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888 result(s) for "Castro, Luz"
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Afforestation or intense pasturing improve the ecological and economic value of abandoned tropical farmlands
Increasing demands for livelihood resources in tropical rural areas have led to progressive clearing of biodiverse natural forests. Restoration of abandoned farmlands could counter this process. However, as aims and modes of restoration differ in their ecological and socio-economic value, the assessment of achievable ecosystem functions and benefits requires holistic investigation. Here we combine the results from multidisciplinary research for a unique assessment based on a normalization of 23 ecological, economic and social indicators for four restoration options in the tropical Andes of Ecuador. A comparison of the outcomes among afforestation with native alder or exotic pine, pasture restoration with either low-input or intense management and the abandoned status quo shows that both variants of afforestation and intense pasture use improve the ecological value, but low-input pasture does not. Economic indicators favour either afforestation or intense pasturing. Both Mestizo and indigenous Saraguro settlers are more inclined to opt for afforestation. Restoration of abandoned farmlands has the potential to improve ecosystem functions and benefits. Using a multidisciplinary approach, Knoke et al . show that ecological and economic indicators favour either afforestation or intense pasturing of these abandoned areas in the tropical Andes.
Ecuadorian Banana Farms Should Consider Organic Banana with Low Price Risks in Their Land-Use Portfolios
Organic farming is a more environmentally friendly form of land use than conventional agriculture. However, recent studies point out production tradeoffs that often prevent the adoption of such practices by farmers. Our study shows with the example of organic banana production in Ecuador that economic tradeoffs depend much on the approach of the analysis. We test, if organic banana should be included in economic land-use portfolios, which indicate how much of the land is provided for which type of land-use. We use time series data for productivity and prices over 30 years to compute the economic return (as annualized net present value) and its volatility (with standard deviation as risk measure) for eight crops to derive land-use portfolios for different levels of risk, which maximize economic return. We find that organic banana is included in land-use portfolios for almost every level of accepted risk with proportions from 1% to maximally 32%, even if the same high uncertainty as for conventional banana is simulated for organic banana. A more realistic, lower simulated price risk increased the proportion of organic banana substantially to up to 57% and increased annual economic returns by up to US$ 187 per ha. Under an assumed integration of both markets, for organic and conventional banana, simulated by an increased coefficient of correlation of economic return from organic and conventional banana (ρ up to +0.7), organic banana holds significant portions in the land-use portfolios tested only, if a low price risk of organic banana is considered. We conclude that uncertainty is a key issue for the adoption of organic banana. As historic data support a low price risk for organic banana compared to conventional banana, Ecuadorian farmers should consider organic banana as an advantageous land-use option in their land-use portfolios.
Compositional diversity of rehabilitated tropical lands supports multiple ecosystem services and buffers uncertainties
High landscape diversity is assumed to increase the number and level of ecosystem services. However, the interactions between ecosystem service provision, disturbance and landscape composition are poorly understood. Here we present a novel approach to include uncertainty in the optimization of land allocation for improving the provision of multiple ecosystem services. We refer to the rehabilitation of abandoned agricultural lands in Ecuador including two types of both afforestation and pasture rehabilitation, together with a succession option. Our results show that high compositional landscape diversity supports multiple ecosystem services (multifunction effect). This implicitly provides a buffer against uncertainty. Our work shows that active integration of uncertainty is only important when optimizing single or highly correlated ecosystem services and that the multifunction effect on landscape diversity is stronger than the uncertainty effect. This is an important insight to support a land-use planning based on ecosystem services. Land use becomes more diverse when it considers uncertain interactions of multiple ecosystem services. Here, Knoke and colleagues show that uncertainty plays a larger role if ecosystem services are optimized only for a single service, or if services correlate.
Effects of carbohydrate intake and body composition on short-distance swimming performance in adolescents
Background This study aimed to evaluate the influence of carbohydrate intake and body composition on athletic performance in adolescent swimmersMethods A cross-sectional study was conducted with 22 adolescent swimmers (both sexes) from a sports center in Paraíba, Brazil. Pre- and post-training carbohydrate intake was assessed using 24-hour dietary recalls and compared against the International Society of Sports Nutrition (ISSN) guidelines. Body composition was estimated via skinfold measurements, using age- and sex-specific cutoff points. Swimming performance was assessed based on the time to complete a 25-meter front crawl. Performance was categorized as optimal ( < 15 s), good (15–16 s), or regular ( > 16 s). These thresholds were defined by the authors based on the distribution of swim times in the study sample. Statistical analysis was performed using IBM® SPSS® Statistics 20.0. Associations between categorical variables were tested using the Chi-square test, with significance set at p < 0.05.Results Although 60% of participants with a “good” body fat percentage demonstrated better performance, no statistically significant association was observed between body composition and swim time (p = 0.073). In contrast, participants who consumed carbohydrates in amounts exceeding ISSN recommendations before training showed significantly better performance (p = 0.003). Additionally, all participants whose pre-training carbohydrate intake was below the recommended levels demonstrated regular performance (p = 0.003).Conclusions While body fat percentage is a relevant marker of body composition, this study suggests that adequate pre-training carbohydrate intake may have a greater impact on swimming performance. These findings reinforce the importance of carbohydrate availability as a key nutritional strategy, particularly in sports requiring both immediate and sustained energy, such as swimming.
