1,212 research outputs found

    O que estå em jogo no confronto entre criacionismo e evolução

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    Lidar com o embate entre perspectivas criacionistas e evolucionis-tas Ă© parte da realidade de muitos professores de biologia. Neste ensaio buscamos caracterizar esse confronto, sugerindo que ele nĂŁo pode ser carac-terizado como um “debate”. A seguir argumentamos que a perspectiva cria-cionista, quando apresentada como alternativa excludente Ă  evolução, acaba por trazer prejuĂ­zos para o ensino de ciĂȘncias que vĂŁo muito alĂ©m do ensino da biologia. No final oferecemos algumas sugestĂ”es para ajudar professores a se posicionarem diante de perspectivas criacionistas

    The concept of gene in the twenty-first century: What are the open avenues?

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    ABSTRACTThe view of the gene as a structural and functional unit has been increasingly challenged by findings mostly resulting from eukaryote research. We can classify these challenges in three kinds: (i) one-to-many correspondences between DNA segments and RNAs/polypeptides (as, for instance, in alternative splicing); (ii) many-to-one correspondences between DNA segments and RNAs/polypeptides (as in genomic rearrangements, say, those involved in the generation of diversity in lymphocyte antigen receptors); (iii) lack of correspondence between DNA segments and RNAs/polypeptides (as, for example, in mRNA editing). However, even if a single definition of a gene may not be a realistic (or even helpful) goal, being able to have different definitions connected to each other –operationally and theoretically– is of central importance.KEYWORDSGENE CONCEPT, DEFINITION, DNARESUMENLa idea segĂșn la cual el gen es una unidad estructural y funcional se ha visto cada vez mĂĄs cuestionada a causa de descubrimientos realizados en investigaciones con eucariotas. Podemos clasificar los desafĂ­os planteados a dicha idea en tres tipos: (i) correspondencias uno-a-muchos entre segmentos de ADN y ARN/polipĂ©ptidos (como, por ejemplo, en el empalme alternativo); (ii) correspondencias muchos-a-uno entre segmentos de ADN y ARN/polipĂ©ptidos (como en las reorganizaciones genĂłmicas, tales como las implicadas en la generaciĂłn de diversidad en los receptores de antĂ­genos de los linfocitos); (iii) falta de correspondencia entre segmentos del ADN y ARN/polipĂ©ptidos (como, por ejemplo, en la ediciĂłn del ARNm). Sin embargo, incluso si, por estas razones, no serĂ­a realista (o incluso Ăștil) buscar una definiciĂłn Ășnica de gen, es de capital importancia que seamos capaces de formular diferentes definiciones conectadas entre sĂ­ teĂłrica y operacionalmente.PALABRAS CLAVECONCEPTO DE GEN, DEFINICIÓN, AD

    Black Stork Down: Military Discourses in Bird Conservation in Malta

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    Tensions between Maltese hunters and bird conservation NGOs have intensified over the past decade. Conservation NGOs have become frustrated with the Maltese State for conceding to the hunter lobby and negotiating derogations from the European Union’s Bird Directive. Some NGOs have recently started to organize complex field-operations where volunteers are trained to patrol the landscape, operate drones and other surveillance technologies, detect illegalities, and lead police teams to arrest poachers. We describe the sophisticated military metaphors which conservation NGOs have developed to describe, guide and legitimize their efforts to the Maltese public and their fee-paying members. We also discuss why such groups might be inclined to adopt these metaphors. Finally, we suggest that anthropological studies of discourse could help understand delicate contexts such as this where conservation NGOs, hunting associations and the State have ended in political deadlock

    The road to a world-unified approach to the management of patients with gastric intestinal metaplasia: a review of current guidelines

