Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 41
Filtrar
1.
Food Technol Biotechnol ; 62(1): 26-34, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38601966

RESUMO

Research background: Enzymatically resistant maltodextrins (ERM) are a resistant starch type 4, synthesized from native starch. They are obtained by the sequential application of two processes: pyrodextrinization, which produces pyrodextrins, and enzymatic hydrolysis, which produces ERM. In these processes atypical bonds are formed that confer pyrodextrins and ERM similar properties to dietary fiber, such as resistance to digestion. The aim of this work is to determine and evaluate some physicochemical properties of pyrodextrins and ERM obtained from native starch isolated from makal (Xanthosoma yucatanense) tubers. Experimental approach: Pyrodextrinization and complementary hydrolysis were conducted using factorial designs. For pyrodextrinization, factors and their levels were (m(starch):V(HCl))=80:1 and 160:1 (c(HCl)=2.2 M), temperature 90 and 110 °C and reaction time 1 and 3 h, and for CH, α-amylase per pyrodextrin volume fractions 0.5 and 1 µL/mL and reaction time 10 and 30 min. The physicochemical profile included determination of resistant starch content, estimation of color change (ΔE), microscopy and determination of dextrose equivalents (DE). Results and conclusions: According to the factorial design, the best treatment conditions for pyrodextrinization were: (m(starch):V(HCl))=160:1, 90 °C and 3 h, since they resulted in the highest resistant starch content (84.73 %) and the lowest ΔE (3.742). Due to the low DE (13.89 %), increased amount of resistant starch (90.73 %) and low ΔE (4.24) in the resulting ERM, complementary hydrolysis with α-amylase per pyrodextrin volume fraction 0.5 µL/mL and hydrolysis time 10 min was selected as the best treatment. Novelty and scientific contribution: The results show that the pyrodextrins and ERM obtained from makal can be used as ingredients for the development of functional foods, due to their high content of indigestible material and low degree of browning.

2.
Intern Emerg Med ; 19(4): 1089-1098, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38466555

RESUMO

To investigate whether the timing of a previous hospital admission for acute heart failure (AHF) is a prognostic factor for AHF patients revisiting the emergency department (ED) in the subsequent 12-month follow-up. All ED AHF patients enrolled in the previously described EAHFE registry were stratified by the presence or absence of an AHF hospitalization admission in the prior 12 months. The primary outcome was 12-month all-cause mortality post ED visit. Secondary end points were hospital admission, prolonged hospitalization (> 7 days), mortality during hospitalization and a 90-day post-discharge adverse composite event (ACE) rate, defined as ED revisits due to AHF, hospitalizations due to AHF, or all-cause mortality. Outcomes were adjusted for baseline and AHF episode characteristics.Of 5,757 patients included, the median age was 84 years (IQR 77-88); 57% were women, and 3,759 (65.3%) had an AHF hospitalization in the previous 12 months. The 12-month mortality was 37% (41.7% vs. 28.3% p < 0.001), hospital admission was 76.1% (78.8% vs. 71.1% p < 0.001) ACE was 60.2% (65.1% vs. 50.5% p < 0.001). In the adjusted analysis, patients with AHF hospitalization in the prior 12 months had a higher mortality (HR = 1.41; 95% CI 1.27-1.56), 90-day ACE rate (HR = 1.45: 95% CI 1.32-1.59), and more hospital admissions (OR = 1.32; 95% CI 1.16-1.51), with shorter times since the previous hospitalization being related to the outcomes analyzed. One-year mortality, adverse events at 90 days, and readmission rates are increased in ED AHF patients previously admitted within the last 12 months.


