Um banho termostático de baixo custo (temperatura ambiente até 0ºC)

Thermal baths to decrease ambient temperature are an indispensable tool for most research and teaching laboratories, especially those in tropical or equatorial regions. A simple and inexpensive thermal bath has been developed based on a scratched compressor. It has three possible setups for cooling: sample immersed into the bath, sample flowing through the bath, and cooling liquid flowing in a jacket around the sample. It has been tested for 40 months. The temperature ranges from room temperature to 0 °C, when using water. The repeatability is better than 3% and the precision varies from 0.5% to 2%.

Fármacos no meio ambiente

Pharmaceutical drugs have been detected in sewage treatment plants, surface waters, underground waters and potable waters. Some investigations have been conducted in several countries such as Germany, Brazil, Canada, United States, The Netherlands, England and Italy. Patients and animals excrete part of pharmaceuticals used for human and veterinary medicine after administration in domestic sewage or on the soil. Drugs residues which have not been completely removed during passage through a sewage treatment plant (STP) enter the aquatic environment. The effects of such residual drugs in terrestrial and aquatic organisms are scarcely known.

O comportamento do metilmercúrio (metilHg) no ambiente

Methylmercury is the most hazardous mercury species known. Due to its high stability, lipid solubility, and ionic properties, this compound shows a high ability to cross membranes in living organisms, damaging the central nervous system, mainly the brain, and the effects of chronic poisoning are progressive. In this paper some aspects related to the toxicity and the cases of methylmercury poisoning are described. Other aspects related to the behavior of methylmercury and the environmental factors that influence the transformation of mercury in the water and sediment, with emphasis on the methylation/demethylation reactions and the mercury cycle are discussed.

Desreguladores endócrinos no meio ambiente: efeitos e conseqüências

There is an increasing interest in micropollutants in the environment that can interfere with the endocrine system, affecting health, growth and reproduction of animals and humans. These substances are known as Endocrine Disrupting Chemicals (EDCs) and can be found in domestic sewage, domestic wastewater treatment plant effluents, and in natural and potable waters. There are numerous chemicals classified as EDCs, such as pesticides, chemicals used and produced by chemical industries and natural and synthetic estrogens. EDCs can be related to the increase of the incidence of anomalies in the reproductive system of animals, cancer in humans and reduction of the masculine fertility.

Interferentes endócrinos no ambiente

Although the hypothesis that environmental chemicals may exhibit endocrine disrupting effects is not new, the issue has been a growing level of concern due to reports of increased incidences of endocrine-related disease in humans, including declining male fertility, and more significantly, to adverse physiological effects observed in wildlife where cause and effect relationships are more evident. The list of endocrine disrupting chemicals (EDCs) includes a range of anthropogenic compounds, phytoestrogens, naturally occurring sex steroids and synthetic estrogens. Within the aquatic environment, the presence of EDCs has concerned many scientists and water quality regulators. Discharge of effluents from treatment facilities is likely to be a significant source of input of contaminants to many systems, and the potential for concentration of hydrophilic compounds and transformation products within sludges has implications for their disposal. Then, understanding the processes and the fate of EDCs on the environment, as well as the mechanisms of endocrine disruption, may facilitate controlling or limiting exposure of both humans and the environment to these compounds.

Visões de meio ambiente e suas implicações pedagógicas no ensino de química na escola média

This study was realized with high school Chemistry teachers from the region of and around Florianópolis (SC). It examines the pedagogical implications of these teachers' views on environmental issues, and discusses the possibilities and difficulties of bringing these issues into the Chemistry classroom. The semi-structured interviews were analyzed using Textual Discourse Analysis principles. The dominance of content-based teaching and traditional pedagogical approaches appears to hinder curricular changes. Most subjects pay little heed to environmental issues and their relation to Chemistry, and endorse a view of science as neutral, and the environment as anthropocentric - views far from Green Chemistry principles.

Visões de ciências de professores de química: a mídia e as reflexões no ambiente escolar no nível médio de ensino

The present paper discusses the influence of TV and general media on students scientific ideas and the teacher's perception of this influence on students during class time. 17 high-school chemistry teachers with teaching degree, working in state schools, were interviewed. The interviews showed that both, teachers and students, have a positive opinion of science and the scientist. According to their teachers, students' positive view of science is greatly influenced by TV. The developed study shows how important epistemology is in teachers' college formation to offer them a critical perception of science treated in general media.

