139 research outputs found

    Mining Induced Ground Motions in a Tailings Dam

    Get PDF
    Mining induced seismicity can expose tailings dams to ground motions with potential to trigger a failure, if the structure reaches a certain level of vibrations that could exceed the seismic coefficient design criteria from pseudostatic analysis. Despite the cited risk, mainly for dams that are closer to open pits, few dams in Brazil are monitored by microseismic systems, and there are no references in the literature about continuous seismic monitoring both in open pit (source) and tailings dam, which represents the motivation of this paper. A microseismic system was commissioned in Cajati Mine, São Paulo, to record seismic events continuously in an array of 16 geophones (14 Hz and 4.5 Hz), installed in boreholes near the open pit (12 sensors) and in the dam (4 sensors), has measured values of PGA (Peak Ground Acceleration) and PGV (Peak Ground Velocity) related to 2,972 induced events from rock removal in the open pit. During the period monitored, the total of 109 events have triggered sensors in both structures, producing 920 seismograms, with the highest values of PGA and PGV of 0.0135 m/s2 (0.1358% of g) and 0.0892 mm/s. The highest PGA value is 36 times lower than the vertical coefficient of 3% of g defined by Brazilian technical standard to dam design criteria, normally used in common pseudostatic analysis from geotechnical engineers. A routine microseismic monitoring brings a new set of valuable actionable data and information to support the management of geotechnical tailings dams’ risks, under the conditions of vibrations induced by mining production

    Different Teaching Approaches and Use of Active Learning Strategies as Tools for Inter- and Transdisciplinary Education

    Get PDF
    This work reports a review on some of the ways in which education and research can be used to solve today’s complex problems by taking into account teaching and learning strategies that go beyond traditional teaching strategies. It revisits different teaching approaches and connects them directly to uni-, pluri-, multi-, inter-, and transdisciplinary attitudes, and how educational professionals think of the subject of teaching. This discussion reflects on how teachers tend to reproduce procedures they observed in their own graduation programs and why experienced teachers opt for inter- and transdisciplinary attitudes. Using a qualitative approach, this work illustrates the results from a Project-Based Learning strategy applied to a group of Major Engineering students to solve problems at the University’s Campus. Participants included 25 students engaged to Physics Engineering program supervised by different faculty members, experienced undergraduate and graduate students, and technicians, who had mentored the undergraduate students’ teams, all working in subjects closely related to the projects. The products developed by the teams show evidence that the students were motivated and engaged in the projects; this supports the premise that inter- and transdisciplinary approaches drive collaboration in the execution of projects, develop soft skills and permit knowledge development in an articulate and complex way thereby leading to a broader education of the students

    PRICE BEHAVIOR ANALYSIS OF BRAZILIAN YERBA MATE EXPORTED TO URUGUAY BETWEEN 1997 AND 2018

    Get PDF
    The objective of this study was to evaluate price seasonality of the Brazilian Yerba mate exported to the Uruguayan market, serving as a basis for decision-making to the producers. For this purpose, we collected data on Brazilian yerba mate exports to Uruguay, available in the ALICE-WEB System, which, after deflation, were used to determine the Seasonal Index for different periods between 1997 and 2018 The results showed that the market for yerba mate does not present regular historical cycles, the prices of the Brazilian product in the Uruguayan market suffer constant  falls and increases. Nevertheless, it is possible to observe a long-term trend of increasing the real price of the product at an average rate of 0.33% per month. It is possible to conclude that the price of Brazilian yerba mate in the Uruguayan market was in the ascendancy until the beginning of 2015, when the Uruguayan Justice instituted an investigation to investigate the presence of cadmium and lead at levels above the allowed ones in the Brazilian product. At the end of the study period, there was a slight tendency  to recover prices, however, only new studies will be able to verify if the price of Brazilian yerba on the Uruguayan market will reach levels similar to those registered before the judicial embargo.Keywords: international trade; seasonality; competitiveness

    Effects of repetitive transcranial magnetic stimulation on clinical, social, and cognitive performance in postpartum depression

    Get PDF
    Background: This randomized, placebo-controlled, double-blind pilot study evaluated the impact of repetitive transcranial magnetic stimulation (rTMS) on clinical, cognitive, and social performance in women suffering with postpartum depression. Methods: Fourteen patients were randomized to receive 20 sessions of sham rTMS or active 5 Hz rTMS over the left dorsolateral prefrontal cortex. Psychiatric clinical scales and a neuropsychological battery were applied at baseline (pretreatment), week 4 (end of treatment), and week 6 (follow-up, posttreatment week 2). Results: The active rTMS group showed significant improvement 2 weeks after the end of rTMS treatment (week 6) in Hamilton Depression Rating Scale (P = 0.020), Global Assessment Scale (P = 0.037), Clinical Global Impression (P = 0.047), and Social Adjustment Scale-Self Report-Work at Home (P = 0.020). Conclusion: This study suggests that rTMS has the potential to improve the clinical condition in postpartum depression, while producing marginal gains in social and cognitive function

    A relação dos fármacos agonistas de receptores GLP-1 e a proteção de doença renal para pacientes com Diabetes Mellitus

    Get PDF
    A diabetes mellitus compreende a incapacidade do organismo de desempenhar a função fisiológica da insulina, ocasionando uma grande carga de doenças, incluindo doença renal ou renal crônica e cardiovasculares. Os agonistas do receptor de GLP-1 são empregados em pacientes com diabetes tipo 2 como terapias de redução da glicose diversos à saúde destes pacientes. O objetivo deste estudo foi analisar a forma de ação dos agonistas de receptores GLP-1 como um fator de proteção à patologia renal crônica, em indivíduos portadores de diabetes mellitus do tipo 2, por meio de uma revisão bibliográfica sistemática. Os dados publicados demonstram que que agonistas do receptor GLP-1 reduzem a morte e incidência de doença renal terminal ou de insuficiência renal. Adicionalmente estes fármacos podem bloquear os mecanismos envolvidos em doenças renais, além de amenizar o estresse oxidativo e apoptose celular no rim. As terapias utilizadas com o uso de agonistas GLP-1 têm se mostrado agentes redutores da glicose e eficazes para pacientes com diabetes mellitus tipo 2, sendo recomendadas por instituições americanas e européias

    Mitochondrial physiology

    Get PDF
    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    Mitochondrial physiology

    Get PDF
    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

    Get PDF
    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Pervasive gaps in Amazonian ecological research

    Get PDF
    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

    Get PDF
    corecore