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    Objective: During the last decade, the management of gastric intestinal metaplasia (GIM) has been addressed by several distinct international evidence-based guidelines. In this review, we aimed to synthesise these guidelines and provide clinicians with a global perspective of the current recommendations for managing patients with GIM, as well as highlight evidence gaps that need to be addressed with future research. Design: We conducted a systematic review of the literature for guidelines and consensus statements published between January 2010 and February 2023 that address the diagnosis and management of GIM. Results: From 426 manuscripts identified, 16 guidelines were assessed. There was consistency across guidelines regarding the purpose of endoscopic surveillance of GIM, which is to identify prevalent neoplastic lesions and stage gastric preneoplastic conditions. The guidelines also agreed that only patients with high-risk GIM phenotypes (eg, corpus-extended GIM, OLGIM stages III/IV, incomplete GIM subtype), persistent refractory Helicobacter pylori infection or first-degree family history of gastric cancer should undergo regular-interval endoscopic surveillance. In contrast, low-risk phenotypes, which comprise most patients with GIM, do not require surveillance. Not all guidelines are aligned on histological staging systems. If surveillance is indicated, most guidelines recommend a 3-year interval, but there is some variability. All guidelines recommend H. pylori eradication as the only non-endoscopic intervention for gastric cancer prevention, while some offer additional recommendations regarding lifestyle modifications. While most guidelines allude to the importance of high-quality endoscopy for endoscopic surveillance, few detail important metrics apart from stating that a systematic gastric biopsy protocol should be followed. Notably, most guidelines comment on the role of endoscopy for gastric cancer screening and detection of gastric precancerous conditions, but with high heterogeneity, limited guidance regarding implementation, and lack of robust evidence. Conclusion: Despite heterogeneous populations and practices, international guidelines are generally aligned on the importance of GIM as a precancerous condition and the need for a risk-stratified approach to endoscopic surveillance, as well as H. pylori eradication when present. There is room for harmonisation of guidelines regarding (1) which populations merit index endoscopic screening for gastric cancer and GIM detection/staging; (2) objective metrics for high-quality endoscopy; (3) consensus on the need for histological staging and (4) non-endoscopic interventions for gastric cancer prevention apart from H. pylori eradication alone. Robust studies, ideally in the form of randomised trials, are needed to bridge the ample evidence gaps that exist

    Caça de vertebrados no Parque Nacional da Serra do Divisor, Acre

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    Apesar de a caça de animais silvestres garantir a segurança alimentar de populaçÔes rurais e indĂ­genas na AmazĂŽnia, a atividade representa um desafio para a conservação da biodiversidade. Mesmo em unidades de conservação (UCs), o impacto da extração de vertebrados ainda Ă© pouco conhecido, dificultando açÔes de manejo e a implementação de estratĂ©gias de conservação adequadas Ă  realidade local. Neste trabalho, apresentamos o perfil da atividade de caça de uma comunidade tradicional do Parque Nacional da Serra do Divisor (PNSD), no sudoeste da AmazĂŽnia. AtravĂ©s de entrevistas semiestruturadas, realizadas em janeiro de 2018, e de dados originados de atividades de fiscalização desenvolvidas entre janeiro de 2016 e janeiro de 2018, identificamos que 57,9% dos 69 vertebrados com ocorrĂȘncia confirmada para a ĂĄrea de uso da comunidade PĂ© da Serra sĂŁo alvos de caça para alimentação. Cerca de um quinto das espĂ©cies ameaçadas em listas nacionais e internacionais Ă© citado como fonte de alimento. Os ungulados, aves, roedores caviomorfos, o tatu-verdadeiro (Dasypus novemcinctus) e o jabuti (Chelonoidis denticulatus) constituĂ­ram os grupos taxonĂŽmicos mais frequentemente citados e mais apreciados para consumo. Para o abate e captura de vertebrados cinegĂ©ticos, foram registrados o emprego da busca ativa, a focagem com uso de lanternas, armadilhas de arma de fogo e a espera. Os moradores da comunidade tambĂ©m utilizam a fauna silvestre para fins medicinais, como animal de estimação e na alimentação de animais domĂ©sticos. Apesar de o comĂ©rcio de produtos animais nĂŁo ter sido relatado pelos moradores, verificamos que 30,8% das missĂ”es de fiscalização realizadas no PNSD resultaram em apreensĂŁo de itens silvestres. A biomassa total interceptada foi de 428,08kg. A espĂ©cie mais registrada nas apreensĂ”es foi C. denticulatus, totalizando 37,9% do total de animais interceptados. A diversidade de espĂ©cies e os usos a elas atribuĂ­dos, revelados neste levantamento, destacam a importĂąncia do recurso faunĂ­stico para as populaçÔes humanas do PNSD. É atravĂ©s do uso de tĂ©cnicas produtivas de baixo impacto, associado a empreendimentos locais de geração alternativa de renda, e criação de mecanismos de governança local, que a biodiversidade poderĂĄ ser conservada ou mantida na regiĂŁo

