Does the degradation of histosols due to recurrent fire affect the establishment of a hygrophilal autochthonous tree species?

Forest Islands and their adjacent natural grasslands are vulnerable and sensitive ecosystems to the actions of severe fires, which result in losses of their resilience, which makes the potential of passive restoration of these environments unfeasible after such events. This study aims to verify, through an autochthonous species exclusive to these Forest Islands, whether it can develop in Histosols around a Forest Island that has been degraded by fire for years. The place of study and collection of the material tested was in the Sempre-Vivas National Park. Histosols samples were collected for analysis of chemical and physical attributes and experimental conduction in a seedling nursery. The performance of Richeria grandis was evaluated in these Histosols from seed vigor tests, initial plant growth in a greenhouse. R. grandis manages to develop in Histosols around the degraded Forest Island, disregarding possible interspecific field competitions. The physical and chemical characteristics of the Histosols around the island do not prevent the effective restoration of this phytocenosis. R. grandis showed the same seed vigor for all Histosols tested and all seedlings survived until the end of the experiment. It was observed that the seedlings grown in the Histosols of the island of the forest, showed a behavior of greater height, number of leaves and moisture content, and the place with exposed Histosols, with the highest fire severity, provided the lowest development in height, diameter and number of leaves. According to ecophysiological analyses, the species is under some environmental stress regardless of the treatment.

Pooling of sputum samples to increase tuberculosis diagnostic capacity in Brazil during the COVID-19 pandemic.

OBJECTIVES: We assessed whether combining (pooling) four individual's samples and testing with Xpert Ultra has the same accuracy as testing samples individually as a more efficient testing method. METHODS: We conducted a cross-sectional study of individuals with presumptive tuberculosis attending primary health care or general hospital facilities in Alagoas, Brazil. The sputum samples of four consecutive individuals were pooled and the pool and individual samples were tested with Xpert Ultra. The agreement of the tests was compared using kappa statistics. We estimated the sensitivity and specificity of pooling using the individual test as the reference standard and potential cartridge savings. RESULTS: A total of 396 participants were tested. A total of 95 (24.0%) individual samples were Mycobacterium tuberculosis (MTB)-positive, 300 (75.8%) "MTB not detected", including 20 "MTB trace", and one reported an error. A total of 99 pools of four samples were tested, of which 62 (62.6%) had MTB detected and 37 (37.4%) MTB not detected, including six (6.1%) with MTB trace. The agreement between individual and pooled testing was 96.0%. Pooling had a sensitivity of 95.0% (95% confidence interval 86.9-99%), specificity of 97.1% (95% confidence interval 85.1-99.9%), and kappa of 0.913. The method saved 12.4% of cartridge costs. CONCLUSION: The pooled testing of specimens had a high level of agreement with individual testing. The pooling of samples for testing improves the efficiency of testing, potentially enabling the screening and testing of larger numbers of individuals more cost-effectively.

Germinação in vitro e aclimatação de plântulas de sucupira-preta (Bowdichiavirgilioides Kunth. ) / In vitro germination and acclimation of sucupira-preta seedlings(Bowdichiavirgilioides Kunth. )

Este trabalho teve como objetivos avaliar a germinação in vitro e a aclimatação de plantas de sucupira-preta (Bowdichia virgilioides). Sementes escarificadas e não escarificadas foram inoculadas em tubos de ensaio contendo meio de cultura MS ou WPM, com 100 ou 50% dos sais e vitaminas; suplementados com dois tipos de aditivos, carvão ativado e PVP, e mantidas em sala de cultura. Utilizou-se um delineamento inteiramente casualisado em esquema fatorial 2x4 (dois aditivos e quatro formulações de meio de cultura) com quatro repetições e seis sementes por repetição. Aos 30 dias obteve-se o percentual de germinação e o índice de velocidade de germinação (IVG). As plantas foram transferidas para tubetes, contendo substrato e aclimatadas em casa de vegetação, onde permaneceram durante 60 dias, sendo transferidas para casa de sombra, onde permaneceram por mais 60 dias. Aos 30, 60, 90 e 120 dias avaliaram-se o percentual de sobrevivência e a altura das mudas aclimatadas. A germinação in vitro de sementes escarificadas apresenta os maiores percentuais utilizando-se os meios de cultura MS e WPM reduzidos à metade da concentração dos sais e vitaminas. A germinação ocorre independentemente do aditivo utilizado tanto para sementes escarificadas como para as não escarificadas. A aclimatação das plantas germinadas in vitro ocorre independentemente do histórico de aditivos ou meios de cultura utilizados.

Thiss tudy objectived to evaluate the in vitro germination and acclimatization of plants sucupirapreta (Bowdichia virgilioides). Scarified and not scarified seeds were inoculated in test tubes containing culture medium MSorWPM, 100 or 50% of salts and vitamins, supplemented with two types of additives, activated charcoal and PVP, and kept in culture room. We used acompletely randomized in a 2x4 factorial design (2additives and 4culture medium formulations) with 4 replications and6 seeds per replicate. At 30 days gave the germination percentage and germination speed index(IVG). Plants were transferred to tubes containing substrate and acclimatized in a greenhouse, where they remained for 60days and transferred to a dusk house, where they remained for another 60days.At 30, 60, 90 and 120 days, we assessed the percentage of survival and seedling height acclimated. The in vitro germination of scarified seeds had the highest percentage using culture media MS and WPM halved the concentration of salts and vitamins. Germination occurred regardless of additive used both to scarified and note scarified seeds. The acclimation of plants germinated in vitro occurred regardless of additives history or culture media used.