Globally the amount of electricity produced each year is increasing significantly. Between 1980 and 2010 the average increase was 407 billion kWh per year. To be able to meet this increasing electricity demand, without burdening the environment in a too large extent, the research and development of renewable energy production techniques is of great importance. In the light of this we wanted to dedicate our master thesis to help SubseaTechnology Scandinavia AB with the development of a vertical axis tidal current turbine. The project set out to do the initial design proposal of a 2 x 4 meter H-shaped Darrieus turbine by applying the Double Multiple Streamtube model. The optimization process was performed with the aid of MATLAB for four different foils. The study included two symmetrical foils; NACA 0012 and S-1046 together with two asymmetrical foils; S-1210 and E216. The parameters studied were the number of blades, chord length, tip speed ratio, fixed pitch and the operational range. In the project, effects such as blade to wake interaction, torque fluctuations etc. were also considered. From the simulations the two bladed turbine fitted with the S-1046 hydrofoil showed the highest performance but was struggling with an unfavorable oscillating torque. In the light of this the three bladed turbine fitted with the S-1046 hydrofoil with a chord of 0.13 m and an optimal tip speed ratio of 3.2 was determined. From the simulations the power coefficient reached 53.47 % for this case. This configuration also showed good performance in a relatively wide range of both tip speed ratios and free stream velocities. The model does not include several effects causing losses and the power coefficients calculated in this model are to be used as a comparison between the different turbine configurations and not as absolute values of performance. The simulations showed good potential for the use of asymmetrical foils in vertical axis turbines. The performance was evaluated for the upstream half of the turbine where the E216 foil exceeded the symmetrical foils in the range of ten percentage points.

There is now considerable evidence that both schizophrenia and affective disorders have their origin at least in part in events that occur during early pre- and post-natal development. In the case of schizophrenia, many observations, for example, increased risk for schizophrenia in the offspring of mothers who had influenza A during their second trimester of pregnancy and evidence for abnormal neuronal migration in the cerebral cortex of post mortem tissue from schizophrenic patients, suggest that a second trimester insult may have occurred and that this insult may have increased the risk for the development of schizophrenia in late adolescence or early adulthood. Animal studies have found that rats that undergo excitotxic damage to the ventral hippocampus on postnatal day 7 develop exaggerated sensitivity to dopamine-stimulating drugs or to stressful stimuli that becomes apparent after sexual maturity but not before, providing a neurodevelopmental model of schizophrenia. Similarly, post-weaning social isolation leads to nehanced responses to dopaminergic drgus and to stress that emerges after sexual maturity. These animal models are proving to be valuable tools to study the neurobiological mechanisms mediating the influence of early insults to the nervous system on later behavioural functins. In the case of affective disorders, although the evidence is not as strong, a number of the same observations have been made suggesting that an insult during early ontogeny may lead to the development of affective disorders later in life. For example, retrospective studies of people with affective disorders showed that they were more likely to have attained motor milestones at a later age and to have had poorer academic performance as children. There is a wealth of evidence suggesting hyperfunctioning of the hypothalamic-pituitary-adrenal (HPA) axis in affective disorders. Animal studies have shown that early matenal deprivation can lead to lasting changes in the reactivity of the HPA axis to stressful stimuli, providing another link from early experience to adult psychopathology. Continued studies of the effects of pre- and early post-natal events on the development of the nervous system and the relationships of these events to schizophrenia or affective disorder will provide new insights into the mechanisms underlying these common neuropsychiatric illnesses.

No description available.

This paper presents the development of the curatorial research project Black Box, which was established in the spring of 2020 in the Brno TIC Gallery to support contemporary art and artists at a time when artists and cultural institutions were affected by the existential crisis caused by the COVID-19 global pandemic. This experimental archive, which initially appeared to be temporary, has been developing its activities for a second year in a row. This text aims to provide a report on the ongoing remakes and postproductions of this archive and present various curatorial interventions carried out on the archived works of the participating artists. We observe a shift of exhibition institutions towards community centres with a diversified program, raising their social awareness and critical self-reflection, and building new means of communication on the axis of the artist-spectator. Especially in the latter area, creating and enabling access to an art archive is an essential tool.

