Shifts in plant functional groups along an aridity gradient in a tropical dry forest.

Increasing aridity associated with climate change may lead to the crossing of critical ecosystem thresholds in drylands, compromising ecosystem services for millions of people. In this context, finding tools to detect at early stages the effects of increasing aridity on ecosystems is extremely urgent to avoid irreversible damage. Here, we assess shifts in plant community functional structure along a spatial aridity gradient in tropical dryland (Brazilian Caatinga), to select the most appropriate plant functional groups as ecological indicators likely useful to predict temporal ecosystem trajectories in response to aridity. We identified seven plant functional groups based on 13 functional traits associated with plant establishment, defense, regeneration, and dispersal, whose relative abundances changed, linearly and non-linearly, with increasing aridity, showing either increasing or decreasing trends. Of particular importance is the increase in abundance of plants with high chemical defense and Crassulacean Acid Metabolism (CAM) photosynthetic pathway, with increasing aridity. We propose the use of these functional groups as early warning indicators to detect aridity impacts on these dryland ecosystems and shifts in ecosystem functioning. This information can also be used in the elaboration of mitigation and ecological restoration measures to prevent and revert current and future climate change impacts on tropical dry forests.

Understanding plant responses to saline waterlogging: insights from halophytes and implications for crop tolerance.

MAIN CONCLUSION: Saline and wet environments stress most plants, reducing growth and yield. Halophytes adapt with ion regulation, energy maintenance, and antioxidants. Understanding these mechanisms aids in breeding resilient crops for climate change. Waterlogging and salinity are two abiotic stresses that have a major negative impact on crop growth and yield. These conditions cause osmotic, ionic, and oxidative stress, as well as energy deprivation, thus impairing plant growth and development. Although few crop species can tolerate the combination of salinity and waterlogging, halophytes are plant species that exhibit high tolerance to these conditions due to their morphological, anatomical, and metabolic adaptations. In this review, we discuss the main mechanisms employed by plants exposed to saline waterlogging, intending to understand the mechanistic basis of their ion homeostasis. We summarize the knowledge of transporters and channels involved in ion accumulation and exclusion, and how they are modulated to prevent cytosolic toxicity. In addition, we discuss how reactive oxygen species production and cell signaling enhance ion transport and aerenchyma formation, and how plants exposed to saline waterlogging can control oxidative stress. We also address the morphological and anatomical modifications that plants undergo in response to combined stress, including aerenchyma formation, root porosity, and other traits that help to mitigate stress. Furthermore, we discuss the peculiarities of halophyte plants and their features that can be leveraged to improve crop yields in areas prone to saline waterlogging. This review provides valuable insights into the mechanisms of plant adaptation to saline waterlogging thus paving the path for future research on crop breeding and management strategies.

Prognostic value of Doppler waveform analysis of common femoral vein in septic patients: a prospective cohort study.

OBJECTIVES: To assess whether there is an association between abnormal common femoral vein (CFV) Doppler waveform and intensive care unit (ICU) mortality in patients with sepsis. METHODS: Patients admitted to the ICU with sepsis were included. Pulsed-wave Doppler was performed by examining the CFV in the short axis without angle correction and in the long axis with angle correction. An abnormal CFV Doppler waveform was determined by a retrograde velocity peak (RVP) > 10 cm/s in the long axis or RVP > 50% of the antegrade velocity peak in the short axis. TAPSE < 17 mm was defined as right ventricular (RV) dysfunction. The primary outcome was ICU mortality. RESULTS: One hundred and ten patients were included. There was no association between abnormal CFV Doppler waveforms in the long (p = 0.709) and short axes (p = 0.171) and ICU mortality. TAPSE measurements were performed in 16 patients. RV dysfunction was identified in 8 (50.0%) patients. There was no association between the diagnosis of RV dysfunction based on TAPSE measurement and the identification of abnormal CFV Doppler waveforms in the long axis (p = 1.000) and in the short axis (p = 1.000). CONCLUSION: Abnormal CFV Doppler waveforms were not associated with ICU mortality in patients with sepsis. Furthermore, in the exploratory analysis, these alterations were not useful in identifying RV dysfunction in these patients.

