Influence of the habitat on the potential for cannibalism and population dynamics in stream-dwelling European grayling (Thymallus thymallus L.)

Cannibalism can have major influence on fish population dynamics. A prerequisite for cannibalism is that the cannibal and the potential victim meet, and besides density effects, the encounter rate between cannibals and their victims is therefore also largely dependent on habitat use and habitat heterogeneity. In this study I quantified and compared the potential for cannibalism in stream-dwelling European grayling populations in three rivers in Jämtland by means of habitat classifications. I also analyzed population dynamic consequences of varying the potential for cannibalism in terms of intensity, using a physiological structured population model. Findings based on habitat characteristics were that the potential for cannibalism is in general not favourable in these types of streams. However, some sections had optimal conditions for cannibalism. The population dynamic model predicted that cannibalism can regulate the dynamic if sufficiently intense. It might also induce population cycles, and a fishing mortality will increase the destabilizing effect. It is the younger cohorts that drive the cycles by delayed density regulation. Cannibalism can be important to take into consideration in management actions. Hence, sections with favorable conditions for cannibalism also has a capacity for high fish production, and can thus be important as a source to less productive areas of a watercourse. Cannibalism can therefore indirectly decrease the fish density in more sections than in the few sections with favorable conditions for cannibalism. Moreover, if a population has fluctuating dynamics, some years the population will be dominated by young individuals, which not is desirable for watercourses used for sportfishing.Kannibalism har stor potential att påverka fiskpopulationers dynamik. En förutsättning för att kannibalismen skall kunna ha någon större betydelse är att lekområden, yngeluppväxtområden och vuxenhabitat antingen överlappar eller finns i nära anslutning till varandra. Syftet med denna studie var att undersöka och jämföra tre vattendrags förutsättningar för kannibalism hos strömlevande harr i Jämtland, baserat på yngel- kontra vuxenhabitatens lokalisering samt kvalitet med hjälp av fältbaserade habitatklassificeringar. För att undersöka hur dessa förutsättningar kan tänkas påverka populationsdynamiken gjordes även analyser med hjälp av en fysiologiskt strukturerad populationsmodell. Resultatet från habitatundersökningarna visade att även om det finns sektioner som har optimala egenskaper för kannibalism, så är goda förutsättningar för kannibalism inte vanligt förekommande i denna typ av vattendrag. Den populationsdynamiska modellen visade att kannibalism kan reglera dynamiken även om graden av kannibalism är låg och kan framkalla mer eller mindre regelbundna populationsfluktuationer. Ett uttag via fiske ökar den effekten ännu mer och det är de unga kohorterna som skapar cyklerna genom fördröjd täthetsregleringen. Kannibalism kan vara viktigt ur förvaltningssynpunkt även om det inte är så vanligt förekommande. Sträckor med goda förutsättningar för kannibalism har vanligen även kapacitet för hög fiskproduktion och kan således vara viktiga som källa till mindre produktiva områden av vattendraget. Kannibalism kan följaktligen minska fisktätheten på fler lokaler än på de få sektioner som har gynnsamma förutsättningar för kannibalism. Dessutom, om fluktuationer förekommer så kommer populationen vissa år att domineras av unga individer, vilket inte är önskvärt om vattendraget utnyttjas för sportfiske

The influence of social phobia in first episode of psychosis and attentional processing and the ability to use theory of mind

Chapter One: Literature Review This chapter reviews the research surrounding the prevalence of comorbid social phobia in people diagnosed with schizophrenia. It then critically evaluates the eight studies that have specifically explored the relationships, if any, between social phobia and psychotic symptoms. The review surmises that the research findings are inconsistent, which seem to be attributable to methodological differences between all the studies in terms of participant selection, chronicity of psychotic symptoms and lack of consistent measures. Chapter Two: Research Report This study investigates attentional processing, the influence of social phobia and the ability to use Theory of Mind (ToM: the ability to infer other people's mental states and behaviour) in people diagnosed with their first episode of psychosis, when compared to healthy matched controls. The results showed that the first episode group attended towards negative evaluation, somatic sensations, physical threat, but not social situation word groups. Social phobia was highly prevalent in the first episode of psychosis cohort (37%) and this anxiety disorder was unrelated to psychotic symptoms. ToM processing was impaired in the first episode group. ToM was not related to social phobia symptoms, but was related to social functioning. Chapter Three: Critical Appraisal This section presents an overview of the experiences and personal reflections of the work that constitutes this thesis and includes the main personal learning points.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Felodipine-Metoprolol Combination Tablet: Maintained Health-Related Quality of Life in the Presence of Substantial Blood Pressure Reduction

