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The reproductive behaviour of the Andean catfish Astroblepus ubidiai was observed directly and with an underwater camera in a spring located next to Lago San Pablo in the province of Imbabura, Ecuador, in late 2015 and early 2016. Five mating attempts were observed, four of which were video‐taped, and two of which resulted in complete copulation. During copulation, the male grabs the female from the top of the head with its buccal disc and pelvic fins and, from this position, bends its body forming a "C" to reach the genital pore of the female and introduce its copulatory organ. Once copulation is complete, the female swims away rapidly. Details of the copulation are described here through illustrations. [ABSTRACT FROM AUTHOR]

Objective: To examine whether the effect of population aging on healthcare expenditures as a share of Gross Domestic Product (GDP) is attenuated in more educated countries. Method: The analysis is based on a dataset of 22 Latin American countries between 1995 and 2013. We estimate panel data models with country and time fixed effects, and control for potential nonlinear effects of population aging on health expenditure. Results: We find population aging increases health expenditure as a share of GDP in economies characterized by low levels of education, but this effect is mitigated in economies with higher levels of education. Results are driven by private health expenditures. Discussion: Results suggest population aging and education have a stronger influence on healthcare expenditures in less developed countries. This finding is important in a context in which the rapid growth of the aging population is likely to lead to significant costs in terms of health expenditures, but less so in more educated societies. [ABSTRACT FROM AUTHOR]

A method for the identification of single input single output linear systems is presented. The method employs a Bayesian approach to compute the posterior distribution of the model parameters given the data-set. Since this distribution is often unavailable in closed form, a Metropolis Hastings algorithm is implemented to draw samples from it. To implement the sampler, the inclusion of prior information regarding the model order of the identified system is discussed. As one of the main contributions of this work, a prior over the Hankel singular values of the model is imposed. Numerical examples illustrate the method. [ABSTRACT FROM AUTHOR]

Abstract In problems of optimal control of Markov decision processes and optimal design of experiments, the occupation measure of a Markov process is designed in order to maximize a specific reward function. When the memory of such a process is too long, or the process is non-Markovian but mixing, it makes sense to approximate it by that of a shorter memory Markov process. This note provides a specific bound for the approximation error introduced in these schemes. The derived bound is then applied to the proposed solution of a recently introduced approach to optimal input design for nonlinear systems. [ABSTRACT FROM AUTHOR]

The reproduction, feeding, parental care, growth, behavior and territoriality of Vanellus chilensis are described, based on observations of three territories around San Pablo Lake, Imbabura, Ecuador. The habitat of this species is threatened by human activities such as agriculture and livestock, which also affect other resident and migratory birds. The conservation and management of these wetlands is a priority. [ABSTRACT FROM AUTHOR]

Two types of pigmentary abnormalities in the Andean Coot Fulica ardesiaca (Rallidae) living in the San Pablo Lagoon, Imbabura-Ecuador, are presented. Several adult individuals show a variety of feather depigmentation patterns, which may be classified as partial leucism and progressive graying due to age. Whereas the first one is caused by lack of melanin and is hereditary, the second one is a progressive loss of pigment and is not necessarily hereditary. This is the first case of such pigmentary abnormalities within one meta-population in Ecuador. [ABSTRACT FROM AUTHOR]

We present a new approach to Model Predictive Control (MPC) oriented experiment design for the identification of systems operating in closed-loop. The method considers the design of an experiment by minimizing the experimental cost, subject to probabilistic bounds on the input and output signals due to physical limitations of actuators, and quality constraints on the identified model. The excitation is done by intentionally adding a disturbance to the loop. We then design the external excitation to achieve the minimum experimental effort while we are also taking care of the tracking performance of MPC. The stability of the closed-loop system is guaranteed by employing robust MPC during the experiment. The problem is then defined as an optimization problem. However, the aforementioned constraints result in a non-convex optimization which is relaxed by using results from graph theory. The proposed technique is evaluated through a numerical example showing that it is an attractive alternative for closed-loop experiment design. [ABSTRACT FROM AUTHOR]

We present a method for robust input design for nonlinear state-space models. The method optimizes a scalar cost function of the Fisher information matrix over a set of marginal distributions of stationary processes. By using elements from graph theory we characterize such a set. Since the true system is unknown, the resulting optimization problem takes the uncertainty on the true value of the parameters into account. In addition, the required estimates of the information matrix are computed using particle methods, and the resulting problem is convex in the decision variables. Numerical examples illustrate the proposed technique by identifying models using the expectation–maximization algorithm. [ABSTRACT FROM AUTHOR]