The metabolic interplay between dietary carbohydrate and exercise and its role in acute appetite regulation in males: a randomized controlled study.

An understanding of the metabolic determinants of postexercise appetite regulation would facilitate development of adjunctive therapeutics to suppress compensatory eating behaviours and improve the efficacy of exercise as a weight-loss treatment. Metabolic responses to acute exercise are, however, dependent on pre-exercise nutritional practices, including carbohydrate intake. We therefore aimed to determine the interactive effects of dietary carbohydrate and exercise on plasma hormonal and metabolite responses and explore mediators of exercise-induced changes in appetite regulation across nutritional states. In this randomized crossover study, participants completed four 120 min visits: (i) control (water) followed by rest; (ii) control followed by exercise (30 min at ∼75% of maximal oxygen uptake); (iii) carbohydrate (75 g maltodextrin) followed by rest; and (iv) carbohydrate followed by exercise. An ad libitum meal was provided at the end of each 120 min visit, with blood sample collection and appetite assessment performed at predefined intervals. We found that dietary carbohydrate and exercise exerted independent effects on the hormones glucagon-like peptide 1 (carbohydrate, 16.8 pmol/L; exercise, 7.4 pmol/L), ghrelin (carbohydrate, -48.8 pmol/L; exercise: -22.7 pmol/L) and glucagon (carbohydrate, 9.8 ng/L; exercise, 8.2 ng/L) that were linked to the generation of distinct plasma 1 H nuclear magnetic resonance metabolic phenotypes. These metabolic responses were associated with changes in appetite and energy intake, and plasma acetate and succinate were subsequently identified as potential novel mediators of exercise-induced appetite and energy intake responses. In summary, dietary carbohydrate and exercise independently influence gastrointestinal hormones associated with appetite regulation. Future work is warranted to probe the mechanistic importance of plasma acetate and succinate in postexercise appetite regulation. KEY POINTS: Carbohydrate and exercise independently influence key appetite-regulating hormones. Temporal changes in postexercise appetite are linked to acetate, lactate and peptide YY. Postexercise energy intake is associated with glucagon-like peptide 1 and succinate levels.

Nitrate supply decreases fermentation and alleviates oxidative and ionic stress in nitrogen-fixing soybean exposed to saline waterlogging.

Nitrate (NO3 - ) nutrition is known to mitigate the damages caused by individual stresses of waterlogging and salinity. Here, we investigated the role of NO3 - in soybean plants exposed to these stresses in combination. Nodulated soybean cultivated under greenhouse conditions and daily fertilised with a nutrient solution without nitrogen were subjected to the following treatments: Water, NO3 - , NaCl, and NaCl+NO3 - . Then, plants were exposed to waterlogging (6days) and drainage (2days). Compared to plants exposed to isolated stress, the saline waterlogging resulted in higher concentrations of H2 O2 , O2 ˙- , and lipid peroxidation at the whole-plant level, mainly during drainage. Furthermore, saline waterlogging increased fermentation and the concentrations of Na+ and K+ in roots and leaves both during waterlogging and drainage. NO3 - supplementation led to augments in NO3 - and NO levels, and stimulated nitrate reductase activity in both organs. In addition, NO3 - nutrition alleviated oxidative stress and fermentation besides increasing the K+ /Na+ ratio in plants exposed to saline waterlogging. In conclusion, NO3 - supplementation is a useful strategy to help soybean plants overcome saline waterlogging stress. These findings are of high relevance for agriculture as soybean is an important commodity and has been cultivated in areas prone to saline waterlogging.

How Do Taxonomic and Functional Diversity Metrics Change Along an Aridity Gradient in a Tropical Dry Forest?

