Large quantum gravity effects: Cylindrical waves in four dimensions

Linearly polarized cylindrical waves in four-dimensional vacuum gravity are mathematically equivalent to rotationally symmetric gravity coupled to a Maxwell (or Klein-Gordon) field in three dimensions. The quantization of this latter system was performed by Ashtekar and Pierri in a recent work. Employing that quantization, we obtain here a complete quantum theory which describes the four-dimensional geometry of the Einstein-Rosen waves. In particular, we construct regularized operators to represent the metric. It is shown that the results achieved by Ashtekar about the existence of important quantum gravity effects in the Einstein-Maxwell system at large distances from the symmetry axis continue to be valid from a four-dimensional point of view. The only significant difference is that, in order to admit an approximate classical description in the asymptotic region, states that are coherent in the Maxwell field need not contain a large number of photons anymore. We also analyze the metric fluctuations on the symmetry axis and argue that they are generally relevant for all of the coherent states.Comment: Version accepted for publication in Int. J. Mod. Phys.

Classification, characterisation and strategies for improvement of cattle and sheep pasture systems in marginal areas of Southern Chile

Pasture-based livestock systems in farms with medium or low size are especially important in less favored areas and are valuable for society. For these systems to survive, it is necessary to obtain an acceptable level of productivity and ensure commercialization of the products. This study was carried out in the district of Rio Ibáñez, General Carrera Province, in the XI (Aysén) Region of Chile. The sample consisted of 28 small-scale livestock farmers with dual-purpose cattle production; 16 of them also produced sheep for meat. The empirical data produced 55 variables which were subjected to multivariate analysis; three main components were obtained which explain 72.1 % of the variance. By cluster analysis it was obtained four groups with characteristics which varied by farm size, age and personal situation of farmers, farm management and farm profitability. The principal problems found are low productivity in the herds and the poor marketing channels of animals produced. In two groups, due to the low size and poor management, the profitability of the farms is very low and this may compromise their future. To improve production systems, the training and advice of farmers should be strengthened, investment should be supported, especially for young people, and the farmer partnership should be promoted. There is also a need to diversify the families' sources of income (sale of other farm products or handicrafts and touristic activities).Ministerio de Economía de Chile Innova-CORFO Project 11 NTEC 1279

Classification, characterisation and strategies for improvement of cattle and sheep pasture systems in marginal areas of Southern Chile

Pasture-based livestock systems in farms with medium or low size are especially important in less favored areas and are valuable for society. For these systems to survive, it is necessary to obtain an acceptable level of productivity and ensure commercialization of the products. This study was carried out in the district of Rio Ibáñez, General Carrera Province, in the XI (Aysén) Region of Chile. The sample consisted of 28 small-scale livestock farmers with dual-purpose cattle production; 16 of them also produced sheep for meat. The empirical data produced 55 variables which were subjected to multivariate analysis; three main components were obtained which explain 72.1 % of the variance. By cluster analysis it was obtained four groups with characteristics which varied by farm size, age and personal situation of farmers, farm management and farm profitability. The principal problems found are low productivity in the herds and the poor marketing channels of animals produced. In two groups, due to the low size and poor management, the profitability of the farms is very low and this may compromise their future. To improve production systems, the training and advice of farmers should be strengthened, investment should be supported, especially for young people, and the farmer partnership should be promoted. There is also a need to diversify the families' sources of income (sale of other farm products or handicrafts and touristic activities).Ministerio de Economía de Chile Innova-CORFO Project 11 NTEC 1279

Evaluating mountain goat dairy systems for conversion to the organic model, using a multicriteria method

Organic farming conserves natural resources, promotes biodiversity, guarantees animal welfare and obtains healthy products from raw materials through natural processes. In order to evaluate possibilities of increasing organic animal production, this study proposes a farm-scale multicriteria method for assessing the conversion of dairy goat systems to the organic model. In addition, a case study in the Northern Sierra of Seville, southern Spain, is analysed. A consensus of expert opinions and a field survey are used to validate a list of potential indicators and issues for assessing the conversion, which consider not only the European Community regulations for organic livestock farming, but also agroecological principles. As a result, the method includes 56 variables integrated in nine indicators: Nutritional management, Sustainable pasture management, Soil fertility and contamination, Weed and pest control, Disease prevention, Breeds and reproduction, Animal welfare, Food safety and Marketing and management. The nine indicators are finally integrated in a global index named OLPI (Organic Livestock Proximity Index). Application of the method to a case study with 24 goat farms reveals an OLPI value of 46.5% for dairy goat farms located in mountain areas of southern Spain. The aspects that differ most from the agroecological model include soil management, animal nutrition and product marketing. Results of the case study indicate that the proposed method is easy to implement and is useful for quantifying the approximation of conventional farms to an organic model

