366 research outputs found

    Melancholia

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    An Extract from a Dissertation read before the Royal Medical Society on Friday, 27th January, 1961."Melancholy," meaning "black bile" or "black despair," designates aptly that spiritual blight which has vexed mankind from the earliest time. Playwrights and philosophers have long been intrigued by the spectacle of causeless melancholy, and, more recently, pathological melancholy, rechristened "psychotic depression" has been the subject of clinical definition

    The symbiosis of concurrency and verification: teaching and case studies

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    Concurrency is beginning to be accepted as a core knowledge area in the undergraduate CS curriculum—no longer isolated, for example, as a support mechanism in a module on operating systems or reserved as an advanced discipline for later study. Formal verification of system properties is often considered a difficult subject area, requiring significant mathematical knowledge and generally restricted to smaller systems employing sequential logic only. This paper presents materials, methods and experiences of teaching concurrency and verification as a unified subject, as early as possible in the curriculum, so that they become fundamental elements of our software engineering tool kit—to be used together every day as a matter of course. Concurrency and verification should live in symbiosis. Verification is essential for concurrent systems as testing becomes especially inadequate in the face of complex non-deterministic (and, therefore, hard to repeat) behaviours. Concurrency should simplify the expression of most scales and forms of computer system by reflecting the concurrency of the worlds in which they operate (and, therefore, have to model); simplified expression leads to simplified reasoning and, hence, verification. Our approach lets these skills be developed without requiring students to be trained in the underlying formal mathematics. Instead, we build on the work of those who have engineered that necessary mathematics into the concurrency models we use (CSP, ?-calculus), the model checker (FDR) that lets us explore and verify those systems, and the programming languages/libraries (occam-?, Go, JCSP, ProcessJ) that let us design and build efficient executable systems within these models. This paper introduces a workflow methodology for the development and verification of concurrent systems; it also presents and reflects on two open-ended case studies, using this workflow, developed at the authors’ two universities. Concerns analysed include safety (don’t do bad things), liveness (do good things) and low probability deadlock (that testing fails to discover). The necessary technical background is given to make this paper self-contained and its work simple to reproduce and extend

    Pilot Study Comparing Closed Versus Open Tracheal Suctioning in Postoperative Neonates and Infants With Complex Congenital Heart Disease

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    Objectives: To determine the hemodynamic effect of tracheal suction method in the first 36 hours after high-risk infant heart surgery on the PICU and to compare open and closed suctioning techniques. Design: Pilot randomized crossover study. Setting: Single PICU in United Kingdom. Participants: Infants undergoing surgical palliation with Norwood Sano, modified Blalock-Taussig shunt, or pulmonary artery banding in the first 36 hours postoperatively. Interventions: Infants were randomized to receive open or closed (in-line) tracheal suctioning either for their first or second study tracheal suction in the first 36 hours postoperatively. Measurements and Main Results: Twenty-four infants were enrolled over 18 months, 11 after modified Blalock-Taussig shunt, seven after Norwood Sano, and six after pulmonary artery banding. Thirteen patients received the open suction method first followed by the closed suction method second, and 11 patients received the closed suction method first followed by the open suction method second in the first 36 hours after their surgery. There were statistically significant larger changes in heart rate (p = 0.002), systolic blood pressure (p = 0.022), diastolic blood pressure (p = 0.009), mean blood pressure (p = 0.007), and arterial saturation (p = 0.040) using the open suction method, compared with closed suctioning, although none were clinically significant (defined as requiring any intervention). Conclusions: There were no clinically significant differences between closed and open tracheal suction methods; however, there were statistically significant greater changes in some hemodynamic variables with open tracheal suctioning, suggesting that closed technique may be safer in children with more precarious physiology. (Pediatr Crit Care Med 2017; XX:00–00

    Bacterial Acquisition in Juveniles of Several Broadcast Spawning Coral Species

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    Coral animals harbor diverse microorganisms in their tissues, including archaea, bacteria, viruses, and zooxanthellae. The extent to which coral-bacterial associations are specific and the mechanisms for their maintenance across generations in the environment are unknown. The high diversity of bacteria in adult coral colonies has made it challenging to identify species-specific patterns. Localization of bacteria in gametes and larvae of corals presents an opportunity for determining when bacterial-coral associations are initiated and whether they are dynamic throughout early development. This study focuses on the early onset of bacterial associations in the mass spawning corals Montastraea annularis, M. franksi, M. faveolata, Acropora palmata, A. cervicornis, Diploria strigosa, and A. humilis. The presence of bacteria and timing of bacterial colonization was evaluated in gametes, swimming planulae, and newly settled polyps by fluorescence in situ hybridization (FISH) using general eubacterial probes and laser-scanning confocal microscopy. The coral species investigated in this study do not appear to transmit bacteria via their gametes, and bacteria are not detectable in or on the corals until after settlement and metamorphosis. This study suggests that mass-spawning corals do not acquire, or are not colonized by, detectable numbers of bacteria until after larval settlement and development of the juvenile polyp. This timing lays the groundwork for developing and testing new hypotheses regarding general regulatory mechanisms that control bacterial colonization and infection of corals, and how interactions among bacteria and juvenile polyps influence the structure of bacterial assemblages in corals

