887 resultados para Availability and efficiency
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Mangroves are under threat worldwide by deforestation, overexploitation and climate change. The availability and consumption rates of propagules influence mangrove recruitment and can play a major role in their viability and restoration potential. We assess the potential trophic competition between Goniopsis cruentata and Ucides cordatus, two dominant crab species in the New World, by experimentally comparing herbivory levels between forest stands with varying crab abundance. We hypothesize that herbivory rates (HR) of G. cruentata will be lower in mangroves where it coexists with U. cordatus than in mangroves where U. cordatus is absent. The removal of Rhizophora mangle propagules was very rapid, and HR were overall high and increased through time. However, HR did not differ significantly between mangroves with and without the potential trophic competitor U. cordatus. Our study did not support previous literature indications of food competition between these two crab species, which seem to have developed strategies for competition avoidance.
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O objetivo deste trabalho foi avaliar o cultivo em larga escala de Ankistrodesmus gracilis e Diaphanososma birgei em laboratório através do estudo da biologia das espécies, composição bioquímica e custo operacional de produção. A. gracilis apresentou um crescimento exponencial até o sexto dia, ao redor de 144 x 10(4) células mL-1. Logo em seguida, sofreu um brusco decréscimo apresentando 90 x 10(4) células mL-1 (oitavo dia). A partir do décimo primeiro dia, as células algais tenderam a crescer novamente, apresentando um máximo de 135 x 10(4) células mL-1 no 17º dia. No cultivo de D. birgei, foi observado o primeiro pico de crescimento no nono dia com 140 x 10² indivíduos L-1, aumentando novamente a partir do décimo segundo dia. A alga clorofícea A. gracilis e o zooplâncton D. birgei possuem aproximadamente 50 e 70% de proteína (PS), respectivamente, com teor de carboidrato acima de 5%. A eletricidade e mão de obra foram os itens mais dispendiosos e, de acordo com os dados obtidos, a temperatura, nutrientes, disponibilidade de luz e manejo do cultivo, foram fatores determinantes sobre a produtividade. Os resultados indicam que o meio NPK (20-5-20) pode ser utilizado diretamente como uma alternativa de cultivo em larga escala, considerando o baixo custo de produção, promovendo adequado crescimento e valor nutricional para A. gracilis e D. birgei.
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The technique of delineating Populus tremuloides (Michx.) clonal colonies based on morphology and phenology has been utilized in many studies and forestry applications since the 1950s. Recently, the availability and robustness of molecular markers has challenged the validity of such approaches for accurate clonal identification. However, genetically sampling an entire stand is largely impractical or impossible. For that reason, it is often necessary to delineate putative genet boundaries for a more selective approach when genetically analyzing a clonal population. Here I re-evaluated the usefulness of phenotypic delineation by: (1) genetically identifying clonal colonies using nuclear microsatellite markers, (2) assessing phenotypic inter- and intraclonal agreement, and (3) determining the accuracy of visible characters to correctly assign ramets to their respective genets. The long-term soil productivity study plot 28 was chosen for analysis and is located in the Ottawa National Forest, MI (46° 37'60.0" N, 89° 12'42.7" W). In total, 32 genets were identified from 181 stems using seven microsatellite markers. The average genet size was 5.5 ramets and six of the largest were selected for phenotypic analyses. Phenotypic analyses included budbreak timing, DBH, bark thickness, bark color or brightness, leaf senescence, leaf serrations, and leaf length ratio. All phenotypic characters, except for DBH, were useful for the analysis of inter- and intraclonal variation and phenotypic delineation. Generally, phenotypic expression was related to genotype with multiple response permutation procedure (MRPP) intraclonal distance values ranging from 0.148 and 0.427 and an observed MRPP delta value=0.221 when the expected delta=0.5. The phenotypic traits, though, overlapped significantly among some clones. When stems were assigned into phenotypic groups, six phenotypic groups were identified with each group containing a dominant genotype or clonal colony. All phenotypic groups contained stems from at least two clonal colonies and no clonal colony was entirely contained within one phenotypic group. These results demonstrate that phenotype varies with genotype and stand clonality can be determined using phenotypic characters, but phenotypic delineation is less precise. I therefore recommend that some genetic identification follow any phenotypic delineation. The amount of genetic identification required for clonal confirmation is likely to vary based on stand and environmental conditions. Further analysis, however, is needed to test these findings in other forest stands and populations.
