienst ist eine sehr invasive Methode zur Atemwegssicherung. Sie ist aber unabdingbar, wenn andere weniger invasive Verfahren der Atemwegssicherung misslingen oder sich situationsabhängig als nicht zweckmäßig erweisen. Für die Durchführung wurden verschiedene Verfahren beschrieben, die in anatomisch-chirurgische Präpariertechniken und Punktionsverfahren unterteilt werden können. Das im jeweiligen Notarztsystem bevorzugte Verfahren orientiert sich meist an abteilungsüblichen Standards, die vom klinischen Vorgehen abgeleitet werden. Ausbildungs- und Trainingsmöglichkeiten für die einzelnen Verfahren bestehen in der Intensivmedizin, am Leichenpräparat und am Phantom. In dieser Arbeit werden verschiedene Methoden der Koniotomie besprochen sowie eine anatomische Präpariertechnik und 2Punktionsverfahren im Detail dargestell

    Suspension-adapted Chinese hamster ovary-derived cells expressing green fluorescent protein as a screening tool for biomaterials

    Get PDF
    Synthetic biomaterials play an important role in regenerative medicine. To be effective they must support cell attachment and proliferation in addition to being non-toxic and non-immunogenic. We used a suspension-adapted Chinese hamster ovary-derived cell line expressing green fluorescent protein (GFP) to assess cell attachment and growth on synthetic biomaterials by direct measurement of GFP-specific fluorescence. To simplify operations, all cell cultivation steps were performed in orbitally-shaken, disposable containers. Comparative studies between this GFP assay and previously established cell quantification assays demonstrated that this novel approach is suitable for rapid screening of a large number of samples. Furthermore the utility of our assay system was confirmed by evaluation of cell growth on three polyvinylidene fluoride polymer scaffolds that differed in pore diameter and drawing conditions. The data presented here prove the general utility of GFP-expressing cell lines and orbital shaking technology for the screening of biomaterials for tissue engineering application

    Relationship of glycaemic control and hypoglycaemic episodes to 4-year cardiovascular outcomes in people with type 2 diabetes starting insulin

    Get PDF
    AIMS: To examine the relationships between glycated haemoglobin (HbA1c) and cardiovascular (CV) events in people beginning insulin in routine clinical practice in Europe, North America and Asia in a non-interventional study, the Cardiovascular Risk Evaluation in people with Type 2 Diabetes on Insulin Therapy (CREDIT) study. METHODS: Data on 2999 people were collected prospectively over 4 years from physician reports. The primary outcome was the composite of stroke or myocardial infarction (MI) or CV-specific death. Events were blindly adjudicated. The relative hazards of CV events were described from Cox proportional hazards models incorporating patient risk factors, with updated average HbA1c as a time-dependent covariate. The relationship of severe and symptomatic hypoglycaemia (collected during the 6 months before yearly ascertainment) with CV and all-cause mortality was examined. RESULTS: A total of 147 primary events were accrued during up to 54 months of follow-up. In all, 60 CV-specific deaths, 44 non-fatal MIs and 57 non-fatal strokes occurred, totalling 161 events. There was a significant positive relationship between updated mean HbA1c and primary outcome: hazard ratio (HR) 1.25 [95% confidence interval (CI) 1.12-1.40; p < 0.0001]. CV death [HR 1.31 (95% CI 1.10-1.57); p = 0.0027] and stroke [HR 1.36 (95% CI 1.17-1.59); p < 0.0001] were both strongly associated with HbA1c, while MI was not [HR 1.05 (95% CI 0.83-1.32)]. One or more severe hypoglycaemic episodes affected 175 participants, while 1508 participants experienced one or more symptomatic hypoglycaemic events. We found no relationship between severe/symptomatic hypoglycaemic events and CV-specific/all-cause death. CONCLUSIONS: Ongoing poorer glucose control was associated with CV events; hypoglycaemia was not associated with CV-specific/all-cause death

    Климатические особенности и статистические оценки изменения элементов климата в районах вечной мерзлоты на территории севера Западной Сибири

