Relative humidity predominantly determines long‐term biocrust‐forming lichen cover in drylands under climate change

1. Manipulative experiments typically show a decrease in dryland biocrust cover and altered species composition under climate change. Biocrust‐forming lichens, such as the globally distributed Diploschistes diacapsis, are particularly affected and show a decrease in cover with simulated climate change. However, the underlying mechanisms are not fully understood, and long‐term interacting effects of different drivers are largely unknown due to the short‐term nature of the experimental studies conducted so far. 2. We addressed this gap and successfully parameterised a process‐based model for D. diacapsis to quantify how changing atmospheric CO2, temperature, rainfall amount and relative humidity affect its photosynthetic activity and cover. We also mimicked a long‐term manipulative climate change experiment to understand the mechanisms underlying observed patterns in the field. 3. The model reproduced observed experimental findings: warming reduced lichen cover, whereas less rainfall had no effect on lichen performance. This warming effect was caused by the associated decrease in relative humidity and non‐rainfall water inputs, which are major water sources for biocrust‐forming lichens. Warming alone, however, increased cover because higher temperatures promoted photosynthesis during early morning hours with high lichen activity. When combined, climate variables showed non‐additive effects on lichen cover, and effects of increased CO2 levelled off with decreasing levels of relative humidity. 4. Synthesis. Our results show that a decrease in relative humidity, rather than an increase in temperature, may be the key factor for the survival of the lichen D. diacapsis under climate change and that effects of increased CO2 levels might be offset by a reduction in non‐rainfall water inputs in the future. Because of a global trend towards warmer and drier air and the widespread global distribution of D. diacapsis, this will affect lichen‐dominated dryland biocrust communities and their role in regulating ecosystem functions worldwide.This research was supported by the Collaborative Research Centre 973 (www.sfb973.de) of the German Research Foundation (DFG) and by the European Research Council (grant agreement no. 647038 (BIODESERT)). P. Porada appreciates funding by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—408092731. F.T. Maestre acknowledges support from Generalitat Valenciana (CIDEGENT/2018/041) and the Alexander Von Humboldt Foundation. J. Raggio acknowledges the ERA-Net BiodivERsA program as Soil Crust InterNational (SCIN) and The Spanish Ministerio de Economía y Competitividad (MINECO) project numbers PRI-PIMBDV-2011-0874 and CRYPTOCOVER, CTM2015-64728-C21-R

Himantormia lugubris, an Antarctic endemic on the edge of the lichen symbiosis

Himantormia lugubris is an Antarctic endemic with a distribution restricted to the northwest tip of Antarctic Peninsula, adjacent islands and South Georgia Island. In this region H. lugubris is an important component of the epilithic lichen community. The species has a fruticose thallus with usually simple and flattened branches whose grey surface is often disrupted exposing the black and dominant chondroid axis. Because the photobiont cells are mainly restricted to the patchy grey areas, positive carbon balance seems to be rather difficult for this species. Therefore, the aim of this paper is to elucidate which functional strategy, possibly linked with thallus anatomy, is used by H. lugubris that enables it to be a successful species in the maritime Antarctic. To achieve this goal, we constructed a picture of the lichen’s physiological, anatomical and morphological characteristics by using a broad range of technologies, such as chlorophyll fluorescence, CO exchange and electron microscopy. We found that H. lugubris has a very low net photosynthesis, apparently restricted to the grey areas, but high respiratory rates. Therefore, positive net photosynthesis is only possible at low temperatures. Chlorophyll content is also low but is present in both gray and black areas. Our conclusion is that the only possibility for this species to achieve a positive carbon balance is to be active for long periods under optimal conditions, that means, wet, cold and with enough light, a common combination in this region of Antarctica. Given these constrains, we suggest that H. lugubris is likely to be especially sensitive species to predicted climate warming in the maritime Antarctic.Field work as well as most of the lab experiments were supported by the grant CTM2015-64728-C2-1-R (MINECO/FEDER, UE). Electron microscopy work wassupported by the grant CTM2015-64728-C2-2-R (MINECO/FEDER, UE)

Exploring environmental and physiological drivers of the annual carbon budget of biocrusts from various climatic zones with a mechanistic data-driven model