Assuntos
Serviço Hospitalar de Emergência , Insuficiência Cardíaca , Hospitalização , Humanos , Feminino , Insuficiência Cardíaca/mortalidade , Masculino , Serviço Hospitalar de Emergência/estatística & dados numéricos , Serviço Hospitalar de Emergência/organização & administração , Idoso , Idoso de 80 Anos ou mais , Hospitalização/estatística & dados numéricos , Prognóstico , Fatores de Tempo , Sistema de Registros/estatística & dados numéricos , Readmissão do Paciente/estatística & dados numéricos
3.
Antioxidants (Basel) ; 12(11)2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-38001809

RESUMO

Excessive consumption of fat and carbohydrates, together with a decrease in traditional food intake, has been related to obesity and the development of metabolic alterations. Ramon seed is a traditional Mayan food used to obtain Ramon flour (RF) with high biological value in terms of protein, fiber, micronutrients, and bioactive compounds such as polyphenols. However, few studies have evaluated the beneficial effects of RF. Thus, we aimed to determine the metabolic effects of RF consumption on a high-fat-diet-induced obesity mouse model. We divided male BALB/c mice into four groups (n = 5 each group) and fed them for 90 days with the following diets: Control (C): control diet (AIN-93), C + RF: control diet adjusted with 25% RF, HFD: high-fat diet + 5% sugar in water, and HFD + RF: high-fat diet adjusted with 25% RF + 5% sugar in water. The RF prevented the increase in serum total cholesterol (TC) and alanine transaminase (ALT) that occurred in the C and HFD groups. Notably, RF together with HFD increased serum polyphenols and antioxidant activity, and it promoted a decrease in the adipocyte size in white adipose tissue, along with lower hepatic lipid accumulation than in the HFD group. In the liver, the HFD + RF group showed an increase in the expression of ß-oxidation-related genes, and downregulation of the fatty acid synthase (Fas) gene compared with the HFD group. Moreover, the HFD + RF group had increased hepatic phosphorylation of AMP-activated protein kinase (AMPK), along with increased nuclear factor erythroid 2-related factor 2 (NRF2) and superoxide dismutase 2 (SOD2) protein expression compared with the HFD group. Thus, RF may be used as a nutritional strategy to decrease metabolic alterations during obesity.

4.
Int J Neural Syst ; 33(12): 2350065, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37857407

RESUMO

Reinforcement learning (RL) is a powerful technique that allows agents to learn optimal decision-making policies through interactions with an environment. However, traditional RL algorithms suffer from several limitations such as the need for large amounts of data and long-term credit assignment, i.e. the problem of determining which actions actually produce a certain reward. Recently, Transformers have shown their capacity to address these constraints in this area of learning in an offline setting. This paper proposes a framework that uses Transformers to enhance the training of online off-policy RL agents and address the challenges described above through self-attention. The proposal introduces a hybrid agent with a mixed policy that combines an online off-policy agent with an offline Transformer agent using the Decision Transformer architecture. By sequentially exchanging the experience replay buffer between the agents, the agent's learning training efficiency is improved in the first iterations and so is the training of Transformer-based RL agents in situations with limited data availability or unknown environments.


Assuntos
Aprendizagem , Reforço Psicológico , Recompensa , Algoritmos
5.
J Card Fail ; 29(5): 734-744, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36706976

RESUMO

OBJECTIVE: To investigate the relationship of seasonal flu vaccination with the severity of decompensation and long-term outcomes of patients with heart failure (HF). METHODS: We analyzed 6147 consecutively enrolled patients with decompensated HF who presented to 33 Spanish emergency departments (EDs) during January and February of 2018 and 2019, grouped according to seasonal flu vaccination status. The severity of HF decompensation was assessed by the Multiple Estimation of Risk Based on the Emergency Department Spanish Score in Patients With Acute Heart Failure (MEESSI-AHF) + MEESSI scale, need of hospitalization and in-hospital all-cause mortality. The long-term outcomes analyzed were 90-day postdischarge adverse events and 90-day all-cause death. Associations between vaccination, HF decompensation severity and long-term outcomes were explored by unadjusted and adjusted logistic and Cox regressions by using 14 covariables that could act as potential confounders. RESULTS: Overall median (IQR) age was 84 (IQR = 77-89) years, and 56% were women. Vaccinated patients (n = 1139; 19%) were older, had more comorbidities and had worse baseline status, as assessed by New York Heart Association class and Barthel index, than did unvaccinated patients (n = 5008; 81%). Infection triggering decompensation was more common in vaccinated patients (50% vs 41%; P < 0.001). In vaccinated and unvaccinated patients, high or very-high risk decompensation was seen in 21.9% and 21.1%; hospitalization occurred in 72.5% and 73.7%; in-hospital mortality was 7.4% and 7.0%; 90-day postdischarge adverse events were 57.4% and 53.2%; and the 90-day mortality rate was 15.8% and 16.6%, respectively, with no significant differences between cohorts. After adjusting, vaccinated decompensated patients with HF had decreased odds for hospitalization (OR = 0.823, 95%CI = 0.709-0.955). CONCLUSION: In patients with HF, seasonal flu vaccination is associated with less severe decompensations.


