909 research outputs found

    The influence of human activities on streamflow reductions during the megadrought in central Chile

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    Since 2010, central Chile has experienced a protracted megadrought with annual precipitation deficits ranging from 25 % to 70 %. An intensification of drought propagation has been attributed to the effect of cumulative precipitation deficits linked to catchment memory. Yet, the influence of water extractions on drought intensification is still unclear. Our study assesses climate and water use effects on streamflow reductions during a high-human-influence period (1988–2020) in four major agricultural basins. We performed this attribution by contrasting observed streamflow (driven by climate and water use) with near-natural streamflow simulations (driven mainly by climate) representing what would have occurred without water extractions. Near-natural streamflow estimations were obtained from rainfall–runoff models trained over a reference period with low human intervention (1960–1988). Annual and seasonal streamflow reductions were examined before and after the megadrought onset, and hydrological drought events were characterized for the complete evaluation period in terms of their frequency, duration, and intensity. Our results show that before the megadrought onset (1988–2009) the mean annual deficits in observed streamflow ranged between 2 % and 20 % across the study basins and that 81 % to 100 % of those deficits were explained by water extractions. During the megadrought (2010–2020), the mean annual deficits in observed streamflow were 47 % to 76 % among the basins. During this time, the relative contribution of precipitation deficits on streamflow reduction increased while the contribution of water extractions decreased, accounting for 27 % to 51 % of the streamflow reduction. Regarding drought events during the complete evaluation period, we show that human activities have amplified drought propagation, with almost double the intensity of hydrological droughts in some basins compared to those expected by precipitation deficits only. We conclude that while the primary cause of streamflow reductions during the megadrought has been the lack of precipitation, water uses have not diminished during this time, causing an exacerbation of the hydrological drought conditions and aggravating their impacts on water accessibility in rural communities and natural ecosystems.</p

    Diferencias nas decisões utilitárias e morais entre homens e mulheres

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    Objective. Moral judgments are based on decisions that take into account the representation of norms and law, values, functionality and situations themselves. Morality has been studied with “hypothetic moral dilemmas”, in order to identify the type of outcome and the process behind moral reasoning. But judgments by themselves are not enough to establish differences in the type of resolution or the relationship with other cognitive processes. The present paper aimed to compare performance in tasks of utility maximization, cognitive control, and moral judgments, taking into account sex and other sociodemographic variables. Method. Seventy-three university students participated (50 women, 20 men and 3 with unreported gender, the average age was 19.53 years (SD = 1.68 years). The Iowa Gambling Task (IGT) was used to identify behaviors of utility maximization. In addition, we used the switch costs and the web application of moral machine tasks. Results. A difference between variables of the IGT, but no differences in the switch costs task were found. Conclusion. Regarding moral judgment, males gave more value to respect norms than females. Some variables of the IGT task support outcomes related to differences between sexes. Results are congruent with differences shown in existing literature.Objetivo. Los juicios morales se basan en decisiones que toman en cuenta la representación de las normas y la ley, los valores, la funcionalidad y la situación en sí. La moral se ha estudiado con "dilemas morales hipotéticos" para identificar el tipo de resultado y el proceso detrás del razonamiento moral. No obstante, los juicios en sí mismos no son suficientes para establecer diferencias en el tipo de resolución o la relación con otros procesos cognitivos. Por lo anterior, el presente estudio buscó comparar el desempeño en tareas de maximización de la utilidad, control cognitivo y juicios morales, teniendo en cuenta el sexo y otras variables sociodemográficas. Método. Participaron 73 estudiantes universitarios (50 mujeres, 20 hombres y 3 con sexo no reportado, la edad promedio fue 19.53 años (DE = 1.68 años). El Iowa Gambling Task (IGT) se utilizó para identificar comportamientos de maximización de la utilidad. Además, el estudio empleó la prueba de cambios de tarea y la aplicación web Máquina Moral. Resultados. Se encontró una diferencia entre las variables de IGT, sin observar diferencias en la prueba de cambios de tarea. Conclusión. En cuanto al juicio moral, los hombres dieron más valor al cumplimiento de normas que las mujeres. Algunas variables de la tarea IGT apoyan las diferencias entre los sexos. Los resultados son congruentes con las diferencias mostradas por la literatura.Escopo. Os juízos morais estão baseados em decisões que levam em conta a representação das normas e a lei, os valores, a funcionalidade e a situação concreta. A moral tem se estudado com “dilemas morais hipotéticos” para identificar o tipo de resultado e o processo detrás do razoamento moral. Mas os juízos em si não são suficientes para estabelecer diferencias no tipo de resolução ou a relação com outros processos cognitivos. Por tanto, o escopo de este estudo foi comparar o desempenho em tarefas de maximização da utilidade, controle cognitivo e juízos morais, levando em conta o sexo e outras variáveis sócio demográficas. Metodologia. Participaram 73 estudantes universitários (50 mulheres, 20 homens e 3 com sexo não reportado, a idade de média foi de19.3 anos, (DE = 1.68 anos). O Iowa Gambling Task (IGT) foi utilizado para identificar comportamentos de maximização da utilidade. Além, o estudo empregou a prova de mudança de tarefa e a aplicação web Máquina Moral. Resultados. Foi achada uma diferencia entre as variáveis de IGT, mas não há diferencias na prova de mudança de tarefa. Em quanto ao juízo moral, os homens deram mais valor ao cumprimento de normas que as mulheres. Algumas variáveis da tarefa IGT apoiam as diferencias entre os sexos. Conclusão. Os resultados são congruentes com as diferencias mostradas na literatura