Desarrollo de un programa de educación nutricional y valoración del cambio de hábitos alimentarios saludables en una población de estudiantes de Enseñanza Secundaria Obligatoria

[email protected]ón: La adolescencia se considera un periodo crítico en la adquisición y configuración de hábitos alimentarios y de un estilo de vida saludable para el futuro joven y que probablemente serán perdurables en la edad adulta. La obesidad infantil y juvenil es un problema de Salud Pública cuyo control pasa necesariamente por la prevención y la educación nutricional. Objetivos: Evaluar el estado nutricional de los adolescentes y determinar la proporción con sobrepeso u obesidad y establecer un programa de Intervención Nutricional y analizar la mejora en el patrón de hábitos alimentarios en los adolescentes. Métodos: El estudio se ha realizado sobre una población de 372 alumnos de ESO del IES de la ciudad de Gandía (Valencia). Resultados: El 37,8% de los adolescentes ha mejorado el grado de la calidad de la dieta. Aquellos que consumen una dieta de muy buena calidad ha pasado de ser del 30,0% al 58,6%. También es significativo el número de alumnos que han comenzado a desayunar y los que han dejado de tomar bollería industrial en esta ingesta. Es estadísticamente significativo el descenso de adolescentes que acuden habitualmente a un local de comida rápida y de aquellos que han dejado de tomar de forma regular "chucherías" y golosinas. Los datos del Índice KIDMED muestran que (p < 0,001) el 47,4% de los alumnos han mejorado en cuanto ala calidad de la dieta y ninguno ha empeorado. Discusión: Antes de comenzar el programa un 30% de los alumnos seguía una dieta de buena calidad equiparable a la Dieta Mediterránea tradicional y tras la Educación este porcentaje pasó a ser del 58,6%. El 47,4% de los alumnos con sobrepeso u obesidad que recibieron Educación e Intervención Nutricional han mejorado la calidad de su dieta y el porcentaje de los que seguían una dieta de muy buena calidad pasó de 28,9% al 71,0%.Introduction: Adolescence is a critical period for the acquisition and configuration of healthy dietary habits and lifestyle for the young future, which will likely persist throughout the adulthood. Paediatric and juvenile obesity is a public health problem which control necessarily implies prevention and nutritional education. Objectives: To evaluate the nutritional status of the adolescents and determine the proportion with overweight or obesity, and to establish a Nutritional Intervention Programme and analyse the improvement in the pattern of dietary habits among the adolescents. Methods: The study has been carried out in a population of 372 Obligatory Secondary Education (OSE) students from the Institute of Secondary Education of Gandía (Valencia). Results: 37.8% of the adolescents have improved the level of their diet quality. Those consuming a high quality diet have increased from 30.0% to 58.6%. Also significant is the number of students that have taken up having breakfast and those having discontinued taking industrial bakery with this meal. The decrease in the number of adolescents going to fast food places and of those that have discontinued eating candies regularly isstatistically significant. The data from the KIDMED index show that 47.4% (p < 0.001) of de the students have improved the quality of their diet and in none of them it has worsened. Discussion: Before starting the programme, 30% of the students followed a high quality diet comparable to the traditional Mediterranean Diet, and after the education programme, this percentage increased to 58.6%. Forty-seven point four percent of overweighed or obese students receiving the Nutritional Education and Intervention have improved their diet quality and the percentage of those following a high quality diet varied from 28.9% to 71.0%

Cornered by reality: circuit minors

The present study examines a category of migrant children named “circuit minors.” This category includes unaccompanied migrant children and adolescents who cross the border continuously for various reasons and are typically associated with criminal gangs and human and drug traffickers. The aim of this paper is to highlight the problem and consider the risks and the state of social vulnerability in which this population lives. These categories of children and adolescent migrants are identified through a review of the literature, newspaper archives, and official statistics. The study draws on interviews with key informants to characterize this population. We conclude that there is a need to review existing frameworks for the protection of migrant children and to create an action protocol for officials who have contact with these children to ensure their best interests

The relationship between truncation and phosphorylation at the C-terminus of tau protein in the paired helical filaments of Alzheimer's disease

Acknowledgements: Authors want to express their gratitude to Dr. P. Davies (Albert Einstein College of Medicine, Bronx, NY, USA) and Lester I. Binder (NorthWestern, Chicago, IL, USA) for the generous gift of mAbs (TG-3, Alz-50, and MC1), and (TauC-3), respectively, and to M. en C. Ivan J. Galván-Mendoza for his support in confocal microscopy, and Ms. Maricarmen De Lorenz for her secretarial assistance. We also want to express our gratitude to the Mexican Families who donate the brain of their loved ones affected with Alzheimer's disease, and made possible our research. This work was financially supported by CONACyT grant, No. 142293 (For R.M).Peer reviewedPublisher PD