Potential miRNA Use as a Biomarker: From Breast Cancer Diagnosis to Metastasis
Breast cancer is the most common cancer in women. Despite advances in diagnosis and prognosis, distal metastases occur in these patients in up to 15% of cases within 3 years of diagnosis. The main organs in which BC metastasises are the bones, lungs, liver, and brain. Unfortunately, 90% of metastatic patients will die, making this an incurable disease. Researchers are therefore seeking biomarkers for diagnosis and metastasis in different organs. Optimally, such biomarkers should be easy to detect using, preferably, non-invasive methods, such as using miRNA molecules, which are small molecules of about 22 nt that have as their main function the post-transcriptional regulation of genes. Furthermore, due to their uncomplicated detection and reproducibility in the laboratory, they are a tool of complementary interest for diagnosis, prognosis, and treatment. With this in mind, in this review, we focus on describing the most current studies that propose using miRNA independently as a potential biomarker for the diagnosis and prediction of brain, lung, liver, and bone metastases, as well as to open a window of opportunity to deepen this area of study to eventually use miRNAs molecules in clinical practice for the benefit of BC patients.
Radiofrequency ablation combined with conductive fluid-based dopants (saline normal and colloidal gold): computer modeling and ex vivo experiments
Background The volume of the coagulation zones created during radiofrequency ablation (RFA) is limited by the appearance of roll-off. Doping the tissue with conductive fluids, e.g., gold nanoparticles (AuNPs) could enlarge these zones by delaying roll-off. Our goal was to characterize the electrical conductivity of a substrate doped with AuNPs in a computer modeling study and ex vivo experiments to investigate their effect on coagulation zone volumes. Methods The electrical conductivity of substrates doped with normal saline or AuNPs was assessed experimentally on agar phantoms. The computer models, built and solved on COMSOL Multiphysics, consisted of a cylindrical domain mimicking liver tissue and a spherical domain mimicking a doped zone with 2, 3 and 4 cm diameters. Ex vivo experiments were conducted on bovine liver fragments under three different conditions: non-doped tissue (ND Group), 2 mL of 0.9% NaCl (NaCl Group), and 2 mL of AuNPs 0.1 wt% (AuNPs Group). Results The theoretical analysis showed that adding normal saline or colloidal gold in concentrations lower than 10% only modifies the electrical conductivity of the doped substrate with practically no change in the thermal characteristics. The computer results showed a relationship between doped zone size and electrode length regarding the created coagulation zone. There was good agreement between the ex vivo and computational results in terms of transverse diameter of the coagulation zone. Conclusions Both the computer and ex vivo experiments showed that doping with AuNPs can enlarge the coagulation zone, especially the transverse diameter and hence enhance sphericity.
Large differences between observed and expected Ecuadorian deforestation from 2001 to 2009: a counterfactual simulation approach
Ensuring the integrity of the world’s forests is indispensable for mitigating climate change, combatting biodiversity loss, and protecting the livelihoods of rural communities. While many strategies have been developed to address deforestation across different geographic scales, measuring their impact against a fluctuating background of market-driven forest loss is notoriously challenging. In this article, we (1) asses deforestation in Ecuador using a dynamic, counterfactual baseline that excludes non-market factors, (2) identify periods of reduced and excess deforestation, and (3) assess the economic consequences of associated CO2 emissions using the social cost of carbon metric. We construct a counterfactual market-forces-only reference scenario by simulating heterogeneous profit-seeking agents making satisficing land-use allocation decisions under uncertainty. The model simulates a reference scenario for 2001–2022, a period encompassing dollarization, the beginning of a constitution granting inalienable rights to nature, and the launch of the largest payments for ecosystem services program in Ecuador’s history. On this period, total deforestation was approximately 20% lower than expected in a market-forces-only scenario (9540 vs.12,000 km2). The largest deviation occurred in 2001–2009, when observed deforestation was 43.6% lower than expected (3720 vs 6590 km2). From 2010 onwards, deforestation appears to be market-driven. We assess the economic value of avoided CO2 emissions at US $5.7 billion if the reduction is permanent, or US $3.1 billion considering a 1% risk of loss from 2022 onwards. We discuss contributing factors that likely shaped periods of reduced and excess deforestation and stress the need to use realistic baselines.
