2,679 research outputs found
Considerations on the Lift Force
Many authors at criticizing the conventional explanation of aerodynamic lift based on Bernoulli\u27s law commit the same mistake laying within the scope of mechanics and ignoring the effects of viscosity in the generation of forces. Because it is an irreversible process, we affirm that it is not possible to generate lift without increasing entropy. And for an increase of entropy it must be considered the viscosity and vorticity
Toxicological Study Employing Repeated Doses of Garcinielliptone FC, a Polyisoprenylated-Benzophenone Isolated from Seed of Platonia Insignis Mart
The major constituent from the hexane extract of the seeds of P. insignis is GFC (garcinielliptone FC). Doses of 25, 50and 75 mg/kg of GFC were aseptically suspended in 0.05% Tween 80 dissolved in 0.9% saline (vehicle) and orally administered for30, 90 and 120 consecutive days to adult Swiss mice. In this work, the repeated oral administration, in animals of both sexes,demonstrates that this compound is not able to induce mortality and/or behavioral changes in adult mice. In addition, body weightgain, feed intake and disposal of excreta were not altered by the administration of this compound with repeated doses. Furthermore,no differences in weight and macroscopic structure of the brain, liver, kidney, lung, heart and spleen between groups of male andfemale adult mice were observed after treatment. During the periods of treatment, GFC produced no significant changes onhaematological and biochemical parameters in male and female mice treated with all doses used. The aim of this study was toinvestigate the toxicological potential of GFC through behavioral, hematological, biochemical and morphological parameters inanimals in order to ensure the safe use of Platonia insignis in folk medicine.Fil: Silva, Ana P.. Federal University of Piauí; BrasilFil: Filho, José Carlos C. L. S.. North Union of Parana; BrasilFil: da Costa Júnior, Joaquim S.. Federal Institute of Piauí; BrasilFil: Peláez, Walter José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Faillace, Martín Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Falcão Ferraz, Alexandre de B.. Lutheran University of Brazil; BrasilFil: David, Jorge M.. Institute Of Chemistry, Federal University Of Bahia; Brasil. Universidade Federal da Bahia; BrasilFil: Freitas, Rivelilson M.. Federal University of Bahia; Brasi
Directives for Sustainability Management in the Amazon Forest Economy
This paper presents drivers to promote sustainable management in the forest economy in Rondocirc;nia, as an alternative to the traditional economic approach to forest resources. Therefore, the study questions how the forest management in the State of Rondocirc;nia can contribute as an alternative to the predatory use of the forest, mitigating the impact on the Amazonian socio-biodiversity. The general objective is to generate knowledge about the exploitation of timber and non-timber resources in Rondocirc;nia, and has as specific goals to promote the survey of the theme, as indicated in theory and according to practices carried out in the State of Rondocirc;nia / Brazil (1); to discuss the main characteristics of forest management with sustainability, promoting its multifaceted characterization in the face of commercial and intercropping (2); and finally, to address the alternative uses of Forest Management, indicating drivers and adaptive the spatial conditions of the Amazon region, specifically Rondocirc;nia (3). This research is characterized as qualitative with the method of content analysis; involved the raising of theoretical bases that describe the scenario of study and consultation of specialists, to promote the proficient contextualization, analysis, and inference of the results. It was verified that the drivers for sustainable forest management are alternatives to the predatory use of natural resources, providing the use of multiple conservative mechanisms, interrelating profitability and sustainable development, in favor of the emergence and consolidation of an integrated forest production chain with diversified industrial systems. This work is of interest to the scientific community and rural managers and producers since it offers a contribution to the management of forest resources with sustainability
Are there any risks of the disposal of pesticide effluents in soils? Biobed system meets ecotoxicology ensuring safety to soil fauna.
The biobed is a purification system, which reduces soil pollution for receiving pesticide residues from handling and washing machinery in agricultural areas. The aims of this study were (1) to assess ecotoxicity effects over time to soil fauna, posed by Lorsban® 480 BR (Chlorpyrifos) and Dithane® NT (Mancozeb) residues when disposed of in a biobed system compared with two subtropical soils, and (2) to assess ecotoxicity effects over time to soil fauna simulating an accidental spillage with Lorsban® 480 BR at the biobed. A semi-field experiment was conducted for 420 days in southern Brazil, testing continuous disposal of washing pulverization tanks in biobeds, Typic Haploperox or Typic Hapludults. In addition, different biobeds received a single dose (1 L) of Lorsban® 480 BR to simulate an accidental spillage. Chronic ecotoxicity tests were performed using Folsomia candida, Eisenia andrei, and Enchytraeus crypticus in different sampling times for both experiments.F. candida was the most sensitive species. The biobed system was able to eliminate effects from residues of both pesticides over time in all species, which did not happen in both natural soils. In accidental spillage simulation, even 420 days after contamination, F. candida did not show reproduction. The biobeds can be a feasible alternative for the disposal and treatment residues of pesticides, also for handling and washing pesticides activities. The system was efficient in promoting degradation and reducing ecotoxicity effects posed by Lorsban® 480 BR and Dithane® NT for soil fauna. It is a safe alternative to avoid soil contamination
Use of the Hospital Anxiety and Depression Scale (HADS) in a Cardiac Emergency Room – Chest Pain Unit
OBJECTIVE: To determine the prevalence of anxiety and depression in patients complaining of chest pain who seek a chest pain unit attendance. INTRODUCTION: Patients arriving at a Chest Pain Unit may present psychiatric disorders not identified, isolated or co-morbid to the main illness, which may interfere in the patient prognosis. METHODOLOGY: Patients were assessed by the "Hospital Anxiety and Depression Scale" as a screening instrument wile following a systematized protocol to rule out the diagnosis of acute coronary syndrome and other potentially fatal diseases. Patients with 8 or more points in the scale were considered "probable case" of anxiety or depression. RESULTS: According to the protocol, 59 (45.4%) of 130 patients studied presented Chest Pain of Determined Cause, and 71 (54.6%) presented Chest Pain of Indefinite Cause. In the former group, in which 43 (33.1%) had acute coronary syndrome, 33.9% were probable anxiety cases and 30.5% depression cases. In the second group, formed by patients without acute coronary syndrome or any clinical conditions involving greater morbidity and mortality risk, 53.5% were probable anxiety cases and 25.4% depression. CONCLUSION: The high anxiety and depression prevalence observed may indicate the need for early and specialized approach to these disorders. When coronary arterial disease is present, this may decrease complications and shorten hospital stay. When psychiatric disorder appears isolated, is possible to reduce unnecessary repeated visits to emergency room and increase patient's quality of life
Associação entre características de desempenho de tilápia-do-nilo ao longo do período de cultivo.
