853 resultados para Compliant mechanisms
Resumo:
The European ambitious targets to increase the share of renewable generation pose a challenge to the generation adequacy. Many European member states are concerned that energy-only markets alone might not be able to deliver sufficient capacity required to meet the future electricity demand and back up shortfalls of energy from renewable energy sources (RES) during periods of low wind and sun. Many EU members consider to re-design their energy-only markets and establish different forms of capacity remunerative mechanisms (CRMs) to maintain the security of supply. There is a certain concern that market design changes at the level of EU member countries might conflict with the European goal of a single market. As soon as many European markets are highly interconnected, uncoordinated CRMs might create negative crossborder effects and hinder the achievement of the Internal Electricity Market in Europe. The pros and cons of capacity markets are well examined at the national level. However, the cross-border effects of capacity markets within the European market aiming at higher integration have received less attention. This doctoral dissertation examines the cross-border effects of unilateral implementation of CRMs applying both theoretical and case study analyses. The results show that capacity remunerative mechanisms (CRMs) may cause negative cross-border effects, especially if they are implemented unilaterally.
Resumo:
Neuropeptide Y (NPY) is a neurotransmitter promoting energy storage by activating Y-receptors and thus affecting food intake, thermogenesis and adipose tissue metabolism. NPY is expressed both in the central and sympathetic nervous system. Hypothalamic NPY is known to stimulate feeding, but the effects of noradrenergic neuron NPY are more ambiguous. Chronic stress stimulates fat accumulation via NPY release from noradrenergic neurons. Furthermore, polymorphism in the human Npy gene has been associated with metabolic disturbances and increased NPY secretion after sympathetic stimulation. The main objective of this study was to clarify the mechanisms of noradrenergic neuron NPY in the development of obesity. The metabolic phenotype of a homozygous mouse overexpressing NPY in the brain noradrenergic neurons and sympathetic nervous system (OE-NPYDβH mouse) was characterized. OE-NPYDβH mice had an increased fat mass and body weight, which caused impairments of glucose metabolism and hyperinsulinaemia with age. There were no differences in energy intake or expenditure, but the sympathetic tone was down-regulated and the endocannabinoid system activated. Furthermore, peripheral Y2-receptors in energy-rich conditions played an important role in mediating the fat-accumulating effect of NPY. These results indicate that noradrenergic neuron NPY promotes obesity via direct effects in the periphery and by modulating the sympatho-adrenal and endocannabinoid systems. Additionally, NPY in the central noradrenergic neurons is believed to possess many important roles. The phenotype of the OE-NPYDβH mouse resembles the situations of chronic stress and Npy gene polymorphism and thus these mice may be exploited in testing novel drug candidates for the treatment of obesity.
Resumo:
Resveratrol (RESV) is a polyphenolic compound found in various plants, including grapes, berries and peanuts, and its processed foods as red wine. RESV possesses a variety of bioactivities, including antioxidant, anti-inflammatory, cardioprotective, antidiabetic, anticancer, chemopreventive, neuroprotective, renal lipotoxicity preventative, and renal protective effects. Numerous studies have demonstrated that polyphenols promote cardiovascular health. Furthermore, RESV can ameliorate several types of renal injury in animal models, including diabetic nephropathy, hyperuricemic, drug-induced injury, aldosterone-induced injury, ischemia-reperfusion injury, sepsis-related injury, and endothelial dysfunction. In addition, RESV can prevent the increase in vasoconstrictors, such as angiotensin II (AII) and endothelin-1 (ET-1), as well as intracellular calcium, in mesangial cells. Together, these findings suggest a potential role for RESV as a supplemental therapy for the prevention of renal injury.
Resumo:
The paper presents the main arguments of Bresser Pereira's Globalization and Competition. Development strategies based on the 'conventional orthodoxy' are shown to carry serious drawbacks ("Dutch disease", pernicious effects of external saving, currency overvaluation), while a 'new developmentalism' is promoted, in spite of the widespread belief that the nation-states have been dispossessed of their room for manoeuvre because of the globalization process. The "new developmentalism" is based on domestic finance, balanced public budgets, moderate interest rates and competitiveness policies aimed at neutralizing the tendency to exchange rate overappreciation. The paper also points out a few theoretical questions the book raises.
