1,409 research outputs found
Parallel Metropolis chains with cooperative adaptation
Monte Carlo methods, such as Markov chain Monte Carlo (MCMC) algorithms, have
become very popular in signal processing over the last years. In this work, we
introduce a novel MCMC scheme where parallel MCMC chains interact, adapting
cooperatively the parameters of their proposal functions. Furthermore, the
novel algorithm distributes the computational effort adaptively, rewarding the
chains which are providing better performance and, possibly even stopping other
ones. These extinct chains can be reactivated if the algorithm considers
necessary. Numerical simulations shows the benefits of the novel scheme
Orthogonal parallel MCMC methods for sampling and optimization
Monte Carlo (MC) methods are widely used for Bayesian inference and
optimization in statistics, signal processing and machine learning. A
well-known class of MC methods are Markov Chain Monte Carlo (MCMC) algorithms.
In order to foster better exploration of the state space, specially in
high-dimensional applications, several schemes employing multiple parallel MCMC
chains have been recently introduced. In this work, we describe a novel
parallel interacting MCMC scheme, called {\it orthogonal MCMC} (O-MCMC), where
a set of "vertical" parallel MCMC chains share information using some
"horizontal" MCMC techniques working on the entire population of current
states. More specifically, the vertical chains are led by random-walk
proposals, whereas the horizontal MCMC techniques employ independent proposals,
thus allowing an efficient combination of global exploration and local
approximation. The interaction is contained in these horizontal iterations.
Within the analysis of different implementations of O-MCMC, novel schemes in
order to reduce the overall computational cost of parallel multiple try
Metropolis (MTM) chains are also presented. Furthermore, a modified version of
O-MCMC for optimization is provided by considering parallel simulated annealing
(SA) algorithms. Numerical results show the advantages of the proposed sampling
scheme in terms of efficiency in the estimation, as well as robustness in terms
of independence with respect to initial values and the choice of the
parameters
Zastosowanie programu gwarancji dla zdrowia jamy ustnej w opiece nad kobietą w ciąży w rodzinnym centrum zdrowia w Concepción, Chile, w latach 2014–2015
Indexación: Scopus.Background. Oral health plays a crucial role in general health, quality of life and well-being of pregnant women and their newborns. In Chile, pregnant women have dental care guaranteed by law. However, due to the lack of previous epidemiological studies on the benefits of this guarantee, it is necessary to describe this situation and evaluate the need to change the methods of providing dental services. Objectives. The objective of this study was to describe the pattern of providing dental benefits resulting from the Explicit Health Guarantee – Integral Oral Health in Pregnant Women (GES-SOIE) program to pregnant women attending the Juan Soto Fernández Family Health Center, Concepción, Chile, in 2014–2015. Material and methods. A cross-sectional study of the electronic dental records of patients admitted to GES-SOIE was conducted. The variables studied were sociodemographic data, dental chair hours, non-attendance, treatment completion, and the type of referral to secondary healthcare (SHC). Results. Of 233 pregnant women, 65.2% were registered for non-attendance, 21.2% required referral to SHC and 76.4% completed their treatment. When performing logistic regression, it was found that for each non-attendance the chance of not completing the treatment increased 1.4 times. Conclusions. The level of non-attendance and opting out of the treatment in pregnant women is high, which hinders the proper functioning and effectiveness of GES-SOIE. © 2018 by Wroclaw Medical University and Polish Dental Society.http://www.dmp.umed.wroc.pl/en/article/2018/55/2/179
Three-dimensional morphology and gene expression in the Drosophila blastoderm at cellular resolution II: dynamics.
BackgroundTo accurately describe gene expression and computationally model animal transcriptional networks, it is essential to determine the changing locations of cells in developing embryos.ResultsUsing automated image analysis methods, we provide the first quantitative description of temporal changes in morphology and gene expression at cellular resolution in whole embryos, using the Drosophila blastoderm as a model. Analyses based on both fixed and live embryos reveal complex, previously undetected three-dimensional changes in nuclear density patterns caused by nuclear movements prior to gastrulation. Gene expression patterns move, in part, with these changes in morphology, but additional spatial shifts in expression patterns are also seen, supporting a previously proposed model of pattern dynamics based on the induction and inhibition of gene expression. We show that mutations that disrupt either the anterior/posterior (a/p) or the dorsal/ventral (d/v) transcriptional cascades alter morphology and gene expression along both the a/p and d/v axes in a way suggesting that these two patterning systems interact via both transcriptional and morphological mechanisms.ConclusionOur work establishes a new strategy for measuring temporal changes in the locations of cells and gene expression patterns that uses fixed cell material and computational modeling. It also provides a coordinate framework for the blastoderm embryo that will allow increasingly accurate spatio-temporal modeling of both the transcriptional control network and morphogenesis
Comparing UK and 20 Western countries' efficiency in reducing adult (55-74) cancer and total mortality rates 1989-2010: Cause for cautious celebration? A population-based study.
OBJECTIVE: Every Western nation expends vast sums on health, especially for cancer; thus, the question is how efficient is the UK in reducing adult (55-74) cancer mortality rates and total mortality rates (TMR) compared to the other Western nations in the context of economic-input to health, the percentage of Gross-Domestic-Product-expenditure-on-Health. DESIGN: WHO mortality rates for baseline 3 years 1989-1991 and 2008-2010 were analysed, and confidence intervals determine any significant differences between the UK and other countries in reducing the mortalities. Efficiency ratios are calculated by dividing reduced mortality over the period by the average % of national income. SETTING: Twenty-one similar socio-economic Western countries. PARTICIPANTS: The 21 countries' general population. MAIN OUTCOME MEASURES: Cancer mortality rates, total mortality rates Gross Domestic Product and Efficiency Ratios. RESULTS: Economic Input: In 1980, UK national income was 5.6% and the European average was 7.1%. By 2010, UK national income was 9.4% being equal 17th of 21 averaging 7.1% over the period. Europe's 1980-2010 average of 8.4% yields a UK to Europe ratio of 1:1.18. Clinical output 1989-2010: UK Cancer Mortality Rates was the sixth highest, but equal sixth biggest fall, significantly greater than 14 other countries. UK Total Mortality Rates was the fifth highest but third biggest decline, significantly greater than 17 countries. UK's cancer Efficiency Ratios is largest at 1:301 and second biggest for Total Mortality Rates at 1.1341; the USA ratios were 1:152 and 1:525, respectively. CONCLUSIONS: UK reduced mortalities indicate that the NHS achieves proportionally more with relatively less, but UK needs to match European average Gross-Domestic-Product-expenditure-on-Health to meet future challenges
Narrativa contemporánea de aventuras y educación literaria en la adolescencia
Al artÃculo pretende poner de manifiesto la
situación actual de la narrativa juvenil contemporánea
española de viajes y aventuras, asà como su
puesta en valor en la formación lectora de los estudiantes
de Secundaria. El análisis literario de estas
novelas y de los antecedentes de este subgénero
narrativo, y el establecimiento de un canon literario
actualizado nos proporcionan las bases para definir
una poética de la novela de aventuras
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