Biocrusts are a worldwide phenomenon, contributing substantially to ecosystem functioning. Their growth and survival depend on multiple environmental factors, including climatic ones, and the relations of these factors to physiological processes. Responses of biocrusts to individual environmental factors have been examined in a large number of field and laboratory experiments. These observational data, however, have rarely been assembled into a comprehensive, consistent framework that allows quantitative exploration of the roles of multiple environmental factors and physiological properties for the performance of biocrusts, in particular across climatic regions. Here we used a data-driven mechanistic modelling framework to simulate the carbon balance of biocrusts, a key measure of their growth and survival. We thereby assessed the relative importance of physiological and environmental factors for the carbon balance at six study sites that differ in climatic conditions. Moreover, we examined the role of seasonal acclimation of physiological properties using our framework, since the effects of this process on the carbon balance of biocrusts are poorly constrained so far. We found substantial effects of air temperature, CO2 concentration, and physiological parameters that are related to respiration on biocrust carbon balance, which differ, however, in their patterns across regions. The ambient CO2 concentration is the most important factor for biocrusts from drylands, while air temperature has the strongest impact at alpine and temperate sites. Metabolic respiration cost plays a more important role than optimum temperature for gross photosynthesis at the alpine site; this is not the case, however, in drylands and temperate regions. Moreover, we estimated a small annual carbon gain of 1.5 g m−2 yr−1 by lichen-dominated biocrust and 1.9 g m−2 yr−1 by moss-dominated biocrust at a dryland site, while the biocrusts lost a large amount of carbon at some of the temperate sites (e.g. −92.1 for lichen-dominated and −74.7 g m−2 yr−1 for moss-dominated biocrust). These strongly negative values contradict the observed survival of the organisms at the sites and may be caused by the uncertainty in environmental conditions and physiological parameters, which we assessed in a sensitivity analysis. Another potential explanation for this result may be the lack of acclimation in the modelling approach, since the carbon balance can increase substantially when testing for seasonally varying parameters in the sensitivity analysis. We conclude that the uncertainties in air temperature, CO2 concentration, respiration-related physiological parameters, and the absence of seasonal acclimation in the model for humid temperate and alpine regions may be a relevant source of error and should be taken into account in future approaches that aim at estimating the long-term biocrust carbon balance based on ecophysiological data.</p

Efeito da concentração de clorexidina na resistência de união à dentina em dentes decíduos

PURPOSE: To evaluate the effect of the use of 0.5% and 2% chlorhexidine digluconate on the immediate bond strength of a conventional adhesive system to dentin in primary teeth. METHODS: Twenty-one healthy primary molars were divided into three groups (n=7), being one control (A) and two experimental groups (B and C). After dentin exposure, in Group (A) the adhesive procedure was performed using 37% phosphoric acid gel (15 s); dentin was washed (15 s), air dried (30 s) and rehydrated with water. Groups B and C followed similar procedures but for re-hydration with 0.5% and 2% chlorhexidine, respectively, for 30 s. A resin composite block was built simulating a restoration, and the teeth were stored in distilled water at 37°C for 24 h before the microtensile bond strength test. The bond strength data were analyzed by analysis of variance. RESULTS: No statistically significant difference in bond strength was found among the tested groups (P>0.05) CONCLUSION: The 0.5% and 2% concentrations of chlorhexidine presented similar behavior and caused no adverse effects on the bond strength to dentin in primary teeth.OBJETIVO: Avaliar o efeito do uso de digluconato de clorexidina 0,5% e 2% na resistência de união imediata à dentina de dentes decíduos para um sistema adesivo convencional. METODOLOGIA: Vinte e um molares decíduos hígidos foram divididos em três grupos (n=7), sendo um controle e dois experimentais. Após a exposição da dentina, foi realizado no grupo controle (A) o procedimento adesivo utilizando ácido fosfórico gel a 37% (15 s); a superfície foi então lavada (15 s), seca com ar (30 s) e reidratada com água. Os grupos B e C foram idênticos ao grupo A, apenas com diferença no reumidecimento de clorexidina 0,5% e 2% respectivamente, por 30 s. Após a confecção do bloco de resina composta, os dentes foram armazenados em água destilada a 37°C por 24 h antes do teste de microtração. Os dados de resistência de união foram avaliados através de análise de variância. RESULTADOS: Os dados apresentaram distribuição homogênea, não havendo diferença estatisticamente significante entre os grupos (P>0,05). CONCLUSÃO: As concentrações de clorexidina a 0,5% e 2% apresentaram comportamentos similares e não causaram efeitos adversos na resistência de união em dentina de dentes decíduos, quando comparadas ao grupo controle

Impact of Subsyndromal Delirium Occurrence and Its Trajectory during ICU Stay

Funding Information: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Publisher Copyright: © 2022 by the authors.Despite recent advances in the field, the association between subsyndromal delirium (SSD) in the ICU and poor outcomes is not entirely clear. We performed a retrospective multicentric observational study analyzing mental status during the first 72 h of ICU stay. Of the 681 patients included, SSD occurred in 22.7%. Considering the worst cognitive assessment during the first 72 h, 233 (34%) patients had normal mental status, 124 (18%) patients had SSD and 324 (48%) patients had delirium or coma. SSD was not independently associated with an increased risk of death when compared with normal mental status (OR 95%IC 1.0 vs. 1.35 [0.73–1.49], p = 0.340), but was associated with a longer ICU LOS (7.0 (4–12) vs. 4 (3–8) days, p 23 points. Our findings support the association of SSD with increased ICU LOS, but not with ICU mortality. Monitoring the trajectory of SSD early at ICU admission can help to identify patients with increased risk of conversion from SSD to delirium or coma.publishersversionpublishe

Mortalidade hospitalar por covid-19 em crianças e adolescentes no Brasil em 2020–2021

