974 resultados para third central moment


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El objetivo del presente artículo es hacer una reflexión acerca de la nueva geografía comercial de América Latina, relativa a los acuerdos celebrados con los EE.UU. Frente a las incertidumbres en el ámbito regional y multilateral, hoy existe un cierto predominio de un tercer movimiento en las relaciones económicas internacionales, esto es, la proliferación de tratados bilaterales. Aunque estos tratados asuman diferentes contenidos y obligaciones, en general tienen compromisos más rígidos para los países en desarrollo en América Latina, que las obligaciones firmadas en foros de negociación subjetivamente más amplios (como es el caso de la OMC).

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La autora hace un recorrido por las tendencias que han seguido los estudios del Estado en el siglo XX y para ello, aborda cinco momentos históricos que refieren a autores claves y representativos del pensamiento crítico latinoamericano. Las preguntas: ¿cómo se ha estudiado al Estado en América Latina? y ¿qué desafíos plantean las crisis institucionales a los conceptos tradicionales? delimitan el artículo. Finalmente, hace un balance de las corrientes que han caracterizado cada momento y propone una posible línea de investigación que considera acorde con la compleja y asincrónica realidad latinoamericana.

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Desde una perspectiva que pone énfasis en el logro de resultados y sus obstáculos, este artículo analiza la evolución del proceso del ALCA. Para ello, Bouzas y Svarzman dividen el análisis en cuatro momentos: l. Desde la Primera Cumbre Presidencial (Miami, 1994) hasta la segunda (Santiago, 1998).2. El período que se inicia y termina entre las reuniones ministeriales de San José y Toronto. 3. Desde la reunión de Toronto hasta el encuentro ministerial de Buenos Aires y la Tercera Cumbre Presidencial de Quebec. 4. Y un último momento que empezó en Quebec y que se cerrará con la culminación de las negociaciones en el año 2005.

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El presente trabajo intenta analizar brevemente los distintos aspectos relativos a la inclusión de la inversión extranjera directa en la política comercial común de la Unión Europea, reformada por el Tratado de Lisboa. Inicialmente se hará referencia a la práctica de la UE en el área de inversiones previas al Tratado de Lisboa, acto seguido, se expondrán las interpretaciones sugeridas al concepto de “inversión extranjera directa” en la política comercial común de la Unión Europea, así como también las distintas posturas sobre el alcance de esta política con relación a este concepto, tras la vigencia del Tratado de Lisboa. Finalmente serán descritos los posibles efectos de dicha competencia de la Unión para los tratados bilaterales de inversión celebrados entre sus países miembros, y de estos con terceros países.

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The objective of this work was to determine the rumen fermentation characteristics of maize land races used as forage in central Mexico. In vitro gas production (ml per 200 mg dry matter (DM)) incubations were carried out, and cumulative gas volumes were fitted to the Krishnamoorthy et al. (1991) model. The trial used a split-plot design with cultivation practices associated with maize colour (COL) as the main plot with three levels: white, yellow and black maize; growing periods (PER) were the split plots where PER1, PER2 and PER3 represented the first, second and third periods, respectively and two contrasting zones (Z1 = valley and Z2 = mountain) were used as blocking factors. The principal effects observed were associated with the maturity of the plants and potential gas production increased (P < 0.05) in stems (PER 1 = 51.8, PER2 = 56.3, PER3 = 58.4 ml per 200 mg DM) and in whole plant (PER 1 = 60.9, PER2 = 60.8, PER3= 70.9 ml per 200 mg DM). An inverse effect was observed with fermentation rates in leaves (P < 0.01) with 0.061, 0.053 and 0.0509 (per h) and in whole plant (P < 0.05) with 0.068, 0.057, 0.050 (per h) in PER1, PER2 and PER3 respectively. The digestibility of the neutral-detergent fibre (NDF) decreased with maturity especially in leaves (P < 0.05) with values of 0.71, 0.67 and 0.66 g/kg; in rachis (P < 0.01) 0.75, 0.72, and 0.65 in PER1, PER2 and PER3 respectively. The NDF content in leaves in leaves (668, 705 and 713 g/kg DM for PER1, PER2 and PER3, respectively), stems (580, 594 and 644 g/kg DM) and, husk (663, 774 and, 808 g/kg DM) increased (P < 0.05) with increasing plant maturity, rachis were significantly different between periods (P < 0.01). The structure with-the best nutritive characteristics was the husk, because it had the lowest fibre contents, especially in acid-detergent lignin, with values of 22.6, 28.6 and 37.6 g/kg DM in PER1, PER2 and PER3, respectively.

