977 resultados para Weak Isometry


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This thesis concerns the role of scientific expertise in the decision-making process at the Swiss federal level of government. It aims to understand how institutional and issue-specific factors influence three things: the distribution of access to scientific expertise, its valuation by participants in policy for- mulation, and the consequence(s) its mobilization has on policy politics and design. The theoretical framework developed builds on the assumption that scientific expertise is a strategic resource. In order to effectively mobilize this resource, actors require financial and organizational resources, as well as the conviction that it can advance their instrumental interests within a particular action situation. Institutions of the political system allocate these financial and organizational resources, influence the supply of scientific expertise, and help shape the venue of its deployment. Issue structures, in turn, condition both interaction configurations and the way in which these are anticipated by actors. This affects the perceived utility of expertise mobilization, mediating its consequences. The findings of this study show that the ability to access and control scientific expertise is strongly concentrated in the hands of the federal administration. Civil society actors have weak capacities to mobilize it, and the autonomy of institutionalized advisory bodies is limited. Moreover, the production of scientific expertise is undergoing a process of professionalization which strengthens the position of the federal administration as the (main) mandating agent. Despite increased political polarization and less inclu- sive decision-making, scientific expertise remains anchored in the policy subsystem, rather than being used to legitimate policy through appeals to the wider population. Finally, the structure of a policy problem matters both for expertise mobilization and for the latter's impact on the policy process, be- cause it conditions conflict structures and their anticipation. Structured problems result in a greater overlap between the principal of expertise mobilization and its intended audience, thereby increasing the chance that expertise shapes policy design. Conversely, less structured problems, especially those that involve conflicts about values and goals, reduce the impact of expertise.

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The in vitro trypanocidal activity of 22 extracts and 43 fractions of plants belonging to the families Meliaceae and Rutaceae was evaluated. The extracts from leaves of Conchocarphus heterophyllus and branches of Trichilia ramalhoi were the most active. The trypanocidal activity seems to be increased by fractionation of the extracts. Fractions from C. heterophyllus and Galipea carinata were the most active and a 100% lysis of the parasites was observed for five fractions. From one of them were isolated two flavonoids: flavone and 7-methoxyflavone, which showed weak trypanocidal activity. The results obtained from the extracts and fractions revealed that the order Rutales is a promising source for the search of new drugs for Chagas disease. Phytochemical studies with the other active fractions are underway in order to isolate compounds, which could be associated with observed activities.

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BACKGROUND: Evidence is accumulating that telomere length is a good predictor of life expectancy, especially early in life, thus calling for determining the factors that affect telomere length at this stage. Here, we investigated the relative influence of early growth conditions and origin (genetics and early maternal effects) on telomere length of collared flycatchers (Ficedula albicollis) at fledging. We experimentally transferred hatchlings among brood triplets to create reduced, control (i.e. unchanged final nestling number) and enlarged broods. RESULTS: Although our treatment significantly affected body mass at fledging, we found no evidence that increased sibling competition affected nestling tarsus length and telomere length. However, mixed models showed that brood triplets explained a significant part of the variance in body mass (18%) and telomere length (19%), but not tarsus length (13%), emphasizing that unmanipulated early environmental factors influenced telomere length. These models also revealed low, but significant, heritability of telomere length (h(2) = 0.09). For comparison, the heritability of nestling body mass and tarsus length was 0.36 and 0.39, respectively, which was in the range of previously published estimates for those two traits in this species. CONCLUSION: Those findings in a wild bird population demonstrate that telomere length at the end of the growth period is weakly, but significantly, determined by genetic and/or maternal factors taking place before hatching. However, we found no evidence that the brood size manipulation experiment, and by extension the early growth conditions, influenced nestling telomere length. The weak heritability of telomere length suggests a close association with fitness in natural populations.

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An effective vaccine against schistosomiasis mansoni would be a valuable control tool and the high levels of protection elicited in rodents and primates by radiation-attenuated cercariae provide proof of principle. A major obstacle to vaccine development is the difficulty of identifying the antigens that mediate protection, not least because of the size of the genome at 280Mb DNA encoding 14,000 to 20,000 genes. The technologies collectively called proteomics, including 2D electrophoresis, liquid chromatography and mass spectrometry, now permit any protein to be identified provided there is extensive DNA data, and preferably a genome sequence. Applied to soluble (cytosolic) proteins from schistosomes, proteomics reveals the great similarity in composition between life cycle stages, with several WHO vaccine candidates amongst the most abundant constituents. The proteomic approach has been successfully applied to identify the secretions used by cercaria to penetrate host skin, the gut secretions of adult worms and the proteins exposed on the tegument surface. Soluble proteins can also be separated by 2D electrophoresis before western blotting to identify the full range of antigenic targets present in a parasite preparation. The next step is to discover which target proteins represent the weak points in the worm's defences.

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Aquest treball aprofundeix en el Departament d'Educació com a gran empresa, n'analitza els objectius, les funcions i l'estructura organitzativa i estudia els avantatges que podria aportar la implantació d'un ERP. També estudia amb detall els passos que s'haurien de seguir per a implantar SAP R/3 i n'assenyala els punts febles per tal de prevenir-los i assegurar l'èxit de la implantació.

