925 resultados para Wave-function Approach
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The analysis of rockfall characteristics and spatial distribution is fundamental to understand and model the main factors that predispose to failure. In our study we analysed LiDAR point clouds aiming to: (1) detect and characterise single rockfalls; (2) investigate their spatial distribution. To this end, different cluster algorithms were applied: 1a) Nearest Neighbour Clutter Removal (NNCR) in combination with the Expectation?Maximization (EM) in order to separate feature points from clutter; 1b) a density based algorithm (DBSCAN) was applied to isolate the single clusters (i.e. the rockfall events); 2) finally we computed the Ripley's K-function to investigate the global spatial pattern of the extracted rockfalls. The method allowed proper identification and characterization of more than 600 rockfalls occurred on a cliff located in Puigcercos (Catalonia, Spain) during a time span of six months. The spatial distribution of these events proved that rockfall were clustered distributed at a welldefined distance-range. Computations were carried out using R free software for statistical computing and graphics. The understanding of the spatial distribution of precursory rockfalls may shed light on the forecasting of future failures.
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Numerous health benefits have been attributed to cocoa and its derived products in the last decade including antioxidant, anti-platelet and positive effects on lipid metabolism and vascular function. Inflammation plays a key role in the initiation and progression of atherosclerosis. However, cocoa feeding trials focused on inflammation are still rare and the results yielded are controversial. Health effects derived from cocoa consumption have been partly attributed to its polyphenol content, in particular of flavanols. Bioavailability is a key issue for cocoa polyphenols in order to be able to exert their biological activities. In the case of flavanols, bioavailability is strongly influenced by several factors, such as their degree of polymerization and the food matrix in which the polyphenols are delivered. Furthermore, gut has become an active site for the metabolism of procyanidins (oligomeric and polymeric flavanols). Estimation of polyphenol consumption or exposure is also a very challenging task in Food and Nutrition Science in order to correlate the intake of phytochemicals with in vivo health effects. In the area of nutrition, modern analytical techniques based on mass spectrometry are leading to considerable advances in targeted metabolite analysis and particularly in Metabolomics or global metabolite analysis. In this chapter we have summarized the most relevant results of our recent research on the bioavailability of cocoa polyphenols in humans and the effect of the matrix in which cocoa polyphenols are delivered considering both targeted analysis and a metabolomic approach. Furthermore, we have also summarized the effect of long-term consumption of cocoa powder in patients at high risk of cardiovascular disease (CVD) on the inflammatory biomarkers of atherosclerosis.
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International relations professionals need cross-cultural competence and English language communication skills to function in the international arena (Graddol 1997). English language communication skills are necessary not only to communicate with foreign colleagues (Bocanegra-Valle 2014) but also to access the vast amount of knowledge transmitted in English over the internet (Ku, Zussman 2010). This work reports the use of CLIL and cross-cultural training in the University of Messina International Relations Advanced Degree Program as a method to raise students’ level of English as quickly as possible while giving them the essential intercultural skills for work in the international field. The researchbased course program combined cross-cultural communication training (Storti, 1997; Lewis, 1999; Gannon, 2004, Harris and Moran, 2007; U.S Peace Corps Training Handbook 2012,) and intercultural competence skill development (Bennett, 1998). Two objectives were proposed: 1) develop cross-cultural communication competence; 2) bring students up to a B2 level as fast as possible. The final exam demonstrated significant growth in the areas of cross-cultural competence as well as an increase in European Common Framework level ranging from .5 to 1.0 depending on the student. Students expressed their belief that what they had learned would be useful for their future career. Combining CLIL with intercultural competence building seems to be effective in meeting two objectives: increasing English language fluency and developing cross-cultural communication competence. More research is recommended to further document this method for increasing English communication proficiency while developing interculturally competent international professionals.
