Abstract
Three-dimensional hydrodynamic simulations are commonly used to study the evolution of the gaseous content in isolated galaxies, besides its connection with galactic star formation ...histories. Stellar winds, supernova blasts, and black hole feedback are mechanisms usually invoked to drive galactic outflows and decrease the initial galactic gas reservoir. However, any simulation imposes the need of choosing the limits of the simulated volume, which depends, for instance, on the size of the galaxy and the required numerical resolution, besides the available computational capability to perform it. In this work, we discuss the effects of boundary conditions on the evolution of the gas fraction in a small-sized galaxy (tidal radius of ∼1 kpc), like classical spheroidal galaxies in the Local Group. We found that open boundaries with sizes smaller than approximately 10 times the characteristic radius of the galactic dark-matter halo become unappropriated for this kind of simulation after ∼0.6 Gyr of evolution, since they act as an infinity reservoir of gas due to dark-matter gravity. We also tested two different boundary conditions that avoid gas accretion from numerical frontiers: closed and selective boundary conditions. Our results indicate that the later condition (that uses a velocity threshold criterion to open or close frontiers) is preferable since it minimizes the number of reversed shocks due to closed boundaries. Although the strategy of putting computational frontiers as far as possible from the galaxy itself is always desirable, simulations with a selective boundary condition can lead to similar results at lower computational costs.
Background/Aims: Assessing the diet and biochemical indicators of vitamin A deficiency (VAD) in high-risk populations is crucial in cases where this deficiency is mainly caused by chronically ...inadequate intake. This study aimed to determine the retinol and betacarotene status in mother-infant dyads, and to evaluate the associations between them. Methods: Umbilical cord serum, maternal serum, and colostrum were collected from 134 healthy mothers living in a risk region for VAD. Vitamin A and betacarotene were quantified by liquid chromatography, and dietary information was collected using a food frequency questionnaire. Results: Although the overall mean intakes of vitamin A and betacarotene were considered adequate, 16% of the women had insufficient intake. Mean retinol levels were also adequate, yet low levels were diagnosed in about 8% of the mothers, based on maternal serum and colostrum, and in 16% of the cord serum samples. Retinol and betacarotene were positively associated in cord serum (p = 0.004), maternal serum (p = 0.041), and colostrum (p < 0.001) but was not associated with dietary intake. Conclusions: A diagnosis of adequacy based on mean biochemical and dietary data of this population in fact masks the marginal vitamin A status presented by mothers and children.
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•Divaricatic acid exhibits toxicity against B. glabrata embryos and adult snails.•Malformations and delay in embryonic development were observed.•Divaricatic acid showed lethal ...effects against cercariae of Schistosoma mansoni.•Divaticatic acid was not toxic to Artemia salina.
In this study, the molluscicidal and antiparasitic activities of divaricatic acid was evaluated, targeting the mollusc Biomphalaria glabrata and cercariae of the helminth Schistosoma mansoni. In addition, the environmental toxicity of divaricatic acid was assessed by bioassay using the microcrustacean Artemia salina. Divaricatic acid showed high toxicity against both adult snails (5μg/mL) and embryos (20μg/mL after 6h of exposure). Similar activity was observed in Schistosoma mansoni cercariae after only a short exposure time (10μg/mL after 30min of exposure). The divaricatic acid did not show toxicity in the acute test using Artemia salina at concentrations equal to or below 200μg/mL. The divaricatic acid proved to be a promising substance for the elimination of the snail Biomphalaria glabrata, an intermediate host of schistosomiasis, as well as the cercariae of the pathogen, while being non-toxic to the Artemia salina at the same concentrations. This is the first experimental observation of the molluscicidal and cercaricide activity of divaricatic acid.
While biogas production offers promising solutions for waste management, energy diversification, and sustainable development, effective project implementation requires comprehensive evaluation ...criteria that encompass diverse aspects, such as the problem to be addressed, biodigester technology selection, business model development, investment considerations, and final product utilization. A preliminary study involving an integrative review of 58 articles yielded 499 unique criteria. These criteria were categorized into four groups: economic, environmental, social, and technical, encompassing a total of 39 subcriteria. Six stages of the biogas production cycle were considered in the analysis: project, initiation, biodigester type selection, location determination, operational cycle definition, and final product utilization. The analysis revealed that existing decision-making models often prioritize technical and economic considerations while neglecting broader social and environmental perspectives. This paper addresses this gap by proposing, for the first time, stage-specific, multicriteria decision-making (MDCA) models tailored to each phase of a biogas production cycle. These models empower project managers and policymakers to optimize resource allocation, minimize the environmental impact, maximize social benefits, and ensure project viability and profitability. The models’ adaptability allows for tailored prioritization based on specific project requirements and contexts. This groundbreaking research fills a critical void in biogas decision making by bridging the gap between existing technical and economic model limitations and the growing need for truly sustainable project development.