    Get PDF
    Актуальность работы связана с необходимостью оценки изменений климата, влияющих на многолетнюю мерзлоту, в связи с возможным увеличением выбросов парниковых газов и увеличения аварийности на объектах промышленной, в том числе и нефтегазовой, инфраструктуры при таянии многолетнемерзлых пород. Цель работы: исследование современных изменений характеристик климата, непосредственно влияющих на термическое состояние почвогрунтов в районах распространения многолетней мерзлоты севера Западной Сибири. Методы исследования. Анализ многолетних изменений метеорологических данных включал в себя проверку нулевых гипотез о случайности и однородности рядов наблюдений и наличия тренда. Проверка на однородность осуществлялась с помощью теста Аббе, на случайность - критерием Питмена, на наличие тренда производилась с помощью критерия инверсий. Вывод о неслучайном изменении или нарушении однородности рядов соответствовал условию, когда расчетная статистика превышала соответствующее критическое значение при уровне значимости 0,05. Результаты. Рассмотрены особенности климата севера Западной Сибири и его изменчивость в последние годы. Исследованы изменения температуры воздуха и почвогрунтов на глубинах 160 и 320 см, продолжительность прямой солнечной радиации, суммы атмосферных осадков и высоты снежного покрова на основе инструментальных данных за последние 35 лет. В результате статистического анализа установлено сохранение темпов роста температуры воздуха в теплое время года, увеличение температуры почвогрунтов в течение всего года, выявлен зональный характер изменения суммы атмосферных осадков и снежного покрова. Микроклиматические изменения характеристик метеорологических величин могут искажать реальную картину изменения климата.The relevance of the research is related to the necessity to assess climate changes affecting the permafrost due to the possible growth of greenhouse gas emissions and increase of accident rate in industrial, oil and gas infrastructure at permafrost thawing. The aim of the research is to estimate the current changes in climate characteristics, which affect directly the thermal state of soils in permafrost areas in the north of Western Siberia. Methods. Analysis of long-term changes of meteorological data consisted of tests of null hypothesis of randomness and homogeneity of observation series and trend presence. The homogeneity test was carried out using the Abbe test, the test of randomness was carried out by Pitman criterion, the trend presence was checked using the criterion of inversions. The conclusion on nonrandom change or violation of the homogeneity of rows corresponded to the condition, when the modulus of the estimated statistics exceeded the corresponding critical value at significance level of 0,05. Results. The paper considers the climatic features in the north of Western Siberia and its variability in recent years. The analysis of temperature changes of air and soil at depths of 160 and 320 cm, the amount of precipitation and snow cover based on the instrumental data for the last 35 years has shown that air temperature continues rising in the warmer months, soil temperature increases throughout the year. The authors have revealed zonal character of changes in the amount of precipitation and snow cover. Microclimatic changes in characteristic of meteorological values can distort the real picture of climate change

    How political are national identities? A comparison of the United States, the United Kingdom, and Germany in the 2010s

    Get PDF
    This is the final version of the article. Available from SAGE Publications via the DOI in this record.Original data supporting this research are available from the UK Data Archive (Study Number 851142): http://dx.doi.org/10.5255/UKDA-SN-851142/Research demonstrates the multi-dimensional nature of American identity arguing that the normative content of American identity relates to political ideologies in the United States, but the sense of belonging to the nation does not. This paper replicates that analysis and extends it to the German and British cases. Exploratory structural equation modeling attests to cross-cultural validity of measures of the sense of belonging and norms of uncritical loyalty and engagement for positive change. In the 2010s, we find partisanship and ideology in all three nations explains levels of belonging and the two content dimensions. Interestingly, those identifying with major parties of the left and right in all three countries have a higher sense of belonging and uncritical loyalty than their moderate counterparts. The relationship between partisanship, ideology, and national identity seems to wax and wane over time, presumably because elite political discourse linking party or ideology to identity varies from one political moment to the next.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Data collection was funded by a grant from the Economic and Social Research Council of the United Kingdom (RES-061-25-0405)
    corecore