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Dreaming is a pure form of phenomenality, created by the brain untouched by external stimulation or behavioral activity, yet including a full range of phenomenal contents. Thus, it has been suggested that the dreaming brain could be used as a model system in a biological research program on consciousness (Revonsuo, 2006). In the present thesis, the philosophical view of biological realism is accepted, and thus, dreaming is considered as a natural biological phenomenon, explainable in naturalistic terms. The major theoretical contribution of the present thesis is that it explores dreaming from a multidisciplinary perspective, integrating information from various fields of science, such as dream research, consciousness research, evolutionary psychology, and cognitive neuroscience. Further, it places dreaming into a multilevel framework, and investigates the constitutive, etiological, and contextual explanations for dreaming. Currently, the only theory offering a full multilevel explanation for dreaming, that is, a theory including constitutive, etiological, and contextual level explanations, is the Threat Simulation Theory (TST) (Revonsuo, 2000a; 2000b). The empirical significance of the present thesis lies in the tests conducted to test this specific theory put forth to explain the form, content, and biological function of dreaming. The first step in the empirical testing of the TST was to define exact criteria for what is a ‘threatening event’ in dreams, and then to develop a detailed and reliable content analysis scale with which it is possible to empirically explore and quantify threatening events in dreams. The second step was to seek answers to the following questions derived from the TST: How frequent threatening events are in dreams? What kind of qualities these events have? How threatening events in dreams relate to the most recently encoded or the most salient memory traces of threatening events experienced in waking life? What are the effects of exposure to severe waking life threat on dreams? The results reveal that threatening events are relatively frequent in dreams, and that the simulated threats are realistic. The most common threats include aggression, are targeted mainly against the dream self, and include simulations of relevant and appropriate defensive actions. Further, real threat experiences activate the threat simulation system in a unique manner, and dream content is modulated by the activation of long term episodic memory traces with highest negative saliency. To sum up, most of the predictions of the TST tested in this thesis received considerable support. The TST presents a strong argument that explains the specific design of dreams as threat simulations. The TST also offers a plausible explanation for why dreaming would have been selected for: because dreaming interacted with the environment in such a way that enhanced fitness of ancestral humans. By referring to a single threat simulation mechanism it furthermore manages to explain a wide variety of dream content data that already exists in the literature, and to predict the overall statistical patterns of threat content in different samples of dreams. The TST and the empirical tests conducted to test the theory are a prime example of what a multidisciplinary approach to mental phenomena can accomplish. Thus far, dreaming seems to have always resided in the periphery of science, never regarded worth to be studied by the mainstream. Nevertheless, when brought to the spotlight, the study of dreaming can greatly benefit from ideas in diverse branches of science. Vice versa, knowledge learned from the study of dreaming can be applied in various disciplines. The main contribution of the present thesis lies in putting dreaming back where it belongs, that is, into the spotlight in the cross-road of various disciplines.
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An analytical approximation, depending on five parameters, for the atomic screening function is proposed. The corresponding electrostatic potential takes a simple analytical form (superposition of three Yukawa potentials) well suited to most practical applications. Parameters in the screening function, determined by an analytical fitting procedure to Dirac-Hartree-Fock-Slater (DHFS) self-consistent data, are given for Z=1¿92. The reliability of this analytical approach is demonstrated by showing that (a) Born cross sections for elastic scattering of fast charged particles by the present analytical field and by the DHFS field practically coincide and (b) one-electron binding energies computed from the independent-particle model with our analytical field (corrected for exchange and electrostatic self-interaction) agree closely with the DHFS energy eigenvalues.