Assuntos
Insuficiência Cardíaca , Humanos , Feminino , Idoso , Idoso de 80 Anos ou mais , Masculino , Insuficiência Cardíaca/epidemiologia , Alta do Paciente , Assistência ao Convalescente , Hospitalização , Vacinação
6.
Ecotoxicology ; 32(2): 166-187, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36689067

RESUMO

Aquatic ecosystems have been suffering deleterious effects due to the development of different economic activities. Metal(loid)s are one of the most persistent chemicals in environmental reservoirs, and may produce adverse effects on different organisms. Since fishes have been largely used in studies of metal(loid)s exposure, tilapia and largemouth bass were collected in three ecosystems from the Yaqui River Basin to measure the concentrations of metal(loid)s (chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), zinc (Zn) arsenic (As), mercury (Hg), and selenium (Se)) and some biomarkers (somatic indices, metallothionein expression and histopathological analysis) in tissues of both species. Metal(loid) concentrations varied seasonally among ecosystems in tissues of both species. The elements varied seasonally and spatially in tissues of both species, with a general distribution of liver > gills > gonads. Also, biomarkers showed variations indicative that the fish species were exposed to different environmental stressor conditions. The highest values of some biomarkers were in largemouth bass, possibly due to differences in their biological characteristics, mainly feeding habits. The multivariate analysis showed positive associations between metal(loid)s and biomarkers, which are usually associated to the use of these elements in metabolic and/or regulatory physiological processes. Both fish species presented histological damage at different levels, from SI types (changes that are reversible for organ structure) to SII types (changes that are more severe but may be repairable). Taken together, the results from this study suggest that the Yaqui River Basin is moderately impacted by metals and metalloids.


Assuntos
Bass , Ciclídeos , Mercúrio , Tilápia , Poluentes Químicos da Água , Animais , Bass/metabolismo , Ecossistema , Rios/química , México , Monitoramento Ambiental/métodos , Metais/metabolismo , Mercúrio/análise , Biomarcadores/metabolismo , Poluentes Químicos da Água/análise
7.
Front Neuroanat ; 17: 1305500, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38260117

RESUMO

Introduction: In primates, including humans, the centromedian/parafascicular (CM-Pf) complex is a key thalamic node of the basal ganglia system. Deep brain stimulation in CM-Pf has been applied for the treatment of motor disorders such as Parkinson's disease or Tourette syndrome. Rodents have become widely used models for the study of the cellular and genetic mechanisms of these and other motor disorders. However, the equivalence between the primate CM-Pf and the nucleus regarded as analogous in rodents (Parafascicular, Pf) remains unclear. Methods: Here, we analyzed the neurochemical architecture and carried out a brain-wide mapping of the input-output motifs in the mouse Pf at micropopulation level using anterograde and retrograde labeling methods. Specifically, we mapped and quantified the sources of cortical and subcortical input to different Pf subregions, and mapped and compared the distribution and terminal structure of their axons. Results: We found that projections to Pf arise predominantly (>75%) from the cerebral cortex, with an unusually strong (>45%) Layer 5b component, which is, in part, contralateral. The intermediate layers of the superior colliculus are the main subcortical input source to Pf. On its output side, Pf neuron axons predominantly innervate the striatum. In a sparser fashion, they innervate other basal ganglia nuclei, including the subthalamic nucleus (STN), and the cerebral cortex. Differences are evident between the lateral and medial portions of Pf, both in chemoarchitecture and in connectivity. Lateral Pf axons innervate territories of the striatum, STN and cortex involved in the sensorimotor control of different parts of the contralateral hemibody. In contrast, the mediodorsal portion of Pf innervates oculomotor-limbic territories in the above three structures. Discussion: Our data thus indicate that the mouse Pf consists of several neurochemically and connectively distinct domains whose global organization bears a marked similarity to that described in the primate CM-Pf complex.