    Remotely Piloted Aircraft Systems and a Wireless Sensors Network for Radiological Accidents

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    In critical radiological situations, the real time information that we could get from the disaster area becomes of great importance. However, communication systems could be affected after a radiological accident. The proposed network in this research consists of distributed sensors in charge of collecting radiological data and ground vehicles that are sent to the nuclear plant at the moment of the accident to sense environmental and radiological information. Afterwards, data would be analyzed in the control center. Collected data by sensors and ground vehicles would be delivered to a control center using Remotely Piloted Aircraft Systems (RPAS) as a message carrier. We analyze the pairwise contacts, as well as visiting times, data collection, capacity of the links, size of the transmission window of the sensors, and so forth. All this calculus was made analytically and compared via network simulations

    Burning in the management of heathlands of Erica ciliaris and Erica tetralix: effects on structure and diversity

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    Can controlled burning be used as a management tool of Erica ciliaris and Erica tetralix wet heathlands? Two E. ciliaris and E. tetralix communities were selected and two 5 x 5 m plots were established in each. These were then characterised on the basis of frequency and cover values and plant species composition. They were subjected to experimental burning, after which the plots were sampled twice a year during the following four and a half years. The results show that the cover of woody species very quickly attained the values of the Control Plots. Diversity and species composition did not suffer notable changes during this period, however, temporal heterogeneity indicates that the main changes occur in the first 18 months of secondary succession. The multivariate analysis showed that the samples registered during this time were grouped as a function of the cover values of the species, which shows that stages exist in the vegetation recovery of these communities. The damage produced by fire in the community is minor, as a rapid recovery of the vegetation was observed, so controlled burning is a useful tool in the management of these heathlands

    WMR Kinematic Control Using Underactuated Mechanisms for Goal Direction and Evasion

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    This work presents the mechanical design and the kinematic navigation control system for a tricycle-wheeled robot (one drive-steer and two lateral fixed passive) with two underactuated mechanisms: a global compass and local evasive compass. The proposed goal-reference mechanism is inspired by the ancient Chinese south-seeking chariot (c. 200–265 CE) used as a navigation compass. The passive lateral wheels transmit an absolute angle from its differential speeds to automatically steer the front wheel. An obstacle-evasive compass mechanism is commutated for steering control when detecting nearby obstacles. The absolute and local compass mechanisms commutate each other to control to the robot’s steering wheel to reach a goal while avoiding collisions. A kinematic control law is described in terms of the robot’s geometric constraints and is combined with a set of first-order partial derivatives that allows interaction between the global and local steering mechanisms. Animated simulations and numerical computations about the robot’s mechanisms and trajectories in multi-obstacle scenarios validate the proposed kinematic control system and its feasibility