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This article examines the effect on price of different characteristics of holiday hotels in the sun-and-beach segment. The effect on price is estimated under the hedonic function perspective by means of random effect models, known also as mixed or panel models. Some 82,000 prices were gathered between 1991 and 1998 from tour operator catalogues. The study reveals huge price differences between 4-star hotels and the rest, coupled with practically no difference between 1-star and 2-star hotels. Other attributes with a significant effect on price are town, hotel size, distance to the beach and availability of parking place. The results can assist hotel managers in shaping pricing and investment strategies
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Logistics management is increasingly being recognised by many companies to be of critical concern. The logistics function includes directly or indirectly many of the new areas for achieving or maintaining competitive advantage that companies have been forced to develop due to increasing competitive pressures. The key to achieving a competitive advantage is to manage the logistics function strategically which involves determining the most cost effective method of providing the necessary customer service levels from the many combinations of operating procedures in the areas of transportation, warehousing, order processing and information systems, production, and inventory management. In this thesis, a comprehensive distribution logistics strategic management process is formed by integrating the periodic strategic planning process with a continuous strategic issues management process. Strategic planning is used for defining the basic objectives for a company and assuring co operation and synergy between the different functions of a company while strategic issues management is used on a continuous basis in order to deal with environmental and internal turbulence. The strategic planning subprocess consists of the following main phases: (1) situational analyses, (2) defining the vision and strategic goals for the logistics function, (3) determining objectives and strategies, (4) drawing up tactical action plans, and (5) evaluating the implementation of the plans and making the needed adjustments. The aim of the strategic issues management subprocess is to continuously scan the environment and the organisation for early identification of the issues having a significant impact on the logistics function using the following steps: (1) the identification of trends, (2) assessing the impact and urgency of the identified trends, (3) assigning priorities to the issues, and (4) planning responses to the, issues. The Analytic Hierarchy Process (AHP) is a systematic procedure for structuring any problem. AHP is based on the following three principles: decomposition, comparative judgements, and synthesis of priorities. AHP starts by decomposing a complex, multicriteria problem into a hierarchy where each level consists of a few manageable elements which are then decomposed into another set of elements. The second step is to use a measurement methodology to establish priorities among the elements within each level of the hierarchy. The third step in using AHP is to synthesise the priorities of the elements to establish the overall priorities for the decision alternatives. In this thesis, decision support systems are developed for different areas of distribution logistics strategic management by applying the Analytic Hierarchy Process. The areas covered are: (1) logistics strategic issues management, (2) planning of logistic structure, (3) warehouse site selection, (4) inventory forecasting, (5) defining logistic action and development plans, (6) choosing a distribution logistics strategy, (7) analysing and selecting transport service providers, (8) defining the logistic vision and strategic goals, (9) benchmarking logistic performance, and (10) logistic service management. The thesis demonstrates the potential of AHP as a systematic and analytic approach to distribution logistics strategic management.
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Across Latin America 420 indigenous languages are spoken. Spanish is considered a second language in indigenous communities and is progressively introduced in education. However, most of the tools to support teaching processes of a second language have been developed for the most common languages such as English, French, German, Italian, etc. As a result, only a small amount of learning objects and authoring tools have been developed for indigenous people considering the specific needs of their population. This paper introduces Multilingual–Tiny as a web authoring tool to support the virtual experience of indigenous students and teachers when they are creating learning objects in indigenous languages or in Spanish language, in particular, when they have to deal with the grammatical structures of Spanish. Multilingual–Tiny has a module based on the Case-based Reasoning technique to provide recommendations in real time when teachers and students write texts in Spanish. An experiment was performed in order to compare some local similarity functions to retrieve cases from the case library taking into account the grammatical structures. As a result we found the similarity function with the best performance
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Atherosclerotic vascular disease is the leading cause of death in the Western world. Its main three manifestations are coronary heart disease, cerebrovascular disease, and peripheral arterial disease. Asymptomatic peripheral arterial disease is usually diagnosed using the ankle brachial index, and values ≤ 0.90 are used to determine the diagnosis. The classical risk factors of peripheral arterial disease, such as smoking and diabetes, are well known and early interventions are mandatory to improve the prognosis. What is not well known is the role of inflammation as a risk factor. Yet, a novel approach to cardiovascular diseases is the measurement of endothelial function. In this thesis, we studied the ankle-brachial index, C-reactive protein and endothelial function in a cardiovascular risk population. A total of 2856 subjects were invited to the study and 2085 (73%) responded. From these subjects, a cohort of 1756 risk persons was screened. We excluded the subjects with previously known cardiovascular disease or diabetes, because they were already under systematic follow-up. Out of the study subjects, 983 (56%) were women and 773 (44%) men. The ankle brachial index and high-sensitivity C-reactive protein were measured from 1047 subjects. Endothelial function was assessed by measuring reactive hyperemia pulse amplitude tonometry from 66 subjects with borderline peripheral arterial disease. In this study, smoking was a crucial risk factor for peripheral arterial disease. Subclinical peripheral arterial disease seems to be more common in hypertensive patients even without comorbidities. The measurement of the ankle brachial index is an efficient method to identify patients at an increased cardiovascular risk. High-sensitivity C-reactive protein did not correlate with the ankle brachial index or peripheral arterial disease. Instead, it correlated with measures of obesity. In a cardiovascular risk population with borderline peripheral arterial disease, nearly every fourth subject had endothelial dysfunction. This might point out a subgroup of individuals in need of more intensive treatment for their risk factors.
