145 research outputs found
Half-a-Century of the »Körmend Growth Study«
The authors give a sketch about the „Körmend Growth Study« which is series of
cross-sectional growth studies, carried out in Körmend, a small town in Western Hungary.
The first investigation was carried out in 1958 (K-58) and it has been repeated every
ten years (K-68, K-78, K-88, and K-98). All 3-18 year-old healthy boys and girls in nurseries
and schools in Körmend were involved in the study. Twenty-three body measurements
were taken. This paper focuses on changes in height, weight, and BMI. Means of
these two body measurements show an increase from time to time (as a phenomenon of
positive secular trend), however, the secular trend for increasing height and weight is
declining. BMI follows a similar pattern
Stationary probability density of stochastic search processes in global optimization
A method for the construction of approximate analytical expressions for the
stationary marginal densities of general stochastic search processes is
proposed. By the marginal densities, regions of the search space that with high
probability contain the global optima can be readily defined. The density
estimation procedure involves a controlled number of linear operations, with a
computational cost per iteration that grows linearly with problem size
Food and beverage intakes according to physical activity levels in European children: The IDEFICS (Identification and prevention of Dietary and lifestyle induced health EFfects in Children and infantS) study
Objective Physical activity (PA) levels and dietary habits are considered some of the most important factors associated with obesity. The present study aimed to examine the association between PA level and food and beverage consumption in European children (2-10 years old).Design/Setting/Subjects A sample of 7229 children (49·0 % girls) from eight European countries participating in the IDEFICS (Identification and prevention of Dietary and lifestyle induced health EFfects In Children and infantS) study was included. Moderate-to-vigorous PA (MVPA) was assessed objectively with accelerometers. FFQ was used to register dietary habits. ANCOVA and binary logistic regression were applied.Results Boys who spent less time in MVPA reported lower consumption of vegetables, fruits, cereals, yoghurt, milk, bread, pasta, candies and sugar-sweetened beverages (SSB) than boys who spent more time in MVPA (P<0·05). Moreover, boys who spent less time in MVPA were more likely to consume fast foods and water than those in the highest MVPA tertile (P<0·05). Girls who spent less time in MVPA reported lower consumption frequencies of vegetables, pasta, bread, yoghurt, candies, jam/honey and SSB than girls in the highest MVPA tertile (P<0·05). Also, girls in the lowest MVPA tertile were more likely to consume fast foods and water than those with high levels of MVPA (P<0·05).Conclusions Food intake among European children varied with different levels of daily MVPA. Low time spent in MVPA was associated with lowest consumption of both high- and low-energy-dense foods and high fast-food consumption
Monotonicity of Fitness Landscapes and Mutation Rate Control
A common view in evolutionary biology is that mutation rates are minimised.
However, studies in combinatorial optimisation and search have shown a clear
advantage of using variable mutation rates as a control parameter to optimise
the performance of evolutionary algorithms. Much biological theory in this area
is based on Ronald Fisher's work, who used Euclidean geometry to study the
relation between mutation size and expected fitness of the offspring in
infinite phenotypic spaces. Here we reconsider this theory based on the
alternative geometry of discrete and finite spaces of DNA sequences. First, we
consider the geometric case of fitness being isomorphic to distance from an
optimum, and show how problems of optimal mutation rate control can be solved
exactly or approximately depending on additional constraints of the problem.
Then we consider the general case of fitness communicating only partial
information about the distance. We define weak monotonicity of fitness
landscapes and prove that this property holds in all landscapes that are
continuous and open at the optimum. This theoretical result motivates our
hypothesis that optimal mutation rate functions in such landscapes will
increase when fitness decreases in some neighbourhood of an optimum, resembling
the control functions derived in the geometric case. We test this hypothesis
experimentally by analysing approximately optimal mutation rate control
functions in 115 complete landscapes of binding scores between DNA sequences
and transcription factors. Our findings support the hypothesis and find that
the increase of mutation rate is more rapid in landscapes that are less
monotonic (more rugged). We discuss the relevance of these findings to living
organisms
A Profile Likelihood Analysis of the Constrained MSSM with Genetic Algorithms
The Constrained Minimal Supersymmetric Standard Model (CMSSM) is one of the
simplest and most widely-studied supersymmetric extensions to the standard
model of particle physics. Nevertheless, current data do not sufficiently
constrain the model parameters in a way completely independent of priors,
statistical measures and scanning techniques. We present a new technique for
scanning supersymmetric parameter spaces, optimised for frequentist profile
likelihood analyses and based on Genetic Algorithms. We apply this technique to
the CMSSM, taking into account existing collider and cosmological data in our
global fit. We compare our method to the MultiNest algorithm, an efficient
Bayesian technique, paying particular attention to the best-fit points and
implications for particle masses at the LHC and dark matter searches. Our
global best-fit point lies in the focus point region. We find many
high-likelihood points in both the stau co-annihilation and focus point
regions, including a previously neglected section of the co-annihilation region
at large m_0. We show that there are many high-likelihood points in the CMSSM
parameter space commonly missed by existing scanning techniques, especially at
high masses. This has a significant influence on the derived confidence regions
for parameters and observables, and can dramatically change the entire
statistical inference of such scans.Comment: 47 pages, 8 figures; Fig. 8, Table 7 and more discussions added to
Sec. 3.4.2 in response to referee's comments; accepted for publication in
JHE
Results and Limits of Time Division Multiplexing for the BICEP Array High Frequency Receivers
Time-Division Multiplexing is the readout architecture of choice for many
ground and space experiments, as it is a very mature technology with proven
outstanding low-frequency noise stability, which represents a central challenge
in multiplexing. Once fully populated, each of the two BICEP Array high
frequency receivers, observing at 150GHz and 220/270GHz, will have 7776 TES
detectors tiled on the focal plane. The constraints set by these two receivers
required a redesign of the warm readout electronics. The new version of the
standard Multi Channel Electronics, developed and built at the University of
British Columbia, is presented here for the first time. BICEP Array operates
Time Division Multiplexing readout technology to the limits of its capabilities
in terms of multiplexing rate, noise and crosstalk, and applies them in
rigorously demanding scientific application requiring extreme noise performance
and systematic error control. Future experiments like CMB-S4 plan to use TES
bolometers with Time Division/SQUID-based readout for an even larger number of
detectors.Comment: 10 pages, 7 figures, Submitted to Journal of Low Temperature Physic
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