980 resultados para Use dynamics
Resumo:
Despite several clinical tests that have been developed to qualitatively describe complex motor tasks by functional testing, these methods often depend on clinicians' interpretation, experience and training, which make the assessment results inconsistent, without the precision required to objectively assess the effect of the rehabilitative intervention. A more detailed characterization is required to fully capture the various aspects of motor control and performance during complex movements of lower and upper limbs. The need for cost-effective and clinically applicable instrumented tests would enable quantitative assessment of performance on a subject-specific basis, overcoming the limitations due to the lack of objectiveness related to individual judgment, and possibly disclosing subtle alterations that are not clearly visible to the observer. Postural motion measurements at additional locations, such as lower and upper limbs and trunk, may be necessary in order to obtain information about the inter-segmental coordination during different functional tests involved in clinical practice. With these considerations in mind, this Thesis aims: i) to suggest a novel quantitative assessment tool for the kinematics and dynamics evaluation of a multi-link kinematic chain during several functional motor tasks (i.e. squat, sit-to-stand, postural sway), using one single-axis accelerometer per segment, ii) to present a novel quantitative technique for the upper limb joint kinematics estimation, considering a 3-link kinematic chain during the Fugl-Meyer Motor Assessment and using one inertial measurement unit per segment. The suggested methods could have several positive feedbacks from clinical practice. The use of objective biomechanical measurements, provided by inertial sensor-based technique, may help clinicians to: i) objectively track changes in motor ability, ii) provide timely feedback about the effectiveness of administered rehabilitation interventions, iii) enable intervention strategies to be modified or changed if found to be ineffective, and iv) speed up the experimental sessions when several subjects are asked to perform different functional tests.
Resumo:
The European renewable energy directive 2009/28/EC (E.C. 2009) provides a legislative framework for reducing GHG emissions by 20%, while achieving a 20% share of energy from renewable sources by 2020. Perennial energy crops could significantly contribute to limit GHG emissions through replacing equivalent fossil fuels and by sequestering a considerable amount of carbon into the soil through the large amounts of belowground biomass produced. The objective of this study is to evaluate the effects of land use change that perennial energy crops have on croplands (switchgrass) and marginal grasslands (miscanthus). For that purpose above and belowground biomass, SOC variation and Net Ecosystem Exchange were evaluated after five years of growth. At aboveground level both crops produced high biomass under cropland conditions as well as under marginal soils. At belowground level they also produced large amounts of biomass, but no significant influences on SOC in the upper layer (0-30 cm) were found. This is probably because of the "priming effect" that caused fast carbon substitution. In switchgrass only it was found a significant SOC increase in deeper layers (30-60 cm), while in the whole soil profile (0-60 cm) SOC increased from 42 to 51 ha-1. However, the short experimental periods (for both switchgrass and miscanthus), in which land use change was evaluated, do not permit to determine the real capacity of perennial energy crops to accumulate SOC. In conclusion the large amounts of belowground biomass enhanced the SOC dynamic through the priming effect resulting in increased SOC in cropland but not in marginal grassland.
Resumo:
The presented thesis revolves around the study of thermally-responsive PNIPAAm-based hydrogels in water/based environments, as studied by Fluorescence Correlation Spectroscopy (FCS).rnThe goal of the project was the engineering of PNIPAAm gels into biosensors. Specifically, a gamma of such gels were both investigated concerning their dynamics and structure at the nanometer scale, and their performance in retaining bound bodies upon thermal collapse (which PNIPAAm undergoes upon heating above 32 ºC).rnFCS’s requirements, as a technique, match the limitations imposed by the system. Namely, the need to intimately probe a system in a solvent, which was also fragile and easy to alter. FCS, on the other hand, both requires a fluid environment to work, and is based on the observation of diffusion of fluorescents at nanomolar concentrations. FCS was applied to probe the hydrogels on the nanometer size with minimal invasivity.rnVariables in the gels were addressed in the project including crosslinking degree; structural changes during thermal collapse; behavior in different buffers; the possibility of decreasing the degree of inhomogeneity; behavior of differently sized probes; and the effectiveness of antibody functionalization upon thermal collapse.rnThe evidenced results included the heightening of structural inhomogeneities during thermal collapse and under different buffer conditions; the use of annealing to decrease the inhomogeneity degree; the use of differently sized probes to address different length scale of the gel; and the successful functionalization before and after collapse.rnThe thesis also addresses two side projects, also carried forward via FCS. One, diffusion in inverse opals, produced a predictive simulation model for diffusion of bodies in confined systems as dependent on the bodies’ size versus the characteristic sizes of the system. The other was the observation of interaction of bodies of opposite charge in a water solution, resulting in a phenomenological theory and an evaluation method for both the average residence time of the different bodies together, and their attachment likelihood.