Energia, meio ambiente e economia: o Brasil no contexto mundial

The cycle of fossil fuels as an energy source for mankind is approaching its end. Finite resources, coupled with greenhouse gas, have led to an increased effort in the search for alternative renewable energy sources. Brazil has a leading position, due to a 46% participation of renewable sources in its primary energy supply, compared to the global average of 12%. The expansion of the renewable sources in Brazil depends on medium and long term planning, and a large volume of investments. The present financial crisis will have major effects in the energy market. Despite a negative initial impact, it is expected that the rearrangement of the financial system will ultimately lead to an expansion in the use of renewable energy sources. Brazil is a tropical country, with the largest biodiversity in our planet and excellent conditions to expand the use of all forms of renewable sources.

Tintas anti-incrustantes de terceira geração: novos biocidas no ambiente aquático

Antifouling agents have been used on vessels and boats since ancient civilizations. Thus, a brief history on the three generations of antifouling paints was provided in the present review. Additionally, information about physic-chemical properties, environmental levels, toxicology and analytical methods was discussed for the 16 "new" booster biocides used as third-generation antifouling paints. The main problems, limitations and future trends related to this subject were also presented. Finally, actions were suggested in order to appraise the current status of the environmental impact caused by these compounds in South America.

Uso de materiais recicláveis na determinação gravimétrica de CO2 no ar ambiente e tratamento dos resíduos de laboratório gerados

An alternative system was tested for the determination of CO2 in air using recyclable materials. The results indicate that the proposed system allows for reliable, accurate, robust and efficient collection, comparable to the standard gravimetric method. Laboratory wastes are easily treated using a filtrate that can be discharged into the sewer and solids that can be reused. The proposed system is a simple and low-cost tool that encompasses important aspects of environmental education, which should be part of the education in chemistry of undergraduate students and technicians.

Patenteamento em nanotecnologia no Brasil: desenvolvimento, potencialidades e reflexões para o meio ambiente e a saúde humana

Nanotechnology developments continue to be produced at exponential rates for a wide and diverse range of applications. In this paper was done a study of technological forecasting in nanotechnology applied to health, based on information drawn in Brazil from 1991 to 2010. The longitudinal evolutions of the number of patent applications, their topics, and their respective patent families have been evaluated for the total global activity. There were obtained 1352 patent applications in this period. It were analyzed the legal nature of the depositors, the year of deposit, depositors' home countries and processes. It has been a goal subsidizes the policy-makers to adapt and modernize the regulatory framework on nanotechnology and risks involving health as a strategic area in the politics of Science.

Condições de ambiente favoráveis à germinação e à infecção de Puccinia substriata var. penicillariae em diferentes cultivares de milheto pérola

A ferrugem do milheto (Pennisetum glaucum), causada por Puccinia substriata var. penicillariae, provoca perdas na produção da forragem. Tendo em vista a escassez de informações sobre a doença no Brasil realizou-se o presente trabalho sobre a sua epidemiologia. Avaliaram-se, em casa-de-vegetação, o período latente médio, a freqüência de infecção e tamanho das lesões da ferrugem em quatro genótipos de milheto: ENA 1, Composto II, BRS 1501 e HKP. In vitro, monitorou-se a germinação dos urediniósporos em diferentes temperaturas (10, 15, 20 e 25ºC), na presença ou não de luz. Após isto, avaliou-se o processo de infecção nos genótipos Guerguera, Souna III, BRS 1501 e ENA 1, em câmara de crescimento, utilizando-se 0, 1, 2, 4, 8 e 12 h de molhamento foliar, na presença ou não de luz, e em casa-de-vegetação, nos genótipos ENA 1, Guerguera e Souna III, utilizando-se 3/4, 1, 2, 4, 6 e 8 h de molhamento foliar. O período latente médio da ferrugem do milheto variou entre 10 e 12 dias, e os urediniósporos germinaram em faixa ampla de temperatura, de 10ºC a 25ºC, na presença ou não de luz, com germinação máxima a 17,5ºC no escuro. Nestas condições, os primeiros esporos germinaram com menos de 45 min. e atingiram taxa máxima, 88,2%, em 1,7 h de incubação. Infecções de folhas foram observadas em plantas submetidas a apenas 45 min de molhamento foliar após a inoculação, porém, com efeito benéfico do escuro e do aumento do período de molhamento foliar.