8.
Horiz. sanitario (en linea) ; 21(2): 178-186, May.-Aug. 2022. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1448403

RESUMO

Abstract: Objective: To evaluate the effect of the ingestion of a fibrous extract of Stevia rebaudiana Bertoni stems on postprandial glycemia levels in healthy subjects. Materials and Methods: Cross-sectional, experimental research, carried out with ethical conditions of consent and reliability, in the Laboratory for the Evaluation of Nutritional Status of the Autonomous University of Carmen. For the clinical and anthropometric assessment of the participants, a medical history and body composition scan were used, respectively. The study population consisted of 16 healthy women with normal body mass indices (20-25 kg/m2). Instruments: a) Clinical-dietetic record and b) Biochemical data obtained from blood sampling obtained at different times. The data analysis was carried out with descriptive statistics. Results: The results shown in the group of participants in this study, it was observed that the mean value of the area under the curve (AUC) of glucose was 709.18 ± 23.60, while that of the fibrous extract of stevia stems was 556.59 ± 50.47. Conclusions: Stevia rebaudiana stems, due to their dietary fiber content, can be an alternative for the use and revaluation of sustained waste in the circular economy in the development of functional products, giving it an added value that contributes in some way to reducing overweight and obesity, with a hypoglycemic effect in patients with type 2 diabetes mellitus (DM).


Resumen: Objetivo: Evaluar el efecto de la ingesta de un extracto fibroso de tallos de Stevia rebaudiana Bertoni sobre los niveles de glicemia postprandial en sujetos sanos. Materiales y Métodos: Investigación transversal, experimental, realizada con condiciones éticas de consentimiento y confiabilidad, en el laboratorio de Evaluación del Estado Nutricional de la Universidad Autónoma del Carmen. Para la valoración clínica y antropométrica de los participantes se utilizó una historia clínica y escáner de composición corporal, respectivamente. La población de estudio fue conformada por 16 mujeres sanas con índices de masa corporal normales (20-25 kg/m2). Instrumentos: a) Expediente clínico-dietético y b) Datos bioquímicos obtenidos de la toma sanguínea obtenidos en los diferentes tiempos. Se realizó el análisis de los datos con estadística descriptiva. Resultados: Los resultados mostrados en el grupo de participantes en este estudio, se observó que el valor medio del área bajo la curva (AUC) de la glucosa fue de 709.18 ± 23.60, mientras que el del extracto fibroso de tallos de stevia fue de 556.59 ± 50.47. Conclusiones: Los tallos de Stevia rebaudiana Bertoni. por su contenido en fibra dietética, pueden ser una alternativa para el uso y revalorización de residuos sostenidos en la economía circular en el desarrollo de productos funcionales, otorgándole un valor agregado que contribuye de alguna manera a reducir el sobrepeso y la obesidad, con efecto hipoglucemiante en pacientes con diabetes mellitus (DM) tipo 2.