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An appropriate management of fisheries resources can only be achieved with the continuous supply of information on the structure and biology of populations, in order to predict the temporal fluctuations. This study supports the importance of investigating the bio-ecology of increasingly exploited and poorly known species, such as gurnards (Osteichthyes, Triglidae) from Adriatic Sea (Mediterranean), to quantify their ecological role into marine community. It also focuses on investigate inter and intra-specific structuring factor of Adriatic population. These objectives were achieved by: 1) investigating aspects of the population dynamics; 2) studying the feeding biology through the examination of stomach contents; 3) using sagittal otoliths as potential marker of species life cycle; 4) getting preliminary data on mDNA phylogeny. Gurnards showed a specie-specific “critical size” coinciding with the start of sexual maturity, the tendency to migrate to greater depths, a change of diet from crustaceans to fish and an increase of variety of food items eaten. Distribution of prey items, predator size range and depth distribution were the main dimensions that influence the breadth of trophic niche and the relative difference amongst Adriatic gurnards. Several feeding preferences were individuated and a possible impact among bigger-size gurnards and other commercial fishes (anchovy, gadoids) and Crustacea (such as mantis prawn and shrimps) were to be necessary considered. Otolith studies showed that gurnard species have a very fast growth despite other results in other areas; intra-specific differences and the increase in the variability of otolith shape, sulcus acusticus shape, S:O ratios, sulcus acusticus external crystals arrangement were shown between juveniles and adults and were linked to growth (individual genetic factors) and to environmental conditions (e.g. depth and trophic niche distribution). In order to facilitate correct biological interpretation of data, molecular data were obtained for comparing morphological distance to genetic ones.
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To assess the impact of screening programmes in reducing the prevalence of Chlamydia trachomatis, mathematical and computational models are used as a guideline for decision support. Unfortunately, large uncertainties exist about the parameters that determine the transmission dynamics of C. trachomatis. Here, we use a SEIRS (susceptible-exposed-infected-recovered-susceptible) model to critically analyze the turnover of C. trachomatis in a population and the impact of a screening programme. We perform a sensitivity analysis on the most important steps during an infection with C. trachomatis. Varying the fraction of the infections becoming symptomatic as well as the duration of the symptomatic period within the range of previously used parameter estimates has little effect on the transmission dynamics. However, uncertainties in the duration of temporary immunity and the asymptomatic period can result in large differences in the predicted impact of a screening programme. We therefore analyze previously published data on the persistence of asymptomatic C. trachomatis infection in women and estimate the mean duration of the asymptomatic period to be longer than anticipated so far, namely 433 days (95% CI: 420-447 days). Our study shows that a longer duration of the asymptomatic period results in a more pronounced impact of a screening programme. However, due to the slower turnover of the infection, a substantial reduction in prevalence can only be achieved after screening for several years or decades.
Resumo:
Access and accessibility are important determinants of people’s ability to utilise natural resources, and have a strong impact on household welfare. Physical accessibility of natural resources, on the other hand, has generally been regarded as one of the most important drivers of land-use and land-cover changes. Based on two case studies, this article discusses evidence of the impact of access to services and access to natural resources on household poverty and on the environment. We show that socio-cultural distances are a key limiting factor for gaining access to services, and thereby for improved household welfare. We also discuss the impact of socio-cultural distances on access to natural resources, and show that large-scale commercial exploitation of natural resources tends to occur beyond the spatial reach of socio-culturally and economically marginalised population segments. We conclude that it is essential to pay more attention to improving the structural environment that presently leaves social minority groups marginalised. Innovative approaches that use natural resource management to induce poverty reduction – for example, through compensation of local farmers for environmental services – appear to be promising avenues that can lead to integration of the objectives of poverty reduction and sustainable environmental stewardship.