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The study evaluated the effects of herbivory pressure, nutrient availability and potential propagule supply on recruitment and succession of coral reef macroalgal communities. Recruitment and succession tiles were placed in a nutrient-herbivory factorial experiment and macroalgal abundances were evaluated through time. Proportional abundances of macroalgal form-functional groups on recruitment and succession tiles were similar to field established communities within treatments, evidencing possible effects of adult macroalgae as propagule supply. Macroalgal abundance of recruitment tiles increased with nutrient loading and herbivory reduction combined whereas on succession tiles nutrient loading increased abundance of articulated-calcareous only when herbivores were excluded. Macroalgal field established communities were only affected by herbivory reduction.
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Introduction: Food availability and access are strongly affected by seasonality in Ethiopia. However, there are little data on seasonal variation in Infant and Young Child Feeding (IYCF) practices and malnutrition among 6-23 months old children in different agro-ecological zones of rural Ethiopia. Methods: Socio-demographic, anthropometry and IYCF indicators were assessed in post- and pre-harvest seasons among children aged 6–23 months of age randomly selected from rural villages of lowland and midland agro-ecological zones. Results: Child stunting and underweight increased from prevalence of 39.8% and 26.9% in post-harvest to 46.0% and 31.8% in pre-harvest seasons, respectively. The biggest increase in prevalence of stunting and underweight between post- and pre-harvest seasons was noted in the midland zone. Wasting decreased from 11.6% post-harvest to 8.5% pre-harvest, with the biggest decline recorded in the lowland zone. Minimum meal frequency, minimum acceptable diet and poor dietary diversity increased considerably in pre-harvest compared to post-harvest season in the lowland zone. Feeding practices and maternal age were predictors of wasting, while women’s dietary diversity and children age was predictor of child dietary diversity in both seasons. Conclusion: There is seasonal variation in malnutrition and IYCF practices among children 6-23 months of age with more pronounced effect in midland agro-ecological zone. A major contributing factor for child malnutrition may be poor feeding practices. Health information strategies focused on both IYCF practices and dietary diversity of mothers could be a sensible approach to reduce the burden of child malnutrition in rural Ethiopia.
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Fully articulated hand tracking promises to enable fundamentally new interactions with virtual and augmented worlds, but the limited accuracy and efficiency of current systems has prevented widespread adoption. Today's dominant paradigm uses machine learning for initialization and recovery followed by iterative model-fitting optimization to achieve a detailed pose fit. We follow this paradigm, but make several changes to the model-fitting, namely using: (1) a more discriminative objective function; (2) a smooth-surface model that provides gradients for non-linear optimization; and (3) joint optimization over both the model pose and the correspondences between observed data points and the model surface. While each of these changes may actually increase the cost per fitting iteration, we find a compensating decrease in the number of iterations. Further, the wide basin of convergence means that fewer starting points are needed for successful model fitting. Our system runs in real-time on CPU only, which frees up the commonly over-burdened GPU for experience designers. The hand tracker is efficient enough to run on low-power devices such as tablets. We can track up to several meters from the camera to provide a large working volume for interaction, even using the noisy data from current-generation depth cameras. Quantitative assessments on standard datasets show that the new approach exceeds the state of the art in accuracy. Qualitative results take the form of live recordings of a range of interactive experiences enabled by this new approach.
