4,760 research outputs found
Tendencias y respuestas de la fenología de la superficie terrestre a la variabilidad climática en la Pampa Argentina
Comprender la interacción entre los procesos de la superficie terrestre y la atmósfera es fundamental para predecir los efectos del cambio climático futuro sobre el funcionamiento de los ecosistemas y la dinámica del carbono. Los objetivos de este trabajo fueron analizar las tendencias en métricas de la fenología de la superficie terrestre derivadas de sensores remotos, y revelar su relación con la precipitación y el fenómeno ENSO en la región pampeana de Argentina. A partir de una serie temporal de imágenes del Índice de Vegetación de Diferencia Normalizada (NDVI) de MODIS para el período 2000-2014, se obtuvo para la región pampeana de Argentina el inicio de la estación de crecimiento (SOS), la integral anual del NDVI (i-NDVI, estimador lineal de la productividad anual), el tiempo del máximo anual del NDVI (t-MAX) y el rango relativo anual de NDVI (RREL, estimador de la estacionalidad). Posteriormente, se analizaron las relaciones espaciales y temporales con el Índice Multivariado del ENSO (MEI) y la precipitación. Los resultados mostraron una tendencia negativa en la productividad anual en un 53,6% del área de estudio asociado a zonas de pastizales naturales y semi-naturales, mientras que un 40,3% de la Pampa Argentina mostró una tendencia positiva significativa en la estacionalidad de las ganancias de carbono. Este estudio también revela que la variabilidad climática tiene un impacto significativo en la fenología de la superficie terrestre de la región pampeana, aunque este impacto es heterogéneo. SOS y t-MAX mostraron una correlación negativa significativa con la precipitación, lo que indica una ocurrencia más temprana. El 23,6% y 28,4% del área de estudio mostró una correlación positiva de la productividad anual con el MEI y la precipitación, respectivamente, asociado a pastizales (en el primer caso) y sobre pastizales y áreas agrícolas en el segundo caso. La variabilidad climática no explicó la variabilidad en la estacionalidad de la fenología. Las relaciones encontradas entre las métricas de la fenología de la superficie terrestre y la variabilidad climática podrían ser importantes para la implementación de estrategias para el manejo de los recursos naturales.Understanding the interaction between land surface and atmosphere processes is fundamental for predicting the effects of future climate change on ecosystem functioning and carbon dynamics. The objectives of this work were to analyze the trends in land surface phenology (LSP) metrics from remote sensing data, and to reveal their relationship with precipitation and ENSO phenomenon in the Argentina Pampas. Using a time series of MODIS Normalized Difference Vegetation Index (NDVI) data from 2000 to 2014, the start of the growing season (SOS), the annual integral of NDVI (i-NDVI, linear estimator of annual productivity), the timing of the annual maximum NDVI (t-MAX) and the annual relative range of NDVI (RREL, estimator of seasonality) were obtained for the Argentina Pampas. Then, spatial and temporal relationships with the Multivariate ENSO Index (MEI) and precipitation were analyzed. Results showed a negative trend in annual productivity over a 53.6% of the study area associated to natural and semi-natural grassland under cattle grazing, whereas a 40.3% of Argentina Pampas showed a significant positive trend in seasonality of carbon gains. The study also reveals that climate variability has a significant impact on land surface phenology in Argentina Pampas, although the impact is heterogeneous. SOS and t-MAX showed a significant negative correlation with the precipitation indicating an earlier occurrence. 23.6% and 28.4% of the study area showed a positive correlation of the annual productivity with MEI and precipitation, respectively, associated to rangelands (in the first case) and to both rangeland and croplands, in the second case. Climate variability did not explain the seasonal variability of phenology. The relationships found between LSP metrics and climate variability could be important for implementation of strategies for natural resource management.Fil: Lara, Bruno Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomía. Departamento Ciencias Básicas Agronómicas y Biológicas. Laboratorio de Investigación y Servicios en Teledetección de Azul; ArgentinaFil: Gandini, M.. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomía. Departamento Ciencias Básicas Agronómicas y Biológicas. Laboratorio de Investigación y Servicios en Teledetección de Azul; ArgentinaFil: Gantes, P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Universidad Nacional de Luján. Instituto de Ecología y Desarrollo Sustentable; ArgentinaFil: Matteucci, Silvia Diana. Universidad de Buenos Aires. Facultad de Arquitectura y Urbanismo. Grupo de Ecología del Paisaje y Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Glucose Transporter 9 (GLUT9) Plays an Important Role in the Placental Uric Acid Transport System.