    Evaluating the capacity of human gut microorganisms to colonize the zebrafish larvae (Danio rerio)

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    Indexación: Scopus.In this study we evaluated if zebrafish larvae can be colonized by human gut microorganisms. We tested two strategies: (1) through transplantation of a human fecal microbiota and (2) by successively transplanting aerotolerant anaerobic microorganisms, similar to the colonization in the human intestine during early life. We used conventionally raised zebrafish larvae harboring their own aerobic microbiota to improve the colonization of anaerobic microorganisms. The results showed with the fecal transplant, that some members of the human gut microbiota were transferred to larvae. Bacillus, Roseburia, Prevotella, Oscillospira, one unclassified genus of the family Ruminococcaceae and Enterobacteriaceae were detected in 3 days post fertilization (dpf) larvae; however only Bacillus persisted to 7 dpf. Successive inoculation of Lactobacillus, Bifidobacterium and Clostridioides did not improve their colonization, compared to individual inoculation of each bacterial species. Interestingly, the sporulating bacteria Bacillus clausii and Clostridioides difficile were the most persistent microorganisms. Their endospores persisted at least 5 days after inoculating 3 dpf larvae. However, when 5 dpf larvae were inoculated, the proportion of vegetative cells in larvae increased, revealing proliferation of the inoculated bacteria and better colonization of the host. In conclusion, these results suggest that it is feasible to colonize zebrafish larvae with some human bacteria, such as C. difficile and Bacillus and open an interesting area to study interactions between these microorganisms and the host. © 2018 Valenzuela, Caruffo, Herrera, Medina, Coronado, Feijóo, Muñoz, Garrido, Troncoso, Figueroa, Toro, Reyes-Jara, Magne and Navarrete.https://www.frontiersin.org/articles/10.3389/fmicb.2018.01032/ful

    1358-P: Point of Care OGTT for the Screening of Gestational Diabetes: A Feasible Proposal for Low-Resource Settings

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    Due to the ubiquity of risk factors associated with gestational diabetes (GDM) in Mexican women and the low availability of the Oral Glucose Tolerance Test (OGTT), we compared the efficacy of two point of care (POC) models for GDM detection against the plasmatic 2hr OGTT-75gr in primary health care clinics in Mexico. We evaluated 328 pregnant women without previous diabetes diagnosis from a prospective cohort study “Cuido mi embarazo”; all of them were tested with the gold standard plasmatic 2hr OGTT-75gr for the diagnosis of GDM based on the ADA 2019 criteria. Simultaneously, we measured with a glucometer (ACCU-CHEK instant®) the glucose concentration either by capillary whole blood (172 measures) or from venous whole blood (156 measures). We evaluated the diagnostic accuracy by calculating the sensitivity, specificity, and ROC curve of each of the glucometer test results compared to the plasmatic test. For the first model, POC venous OGTT, the incidence of GDM was 41.66% compared to 7.05% of the plasmatic test. The ROC area under the curve for GDM prediction was 0.81 (95% CI 0.77-0.85), with a sensitivity of 100% and specificity of 62.8%. The low specificity is dependent on the fasting venous value of 64% since it was compared to 95% and 97% specificity of the 1hr and 2hr values, respectively. The second model, POC capillary OGTT, had an incidence of GDM of 30.23% compared to 8.13% of the plasmatic test. It had lower sensitivity (78.57%) and higher specificity (74.1%) compared to the first model, having an overall 0.76 (95% CI 0.65-0.88) ROC area under the curve for GDM prediction. We propose POC venous OGTT as a feasible diagnostic alternative for low resource settings where laboratory infrastructure is not available. Its positive bias could be beneficial since the treatment and control of early cases is related to better health outcomes for the moms and their babies. Further analysis is needed to improve GDM, POC screening interventions. Disclosure H. Gallardo: None. J. Lomelin-Gascon: Other Relationship; Self; Lilly Global Health Partnership. L.A. Martinez: Other Relationship; Self; Lilly Global Health Partnership. A. Montoya: None. E. Reyes-Muñoz: None. R.C. Tapia-Conyer: None. Funding Eli Lilly and Company </jats:sec
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