888 research outputs found

    System architecture evaluation using modular performance analysis: a case study

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    Performance analysis plays an increasingly important role in the design of embedded real-time systems. Time-to-market pressure in this domain is high while the available implementation technology is often pushed to its limit to minimize cost. This requires analysis of performance as early as possible in the life cycle. Simulation-based techniques are often not sufficiently productive. We present an alternative, analytical, approach based on Real-Time Calculus. Modular performance analysis is presented through a case study in which several candidate architectures are evaluated for a distributed in-car radio navigation system. The analysis is efficient due to the high abstraction level of the model, which makes the technique suitable for early design exploratio

    The New ‘Coimbra Method’: A Biologically Appropriate Method for Recording Specific Features of Fibrocartilaginous Entheseal Changes

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    A working group was established in 2009 during a workshop in Coimbra, Portugal to review the various methodologies used to record entheseal changes (EC), and develop a standardized system to facilitate comparisons across studies. This paper presents the first results of the “Coimbra method”; a new qualitative method for recording fibrocartilaginous entheses based on the types of changes observed. Materials and Methods: The new method divides the enthesis into a margin (only the area opposite the acute angle of fibre attachment) and surface (which also includes the remaining margin). Five features are recorded: bone formation, erosion, fine porosity, macroporosity, and cavitation. A total of 67 male skeletons from the identified SIMON collection, Geneva, Switzerland all of whom were manual workers and aged between 20 and 79 years, were used for this study. Six skeletons were used by the authors as exemplars to determine standard criteria for recording each change. Thirty male skeletons were selected to test intra- and inter-observer error of the new method. An additional 31 skeletons were used for a preliminary test of the relationship between EC and age, using exploratory statistics and ordinal regression. Results: Intra- and inter-observer error had a similar percentage agreement of around 70%. The exploratory statistics indicated a general trend for increased scores of each feature with age, but ordinal regression demonstrated that this was not statistically significant (p<0.05) for all features. Discussion: The recording method is repeatable for some entheses. The effect of the ageing process is dependent on enthesis and EC feature. Unlike most methods, the “Coimbra method” records EC features in detail; this has the advantage of allowing studies of the relationship between different EC and age, as well as sex and occupation. Further studies on larger identified skeletal collections are needed to test the effect of age, sex and occupation.

    Chronobiopsychosocial perspectives of old age major depression: A randomized placebo controlled trial with bright light

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    Hoogendijk, W.J.G. [Promotor]Beekman, A.T.F. [Promotor

    Patients with chronic gastrointestinal ischemia have a higher cardiovascular disease risk and mortality

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    Objectives: We determined the prevalence of classical risk factors for atherosclerosis and mortality risk in patients with CGI. Methods: A case-control study was conducted. Patients referred with suspected CGI underwent a standard work-up including risk factors for atherosclerosis, radiological imaging of abdominal vessels and tonometry. Cases were patients with confirmed atherosclerotic CGI. Controls were healthy subjects previously not known with CGI. The mortality risk was calculated as standardized mortality ratio derived from observed mortality, and was estimated with ten-year risk of death using SCORE and PREDICT. Results: Between 2006 and 2009, 195 patients were evaluated for suspected CGI. After a median follow-up of 19 months, atherosclerotic CGI was diagnosed in 68 patients. Controls consisted of 132 subjects. Female gender, diabetes, hypercholesterolemia, a personal and family history of cardiovascular disease (CVD), and current smoking are highly associated with CGI. After adjustment, female gender (OR 2.14 95% CI 1.05-4.36), diabetes (OR 5.59, 95% CI 1.95-16.01), current smoking (OR 5.78, 95% CI 2.27-14.72), and history of CVD (OR 21.61, 95% CI 8.40-55.55) remained significant. CGI patients >55 years had a higher median ten-year risk of death (15% vs. 5%, P = 0.001) compared to controls. During follow-up of 116 person-years, standardized mortality rate was higher in CGI patients (3.55; 95% CI 1.70-6.52). Conclusions: Patients with atherosclerotic CGI have an increased estimated CVD risk, and severe excess mortality. S

    Dental calculus is not equivalent to bone collagen for isotope analysis: a comparison between carbon and nitrogen stable isotope analysis of bulk dental calculus, bone and dentine collagen from same individuals from the Medieval site of El Raval (Alicante, Spain).