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Accurate knowledge of lactation curves has an important relevance to management and research of dairy production systems. A number of equations have been proposed to describe the lactation curve, the most widely applied being the gamma equation. The objective of this work was to compare and evaluate candidate functions for their predictive ability in describing lactation curves from central Mexican dairy cows reared under 2 contrasting management systems. Five equations were considered: Gaines ( exponential decay), Wood ( gamma equation), Rook ( Michaelis-Menten x exponential), and 2 more mechanistic ones (Dijkstra and Pollott). A database consisting of 701 and 1283 records of cows in small-scale and intensive systems, respectively, was used in the analysis. Before analysis, the database was divided into 6 groups representing first, second, and third and higher parity cows in both systems. In all cases except second and above parity cows in small-scale systems, all models improved on the Gaines equation. The Wood equation explained much of the variation, but its parameters do not have direct biological interpretation. Although the Rook equation fitted the data well, some of the parameter estimates were not significant. The Dijkstra equation consistently gave better predictions, and its parameters were usually statistically significant and lend themselves to physiological interpretation. As such, the differences between systems and parity could be explained due to variations in theoretical initial milk production at parturition, specific rates of secretory cell proliferation and death, and rate of decay, all of which are parameters in the model. The Pollott equation, although containing the most biology, was found to be over-parameterized and resulted in nonsignificant parameter estimates. For central Mexican dairy cows, the Dijkstra equation was the best option to use in describing the lactation curve.

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Milk supply from Mexican dairy farms does not meet demand and small-scale farms can contribute toward closing the gap. Two multi-criteria programming techniques, goal programming and compromise programming, were used in a study of small-scale dairy farms in central Mexico. To build the goal and compromise programming models, 4 ordinary linear programming models were also developed, which had objective functions to maximize metabolizable energy for milk production, to maximize margin of income over feed costs, to maximize metabolizable protein for milk production, and to minimize purchased feedstuffs. Neither multicriteria approach was significantly better than the other; however, by applying both models it was possible to perform a more comprehensive analysis of these small-scale dairy systems. The multi-criteria programming models affirm findings from previous work and suggest that a forage strategy based on alfalfa, rye-grass, and corn silage would meet nutrient requirements of the herd. Both models suggested that there is an economic advantage in rescheduling the calving season to the second and third calendar quarters to better synchronize higher demand for nutrients with the period of high forage availability.

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Objective: To evaluate the presence of enamel alterations in deciduous maxillary central incisors of infants with unilateral cleft lip and alveolar ridge, with or without cleft palate, and to compare the occurrence and location of these alterations between the central incisor adjacent to the cleft and the contralateral incisor. Design: Intraoral clinical examination was performed after tooth cleaning and drying by a single examiner with the aid of a dental mirror, dental probe, and artificial light, with the child positioned on a dental chair. The defects were recorded in a standardized manner according to the criteria of the Modified Developmental Defects of Enamel Index. Setting: Hospital for Rehabilitation of Craniofacial Anomalies (HRAC) at Bauru, Sao Paulo, Brazil. Patients: One hundred one infants were evaluated. All were white, of both genders, aged 12 to 36 months and had at least two thirds of the crowns of maxillary incisors erupted. Results: Demarcated opacity was the most common defect at both cleft and noncleft sides, followed by diffuse opacity. The occurrence of hypoplasia at the cleft side was 11.8%. Most defects affected less than one third of the crown. Conclusion: The occurrence of enamel defects in deciduous maxillary central incisors of patients with unilateral cleft lip was 42.6%, mainly affecting the cleft side as to both number and severity.

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Pilocarpine (cholinergic muscarinic agonist) injected peripherally may act centrally to produce pressor responses; in the present study, using c-fos immunoreactive expression, we investigated the forebrain and brainstem areas activated by pressor doses of intravenous (i.v.) pilocarpine. In addition, the importance of vasopressin secretion and/or sympathetic activation and the effects of lesions in the anteroventral third ventricle (AV3V) region in awake rats were also investigated. In male Holtzman rats, pilocarpine (0.04 to 4 mu mol/kg b.w.) i.v. induced transitory hypotension followed by long lasting hypertension. Sympathetic blockade with prazosin (1 mg/kg b.w.) i.v. or AV3V lesions (1 day) almost abolished the pressor response to i. v. pilocarpine (2 mu mol/kg b.w.), whereas the vasopressin antagonist (10 mu g/kg b.w.) i.v. reduced the response to pilocarpine. Pilocarpine (2 and 4 mu mol/kg b.w.) i.v. increased the number of c-fos immunoreactive cells in the subfornical organ, paraventricular and supraoptic nuclei of the hypothalamus, organ vasculosum of the lamina terminalis, median preoptic nucleus, nucleus of the solitary tract and caudal and rostral ventrolateral medulla. These data suggest that i.v. pilocarpine activates specific forebrain and brainstem mechanisms increasing sympathetic activity and vasopressin secretion to induce pressor response. (C) 2011 Elsevier B.V. All rights reserved.