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Theoretical models of social learning predict that individuals can benefit from using strategies that specify when and whom to copy. Here the interaction of two social learning strategies, model age-based biased copying and copy when uncertain, was investigated. Uncertainty was created via a systematic manipulation of demonstration efficacy (completeness) and efficiency (causal relevance of some actions). The participants, 4- to 6-year-old children (N = 140), viewed both an adult model and a child model, each of whom used a different tool on a novel task. They did so in a complete condition, a near-complete condition, a partial demonstration condition, or a no-demonstration condition. Half of the demonstrations in each condition incorporated causally irrelevant actions by the models. Social transmission was assessed by first responses but also through children’s continued fidelity, the hallmark of social traditions. Results revealed a bias to copy the child model both on first response and in continued interactions. Demonstration efficacy and efficiency did not affect choice of model at first response but did influence solution exploration across trials, with demonstrations containing causally irrelevant actions decreasing exploration of alternative methods. These results imply that uncertain environments can result in canalized social learning from specific classes of mode
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The aim of this study was to establish guidelines for the optimization of biologic therapies for health professionals involved in the management of patients with RA, AS and PsA. Recommendations were established via consensus by a panel of experts in rheumatology and hospital pharmacy, based on analysis of available scientific evidence obtained from four systematic reviews and on the clinical experience of panellists. The Delphi method was used to evaluate these recommendations, both between panellists and among a wider group of rheumatologists. Previous concepts concerning better management of RA, AS and PsA were reviewed and, more specifically, guidelines for the optimization of biologic therapies used to treat these diseases were formulated. Recommendations were made with the aim of establishing a plan for when and how to taper biologic treatment in patients with these diseases. The recommendations established herein aim not only to provide advice on how to improve the risk:benefit ratio and efficiency of such treatments, but also to reduce variability in daily clinical practice in the use of biologic therapies for rheumatic diseases
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The fact that most of the large scale solar PV plants are built in arid and semi-arid areas where land availability and solar radiation is high, it is expected the performance of the PV plants in such locations will be affected significantly due to high cell temperature as well as due to soiling. Therefore, it is essential to study how the different PV module technologies will perform in such geographical locations to ensure a consistent and reliable power delivery over the lifetime of the PV power plants. As soiling is strongly dependent on the climatic conditions of a particular location a test station, consisted of about 24 PV modules and a well-equipped weather station, was built within the fences of Scatec’s 75 MW Kalkbult solar PV plant in South Africa. This study was performed to a better understand the effect of soiling by comparing the relative power generation by the cleaned modules to the un-cleaned modules. Such knowledge can enable more quantitative evaluations of the cleaning strategies that are going to be implemented in bigger solar PV power plants. The data collected and recorded from the test station has been analyzed at IFE, Norway using a MatLab script written for this thesis project. This thesis work has been done at IFE, Norway in collaboration with Stellenbosch University in South Africa and Scatec Solar a Norwegian independent power producer company. Generally for the polycrystalline modules it is found that the average temperature corrected efficiency during the period of the experiment has been 15.00±0.08 % and for the thin film-CdTe with ARC is 11.52% and for the thin film without ARC is about 11.13% with standard uncertainty of ±0.01 %. Besides, by comparing the initial relative average efficiency of the polycrystalline-Si modules when all the modules have been cleaned for the first time and the final relative efficiency; after the last cleaning schedule which is when all the reference modules E, F, G, and H have been cleaned for the last time it is found that poly3 performs 2 % and 3 % better than poly1 and poly16 respectively, poly13 performs 1 % better than poly15 as well as poly5 and poly12 performs 1 % and 2 % better than poly10 respectively. Besides, poly5 and poly12 performs a 9 % and 11 % better than poly7. Furthermore, there is no change in performance between poly6 and poly9 as well as poly4 and poly15. However, the increase in performance of poly3 to poly1, poly13 to poly15 as well as poly5 and poly12 to poly10 is insignificant. In addition, it is found that TF22 perform 7% better than the reference un-cleaned module TF24 and similarly; TF21 performs 7% higher than TF23. Furthermore, modules with ARC glass (TF17, TF18, TF19, and TF20) shows that cleaning the modules with only distilled water (TF19) or dry-cleaned after cleaned with distilled water(TF20) decreases the performance of the modules by 5 % and 4 % comparing to its respective reference uncleanedmodules TF17 and TF18 respectively.
