478 research outputs found
The two-loop five-particle amplitude in supergravity
We compute for the first time the two-loop five-particle amplitude in
supergravity. Starting from the known integrand, we perform an
integration-by-parts reduction and express the answer in terms of uniform
weight master integrals. The latter are known to evaluate to non-planar
pentagon functions, described by a 31-letter symbol alphabet. We express the
final result for the amplitude in terms of uniform weight four symbols,
multiplied by a small set of rational factors. The amplitude satisfies the
expected factorization properties when one external graviton becomes soft, and
when two external gravitons become collinear. We verify that the soft
divergences of the amplitude exponentiate, and extract the finite remainder
function. The latter depends on fewer rational factors, and is independent of
one of the symbol letters. By analyzing identities involving rational factors
and symbols we find a remarkably compact representation in terms of a single
seed function, summed over all permutations of external particles. Finally, we
work out the multi-Regge limit, and present explicitly the leading logarithmic
terms in the limit. The full symbol of the IR-subtracted hard function is
provided as an ancillary file.Comment: 22 pages, 1 figure, 8 ancillary file
How Do Maternal Subclinical Symptoms Influence Infant Motor Development during the First Year of Life?
An unavoidable reciprocal influence characterizes the mother-child dyad. Within this relationship, the presence of depression, somatization, hostility, paranoid ideation, and interpersonal sensitivity symptoms at a subclinical level and their possible input on infant motor competences has not been yet considered. Bearing in mind that motor abilities represent not only an indicator of the infant\u2019s health-status, but also the principal field to infer his/her needs, feelings and intentions, in this study the quality of infants\u2019 movements were assessed and analyzed in relationship with the maternal attitudes. The aim of this research was to investigate if/how maternal symptomatology may pilot infant\u2019s motor development during his/her first year of life by observing the characteristics of motor development in infants aged 0\u201311 months. Participants included 123 mothers and their infants (0\u201311 months-old). Mothers\u2019 symptomatology was screened with the Symptom Checklist-90-Revised (SCL-90-R), while infants were tested with the Peabody Developmental Motor Scale-Second Edition. All dyads belonged to a non-clinical population, however, on the basis of SCL-90-R scores, the mothers\u2019 sample was divided into two groups: normative and subclinical. Descriptive, t-test, correlational analysis between PDMS-2 scores and SCL-90-R results are reported, as well as regression models results. Both positive and negative correlations were found between maternal perceived symptomatology, Somatization (SOM), Interpersonal Sensitivity (IS), Depression (DEP), Hostility (HOS), and Paranoid Ideation (PAR) and infants\u2019 motor abilities. These results were further verified by applying regression models to predict the infant\u2019s motor outcomes on the basis of babies\u2019 age and maternal status. The presence of positive symptoms in the SCL-90-R questionnaire (subclinical group) predicted good visual-motor integration and stationary competences in the babies. In particular, depressive and hostility feelings in mothers seemed to induce an infant motor behavior characterized by a major control of the environmental space. When mothers perceived a higher level of hostility and somatization, their babies showed difficulties in sharing action space, such as required in the development of stationary positions and grasping abilities. In a completely different way, when infants can rely on a mother with low-perceived symptoms (normative group) his/her motor performances develop with a higher degree of freedom/independence. These findings suggest, for the first time, that even in a non- clinical sample, mother\u2019s perceived-symptoms can produce important consequences not in infant motor development as a whole, but in some specific areas, contributing to shape the infant\u2019s motor ability and his/her capability to act in the world
Nutritional management of individuals with Huntington’s disease: nutritional guidelines
The delivery of good nutritional care is a fundamental element of the management of individuals with Huntington’s disease and all patients with Huntington’s disease will, at some time, need dietary intervention because of the sequela of the disease; yet there are no European nutritional guidelines. The European Huntington’s Disease Network Standards of Care Dietitians Group has brought together expert dietitians from across Europe to produce nutritional guidelines to improve the nutritional management of individuals with Huntington’s disease. The guidelines were developed to promote optimal nutritional screening, assessment and management of individuals throughout all stages of the disease, with the aim of improving the standard of nutritional care delivered. Literature was systematically searched in an attempt to ensure that the recommendations are based on sound evidence and where evidence is lacking, specific guidance is based on consensus expert dietetic opinion. The provision of nutritional care varies widely between countries. Implementation of these nutritional guidelines across Europe should improve the quality of nutritional care delivered to individuals with Huntington’s disease
A model of dispersive transport across sharp interfaces between porous materials
Recent laboratory experiments on solute migration in composite porous columns
have shown an asymmetry in the solute arrival time upon reversal of the flow
direction, which is not explained by current paradigms of transport. In this
work, we propose a definition for the solute flux across sharp interfaces and
explore the underlying microscopic particle dynamics by applying Monte Carlo
simulation. Our results are consistent with previous experimental findings and
explain the observed transport asymmetry. An interpretation of the proposed
physical mechanism in terms of a flux rectification is also provided. The
approach is quite general and can be extended to other situations involving
transport across sharp interfaces.Comment: 4 pages, 4 figure
Do Canadian Consumers Have Concerns about Genetically Modified Animal Feeds?
