BIOLOGIA FLORAL E VIABILIDADE DE PÓLEN EM CULTIVARES DE CAQUIZEIRO (Diospyros kaki L.) E Diospyros virginiania L.

RESUMO O caquizeiro é uma planta muito complexa na questão de sua biologia floral, já que pode apresentar três tipos de flor (feminina, masculina ou hermafrodita) ou apenas flores femininas, como no caso das cultivares comerciais. O objetivo deste trabalho foi estudar o período de florescimento, os tipos de flores e estimar a viabilidade dos grãos de pólen em nove cultivares de D. kaki e em D. virginiana. As cultivares Pomelo e Rama Forte foram precoces para o início do florescimento. A cultivar Pomelo e a espécie D. virginiana apresentaram produção de flores masculinas, com pólen viável. As nove cultivares de D. kakiestudadas apresentaram produção de flores femininas (também masculinas em Pomelo) como esperado em cultivares comerciais. Porém a cultivar Mikado apresentou, ao final do florescimento, flores com produção de pólen viável, o que ainda não havia sido relatado. A viabilidade dos grãos de pólen, em geral, foi acima de 90% para as cultivares Pomelo e Mikado, e para D. virginiana.

Biologia, religiositat i rituals (i II)

La religiositat pot actuar de mecanisme de cohesió, però sobretot a nivell de societats tribals on tots pertanyen a la mateixa comunitat

Espectacular avenç de la biologia sintètica

L'avenç fet pel grup de Jef Boeke és importantíssim, un salt de la biologia sintètica, però cal evitar interpretacions errònies, falses esperances i temors.

Lista de recomendações do Exame PET/CT com 18F-FDG em Oncologia: consenso entre a Sociedade Brasileira de Cancerologia e a Sociedade Brasileira de Biologia, Medicina Nuclear e Imagem Molecular

Apresentamos uma lista de recomendações sobre a utilização de 18F-FDG PET em oncologia, no diagnóstico, estadiamento e detecção de recorrência ou progressão do câncer. Foi realizada pesquisa para identificar estudos controlados e revisões sistemáticas de literatura composta por estudos retrospectivos e prospectivos. As consequências e o impacto da 18F-FDG PET no manejo de pacientes oncológicos também foram avaliados. A 18F-FDG PET deve ser utilizada como ferramenta adicional aos métodos de imagem convencionais como tomografia computadorizada e ressonância magnética. Resultados positivos que sugiram alteração no manejo clínico devem ser confirmados por exame histopatológico. A 18F-FDG PET deve ser utilizada no manejo clínico apropriado para o diagnóstico de cânceres do sistema respiratório, cabeça e pescoço, sistema digestivo, mama, melanoma, órgão genitais, tireoide, sistema nervoso central, linfoma e tumor primário oculto.

Conhecimento escolar em química: processo de mediação didática da ciência

xThe aim of this article is to present a contribution of the school knowledge research to Chemistry Teaching. The object of research is school knowledge on physical sciences, considering the existence of a rupture between scientific knowledge and everyday knowledge. The differences between analogies and metaphors and the process of didactic mediation were thoroughly examined. The conclusion is that the process of didactic mediation is built on their own cognitive configurations, which not always make public the private scientific knowledge to certain social groups.

Química geral experimental: uma nova abordagem didática

This essay describes a new didactic approach, in according with the national curriculum guidelines for chemistry undergraduate courses in Brazil, employed during the one-semester course "Experimental General Chemistry" for chemistry undergraduate students at the Federal University of Piauí. The new approach has positively helped student's training by improving their reading skills and their understanding of scientific reports, by developing the use of electronic tools to search and to recover the required knowledge for their learning activities, and by improving their skills of understanding published texts and dealing with digital sources. At the same time the students are strongly stimulated to enter the research program for undergraduate students available at the University.

La biologia del racisme

El racisme és una xacra que afecta a totes les societats. És un concepte que apliquem a contextos diferents, des de la discriminació en funció de l'origen personal, que deduïm a partir de la fesomia, fins a l'aversió, i que sovint es veu reflectit també en sentiments de superioritat cultural i moral. Parlar de racisme, però, presenta una paradoxa atès que en la població humana no hi ha races en el sentit biològic de la paraula [...].

La biologia està de dol

Aquest estiu ens han deixat tres grans científics que van centrar la seva recerca en l'origen i el funcionament de la vida: Francis Crick, codescobridor de l'estructura del DNA; Edward Lewis, pioner en la recerca de gens que controlen el desenvolupament embrionari, i Joan Oró, que va estudiar els orígens de la vida [...].

Biologia química: uma estratégia moderna para a pesquisa em produtos naturais

This paper presents an overview of the Natural Products Research in Brazil in the last five years (2002-2006), and also discusses how some relevant aspects of the Chemical Biology area could create new research opportunities and challenges for the natural product chemists. In addition, some aspects of the scientific policies and their impact on current projects are discussed.

I2: uma molécula didática

Iodine vapor is a very suitable substance to learn about molecular energy levels and transitions, and to introduce spectroscopic techniques. As a diatomic molecule its spectra are relatively simple and allow straightforward treatment of the data leading to the potential energy curves and to quantum mechanics concepts. The overtone bands, in the resonance Raman scattering, and the band progressions, in the electronic spectra, play an important role in the calculation of the Morse potential curves for the fundamental and excited electronic state. A weaker chemical bond in the electronic excited state, compared to the fundamental state, is evidenced by the increase in the equilibrium interatomic distance. The resonance Raman scattering of I2 is highlighted due to its importance for obtaining the anharmonicity constant in the fundamental electronic state.

D-aminoácidos em biologia: mais do que se julga

It is still frequently referred, even in reference text-books, that the D-enantiomers of amino acids are not present in living organisms, which is not right. In the present revision/informative paper we describe a large number of D-amino acids that are present in all forms of organisms, from bacteria to human beings, in the free state, in peptides and in proteins, and give a short overview of their characteristics, physiological interaction and roles.

Sistemas tampão: uma estrutura didática teórico-prática

Courses with practical and theoretical classes are potentially didactic structures for the development of motor and complex cognitive skills when operated in an integrated manner. When worked aligned, theory and practice enable a clearer view of the issue, opening scope for introducing concepts from other disciplines and for the development of lab skills. This paper presents a methodology for biochemistry labwork that promotes the teaching of the buffering systems contents together with to the development of scientific research practice concepts in an interdisciplinary perspective that integrates theory and practice.

Uma experiência didática de corrosão usando colorimetria visual

In this paper, a simple and rapid method of evaluating galvanized steel sheet corrosion in a CuSO4 solution, as an experimentation proposal for corrosion teaching. Galvanized steel corrosion is present in tanks and tubing by leading of natural or industrial waters which contain soluble copper compounds. This was the rationale for choosing the Cu2+ ions solution as an oxidizing agent. The method principle is based on visual colorimetry because the used oxidant has an intense blue color. Thus, a change in its concentration as a result of the corrosive process can be followed by a color intensity change in the solution thereby allowing evaluation of the corrosion rate.

Reações multicomponentes de Biginelli e de Mannich nas aulas de química orgânica experimental: uma abordagem didática de conceitos da química verde

The introduction of Mannich and Biginelli multicomponent reactions in a practical Organic Chemistry course is presented in this article. Procedures described in the literature were adapted for use under the simple conditions available in undergraduate laboratories and were selected on the basis of Green Chemistry principles and practicality of synthesis. The reactions are easy to carry out and all products are readily isolated as crystalline solids with yields ranging from moderate to high.