2,658 research outputs found
Primary Production and Nutrient Content in Two Salt Marsh
Seasonal variation patterns of aboveground and belowground biomass, net primary production, and nutrient
accumulation were assessed in Atriplex portulacoides L. and Limoniastrum monopetalum (L.) Boiss. in Castro Marim salt marsh,
Portugal. Sampling was conducted for five periods during 2001–2002 (autumn, winter, spring, summer, and autumn). This
study indicates that both species have a clear seasonal variation pattern for both aboveground and belowground biomass.
Mean live biomass was 2516 g m22 yr21 for L. monopetalum and 598 g m22 yr21 for A. portulacoides. Peak living biomass, in
spring for both species, was three times greater in the former, 3502 g m22 yr21, than in the latter, 1077 g m22 yr21. For both
the Smalley (Groenendijk 1984) and Weigert and Evans (1964) methods, productivity of L. monopetalum (2917 and
3635 g m22 yr21, respectively) was greater than that of A. portulacoides (1002 and 1615 g m22 yr21, respectively). Belowground
biomass of L. monopetalum was 1.7 times greater than that of A. portulacoides. In spite of this, the root:shoot ratio for A.
portulacoides was greater throughout the year. This shows that A. portulacoides allocates more biomass to roots and L.
monopetalum to aerial components. Leaf area index was similar for both species, but specific leaf area of A. portulacoides was
twice that of L. monopetalum. The greatest nutrient contents were found in leaves. Leaf nitrogen content was maximum in
summer for both species (14.6 mg g21 for A. portulacoides and 15.5 mg g21 for L. monopetalum). Leaf phosphorus
concentration was minimum in summer (1.1 mg g21 in A. portulacoides and 1.2 mg g21 in L. monopetalum). Leaf potassium
contents in A. portulacoides were around three times greater than in L. monopetalum. Leaf calcium contents in L. monopetalum
were three times greater than in A. portulacoides. There was a pronounced seasonal variation of calcium content in the former,
while in the latter no clear variation was registered. Both species exhibited a decrease in magnesium leaf contents in the
summer period. Manganese content in L. monopetalum leaves was tenfold that in A. portulacoides. Seasonal patterns of nutrient
contents in A. portulacoides and L. monopetalum suggest that availability of these elements was not a limiting factor to biomass production
Lower Extremity Burns with Bone Exposure: Reconstruction with Dermal Regeneration Template
Introdução: As soluções reconstrutivas das queimaduras dos membros inferiores com exposição óssea (transferência de tecidos vascularizados) e dos defeitos do escalpe, não susceptÃveis de encerramento com retalhos locais (expansão tecidual), são complexas, morosas e, por vezes,
inviáveis. O recurso a substitutos cutâneos biológicos, como a matriz de regeneração dérmica, constitui uma importante alternativa às soluções reconstrutivas tradicionais. Relato dos casos:
Estudo retrospectivo de 246 doentes com queimaduras dos membros inferiores, admitidos na Unidade de Queimados/Serviço de Cirurgia Plástica do nosso Centro Hospitalar, entre Janeiro de 2007 e Dezembro de 2008. Os autores apresentam 2 casos clÃnicos com queimaduras bilaterais
das pernas e com exposição óssea. Nos dois casos, realizou-se desbridamento tangencial e encerramento das áreas cruentas com um substituto cutâneo, a matriz de regeneração dérmica. Na 4ª semana após a aplicação da matriz, o componente externo da membrana bilaminar foi substituÃdo por enxerto de pele parcial. Obteve-se cobertura estável das áreas cruentas, sem necessidade de
procedimentos cirúrgicos adicionais. Conclusões: A utilização de substitutos dérmicos expande as opções reconstrutivas nos casos de queimaduras com exposição óssea dos membros inferiores. A utilização da matriz biológica permitiu a preservação dos membros nos dois pacientes. A matriz
de regeneração dérmica possibilitou uma cobertura estável de estruturas vitais, sem necessidade de transferência ou expansão tecidual e com morbilidade mÃnima
Avaliação das Vasculopatias Não Ateroscleróticas por Ecografia-Doppler
The non-atherosclerotic vasculopathies are an uncommon group of disorders, with diverse etiopathogenesis, involving younger patients when compared with atherosclerotic disease. Clinical presentation varies from acute vascular events - ischemic or hemorrhagic- to uncharacteristic neurologic syndromes.