This article analyzes responses from a 2008 survey of Canadian meat consumers about concerns regarding genetically modified (GM) feed used in livestock meat production. Approximately 50% of the sampled consumers express relatively high levels of concern about GM feeds. Based on the results from an ordered probit model that relates respondents' ratings of concern to their demographic characteristics, residents of Quebec and British Columbia tend to be more concerned than those in other locations. Respondents who express more trust in food industry institutions and show more confidence in buying beef and chicken tend to express less concern about GM animal feed. Other demographic characteristics and the household's levels of expenditures on different types of meat are not found to have an effect on expressed concerns with respect to GM-fed animals
Perceived maternal symptomatology and its influence on newborn’s motor development. Study on non-clinical mother-infant (1-11 months) dyads.
Introduction: Newborn’s first approach to the world takes place in the relationship with his/her mother. He/she builds his/her-own experiences from mother's repertoire of facial expressions, voices, gestures. Contemporarily, the process of becoming mother entails a wide range of changes, which may lead to psychopathology conditions, among which post-partum depression is the most common. This disease is known to negatively influence maternal abilities and produce feelings of greater struggle in caring the infant, sense of guilty and poor self-efficacy. Motor development represents the principal field of observation in helping to infer infant's needs, feelings and intentions. Its investigation may be a powerful means to understand the influence of maternal attitudes (e.g. depressive-symptoms) on infant motor-development.
Aims of the study: The main aim of this research was to investigate the characteristics of motor- development in infants aged 1-11 months, and if/how maternal depressive-symptomatology may influence infant's motor-development during his/her first year of life.
Material&Methods: Data were collected within the wider Italian-validation-project of the Peabody Developmental Motor Scale-II (PDMS-2). Participants included 123 infants (1-11 months old) with their mothers. Infants were tested with PDMS-2 and mothers’ symptomatology was screened with SCL-90-TR and CES-D. All dyads belong to non-clinical population. We calculated correlational- and regression-analysis between PDMS-2,SCL-90 and CES-D.
Results: The best predictor of infants’ motor-performance is the age in months. Perceived maternal somatization negatively predicted infants’ Fine-Motor-scores. On the contrary, positive
correlations were found between depressive perceived
symptoms, InterpersonalSensitivity, Hostility and Paranoid Ideation and infants Gross-
Motor abilities, especially Locomotion.
Conclusions: Results suggest that mother's perceived symptoms influence the ability of the infant to move trough the space, while perceived levels of somatization negatively predict his/her fine- motor development. Age-in-months is the most accurate predictor of motor-performance. Further analyses are needed to better understand relationship between maternal-symptomatology and infant motor-skills
A nonlinear random walk approach to concentration-dependent contaminant transport in porous media
We propose a nonlinear random walk model to describe the dynamics of dense
contaminant plumes in porous media. A coupling between concentration and
velocity fields is found, so that transport displays non-Fickian features. The
qualitative behavior of the pollutant spatial profiles and moments is explored
with the help of Monte Carlo simulation, within a Continuous Time Random Walk
approach. Model outcomes are then compared with experimental measurements of
variable-density contaminant transport in homogeneous and saturated vertical
columns.Comment: 8 pages, 9 figure
Cauchy's formulas for random walks in bounded domains
Cauchy's formula was originally established for random straight paths
crossing a body and basically relates the average
chord length through to the ratio between the volume and the surface of the
body itself. The original statement was later extended in the context of
transport theory so as to cover the stochastic paths of Pearson random walks
with exponentially distributed flight lengths traversing a bounded domain. Some
heuristic arguments suggest that Cauchy's formula may also hold true for
Pearson random walks with arbitrarily distributed flight lengths. For such a
broad class of stochastic processes, we rigorously derive a generalized
Cauchy's formula for the average length travelled by the walkers in the body,
and show that this quantity depends indeed only on the ratio between the volume
and the surface, provided that some constraints are imposed on the entrance
step of the walker in . Similar results are obtained also for the average
number of collisions performed by the walker in , and an extension to
absorbing media is discussed.Comment: 12 pages, 6 figure
La formación permanente del profesorado en Cataluña. Análisis de los referentes legales
Este artículo tiene como objetivo describir y analizar la evolución de la formación permanente del profesorado en Cataluña, tomando como eje de análisis los referentes legales publicados en las últimas décadas. El texto hace una revisión de los Planes Marco de Formación Permanente promulgados desde 1989 hasta la actualidad y analiza detenidamente los cambios que se han producido en algunas de las dimensiones más importantes de la formación permanente del profesorado. MÉTODO. Para ello hemos recurrido a un enfoque cualitativo de investigación y la estrategia fundamental de recogida de datos ha sido el análisis documental de los referentes legales mencionados y de otros documentos adicionales. RESULTADOS Y DISCUSIÓN. Los resultados de este estudio se dirigen a resituar los referentes legales en los contextos educativos y sociales en los que se promulgaron, a la vez que mostrar los puntos comunes y divergentes existentes entre ellos y una justificación de los cambios y evolución de la propia formación docente. Los hallazgos de esta investigación ponen de manifiesto la existencia de una elevada preocupación por la formación permanente del profesorado en territorio catalán, tangible por la profusión de trabajos existentes sobre la temática. A su vez, el estudio señala aquellos aspectos dilemáticos que, en la actualidad, requieren de una atención preferente
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