O objetivo deste trabalho foi estimar as herdabilidades e a estrutura de correlações genéticas entre as características de desempenho de tilápia-do-nilo (Oreochromis niloticus) da linhagem GIFT, em diferentes estágios do ciclo de produção. As tilápias foram cultivadas em tanques - rede. Mediu-se ganho em peso diário total, peso vivo e ganho em peso diário, em quatro períodos, com intervalos de aproximadamente 30 dias. Foram realizadas análises unicaracter para as medidas, em todas as biometrias e, nas análises bicaracter, as medidas de mesma característica foram combinadas duas a duas e com o ganho em peso diário total. As estimações de herdabilidade variaram de 0,15 a 0,11 para peso vivo, 0,16 a 0,09 para ganho em peso diário e 0,17 a 0,12 para ganho em peso diário total, nas análises unicaracter. Os valores estimados de correlação genética para peso vivo e ganho em peso diário, associados ao ganho em peso diário total, variaram entre 0,37 a 0,98 e 0,74 a 0,8 respectivamente. A forte associação genética estimada entre peso vivo em biometrias intermediárias e ganho em peso diário total sugere que a seleção para velocidade de crescimento pode ser realizada de forma precoce
Equine poisoning by coffee husk (Coffea arabica L.)
<p>Abstract</p> <p>Background</p> <p>In Brazil, coffee (<it>Coffea arabica</it>) husks are reused in several ways due to their abundance, including as stall bedding. However, field veterinarians have reported that horses become intoxicated after ingesting the coffee husks that are used as bedding. The objective of this study was to evaluate whether coffee husk consumption causes intoxication in horses.</p> <p>Results</p> <p>Six horses fed coast cross hay <it>ad libitum </it>were given access to coffee husks and excitability, restlessness, involuntary muscle tremors, chewing movements and constant tremors of the lips and tongue, excessive sweating and increased respiration and heart rates were the most evident clinical signs. Caffeine levels were measured in the plasma and urine of these horses on two occasions: immediately before the coffee husks were made available to the animals (T0) and at the time of the clinical presentation of intoxication, 56 h after the animals started to consume the husks (T56). The concentrations of caffeine in the plasma (p < 0.001) and urine (p < 0.001) of these animals were significantly greater at T56 than at T0.</p> <p>Conclusions</p> <p>It was concluded that consumption of coffee husks was toxic to horses due to the high levels of caffeine present in their composition. Therefore, coffee husks pose a risk when used as bedding or as feed for horses.</p
Digital simulators in the epistemological context of Gagné and Vygotsky : a didactic intervention proposal on electricity and electrical circuits
Este artigo apresenta uma proposta de intervenção didática, usando como referenciais teóricos Robert Gagné e Lev Vygotsky, envolvendo a utilização de simuladores experimentais como recurso didático. Tais referenciais são harmonizados entre si e, dessa harmonização, emergem importantes elementos ao processo de ensino e aprendizagem em física. A utilização de simuladores leva
em consideração o crescente uso das Tecnologias Digitais da Informação e Comunicação pelos estudantes na cultura digital, bem como sua relevância ao desenvolvimento de habilidades sociointeracionistas, que formam eixo central da perspectiva de Vygotsky. A intervenção didática sugerida trata do tema eletricidade e construção de circuitos elétricos, como exemplo prático de aplicação de simuladores no processo pedagógico. Além disso, condizente com o referencial teórico adotado, é utilizado o conceito de Zona de Desenvolvimento Proximal, para avaliação tantos dos estudantes, quanto da didática do professor.This article provides a didactic intervention proposal, using Robert Gagné and Lev Vygotsky as theoretical references, involving experimental simulators as a didactic resource. Such references are harmonized with each other, and, as a result of this merge, important elements for to the teaching and learning process in Physics emerge. The use of simulators considers the increasing
usage of Digital Information and Communication Technologies by students immersed in a digital culture and their relevance for the development of social-interactionist skills, which form the basis of Vygotsky’s perspective. The suggested didactic intervention deals with the theme of electricity and the construction of electrical circuits as a practical example of the application of simulators
in the pedagogical process. In addition, aligned with this theoretical framework, the concept of Zone of Proximal Development is used to assess both students and the teacher’s didactics
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