Although the cerebral angiography is the gold standard diagnostic method due to its high sensibility, its specificity is low mainly when compared to imaging evaluation of the arterial wall with carotid and vertebral ultrasound-doppler. We reinforce the importance of this non-invasive and radiation-free exam, not only in the diagnosis but also in the monitoring of these patients - young patients who need a regular and extended evaluationinfo:eu-repo/semantics/publishedVersio
Towards fast machine-learning-assisted Bayesian posterior inference of microseismic event location and source mechanism
Bayesian inference applied to microseismic activity monitoring allows the accurate location of microseismic events from recorded seismograms and the estimation of the associated uncertainties. However, the forward modelling of these microseismic events, which is necessary to perform Bayesian source inversion, can be prohibitively expensive in terms of computational resources. A viable solution is to train a surrogate model based on machine learning techniques, to emulate the forward model and thus accelerate Bayesian inference. In this paper, we substantially enhance previous work, which considered only sources with isotropic moment tensors. We train a machine learning algorithm on the power spectrum of the recorded pressure wave and show that the trained emulator allows complete and fast event locations for any source mechanism. Moreover, we show that our approach is computationally inexpensive, as it can be run in less than 1Â hour on a commercial laptop, while yielding accurate results using less than 104 training seismograms. We additionally demonstrate how the trained emulators can be used to identify the source mechanism through the estimation of the Bayesian evidence. Finally, we demonstrate that our approach is robust to real noise as measured in field data. This work lays the foundations for efficient, accurate future joint determinations of event location and moment tensor, and associated uncertainties, which are ultimately key for accurately characterising human-induced and natural earthquakes, and for enhanced quantitative seismic hazard assessments
Group Differences Between Countries and Between Languages in Pain-Related Beliefs, Coping, and Catastrophizing in Chronic Pain: A Systematic Review
Objective: To evaluate the extent to which pain-related beliefs, appraisals, coping, and catastrophizing differ between countries, language groups, and country economy. /
Design: Systematic review. /
Methods: Two independent reviewers searched 15 databases without restriction for date or language of publication. Studies comparing pain beliefs/appraisals, coping, or catastrophizing across two or more countries or language groups in adults with chronic pain (pain for longer than three months) were included. Two independent reviewers extracted data and performed the quality appraisal. Study quality was rated as low, moderate, or high using a 10-item modified STROBE checklist. Effect sizes were reported as small (0.20–0.49), medium (0.50–0.79), or large (≥0.80). /
Results: We retrieved 1,365 articles, read 42 potential full texts, and included 10 (four moderate-quality, six low-quality) studies. A total of 6,797 adults with chronic pain (33% with chronic low back pain) were included from 16 countries. Meta-analysis was not performed because of heterogeneity in the studies. A total of 103 effect sizes were computed for individual studies, some of which indicated between-country differences in pain beliefs, coping, and catastrophizing. Of these, the majority of effect sizes for pain beliefs/appraisal (60%; eight large, eight medium, and eight small), for coping (60%; seven large, 11 medium, and 16 small), and for catastrophizing (50%; two medium, one small) evidenced statistically significant between-country differences, although study quality was low to moderate. /
Conclusions: In 50% or more of the studies, mean scores in the measures of pain beliefs and appraisals, coping responses, and catastrophizing were significantly different between people from different countries
The use of system dynamics for energy and environmental education
The use of system dynamics as a learning tool for developing sustainable energy strategies and environmental education has advanced in recent years with the availability of new modelling software and webtools. Among the existing models, we highlight the online 2050 Calculators, which aim at simulating scenarios for greenhouse gas emissions, energy planning, sustainable land use, and food consumption. The objective of this study is to assess the available calculators and their contribution to an interdisciplinary education via systems thinking. We carried out a review of the existing models worldwide and ran some of the tools with students from three different postgraduate programmes at master’s level at Imperial College London (United Kingdom) and IFP School (France), whilst also assessing their individual views afterwards. The assessments were conducted once a year during three subsequent years: 2019, 2020, and 2021. The results are discussed under the epistemology of critical pedagogy, showing that the use of webtools, such as the 2050 Calculators, can significantly contribute to the students’ environmental awareness and political engagement, providing important lessons about the use of system dynamics for policy and science education
Chronic breathlessness and sleep problems: a population-based survey
