Vertical segregation among pathways mediating nitrogen loss (N2 and N2O production) across the oxygen gradient in a coastal upwelling ecosystem

Indexación: ScopusThe upwelling system off central Chile (36.5 S) is seasonally subjected to oxygen (O2)-deficient waters, with a strong vertical gradient in O2 (from oxic to anoxic conditions) that spans a few metres (30-50€m interval) over the shelf. This condition inhibits and/or stimulates processes involved in nitrogen (N) removal (e.g. anammox, denitrification, and nitrification). During austral spring (September 2013) and summer (January 2014), the main pathways involved in N loss and its speciation, in the form of N2 and/or N2O, were studied using 15N-tracer incubations, inhibitor assays, and the natural abundance of nitrate isotopes along with hydrographic information. Incubations were developed using water retrieved from the oxycline (25€m depth) and bottom waters (85€m depth) over the continental shelf off Concepción, Chile. Results of 15N-labelled incubations revealed higher N removal activity during the austral summer, with denitrification as the dominant N2-producing pathway, which occurred together with anammox at all times. Interestingly, in both spring and summer maximum potential N removal rates were observed in the oxycline, where a greater availability of oxygen was observed (maximum O2 fluctuation between 270 and 40€μmol€L'1) relative to the hypoxic bottom waters ( < €20€μmol€O2€L'1). Different pathways were responsible for N2O produced in the oxycline and bottom waters, with ammonium oxidation and dissimilatory nitrite reduction, respectively, as the main source processes. Ammonium produced by dissimilatory nitrite reduction to ammonium (DNiRA) could sustain both anammox and nitrification rates, including the ammonium utilized for N2O production. The temporal and vertical variability of /15N-NO3' confirms that multiple N-cycling processes are modulating the isotopic nitrate composition over the shelf off central Chile during spring and summer. N removal processes in this coastal system appear to be related to the availability and distribution of oxygen and particles, which are a source of organic matter and the fuel for the production of other electron donors (i.e. ammonium) and acceptors (i.e. nitrate and nitrite) after its remineralization. These results highlight the links between several pathways involved in N loss. They also establish that different mechanisms supported by alternative N substrates are responsible for substantial accumulation of N2O, which are frequently observed as hotspots in the oxycline and bottom waters. Considering the extreme variation in oxygen observed in several coastal upwelling systems, these findings could help to understand the ecological and biogeochemical implications due to global warming where intensification and/or expansion of the oceanic OMZs is projected.https://www.biogeosciences.net/14/4795/2017

Two Fundamental Concepts in Skeletal Parallel Programming

We define the concepts of nesting mode and interaction mode as they arise in the description of skeletal parallel programming systems. We sugegs

Patterns of Social Activity Engagement Among Older Hispanics and Their Relationship to Sociodemographic and Health Variables

The purpose of this study was to examine patterns of social activity engagement in a sample of older Hispanics (Puerto Rican, Dominican, and other Hispanic) and determine whether these patterns differed significantly from the comparison non-Hispanic White group. This article also analyzes how ethnicity, sociodemographic, and health variables (health problems and depression) relate to each of the activity engagement patterns. The factor analysis of social activities from the Norbeck Social Support Questionnaire yielded three factors, which describe engagement in social activities as: children and relatives active, friends and activities active, and senior services active. The results from the regression analyses show that Hispanic ethnicity and education are positively associated with being more engaged in activities with children and relatives, whereas being male and especially a male living alone is inversely associated with this pattern. In addition, being friends and activities active shows positive association with education, the participant living alone, and experiencing more language inclusion; however, it is inversely associated with depression, age, being male, and number of health problems. Finally, engaging in activities offered by senior services is only significantly associated with increased age and the number of health problems. The interpretations of these findings, directions for future research, and implications for activity professionals/recreation therapists are also discussed

An analysis of the dynamics of efficiency of mutual funds

This paper studies the efficiency of a sample of mutual funds that invest in the United States. Estimating a production function using Bayesian stochastic frontier analysis, we find evidence that the underlying technology presents economies of scale both at the fund and firm level. We also find evidence that informational asymmetries affect efficiency. Funds that invest domestically are likely to be more efficient than foreign funds investing in the US. Moreover, an inspection at the distribution process shows that funds sold directly to investors rather than by financial intermediaries are more efficient. The level of inefficiency persistence is overall high.Persistency of inefficiency is particularly higher for ethical funds, funds oriented to large firm sand lower in funds oriented to growth firms. The analysis done in two separate periods also shows that the efficiency of the funds changes. In particular, funds oriented to non-ethical, small and growth firms become more efficient over the period. Finally, funds' efficiency decreases during global financial crisis, but at the end of the sample period some funds recover and their efficiency levels are higher than those registered before the financial crisis. Our results have implications for investors' decisions in mutual funds.The authors acknowledge financial support from Fundação para a Ciência e Tecnologia PEst-OE/EGE/UI0315/2011 and from the Spanish Ministry of Education and Science, research project ECO2012-3240