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Post-colonial movements for independence are voices of autonomy and independence before the onslaught of global organizations and cultures. This paper introduces the second set of themed papers in Gender, Place and Culture (see 13.2) which contains some of these voices, emanating from intensely private as well as communal and street kitchens; where women proclaim their visibility, economic value as food producers and transformers. The essays by Christie on the fiesta kitchens of central Mexico, Schroeder on the community kitchens of Bolivia and Peru, Robson on Islamic kitchens in rural Nigeria, Wardrop on the street vendors of south Durban and Pascali on Italian migrant kitchens in North East America, all acknowledge the vital contexts of 'development', urbanization, migration and industrialization to their stories, while also highlighting powerful elements of resistance and autonomy within the kitchen. As such the Western gaze records not so much the impacts of globalization as its cooking and transformation into something new, a hybrid dish, customized for local consumption.

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The main theme of this thesis is that there is a common structural basis for drugs acting on the central nervous system (CNS), and that this concept may be used to design new CNS-active drugs which have greater specificity and hence less side-effects. To develop these ideas, the biological basis of how drugs modify CMS neurotransmission is described, and illustrated using dopaminergic pathways. An account is then given of the use of physicochemical concepts in contemporary drug design. The complete conformational analysis of several antipsychotic drugs is used to illustrate some of these techniques in the development of a model for antipsychotic drug action. After reviewing current structure-activity studies in several classes of CNS drugs (antipsychotics, anti-depressants, stimulants, hal1ucinogens, anticonvulsants and analgesics), a hypothesis for a common structural basis of CNS drug action is proposed- This is based on a topographical comparison of the X-ray structures of eight representative CNS-active drugs, and consists of three parts: 1.there is a common structural basis for the activity of many different CNS-active drug classes; 2. an aromatic ring and a nitrogen atom are the primary binding groups whose topographical arrangement is fundamental to the activity of these drug classes; 3. the nature and placement of secondary binding determines different classes of CNS drug activity. A four-Point model for this common structural basis is then defined using 14- CNS-active drug structures that include the original eight used in proposing the hypothesis. The coordinates of this model are: R1 (0. 3.5, 0), R2 (0, -3.5, O), N (4.8. -0.3, 1.4), and R3 (6.3, 1.3, 0), where R1 and R2 represent the point locations of a hydrophobic interaction of the common aromatic ring with a receptor, and R3 locates the receptor point for a hydrogen bond involving the common nitrogen, N. Extended structures were used to define the receptor points R1, R2 and R3, and the complete conformational space of each of the 14 molecules was considered. It is then shoun that the model may be used to predict whether a given structure is likely to show CNS activity: a search over 1,000 entries in the current Merck Index shows a high probability (82%) of CNS activity in compounds fitting the structural model. Analysis of CNS neurotransmitters and neuropeptides shows that these fit the common model well. Based on the available evidence supporting chemical evolution, protein evolution, and the evolution of neurotransmitter functions, it is surmised that the aromatic ring/nitrogen atom pharmacophore proposed in the common model supports the idea of the evolution of CNS receptors and their neurotransmitters, possibly from an aromatic amine or acety1cho1ine acting as a primaeval communicating molecule. The third point in the hypothesis trilogy is then addressed. The extensive conformation-activity analyses that have resulted in well-defined models for five separate CNS drug classes are used to map out the locations of secondary binding groups relative to the common model for anti-psychotics, antidepressants, analgesics, anticholinergics, and anticonvulsants. With this information, and knowledge derived from receptor-binding data, it is postulated that drugs having specified activity could be designed. In order to generate novel structures having a high probability of CNS-activity, a process of drug design is described in which known CNS structures are superimposed topographically using the common model as a template. Atoms regarded as superfluous may be selectively deleted and the required secondary binding groups added in predicted locations to give novel structures. It is concluded that this process provides the basis for the rational design of new lead compounds which could further be optimized for potent and specific CNS activity.

