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Garmendia, M. L., Mondschein, S., Montiel, B., & Kusanovic, J. P. (2021). Trends and predictors of birth weight in Chilean children. Public Health, 193, 61–68.
Abstract: Objectives: Birth weight is an important public health indicator that reflects fetal health conditions and predicts future health. Identifying the most important factors related to birth weight would help defining preventive health strategies for both mothers and children. The objectives of this study are i. to describe, using a large birth database from a Chilean hospital, the trend of birth weight during 2002-2015, and ii. to determine factors during prenatal care associated with low and high birth weight.
Study design: This study is a secondary analysis of all single birth records at a Chilean Hospital in the southeast district of Santiago, Chile, during 2002-2015 (N = 78,931).
Methods: Sociodemographic information, clinical and obstetric history, lifestyle, and anthropometric variables were evaluated as potential predictors. Birth weight was categorized into five groups as per percentiles of weight as per gestational age. Data were extracted from clinical records. We used classification and regression tree methodology and logistic regression.
Results: The average birth weight for the period was 3316 g (SD 566), with little variation across time. Preterm births increased from 7% in 2002 to 10% in 2015, and births >40 weeks decreased from 10.7% in 2002 to 4.4% in 2015. The percentages of small and large for gestational age changed from 10.9% and 12.7% in 2002 to 9.9% and 13.9% in 2015, respectively. The predictors included in the optimal tree were body mass index, gestational weight gain, pre-eclampsia, and gestational diabetes. We found that women with a pregestational body mass index <28 kg/m(2), gestational weight gain <17 kg, and pre-eclampsia had a probability of 41% of having a small for gestational age neonate. Conversely, women with a body mass index similar to 28 kg/m(2), gestational weight gain similar to 17 kg, and gestational diabetes had a probability of 44% of having a large for gestational age neonate.
Conclusions: This study showed that the most important variables explaining birth weight are those related to maternal nutritional status. Thus, the strategies to promote a normal birth weight should aim for a normal maternal weight at the beginning of pregnancy, gestational weight gain within the recommendations, and prevention of gestational diabetes and pre-eclampsia. (C) 2021 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.
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Girard, A., Gago, E. J., Ordonez, J., & Muneer, T. (2016). Spain's energy outlook: A review of PV potential and energy export. Renew. Energy, 86, 703–715.
Abstract: Spain must reduce its energy consumption by 23% and achieve 100% renewable energy in electricity generation by 2030. This paper presents the current energy scenario en Spain, and the outlooks for different renewable options, with special focus on photovoltaic (PV) solar energy. In 2012, Spain was the number two European country in terms of installed rewnewable energy power. Solar PV technology has the potential to meet Spain's future energy demand and its associated environmental challenges. This paper gives a review of solar energy economy at global scale for both PV and thermal power technologies. The Spanish energy scenario shows actual trends and progress made by solar power. Economic concepts of levelised cost of electricity and grid parity are presented. The financial analysis shows that PV electricity achieves grid parity at a plant profitability rate up to 7.26%. (C) 2015 Elsevier Ltd. All rights reserved.
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Lobos, F., Goles, E., Ruivo, E. L. P., de Oliveira, P. P. B., & Montealegre, P. (2018). Mining a Class of Decision Problems for One-dimensional Cellular Automata. J. Cell. Autom., 13(5-6), 393–405.
Abstract: Cellular automata are locally defined, homogeneous dynamical systems, discrete in space, time and state variables. Within the context of one-dimensional, binary, cellular automata operating on cyclic configurations of odd length, we consider the general decision problem: if the initial configuration satisfies a given property, the lattice should converge to the fixed-point of all 1s ((1) over right arrow), or to (0) over right arrow, otherwise. Two problems in this category have been widely studied in the literature, the parity problem [1] and the density classification task [4]. We are interested in determining all cellular automata rules with neighborhood sizes of 2, 3, 4 and 5 cells (i.e., radius r of 0.5, 1, 1.5 and 2.5) that solve decision problems of the previous type. We have demonstrated a theorem that, for any given rule in those spaces, ensures the non existence of fixed points other than (0) over right arrow and (1) over right arrow for configurations of size larger than 2(2r), provided that the rule does not support different fixed points for any configuration with size smaller than or equal to 2(2r). In addition, we have a proposition that ensures the convergence to only (0) over right arrow or (1) over right arrow of any initial configuration, if the rule complies with given conditions. By means of theoretical and computational approaches, we determined that: for the rule spaces defined by radius 0.5 and r = 1, only 1 and 2 rules, respectively, converge to (1) over right arrow or (0) over right arrow, to any initial configuration, and both recognize the same language, and for the rule space defined by radius r = 1.5, 40 rules satisfy this condition and recognize 4 different languages. Finally, for the radius 2 space, out of the 4,294,967,296 different rules, we were able to significantly filter it out, down to 40,941 candidate rules. We hope such an extensive mining should unveil new decision problems of the type widely studied in the literature.
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Montalva-Medel, M., de Oliveira, P. P. B., & Goles, E. (2018). A portfolio of classification problems by one-dimensional cellular automata, over cyclic binary configurations and parallel update. Nat. Comput., 17(3), 663–671.
Abstract: Decision problems addressed by cellular automata have been historically expressed either as determining whether initial configurations would belong to a given language, or as classifying the initial configurations according to a property in them. Unlike traditional approaches in language recognition, classification problems have typically relied upon cyclic configurations and fully paralell (two-way) update of the cells, which render the action of the cellular automaton relatively less controllable and difficult to analyse. Although the notion of cyclic languages have been studied in the wider realm of formal languages, only recently a more systematic attempt has come into play in respect to cellular automata with fully parallel update. With the goal of contributing to this effort, we propose a unified definition of classification problem for one-dimensional, binary cellular automata, from which various known problems are couched in and novel ones are defined, and analyse the solvability of the new problems. Such a unified perspective aims at increasing existing knowledge about classification problems by cellular automata over cyclic configurations and parallel update.
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