9.
Environ Monit Assess ; 194(7): 466, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35641703

RESUMO

Marine ecosystems are subject to contamination by metals and metalloids and other elements and compounds that are emitted due to various human activities. These substances subsequently induce changes in marine biota after entering the marine environment. Marine organisms are frequently consumed worldwide because they constitute relatively cheap and accessible food items of high nutrient quality. The aim of this study was to estimate metal accumulation in frequently consumed marine species and to evaluate the associated health risks for particular population groups in a coastal region of northwestern Mexico. The marine species were consumed in different quantities between spring (from 0.29 kg year-1 for white clam, to 38.40 kg year-1 for blue crab) and autumn (from 0.34 kg year-1 for white clam, to 15.02 kg year-1 for leopard grouper). The general distribution of metal concentrations in the marine species (n = 13 in each season) evaluated in this study followed the trend of Fe > Zn > Cu > Mn > Cr with the highest metal concentrations detected during autumn. Although many metal concentrations were above the international standards of the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO), the hazard quotient (HQ) and hazard index (HI) values for the women in this study indicated that their health was not at risk due to the consumption of either fish or seafood. In contrast, the HQ and HI values determined for groups of men and children indicated that they are at risk due to the frequent consumption of most species evaluated in this study.


Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água , Animais , Biota , Ecossistema , Feminino , Humanos , Metais/análise , México , Medição de Risco , Poluentes Químicos da Água/análise
10.
Rev. logop. foniatr. audiol. (Ed. impr.) ; 41(4): 214-214, Oct-Dic, 2021.
Artigo em Espanhol | IBECS | ID: ibc-227667

RESUMO

Introducción: Tanto el envejecimiento saludable como el Deterioro Cognitivo Leve (estado preclínico entre la salubridad cognitiva y la demencia) se postulan como dos estados diferentes no patológicos en el adulto mayor en los que encontramos alteraciones lingüísticas y comunicativas parecidas pero que requieren atención diferenciada, siendo la detección precoz de estas fundamental para la preservación comunicativa. Objetivos: Los objetivos planteados son analizar las alteraciones en lenguaje y comunicación en dichas poblaciones para establecer las diferencias más significativas y realizar un diagnóstico diferencial. Metodología: La metodología empleada ha sido hipotética-deductiva, con análisis cuantitativo y cualitativo. Resultados: Entre los resultados obtenidos se confirma la distinción en las alteraciones de ambas poblaciones, destacando el área pragmática como elemento más diferenciador. Conclusiones: Tras la investigación realizada se concluye la necesidad de realizar un diagnóstico diferencial en ambas poblaciones, para poder llevar a cabo la intervención logopédica más adecuada a cada población.(AU)


Assuntos
Humanos , Masculino , Feminino , Disfunção Cognitiva , Diagnóstico Diferencial , Envelhecimento , Idioma , Comunicação
11.
Preprint em Inglês | medRxiv | ID: ppmedrxiv-21265969

RESUMO

BackgroundIn Argentina, the burden of COVID-19 on health systems and physicians was substantial with difficulties on daily triage decisions which have to be made in the context of grave shortages of basic equipment and consumables. Purposethis study was performed to understand what physicians were experiencing during the COVID-19 pandemic in La Plata (capital city of Buenos Aires province, Argentina). MethodsA cross-sectional study was performed; a questionnaire was sent by e-mail to physicians who work in this city during November 2020. The questionnaire was made based on Medscape US and International Physicians COVID-19 Experience Report: Risk, Burnout, Loneliness. Statistical analysistest for normality was performed employing the Kolmogorov-Smirnov test while Chi-square test of independence to examine the relationship between sex and workplace with nominal variables. For categorical variables, Kendalls tau correlation was performed to test for independence. ANOVA was developed to examine differences between physicians age. Statistical significance was set to p < 0.05 in all cases. All statistical analysis was done employing SPSS Statistics, Version 24 (IBM, USA). Results203 physicians answered the questionnaire; the majority of physicians (96%) considered stressful their experience during pandemic and reported distress episodes being for more than 60% the most stressful of their practices, 30% presented depression and were medically treated, while 32.7% felt loneliness with 4 physicians with suicidal thoughts. ConclusionThe results highlight the need to protect the psychological well-being of the healthcare community, and to invest resources to significantly promote the mental health of professionals.

