886 resultados para Paths and cycles (Graph theory).
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We discuss several ontological properties of explicit mathematics and operational set theory: global choice, decidable classes, totality and extensionality of operations, function spaces, class and set formation via formulas that contain the definedness predicate and applications.
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Quarks were introduced 50 years ago opening the road towards our understanding of the elementary constituents of matter and their fundamental interactions. Since then, a spectacular progress has been made with important discoveries that led to the establishment of the Standard Theory that describes accurately the basic constituents of the observable matter, namely quarks and leptons, interacting with the exchange of three fundamental forces, the weak, electromagnetic and strong force. Particle physics is now entering a new era driven by the quest of understanding of the composition of our Universe such as the unobservable (dark) matter, the hierarchy of masses and forces, the unification of all fundamental interactions with gravity in a consistent quantum framework, and several other important questions. A candidate theory providing answers to many of these questions is string theory that replaces the notion of point particles by extended objects, such as closed and open strings. In this short note, I will give a brief overview of string unification, describe in particular how quarks and leptons can emerge and discuss what are possible predictions for particle physics and cosmology that could test these ideas.
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Quarks were introduced 50 years ago opening the road towards our understanding of the elementary constituents of matter and their fundamental interactions. Since then, a spectacular progress has been made with important discoveries that led to the establishment of the Standard Theory that describes accurately the basic constituents of the observable matter, namely quarks and leptons, interacting with the exchange of three fundamental forces, the weak, electromagnetic and strong force. Particle physics is now entering a new era driven by the quest of understanding of the composition of our Universe such as the unobservable (dark) matter, the hierarchy of masses and forces, the unification of all fundamental interactions with gravity in a consistent quantum framework, and several other important questions. A candidate theory providing answers to many of these questions is string theory that replaces the notion of point particles by extended objects, such as closed and open strings. In this short note, I will give a brief overview of string unification, describe in particular how quarks and leptons can emerge and discuss what are possible predictions for particle physics and cosmology that could test these ideas.
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Objective. The purpose of the study is to provide a holistic depiction of behavioral & environmental factors contributing to risky sexual behaviors among predominantly high school educated, low-income African Americans residing in urban areas of Houston, TX utilizing the Theory of Gender and Power, Situational/Environmental Variables Theory, and Sexual Script Theory. ^ Methods. A cross-sectional study was conducted via questionnaires among 215 Houston area residents, 149 were women and 66 were male. Measures used to assess behaviors of the population included a history of homelessness, use of crack/cocaine among several other illicit drugs, the type of sexual partner, age of participant, age of most recent sex partner, whether or not participants sought health care in the last 12 months, knowledge of partner's other sexual activities, symptoms of depression, and places where partner's were met. In an effort to determine risk of sexual encounters, a risk index employing the variables used to assess condom use was created categorizing sexual encounters as unsafe or safe. ^ Results. Variables meeting the significance level of p<.15 for the bivariate analysis of each theory were entered into a binary logistic regression analysis. The block for each theory was significant, suggesting that the grouping assignments of each variable by theory were significantly associated with unsafe sexual behaviors. Within the regression analysis, variables such as sex for drugs/money, low income, and crack use demonstrated an effect size of ≥±1, indicating that these variables had a significant effect on unsafe sexual behavioral practices. ^ Conclusions. Variables assessing behavior and environment demonstrated a significant effect when categorized by relation to designated theories. ^
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In this paper we build a theoretical model on the wage effect of skilled emigration to the fluctuations in real exchange rate through the relative prices of nontradables. Our theoretical model predicts that skilled emigration is associated with an increase in the prices of nontradable, which in turn appreciates the exchange rate. We provide robust empirical support to a higher skilled emigration associated with higher prices in nontradables and appreciation of the real effective exchange rate. Based on two samples of countries with 51 and 67 observations, in 1990 and 2000 respectively, we find robust empirical support to a higher skilled emigration associated with higher prices in nontradables and appreciation of the REER. In addition, the support for the remittance-channel of the Dutch disease is also significant; overall, our findings corroborate the remittance-based Dutch disease phenomenon by providing an additional channel through which the labor mobility across borders affects the real exchange rate volatility.