In Southern Patagonia, introduction of exotic grasses after forest fires strongly restricts restoration of Nothofagus spp forests. The use of polycarbonate shelters to shield Nothofagus seedlings has been not enough for getting restoration success. Selection of natural facilitation microsites (i.e. logs, rocks, pioneer plants) for seedling outplanting may improve early performance of Nothofagus pumilio (Poepp. et. Endl.) Krasse ( N. pumilio ), by reducing the incidence of limiting factors such as soil water and light stress. In 2012, seedlings of N. pumilio shielded with polycarnonate shelters were planted close to log piles, nurse plants of native shrubs, and open areas to evaluate the effect of natural facilitation microsites on early performance of the species. After three growing seasons, soil measurements, seedlings survival, stem diameter and height of plants, electronic transport rate, stomatal conductance, and the chlorophyll index were evaluated to explore leaf photochemistry and any possible limitation to photosynthesis associated to microsite conditions. Seedling survival was significantly lower in open sites in comparison to the other microsite conditions. Seedling height was highest both under nurse plants and log piles microsites. Stomatal conductance was higher for seedlings in nurse plant microsites despite the fact that the soil water content was similar across all conditions. Soil penetration resistance and electron transport rate were higher, but chlorophyll index was lower, in open sites when compared to the other microsites. Our results show that the use of facilitation microsites such as pioneer nurse shrubs and logs for N. pumilio reforestation or restoration plans in degraded grassland areas in Southern Patagonia should be considered even when plants are protected with polyethylene shelters. [ABSTRACT FROM AUTHOR]

The leucism is an aberration in pigmentation, resulting from a genetic abnormality and occurs in all vertebrate groups in which the fish are included. In Ecuador it has not reported such anomalies in fish. Is presented for the first time a case of partial leucism in an individual of Andean Catfish (Astroblepidae), observed in a spring located near the Lake San Pablo Canton Otavalo, Imbabura Province, Ecuador. [ABSTRACT FROM AUTHOR]

In this paper the problem of optimal input design for model identification is studied. The optimal input signal is designed by maximizing a scalar cost function of the information matrix, where the input signal is a realization of a stationary process with finite memory, with its range being a finite set of values. It is shown that the feasible set for this problem can be associated with the prime cycles in the graph of possible values and transitions for the input signal. A realization of the optimal input signal is generated by running a Markov chain associated with the feasible set, where the transition matrix is built using a novel algorithm developed for de Bruijn graphs. The proposed method can be used to design inputs for nonlinear output-error systems, which are not covered in previous results. In particular, since the input is restricted to a finite alphabet, it can naturally handle amplitude constraints. Finally, our approach relies on convex optimization even for systems having a nonlinear structure. A numerical example shows that the algorithm can be successfully used to perform input design for nonlinear output-error models. [ABSTRACT FROM AUTHOR]

Soil amendments may decrease trace element accumulation in vegetables, improving food security and allowing the recovery of contaminated farmlands. Despite some promising results in the laboratory, validation of soil amendments in field conditions are scarce, especially in aerobic soils. Here, we assessed the effect of different potential soil amendments on arsenic (As) accumulation in lettuces. Then, we compared them in terms of food security and the associated investment (efficacy and efficiency, respectively). We also hypothesized that the soil amendments do not lead to side effects, such as yield decrease, phytotoxicity of Cu, or undesired changes in soil properties. Thereby, we assessed lettuces grown on untreated contaminated soils (C+), treated contaminated soils, and untreated uncontaminated soils (C−) in two contrasting soil types (sandy and loamy soils). The treated contaminated soils consisted of multiple soil amendments. Soil amendments were: diammonium phosphate (DP), iron sulfate (IS), ferrous phosphate (FP), calcium peroxide (CP), and organic matter (OM). We found that phosphate amendments (DP and FP) reduced the As in edible tissues of lettuce in both areas, while CP only reduced As accumulation in the sandy soils area. The As intake through lettuces grown on these amended soils was about 30% lower than on the unamended ones. Cu concentrations in lettuces above 25 mg kg−1 grown in contaminated soils without reducing growth were found, a result that differed from non-field studies. [ABSTRACT FROM AUTHOR]