Modulation of HERV Expression by Four Different Encephalitic Arboviruses during Infection of Human Primary Astrocytes
Human retroelements (HERVs) are retroviral origin sequences fixed in the human genome. HERVs induction is associated with neurogenesis, cellular development, immune activation, and neurological disorders. Arboviruses are often associated with the development of encephalitis. The interplay between these viruses and HERVs has not been fully elucidated. In this work, we analyzed RNAseq data derived from infected human primary astrocytes by Zika (ZikV), Mayaro (MayV), Oropouche (OroV) and Chikungunya (ChikV) viruses, and evaluated the modulation of HERVs and their nearby genes. Our data show common HERVs expression modulation by both alphaviruses, suggesting conserved evolutionary routes of transcription regulation. A total of 15 HERVs were co-modulated by the four arboviruses, including the highly upregulated HERV4_4q22. Data on the upregulation of genes nearby to these elements in ChikV, MayV and OroV infections were also obtained, and interaction networks were built. The upregulation of 14 genes common among all viruses was observed in the networks, and 93 genes between MayV and ChikV. These genes are related to cellular processes such as cellular replication, cytoskeleton, cell vesicle traffic and antiviral response. Together, our results support the role of HERVs induction in the transcription regulation process of genes during arboviral infections.
Socio-demographic, dietary, exercise, and mental health factors associated with food addiction symptoms in university students
Introduction Food addiction is characterized by repeated and uncontrolled consumption of food, usually ultra-processed foods. Objective To investigate the impact of sociodemographic, health, lifestyle, and dietary factors on food addiction symptoms. Methods A total of 512 university students (both sexes, aged between 18 and 35 years) provided information on completion that included the variables include family income, physical activity, psychiatric and physical disorders, and alcohol, drug, and tobacco use. They also shared dietary information such as main meal types and whether they added salt to food. Food addiction symptoms were assessed using the Yale Food Addiction Scale 2.0. We used a multiple linear regression model was used to investigate predicted changes in the number of food addiction symptoms. Results The model hadshowed an adjusted R 2 adjusted of 0.167 (and p  < 0.001). Female sex ( B  = 0.506; p  = < 0.,0401), low family income (from low to moderate: B  = -0.803, p  = 0.,002; and from low to high: B  = -0.732, p  = 0.024), physical ( p  = 0,046) and psychiatric disorders ( B  = 1.062, p  < = 0.001,08), practice of physical activity ( B  = -0.682, p  = 0.009) and be in current dieting ( B  = 1.498, p  < 0.001) predicted morea use of tobacco and derivatives ( p  = 0,020) food addiction symptoms. ( p  = 0,018) ( p  = 0,025) consumes less than five meals a day ( p  < 0,001). Conclusion Food addiction symptoms were found to be a multifactorial phenomenon, associated with sociodemographic and economic status, diet, exercise, and mental health. The limitations of this study of this study includewere its cross-sectional design, lack ofno dietary consumption data, sample convenience sampling-based, self-selection bias, and simplification ed collection of dietary concerns.
Two-compartment mathematical modeling in RF tumor ablation: New insight when irreversible changes in electrical conductivity are considered
The objective was to explore variations of temperature distribution and coagulation zone size computed by a two-compartment radiofrequency ablation (RFA) model when including simultaneously reversible changes in the tissue electrical conductivity (σ) due to temperature and irreversible changes due to thermal coagulation. Two-compartment (tumor and healthy tissue) models were built and simulated. Reversible change of σ was modeled by a piecewise function characterized by increments of +1.5%/℃ up to 100 ℃, and a 100 times smaller value from 100 ℃ onwards. Irreversible changes of σ were modeled using an Arrhenius model. We assumed that both tumor and healthy tissue had a different initial σ value (as suggested by the experimental data in the literature) and tended towards a common value as thermal damage progressed (necrotized tissue). We modeled a constant impedance protocol based on 90 V pulses voltage and three tumor diameters (2, 3 and 4 cm). Computer simulations showed that the differences between both models were only 0.1 and 0.2 cm for axial and transverse diameters, respectively, and this small difference was reflected in the similar temperature distributions computed by both models. In view of the available experimental data on changes of electrical conductivity in tumors and healthy tissue during heating, our results suggest that irreversible changes in electrical conductivity do not have a significant impact on coagulation zone size in two-compartment RFA models.