    Congenital Disorders of Glycosylation in Portugal—Two Decades of Experience

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    Objective: To describe the clinical, biochemical, and genetic features of both new and previously reported patients with congenital disorders of glycosylation (CDGs) diagnosed in Portugal over the last 20 years. Study design: The cohort includes patients with an unexplained multisystem or single organ involvement, with or without psychomotor disability. Serum sialotransferrin isoforms and, whenever necessary, apolipoprotein CIII isoforms and glycan structures were analyzed. Additional studies included measurement of phosphomannomutase (PMM) activity and analysis of lipid-linked oligosaccharides in fibroblasts. Sanger sequencing and massive parallel sequencing were used to identify causal variants or the affected gene, respectively. Results: Sixty-three individuals were diagnosed covering 14 distinct CDGs; 43 patients diagnosed postnatally revealed a type 1, 14 a type 2, and 2 a normal pattern on serum transferrin isoelectrofocusing. The latter patients were identified by whole exome sequencing. Nine of them presented also a hypoglycosylation pattern on apolipoprotein CIII isoelectrofocusing, pointing to an associated O-glycosylation defect. Most of the patients (62%) are PMM2-CDG and the remaining carry pathogenic variants in ALG1, ATP6AP1, ATP6AP2, ATP6V0A2, CCDC115, COG1, COG4, DPAGT1, MAN1B1, SLC35A2, SRD5A3, RFT1, or PGM1. Conclusions: Portuguese patients with CDGs are presented in this report, some of them showing unique clinical phenotypes. Among the 14 genes mutated in Portuguese individuals, 8 are shared with a previously reported Spanish cohort. However, regarding the mutational spectrum of PMM2-CDG, the most frequent CDG, a striking similarity between the 2 populations was found, as only 1 mutated allele found in the Portuguese group has not been reported in Spain.info:eu-repo/semantics/publishedVersio

    The emerging structure of the Extended Evolutionary Synthesis: where does Evo-Devo fit in?

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    The Extended Evolutionary Synthesis (EES) debate is gaining ground in contemporary evolutionary biology. In parallel, a number of philosophical standpoints have emerged in an attempt to clarify what exactly is represented by the EES. For Massimo Pigliucci, we are in the wake of the newest instantiation of a persisting Kuhnian paradigm; in contrast, Telmo Pievani has contended that the transition to an EES could be best represented as a progressive reformation of a prior Lakatosian scientific research program, with the extension of its Neo-Darwinian core and the addition of a brand-new protective belt of assumptions and auxiliary hypotheses. Here, we argue that those philosophical vantage points are not the only ways to interpret what current proposals to ‘extend’ the Modern Synthesis-derived ‘standard evolutionary theory’ (SET) entail in terms of theoretical change in evolutionary biology. We specifically propose the image of the emergent EES as a vast network of models and interweaved representations that, instantiated in diverse practices, are connected and related in multiple ways. Under that assumption, the EES could be articulated around a paraconsistent network of evolutionary theories (including some elements of the SET), as well as models, practices and representation systems of contemporary evolutionary biology, with edges and nodes that change their position and centrality as a consequence of the co-construction and stabilization of facts and historical discussions revolving around the epistemic goals of this area of the life sciences. We then critically examine the purported structure of the EES—published by Laland and collaborators in 2015—in light of our own network-based proposal. Finally, we consider which epistemic units of Evo-Devo are present or still missing from the EES, in preparation for further analyses of the topic of explanatory integration in this conceptual framework

    Chemical and Microbiological Contamination in Limpet (Patella spp.) of the Portuguese Coast

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    Coastal production areas can be impacted by anthropogenic contamination from urban, agro-industrial and leisure activities. Some contaminants, such as chemical substances might also have a telluric origin. Non filter feeding univalve mollusks, such as limpets, which are collected in rocky shores either for sale or for auto-consumption, are very appreciated in Portugal, but have been excluded from provisions on the classification of production areas, although can present relevant contamination. Thus, the aim of this study was to assess the microbiological and toxic metal contaminations in limpets (Patella spp) of the Portuguese coast, taking into account the production area and seasonal variation, and comparing their contamination levels with those occurring in bivalve mollusk indicator species, mussel (Mytilus edulis). The risks associated to the consumption of limpet meals were also assessed. For that, microbial total and fecal levels and cadmium, lead and mercury contents in limpets and mussels samples from three coastal areas over several months were analyzed based on standard methodologies. Contents of mercury and lead in limpets from the three areas studied, were always below the limits of 0.50 mg kg-1 and 1.5 mg kg-1 allowed by the EU, respectively. Regarding cadmium, levels in limpet were always above the limit of 1.0 mg kg-1, reaching about 3.0 mg kg-1 in some samples. These values probably indicate contamination from telluric origin (soil or rocks) in the coastal studied areas. Results indicated that microbiological contamination of fecal origin was low and in general below the detection level. Contamination levels did not show a clear seasonal pattern. The two mollusk species, limpets and mussels, differed statistically in all contaminants analyzed, being cadmium the most of concern, and always higher in limpets than in mussel samples. Thus, the potential risk associated with limpet consumption, taking into account the cadmium tolerable weekly intake (TWI), was investigated, being possible to reach a reliable recommendation of less than a monthly meal of 160 g. As recreational picking of limpets is common in Portugal, official 4recommendations of maximum periodic human consumption should be published and enforcement increased in forbidden areasinfo:eu-repo/semantics/acceptedVersio
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