Ecological indicators based on biodiversity metrics are valuable and cost-effective tools to quantify, track and understand the effects of climate change on ecosystems. Studying changes in these indicators along climatic gradients in space is a common approach to infer about potential impacts of climate change over time, overcoming the limitations of lack of sufficiently long time-series data. Here, we studied the response of complementary biodiversity metrics in plants: taxonomic diversity (species richness and Simpson index) and functional diversity (diversity and redundancy) in 113 sampling sites along a spatial aridity gradient (from 0.27 to 0.69 of aridity index-AI) of 700 km in a Tropical dry forest. We found different responses of taxonomic and functional diversity metrics to aridity. Species diversity showed a hump-shaped curve peaking at intermediate levels of aridity between 0.38 and 0.52 AI as an ecotone, probably because it is where most species, from both drier and more mesic environments, still find conditions to co-exist. Functional diversity showed a positive linear relation with increasing aridity, suggesting higher aridity favors drought-adapted species with diverse functional traits. In contrast, redundancy showed a negative linear relation with increasing aridity, indicating that drier sites have few species sharing the same functional traits and resource acquisition strategies. Thus, despite the increase in functional diversity toward drier sites, these communities are less resilient since they are composed of a small number of plant species with unique functions, increasing the chances that the loss of one of such "key species" could lead to the loss of key ecosystem functions. These findings show that the integration of complementary taxonomic and functional diversity metrics, beyond the individual response of each one, is essential for reliably tracking the impacts of climate change on ecosystems. This work also provides support to the use of these biodiversity metrics as ecological indicators of the potential impact of climate change on drylands over time.

Waterlogging priming alleviates the oxidative damage, carbohydrate consumption, and yield loss in soybean (Glycine max) plants exposed to waterlogging.

In this study, we tested whether waterlogging priming at the vegetative stage would mitigate a subsequent waterlogging event at the reproductive stage in soybean [Glycine max (L.) Merr.]. Plants (V3 stage) were subjected to priming for 7days and then exposed to waterlogging stress for 5days (R2 stage) with non-primed plants. Roots and leaves were sampled on the fifth day of waterlogging and the second and fifth days of reoxygenation. Overall, priming decreased the H2 O2 concentration and lipid peroxidation in roots and leaves during waterlogging and reoxygenation. Priming also decreased the activity of antioxidative enzymes in roots and leaves and increased the foliar concentration of phenols and photosynthetic pigments. Additionally, priming decreased fermentation and alanine aminotransferase activity during waterlogging and reoxygenation. Finally, priming increased the concentration of amino acids, sucrose, and total soluble sugars in roots and leaves during waterlogging and reoxygenation. Thus, primed plants were higher and more productive than non-primed plants. Our study shows that priming alleviates oxidative stress, fermentation, and carbohydrate consumption in parallel to increase the yield of soybean plants exposed to waterlogging and reoxygenation.

Incidence of venous thromboembolism among patients with severe COVID-19 requiring mechanical ventilation compared to other causes of respiratory failure: a prospective cohort study.

Previous studies have suggested that COVID-19 pneumonia is associated with an increased risk of venous thromboembolism (VTE). This study aimed to investigate the incidence of VTE among mechanically ventilated adults with COVID-19 pneumonia, compared to patients with respiratory failure related to other causes. Prospective study that enrolled critically ill adults with suspected COVID-19 pneumonia between June 2, 2020 and August 11, 2020. Critically ill adults with suspected COVID-19 pneumonia who required mechanical ventilation within 24 h after hospital admission were followed until death or hospital discharge. Sequential ultrasonography screening of the lower extremities and catheter insertion sites, as well as testing for plasma biochemical markers, were performed at the intensive care unit admission, day 3, day 7, and day 14. The primary outcome was a composite of deep venous thrombosis, pulmonary embolism, and thrombosis at the central catheter insertion sites. We enrolled 70 patients, including 57 patients with COVID-19 and 13 patients without COVID-19, and all patients completed follow-up. The incidence of the primary outcome was higher among patients with COVID-19 than among patients with respiratory failure related to other etiologies (36.8% vs. 0%, p = 0.023). Multivariate regression analysis revealed that VTE was independently associated with a COVID-19 diagnosis (odds ratio: 6.28, 95% confidence interval: 1.19-68.07) and D-dimer concentration (1-ng/mL increase, odds ratio: 1.15, 95% confidence interval: 1.05-1.30). The incidence of VTE was higher among critically ill mechanically ventilated patients, relative to among patients with respiratory failure related to other causes.