ObjectivesThis study aimed to explore the relationship (presence and severity) between chronic breathlessness and sleep problems, independently of diagnoses and health service contact by surveying a large, representative sample of the general population.SettingAnalysis of the 2017 South Australian Health Omnibus Survey, an annual, cross-sectional, face-to-face, multistage, clustered area systematic sampling survey carried out in Spring 2017.Chronic breathlessness was self-reported using the ordinal modified Medical Research Council (mMRC; scores 0 (none) to 4 (housebound)) where breathlessness has been present for more than 3 of the previous 6 months. 'Sleep problems-ever' and 'sleep problem-current' were assessed dichotomously. Regression models were adjusted for age; sex and body mass index (BMI).Results2900 responses were available (mean age 48.2 years (SD=18.6); 51% were female; mean BMI 27. 1 (SD=5.9)). Prevalence was: 2.7% (n=78) sleep problems-past; 6.8% (n=198) sleep problems-current and breathlessness (mMRC 1-4) was 8.8% (n=254). Respondents with sleep problemspast were more likely to be breathless, older with a higher BMI and sleep problems-present also included a higher likelihood of being female.After adjusting for age, sex and BMI, respondents with chronic breathlessness had 1.9 (95% CI=1.0 to 3.5) times the odds of sleep problems-past and sleep problems-current (adjusted OR=2.3; 95% CI=1.6 to 3.3).ConclusionsThere is a strong association between the two prevalent conditions. Future work will seek to understand if there is a causal relationship using validated sleep assessment tools and whether better managing one condition improves the other
Individuals with type 2 diabetes have higher density of small intestinal neurotensin-expressing cells
Neurotensin (NT) is a gastro-intestinal hormone involved in several pathways that regulate energy and glucose homeostasis. NT was hypothesized to act in synergy with incretin hormones to potentiate its anti-diabetic effects. Additionally, circulating NT levels were shown to rise after bariatric surgery-induced weight loss. Knowledge of NT-secreting cells distribution along the small intestine and its variation according to diabetes status could provide insights on NT role in mediating type 2 diabetes (T2D) improvement after bariatric surgery. So, our aims were to characterize NT-expressing cell distribution along the human small intestine and to compare the relative density of NT-expressing cells in the small intestine of individuals with and without T2D undergoing bariatric surgery for obesity treatment. Autopsy-derived small intestine fragments (n = 30) were obtained at every 20Â cm along the entire intestinal length. Additionally, jejunum biopsies (n = 29) were obtained during elective gastric bypass interventions from patients with (n = 10) or without T2D (n = 18). NT-expressing cells were identified by immunohistochemistry and quantified via computerized morphometric analysis. NT-expressing cell density increased along the human small intestine. NT-expressing cell density was significantly higher from 200Â cm distal to the duodenojejunal flexure onward, as well as in subjects with T2D when compared to those without T2D. NT-expressing cell density increases along the human small gut, and a higher density is found in individuals with T2D. This finding suggests a potential role for NT in the mechanisms of disease and T2D improvement observed after bariatric surgery. (c) 2023, The Author(s)
Mineralocorticoid receptor antagonists eplerenone and spironolactone modify adrenal cortex morphology and physiology
Mineralocorticoid receptor antagonists (MRAs) are a class of anti-hypertensive drugs that act by blocking aldosterone action. The aim of this study was to evaluate whether the MRAs spironolactone and eplerenone influence adrenal cortical physiology and morphology. Spontaneous hypertensive rats (SHR, n = 18) and normotensive rats (WKY, n = 18) were randomly exposed to a daily dose of spironolactone (n = 6), eplerenone (n = 6), or no drug (n = 6) over 28 days. After that, aldosterone, corticosterone, and 11-deoxycorticosterone plasma concentrations were quantified. Adrenal glands were subjected to morphological analysis to assess lipid droplets content, capsular width, cell proliferation, and steroidogenic proteins expression. The adrenal cortex in untreated SHR showed higher lipid droplet content as than in WKY. In SHR, MRA treatment was associated with higher circulating aldosterone levels and Ki-67 expression in aldosterone-secreting cells. In WKY, the only difference observed after MRA spironolactone treatment was a narrower capsule. There was no difference in abundance of steroidogenic enzyme between groups. In conclusion, MRAs modify adrenal gland function and morphology in SHR. The effects observed within the adrenal glomerulosa with aldosterone-secreting cell proliferation and higher circulating aldosterone levels suggests that MRA treatment provokes activation of the renin angiotensin system. The prognostic value of hyperaldosteronism secondary to MRAs blockade requires further investigation.Funding: This research was funded by the Associação dos Amigos do Serviço de Endocrinologia do Hospital de São João (2020–2021). Unit for Multidisciplinary Research in Biomedicine (UMIB) is funded by the Foundation for Science and Technology (FCT)-Portugal (UIDB/00215/2020 and UIDP/00215/2020—approval date: 2019)
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