12.
iScience ; 24(5): 102494, 2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34113829

RESUMO

Dihydroorotate dehydrogenase (DHODH) is essential for the de novo synthesis of pyrimidine ribonucleotides, and as such, its inhibitors have been long used to treat autoimmune diseases and are in clinical trials for cancer and viral infections. Interestingly, DHODH is located in the inner mitochondrial membrane and contributes to provide ubiquinol to the respiratory chain. Thus, DHODH provides the link between nucleotide metabolism and mitochondrial function. Here we show that pharmacological inhibition of DHODH reduces mitochondrial respiration, promotes glycolysis, and enhances GLUT4 translocation to the cytoplasmic membrane and that by activating tumor suppressor p53, increases the expression of GDF15, a cytokine that reduces appetite and prolongs lifespan. In addition, similar to the antidiabetic drug metformin, we observed that in db/db mice, DHODH inhibitors elevate levels of circulating GDF15 and reduce food intake. Further analysis using this model for obesity-induced diabetes revealed that DHODH inhibitors delay pancreatic ß cell death and improve metabolic balance.

13.
Environ Sci Pollut Res Int ; 28(40): 56175-56187, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34050511

RESUMO

The biomagnification of Hg and Se was studied using nitrogen stable isotope analysis during four seasons in a coastal lagoon of the eastern central Gulf of California. This lagoon receives agricultural, municipal, and shrimp aquaculture effluents. The species were categorized into organism groups and presented a significant accumulation of Hg and Se with respect to the sources, while the concentration of both elements in sediment and suspended particulate matter (SPM) was low. Our data confirms the positive transfers (biomagnification factors >1) of Hg and Se in the entire studied food web, and it was structured in five trophic levels across all seasons. Additionally, there were no linear correlations between the molar Se:Hg ratios and the trophic levels of the organism groups. However, the Se:Hg ratios among organism groups were >1, which indicates that there is an excess of Se and that it is not a limiting factor for the detoxification of Hg.


Assuntos
Mercúrio , Selênio , Poluentes Químicos da Água , Agricultura , Animais , Aquicultura , Bioacumulação , Monitoramento Ambiental , Peixes , Cadeia Alimentar , Mercúrio/análise , Selênio/análise , Poluentes Químicos da Água/análise
14.
Circulation ; 143(8): 837-851, 2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33617315

RESUMO

More than 40 years after the 1978 Bethesda Conference on the Declining Mortality from Coronary Heart Disease provided the scientific community with a blueprint for systematic analysis to understand declining rates of coronary heart disease, there are indications the decline has ended or even reversed despite advances in our knowledge about the condition and treatment. Recent data show a more complex situation, with mortality rates for overall cardiovascular disease, including coronary heart disease and stroke, decelerating, whereas those for heart failure are increasing. To mark the 40th anniversary of the Bethesda Conference, the National Heart, Lung, and Blood Institute and the American Heart Association cosponsored the "Bending the Curve in Cardiovascular Disease Mortality: Bethesda + 40" symposium. The objective was to examine the immediate and long-term outcomes of the 1978 conference and understand the current environment. Symposium themes included trends and future projections in cardiovascular disease (in the United States and internationally), the evolving obesity and diabetes epidemics, and harnessing emerging and innovative opportunities to preserve and promote cardiovascular health and prevent cardiovascular disease. In addition, participant-led discussion explored the challenges and barriers in promoting cardiovascular health across the lifespan and established a potential framework for observational research and interventions that would begin in early childhood (or ideally in utero). This report summarizes the relevant research, policy, and practice opportunities discussed at the symposium.