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The objective of this work was to optimize the parameter setup for GTAW of aluminum using an AC rectangular wave output and continuous feeding. A series of welds was carried-out in an industrial joint, with variation of the negative and positive current amplitude, the negative and positive duration time, the travel speed and the feeding speed. Another series was carried out to investigate the isolate effect of the negative duration time and travel speed. Bead geometry aspects were assessed, such as reinforcement, penetration, incomplete fusion and joint wall bridging. The results showed that currents at both polarities are remarkably more significant than the respective duration times. It was also shown that there is a straight relationship between welding speed and feeding speed and this relationship must be followed for obtaining sound beads. A very short positive duration time is enough for arc stability achievement and when the negative duration time is longer than 5 ms its effect on geometry appears. The possibility of optimizing the parameter selection, despite the high inter-correlation amongst them, was demonstrate through a computer program. An approach to reduce the number of variables in this process is also presented.
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This work presents an application of the Mobility Approach to the analysis of the power flow through grillage-like structures. Such structures are usually found in offshore platforms, supporting large and heavy machines. Different wave kinds (longitudinal, flexural and torsional) were initially considered in the power flow analysis between two beams joined in L. Beams excited by an in-plane point force showed strong coupling between longitudinal-flexural waves, while that for out-of-plane point force excitation, flexural-torsional waves coupling represents the most important mechanism of energy transmission. The response determination of grillages by the mobility approach requires the structure to be separated into simple beam-like structural components. Equations for rotations and displacements at the joints of all beams are written for as mobility functions, and moments and forces acting at the joints. A system of equations relating all such internal forces and moments is obtained. This approach was applied to simple grillages. Response results showed good agreement when compared to those provided by Finite Elements.
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Plants and some other organisms including protists possess a complex branched respiratory network in their mitochondria. Some pathways of this network are not energy-conserving and allow sites of energy conservation to be bypassed, leading to a decrease of the energy yield in the cells. It is a challenge to understand the regulation of the partitioning of electrons between the various energy-dissipating and -conserving pathways. This review is focused on the oxidase side of the respiratory chain that presents a cyanide-resistant energy-dissipating alternative oxidase (AOX) besides the cytochrome pathway. The known structural properties of AOX are described including transmembrane topology, dimerization, and active sites. Regulation of the alternative oxidase activity is presented in detail because of its complexity. The alternative oxidase activity is dependent on substrate availability: total ubiquinone concentration and its redox state in the membrane and O2 concentration in the cell. The alternative oxidase activity can be long-term regulated (gene expression) or short-term (post-translational modification, allosteric activation) regulated. Electron distribution (partitioning) between the alternative and cytochrome pathways during steady-state respiration is a crucial measurement to quantitatively analyze the effects of the various levels of regulation of the alternative oxidase. Three approaches are described with their specific domain of application and limitations: kinetic approach, oxygen isotope differential discrimination, and ADP/O method (thermokinetic approach). Lastly, the role of the alternative oxidase in non-thermogenic tissues is discussed in relation to the energy metabolism balance of the cell (supply in reducing equivalents/demand in energy and carbon) and with harmful reactive oxygen species formation.