Resumo:
This study discusses the interactions of different decision-making mechanisms in the process of change of a successful entrepreneurial dairy firm in Vietnam. The purpose of the study is to construct a theoretical framework, which explains the interactions between effectual and causal decision-making processes in different phases of business, and to provide a real life example with practical recommendations for entrepreneurs and managers. In order to achieve this purpose, a preliminary theoretical framework was built, using process theories applied to different decision making modes, referred to as causation and effectuation. The case was studied through ethnographic research method, with three semi-structured interviews, one unstructured interview, secondary data and observations within four months in 2013-2014. After the data was analyzed, a modified framework was drawn from the result. The finding of this study shows that there was an interaction between effectual and causal decision-making processes in different stages of the company’s development. The entrepreneur applied effectual decision-making process to develop a unique business model and a new dairy market segment. However, when a new market demand arose, the company’s resources became insufficient, they thus had to shift to causation process to adapt to market change. Simultaneously, with better-accumulated resources, the entrepreneur continued the effectuation process to create another brand new dairy market segment. This study, thus, contributes to effectuation theory, emphasizing the necessity of combining effectual and causal decision-making processes in different phases of business. It is suggested that business would develop with an effectual process until a business model is viable for growth. It continues to use this process up to a certain degree. When the market changes, the company needs to collect more means to adapt to the changes. They need to set new goals and this is a shift to the use of causal process, which builds on prediction. It uses goals and teleology as driving mechanisms and tries to exploit and fill potential resource gaps to achieve these goals. At the same time, there are new iterations that look to establish new lines or types of business with the given means, which are now well established. This again employs effectual mechanisms, which are based on evolutionary process, until they reach the stage of viable tested business model. Moreover, this study hopes to provide know-how to entrepreneurs and managers of small companies in similar situations, suggesting how to combine effectual and causal decision-making processes to deal with various circumstances in different times.
Resumo:
The quartzite microfabric found in the Lorrain Formation was studied across the La Cloche syncline, along a regional north-south transect along highway 6, near Whitefish Falls, Ontario. The complete stratigraphic sequence across the syncline is preserved, and is present on each fold limb. The lithostratigraphic units with the smallest grains size and lowest mica content are located close to the core of the fold, while coarser grained mica and feldspar rich units are situated at the northern and southern most extent of the transect. Deformation mechanisms vary with lithology and with position across the fold. Pressure solution appears to be the dominant deformation mechanism in the feldspathic, micaceous and ferruginous units. In the finer grained, mica poor white medium grained and cherty sandstone units, grain boundary migration (GBM) characteristics show dominance over those of pressure solution and show high amounts of fracturing which cut migrated boundaries and therefore post date GBM. All samples across the fold display a preferred orientation of quartz c-axes. The senses of asymmetry of fabrics are found to be similar across the syncline, with the exception of the ferruginous sandstone unit. Formation of these similar fabrics synmietries can not be the result of strain related to first order folding. The mica content appears to be related to the percentage of quartz lost due to pressure solution as a result of strain; the more mica present, the less quartz was lost. Calculations based on the shape of initial grains suggest that conservatively 30% of the quartz volume has been dissolved out of the Lorrain quartzite, and potentially migrated hundreds of meters to other members of the Huronian Supergroup as there was no meso or macroscopic evidence observed in outcrop.
Resumo:
With the relationship between endothelin-1 (ET-1) stimulation and reactive oxygen species (ROS) production unknown in adventitial fibroblasts, I examined the ROS response to ET-1 and angiotensin (Ang II). ET-1 -induced ROS peaked following 4 hrs of ET-1 stimulation and was inhibited by an ETA receptor antagonist (BQ 123, 1 uM) an extracellular signal-regulated kinase (ERK) 1/2 inhibitor (PD98059, 10 uM), and by both a specific, apocynin (10 uM), and non-specific, diphenyleneiodonium (10 uM), NAD(P)H oxidase inhibitor. NOX2 knockout fibroblasts did not produce an ET-1 induced change in ROS levels. Ang II treatment increased ROS levels in a biphasic manner, with the second peak occurring 6 hrs following stimulation. The secondary phase of Ang II induced ROS was inhibited by an ATi receptor antagonist, Losartan (100 uM) and BQ 123. In conclusion, ET-1 induces ROS production primarily through an ETA-ERKl/2 NOX2 pathway, additionally, Ang II-induced ROS production also involves an ETa pathway.
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In this quasi-experimental study, the theory of reasoned action was used as a conceptual framework to assess the outcome effect of a predialysis class. A pretest, posttest design was used to determine changes in client knowledge about their condition and its treatment, and their intention, attitudes and social norm towards compliant behaviours. The related compliant behaviours were following a low-salt diet and taking medications as proscribed. Thirty-eight End Stage Renal Diseases (ESRD) clients were self-selected into the treatment or control groups. Both groups received the standard predialysis education from members of the multidisciplinary renal team. In addition, the treatment group also attended the predialysis class. Subjects' health locus of control, anxiety and demographic variables were measured as possible extraneous variables. Study subjects from both groups demonstrated a high internal and powerful others health locus of control and a normal range of anxiety. Although not statistically significant ill = .64), the experimental group demonstrated higher knowledge level and greater intention to follow a low salt diet UL= .73). They developed more significantly positive attitudes towards following a low salt diet and increased subjective norm influence after attending the predialysis class. Attending the predialysis class did not have an effect on subjects' intentions, attitudes or subjective norm towards taking medications as prescribed. Conclusion: The predialysis class was only marginally effective in increasing client knowledge, but influenced clients' attitudes towards following a low-salt diet. Based on the results, recommendations for improvements to the class have been suggested.