Evolution des exploitations ovines et caprines en Méditerranée durant les dix dernières années. I. Proposition d'une méthodologie d'étude

L’objectif de ce travail est l’élaboration d’une méthode d’analyse comparative interrégionale de la situation et des évolutions des systèmes de production ovine et caprine. Des questionnaires d’enquête différents sont élaborés à destination des éleveurs d’une part, des agents de développement puis des personnes chargées de la commercialisation d’autre part. Des analyses statistiques de variance sont utilisées pour construire des typologies d’exploitation sur la base de la situation actuelle et de l’évolution des exploitations au cours des 10 dernières années. La méthode d’analyse clinique des écosystèmes a pour objet : (i) de connaître les points forts et les points faibles des systèmes et les relations de cause à effet ; (ii) de prévoir de manière prospective l’évolution future de chaque type d’exploitation ; et (iii) de proposer des actions concrètes pour optimiser les perspectives favorables de chaque système. Cette démarche s’inscrit dans l’Observatoire des systèmes de production ovine et caprine du réseau FAO/CIHEAM de recherche coopérative sur les ovins et les caprins.“Evolution of the sheep and goat farms in the Mediterranean over the last ten years. I. Proposal of a study methodology”. The main objective of this paper is to develop a methodology that could be used in diverse regions to make a comparative analysis of situation and changes that may occur in goat and sheep sectors among different regions from the same or different countries. This process has been elaborated for breeders on one hand, for extension and commercial agents on the other. Statistical analysis of variance is used to build up a typology of farms on the basis of the actual situation and changes in farms for the 10 last years. The method of clinical analysis of variance of ecosystems is used to: (i) determine system strengths and weaknesses and the cause-result relationships; (ii) foresee system evolution based on the established cluster; and (iii) propose actions to optimize future evolution in every system according to real possibilities in each particular case. This initiative is an action of the Monitoring Body of sheep and goat production systems of the FAO/CIHEAM network of cooperative research on sheep and goats

Evolution des indicateurs technico-économiques des exploitations caprines laitières pastorales de l’Andalousie (2006-2008)

The aim of this work is to analyse the evolution of 10 technical-economic indicators during the period 2006-2008 in 6 pastoral farms of Andalusia (Spain) in order to observe the most determinant factors for the viability of systems. For the technical-economic analysis, an adaptation of the FAO/CIHEAM indicators list has been used. Values of indicators for each year and also for the whole of the period have been obtained. By consequence of increases of quantity and price of feed, economic margins of farms decreased from 2006 to 2008. Although the milk prices also increased, the proportion of the increase was less than in the feed price. While in 2008 the family net margin and, overall, the business net margin per litre of milk sold, were very low, the family net margin per unit of family labour was fairly acceptable. The meaning of this situation is that, at present, farms can survive because a part of the pay of family workers is used to purchase feed. Several regression analyses have been made. Only in two cases is there a significant level: the business net margin per litre of milk sold in comparison to the milk sold per goat and the family net margin per unit of family labour in comparison to the total labour.L’objectif de cet article est d’analyser l’évolution de 10 indicateurs technico-économiques pendant la période 2006-2008 dans 6 exploitations pastorales de l’Andalousie (Espagne) afin d’observer les facteurs qui déterminent la viabilité des systèmes. Pour réaliser l’analyse technico-économique, on a utilisé des indicateurs adaptés de la liste de FAO/CIHEAM. On a obtenu les valeurs des indicateurs pour chaque année et aussi pour l’ensemble de la période. Les marges économiques des exploitations ont descendu entre 2006 et 2008 à cause de l’augmentation des quantités et des prix des aliments consommés par les chèvres. Bien que le prix du lait ait aussi augmenté, la proportion de cette augmentation a été inférieure à celle du prix des aliments. Tandis qu’en 2008, la marge nette familiale et, surtout, la marge nette de l’entreprise par litre de lait vendu ont été très basses, la marge nette familiale par UTH a été plus ou moins acceptable. Cette situation implique que, actuellement, les exploitations peuvent survivre parce qu’une partie du salaire qui devrait être assigné aux travailleurs familiaux est destinée à l’achat d’aliments pour les chèvres. Plusieurs analyses de régression ont été réalisées. Uniquement dans deux cas, on a trouvé un niveau de signification : la marge nette de l’entreprise par litre de lait vendu selon le lait vendu par chèvre et la marge nette familiale par UTH selon la main-d’œuvre totale