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Apoptosis, a form of programmed cell death (PCD), has been described as essential for normal organogenesis and tissue development, as well as for the proper function of cell-renewal systems in adult organisms. Apoptosis is also pivotal in the pathogenesis of several different diseases. In this paper we discuss, from two different points of view, the role of apoptosis in parasitic diseases. The description of apoptotic death in three different species of heteroxenic trypanosomatids is reviewed, and considerations on the phylogenesis of apoptosis and on the eventual role of PCD on their mechanism of pathogenesis are made. From a different perspective, an increasing body of evidence is making clear that regulation of host cell apoptosis is an important factor on the definition of a host-pathogen interaction. As an example, the molecular mechanisms by which Trypanosoma cruzi is able to induce apoptosis in immunocompetent cells, in a murine model of Chagas' disease, and the consequences of this phenomenon on the outcome of the experimental disease are discussed.
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DNA double-strand breaks (DSBs) represent a major threat to the genomic stability of eukaryotic cells. DNA repair mechanisms such as non-homologous end joining (NHEJ) are responsible for the maintenance of eukaryotic genomes. Dysfunction of one or more of the many protein complexes that function in NHEJ can lead to sensitivity to DNA damaging agents, apoptosis, genomic instability, and severe combined immunodeficiency. One protein, Pso2p, was shown to participate in the repair of DSBs induced by DNA inter-strand cross-linking (ICL) agents such as cisplatin, nitrogen mustard or photo-activated bi-functional psoralens. The molecular function of Pso2p in DNA repair is unknown, but yeast and mammalian cell line mutants for PSO2 show the same cellular responses as strains with defects in NHEJ, e.g., sensitivity to ICLs and apoptosis. The Pso2p human homologue Artemis participates in V(D)J recombination. Mutations in Artemis induce a variety of immunological deficiencies, a predisposition to lymphomas, and an increase in chromosomal aberrations. In order to better understand the role of Pso2p in the repair of DSBs generated as repair intermediates of ICLs, an in silico approach was used to characterize the catalytic domain of Pso2p, which led to identification of novel Pso2p homologues in other organisms. Moreover, we found the catalytic core of Pso2p fused to different domains. In plants, a specific ATP-dependent DNA ligase I contains the catalytic core of Pso2p, constituting a new DNA ligase family, which was named LIG6. The possible functions of Pso2p/Artemis/Lig6p in NHEJ and V(D)J recombination and in other cellular metabolic reactions are discussed.
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Although echocardiography has been used in rats, few studies have determined its efficacy for estimating myocardial infarct size. Our objective was to estimate the myocardial infarct size, and to evaluate anatomic and functional variables of the left ventricle. Myocardial infarction was produced in 43 female Wistar rats by ligature of the left coronary artery. Echocardiography was performed 5 weeks later to measure left ventricular diameter and transverse area (mean of 3 transverse planes), infarct size (percentage of the arc with infarct on 3 transverse planes), systolic function by the change in fractional area, and diastolic function by mitral inflow parameters. The histologic measurement of myocardial infarction size was similar to the echocardiographic method. Myocardial infarct size ranged from 4.8 to 66.6% when determined by histology and from 5 to 69.8% when determined by echocardiography, with good correlation (r = 0.88; P < 0.05; Pearson correlation coefficient). Left ventricular diameter and mean diastolic transverse area correlated with myocardial infarct size by histology (r = 0.57 and r = 0.78; P < 0.0005). The fractional area change ranged from 28.5 ± 5.6 (large-size myocardial infarction) to 53.1 ± 1.5% (control) and correlated with myocardial infarct size by echocardiography (r = -0.87; P < 0.00001) and histology (r = -0.78; P < 00001). The E/A wave ratio of mitral inflow velocity for animals with large-size myocardial infarction (5.6 ± 2.7) was significantly higher than for all others (control: 1.9 ± 0.1; small-size myocardial infarction: 1.9 ± 0.4; moderate-size myocardial infarction: 2.8 ± 2.3). There was good agreement between echocardiographic and histologic estimates of myocardial infarct size in rats.