BACKGROUND
Hyperuricemia is a common laboratory finding in pregnant women compromised by preeclampsia. A growing body of evidence suggests that uric acid is involved in the pathogenesis of preeclampsia. Glucose transporter 9 (GLUT9) is a high-capacity uric acid transporter. The aim of this study was to investigate the placental uric acid transport system, and to identify the (sub-) cellular localization of GLUT9.
METHODS
Specific antibodies against GLUT9a and GLUT9b isoforms were raised, and human villous (placental) tissue was immunohistochemically stained. A systemic GLUT9 knockout (G9KO) mouse model was used to assess the placental uric acid transport capacity by measurements of uric acid serum levels in the fetal and maternal circulation.
RESULTS
GLUT9a and GLUT9b co-localized with the villous (apical) membrane, but not with the basal membrane, of the syncytiotrophoblast. Fetal and maternal uric acid serum levels were closely correlated. G9KO fetuses showed substantially higher uric acid serum concentrations than their mothers.
CONCLUSIONS
These findings demonstrate that the placenta efficiently maintains uric acid homeostasis, and that GLUT9 plays a key role in the placental uric acid transport system, at least in this murine model. Further studies investigating the role of the placental uric acid transport system in preeclampsia are eagerly needed
Original Article
There is disagreement in the literature as to whether episodic memory maintains an inherent temporal organisation, that is, whether learned items are necessarily organised along some temporal dimension or whether temporal organisation is a task-specific occurrence. The current series of experiments explored this issue. In Experiment 1, we tested whether temporal or spatial contiguity was present in an incidental encoding task where either strategy (but not both together) could be employed at test. In Experiment 2, we attempted to facilitate the use of a spatial retrieval strategy at test by asking participants to recall the location where target items had been displayed at study, after incidental encoding. Experiment 3 explored the role of study-test congruency by informing participants at encoding that they would be tested on either their memory for the temporal sequence or spatial locations, and then testing both at retrieval. Finally, Experiment 4 employed a masking task at encoding to ensure participants could not predict the true nature of the task, despite it being incidental, and a surprise free recall task. Predominantly, participants displayed recall performance consistent with temporal contiguity, although there was evidence for spatial contiguity under certain conditions. These results are consistent with the notion that episodic memory has a stable and predictable temporal organisation
Time is of the essence: Exploring temporal and spatial organisation in episodic memory
There is disagreement in the literature as to whether episodic memory maintains an inherent temporal organisation, that is, whether learned items are necessarily organised along some temporal dimension or whether temporal organisation is a task-specific occurrence. The current series of experiments explored this issue. In Experiment 1, we tested whether temporal or spatial contiguity was present in an incidental encoding task where either strategy (but not both together) could be employed at test. In Experiment 2, we attempted to facilitate the use of a spatial retrieval strategy at test by asking participants to recall the location where target items had been displayed at study, after incidental encoding. Experiment 3 explored the role of study-test congruency by informing participants at encoding that they would be tested on either their memory for the temporal sequence or spatial locations, and then testing both at retrieval. Finally, Experiment 4 employed a masking task at encoding to ensure participants could not predict the true nature of the task, despite it being incidental, and a surprise free recall task. Predominantly, participants displayed recall performance consistent with temporal contiguity, although there was evidence for spatial contiguity under certain conditions. These results are consistent with the notion that episodic memory has a stable and predictable temporal organisation
Assessment of paracetamol toxic effects under varying seawater pH conditions on the marine polychaete hediste diversicolor using biochemical endpoints
Increasing atmospheric carbon dioxide (CO2) levels are likely to lower ocean pH values, after its dissolution in seawater. Additionally, pharmaceuticals drugs are environmental stressors due to their intrinsic properties and worldwide occurrence. It is thus of the utmost importance to assess the combined effects of pH decreases and pharmaceutical contamination, considering that their absorption (and effects) are likely to be strongly affected by changes in oceanic pH. To attain this goal, individuals of the marine polychaete Hediste diversicolor were exposed to distinct pH levels (8.2, 7.9, and 7.6) and environmentally relevant concentrations of the acidic drug paracetamol (PAR: 0, 30, 60, and 120 µg/L). Biomarkers such as catalase (CAT), glutathione S-transferases (GSTs), acetylcholinesterase (AChE), and