Many real-world systems can be studied in terms of pattern recognition tasks, so that proper use (and understanding) of machine learning methods in practical applications becomes essential. While ...many classification methods have been proposed, there is no consensus on which methods are more suitable for a given dataset. As a consequence, it is important to comprehensively compare methods in many possible scenarios. In this context, we performed a systematic comparison of 9 well-known clustering methods available in the R language assuming normally distributed data. In order to account for the many possible variations of data, we considered artificial datasets with several tunable properties (number of classes, separation between classes, etc). In addition, we also evaluated the sensitivity of the clustering methods with regard to their parameters configuration. The results revealed that, when considering the default configurations of the adopted methods, the spectral approach tended to present particularly good performance. We also found that the default configuration of the adopted implementations was not always accurate. In these cases, a simple approach based on random selection of parameters values proved to be a good alternative to improve the performance. All in all, the reported approach provides subsidies guiding the choice of clustering algorithms.
The decision to implement a biogas production project involves the evaluation of multiple variables, such as the problem to be solved, the biodigester, business model, investment, and final products. ...An integrative literature review was conducted, in which 58 papers were obtained and relevant criteria for decision-making in biogas production projects from organic waste were identified. Three stages were considered in the analysis of the biogas production cycle: initial, plant, and final, as well as the economic, environmental, and social aspects that influence the decision. In general, the publications are dispersed over 30 different journals. The methodology used in most studies is empirical, quantitative, and descriptive, with data collected mainly from secondary sources. From the studies, 499 original criteria were identified, which were classified into one of four categories: economic, environmental, social, and technical, which cover a total of 39 sub-criteria. Economic and technical criteria were the most frequent in publications, while environmental and social criteria were less common and less prioritized. This suggests that there is a tendency to prioritize economic and technical dimensions over environmental and social dimensions in the analysis of the papers found. Finally, a preliminary decision-making model based on the findings is proposed.
Implications: The integrative review of the literature on biogas and decision-making presented in this study holds significant implications for policy and practice in the field of sustainable energy production, organic waste management and decision making for public managers. By analyzing 159 papers and developing a comprehensive classification system, we have identified key sub-criteria for decision-making in various stages of the biogas production cycle. The predominance of technical and economic sub-criteria demonstrates the priorities of the current state of biogas projects and, at the same time, the need to promote balance between the technical, economic, social and environmental spheres in decision-making in order to achieve truly sustainable biogas projects. Policymakers can utilize these findings to promote the adoption of more holistic decision-making approaches that consider diverse factors, fostering the development of environmentally-friendly and socially equitable biogas ventures. This research provides valuable insights into aligning biogas production with broader sustainability goals and guides policymakers in formulating evidence-based strategies for the advancement of renewable energy technologies.
Worldwide, extensive agricultural losses are attributed to drought, often in combination with heat in Mediterranean climate regions, where grapevine traditionally grows. The available scenarios for ...climate change suggest increases in aridity in these regions. Under natural conditions plants are affected by a combination of stresses, triggering synergistic or antagonistic physiological, metabolic or transcriptomic responses unique to the combination. However the study of such stresses in a controlled environment can elucidate important mechanisms by allowing the separation of the effects of individual stresses. To gather those effects, cuttings of two grapevine varieties, Touriga Nacional (TN) and Trincadeira (TR), were grown under controlled conditions and subjected to three abiotic stresses (drought – WS, heat – HS and high light – LS) individually and in combination two‐by‐two (WSHS, WSLS, HSLS) or all three (WSHSLS). Photosynthesis, water status, contents of H2O2, abscisic acid and metabolites of the ascorbate‐glutathione cycle were measured in the leaves. Common and distinct response features were identified in the different stress combinations. Photosynthesis was not hindered in TN by LS, while even individual stresses severely affect photosynthesis in TR. Abscisic acid may be implicated in grapevine osmotic responses since it is correlated with tolerance parameters, especially in combined stresses involving drought. Overall, the responses to drought‐including treatments were clearly distinct to those without drought. From the specific behaviours of the varieties, it can be concluded that TN shows a higher capacity for heat dissipation and for withstanding high light intensities, indicating better adjustment to warm conditions, provided that water supply is plentiful.
The impact on cell wall (CW) of the deficiency in nitrogen (–N), phosphorus (–P) or sulphur (–S), known to impair essential metabolic pathways, was investigated in the economically important fruit ...species
Vitis vinifera
L. Using cuttings as an experimental model a reduction in total internode number and altered xylem shape was observed. Under –N an increased internode length was also seen. CW composition, visualised after staining with calcofluor white, Toluidine blue and ruthenium red, showed decreased cellulose in all stresses and increased pectin content in recently formed internodes under –N compared to the control. Using CW-epitope specific monoclonal antibodies (mAbs), lower amounts of extensins incorporated in the wall were also observed under –N and –P conditions. Conversely, increased pectins with a low degree of methyl-esterification and richer in long linear 1,5-arabinan rhamnogalacturonan-I (RG-I) side chains were observed under –N and –P in mature internodes which, in the former condition, were able to form dimeric association through calcium ions. –N was the only condition in which 1,5-arabinan branched RG-I content was not altered, as –P and –S older internodes showed, respectively, lower and higher amounts of this polymer. Higher xyloglucan content in older internodes was also observed under –N. The results suggest that impairments of specific CW components led to changes in the deposition of other polymers to promote stiffening of the CW. The unchanged extensin amount observed under –S may contribute to attenuating the effects on the CW integrity caused by this stress. Our work showed that, in organized
V. vinifera
tissues, modifications in a given CW component can be compensated by synthesis of different polymers and/or alternative linking between polymers. The results also pinpoint different strategies at the CW level to overcome mineral stress depending on how essential they are to cell growth and plant development.
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