Abstract: Current methods to detect the colonization factor antigens (CFAs) associated with enterotoxigenic Escherichia coli (ETEC) strains are cumbersome, with some methods requiring antibodies that are not readily available. To achieve a gene-based method, we designed 2 multiplex polymerase chain reaction reactions to detect genes encoding the most common ETEC fimbrial colonization factors, including CFA/I and coli surface (CS) antigens CS1, CS2, CS3, CS4, CS5, and CS6. Analysis of 183 clinical ETEC strains shows that the most prevalent colonization factors were CFA/I only, CS1 and CS3, CS2 and CS3, and CS6 only. Interestingly, we identified 3 clinical isolates expressing CS1 only without its regulator rns. The method described here proved to be rapid and robust and correlates well with phenotypic expression of the CFAs, becoming a novel molecular diagnostic and research tool for future epidemiologic studies. [Copyright &y& Elsevier]

Chile as a major international Cu producer faces serious soil contamination issues in mining areas. Currently Chile does not have any specific law governing the maximum permissible concentrations of metals in soils to protect ecosystems and human health. Chile heavily relies on the use of environmental laws of 14 foreign countries; the choice of the country depends on the similarity of its environmental conditions with those in Chile. In this study, we used an online database to compare the similarity of Chilean rocks to those in foreign countries. Likewise, we performed soil sampling and determined the background concentrations of Cu, As, Pb, and Zn in soils of the Aconcagua basin, the largest river basin in the Valparaiso Region of central Chile. The results showed that geochemical patterns in Chile have the greatest resemblance to New Zealand, Mexico, and Italy. The background Cu concentration in the Aconcagua basin (134 mg kg−1) exceeded the legislated limits of New Zealand (100 mg kg−1) and Italy (120 mg kg−1), whereas the background Zn concentration (200 mg kg−1) exceeded the legislated limit of Italy (150 mg kg−1). Due to the elevated natural abundance of Cu and Zn in Chile, international laws should not be applied in Chile for the assessment of soil contamination. In addition, we assessed ecological risk using the results of our previous studies obtained by analyzing native field-contaminated soils of the Valparaiso region. In the Aconcagua basin, Cu posed high risk for plants in 11% of the samples, whereas As posed high risk for earthworms in 48% of the samples. We suggest that future studies are required to search for other organisms that can serve as biomarkers of metal toxicity because our previous studies were limited to plants and earthworms. Importantly, As posed high risk to human health in 25% of the samples in our study. There is a need for future studies to demonstrate empirically an association between soil As and children's blood As in order to establish the national threshold values of soil As to protect human health. We conclude that there is an urgent need in Chile to advance from the current approach of adapting foreign laws to developing Chilean sovereign environmental legislation. • Geochemically, Chile resembles New Zealand, Mexico, and Italy. • International laws are not suitable in Chile for soil contamination assessment. • Cu and Zn are naturally abundant in the soils of Chile. • Cu and As pose high ecological risk in 11% and 48% of the studied soil samples. • As poses high human health risk in 25% of the studied soil samples. [ABSTRACT FROM AUTHOR]

Using a panel data set for international corporate bonds and capital account restrictions in advanced and emerging economies, we show that restrictions on capital inflows produce a substantial and economically meaningful increase in corporate bond spreads, with a one-standard-deviation increase in our capital controls index increasing spreads by up to 35 basis points. The effect of capital controls on inflows differs across firms and across countries; the effect is particularly strong for firms that face more restricted access to alternative sources of external financing. Our findings establish a novel channel through which capital controls affect economic outcomes. [ABSTRACT FROM AUTHOR]

This paper introduces a model in which greater inequality reduces growth in economies with low levels of financial development but that this effect is attenuated in economies with more developed systems. The model also predicts that individuals in economies with developed financial markets have a higher tolerance to inequality. Using a panel dataset that covers a large number of countries, this paper shows empirical evidence that is consistent with the main predictions of the model. Overall, this paper's major findings highlight that some of the pernicious effects of inequality can be attenuated by improving access to credit. [ABSTRACT FROM AUTHOR]

Abstract: Glu-tRNA is either bound to elongation factor Tu to enter protein synthesis or is reduced by glutamyl-tRNA reductase (GluTR) in the first step of tetrapyrrole biosynthesis in most bacteria, archaea and in chloroplasts. Acidithiobacillus ferrooxidans, a bacterium that synthesizes a vast amount of heme, contains three genes encoding tRNAGlu. All tRNAGlu species are substrates in vitro of GluRS1 from A. ferrooxidans. , that fulfills the requirements for protein synthesis, is not substrate of GluTR. Therefore, aminoacylation of might contribute to ensure protein synthesis upon high heme demand by an uncoupling of protein and heme biosynthesis. [Copyright &y& Elsevier]