OBJECTIVE: To describe cases, deaths, and hospital mortality from covid-19 in children andadolescents in Brazil, according to age group, during the evolving phases of the pandemic in2020 and 2021.METHODS: Census of patients aged up to 19 committed with severe acute respiratory syndrome, due to covid-19 or unspecified, notified to the Brazilian Influenza Epidemiological Surveillance Information System, from January 1, 2020, to December 31, 2021. The two years were divided into six phases, covering the spread of the disease—first, second and third wave—as well as the impact of vaccination. The pediatric population was categorized into infants, preschoolers, schoolchildren, and adolescents. Hospital mortality was assessed by pandemic phase and age group.RESULTS: A total of 144,041 patients were recorded in the two years, 18.2% of whom had confirmed cases of covid-19. Children under 5 years old (infants and preschoolers) accounted for 62.8% of those hospitalized. A total of 4,471 patients died, representing about 6.1 deaths per day. Infants were the ones who most progressed to the intensive care unit (24.7%) and had the highest gross number of deaths (n = 2,012), but mortality was higher among adolescents (5.7%), reaching 9.8% in phase 1. The first peak of deaths occurred in phase 1 (May/2020), and two other peaks occurred in phase 4 (March/2021 and May/2021). There was an increase in cases and deaths for younger ages since phase 4. Hospital mortality in the pediatric population washigher in phases 1, 4, and 6, following the phenomena of dissemination/interiorization of thevirus in the country, beginning of the second wave and beginning of the third wave, respectively.CONCLUSION: The absolute number of cases o f covid-19 in children and adolescents is significant. Although complete vaccination in descending order of age provided a natural deviation in age range, there was a greater gap between the curve of new hospitalized cases and the curve of deaths, indicating the positive impact of immunization.OBJETIVO: Descrever casos, óbitos e mortalidade hospitalar por covid-19 em crianças e adolescentes no Brasil, conforme faixa etária, durante as fases de evolução da pandemia em 2020 e 2021. MÉTODOS: Censo de pacientes de até 19 anos internados com síndrome respiratória aguda grave, por covid-19 ou não especificada, notificados ao Sistema de Informação de Vigilância Epidemiológica da Gripe do Brasil, entre 1 de janeiro de 2020 e 31 de dezembro de 2021. Os dois anos foram divididos em seis fases, abrangendo a disseminação da doença − primeira, segunda e terceira onda −, bem como o impacto da vacinação. A população pediátrica foi categorizada em lactentes, pré-escolares, escolares e adolescentes. A mortalidade hospitalar foi avaliada por fase da pandemia e faixa etária. RESULTADOS: Foram contabilizados 144.041 pacientes nos dois anos, sendo 18,2% casos de covid-19 confirmados. Menores de 5 anos (lactentes e pré-escolares) corresponderam a 62,8% dos hospitalizados. Evoluíram a óbito 4.471, representando cerca 6,1 óbitos por dia. Os lactentes foram os que mais evoluíram para unidade de terapia intensiva (24,7%) e apresentaram o maior número bruto de óbito (n = 2.012), porém a mortalidade foi maior entre os adolescentes (5,7%), chegando a 9,8% na fase 1. O primeiro pico de óbitos ocorreu na fase 1 (maio/2020), e outros dois picos ocorreram na fase 4 (março/2021 e maio/2021). Verificou-se avanço de casos e óbitos para as idades inferiores desde a fase 4. A mortalidade hospitalar na população pediátrica foi maior nas fases 1, 4 e 6, acompanhando os fenômenos de disseminação/interiorização do vírus no país, início da segunda onda e início da terceira onda, respectivamente. CONCLUSÃO: O número absoluto de casos de covid-19 em crianças e adolescentes é expressivo. Embora a vacinação completa em ordem decrescente de idade tenha proporcionado um desvio natural de faixa etária, ocorreu um distanciamento maior entre a curva de novos casos hospitalizados e a curva de óbitos, indicando o impacto positivo da imunização

Conservative treatment of deep dentin lesions in primary molars: Case-series

Objective: To carry out a descriptive analysis of a case-series in which the indirect pulp capping (IPC) has been performed for treating primary molars with extensive caries lesions in dentin, in the Private of Specialization in Pediatric Dentistry. Material and Methods: A single calibrated examiner evaluated the medical records of 155 patients aged 2 to 13 years attended at the Foundation for Scientific and Technological Development of Dentistry (FUNDECTO) partnership the University of São Paulo (USP) in 2011-2013 in search of extensive caries lesions treated during this period. Were found only 20 deep caries lesions and with satisfactory clinical and radiographic documentation. Then, the materials and techniques used were collected, as well as instant success described after treatment and observation for no progression of the disease (pain, abscess or fistula). Results: The 20 lesions evaluated reached at least 2/3 of the dentin thickness and were active. In 70% of cases, the restorations were carried out with high viscosity or encapsulated glass ionomer cement, and in 30% of case with light-cured resin. In only one case was used calcium hydroxide cement as liner material before inserting resin. In the teeth treated, only three cases were considered failures. Conclusion: Regardless of the restorative material used and the technique employed, good immediate success rates of the conservative treatment in deep dentin lesions were found, which consequently reduces the risk of exposure and pulp intervention