Background: Most treated hypertensive patients do not achieve adequate blood pressure (BP) control. Initiating therapy with two drugs has been suggested when BP is >20/10 mm Hg above goal. To ensure patients' compliance, such treatment needs to be well tolerated and must not compromise health-related quality of life (HRQL). The primary objective of this study was to compare the effects on HRQL of initiating treatment with felodipine + metoprolol (F+M) fixed combination tablets, or enalapril (E), or placebo (P). Methods: A total of 947 patients of both sexes with primary hypertension (diastolic BP 95 to 110 mm Hg), aged 20 to 70 years, participated in this randomized, double-blind, parallel group, 12-week, multicenter trial. Treatment was initiated with F+M 5 + 50 mg, or E 10 mg, or P. Doses were doubled after 4 or 8 weeks if diastolic BP was >90 mm Hg. The HRQL was measured at baseline and at the last visit using two validated questionnaires: the Psychological General Well-being Index (PGWB) and the Subjective Symptom Assessment Profile (SSA-P). Office BP was measured at trough, that is, 24 h after the previous dose. Results: The HRQL was high at baseline and generally well maintained during the study. For example, the mean (SD) PGWB total score was 104 (16) at baseline and 105 (16) at 12 weeks in all three treatment groups. The BP reductions after F+M (18/14 mm Hg) and E (12/9 mm Hg) were significantly greater than after P (7/7 mm Hg), and the reduction after F+M was significantly greater than after E. Conclusions: The HRQL is maintained in the presence of substantial BP reduction during antihypertensive treatment with F+M fixed combination tablets. Am J Hypertens 2005;18:1313-1319 © 2005 American Journal of Hypertension, Lt

The complexity of kidney disease and diagnosing it – cystatin C, selective glomerular hypofiltration syndromes and proteome regulation

Estimation of kidney function is often part of daily clinical practice, mostly done by using the endogenous glomerular filtration rate (GFR)-markers creatinine or cystatin C. A recommendation to use both markers in parallel in 2010 has resulted in new knowledge concerning the pathophysiology of kidney disorders by the identification of a new set of kidney disorders, selective glomerular hypofiltration syndromes. These syndromes, connected to strong increases in mortality and morbidity, are characterized by a selective reduction in the glomerular filtration of 5–30 kDa molecules, such as cystatin C, compared to the filtration of small molecules <1 kDa dominating the glomerular filtrate, for example water, urea and creatinine. At least two types of such disorders, shrunken or elongated pore syndrome, are possible according to the pore model for glomerular filtration. Selective glomerular hypofiltration syndromes are prevalent in investigated populations, and patients with these syndromes often display normal measured GFR or creatinine-based GFR-estimates. The syndromes are characterized by proteomic changes promoting the development of atherosclerosis, indicating antibodies and specific receptor-blocking substances as possible new treatment modalities. Presently, the KDIGO guidelines for diagnosing kidney disorders do not recommend cystatin C as a general marker of kidney function and will therefore not allow the identification of a considerable number of patients with selective glomerular hypofiltration syndromes. Furthermore, as cystatin C is uninfluenced by muscle mass, diet or variations in tubular secretion and cystatin C-based GFR-estimation equations do not require controversial race or sex terms, it is obvious that cystatin C should be a part of future KDIGO guidelines.publishedVersio

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

10000 mechanics problems at the press of a button

Problem solving is at the heart of the mechanics curriculum, and developing problem solving skills is an important learning objective in basic and advanced mechanics courses at the undergraduate level. In alignment with this tradition, written examinations are mainly designed to test problem solving capabilities. Despite the fact that students spend most of their mechanics studies solving mechanics problems, an alarming fraction of them fail the written examination. One possible explanation is that a problem solving infrastructure, e.g. answers to problems and opportunities for collaboration with fellow students, is provided during the study period of courses, but missing during the examination

10000 mechanics problems at the press of a button

Problem solving is at the heart of the mechanics curriculum, and developing problem solving skills is an important learning objective in basic and advanced mechanics courses at the undergraduate level. In alignment with this tradition, written examinations are mainly designed to test problem solving capabilities. Despite the fact that students spend most of their mechanics studies solving mechanics problems, an alarming fraction of them fail the written examination. One possible explanation is that a problem solving infrastructure, e.g. answers to problems and opportunities for collaboration with fellow students, is provided during the study period of courses, but missing during the examination

Acceleration of continuous-time, high-cycle fatigue constrained problems in topology optimization

An efficiency-enhanced procedure to treat continuous-time, high-cycle fatigue (HCF) constraints in topology optimization is presented. The HCF model predicts the evolution of fatigue damage at each point in the design domain using a system of ordinary differential equations. We employ gradient-based optimization and the fatigue sensitivities are determined using adjoint sensitivity analysis. As the predicted damage has history dependence, adjoint variables are solved via a stepwise backward procedure. Therefore, the computational cost increases in proportion to the number of time steps. To reduce this cost, we propose an extrapolation technique which is valid for all forms of periodic, proportional loads and most non-proportional loads and allows treatment of essentially an unlimited number of load cycles. Using this technique, several problems in both 2D and 3D are solved numerically where the objective is to minimize structural mass subjected to a fatigue constraint.Funding Agencies|Sweden?s Innovation Agency [2016-05175]</p

Continuous-time, high-cycle fatigue model: Validity range and computational acceleration for cyclic stress

The properties of the continuous-time, high-cycle fatigue model of Ottosen et al. (2008) is investigated for challenging stress states. We derive an analytical solution to the damage per cycle for cyclic, proportional stress. Numerical investigations for 7050-T7451 aluminum alloy and AISI 4340 steel alloy show exponential convergence to a constant damage per cycle for cyclic proportional stress, and Wynns epsilon algorithm for sequence acceleration improves the convergence rate. Fatigue damage is well predicted for an applied proportional stress, but damage is severely underpredicted for rotary stress states or combinations of tension/compression and torsion.Funding Agencies|Clean Sky 2 joint undertaking under the European Unions Horizon 2020 research and innovation program [738002]; Swedens innovation agency [2016-05175]</p