    Res Medica, Autumn 1961, Volume 3, Number 1

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    TABLE OF CONTENTSPERFUSION: Professor W.A. MackeyABDOMINAL CRISES 1: I.S.R. Sinclair, F.R.C.S.FIBRINOLYSIS AND OCCLUSIVE VASCULAR DISEASE: J.D. Cash, B.Sc., M.B., CH.B.RES MEDICATHE UNBORN CHILD: Professor C.S. RussellTHE USE OF CONTROLS IN THE ASSESSMENT OF CLINICAL EVIDENCE: C.V. Ruckley, M.B., CH.B."THE SLIMY MUD OF WORDS":H.C. Drysdale, M.B., CH.B.THE HARVEIAN ORATION, 1961: Dr. J.K. Slater, O.B.E., M.D.MELANCHOLIA: E.B. Ritson, M.B., CH.B

    Discovery of naked charm particles and lifetime differences among charm species using nuclear emulsion techniques innovated in Japan

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    This is a historical review of the discovery of naked charm particles and lifetime differences among charm species. These discoveries in the field of cosmic-ray physics were made by the innovation of nuclear emulsion techniques in Japan. A pair of naked charm particles was discovered in 1971 in a cosmic-ray interaction, three years prior to the discovery of the hidden charm particle, J/Ψ, in western countries. Lifetime differences between charged and neutral charm particles were pointed out in 1975, which were later re-confirmed by the collaborative Experiment E531 at Fermilab. Japanese physicists led by K.Niu made essential contributions to it with improved emulsion techniques, complemented by electronic detectors. This review also discusses the discovery of artificially produced naked charm particles by us in an accelerator experiment at Fermilab in 1975 and of multiple-pair productions of charm particles in a single interaction in 1987 by the collaborative Experiment WA75 at CERN

    Khat and alcohol use and risky sex behaviour among in-school and out-of-school youth in Ethiopia

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    BACKGROUND: Khat (an evergreen plant with amphetamine-like properties) and alcohol are widely consumed among the youth of Ethiopia. However, their relationship to risky sexual behaviour is not well described. This study was conducted to describe the magnitude of risky sexual behaviour (unprotected sex and early initiation of sexual activity) and its association with Khat and alcohol consumption in Ethiopian youths. METHODS: A probabilistic national sample of 20,434 in-school and out-of-school youths aged between 15 and 24 years of age was selected and interviewed regarding their sexual behavior and substance use. RESULTS: Over 20% of out-of-school youth had unprotected sex during the 12-month period prior to interview compared to 1.4% of in-school youth. Daily Khat intake was also associated with unprotected sex: adjusted OR (95% CI) = 2.26 (1.92, 2.67). There was a significant and linear association between alcohol intake and unprotected sex, with those using alcohol daily having a three fold increased odds compared to those not using it: adj. OR (95% CI) = 3.05 (2.38, 3.91). Use of substances other than Khat was not associated with unprotected sex, but was associated with initiation of sexual activity: adj. OR (95% CI) = 2.54 (1.84, 3.51). CONCLUSION: A substantial proportion of out-of-school youth engage in risky sex. The use of Khat and alcohol and other substances is significantly and independently associated with risky sexual behaviour among Ethiopian youths

    Character and environmental lability of cyanobacteria-derived dissolved organic matter

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    Autotrophic dissolved organic matter (DOM) is central to the carbon biogeochemistry of aquatic systems, and the full complexity of autotrophic DOM has not been extensively studied, particularly by high-resolution mass spectrometry (HRMS). Terrestrial DOM tends to dominate HRMS studies in freshwaters due to the propensity of such compounds to ionize by negative mode electrospray, and possibly also because ionizable DOM produced by autotrophy is decreased to low steady-state concentrations by heterotrophic bacteria. In this study, we investigated the character of DOM produced by the widespread cyanobacteriaMicrocystis aeruginosausing high-pressure liquid chromatography-electrospray ionization-high-resolution mass spectrometry.M. aeruginosaproduced thousands of detectable compounds in axenic culture. These compounds were chromatographically resolved and the majority were assigned to aliphatic formulas with a broad polarity range. We found that the DOM produced byM. aeruginosawas highly susceptible to removal by heterotrophic freshwater bacteria, supporting the hypothesis that this autotroph-derived organic material is highly labile and accordingly only seen at low concentrations in natural settings
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