10 research outputs found

    The detailed anatomy of <i>Rhamphorhynchus</i> II: braincase, pneumatics and jaws

    No full text
    <div><p>This second contribution on <i>Rhamphorhynchus</i> based on an acid-prepared specimen provides a detailed description of the braincase, concentrating on the broken skull and its hollow bones, aiming to gather data on its pneumatisation for comparative studies between crocodiles, pterosaurs and dinosaur-birds. Computed tomographic (CT) scanning was performed to further explore these cavities in the skull bones, which are easily visible especially where the bones are broken. However, it has not been possible to observe their precise origin and connections. The skull regions where the pneumatisation is most evident are the paroccipital processes and the prootics from the endoskeletal braincase, but the precise form of the cavities is not clear, and their origin as paratympanic systems cannot be seen. CT scanning with better resolution might show more details of the skull pneumatics to be used in a phylogenetic analysis.</p></div

    A amostragem na avaliação das lixas-do-coqueiro Sampling in the evaluation of the coconut verrucoses

    No full text
    A avaliação das doenças foliares do coqueiro (Cocos nucifera L.), conhecidas como lixa-grande e lixa-pequena (verrugoses), causadas por Sphaeredothis acrocomiae e Phyllachora torrendiella, respectivamente, depara-se com o problema do método de amostragem, uma vez que não existe um método consensual em uso. Este trabalho foi realizado com o objetivo de comparar dois métodos de coleta de amostras mais utilizados na avaliação dessas doenças: método A: coleta de seis folíolos/planta, em uma única folha; método B: coleta de seis folíolos/planta, um em cada folha. O estudo foi desenvolvido a partir de três amostras de 300 folíolos (dez plantas x cinco folhas x seis folíolos), coletados em três genótipos de coqueiro, nos quais foi determinado o número de estromas da lixa-grande e da lixa-pequena. Com base nesses dados, estimaram-se as variâncias de folhas dentro de plantas e folíolos dentro de folhas e plantas, necessárias para os cálculos das estimativas das médias amostrais nos dois métodos em comparação, além de outras alternativas formuladas. Em ambas as lixas, em todos os genótipos, as estimativas da variância da média amostral calculadas pelo método A foram superiores às calculadas pelo método B, o que comprova que este último é mais eficaz que o primeiro. Outros tamanhos de amostra também foram avaliados e comparados ao método B, e constatou-se que amostras de seis folhas/planta, coletando-se, em cada uma, dois ou três folíolos, reduzem a variância amostral em 20% ou 30%, respectivamente, podendo, portanto, ser utilizadas com mais eficiência.<br>The evaluation of leaf diseases of coconuts, Cocos nucifera L., known as large verrucose and small verrucose, caused by Sphaerodothis acrocomiae and Phyllachora torrendiella, respectively, come upon the problem of sampling method. Since there is not a consensual method for measuring coconut verrucose incidence, the present work was done with the objective of comparing two sampling methods of common use: method A: sampling six leaflets/plant in a single leaf; method B: sampling six leaflets/plant, from different leaves. The study was developed starting from three samples of 300 leaflets (ten plants x five leaves x six leaflets) collected in three coconut genotypes, in which the stromata number of large verrucose and of small verrucose were counted. Throughout these data the variance was calculated from the leaf in the plant and the leaflet in the leaf and plant, necessary for the estimated sample average in the two compared methods, as well in the other formulated alternatives. For the two diseases, in all the genotypes, the estimate of variance of the sample mean calculated by the A method was higher than the one calculated by the B method, showing that the last method is more appropriate than the first one. Other sample sizes were also studied and compared by the B method, resulting that sample of two or three leaflets collected in six leaves per plant decreased sample variance on respectively 20% or 30%, probably being of more accurate applicability

    Interpreting character variation in turtles:Araripemys barretoi (Pleurodira: Pelomedusoides) from the Araripe Basin, Early Cretaceous of Northeastern Brazil

    Get PDF
    The Araripe Basin (Northeastern Brazil) has yielded a rich Cretaceous fossil fauna of both vertebrates and invertebrates found mainly in the Crato and Romualdo Formations, of Aptian and Albian ages respectively. Among the vertebrates, the turtles were found to be quite diverse, with several specimens retrieved and five valid species described to this date for the Romualdo Formation. There were also records of turtles from Ipubi and Crato Formations, mainly fragmentary material which precluded proper specific identification; however, Araripemys barretoi is supposed to occur on both Crato and Romualdo Formations. Here we describe thirteen specimens of A. barretoi-including the first description of an almost complete individual, bearing a skull, from the Crato Formation. We report a great amount of morphological variation, interpreted as being essentially of intraspecific nature, including individual, sexual and ontogenetic variation