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The goals of this article are to (1) provide further validation of the Glycam06 force field, specifically for its use in implicit solvent molecular dynamic (MD) simulations, and (2) to present the extension of G.N. Ramachandran's idea of plotting amino acid phi and psi angles to the glycosidic phi, psi, and omega angles formed between carbohydrates. As in traditional Ramachandran plots, these carbohydrate Ramachandran-type (carb-Rama) plots reveal the coupling between the glycosidic angles by displaying the allowed and disallowed conformational space. Considering two-bond glycosidic linkages, there are 18 possible conformational regions that can be defined by (α, ϕ, ψ) and (β, ϕ, ψ), whereas for three-bond linkages, there are 54 possible regions that can be defined by (α, ϕ, ψ, ω) and (β, ϕ, ψ, ω). Illustrating these ideas are molecular dynamic simulations on an implicitly hydrated oligosaccharide (700 ns) and its eight constituent disaccharides (50 ns/disaccharide). For each linkage, we compare and contrast the oligosaccharide and respective disaccharide carb-Rama plots, validate the simulations and the Glycam06 force field through comparison to experimental data, and discuss the general trends observed in the plots.
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We use long instrumental temperature series together with available field reconstructions of sea-level pressure (SLP) and three-dimensional climate model simulations to analyze relations between temperature anomalies and atmospheric circulation patterns over much of Europe and the Mediterranean for the late winter/early spring (January–April, JFMA) season. A Canonical Correlation Analysis (CCA) investigates interannual to interdecadal covariability between a new gridded SLP field reconstruction and seven long instrumental temperature series covering the past 250 years. We then present and discuss prominent atmospheric circulation patterns related to anomalous warm and cold JFMA conditions within different European areas spanning the period 1760–2007. Next, using a data assimilation technique, we link gridded SLP data with a climate model (EC-Bilt-Clio) for a better dynamical understanding of the relationship between large scale circulation and European climate. We thus present an alternative approach to reconstruct climate for the pre-instrumental period based on the assimilated model simulations. Furthermore, we present an independent method to extend the dynamic circulation analysis for anomalously cold European JFMA conditions back to the sixteenth century. To this end, we use documentary records that are spatially representative for the long instrumental records and derive, through modern analogs, large-scale SLP, surface temperature and precipitation fields. The skill of the analog method is tested in the virtual world of two three-dimensional climate simulations (ECHO-G and HadCM3). This endeavor offers new possibilities to both constrain climate model into a reconstruction mode (through the assimilation approach) and to better asses documentary data in a quantitative way.
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The vascular-stromal compartment of lymph nodes is important for lymph node function, and high endothelial venules (HEVs) play a critical role in controlling the entry of recirculating lymphocytes. In autoimmune and autoinflammatory diseases, lymph node swelling is often accompanied by apparent HEV expansion and, potentially, targeting HEV expansion could be used therapeutically to limit autoimmunity. In previous studies using mostly flow cytometry analysis, we defined three differentially regulated phases of lymph node vascular-stromal growth: initiation, expansion, and the re-establishment of vascular quiescence and stabilization. In this study, we use optical projection tomography to better understand the morphologic aspects of HEV growth upon immunization with ovalbumin/CFA (OVA/CFA). We find HEV elongation as well as modest arborization during the initiation phase, increased arborization during the expansion phase, and, finally, vessel narrowing during the re-establishment of vascular quiescence and stabilization. We also examine acutely enlarged autoinflammatory lymph nodes induced by regulatory T cell depletion and show that HEVs are expanded and morphologically similar to the expanded HEVs in OVA/CFA-stimulated lymph nodes. These results reinforce the idea of differentially regulated, distinct phases of vascular-stromal growth after immunization and suggest that insights gained from studying immunization-induced lymph node vascular growth may help to understand how the lymph node vascular-stromal compartment could be therapeutically targeted in autoimmune and autoinflammatory diseases.