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Nous avons utilisé la télédétection pour examiner comment l’abondance du caribou migrateur pouvait influencer la quantité de ressources alimentaires, et comment ces changements pouvaient affecter la dynamique de population et les patrons d’utilisation de l’espace des caribous. Nous avons évalué les relations entre le caribou et ses ressources alimentaires pour l’aire de mise bas et l’aire d’estivage du troupeau Rivière-George (TRG) du nord du Québec et du Labrador (Canada) entre 1991 et 2011. Nous avons modélisé les relations entre la productivité primaire et des variables climatiques, nous permettant d’isoler les effets d’autres facteurs, comme la pression de broutement des caribous. Nous avons trouvé une relation négative entre la densité de caribous et la productivité primaire à grande échelle, suggérant que la pression de broutement par les caribous pouvait réduire l’abondance des ressources alimentaires et contribuer à la dégradation de l’habitat. Une forte tendance au réchauffement durant la période d’étude, couplée avec un déclin de la taille de population du TRG, a cependant entrainé une productivité primaire plus élevée. Cette hausse de la productivité primaire pourrait représenter un rétablissement de la végétation suite à la réduction de la pression de broutement et/ou un effet du réchauffement climatique.
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The aim of this study was to compute a swimming performance confirmatory model based on biomechanical parameters. The sample included 100 young swimmers (overall: 12.3 ± 0.74 years; 49 boys: 12.5 ± 0.76 years; 51 girls: 12.2 ± 0.71 years; both genders in Tanner stages 1–2 by self-report) participating on a regular basis in regional and national-level events. The 100 m freestyle event was chosen as the performance indicator. Anthropometric (arm span), strength (throwing velocity), power output (power to overcome drag), kinematic (swimming velocity) and efficiency (propelling efficiency) parameters were measured and included in the model. The path-flow analysis procedure was used to design and compute the model. The anthropometric parameter (arm span) was excluded in the final model, increasing its goodness-of-fit. The final model included the throw velocity, power output, swimming velocity and propelling efficiency. All links were significant between the parameters included, but the throw velocity–power output. The final model was explained by 69% presenting a reasonable adjustment (model’s goodness-of-fit; x2/df = 3.89). This model shows that strength and power output parameters do play a mediator and meaningful role in the young swimmers’ performance.
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In 2014, Portugal was the seventh largest pellets producer in the World. Since the shortage of raw material is one of the major obstacles that the Portuguese sellets market faces, the need for a good assessment of biomass availability for energy purposes at both country and regional levels is reinforced. This work uses a Geographical Information System environment and remote sensing data to assess the availability and sustainability of forest biomass residues in a management unit with around 940 ha of maritime pine forest. The period considered goes from 2004 to 2015. The study area is located in Southwestern Portugal, close to a pellets factory; therefore the potential Contribution of the residual biomass generated in the management unit to the production of pellets is evaluated. An allometric function is used for the estimation of maritime pine above ground biomass. With this estimate, and considering several forest operations, the residual biomass available was assessed, according to stand composition and structure. This study shows that, when maritime pine forests are managed to produce wood, the amount of residues available for energy production is small (an average of 0.37 t ha -1 year -1 were generated in the study area between 2004 and 2015). As a contribution to the sustainability of the Portuguese pellets industries, new management models for maritime pine forests may be developed. The effect of the pinewood nematode on the availability of residual biomass can be clearly seen in this study. In the management unit considered, cuts were made to prevent dissemination of the disease. This contributes to a higher availability of forest residues in a specific period of time, but, in the medium term, they lead to a decrease in the amount of residues that can be used for energy purposes.