Purpose/Hypothesis: Mal de Debarquement Syndrome (MdDS) is a rare condition in which those afflicted perceive a chronic rocking or swaying sensation, often relieved when in motion and symptomatic when still. Etiology is uncertain; therefore, treatment options are limited. While there is reported success with medication, optokinetic stimulation or transcutaneous magnetic stimulation, there is no single treatment that works for all patients. This retrospective chart review investigated rehabilitation outcomes following sensorimotor, multi-axis, rotational (SMART) training to address MdDS symptoms. Number of Subjects: Forty-nine Materials and Methods: Forty-nine patients participated in 10-20 sessions of SMART training, with integrated use of a visual targeting system and physical therapy. Between sessions, patients were instructed to perform mindfulness breathing, relaxation and grounding techniques. Pre- and post-training Dizziness Handicap Inventory (DHI), 4-item Dynamic Gait Index (DGI), and computerized posturography including Sensory Organization Test (SOT) were assessed. Subjective change following rehabilitation was tracked at discharge, 5 weeks, 3 months, 6 months and 1 year post-training. Results: Mean age (SD) of patients was 52.9 (12.6) years with the majority (n=47) being female. Mean time from onset of symptoms (SD) was 50.8 (87.8) months suggesting chronic symptoms. At discharge, 42 of 49 patients reported improvements, with nearly half (n=24, 48.9%) of all patients reporting marked or moderate improvement in symptoms; whereas, 14 (28.6%) reported minimal improvement in symptoms. Based on paired t-tests, all outcome measures – DHI, MdDS severity Visual Analog Scale (VAS), Motion VAS, 4-item DGI, and SOT - improved significantly (p < 0.001) from initial evaluation to discharge. Several personal factors were associated with rehabilitation outcomes based on bivariate correlations. With some variation, patients sustaining improvements at 1 week post-discharge, generally continued to sustain at 5 weeks, 3 months, 6 months and 1 year. Conclusions: SMART training plus physical therapy resulted in improved performance outcomes and in significant reduction or resolution in MdDS symptoms. This study provides early evidence that this method of training has promising potential to aid in the management or recovery of MdDS. Clinical Relevance: MdDS is disorder with no specific cure. Treatment is limited. SMART training may serve as an effective outcome to reduce or resolve symptoms associated with MdDS.

No description available.

Linear-motion compliant mechanisms have generally been developed for small displacement applications. The objective of the thesis is to provide a basis for improved large-displacement linear-motion compliant mechanisms (LLCMs). One of the challenges in developing large-displacement compliant mechanisms is the apparent performance tradeoff between displacement and off-axis stiffness. In order to facilitate the evaluation, comparison, and optimization of the performance of LLCMs, this work formulates and presents a set of metrics that evaluates displacement and off-axis stiffness. The metrics are non-dimensionalized and consist of the relevant characteristics that describe mechanism displacement, off-axis stiffness, actuation force, and size. Displacement is normalized by the footprint of the device. Transverse stiffness is normalized by a new performance characteristic called virtual axial stiffness. Torsional stiffness is normalized by a performance characteristic called the characteristic torque. Because large-displacement compliant mechanisms are often characterized by non-constant axial and off-axis stiffnesses, these normalized stiffness metrics are formulated to account for the variation of both axial and off-axis stiffness over the range of displacement. In pursuit of mechanisms with higher performance, this work also investigates the development of a new compliant mechanism element. It presents a pseudo-rigid-body model (PRBM) for rolling-contact compliant beams (RCC beams), a compliant element used in the RCC suspension. The loading conditions and boundary conditions for RCC beams can be simplified to an equivalent cantilever beam that has the same force-deflection characteristics as the RCC beam. Building on the PRBM for cantilever beams, this paper defines a model for the force-deflection relationship for RCC beams. Included in the definition of the RCC PRBM are the pseudo-rigid-body model parameters that determine the shape of the beam, the length of the corresponding pseudo-rigid-body links and the stiffness of the equivalent torsional spring. The behavior of the RCC beam is parameterized in terms of a single parameter defined as clearance, or the distance between the contact surfaces. The RCC beams exhibit a unique force-displacement curve where the force is inversely proportional to the clearance squared. The RCC suspension is modeled using the newly defined PRBM. The suspension exhibits unique performance, generating no resistance to axial motion while providing significant off-axis stiffness. The mechanism has a large range of travel and operates with frictionless motion due to the rolling-contact beams. In addition to functioning as a stand-alone linear-motion mechanism, the RCC suspension can be configured with other linear mechanisms in superposition to improve the off-axis stiffness of other mechanisms without affecting their axial resistance.

