1000 resultados para Millora ambiental
Resumo:
L’objectiu del present estudi es realitzar una proposta i una aplicació pràctica per comprovar els efectes d’entrenament que genera sobre la velocitat amb el canvi de direcció. Per poder dur a terme la investigació, es van reunir a 11 jugadores (11.25 ± 0.79 d’edat) d’un mateix equip que competeixen a la categoria aleví. Es va crear un grup experimental (GEX) format per sis jugadores, el qual va ser sotmès al programa d’entrenament juntament al realitzat habitualment amb el seu equip. Els exercicis realitzats en el programa eren de pliometria amb salts a tanques petites i a bancs, circuits de carreres amb canvis de direcció i exercicis pliomètrics de baix impacte mitjançant un treball de peus coordinatius a l’escala de coordinació, tot això, alternat amb els jocs tradicionals de persecució i oposició. Es va crear un segon grup, anomenat grup control (GC) format per cinc jugadores, les quals només van realitzar el seu treball de futbol habitual amb el seu equip. Els protocols d’avaluació van ser el Test Illinois i el T-Test abans de l’inici del programa i després de l’aplicació pràctica amb el grup experimental. Es va establir un nivell de significació de p<0.05. Els resultats al final de l’estudi van mostrar que el grup GEX va millorar de manera estadísticament significativa en els dos tests, tot i això, el grup GC va obtenir una millora encara més significativa que el GEX en el Test Illinois. Això ens demostra que el programa d’entrenament realitzat es més efectiu en T-Test que no pas en el Test Ilinois.
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In this work, analytical strategies are evaluated in order to measure accurately the ambient levels of atmospheric organic acids. Environmental considerations about the determination of low molecular weight mono- and di-carboxylic acids from urban areas of São Paulo are described.
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Mercury kept in a garage of a residencial building in Rio de Janeiro was accidentally released and caused local (environmental and human) contamination. The concentration of mercury in indoor air of the most critical site reached 15.5 mg/m³. Outdoor air samples showed concentrations ranging from 0.37 to 6.6 mg/m³ . Seventy five per cent of the urine samples collected from 22 residents in the contaminated building showed levels of mercury higher than those observed in non exposed individuals (>6.9 mg/L); in 30% of these samples, the concentration was higher than 20 mg/L. These values show a high level of human contamination and the final consequences were not so serious owing to the quick action taken by one of the residents.
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This article gives some basic principles of heterogeneous photocatalysis using titanium dioxide as photocatalyst and the state of art of its applications to the abatement of aqueous and atmospheric pollutants.
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This work considers mainly the problem of environmental pollution due to the production of energy by burning fossil fuels, particularly in urban vehicles. Electrochemical energy conversion is proposed as a partial solution to this problem, through the use of hydrogen in fuel cells. In both the production of hydrogen by electrolysis and in the electrochemical processes in fuel cells, the key factor is electrocatalysis. The concept of electrocatalysis, the production of catalysts and supported catalysts and their use in practical systems for the conversion of energy is discussed.
Resumo:
Phenols are widely used in many areas and commonly found as industrial by-products. A great number of agricultural and industrial activities realise phenolic compounds in the environmental. Waste phenols are produced mainly by the wood-pulp industry and during production of synthetic polymers, drugs, plastics, dyes, pesticides and others. Phenols are also released into the environmental by the degradation of pesticides with phenolic skeleton. The phenols level control is very important for the environmental protection. Amperometric biosensor has shown the feasibility to complement laboratory-based analytical methods for the determination of phenolic compounds, providing alternatives to conventional methods which have many disadvantages. This brief review considers the evolution of an approach to amperometric measurement using the catalytic properties of some enzymes for phenolic compounds monitoring.
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Pollen allergy has a remarkable clinical impact all over Europe, and there are evidences that the prevalence of allergic respiratory induced reactions by pollen in Europe has been increasing in recent decades. The presence of potentially allergenic ornamental species in the town of Tiana, representing 41% of total species recorded. Approximately 28% of these species are Platanus acerifolia. This study attempts to relate the effect it has on the people’s health, the presence of certain urban ornamental plants by identifying and locating the ornamental trees in the town.
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The oxidation process of sulfur(IV) species by oxygen, ozone and nitrogen oxides, catalysed by trace metal ions, can play an important role in atmospheric chemistry processes like acid rain, visibility degradation and health hazard. An overview of the more relevant investigations on emissions sources, aqueous phase conversion process and environmental impact is presented.