Assuntos
Doenças Cardiovasculares/mortalidade , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/patologia , Congressos como Assunto , Doença das Coronárias/epidemiologia , Doença das Coronárias/mortalidade , Doença das Coronárias/patologia , Complicações do Diabetes/epidemiologia , Humanos , Morbidade/tendências , Obesidade/complicações , Obesidade/epidemiologia , Fatores de Risco , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/mortalidade , Acidente Vascular Cerebral/patologia , Taxa de Sobrevida/tendências , Estados Unidos/epidemiologia , Urbanização
15.
Environ Sci Pollut Res Int ; 28(13): 16895-16912, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33398728

RESUMO

Water reservoirs are essential for regional economic development, as populations depend on them for agriculture irrigation, flood control, hydroelectric power generation, water supply for human consumption, and subsistence fishing activities. However, the reservoir environmental quality can be disturbed by enhanced sediment input and trace metal contamination, affecting human health as a consequence of contaminated water and fish consumption. With the purpose to understand the trends and extent of sediment accumulation and trace element contamination in the Oviachic reservoir (OV, northwestern Mexico) since its construction, the temporal variations of sediment accumulation, and As, Cr, Cu, Hg, Ni, Pb, and Zn concentrations, enrichment, and fluxes, were evaluated through the study of two 210Pb-dated sediment cores. We assumed that siltation and trace element contamination were driven by the development of anthropogenic activities in the region within the past ~ 70 years. Elemental concentrations accounted from null to minor enrichment for most elements, but moderate to significant enrichment by Hg. Mercury, As, and Cu fluxes have notably increased since the past decade, most likely because of a combination of anthropogenic and natural processes, including catchment erosion, artisanal gold mining, and recent drought conditions in the region. Arsenic and Hg concentrations may pose deleterious risks to biota in the reservoir, and consequently to humans through fish consumption, for which further biological and toxicological tests are advisable. This study highlights the importance of using sediment dating to assess historical trends of metal contamination and identify possible sources, to support decision-making in programs addressed to reduce environmental and health risks in aquatic ecosystems.


Assuntos
Metais Pesados , Oligoelementos , Poluentes Químicos da Água , Animais , Ecossistema , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Metais Pesados/análise , México , Oligoelementos/análise , Água , Poluentes Químicos da Água/análise
16.
Biol Trace Elem Res ; 199(8): 3112-3125, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33058041

RESUMO

In the present paper, we investigated the accumulation of six metals in tilapia (Oreochromis nilocticus) and largemouth bass (Micropterus salmoides) as indicators of the environmental pollution present at three constructed dams in the Yaqui River basin in Sonora, Mexico. The La Angostura (ANG), El Cajon de Onapa (ECO), and El Oviachic (OVI) dams are ecosystems under different degrees of anthropogenic stress. The collected fishes were dissected to obtain liver, gonad, stomach, gill, and muscle samples to determine the metal concentrations of Fe, Mn, Ni, Cu, Zn, and Cr. The results of a PERMANOVA showed that the concentrations of Fe, Cu, and Zn were significantly higher in tilapia liver, stomach, and gill tissues compared with those of the largemouth bass. Also, differences were detected between seasons, with the metal concentrations during the dry season being significantly higher than those of the rainy season (p < 0.001). The results of a principal component analysis showed an association between metals, tissues, and dams with significantly higher (p < 0.001) concentrations in tilapia from the ECO dam compared with those from the ANG and OVI dams. The general distribution of metals in the tissues was as follows: liver > stomach-gills > gonads > muscle. Variations in metal concentrations may be indicative of the different sources of anthropogenic stress in each ecosystem.