Resumo:
Through studying German, Polish and Czech publications on Silesia, Mr. Kamusella found that most of them, instead of trying to objectively analyse the past, are devoted to proving some essential "Germanness", "Polishness" or "Czechness" of this region. He believes that the terminology and thought-patterns of nationalist ideology are so deeply entrenched in the minds of researchers that they do not consider themselves nationalist. However, he notes that, due to the spread of the results of the latest studies on ethnicity/nationalism (by Gellner, Hobsbawm, Smith, Erikson Buillig, amongst others), German publications on Silesia have become quite objective since the 1980s, and the same process (impeded by under funding) has been taking place in Poland and the Czech Republic since 1989. His own research totals some 500 pages, in English, presented on disc. So what are the traps into which historians have been inclined to fall? There is a tendency for them to treat Silesia as an entity which has existed forever, though Mr. Kamusella points out that it emerged as a region only at the beginning of the 11th century. These same historians speak of Poles, Czechs and Germans in Silesia, though Mr. Kamusella found that before the mid-19th century, identification was with an inhabitant's local area, religion or dynasty. In fact, a German national identity started to be forged in Prussian Silesia only during the Liberation War against Napoleon (1813-1815). It was concretised in 1861 in the form of the first Prussian census, when the language a citizen spoke was equated with his/her nationality. A similar census was carried out in Austrian Silesia only in 1881. The censuses forced the Silesians to choose their nationality despite their multiethnic multicultural identities. It was the active promotion of a German identity in Prussian Silesia, and Vienna's uneasy acceptance of the national identities in Austrian Silesia which stimulated the development of Polish national, Moravian ethnic and Upper Silesian ethnic regional identities in Upper Silesia, and Polish national, Czech national, Moravian ethnic and Silesian ethnic identities in Austrian Silesia. While traditional historians speak of the "nationalist struggle" as though it were a permanent characteristic of Silesia, Mr. Kamusella points out that such a struggle only developed in earnest after 1918. What is more, he shows how it has been conveniently forgotten that, besides the national players, there were also significant ethnic movements of Moravians, Upper Silesians, Silesians and the tutejsi (i.e. those who still chose to identify with their locality). At this point Mr. Kamusella moves into the area of linguistics. While traditionally historians have spoken of the conflicts between the three national languages (German, Polish and Czech), Mr Kamusella reminds us that the standardised forms of these languages, which we choose to dub "national", were developed only in the mid-18th century, after 1869 (when Polish became the official language in Galicia), and after the 1870s (when Czech became the official language in Bohemia). As for standard German, it was only widely promoted in Silesia from the mid 19th century onwards. In fact, the majority of the population of Prussian Upper Silesia and Austrian Silesia were bi- or even multilingual. What is more, the "Polish" and "Czech" Silesians spoke were not the standard languages we know today, but a continuum of West-Slavic dialects in the countryside and a continuum of West-Slavic/German creoles in the urbanised areas. Such was the linguistic confusion that, from time to time, some ethnic/regional and Church activists strove to create a distinctive Upper Silesian/Silesian language on the basis of these dialects/creoles, but their efforts were thwarted by the staunch promotion of standard German, and after 1918, of standard Polish and Czech. Still on the subject of language, Mr. Kamusella draws attention to a problem around the issue of place names and personal names. Polish historians use current Polish versions of the Silesian place names, Czechs use current Polish/Czech versions of the place names, and Germans use the German versions which were in use in Silesia up to 1945. Mr. Kamusella attempted to avoid this, as he sees it, nationalist tendency, by using an appropriate version of a place name for a given period and providing its modern counterpart in parentheses. In the case of modern place names he gives the German version in parentheses. As for the name of historical