Deep Spiking Neural Network model for time-variant signals classification: a real-time speech recognition approach

Speech recognition has become an important task to improve the human-machine interface. Taking into account the limitations of current automatic speech recognition systems, like non-real time cloud-based solutions or power demand, recent interest for neural networks and bio-inspired systems has motivated the implementation of new techniques. Among them, a combination of spiking neural networks and neuromorphic auditory sensors offer an alternative to carry out the human-like speech processing task. In this approach, a spiking convolutional neural network model was implemented, in which the weights of connections were calculated by training a convolutional neural network with specific activation functions, using firing rate-based static images with the spiking information obtained from a neuromorphic cochlea. The system was trained and tested with a large dataset that contains ”left” and ”right” speech commands, achieving 89.90% accuracy. A novel spiking neural network model has been proposed to adapt the network that has been trained with static images to a non-static processing approach, making it possible to classify audio signals and time series in real time.Ministerio de Economía y Competitividad TEC2016-77785-

The impact of body image on the WTP values for reduced-fat and low-salt content potato chips among obese and non-obese consumers

The aim of this study is to assess the influence of body image on consumers’ willingness to pay (WTP) for potato chips carrying nutritional claims among obese and non-obese people. About 309 and grouped in: (i) non-obese with good body image; (ii) non-obese with body image dissatisfaction; and grouped in: (i) non-obese with good body image; (ii) non-obese with body image dissatisfaction; (iii) obese with good body image; (iv) obese with body image dissatisfaction. Results indicate differences in consumers’ willingness to pay among consumer groups. Body image dissatisfaction of normal people did not influence the WTP for healthier chips. Obese people with body image dissatisfaction were willing to pay more for healthier chips (i.e., low-salt content potato chips) than normal ones with body image dissatisfaction. Examining the role of knowledge in the light of how this could impact on body image is relevant to improve the health status of individuals and their diet. Knowledge about nutrition could improve the body image of obese people

Hegemonic Masculinity and Counter-hegemonic Feminist Discourses for Peace

Utilizing a pacifist feminist position, this paper looks at the relationship between ideas of masculinity and war, militarism and peacekeeping intervention. I argue that it is necessary to revise and redefine a pacifist feminist position, especially because, from this viewpoint, the current masculinist war-prone world order may best be combated by attacking its gender biases. In this context, pacifist feminists have often been challenged by non-feminists, but also by non-pacifist feminists who accuse them of drawing on essentialist notions of women as peace –makers. A non-violent attack on oppressive masculinity would need to be successful in disseminating a counter-hegemonic and non-essentialist, non-violent feminist education not just in academia, but also through increased access of pacifist feminist perspectives in the media

Efficient multi-task progressive learning for semantic segmentation and disparity estimation

Scene understanding is an important area in robotics and autonomous driving. To accomplish these tasks, the 3D structures in the scene have to be inferred to know what the objects and their locations are. To this end, semantic segmentation and disparity estimation networks are typically used, but running them individually is inefficient since they require high-performance resources. A possible solution is to learn both tasks together using a multi-task approach. Some current methods address this problem by learning semantic segmentation and monocular depth together. However, monocular depth estimation from single images is an ill-posed problem. A better solution is to estimate the disparity between two stereo images and take advantage of this additional information to improve the segmentation. This work proposes an efficient multi-task method that jointly learns disparity and semantic segmentation. Employing a Siamese backbone architecture for multi-scale feature extraction, the method integrates specialized branches for disparity estimation and coarse and refined segmentations, leveraging progressive task-specific feature sharing and attention mechanisms to enhance accuracy for solving both tasks concurrently. The proposal achieves state-of-the-art results for joint segmentation and disparity estimation on three distinct datasets: Cityscapes, TrimBot2020 Garden, and S-ROSeS, using only of the parameters of previous approaches.This work was supported by the I+D+i project TED2021-132103A-I00 (DOREMI), funded by MCIN/AEI /10.13039/501100011033