Constitutive expression of Arabidopsis bZIP transcription factor AREB1 activates cross-signaling responses in soybean under drought and flooding stresses.

Abiotic stress, such as drought and flooding, are responsible for considerable losses in grain production worldwide. Soybean, the main cultivated oilseed in the world, is sensitive to both stresses. Plant molecular mechanisms answer via crosstalk of several signaling pathways, in which particular genes can respond to different stresses. Previous studies confirmed that overexpression of transcription factor AtAREB1 confers drought tolerance in soybean. However, plants containing this gene have not yet been tested under flooding. Thus, the objective of this study was to characterize genetically modified (GM) soybean plants overexpressing AtAREB1 under drought and flooding conditions in comparison to its genetic background. Physiological and biochemical measurements were performed. In addition, the expression level of genes commonly activated under both stresses was evaluated. The results supported the role of the AtAREB1 gene in conferring tolerance to water deficit in soybeans. Furthermore, under flooding, the GM line was efficient in maintaining a higher photosynthetic rate, intrinsic efficiency in water use, and instantaneous carboxylation efficiency, resulting in higher grain yield under stress. The GM line also presented higher protein content, lower concentration of hydrogen peroxide, and lower expression levels of genes related to fermentative metabolism and alanine biosynthesis. These results indicate that in addition to drought stress, plants overexpressing AtAREB1 exhibited better performance under flooding when compared to the non-GM line, suggesting a cross-signaling response to both abiotic factors.

The response of plant functional traits to aridity in a tropical dry forest.

Drylands are experiencing an overall increase in aridity that is predicted to intensify in the future due to climate change. This may cause changes in the structure and functioning of dryland ecosystems, affecting ecosystem services and human well-being. Therefore, detecting early signs of ecosystem change before irreversible damage takes place is important. Thus, here we used a space-for-time substitution approach to study the response of the plant community to aridity in a Tropical dry forest (Caatinga, Brazil), and infer potential consequences of climate change. We assessed plant functional structure using the community weighted mean (CWM) and functional diversity, measured through functional dispersion (FDis), along a 700 km climatic gradient. We studied 13 functional traits, reflecting strategies associated with establishment, defense, regeneration, and dispersal of the most abundant 48 plant species in 113 sampling sites. Spearman correlations were used to test the relation between aridity and single-trait functional metrics. Aridity was a major environmental filter of the plant community functional structure. We found a higher abundance of species with deciduous leaves, zoochorous dispersal, fleshy fruits, chemical defense exudation and spinescence, and crassulacean acid metabolism towards more arid sites, at the expense of species with evergreen and thicker leaves, autochory dispersal, and shrub growth-form. The FDis of leaf type and thickness decreased with aridity, whereas FDis of fruit type, photosynthetic pathway, and defense strategies increased. Our findings provide functional indicators to early detect climate change impacts on Caatinga structure and functioning, to timely adopt preventive measures (e.g. conservation of forest remnants) and restoration actions (e.g. introduction of species with specific functional traits) in this threatened and unique ecosystem.

Utility and limitations of APRI and FIB4 to predict staging in a cohort of nonselected outpatients with hepatitis C.

BACKGROUND: Chronic hepatitis C(CHC) staging is important for therapeutic decision-making. Identification of noninvasive markers can provide alternatives to liver biopsy. AIM: To assess the value of APRI and FIB4 for CHC fibrosis staging in a cohort of nonselected outpatients from a referral center in Sao Paulo, Brazil. MATERIAL AND METHODS: Medical records of 798 adult outpatients were analyzed retrospectively. For calculations of APRI and FIB4, the original descriptions were considered, and markers were compared with degree of liver injury. RESULTS: Overall, 49.3% of participants were female, and mean age was 56.9 ± 12.5 years. Genotype 1 was predominant (71.7 vs. 23.7% genotype 3); 64% had significant fibrosis, 44% had advanced fibrosis, and 28% had cirrhosis. The areas under the receiver operating curve for significant fibrosis, advanced fibrosis, and cirrhosis, respectively, were 0.809, 0.819, and 0.815 for the APRI marker and 0.803, 0.836 and 0.852 for FIB4. Using the recommended cut off values, approximately 30-40% of the patients could not be classified. In the remainder, either APRI or FIB4 alone correctly diagnosed 80-85% of cases. Concomitant or consecutive use of both APRI and FIB4 increased the number of the cases correctly diagnosed only slightly, but also increased the number of patients not classified within the cutoff values. CONCLUSIONS: In conclusion, use of the APRI or FIB4 markers for detection of hepatic fibrosis may be a viable alternative at referral centers for treatment of CHC in low- and middle-income countries. Despite relatively good accuracy, a significant number of patients could not be assessed by these methods.