cyclooxygenase (COX) activities, as well as peroxidative damage (through thiobarbituric acid reactive substance (TBARS) quantification), were quantified to serve as ecotoxicological endpoints. Data showed a general increase in CAT and a decrease in GST activities (with significant fluctuations according to the tested conditions of PAR and pH). These changes are likely to be associated with alterations of the redox cycle driven by PAR exposure. In addition, pH levels seemed to condition the toxicity caused by PAR, suggesting that the toxic effects of this drug were in some cases enhanced by more acidic conditions. An inhibition of AChE was observed in animals exposed to the highest concentration of PAR, regardless of the pH value. Moreover, no lipid peroxidation was observed in most individuals, although a significant increase in TBARS levels was observed for polychaetes exposed to the lowest pH. Finally, no alterations of COX activities were recorded on polychaetes exposed to PAR, regardless of the pH level. The obtained results suggest that seawater acidification is detrimental to marine wildlife, since it may enhance toxic effects caused by environmental realistic concentrations of acidic drugs, such as PAR. This work was crucial to evidence that ocean acidification, in the context of a global change scenario of increased levels of both atmospheric and oceanic CO2, is a key factor in understanding the putative enhanced toxicity of most pharmaceutical drugs that are of an acidic nature.info:eu-repo/semantics/publishedVersio
Nutritional Status among Portuguese and Turkish Older Adults Living in the Community: Relationships with Sociodemographic, Health and Anthropometric Characteristics
Malnutrition is widespread among older adults, and its determinants may differ between countries. We compared Portuguese and Turkish non-institutionalized older adults regarding nutritional status, sociodemographic, health and anthropometric characteristics and studied the relationships between nutritional status and those characteristics. This cross-sectional study analyzed data from 430 Portuguese and 162 Turkish non-institutionalized older adults regarding sociodemographics, health conditions, the Mini-Nutritional Assessment (MNA-FF) and anthropometry. Turkish older adults were more likely to be malnourished or at risk of malnutrition and had lower average BMI but a higher calf circumference. A higher proportion of the Portuguese sample had tooth loss, diabetes, hypertension, oncologic diseases, kidney diseases, osteoarticular problems or eye problems, while less had anemia. A better nutritional status (higher MNA-FF score) was found among the Portuguese, males, people using dentures, those without tooth loss, hypertension, cardiovascular diseases, anemia or oncological diseases and was related to younger age, higher BMI and a higher calf circumference. Malnutrition and its risk were higher among older adults from Turkey, despite Portuguese older adults presenting a higher prevalence of chronic diseases. Being female, older age, tooth loss, hypertension, anemia, CVD or oncological disorders and having a lower BMI or CC were associated with higher rates of malnutrition among older adults from Portugal and Turkey
A Systematic Review and Meta-analysis
Funding Information: This research was funded through the Portuguese Foundation for Science and Technology (FCT), I.P., under Project UIDB04045/2020. Publisher Copyright: © 2022, The Author(s).Background: Physical activity is essential in acquiring healthy lifestyle behaviors in the early years of maturational development and preventing various diseases. Resistance training (RT) is fundamental for improving body composition and is increasingly recommended for obese adolescents. A systematic review and meta-analysis were performed to synthesize and analyze data on the effects of RT programs in this population, seeking to develop useful recommendations for health and sports professionals. Methods: A search was performed using four databases (Web of Science, Scopus, PubMed, and ScienceDirect). According to specific inclusion criteria, twenty-one studies were selected to evaluate the impact of RT on body mass index (BMI), body fat, waist circumference, muscle strength, insulin sensitivity, lean mass and cardiorespiratory fitness. Results: After the RT programs, the adolescents improved their muscle strength (SMD, 1.44; 95% CI: 0.76–2.12), cardiorespiratory fitness (SMD, 1.09; 95% CI: 0.15–2.04), BMI (SMD, 0.21; 95% CI: 0.07–0.35), waist circumference (SMD, 0.27; 95% CI: 0.06–0.47) and body fat (SMD, 0.20; 95% CI: 0.05–0.34). However, insulin sensitivity (SMD, 0.32; 95% CI: − 0.47 to 1.10) and lean mass (SMD, 0.12; 95% CI: − 0.06 to 0.31) did not reveal any changes. Different RT programs were used but it seems that 2–3 times/week ∼60 min/session of RT for 12 weeks should be recommended for positive changes. Conclusions: RT seems to be effective when the objective is to improve muscle strength, cardiorespiratory fitness and can be an efficient strategy to reduce obesity in adolescents by reducing body fat, waist circumference and body mass index. PROSPERO Registration number: CRD42022333411.publishersversionpublishe
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