606 research outputs found

    Clypeina tibanai, sp. nov. (Polyphysaceae, Dasycladales, Chlorophyta), a mid-Cretaceous green alga from the Potiguar Basin, Brazilian margin of the young South Atlantic Ocean

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    The fossil genus Clypeina (Michelin, 1845) comprises some 40 species. We describe Clypeina tibanai, a new spe-cies from ? upper Albian–Cenomanian strata of the Potiguar Basin, Brazil, characterised by closely set verticils of tubular, bended laterals. It is compared with Clypeina hanabataensis Yabe & Toyama, 1949, a Late Jurassic species, and with Pseudoactinoporella fragilis (Conrad, 1970), an Early Cretaceous taxon. The new species be-longs to a short list of green algae found in the young South Atlantic oceanic corridor, an assemblage defining a phycological paleobioprovince discrete from that of the Tethyan realm

    Radiocarbon and blue optically stimulated luminescence chronologies of the Oitavos consolidated dune (Western Portugal)

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    The dune of Oitavos, the underlying paleosol, and Helix sp. gastropod shells found within the paleosol were dated using a combination of radiocarbon and blue optically stimulated luminescence (OSL). The organic component of the paleosol produced a significantly older age (~20,000 cal BP) than the OSL age measurement (~15,000 yr), while 14C age measurements on the inorganic component and the gastropods produced ages of ~35,000 yr and ~34,000 yr, respectively. Rare-earth element analyses provide evidence that the gastropods incorporate geological carbonate, making them an unreliable indicator of the age of the paleosol. We propose that the 14C age of the small organic component of the paleosol is also likely to be unreliable due to incorporation of residual material. The OSL age measurement of the upper paleosol (~15,000 yr) is consistent with the age for the base of the dune (~14,500 yr). The younger OSL age for the top of the dune (~12,000 yr) suggests that it was built up by at least 2 sand pulses or that there was a remobilization of material at the top during its evolution, prior to consolidation

    Acetylcholinesterase inhibitory activity of oxazole derivatives

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    Comunicação oral sob a forma de painelAlzheimer’s disease (AD) is the most common form of dementia among persons over 65 years of age. It is a brain neurodegenerative disorder characterised by loss of memory and cognition. Current treatment is symptomatic, with the major therapeutic strategy based on the “cholinergic hypothesis”, specifically acetylcholinesterase (AChE) inhibition. Tacrine (THA) was the first and one of the few drugs approved in the last decade for the treatment of AD. However, due to the important adverse effects, such as hepatotoxicity, it is no longer widely used. Therefore, more potent and less aggressive THA analogues are necessary. This prompted us to evaluate the AChE inhibitory activity of new oxazole derivatives (compounds 1-5), presenting a pyridine ring (compounds 2,3) or a benzene ring (compounds 4,5) in the molecule (1). The biological activity of the compounds was evaluated by measuring the AChE inhibitory activity by an adaptation of the method reported by Ellman et al (2). The reaction rates were compared and the percent of inhibition by the test compounds was calculated. Assays were performed in quadruplicate in at least two independent experiments, and THA was used as a reference compound. At the maximum soluble concentrations, compounds 1 and 2 inhibited AChE activity by nearly 50%, while the inhibition by the derivative 3 was only around 30%. In contrast, the oxazolo-derivatives 4 and 5 were devoid of any inhibitory activity, which we can speculate to be due to the absence of the N atom in the benzene ring in these compounds. Collectively, these preliminary findings point to a potential interest of precursor 1 and THA-derivative 2 for AD therapeutics, although structural modifications are needed to improve the solubility of the compounds, which is an essential step to enhance their activity. References: 1. Carreiras MC, Eleutério A, Marco-Contelles J, unpublished results. 2. Ellman, G. L. et al. Biochem. Pharmacol. 1961; 7: 88-95.Financial support: Centro de Estudos de Ciências Farmacêuticas, Centro de Patogénese Molecular – UBMBE and Instituto de Química Orgánica General – CSIC

    To practice or not to practice? Designing higher education curriculum to boost employability

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    One important dimension of Higher education curriculum design pertains to the inclusion of internships in study programmes. These have been generally conceptualized as learning experiences capable of bridging theoretical knowledge and hands-on experiences. The underlying pedagogical relevance is based on the premise that internships create the possibility of contextualized learning, fostering both professional growth and students’ self-esteem and pro-activity (Little, 2006). Interns are provided with the opportunity of early networking, as they enrol in practical activities and professionally interact with other people, besides their academic teachers and their graduate colleagues (Alpert, Heaney, & Kuhn, 2009; Weible, 2009). Research concerning internships has extensively reported the overwhelming positive effect of internships. Nevertheless, a more recent trend in literature has argued that little has been said concerning the relationship between internships and graduate employment or employability. Wilton (2012), for example, argues that more needs to be understood about the characteristics and specificities of internships and the extent to which such characteristics are capable of overcoming the current concern over the increase of graduates’ unemployment rates. Research conducted on the Portuguese case based on a database of 1,168 study programmes of first cycle degrees sough to redress this gap. Besides demonstrating that study programmes which include internships (cooperative education) tend to generate lower levels of unemployment than those that do not include internships, this research has suggested that the nature and structure of internships significantly impacts on graduate unemployment rates. In specific, mandatory internships tend to outperform their optional counterpart in reducing graduate unemployment levels. Moreover, thin sandwich courses also seem to be more beneficial than thick sandwich courses, suggesting that expanding and diversifying internships throughout the curriculum can reduce graduate unemployment rates. These results strongly suggest that it is not (only) the internship learning experience per se that makes the difference considering graduate employability, but (also) the way those internship experiences are organized along the study programme. This poster is, thus, focused on the nature and structure of internships, assessing their implications for higher education curriculum design. It does so by exploring the perspectives of the main stakeholders involved in internships regarding their motivations; required efforts; and expected outcomes. Empirically, the poster is based on the content analysis of semi-structured individual interviews to units coordinators and also focus groups conducted with coordinators of study programmes; internship supervisors (both academics and employers); and also interns. Qualitative analysis has been sustained by the main learning models traditionally used in research on work-based learning and aims at identifying a set of principles related with internships design, and modes of embedding them along an entire course, which may contribute to the development of graduates’ employability. Reported findings may constitute an important primer for reflection on the design of pedagogical strategies that maximize the contextual learning outputs of internships in a more systematic way, being particularly relevant for leading academics, namely those involved in curriculum design

    Métodos preventivos contra agentes contaminantes em cultura de células primárias de Membrana Sinovial Caprina.

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    Objetivou-se com este estudo descrever métodos preventivos contra contaminação em cultura celular primária de Membrana Sinovial Caprina (MSC) adotados no Laboratório de Virologia da Embrapa Caprinos e Ovinos, Sobral-CE, e demonstrar a sua importância dentro de um laboratório de cultura de células

    Estimação de parâmetros genéticos e avaliação de genótipos de melancia.

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    O presente trabalho teve como objetivo estimar parâmetros genéticos e avaliar genótipos do programa de melhoramento de melancia conduzido pela Embrapa Semiárido

    Uso de técnicas multivariadas na seleção de genitores potenciais para desenvolvimento de populações de melancia de sementes pequenas.

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    O presente trabalho objetivou avaliar a divergência fenotípica de acessos de melancia do Banco Ativo de Germoplasma da Embrapa Semiárido, utilizando descritores quantitativos de sementes

    Correlações entre caracteres morfo-agronômicos de melancia.

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    O presente trabalho teve como objetivo avaliar as correlações entre características morfo-agronômicas avaliadas em diferentes cultivares de melancia
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