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A new and original reagent based on the use of highly fluorescent cadmium telluride (CdTe) quantum dots (QDs) in aqueous solution is proposed to detect weak fingermarks in blood on non-porous surfaces. To assess the efficiency of this approach, comparisons were performed with one of the most efficient blood reagents on non-porous surfaces, Acid Yellow 7 (AY7). To this end, four non-porous surfaces were studied, i.e. glass, transparent polypropylene, black polyethylene, and aluminium foil. To evaluate the sensitivity of both reagents, sets of depleted fingermarks were prepared, using the same finger, initially soaked with blood, which was then successively applied on the same surface without recharging it with blood or latent secretions. The successive marks were then cut in halves and the halves treated separately with each reagent. The results showed that QDs were equally efficient to AY7 on glass, polyethylene and polypropylene surfaces, and were superior to AY7 on aluminium. The use of QDs in new, sensitive and highly efficient latent and blood mark detection techniques appears highly promising. Health and safety issues related to the use of cadmium are also discussed. It is suggested that applying QDs in aqueous solution (and not as a dry dusting powder) considerably lowers the toxicity risks.

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L'objecte d'aquest treball és el d'analitzar les pràctiques i estratègies que es segueixen quant a l'adquisició de les Tecnologies de la Informació i la Comunicació (TIC) en l'àmbit de l'Administració Local de la província de Guadalajara i fer una valoració-punts forts i febles-de les mateixes.

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This study demonstrates that the expression of the peroxisome proliferator-activated receptor alpha (PPAR alpha) is regulated by glucocorticoid hormones in hepatocytes. Hydrocortisone, dexamethasone, and triamcinolone stimulated PPAR alpha mRNA synthesis in a dose-dependent manner in primary rat hepatocyte cultures. This glucocorticoid stimulation was inhibited by RU 486, a specific glucocorticoid antagonist. Moreover, in contrast to glucocorticoid hormones, the mineralocorticoid aldosterone had only a weak effect, suggesting that the hormonal stimulation of PPAR alpha was mediated by the glucocorticoid receptor. The induction was not prevented by cycloheximide treatment of the hepatocytes, indicating that it was mediated by preexisting glucocorticoid receptor. Finally, the RNA synthesis inhibitor actinomycin D abolished the stimulatory effect of dexamethasone, and nuclear run-on analysis showed an increase of PPAR alpha transcripts after hormonal induction. Thus, the PPAR alpha gene is an early response gene of glucocorticoids that control its expression at the transcriptional level.

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The plasma concentrations of alpha 1-acid glycoprotein (AAG), albumin, triglycerides, cholesterol, and total proteins, as well as the plasma binding of racemic, d-methadone, and l-methadone were measured in 45 healthy subjects. The AAG phenotypes and the concentrations of AAG variants were also determined. The measured free fractions for racemic, d-methadone, and l-methadone were, respectively, 12.7% +/- 3.3%, 10.0% +/- 2.9%, and 14.2% +/- 3.2% (mean +/- SD). A significant correlation was obtained between the binding ratio (B/F) for dl-methadone and the total AAG concentration (r = 0.724; p less than 0.001). A multiple stepwise regression analysis showed that AAG was the main explanatory variable for the binding of the racemate. When concentrations of AAG variants were considered, a significant correlation was obtained between the binding ratio of dl-methadone and orosomucoid2 A concentration (r = 0.715; p less than 0.001), a weak correlation between dl-methadone and orosomucoid1 S concentration (r = 0.494; p less than 0.001), and no correlation between dl-methadone and orosomucoid1 F1 concentration (r = 0.049; not significant). Similar findings were obtained with the enantiomers. This study shows the importance of considering not only total AAG but also concentrations of AAG variants when measuring the binding of methadone and possibly of other drugs in plasma.

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Tamoxifen (tam) is a widely used endocrine therapy in the treatment of early and advanced stage breast cancer in women and men. It is a pro-drug having weak affinity with the estrogen receptor and needs to be converted to its main metabolite, endoxifen (endox), to have full anticancer activity. Cytochrome 2D6 (CYP2D6) plays a major role in the metabolism of tamoxifen to endoxifen. It is genetically highly polymorphic and its activity influences profoundly the synthesis of endoxifen and potentially the efficacy of tamoxifen treatment. Genotyping is currently the most widely used approach in studies and also in clinical practice to categorize patients as poor- (PM), intermediate- (IM), extensive- (EM) and ultra rapid-metabolizers (UM). Some clinicians already use genotyping in order to tailor the endocrine therapy of their patients. Owing to the large inter-individual variations in concentrations of the active moitey due to genetic and non-genetic influences renders the predictive value of the test uncertain for an individual patient. A significant number of patients classified as EM or IM by genotyping have indeed relatively low endoxifen levels similar to PMs1. This suggests that genotyping is probably not the opti ma l meth o d f or predi cti ng end oxif en l evels.