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El actual incremento de medusas en las costas mediterráneas, percibido como un factor negativo en la calidad de las playas, supone un factor reductor de la demanda turística en las ubicaciones costeras, sobre todo en aquellas más afectadas por éstas proliferaciones. Debido a que la época de mayor presencia de fitoplacton disponible (principal fuente de alimento de las medusas), relacionada a la alta incidencia lumínica, coincide con la temporada alta de turismo en el verano; las notificaciones de incidencias por picaduras de medusa en esta época son frecuentes. Ejemplo de ello, es el caso de Denia (Alicante, España) donde, desde 2008, se ha detectado un considerable aumento de incidencias sanitarias a causa de picaduras de medusa, paralela a la aparición de la especie invasora de cubomedusa Carybdea marsupialis (Bordehore et al, 2011). En este estudio se ha realizado una valoración económica de la playa como un bien ambiental recreativo, mediante encuestas semi-estructuradas elaboradas por Paulo Nunes (CIESM), aplicadas a una muestra inicial de 300 individuos; y evaluado cual sería el impacto social y económico en la valoración ambiental de Denia, si las proliferaciones de medusa no se estabilizaran. Se ha estimado el valor económico del impacto sicial causado por las bioinvasiones marinas en las playas recreacionistas según Nunes and Van den Bergh (2004) y Nunes and Markandya (2008); el método que también ha sido aplicado en el mismo estudio aplicado en Israel (B. Galil, J. Gowdy and P. Nunes 2012) y en Cataluña (2013, Paulo Nunes, M. Loureiro, L. Piñol, S. Sastre, L. Voltaire). En ambos casos los resultados en el impacto económico son considerables pero menores a los esperados, al igual que en los resultados obtenidos en Denia (Alicante).
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DDT and others organochlorine insecticides are very persistent substances. Clinical symptoms of intoxication have been reported in humans, although the main problem concerning such substances is bioaccumulation and biomagnification along throphic chains, leading to contamination of top predators and humans after them. In this review these characteristics are described, as well as some aspects of the control of vector borne diseases, like leishmaniasis and malaria, which were until recently, controlled by the health authorities using DDT.
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Defining environmental chemistry is a not an easy task because it encompasses many different topics. According to Stanley E. Manahan, author of a classical textbook of Environmental Chemistry, this branch could be defined as the one centered in the study of the sources, transport, effects and fates of chemical species in the water, soil, and air environments, as well as the influence of human activity upon these processes. More recently, new knowledge emerged from the Environmental Toxicology allowed to go even deeper in the meaning of 'effects' and 'fates' of a continuous growing number of organic and inorganic species disposed in water bodies, soils and atmosphere. Toxicity tests became an important tool to evaluate the environmental impact of such species to a great number of organisms, thus allowing to set quality criteria for drinking water, sediments and biota. The state of art shows that environmental chemistry is a multi-inter disciplinary science by nature; therefore, it needs more than a limited, unique-approach and non-oriented set of data to understand the nature of natural processes. Taking all these aspects into consideration, one can say that Environmental Chemistry in Brazil is now a well established area of research within the classical areas of the Chemistry, with a large number of emerging groups as well research groups with worldwide recognition.
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The article shows how the monitoring of the water quality can be utilized in an inter-disciplinary pedagogical project involving Analytical Chemistry, Biochemistry and Microbiology making the apprenticeship more dynamic and consolidating the link between the student and the community.
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The toxic heavy metals can not be transformed in other less toxic substances as organic wastes through chemical process. Various chemistry courses at Faculty of Philosophy, Sciences and Humanities (FFCLRP/USP) use heavy metals in their experimental classes. In this context, a course were created: "Heavy Metal Wastes generated in the teaching and research laboratories: disposal or recovery" and has a specific goal to capacitate the students to define the adequate strategy for disposal or recovery of the chemical wastes, in particular heavy metals, through an interdisciplinary approaching. This course was given to 25 students during the second semester of 2000 and 2001. The environmental responsibility desired for the professional and citizen can be promoted.
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The toxicity of the major As species present in the environment justifies the effort for quantifying the element in environmental organic samples, which can vary from animal and vegetal tissues to coal and industrial residues. This paper comments about the applicability of the O2 bomb digestion, as a general procedure for all environmental organic materials. A rapid and straightforward method is suggested, which consists in burning the sample in the bomb at high O2 pressure, dissolving the vapours in diluted HNO3 and determining As in the resulting solution by atomic absorption spectrometry with electrothermal atomization. The method was applied to certified materials and plant samples.
Resumo:
The occurrence and the effects of organotin compounds (OTs) have been studied since a long time, due to their widespread use and deleterious effects. Some OTs are used as pesticides in crops, or as biocides in antifouling paints, applied in the ship hulls to avoid attachment and growth of tube worms, mussels and barnacles. However, "nontarget" organisms may be exposed, resulting in the poisoning of biological system, originating mutations and sentencing species to extinction. In this work we reported a revision study on the history of OTs and the techniques developed for its assessment and control.