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La prevalencia de las alergias está aumentando desde mediados del siglo XX, y se estima que actualmente afectan a alrededor del 2-8 % de la población, pero las causas de este aumento aún no están claras. Encontrar el origen del mecanismo por el cual una proteína inofensiva se convierte en capaz de inducir una respuesta alérgica es de vital importancia para prevenir y tratar estas enfermedades. Aunque la caracterización de alérgenos relevantes ha ayudado a mejorar el manejo clínico y a aclarar los mecanismos básicos de las reacciones alérgicas, todavía queda un largo camino para establecer el origen de la alergenicidad y reactividad cruzada. El objetivo de esta tesis ha sido caracterizar las bases moleculares de la alergenicidad tomando como modelo dos familias de panalergenos (proteínas de transferencia de lípidos –LTPs- y taumatinas –TLPs-) y estudiando los mecanismos que median la sensibilización y la reactividad cruzada para mejorar tanto el diagnóstico como el tratamiento de la alergia. Para ello, se llevaron a cabo dos estrategias: estudiar la reactividad cruzada de miembros de familias de panalérgenos; y estudiar moléculas-co-adyuvantes que pudieran favorecer la capacidad alergénica de dichas proteínas. Para estudiar la reactividad cruzada entre miembros de la misma familia de proteínas, se seleccionaron LTPs y TLPs, descritas como alergenos, tomando como modelo la alergia a frutas. Por otra parte, se estudiaron los perfiles de sensibilización a alérgenos de trigo relacionados con el asma del panadero, la enfermedad ocupacional más relevante de origen alérgico. Estos estudios se llevaron a cabo estandarizando ensayos tipo microarrays con alérgenos y analizando los resultados por la teoría de grafos. En relación al estudiar moléculas-co-adyuvantes que pudieran favorecer la capacidad alergénica de dichas proteínas, se llevaron a cabo estudios sobre la interacción de los alérgenos alimentarios con células del sistema inmune humano y murino y el epitelio de las mucosas, analizando la importancia de moléculas co-transportadas con los alérgenos en el desarrollo de una respuesta Th2. Para ello, Pru p 3(LTP y alérgeno principal del melocotón) se selección como modelo para llevarlo a cabo. Por otra parte, se analizó el papel de moléculas activadoras del sistema inmune producidas por patógenos en la inducción de alergias alimentarias seleccionando el modelo kiwi-alternaria, y el papel de Alt a 1, alérgeno mayor de dicho hongo, en la sensibilización a Act d 2, alérgeno mayor de kiwi. En resumen, el presente trabajo presenta una investigación innovadora aportando resultados de gran utilidad tanto para la mejora del diagnóstico como para nuevas investigaciones sobre la alergia y el esclarecimiento final de los mecanismos que caracterizan esta enfermedad. ABSTRACT Allergies are increasing their prevalence from mid twentieth century, and they are currently estimated to affect around 2-8% of the population but the underlying causes of this increase remain still elusive. The understanding of the mechanism by which a harmless protein becomes capable of inducing an allergic response provides us the basis to prevent and treat these diseases. Although the characterization of relevant allergens has led to improved clinical management and has helped to clarify the basic mechanisms of allergic reactions, it seems justified in aspiring to molecularly dissecting these allergens to establish the structural basis of their allergenicity and cross-reactivity. The aim of this thesis was to characterize the molecular basis of the allergenicity of model proteins belonging to different families (Lipid Transfer Proteins –LTPs-, and Thaumatin-like Proteins –TLPs-) in order to identify mechanisms that mediate sensitization and cross reactivity for developing new strategies in the management of allergy, both diagnosis and treatment, in the near future. With this purpose, two strategies have been conducted: studies of cross-reactivity among panallergen families and molecular studies of the contribution of cofactors in the induction of the allergic response by these panallergens. Following the first strategy, we studied the cross-reactivity among members of two plant panallergens (LTPs , Lipid Transfer Proteins , and TLPs , Thaumatin-like Proteins) using the peach allergy as a model. Similarly, we characterized the sensitization profiles to wheat allergens in baker's asthma development, the most relevant occupational disease. These studies were performed using allergen microarrays and the graph theory for analyzing the results. Regarding the second approach, we analyzed the interaction of plant allergens with immune and epithelial cells. To perform these studies , we examined the importance of ligands and co-transported molecules of plant allergens in the development of Th2 responses. To this end, Pru p 3, nsLTP (non-specific Lipid Transfer Protein) and peach major allergen, was selected as a model to investigate its interaction with cells of the human and murine immune systems as well as with the intestinal epithelium and the contribution of its ligand in inducing an allergic response was studied. Moreover, we analyzed the role of pathogen associated molecules in the induction of food allergy. For that, we selected the kiwi- alternaria system as a model and the role of Alt a 1 , major allergen of the fungus, in the development of Act d 2-sensitization was studied. In summary, this work presents an innovative research providing useful results for improving diagnosis and leading to further research on allergy and the final clarification of the mechanisms that characterize this disease.
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In the first part of this work, we show how certain techniques from quantum information theory can be used in order to obtain very sharp embeddings between noncommutative Lp-spaces. Then, we use these estimates to study the classical capacity with restricted assisted entanglement of the quantum erasure channel and the quantum depolarizing channel. In particular, we exactly compute the capacity of the first one and we show that certain nonmultiplicative results hold for the second one.