Design and Development of a Research Framework for Prototyping Control Tower Augmented Reality Tools
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The purpose of the air traffic management system is to ensure the safe and efficient flow of air traffic. Therefore, while augmenting efficiency, throughput and capacity in airport operations, attention has rightly been placed on doing it in a safe manner. In the control tower, many advances in operational safety have come in the form of visualization tools for tower controllers. However, there is a paradox in developing such systems to increase controllers' situational awareness: by creating additional computer displays, the controller's vision is pulled away from the outside view and the time spent looking down at the monitors is increased. This reduces their situational awareness by forcing them to mentally and physically switch between the head-down equipment and the outside view. This research is based on the idea that augmented reality may be able to address this issue. The augmented reality concept has become increasingly popular over the past decade and is being proficiently used in many fields, such as entertainment, cultural heritage, aviation, military & defense. This know-how could be transferred to air traffic control with a relatively low effort and substantial benefits for controllers’ situation awareness. Research on this topic is consistent with SESAR objectives of increasing air traffic controllers’ situation awareness and enable up to 10 % of additional flights at congested airports while still increasing safety and efficiency. During the Ph.D., a research framework for prototyping augmented reality tools was set up. This framework consists of methodological tools for designing the augmented reality overlays, as well as of hardware and software equipment to test them. Several overlays have been designed and implemented in a simulated tower environment, which is a virtual reconstruction of Bologna airport control tower. The positive impact of such tools was preliminary assessed by means of the proposed methodology.
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The increasing demand for alternatives to meat food products, which is linked to ethical and environmental reasons, highlights the necessity of using different protein sources. Plant proteins provide a valid option, thanks to the relative low costs, high availability and wide supply sources. The current process used to produce plant concentrates and isolates is the alkaline extraction followed by isoelectric precipitation. However, despite the high purity of the proteins, it presents some drawbacks. Innovative protein extraction processes are emerging, with the aim of reducing the environmental impact and the costs, as well as improving the functional properties. In this study, the traditional wet protein extraction and another simplified wet process were used to obtain protein-rich extracts out of different plants. The sources considered in the project were de-oiled sunflower and canola, chickpea, lentils, and the camelina meal, an emerging oleaginous seed interesting for its high content of omega 3. The extracts obtained from the two processes were then analysed for their capacities to hold water and fat, to form gel and a stable foam. Results highlighted strong differences concerning the protein content, yield and functionalities. The extracts obtained with the alkaline process confirmed the literature data about the four plant sources (sunflower, canola, chickpea and lentils) and allow to obtain a camelina concentrate with a protein content of 63 % and a protein recovery of 41 %. The second easiest process was not effective to obtain a protein enrichment in oleaginous sources, whereas an enrichment of 10 and 15 % was obtained in chickpea and lentils, respectively. The functional properties were also completely different: the easiest process produced protein ingredients completely water-soluble at pH 7, with a discrete foaming capacity compared to the extracts obtained with alkaline process. These characteristics could make these extracts suitable for the plant milk-analogue products.
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If we look back in time at the history of humanity, we can state that our generation is living an era of outstanding efficiency and progress because of globalization and global competition, even if this is resulting in the rapid depletion of energy sources and raw materials. The environmental impact of non-biodegradable plastic wastes is of increasing global concern: nowadays, imagining a world without synthetic plastics seems impossible, though their large-scale production and their extensive use have only spread since the end of the World War II. In recent years, the demand for sustainable materials has increased significantly and, with a view to circular economy, research has also focused on the enhancement and subsequent reuse of waste materials produced by industrial processing, intensive farming and the agricultural sector. Plastic polymers have been the most practical and economical solution for decades due to their low cost, prompt availability and excellent optical, mechanical and barrier properties. Biodegradable polymers could replace them in many applications, thus reducing the problems of traditional plastics disposability and the dependence on petroleum. Natural biopolymers are in fact characterized by a high biocompatibility and biodegradability and have already prompted research in the field of regenerative medicine. During my PhD, my goal was to use natural polymers from sustainable sources as raw materials to produce biomaterials, which are materials designed to interface with biological systems to evaluate, support or replace any tissue, organ, or function of the body. I focused on the use of the most abundant biopolymers in nature to produce biomaterials in the form of films, scaffolds and cements. After a complete characterization, the materials were proposed for suitable applications in different fields, from tissue engineering to cosmetics and food packaging. Some of the obtained results were published on international scientific and peer-reviewed journals.