Assuntos
Bass , Metais Pesados , Tilápia , Poluentes Químicos da Água , Animais , Bioacumulação , Ecossistema , Monitoramento Ambiental , Metais Pesados/análise , México , Rios , Poluentes Químicos da Água/análise
17.
Insects ; 11(6)2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32575885

RESUMO

Every year, Danaus plexippus (Linnaeus, 1758) travels to hibernate in oyamel fir forests located between the limits of the states of Michoacán and Mexico in Mexico. Climate change and anthropogenic actions are diminishing oyamel fir forests in Mexico, putting pressure on the habitats of monarch butterflies. In the last decade, new colonies outside their usual range have been predicted through modeling and reported by the National Commission on Protected Areas of Mexico. The objectives of the study were to recover information on the historical and new hibernation sites, reported or modeled, from different literature sources. We also aimed to perform a bioclimatic and forest biometric characterization of new monarch butterfly colonies located in Sierra Nevada in Mexico to provide information to aid in conservation strategies for the monarch butterfly population. We conducted field trips to georeference the colonies at sites located in the Atlautla municipality in Mexico State. Climatic, topographic, and forest biometric variables were used to characterize the sites physically. It was found that the butterfly's roosts occurred at a higher elevation than those recorded by other sources. The locations where the monarch's colonies were established, in the east of Mexico State, provide information relevant to defining and developing policies for their conservation.

19.
Environ Sci Pollut Res Int ; 27(14): 16774-16783, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32133613

RESUMO

Mercury and selenium were assessed in Mustelus henlei, which is a carnivorous predatory shark that is important for the coastal communities of the northern Mexican Pacific (NMP). Sixty-two individuals were sampled; muscle and liver were isolated and analyzed by atomic absorption spectrophotometry. The mean Hg concentrations (wet weight) obtained for muscle (0.08 ± 0.10 µg g-1) and liver (0.09 ± 0.26 µg g-1) were below the allowed limits (< 1.0 µg g-1 Hg). The average Se concentration was 0.03 ± 0.01 µg g-1 in muscle and 0.13 ± 0.05 µg g-1 in liver. The Se/Hg molar ratio of muscle was 1.83; however, the selenium health benefit value (HBVSe) was of 0.08. We calculated that an adult man (70 kg), an adult woman (60 kg), and a child (16 kg) could consume 1595, 838, and 223 g/week of M. henlei muscle, respectively, without risks to health. In conclusion, the concentrations and molar ratio of Hg and Se in M. henlei muscle mean that consumption of this shark's meat does not represent neither a benefit nor a public health risk.


Assuntos
Mercúrio/análise , Selênio/análise , Tubarões , Poluentes Químicos da Água/análise , Animais , Criança , Monitoramento Ambiental , Feminino , Humanos , Masculino , México
20.
PLoS One ; 15(2): e0229378, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32101589

RESUMO

A series of 3D obstacle limitation surfaces (OLS) define the limits to which objects may project in the airspace in order to configure the airspace around aerodromes that must be kept free from obstacles. The aim is to ensure that aircraft can safely carry out their scheduled operations, and to prevent the aerodromes from becoming unusable due to the proliferation of obstacles in the surrounding area. One such possible obstacle is the vegetation growing in the zone. This work consists of a study of the variation in the vegetation in the El Prat airport (Barcelona-El Prat Josep Tarradellas) and the surrounding area in the years 2011-2018, and of the way in which it has influenced the configuration of the OLS. Until 2010, obstacle studies were carried out every four years but the growth of plant obstacles during this period was not controlled. Although the rate of tree growth depends on several factors such as age, species, site quality and forestry treatment, the parameter analysed in this research is height, as this is what will interfere in the OLS. This study therefore focuses on measuring the height and geolocation of the obstacle in order to determine its influence on the OLS, and on determining the subsequent actions, if any, that need to be taken in regard to this vegetation element to avoid it becoming a risk to operational safety. As a result, the growth and vulnerability of 84 vegetation obstacles from 794 terrain elements have been detected. The result of this study is the design, using geographic information systems, of a tool to assist airport managers in the automated control and monitoring of the vegetation in the obstacle limitation surfaces to avoid compromising the safety of airport operations and mitigating environmental impacts.


Assuntos
Aeroportos , Produtos Agrícolas/crescimento & desenvolvimento , Monitoramento Ambiental/métodos , Sistemas de Informação Geográfica , Medição de Risco/métodos , Tecnologia da Informação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...