figures, he strove to use the name entered on the birth certificate of the person involved, and by doing so avoid such confusion as, for instance, surrounds the Austrian Silesian pastor L.J. Sherschnik, who in German became Scherschnick, in Polish, Szersznik, and in Czech, Sersnik. Indeed, the prospective Silesian scholar should, Mr. Kamusella suggests, as well as the three languages directly involved in the area itself, know English and French, since many documents and books on the subject have been published in these languages, and even Latin, when dealing in depth with the period before the mid-19th century. Mr. Kamusella divides the policies of ethnic cleansing into two categories. The first he classifies as soft, meaning that policy is confined to the educational system, army, civil service and the church, and the aim is that everyone learn the language of the dominant group. The second is the group of hard policies, which amount to what is popularly labelled as ethnic cleansing. This category of policy aims at the total assimilation and/or physical liquidation of the non-dominant groups non-congruent with the ideal of homogeneity of a given nation-state. Mr. Kamusella found that soft policies were consciously and systematically employed by Prussia/Germany in Prussian Silesia from the 1860s to 1918, whereas in Austrian Silesia, Vienna quite inconsistently dabbled in them from the 1880s to 1917. In the inter-war period, the emergence of the nation-states of Poland and Czechoslovakia led to full employment of the soft policies and partial employment of the hard ones (curbed by the League of Nations minorities protection system) in Czechoslovakian Silesia, German Upper Silesia and the Polish parts of Upper and Austrian Silesia. In 1939-1945, Berlin started consistently using all the "hard" methods to homogenise Polish and Czechoslovakian Silesia which fell, in their entirety, within the Reich's borders. After World War II Czechoslovakia regained its prewar part of Silesia while Poland was given its prewar section plus almost the whole of the prewar German province. Subsequently, with the active involvement and support of the Soviet Union, Warsaw and Prague expelled the majority of Germans from Silesia in 1945-1948 (there were also instances of the Poles expelling Upper Silesian Czechs/Moravians, and of the Czechs expelling Czech Silesian Poles/pro-Polish Silesians). During the period of communist rule, the same two countries carried out a thorough Polonisation and Czechisation of Silesia, submerging this region into a new, non-historically based administrative division. Democratisation in the wake of the fall of communism, and a gradual retreat from the nationalist ideal of the homogeneous nation-state with a view to possible membership of the European Union, caused the abolition of the "hard" policies and phasing out of the "soft" ones. Consequently, limited revivals of various ethnic/national minorities have been observed in Czech and Polish Silesia, whereas Silesian regionalism has become popular in the westernmost part of Silesia which remained part of Germany. Mr. Kamusella believes it is possible that, with the overcoming of the nation-state discourse in European politics, when the expression of multiethnicity and multilingualism has become the cause of the day in Silesia, regionalism will hold sway in this region, uniting its ethnically/nationally variegated population in accordance with the principle of subsidiarity championed by the European Union.
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The rotational nature of shifting cultivation poses several challenges to its detection by remote sensing. Consequently, there is a lack of spatial data on the dynamics of shifting cultivation landscapes on a regional, i.e. sub-national, or national level. We present an approach based on a time series of Landsat and MODIS data and landscape metrics to delineate the dynamics of shifting cultivation landscapes. Our results reveal that shifting cultivation is a land use system still widely and dynamically utilized in northern Laos. While there is an overall reduction in the areas dominated by shifting cultivation, some regions also show an expansion. A review of relevant reports and articles indicates that policies tend to lead to a reduction while market forces can result in both expansion and reduction. For a better understanding of the different factors affecting shifting cultivation landscapes in Laos, further research should focus on spatially explicit analyses.