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Purpose – This paper aims to propose a conceptual framework to explore the link between strategic human resource management (SHRM) and firm performance of the coal mining companies in Central Queensland (CQ), Australia.

Design/methodology/approach – The paper reviews literature relating to the process and issues of transforming human resource practices and industrial relations of the coal industry in Australia for the past decade. Theoretical development and empirical studies on the SHRM-performance linkage are discussed. Based on the literature review, the paper develops an integrated model for testing the relationship between SHRM and firm performance in the context of CQ's coalmines and proposes a number of research propositions.

Findings – Three perceivable outcomes are likely derived from application of this framework in the field. First, a testing of the linkage between strategic HRM and firm performance in the coal industry, using an integrated approach, would complement the empirical deficiency of treatments on the prior SHRM models. Second, data at firm level could be collected to develop a better understanding of how the adoption of strategic HRM practices in coal companies can affect firm performance. Third, the extent of flexibility practices, use of contractors and associated management practices could be identified.

Originality/value – The coal industry is central to economic development of regional Queensland. The industry contributes substantially to GDP via employment, investment and product export. An exploration of the impact of SHRM on the coal industry will likely result in identifying some best practices that could be potentially adopted in the wider business community to foster regional economic development in Australia and worldwide.

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David Tittensor offers a groundbreaking new perspective on the Gülen movement, a Turkish Muslim educational activist network that emerged in the 1960s and has grown into a global empire with an estimated worth of $25 billion. Named after its leader Fethullah Gülen, the movement has established more than 1,000 secular educational institutions in over 140 countries, aiming to provide holistic education that incorporates both spirituality and the secular sciences.

Despite the movement's success, little is known about how its schools are run, or how Islam is operationalized. Drawing on thirteen months of ethnographic fieldwork in Turkey, Tittensor explores the movement's ideo-theology and how it is practiced in the schools. His interviews with both teachers and graduates from Africa, Indonesia, Central Asia, and Turkey show that the movement is a missionary organization, but of a singular kind: its goal is not simply widespread religious conversion, but a quest to recoup those Muslims who have apparently lost their way and to show non-Muslims that Muslims can embrace modernity and integrate into the wider community. Tittensor also examines the movement's operational side and shows how the schools represent an example of Mohammad Yunus's social business model: a business with a social cause at its heart.

The House of Service is an insightful exploration of one of the world's largest transnational Muslim associations, and will be invaluable for those seeking to understand how Islam will be perceived and practiced in the future.

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Medulloblastoma is curable in approximately 70% of patients. Over the past decade, progress in improving survival using conventional therapies has stalled, resulting in reduced quality of life due to treatment-related side effects, which are a major concern in survivors. The vast amount of genomic and molecular data generated over the last 5-10 years encourages optimism that improved risk stratification and new molecular targets will improve outcomes. It is now clear that medulloblastoma is not a single-disease entity, but instead consists of at least four distinct molecular subgroups: WNT/Wingless, Sonic Hedgehog, Group 3, and Group 4. The Medulloblastoma Down Under 2013 meeting, which convened at Bunker Bay, Australia, brought together 50 leading clinicians and scientists. The 2-day agenda included focused sessions on pathology and molecular stratification, genomics and mouse models, high-throughput drug screening, and clinical trial design. The meeting established a global action plan to translate novel biologic insights and drug targeting into treatment regimens to improve outcomes. A consensus was reached in several key areas, with the most important being that a novel classification scheme for medulloblastoma based on the four molecular subgroups, as well as histopathologic features, should be presented for consideration in the upcoming fifth edition of the World Health Organization's classification of tumours of the central nervous system. Three other notable areas of agreement were as follows: (1) to establish a central repository of annotated mouse models that are readily accessible and freely available to the international research community; (2) to institute common eligibility criteria between the Children's Oncology Group and the International Society of Paediatric Oncology Europe and initiate joint or parallel clinical trials; (3) to share preliminary high-throughput screening data across discovery labs to hasten the development of novel therapeutics. Medulloblastoma Down Under 2013 was an effective forum for meaningful discussion, which resulted in enhancing international collaborative clinical and translational research of this rare disease. This template could be applied to other fields to devise global action plans addressing all aspects of a disease, from improved disease classification, treatment stratification, and drug targeting to superior treatment regimens to be assessed in cooperative international clinical trials.