Collision detection between deforming models is a difficult problem for collision detection systems to handle. This problem is even more difficult when deformations are unconstrained, objects are in close proximity to one another, and when the entity count is high. We propose a method to perform collision detection between multiple deforming objects with unconstrained deformations that will give good results in close proximities. Currently no systems exist that achieve good performance on both unconstrained triangle level deformations and deformations that preserve edge connectivity. We propose a new system built as a combination of Graphics Processing Unit (GPU) based culling and Axis Aligned Bounding Box (AABB) based culling. Techniques for performing hierarchy-less GPU-based culling are given. We then discuss how and when to switch between GPU-based culling and AABB based techniques.

PURPOSE OF REVIEW: This review article aims to explore the GI changes induced by SARS-CoV-2 and how gut microbial homeostasis can influence these changes and affect the lung-gut axis and its relationship with the induction of the cytokine release syndrome in severe COVID-19 patients. RECENT FINDINGS: Coronavirus disease 2019 (COVID-19) affects not only the respiratory system but can produce multi-systemic damage. The expression of angiotensin-converting enzyme 2 (ACE-2) receptors in the gastrointestinal (GI) tract, the high prevalence of GI symptoms in severely ill COVID-19 patients, and the abnormalities described in the gut microbiome in these patients have raised concerns about the influence of GI tract as a risk factor or as a potential modulator to reduce the severity of COVID-19. Understanding the mechanisms by which gut dysbiosis may influence viral transmission and disease progression in COVID-19 may help in shaping how accessible therapies, like diet modulation, can potentially help beat the devastating consequences of COVID-19.

There is increasing recognition of the relationship between depression and obesity in the pediatric population and recently, there has been a focus on inflammation as a potential link. Both conditions are considered to be pro-inflammatory states, and certain inflammatory markers are linked to depression in obese adults and vice versa. Leptin has also been implicated in depression as a potential mediator between inflammation and depression. Brain derived neurotrophic factor (BDNF), which is associated with depression and obesity, is influenced by inflammation and leptin in animal models as well. Few studies have examined the interactions between depression, adiposity, and biological markers in obese youth and therefore, our objective was to explore the determinants of depression in obese youth in a clinical setting. We studied 244 youth aged 8-17 years (125 girls, 119 boys) at the time of entry to a weight management program, as part of a prospective, longitudinal study. The CES-DC depression-screening tool was used to assess depressive symptoms, and a participant was classified as having high depressive symptoms if the CES-DC score ≥15 or taking antidepressants. Questionnaires assessed socio-demographic factors and puberty while adiposity was measured using dual-energy X-ray absorptiometry (DXA). Inflammatory markers (IL-6, TNFα, CRP, IL-10), leptin, and BDNF were quantified by immunoassays. Of the 244 participants, 8 were on antidepressants and 88 (36.4%) met the criteria for high depressive symptoms. We confirmed previous findings that household income and body fat were important determinants of depressive symptoms. However for the first time, it was identified that leptin levels predicted CES-DC score independent of body fat. Neither inflammatory markers nor BDNF were significantly related to depression scores. Our findings suggest that leptin may mediate the relationship of adiposity and depression but it is uncertain if this is related to direct action or to the phenomenon of leptin resistance. / Thesis / Master of Science (MSc) / Obesity has a significant impact on depression in children and adolescents. Inflammation – the body’s response to injury – is measured through markers in the blood and leptin – the marker of body fat – have shown to be related to depression. Research indicates that depression influences these factors to act on obesity. However, research on the interactions of biological and socio-demographic factors with depression in youth with obesity is lacking. Therefore, our objective was to explore the impact of these factors on depression in obese youth entering into a weight management program. Using a depression-screening tool, we studied 244 youth under 18 years and confirmed that household income and body fat were important factors of depression. However for the first time, we found leptin influenced depression regardless of the amount of fat present suggesting that depression acts on obesity through leptin but it is uncertain how this occurs and further research is warranted.