Evolución el añublo del arroz en dos condiciones de fertilidad nitrogenada

Con el objetivo de evaluar la evolución de la infección producida por Pyricularia oryzae (cooke) Sacc, en la hoja y en la panícula, fueron seleccionados tres genotipos de arroz (Oryza sativa). Los genotipos: El Paso 144 (EP), Don Ignacio (DI) y H 316-1-2-1-1 (H 316) fueron sembrados en condiciones de campo, en la Estación Experimental La Plata, y en dos condiciones de disponibilidad de nitrógeno (testigo o sin nitrógeno y 150 kg N ha-1 en forma de urea). El hongo fue inoculado en la tercera hoja, con una mezcla de razas, a una concentración de 1,2 x 10(5) fragmentos de hifa/ml, incubándose durante 48 horas en cámara húmeda. Fueron evaluados la severidad y tipo de mancha en la hoja y la severidad e incidencia en la panícula. Se realizó el ANOVA, y las diferencias estadísticas fueron analizadas a través del test Tukey (p<0,05). Fueron aplicados modelos Log-lineares para datos no paramétricos. No se observó interacción entre genotipo y fertilización, en las hojas, en los estadios de primer perfilo (M) y diferenciación (D). La fertilización aumentó la severidad en las hojas. El coeficiente de correlación entre el tipo de mancha y el porcentaje de severidad en la hoja fue elevado. Fue observada interacción entre genotipo y fertilización en los valores de severidad en la panícula, los mismos que disminuyeron con la fertilización en los genotipos EP y DI, pero no presentaron diferencias en H 316.

Fungos associados às sementes (Cariopses) de cana-de-açúcar: métodos para detecção, incidência e relação entre incidência fúngica e ambiente de produção das sementes

O presente trabalho teve como objetivos: determinar o método mais adequado para detecção e identificação de fungos associados às sementes (cariopses) de cana-de-açúcar; caracterizar os fungos associados; verificar as incidências nessas sementes e relacionar a incidência fúngica nessas sementes com o ambiente onde foram produzidas. Para detecção do método mais adequado, foram comparados dois substratos, em placas de Petri: agar-água com papel quadriculado e papel de filtro. Utilizaram-se placas de Petri de plástico e de vidro do tipo pirex, para verificar a influência do recipiente. Também foram comparados dois regimes de luz (12 h luz branca fluorescente/12 h escuro e escuro contínuo). As sementes foram mantidas durante sete dias sob temperatura constante de 28 2ºC, quando se procedeu à avaliação. Os requisitos para comparação dos métodos foram sensibilidade, economicidade e praticidade. A partir do método determinado como o mais adequado, foi realizada análise sanitária de 29 cruzamentos dos anos de 2002, 2003 e 2004, caracterizando os fungos associados e verificando as incidências. Posteriormente, compararam-se estas incidências com as condições ambientes, de temperatura e umidade relativa, em que as sementes foram produzidas no programa de melhoramento genético. O método considerado mais adequado, de acordo com os parâmetros analisados, foi o do papel de filtro em placa de Petri de plástico e incubação sob regime de luz (12 h luz branca fluorescente/12 h escuro). Os fungos detectados foram: Alternaria alternata; Aspergillus sp.; Bipolaris sacchari; três grupos morfológicos distintos pertencentes ao gênero Bipolaris; dois grupos morfológicos de Cladosporium; Colletotrichum sp.; três grupos morfológicos de Curvularia; Epicoccum sp.; Fusarium verticillioides; Fusarium semitectum; Leptosphaerulina sp.; Nigrospora sp.; Penicillium sp.; Periconia sp.; Phoma herbarum; Rhizopus sp. e Trichoderma sp. Os mais freqüentemente encontrados foram: Bipolaris sacchari; Bipolaris spp.; Cladosporium spp.; Curvularia spp.; Fusarium verticillioides; Fusarium semitectum e Phoma herbarum. Quando se comparou a porcentagem de incidência dos diversos fungos com o ambiente de produção das sementes, observou-se que não houve relação de temperatura e umidade relativa com incidência fúngica. Supõe-se que as variações de incidência possam estar relacionadas com diferentes fontes de inóculo nos locais de cruzamento ou características genéticas das sementes.