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No data about the use of the pentasaccharide fondaparinux, a highly selective indirect inhibitor of factor Xa, in patients treated with haemodialysis are available. Therefore, we investigated the pharmacokinetics and -dynamics of fondaparinux in 12 patients during haemodialysis. The anti-Xa activity (expressed as fondaparinux equivalent) was monitored, a semiquantitative clotting scale (SQCS) ranging from 0 (no visible traces of coagula) to 3 (complete clotting of the dialysis circuit) was applied, and the digital compression time necessary to achieve haemostasis at the puncture site was determined. After an initial period, when the regular heparin dose was replaced once weekly by fondaparinux, 0.05 mg/kg, the pentasaccharide was administered for nine consecutive haemodialysis sessions. Peak anti-Xa activity increased from 0.61 +/- 0.14 microg/l after the first dose to 0.89 +/- 0.24 microg/l after dose 9 (P < 0.001), whereas predialysis anti-Xa activity steadily rose to 0.32 +/- 0.09 microg/l (P < 0.001). A sufficient but slightly less effective anticoagulation with a mean SQCS of 1.19 +/- 0.71 (n = 121) was obtained by fondaparinux as compared with 0.65 +/- 0.58 (n = 60, P < 0.005) by 4,825 +/- 1,703 U of unfractionated heparin. Mean digital compression time rose slightly during fondaparinux from 23.7 +/- 7.4 minutes to 24.8 +/- 7.5 minutes (P < 0.05) and, more important, six of the 12 patients reported minor bleeding problems during the interdialytic interval. Thus, fondaparinux can be used to prevent circuit clotting during haemodialysis; however, accumulation results in an interdialytic increase of anti-Xa activity. Therefore, fondaparinux should be reserved for patients requiring systemic anticoagulation on the days off dialysis.
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Models of population dynamics generally neglect the presence of males. While this assumption holds under many circumstances, behavioural ecology increasingly tells us that the presence (or absence) of males may have an impact on female fitness, and hence population sizes. Here we ask the question of whether males matter to population dynamics, operationally defined as a dependency of population growth on the relative density of males. We provide simple models, and evaluate the current empirical evidence for them, that illustrate various mechanisms of such male influence: mate searching behavior, male resource use (including effects of sexual dimorphism), sexual harassment and sexual segregation. In each case, theory predicts that males can have an effect on population densities, and in some extreme cases a positive feedback between an increasingly male-biased sex ratio and the effects on female harassment may theoretically even bring about population extinction. The results of this study, and the literature reviewed, show that the males can have a substantial effect on population dynamics, particularly so when human influences result in biased sex ratios.
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Reducing the uncertainties related to blade dynamics by the improvement of the quality of numerical simulations of the fluid structure interaction process is a key for a breakthrough in wind-turbine technology. A fundamental step in that direction is the implementation of aeroelastic models capable of capturing the complex features of innovative prototype blades, so they can be tested at realistic full-scale conditions with a reasonable computational cost. We make use of a code based on a combination of two advanced numerical models implemented in a parallel HPC supercomputer platform: First, a model of the structural response of heterogeneous composite blades, based on a variation of the dimensional reduction technique proposed by Hodges and Yu. This technique has the capacity of reducing the geometrical complexity of the blade section into a stiffness matrix for an equivalent beam. The reduced 1-D strain energy is equivalent to the actual 3-D strain energy in an asymptotic sense, allowing accurate modeling of the blade structure as a 1-D finite-element problem. This substantially reduces the computational effort required to model the structural dynamics at each time step. Second, a novel aerodynamic model based on an advanced implementation of the BEM(Blade ElementMomentum) Theory; where all velocities and forces are re-projected through orthogonal matrices into the instantaneous deformed configuration to fully include the effects of large displacements and rotation of the airfoil sections into the computation of aerodynamic forces. This allows the aerodynamic model to take into account the effects of the complex flexo-torsional deformation that can be captured by the more sophisticated structural model mentioned above. In this thesis we have successfully developed a powerful computational tool for the aeroelastic analysis of wind-turbine blades. Due to the particular features mentioned above in terms of a full representation of the combined modes of deformation of the blade as a complex structural part and their effects on the aerodynamic loads, it constitutes a substantial advancement ahead the state-of-the-art aeroelastic models currently available, like the FAST-Aerodyn suite. In this thesis, we also include the results of several experiments on the NREL-5MW blade, which is widely accepted today as a benchmark blade, together with some modifications intended to explore the capacities of the new code in terms of capturing features on blade-dynamic behavior, which are normally overlooked by the existing aeroelastic models.