    Plant succession in a forest on the Lower Northeast Slope of Serra Geral, Rio Grande do Sul, and Holocene palaeoenvironments, Southern Brazil

    No full text
    The study of plant succession provides information on vegetation dynamics of a region and, therefore, improves our understanding of the natural trends of present ecosystems. With this objective, plant succession based on palynology of a sediment profile in a swamp forest was studied on the Lower Northeast Slope of Serra Geral, Rio Grande do Sul. Samples were treated with HCl, HF, KOH and acetolysis; slides were mounted in glycerol-jelly. For each sample a minimum of 500 grains of pollen + pteridophyte and bryophyte spores was counted and other palynomorphs were counted in parallel. Tilia and Tilia Graph software were used to construct percentage and concentration diagrams, with three 14C datings. The results show a local water reservoir in the beginning of the Holocene (&plusmn; 9800 yrs. BP), creating a herbaceous plant marsh by hydrosere. The initial colonization of the marsh by trees occurred about 8800 yrs. BP, with tropical species from the Coastal Plain migrating in an east-west direction. Afterwards, there was a dry phase between 7000-5000 yrs. BP. The second appearance of regional tree species began at about 5000 yrs. BP, resulting in the present forest and in the west-east migration of tropical species from interior lowlands, like this one, to re-colonize the coast after the last marine regression

    Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

    No full text
    International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora

    Association between administration of IL-6 antagonists and mortality among patients hospitalized for COVID-19 : a meta-analysis

    No full text
    IMPORTANCE Clinical trials assessing the efficacy of IL-6 antagonists in patients hospitalized for COVID-19 have variously reported benefit, no effect, and harm. OBJECTIVE To estimate the association between administration of IL-6 antagonists compared with usual care or placebo and 28-day all-cause mortality and other outcomes. DATA SOURCES Trials were identified through systematic searches of electronic databases between October 2020 and January 2021. Searches were not restricted by trial status or language. Additional trials were identified through contact with experts. STUDY SELECTION Eligible trials randomly assigned patients hospitalized for COVID-19 to a group in whom IL-6 antagonists were administered and to a group in whom neither IL-6 antagonists nor any other immunomodulators except corticosteroids were administered. Among 72 potentially eligible trials, 27 (37.5%) met study selection criteria. DATA EXTRACTION AND SYNTHESIS In this prospectivemeta-analysis, risk of biaswas assessed using the Cochrane Risk of Bias Assessment Tool. Inconsistency among trial results was assessed using the I-2 statistic. The primary analysis was an inverse variance-weighted fixed-effects meta-analysis of odds ratios (ORs) for 28-day all-cause mortality. MAIN OUTCOMES AND MEASURES The primary outcome measurewas all-cause mortality at 28 days after randomization. There were 9 secondary outcomes including progression to invasive mechanical ventilation or death and risk of secondary infection by 28 days. RESULTS A total of 10 930 patients (median age, 61 years [range of medians, 52-68 years]; 3560 [33%] were women) participating in 27 trials were included. By 28 days, there were 1407 deaths among 6449 patients randomized to IL-6 antagonists and 1158 deaths among 4481 patients randomized to usual care or placebo (summary OR, 0.86 [95% CI, 0.79-0.95]; P =.003 based on a fixed-effects meta-analysis). This corresponds to an absolute mortality risk of 22% for IL-6 antagonists compared with an assumed mortality risk of 25% for usual care or placebo. The corresponding summary ORs were 0.83 (95% CI, 0.74-0.92; P <.001) for tocilizumab and 1.08 (95% CI, 0.86-1.36; P =.52) for sarilumab. The summary ORs for the association with mortality compared with usual care or placebo in those receiving corticosteroids were 0.77 (95% CI, 0.68-0.87) for tocilizumab and 0.92 (95% CI, 0.61-1.38) for sarilumab. The ORs for the association with progression to invasive mechanical ventilation or death, compared with usual care or placebo, were 0.77 (95% CI, 0.70-0.85) for all IL-6 antagonists, 0.74 (95% CI, 0.66-0.82) for tocilizumab, and 1.00 (95% CI, 0.74-1.34) for sarilumab. Secondary infections by 28 days occurred in 21.9% of patients treated with IL-6 antagonists vs 17.6% of patients treated with usual care or placebo (OR accounting for trial sample sizes, 0.99; 95% CI, 0.85-1.16). CONCLUSIONS AND RELEVANCE In this prospectivemeta-analysis of clinical trials of patients hospitalized for COVID-19, administration of IL-6 antagonists, compared with usual care or placebo, was associated with lower 28-day all-cause mortality
    corecore