Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Biochem Mol Biol Educ ; 49(2): 198-209, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32823370

RESUMO

Nowadays Molecular Cell Biology (MCB) must be taught as science is practiced. Even though there are several approaches based on scientific practices, a key aspect is to define the purpose of each of these teaching strategies and, most importantly, their implementation. Our goal was to train students to acquire, understand, and communicate new scientific knowledge in the field. The main feature of our new teaching methodology was progressive training in scientific practices associated with a back-and-forward interplay between activities and assessments. The methodology was implemented over 4 years, in students attending the MCB course of the undergraduate degree in Biological Sciences. In the first two modules, the students were prepared to comprehend MCB concepts and techniques and to experience activities based on scientific practices. In the third module, the students analyzed a primary paper in-depth. They were assessed by midterm exams based on a primary paper, written laboratory reports, and the oral presentation of a scientific paper. Our teaching proposal was evaluated through the students' academic performance and by their opinion on the teaching methodology. Most students were satisfied since they improved their acquisition of concepts, their interpretation and integration of scientific knowledge, and developed skills to communicate scientific knowledge in writing and orally. The novelty of transversal interconnections and progressive training in scientific practices provides students with skills in acquiring and understanding new scientific information, even beyond the MCB course.


Assuntos
Biologia Celular/educação , Avaliação Educacional , Biologia Molecular/educação , Estudantes , Humanos
2.
J Hazard Mater ; 213-214: 447-56, 2012 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-22390956

RESUMO

The objectives of this study were to determine the average concentrations and deposition rates of 28 elements in atmospheric bulk deposition and to elucidate associations among topsoil, bulk deposition and wheat element composition. The fluxes of arsenic (As), copper (Cu), lead (Pb) and zinc (Zn) deposition in Córdoba were higher than in other agro-ecosystems, which reflects both natural (geochemistry and topsoil removal) and anthropogenic sources. High lanthanide, uranium (U) and thorium (Th) concentrations revealed the impact of an open cast uranium mine. The highest enrichment factors (EF) were those of Cu, Pb, Zn and nickel (Ni), with calcium (Ca) being the most prominent in the surroundings of a cement plant. Industries and the transport of airborne urban pollutants were the main anthropogenic sources for Ca, Cu, Ni, Pb, Zn, cadmium (Cd), iron (Fe), manganese (Mn) and antimony (Sb). The concentrations of metals in wheat grain were predicted using the topsoil and atmospheric fall-out composition with R(2)=0.90, with the latter being the best explanatory variable. The present study highlights the potential health hazards of wheat consumption (Environmental Protection Agency) by the assessment of heavy metals in bulk atmospheric deposition.


Assuntos
Poluentes Ocupacionais do Ar/análise , Metais Pesados/análise , Poluentes do Solo/análise , Solo/análise , Oligoelementos/análise , Triticum/química , Argentina , Interpretação Estatística de Dados , Elementos Químicos , Monitoramento Ambiental , Ácido Clorídrico , Indicadores e Reagentes , Ácido Nítrico , Caules de Planta/química , Controle de Qualidade , Análise de Regressão , Sementes/química , Espectrofotometria Atômica
3.
J Hazard Mater ; 193: 264-71, 2011 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-21835546

RESUMO

Heavy metal and trace element concentrations were examined in wheat grains and straw to elucidate associations between air pollution sources and soil variables. The mean wheat grain concentrations of Cr, Cu, Fe, Mn and Zn surpassed the tolerance limits stated in the international legislation for wheat grain and foodstuffs. When topsoil Ba, Co, Cr and Zn concentrations were higher than the legislation thresholds for agricultural and residential soils, wheat grain concentrations were also increased. In addition, Cr, Cu, Mn, Ni, Pb, and Zn revealed an immobilization effect of a cement plant and the atmospheric deposition input, with Cd in wheat grains being associated with a cement plant and industrial waste incinerator. The health risks arising from wheat grain consumption indicated that the inhabitants of Argentina are experiencing significant non-carcinogenic risks (Hazard Index = 3.311), especially when consuming wheat grains affected by metallurgical or chemical factories, as well as by air transportation from big cities.