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    Palaeodietary reconstruction using the carbon and nitrogen isotope values of bone and dentine collagen is a well-established method and the biochemical processes involved are well known. Researchers have recently explored using bulk samples of dental calculus as a substitute for bone and dentine collagen in dietary analyses, because calculus can be sampled without causing damage to the teeth, and may be useful in situations where more destructive analyses are not possible, or where collagen is poorly preserved. Several questions remain about the use of bulk calculus as a source of carbon and nitrogen isotope data, however. It is not yet clear how much of an individual¿s life span dental calculus represents, what portions of the diet it records, and how diagenesis effects the carbon and nitrogen isotope values of this material. Most importantly, there have been no comparative studies of collagen and calculus isotope values, which are necessary to establish the value of bulk calculus as a source of accurate isotope values. Here we report the comparison of carbon and nitrogen stable isotope analyses of bulk calculus to those from bone and dentine collagen. These analyses have been performed on individuals from the El Raval Mudéjar Medieval Cemetery (Eastern Iberia, 15th century A.D.). Although calculus isotope values may be broadly similar to expected values at the population level, we report here no correlation between collagen and bulk dental calculus values at the individual level. As a result, we recommend that carbon and nitrogen analysis on bulk dental calculus should only be used as a last resource archaeological dietary marker, if at all

    Integrating isotopes and documentary evidence : dietary patterns in a late medieval and early modern mining community, Sweden

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    We would like to thank the Archaeological Research Laboratory, Stockholm University, Sweden and the Tandem Laboratory (Ångström Laboratory), Uppsala University, Sweden, for undertaking the analyses of stable nitrogen and carbon isotopes in both human and animal collagen samples. Also, thanks to Elin Ahlin Sundman for providing the δ13C and δ15N values for animal references from Västerås. This research (Bäckström’s PhD employment at Lund University, Sweden) was supported by the Berit Wallenberg Foundation (BWS 2010.0176) and Jakob and Johan Söderberg’s foundation. The ‘Sala project’ (excavations and analyses) has been funded by Riksens Clenodium, Jernkontoret, Birgit and Gad Rausing’s Foundation, SAU’s Research Foundation, the Royal Physiographic Society of Lund, Berit Wallenbergs Foundation, Åke Wibergs Foundation, Lars Hiertas Memory, Helge Ax:son Johnson’s Foundation and The Royal Swedish Academy of Sciences.Peer reviewedPublisher PD

    Prior consumption of a fat meal in healthy adults modulates the brain’s response to fat

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    Background: Consumption of fat is regulated by reward and homeostatic pathways, but no studies have examined the role of the intake of a high fat meal (HFM) on subsequent brain activation to oral stimuli. Objective: We evaluated how prior consumption of a HFM or water load (WL) modulates reward, homeostatic and taste brain responses to subsequent delivery of oral fat. Methods: A randomized 2-way crossover design (1-week apart) was used to compare prior consumption of a 250mL HFM (520kcal) (rapeseed oil (440kcal), emulsifier, sucrose, flavor cocktail) or non-caloric WL on brain activation to the delivery of repeated trials of an oral flavored no-fat control stimulus (CS) or flavored fat stimulus (FS) in 17 healthy adults (11 male, age=25±2 years, BMI=22.4±0.8kg/m2). Analyses tested differences in brain activation to the CS and FS, and baseline cerebral blood flow (CBF), following the HFM and WL. Individual’s plasma cholecystokinin (CCK) concentration following the HFM was correlated with their BOLD activation. Results: Prior consumption of the HFM compared to the WL led to decreased anterior insula taste activation in response to both the CS (36.3%,P<0.05) and FS (26.5%,P<0.05). The HFM caused reduced amygdala activation (25.1%,P<0.01) in response to the FS compared to the CS (fat-related satiety). Baseline CBF significantly reduced in taste (insula (5.7%,P<0.01)), homeostatic (hypothalamus (9.2%,P<0.01), thalamus (5.1%,P<0.05))), and reward areas (striatum (9.2%,P<0.01)) following the HFM. Individual’s plasma CCK concentration negatively correlated with brain activation in taste, oral somatosensory and reward areas. Conclusions: To reduce obesity, policy in industry is to lower the fat content of foods. Our results in healthy adults show that a HFM suppresses BOLD activation in taste and reward areas compared to a WL. This understanding will help inform the reformulation of reduced-fat foods that mimic the brain’s response to high fat counterparts, and guide future interventions to reduce obesity
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