72,523 research outputs found
Socio-economic determinants of selected dietary indicators in British pre-school children
Objectives: To assess the proportion of pre-school children meeting reference nutrient intakes (RNIs) and recommendations for daily intakes of iron, zinc, vitamins C and A, and energy from non-milk extrinsic sugars. To assess whether meeting these five dietary requirements was related to a series of socio-economic variables.Design: Secondary analysis of data on daily consumption of foods and drinks from the National Diet and Nutrition Survey (NDNS) of children aged 1.5-4.5 years based on 4-day weighed intakes.Subjects: One thousand six hundred and seventy-five British pre-school children aged 1.5-4.5 years in 1993.Results: Only 1% of children met all five RNIs/recommendations examined; 76% met only two or fewer. Very few children met the recommendations for intakes of zinc (aged over four years) and non-milk extrinsic sugars (all ages). The number of RNIs/ recommendations met was related to measures of socio-economic class. Children from families in Scotland and the North of England, who had a manual head of household and whose mothers had fewest qualifications, met the least number of RNIs/recommendations.Conclusions: Very few pre-school children have diets that meet all the RNIs and recommendations for iron, zinc, vitamins C and A, and energy from non-milk extrinsic sugars. Dietary adequacy with respect to these five parameters is related to socio-economic factors. The findings emphasise the need for a range of public health policies that focus upon the social and economic determinants of food choice within families
Around Kolmogorov complexity: basic notions and results
Algorithmic information theory studies description complexity and randomness
and is now a well known field of theoretical computer science and mathematical
logic. There are several textbooks and monographs devoted to this theory where
one can find the detailed exposition of many difficult results as well as
historical references. However, it seems that a short survey of its basic
notions and main results relating these notions to each other, is missing.
This report attempts to fill this gap and covers the basic notions of
algorithmic information theory: Kolmogorov complexity (plain, conditional,
prefix), Solomonoff universal a priori probability, notions of randomness
(Martin-L\"of randomness, Mises--Church randomness), effective Hausdorff
dimension. We prove their basic properties (symmetry of information, connection
between a priori probability and prefix complexity, criterion of randomness in
terms of complexity, complexity characterization for effective dimension) and
show some applications (incompressibility method in computational complexity
theory, incompleteness theorems). It is based on the lecture notes of a course
at Uppsala University given by the author
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Avoiding chromosome pathology when replication forks collide
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2013 Macmillan Publishers Limited.Chromosome duplication normally initiates through the assembly of replication fork complexes at defined origins1, 2. DNA synthesis by any one fork is thought to cease when it meets another travelling in the opposite direction, at which stage the replication machinery may simply dissociate before the nascent strands are finally ligated. But what actually happens is not clear. Here we present evidence consistent with the idea that every fork collision has the potential to threaten genomic integrity. In Escherichia coli this threat is kept at bay by RecG DNA translocase3 and by single-strand DNA exonucleases. Without RecG, replication initiates where forks meet through a replisome assembly mechanism normally associated with fork repair, replication restart and recombination4, 5, establishing new forks with the potential to sustain cell growth and division without an active origin. This potential is realized when roadblocks to fork progression are reduced or eliminated. It relies on the chromosome being circular, reinforcing the idea that replication initiation is triggered repeatedly by fork collision. The results reported raise the question of whether replication fork collisions have pathogenic potential for organisms that exploit several origins to replicate each chromosome.THe MRC, the Leverhulme Trust, and the BBSRC
Recent glacial recession in the Rwenzori Mountains of East Africa due to rising air temperature
Based on field surveys and analyses of optical spaceborne images (LandSat5, LandSat7), we report recent decline in the areal extent of glaciers in the Rwenzori Mountains of East Africa from 2.01 +/- 0.56 km(2) in 1987 to 0.96 +/- 0.34 km(2) in 2003. The spatially uniform loss of glacial cover at lower elevations together with meteorological trends derived from both station and reanalysis data, indicate that increased air temperature is the main driver. Clear trends toward increased air temperatures over the last four decades of similar to 0.5 degrees C per decade exist without significant changes in annual precipitation. Extrapolation of trends in glacial recession since 1906 suggests that glaciers in the Rwenzori Mountains will disappear within the next two decades
Reply to comment by T. Molg et al. on "Recent glacial recession in the Rwenzori Mountains of East Africa due to rising air temperature"
Lovelock gravity from entropic force
In this paper, we first generalize the formulation of entropic gravity to
(n+1)-dimensional spacetime. Then, we propose an entropic origin for
Gauss-Bonnet gravity and more general Lovelock gravity in arbitrary dimensions.
As a result, we are able to derive Newton's law of gravitation as well as the
corresponding Friedmann equations in these gravity theories. This procedure
naturally leads to a derivation of the higher dimensional gravitational
coupling constant of Friedmann/Einstein equation which is in complete agreement
with the results obtained by comparing the weak field limit of Einstein
equation with Poisson equation in higher dimensions. Our study shows that the
approach presented here is powerful enough to derive the gravitational field
equations in any gravity theory. PACS: 04.20.Cv, 04.50.-h, 04.70.Dy.Comment: 10 pages, new versio
Pneumothorax and Pneumomediastinum in a Sputum Positive Tuberculosis Patient: The Continuous Diaphragm Sign
Secondary pneumothorax is a very common medical emergency. At times it is associated with pneumomediastinum, which could be fatal at times if not identified. We present a case of a 11 years old sputum positive child who presented with both these conditions and was diagnosed on chest x ray
Degree spectra for transcendence in fields
We show that for both the unary relation of transcendence and the finitary
relation of algebraic independence on a field, the degree spectra of these
relations may consist of any single computably enumerable Turing degree, or of
those c.e. degrees above an arbitrary fixed degree. In other
cases, these spectra may be characterized by the ability to enumerate an
arbitrary set. This is the first proof that a computable field can
fail to have a computable copy with a computable transcendence basis
Parameterized Algorithms for Graph Partitioning Problems
We study a broad class of graph partitioning problems, where each problem is
specified by a graph , and parameters and . We seek a subset
of size , such that is at most
(or at least) , where are constants
defining the problem, and are the cardinalities of the edge sets
having both endpoints, and exactly one endpoint, in , respectively. This
class of fixed cardinality graph partitioning problems (FGPP) encompasses Max
-Cut, Min -Vertex Cover, -Densest Subgraph, and -Sparsest
Subgraph.
Our main result is an algorithm for any problem in
this class, where is the maximum degree in the input graph.
This resolves an open question posed by Bonnet et al. [IPEC 2013]. We obtain
faster algorithms for certain subclasses of FGPPs, parameterized by , or by
. In particular, we give an time algorithm for Max
-Cut, thus improving significantly the best known time
algorithm
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