[The experience of a public institution in the training of health professionals to work in primary care]. / A experiência de uma instituição pública na formação do profissional de saúde para atuação em atenção primária.

This scope of this paper is to analyze the training of nurses and physicians to work in primary care at a public institution in the municipality of Marilia, duly identifying the concepts of professors, coordinators and graduates in relation to the formation of health professionals. It is a qualitative, exploratory study with interviews conducted with 21 individuals. The results revealed that according to the individuals interviewed, both courses prepare professionals to work in primary care, albeit with limitations in relation to actions in management collective and care. The interviewees believe that the use of active methodologies has been important in the teaching and learning process. Also, the fact that from the first year of undergraduate studies the students participate in primary health care broadens their knowledge of this reality. The study highlights the need to enhance the teaching-service partnership and strategies to improve the training physicians to work in primary health care.

Building a open source framework for virtual medical training.

This paper presents a framework to build medical training applications by using virtual reality and a tool that helps the class instantiation of this framework. The main purpose is to make easier the building of virtual reality applications in the medical training area, considering systems to simulate biopsy exams and make available deformation, collision detection, and stereoscopy functionalities. The instantiation of the classes allows quick implementation of the tools for such a purpose, thus reducing errors and offering low cost due to the use of open source tools. Using the instantiation tool, the process of building applications is fast and easy. Therefore, computer programmers can obtain an initial application and adapt it to their needs. This tool allows the user to include, delete, and edit parameters in the functionalities chosen as well as storing these parameters for future use. In order to verify the efficiency of the framework, some case studies are presented.

Diagnosis of obstructive sleep apnea syndrome and its outcomes with home portable monitoring.

BACKGROUND: The use of portable respiratory monitoring (PM) has been proposed for the diagnosis of obstructive sleep apnea syndrome (OSAS), but most studies that validate PM accuracy have not followed the best standards for diagnostic test validation. The objective of the present study was to evaluate the accuracy of PM performed at home to diagnose OSAS and its outcomes after first validating PM in the laboratory setting by comparing it to polysomnography (PSG). METHODS: Patients with suspected OSAS were submitted, in random order, to PM at the sleep laboratory concurrently with PSG (lab-PM) or at home-PM. The diagnostic performance was assessed by sensitivity, specificity, positive and negative predictive values, positive likelihood ratio (+LR), negative likelihood ratio (-LR), intraclass correlation coefficients, kappa statistic, and Bland-Altman plot. RESULTS: One hundred fifty-seven subjects (73% men, mean age +/- SD, 45 +/- 12 yr) with an apnea-hypopnea index (AHI) of 31 (SD +/- 29) events/h were studied. Excluding inadequate recordings, 149 valid comparisons with lab-PM and 121 with unattended home-PM were obtained. Compared to PSG for detecting AHI > 5, the lab-PM demonstrated sensitivity of 95.3%, specificity of 75%, +LR of 3.8, and -LR of 0.11; the home-PM exhibited sensitivity of 96%, specificity of 64%, +LR of 2.7, and -LR of 0.05. Kappa statistics indicated substantial correlation between PSG and PM results. Bland-Altman plot showed smaller dispersion for lab-PM than for home-PM. Pearson product moment correlation coefficients among the three AHIs and clinical outcomes were similar, denoting comparable diagnostic ability. CONCLUSIONS: This study used all available comparison methods to demonstrate accuracy of PM in-home recordings similar to that of repeated PSGs. PM increases the possibility of correctly diagnosing and effectively treating OSAS in populations worldwide.