Palinofácies e análise organogeoquímica da formação Morro do Chaves, Bacia Sergipe-Alagoas, Brasil

A Formação Morro do Chaves (Barremiano-Aptiano), correspondente à seção rifte da Bacia Sergipe-Alagoas, vem sendo amplamente estudada por ser considerada análoga aos reservatórios do intervalo Pré-Sal das Bacias de Santos e Campos. É constituída por coquinas com intercalações de folhelhos e arenitos depositados em ambiente lacustre durante o rifteamento que resultou na abertura do Oceano Atlântico. Foram utilizadas 48 amostras coletadas do testemunho 2-SMC-3-AL, retirado da Pedreira Atol em São Miguel dos Campos (AL). Este trabalho propõem o estudo da assembleia de constituintes orgânicos desta sucessão sedimentar, através da análise palinofaciológica e análise organogeoquímica, com a finalidade de colaborar com a compreensão da evolução paleoambiental durante o Aptiano. A palinofácies possibilita a identificação e classificação dos grupos e subgrupos da matéria orgânica particulada, através de técnicas de microscopia utilizando luz branca transmitida e luz azul incidente (fluorescência). Já a análise organogeoquímica permite a quantificação do teor de Carbono Orgânico Total (COT), Enxofre Total (ST) e Resíduo Insolúvel (RI) presente nos sedimentos. Dentre as quarenta e oito amostras submetidas à acidificação com ácido clorídrico e fluorídrico, apenas oito apresentaram boa recuperação da matéria orgânica. Estas amostras apresentaram COT variando de 0,12 a 13,45%, teor de ST variando de 0,81 a 2,51% indicando períodos mais redutores e valores percentuais altos de RI caracterizando litologias predominantemente siliciclásticas. O grupo Amorfo (MOA bacteriana, fitoplanctônica de água doce e vegetal) apresenta predominância nestas amostras. Há também a ocorrência de Botryococcus e esporomorfos, correspondentes ao grupo Palinomorfo, assim como ocorrência de zooclastos. A correlação de todos os dados sugere um paleoambiente lacustre com variações de regimes óxicos a disóxicos-anóxicos, associados a um clima árido e com vegetação ao seu entorno

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Parada cardiorrespiratória em raquianestesia

JUSTIFICATIVA E OBJETIVOS: A raquianestesia faz parte do dia a dia de inúmeros anestesiologistas. É considerada bastante segura, embora existam algumas complicações relacionadas a essa técnica, dentre as quais a mais temida é a ocorrência de parada cardiorrespiratória (PCR). A incidência real de PCR relacionada à raquianestesia, bem como sua etiologia, ainda não estão completamente elucidadas, o que motivou a realização deste artigo. CONTEÚDO: Foram revisados artigos publicados, nos últimos vinte anos, em revistas indexadas ao Medline e em um livro-texto. O propósito desta revisão foi identificar a incidência de PCR relacionada à anestesia subaracnoidea e a etiologia desses casos. Procurou-se também identificar eventuais fatores de risco. Por fim, as estratégias de tratamento descritas na literatura foram revisadas a fim de se determinar a melhor conduta diante de um caso de PCR no curso de bloqueio espinhal. CONCLUSÕES: A incidência de PCR relacionada à raquianestesia é bastante variável, e parece ser menor quando comparada à anestesia geral. No passado, acreditava-se que a PCR era decorrente de hipoxemia, relacionada, principalmente, à sedação excessiva. Entretanto, hoje se sabe que a PCR no curso de um bloqueio subaracnoideo tem etiologia cardiocirculatória, relacionada principalmente à redução da pré-carga resultante do bloqueio simpático. Existem também outros fatores que aumentam o risco para o desenvolvimento de PCR, dentre os quais merecem relevância: alterações no posicionamento do paciente e hipovolemia. Em relação ao tratamento, está bem sedimentado que o mais importante é que seja instituído precocemente. Além de um agente vagolítico, deve-se lançar mão precocemente de um simpaticomimético, em especial adrenalina, a fim de minimizar os danos para o paciente

Biological invasions in brazilian environmental science courses: do we need new approaches?

The increasing destruction of natural environments worldwide favored more and more alien species’ dispersal, distancing people from nature and consequently from native species. We investigated undergrad students’ perception about alien and native Brazilian species evaluating classes of the first (freshmen) and last semesters (seniors) of four courses in environmental sciences in three institutions and assessed these students’ knowledge level in different aspects related to native and alien species. The 509 interviewees were able to identify Brazilian native species better than alien species. They also produced better identifications among taxonomic groups of mammals (either alien or native), native birds, and exotic fish compared to invertebrate species. Most students did not consider themselves well informed about the topic. We found an association between the courses/semesters attended and the level of knowledge of the students. Thus, we concluded that, on the one hand, the students demonstrated relevant knowledge about the native species but, on the other, presented deficiencies in invasive alien species’ knowledge. Therefore, we suggest the revision/restructuring of how the biological invasions theme is covered in the academic curricula of undergraduate courses in the environmental area