Resumo:
Excess plasma free fatty acids (FFA) are correlated with insulin resistance and are a risk factor for the development of type 2 diabetes. In this study we examined the effect of the polyphenol resveratrol on FF A-induced insulin resistance in skeletal muscle cells and the mechanisms involved. Incubation of L6 myotubes with the FF A palmitate significantly decreased the insulin-stimulated glucqse uptake. Importantly, the effect of palmitate was ameliorated by resveratrol. Palmitate significantly increased serine phosphorylation of IRS..; 1 and reduced insulin-stimulated Akt phosphorylation, an effect that was abolished by resveratrol. We then investigated the effect of palmitate and resveratrol on the expression and phosphorylation of JNK, mTOR, p70-S6K, and AMPK kinases. The results demonstrated that our treatments had no effect on the expression of these proteins. However, palmitate increased the phosphorylation of mTOR and p70- S6K, whereas resveratrol abolished this effect and increased the phosphorylation of AMPK. Furthermore, all effects of resveratrol were abolished with sirtuin inhibitors, sirtinol and nicotinamide. These results indicate that resveratrol ameliorated FF A-induced insulin resistance by regulating mTOR and p70-S6K phosphorylation in skeletal muscle cells, through a mechanism involving sirtuins.
Resumo:
The Active Isolated Stretching (AIS) technique proposes that by contracting a muscle (agonist) the opposite muscle (antagonist) will relax through reciprocal inhibition and lengthen without increasing muscle tension (Mattes, 2000). The clinical effectiveness of AIS has been reported but its mechanism of action has not been investigated at the tissue level. Proposed mechanisms for increased range of motion (ROM) include mechanical or neural changes, or an increased stretch tolerance. The purpose of the study was to investigate changes in mechanical properties, i.e. stiffness, of skeletal muscle in response to acute and long-term AIS stretching for the hamstring muscle group. Recreationally active university-aged students (female n=8, male n=2) classified as having tight hamstrings, by a knee extension test, volunteered for the study. All stretch procedures were performed on the right leg, with the left leg serving as a control. Each subject was assessed twice: at an initial session and after completing a 6-week AIS hamstring stretch training program. For both test sessions active knee extension (ROM) to a position of "light irritation", passive resisted torque and stiffness were determined before and after completion of the AIS technique (2x10 reps). Data were collected using a Biodex System 3 Pro (Biodex Medical Systems, NY, USA) isokinetic dynamometer. Surface electromyography (EMG) was used to monitor vastus lateralis (VL) and hamstring muscle activity during the stretching movements. Between test sessions, 2x10 reps of the AIS bent knee hamstring stretch were performed daily for 6-weeks.
Resumo:
Arabidopsis is a model plant used to study disease resistance; Solanum tuberosum or potato is a crop species. Both plants possess inducible defense mechanisms that are deployed upon recognition of pathogen invasion. Transcriptional reprogramming is crucial to the activation of defense responses. The Pathogenesis-Related (PR) genes are activated in these defense programs. Expression of Arabidopsis PR-l and potato PR-10a serve as markers for the deployment of defense responses in these plants. PR-l expression indicates induction of systemic acquired resistance (SAR). Activation of SAR requires accumulation of salicylic acid (SA), in addition to the interaction of the non-expressor of pathogenesis-related genes I (NPRI), with the TGA transcription factors. The PR-10a is activated in response to pathogen invasion, wounding and elicitor treatment. PR-10a induction requires recruitment of the Whirly I (Whyl) activator to the promoter. This locus is also negatively regulated by the silencer element binding factor (SEBF). We established that both the PR-l and PR-10a are occupied by repressors under non-inducing conditions. TGA2 was found to be a constitutive resident and repressor of PR-l, which mediates repression by forming an oligomeric complex on the promoter. The DNA-binding activity of this oligomer required the TGA2 N-terminus (NT). Under resting conditions we determined that the PR-10a is bound by a repressosome containing SEBF and curiously the activator Pto interacting protein 4 (Pti4). In the context of this repressosome, SEBF is responsible for PR-10a binding, yet rWe also showed that PR-l and PR-10a are activated by different means. In PR-l activation the NPRI NT domain alleviates TGA2-mediated repression by interacting with the TGA2 NT. TGA2 remains at the PR-l but adopts a dimeric conformation and forms an enhanceosome with NPRl. In contrast, the PR-10a is activated by evicting the repressosome and recruiting Why! to the promoter. These results advance our understanding of the mechanisms regulating PR-l and PR-10a expression under resting and inducing conditions. This study also revealed that the means of regulation for related genes can differ greatly between model and crop s