Assuntos
Exposição Ambiental , Metais Pesados/análise , Oligoelementos/análise , Triticum/química , Carcinógenos/toxicidade , Metais Pesados/toxicidade , Análise de Ativação de Nêutrons , Controle de Qualidade , Espectrofotometria Atômica , Oligoelementos/toxicidade
4.
Arch Environ Contam Toxicol ; 61(3): 401-13, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21279718

RESUMO

To evaluate the physiological response of Tillandsia capillaris Ruiz & Pav. f. capillaris, T. recurvata L., and T. tricholepis Baker to different air pollution sources, epiphyte samples were collected from a noncontaminated area in the province of Córdoba (Argentina) and transplanted to a control site as well as three areas categorized according to the presence of agricultural, urban, and industrial (metallurgical and metal-mechanical) emission sources. A foliar damage index (FDI) was calculated with the physiological parameters chlorophyll a, chlorophyll b, malondialdehyde (MDA), hydroperoxyconjugated dienes, sulfur (S) content, and dry weight-to-fresh weight ratio. In addition, electrical conductivity (E-cond), relative water content (RWC), dehydration kinetics (Kin-H(2)O), total phenols (T-phen), soluble proteins (S-prot), and activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase were determined. The parameters E-cond, FDI, SOD, RWC, and Kin-H(2)O can serve as suitable indicators of agricultural air pollution for T. tricholepis and T. capillaris, and CAT, Kin-H(2)O, and SOD can do the same for T. recurvata. In addition, MDA, T-phen, and S-prot proved to be appropriate indicators of urban pollution for T. recurvata. Moreover, FDI, E-cond, and SOD for T. recurvata and MDA for T. tricholepis, respectively, could be used to detect deleterious effects of industrial air pollution.


Assuntos
Poluição do Ar/efeitos adversos , Antioxidantes/metabolismo , Monitoramento Ambiental/métodos , Tillandsia/química , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Argentina , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Clorofila/análise , Clorofila A , Malondialdeído/análise , Folhas de Planta/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Enxofre/análise , Superóxido Dismutase/metabolismo , Tillandsia/efeitos dos fármacos , Tillandsia/crescimento & desenvolvimento
5.
Chemosphere ; 78(4): 375-81, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19962174

RESUMO

Heavy metal and trace element concentrations were examined in topsoils to evaluate a cement plant and an industrial waste incinerator as pollution sources. As, Ba, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Se, Sm, Ta, Tb, Th, U, Yb and Zn were measured by Neutron Activation Analysis (NAA), and Co, Cu, Fe, Ni, Pb and Zn by a 0.5M-hydrochloric extraction technique using an Atomic Absorption Spectrophotometer (AAS). The Cr total concentration and HCl-extracted Co and Mn were possibly related to wind transportation from an industrial area in the north of Córdoba city (Argentina). Cu, Pb and Zn in partial HCl extraction were influenced by the cement plant and the industrial area in the north of Córdoba city. The mean total Ba concentration was above the residential and agricultural land use limits stated in national and international legislation and was related to the distance to the cement plant. The concentrations of HCl-extracted heavy metals could be predicted by the organic matter percentage and the distance to the cement plant (with R(2) values of 0.50-0.74). The Ca total concentration was seen to have little influence whereas the organic matter percentage strongly affected HCl-extracted heavy metals according to the correlation analysis and multiple regression models. According to soil quality guidelines for environmental health, the human and wildlife populations in Yocsina might be experiencing toxic Ba and Cr effects.


Assuntos
Resíduos Industriais/efeitos adversos , Indústrias/tendências , Metais Pesados/análise , Poluentes do Solo/análise , Oligoelementos/análise , Argentina , Humanos , Metais Pesados/toxicidade , Valor Preditivo dos Testes , Solo , Poluentes do Solo/toxicidade , Oligoelementos/toxicidade
6.
Environ Res ; 109(1): 6-14, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18951124

RESUMO

Bioaccumulation ability and response to air pollution sources were evaluated for Tillandsia capillaris Ruíz and Pav. f. capillaris, T. recurvata L., T. tricholepis Baker and the lichen Ramalina celastri (Spreng.) Krog. and Swinsc. Epiphyte samples collected from a non contaminated area in the province of Córdoba were transplanted to a control site and three areas categorised according to agricultural, urban and industrial (metallurgical and metal-mechanical) emission sources. Bioindicators were exposed for 3-, 6- and 9-month periods. A foliar damage index was established for Tillandsia and a pollution index for the lichen, and S, Fe, Mn and Zn concentrations were determined. An order of efficiency for the species and conditions studied is proposed taking into account heavy metal accumulation: T. recurvata >T. tricholepis >R. celastri >T. capillaris. All species studied showed Mn to be related to agricultural activity and Fe to industries and soil particles, and Zn was related to urban and industrial sources. As far as physiological response is concerned, T. tricholepis and T. capillaris were more sensitive to agricultural activities, whereas T. recurvata was sensitive to urban and industrial sources, and only partially to agricultural sources. No relationship was found for R. celastri.


Assuntos
Poluição do Ar/análise , Monitoramento Ambiental/métodos , Líquens/química , Tillandsia/química , Argentina , Líquens/fisiologia , Metais Pesados/análise , Estações do Ano , Especificidade da Espécie , Tillandsia/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...