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The purpose of this research report is to present an overview of an ongoing, international project designed to chart the developmental paths and activities of sport coaches. This brief report includes three sections: (a) conceptual framework used to guide the project, (b) project design and methodology, and (c) results from pilot studies with a sample of 15 successful coaches working in different sport contexts in the United States Unlike the findings for athletic profiles, where several trends across coaching contexts were evident, only one trend was found in how these diverse groups of coaches invested their time in coach developmental activities. In relation to other coaching activities very little time was devoted to formal coach education on an annual basis. The results reinforce the need to consider the coaching context when examining coach development and when designing coach development initiatives.
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The thousands of books and articles on Charles de Gaulle's policy toward European integration, whether written by historians, social scientists, or commentators, universally accord primary explanatory importance to the General's distinctive geopolitical ideology. In explaining his motivations, only secondary significance, if any at all, is attached to commercial considerations. This paper seeks to reverse this historiographical consensus by examining the four major decisions toward European integration during de Gaulle's presidency: the decisions to remain in the Common Market in 1958, to propose the Foucher Plan in the early 1960s, to veto British accession to the EC, and to provoke the "empty chair" crisis in 1965-1966, resulting in the "Luxembourg Compromise." In each case, the overwhelming bulk of the primary evidence-speeches, memoirs, or government documents-suggests that de Gaulle's primary motivation was economic, not geopolitical or ideological. Like his predecessors and successors, de Gaulle sought to promote French industry and agriculture by establishing protected markets for their export products. This empirical finding has three broader implications: (1) For those interesred in the European Union, it suggests that regional integration has been driven primarily by economic, not geopolitical considerations--even in the "least likely" case. (2) For those interested in the role of ideas in foreign policy, it suggests that strong interest groups in a democracy limit the impact of a leader's geopolitical ideology--even where the executive has very broad institutional autonomy. De Gaulle was a democratic statesman first and an ideological visionary second. (3) For those who employ qualitative case-study methods, it suggests that even a broad, representative sample of secondary sources does not create a firm basis for causal inference. For political scientists, as for historians, there is in many cases no reliable alternative to primary-source research.
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Network governance of collective learning processes is an essential approach to sustainable development. The first section of the article briefly refers to recent theories about both market and government failures that express scepticism about the way framework conditions for market actors are set. For this reason, the development of networks for collective learning processes seems advantageous if new solutions are to be developed in policy areas concerned with long-term changes and a stepwise internalisation of externalities. With regard to corporate actors’ interests, the article shows recent insights from theories about the knowledge-based firm, where the creation of new knowledge is based on the absorption of societal views. This concept shifts the focus towards knowledge generation as an essential element in the evolution of sustainable markets. This involves at the same time the development of new policies. In this context innovation-inducing regulation is suggested and discussed. The evolution of the Swedish, German and Dutch wind turbine industries are analysed based on the approach of governance put forward in this article. We conclude that these coevolutionary mechanisms may take for granted some of the stabilising and orientating functions previously exercised by basic regulatory activities of the state. In this context, the main function of the governments is to facilitate learning processes that depart from the government functions suggested by welfare economics.
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The thousands of books and articles on Charles de Gaulle's policy toward European integration, whether written by historians, political scientists, or commentators, universally accord primary explanatory importance to the General's distinctive geopolitical ideology. In explaining his motivations, only secondary significance, if any at all, is attached to commercial considerations. This paper seeks to reverse this historiographical consensus by the four major decisions toward European integration taken under de Gaulle's Presidency: the decisions to remain in the Common Market in 1958, to propose the Fouchet Plan in the early 1960s, to veto British accession to the EC, and to provoke the "empty chair" crisis in 1965-1966, resulting in Luxembourg Compromise. In each case, the overwhelming bulk of the primary evidence speeches, memoirs, or government documents suggests that de Gaulle's primary motivation was economic, not geopolitical or ideological. Like his predecessors and successors, de Gaulle sought to promote French industry and agriculture by establishing protected markets for their export products. This empirical finding has three broader implications: (1) For those interested in the European Union, it suggests that regional integration has been driven primarily by economic, not geopolitical considerations even in the least likely case. (2) For those interested in the role of ideas in foreign policy, it suggests that strong interest groups in a democracy limit the impact of a leaders geopolitical ideology even where the executive has very broad institutional autonomy. De Gaulle was a democratic statesman first and an ideological visionary second. (3) For those who employ qualitative case-study methods, it suggests that even a broad, representative sample of secondary sources does not create a firm basis for causal inference. For political scientists, as for historians, there is in many cases no reliable alternative to primary source research.
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Mode of access: Internet.