1,315 research outputs found
The Dialectics of Parenting: Changes in the Interplay of Maternal Behaviors during Early and Middle Childhood
Parent and child relationships continuously evolve, part of an ongoing dialectic that derives from developmental changes in both parent and child. The focus of this study is on changes in the strength of association among four types of parenting behaviors considered important for children’s development: supportive presence, respect for autonomy, stimulation, and hostility. Mother–child interaction was observed for 1229 parent–child dyads at 36 months, 54 months, 1st grade, 3rd grade, and 5th grade using similar observational paradigms. The association between respect for autonomy and supportive presence was strong at age three and continued to be strong over time. The association between respect for autonomy and stimulation was modest but also showed little change from age three to 5th grade. Respect for autonomy was negatively associated with maternal hostility, but the relation was complex. It was stronger at 54 months than 36 months but then became weaker through time. Supportive presence showed a moderate relation with stimulation at age 3 but the association became weaker over time. Supportive presence showed an expected negative association with hostility, a relation that changed little over time. The relation between hostility and stimulation also became weaker over time. In effect, there appears to be a shifting pattern of relations between maternal behaviors during early and middle childhood, one that reflects an evolving dialectic in the mother–child relationship
Quantification of microbubble concentration through x-ray phase contrast imaging
The use of microbubbles as a contrast agent for x-ray phase contrast imaging could both transform x-ray imaging into a “functional” modality and enable much needed monitoring of targeted drug delivery. To realize these benefits, it is essential to be able to quantify bubble concentration in a given tissue volume. We developed and validated a model that enables this to be achieved not only for phase-retrieved images obtained by processing multiple frames but also on “single-shot” images, a likely necessity in in-vivo implementations. Our experimental validation was based on analyzer-based imaging, but extension to other phase-based modalities is straightforward
Associations of sedentary behaviour, physical activity, blood pressure and anthropometric measures with cardiorespiratory fitness in children with cerebral palsy
Background - Children with cerebral palsy (CP) have poor cardiorespiratory fitness in comparison to their peers with typical development, which may be due to low levels of physical activity. Poor cardiorespiratory fitness may contribute to increased cardiometabolic risk. Purpose - The aim of this study was to determine the association between sedentary behaviour, physical activity and cardiorespiratory fitness in children with CP. An objective was to determine the association between cardiorespiratory fitness, anthropometric measures and blood pressure in children with CP. Methods- This study included 55 ambulatory children with CP [mean (SD) age 11.3 (0.2) yr, range 6-17 yr; Gross Motor Function Classification System (GMFCS) levels I and II]. Anthropometric measures (BMI, waist circumference and waist-height ratio) and blood pressure were taken. Cardiorespiratory fitness was measured using a 10 m shuttle run test. Children were classified as low, middle and high fitness according to level achieved on the test using reference curves. Physical activity was measured by accelerometry over 7 days. In addition to total activity, time in sedentary behaviour and light, moderate, vigorous, and sustained moderate-to-vigorous activity (≥10 min bouts) were calculated. Results - Multiple regression analyses revealed that vigorous activity (β = 0.339, p<0.01), sustained moderate-to-vigorous activity (β = 0.250, p<0.05) and total activity (β = 0.238, p<0.05) were associated with level achieved on the shuttle run test after adjustment for age, sex and GMFCS level. Children with high fitness spent more time in vigorous activity than children with middle fitness (p<0.05). Shuttle run test level was negatively associated with BMI (r2 = -0.451, p<0.01), waist circumference (r2 = -0.560, p<0.001), waist-height ratio (r2 = -0.560, p<0.001) and systolic blood pressure (r2 = -0.306, p<0.05) after adjustment for age, sex and GMFCS level. Conclusions - Participation in physical activity, particularly at a vigorous intensity, is associated with high cardiorespiratory fitness in children with CP. Low cardiorespiratory fitness is associated with increased cardiometabolic risk
Quasi-Normal Modes of Stars and Black Holes
Perturbations of stars and black holes have been one of the main topics of
relativistic astrophysics for the last few decades. They are of particular
importance today, because of their relevance to gravitational wave astronomy.