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The aromatase inhibitor formestane (4-hydroxy-androst-4-ene-3,17-dione, F) is prohibited in sports by the World Anti-Doping Agency (WADA). F possesses only weak androgenic properties and is presumed to be employed in order to suppress estrogen production during the illicit intake of anabolic steroids by athletes. Former studies additionally showed that F is an endogenous steroid produced in low amounts. According to the regulations of WADA, urinary concentrations above 100 ng/ml are assumed to be due to ingestion of F. To distinguish between endogenous or exogenous sources of urinary F, isotope ratio mass spectrometry (IRMS) is the method of choice. Therefore, a method to determine the carbon isotope ratio (CIR) of F in urine samples was developed and validated. Routine samples (n = 42) showing concentrations of F above 5 ng/ml were investigated and enabled elucidation of the CIR of endogenous F and subsequent the calculation of a reference limit. A reference population encompassing n = 90 males and females was investigated regarding endogenous concentrations of F. An excretion study with one male volunteer was conducted to test and validate the developed method and to identify possible impact of F administration on other endogenous steroids. By CIR determination of F it is clearly possible to elucidate its endogenous or exogenous source. Taking into account the CIR of other target analytes like testosterone, a differentiation between F and androstenedione intake is possible. In 2011, the first exogenous F below the WADA threshold could be detected by means of the developed IRMS method.

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We build a theoretical framework that allows for endogenous conflict behaviour (i.e., fighting efforts) and for endogenous natural resource exploitation (i.e., speed, ownership, and investments). While depletion is spread in a balanced Hotelling fashion during peace, the presence of conflict creates incentives for rapacious extraction, as this lowers the stakes of future contest. This voracious extraction depresses total oil revenue, especially if world oil demand is relatively elastic and the government's weapon advantage is weak. Some of these political distortions can be overcome by bribing rebels or by government investment in weapons. The shadow of conflict can also make less efficient nationalized oil extraction more attractive than private extraction, as insecure property rights create a holdup problem for the private firm and lead to a lower license fee. Furthermore, the government fights less intensely than the rebels under private exploitation, which leads to more government turnover. Without credible commitment to future fighting efforts, private oil depletion is only lucrative if the government's non-oil office rents are large and weaponry powerful, which guarantees the government a stronger grip on office and makes the holdup problem less severe.

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La Biblioteca de la UOC (UOC Library) ha ofert durant tres mesos (octubre-desembre 09), en fase de prova pilot, un servei de consulta i préstec de lectors de llibres electrònics (e-readers). Aquest nou desplegament s'ha desenvolupat en consonància amb l'aposta general de la Universitat en innovació en tecnologies aplicades a l'educació, i la voluntat de potenciar les col·leccions de llibres electrònics i l'ús dels dispositius de lectura de llibres electrònics com una extensió més de la tecnologia del Campus 5.0, en el suport a l'aprenentatge dels seus estudiants durant la seva formació a la Universitat. Aquest treball presenta en detall les especificacions de la prova pilot, a més de contenir una anàlisi i avaluació dels resultats obtinguts: punts forts i punts febles, relació dels aspectes a millorar i modificar, de cara a la consolidació final del servei.

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The current treatment of ocular toxoplasmosis is controversial. The mainstay of treatment has been pyrimethamine and sulphonamides with or without systemic corticosteroids, but the actual evidence that antibiotics have a beneficial effect in recurrent toxoplasmic retinochoroiditis is unsupported by randomised placebo controlled trials. Thus far there have only been three studies looking at the efficacy of antibiotic treatment, all of which were methodologically weak and two of which were perfomed more than 30 years ago. All studies reported adverse effects from treatment. There is an urgent need for further randomised, double blind, placebo controlled studies for lesions in all parts of the retina and to test the efficacy of adjunctive corticosteroid treatment.

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One of the unresolved questions of modern physics is the nature of Dark Matter. Strong experimental evidences suggest that the presence of this elusive component in the energy budget of the Universe is quite significant, without, however, being able to provide conclusive information about its nature. The most plausible scenario is that of weakly interacting massive particles (WIMPs), that includes a large class of non-baryonic Dark Matter candidates with a mass typically between few tens of GeV and few TeVs, and a cross section of the order of weak interactions. Search for Dark Matter particles using very high energy gamma-ray Cherenkov telescopes is based on the model that WIMPs can self-annihilate, leading to production of detectable species, like photons. These photons are very energetic, and since unreflected by the Universe's magnetic fields, they can be traced straight to the source of their creation. The downside of the approach is a great amount of background radiation, coming from the conventional astrophysical objects, that usually hides clear signals of the Dark Matter particle interactions. That is why good choice of the observational candidates is the crucial factor in search for Dark Matter. With MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov Telescopes), a two-telescope ground-based system located in La Palma, Canary Islands, we choose objects like dwarf spheroidal satellite galaxies of the Milky Way and galaxy clusters for our search. Our idea is to increase chances for WIMPs detection by pointing to objects that are relatively close, with great amount of Dark Matter and with as-little-as-possible pollution from the stars. At the moment, several observation projects are ongoing and analyses are being performed.