In this review we present the theory of quasi-normal modes of compact objects
from both the mathematical and astrophysical points of view. The discussion
includes perturbations of black holes (Schwarzschild, Reissner-Nordstr\"om,
Kerr and Kerr-Newman) and relativistic stars (non-rotating and
slowly-rotating). The properties of the various families of quasi-normal modes
are described, and numerical techniques for calculating quasi-normal modes
reviewed. The successes, as well as the limits, of perturbation theory are
presented, and its role in the emerging era of numerical relativity and
supercomputers is discussed.Comment: 74 pages, 7 figures, Review article for "Living Reviews in
Relativity
Understanding psychiatric institutionalization: a conceptual review
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Saturn satellites as seen by Cassini Mission
In this paper we will summarize some of the most important results of the
Cassini mission concerning the satellites of Saturn. Given the long duration of
the mission, the complexity of the payload onboard the Cassini Orbiter and the
amount of data gathered on the satellites of Saturn, it would be impossible to
describe all the new discoveries made, therefore we will describe only some
selected, paramount examples showing how Cassini's data confirmed and extended
ground-based observations. In particular we will describe the achievements
obtained for the satellites Phoebe, Enceladus and Titan. We will also put these
examples in the perspective of the overall evolution of the system, stressing
out why the selected satellites are representative of the overall evolution of
the Saturn system.Comment: 34 pages, 10 figures, to appear on the special issue of Earth, Moon
and Planets for the Elba worksho
Extragalactic Radio Continuum Surveys and the Transformation of Radio Astronomy
Next-generation radio surveys are about to transform radio astronomy by
discovering and studying tens of millions of previously unknown radio sources.
These surveys will provide new insights to understand the evolution of
galaxies, measuring the evolution of the cosmic star formation rate, and
rivalling traditional techniques in the measurement of fundamental cosmological
parameters. By observing a new volume of observational parameter space, they
are also likely to discover unexpected new phenomena. This review traces the
evolution of extragalactic radio continuum surveys from the earliest days of
radio astronomy to the present, and identifies the challenges that must be
overcome to achieve this transformational change.Comment: To be published in Nature Astronomy 18 Sept 201
Three little pieces for computer and relativity
Numerical relativity has made big strides over the last decade. A number of
problems that have plagued the field for years have now been mostly solved.
This progress has transformed numerical relativity into a powerful tool to
explore fundamental problems in physics and astrophysics, and I present here
three representative examples. These "three little pieces" reflect a personal
choice and describe work that I am particularly familiar with. However, many
more examples could be made.Comment: 42 pages, 11 figures. Plenary talk at "Relativity and Gravitation:
100 Years after Einstein in Prague", June 25 - 29, 2012, Prague, Czech
Republic. To appear in the Proceedings (Edition Open Access). Collects
results appeared in journal articles [72,73, 122-124
Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes.
A considerable body of research indicates that mammary gland branching morphogenesis is dependent, in part, on the extracellular matrix (ECM), ECM-receptors, such as integrins and other ECM receptors, and ECM-degrading enzymes, including matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). There is some evidence that these ECM cues affect one or more of the following processes: cell survival, polarity, proliferation, differentiation, adhesion, and migration. Both three-dimensional culture models and genetic manipulations of the mouse mammary gland have been used to study the signaling pathways that affect these processes. However, the precise mechanisms of ECM-directed mammary morphogenesis are not well understood. Mammary morphogenesis involves epithelial 'invasion' of adipose tissue, a process akin to invasion by breast cancer cells, although the former is a highly regulated developmental process. How these morphogenic pathways are integrated in the normal gland and how they become dysregulated and subverted in the progression of breast cancer also remain largely unanswered questions
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