1,173 research outputs found
Excess portal venous long-chain fatty acids induce syndrome X via HPA axis and sympathetic activation
We tested the hypothesis that excessive portal venous supply of long-chain fatty acids to the liver contributes to the development of insulin resistance via activation of the hypothalamus-pituitary-adrenal axis (HPA axis) and sympathetic system. Rats received an intraportal infusion of the long-chain fatty acid oleate (150 nmol/min, 24 h), the medium-chain fatty acid caprylate, or the solvent. Corticosterone (Cort) and norepinephrine (NE) were measured as indexes for HPA axis and sympathetic activity, respectively. Insulin sensitivity was assessed by means of an intravenous glucose tolerance test (IVGTT). Oleate infusion induced increases in plasma Cort (Δ = 13.5 ± 3.6 µg/dl; P < 0.05) and NE (Δ = 235 ± 76 ng/l; P < 0.05), whereas caprylate and solvent had no effect. The area under the insulin response curve to the IVGTT was larger in the oleate-treated group than in the caprylate and solvent groups (area = 220 ± 35 vs. 112 ± 13 and 106 ± 8, respectively, P < 0.05). The area under the glucose response curves was comparable [area = 121 ± 13 (oleate) vs. 135 ± 20 (caprylate) and 96 ± 11 (solvent)]. The results are consistent with the concept that increased portal free fatty acid is involved in the induction of visceral obesity-related insulin resistance via activation of the HPA axis and sympathetic system.
Monitoring the salt marsh vegetation and flora of the Baixo Vouga Lagunar (Ria of Aveiro, Portugal)
El carácter transicional de la Ría de Aveiro le confiere una riqueza florística singular, integrando comunidades vegetales típicas de las
regiones Eurosiberiana y Mediterránea. La implantación del Proyecto Desenvolvimento Agrícola do Vouga (PDAV) va a provocar una
modificación de las tasas de encharcamiento y una reducción gradual de la salinidad, factores ecológicos determinantes para muchas de las
comunidades halófilas y helofíticas. El presente trabajo pretende contribuir a un mejor conocimiento de la tipología de la vegetación local, que
sirva como base para desarrollar un programa de monitorización adecuado que detecte las alteraciones en los patrones espacio- temporales
de la vegetación de los sistemas húmedos. Teniendo como objetivo seleccionar los puntos de muestreo donde instalar las parcelas
permanentes de monitorización, se realizó una caracterización de la flora y la vegetación a través de trece transectos utilizando una
aproximación simplificada al método de Braun- Blanquet. Una vez identificados los tipos de vegetación - en función de su composición
florística, corología y ecología - fueron seleccionados al azar inventarios representativos de cada tipo, en los que han sido instaladas dichas
parcelas.The transitional
biogeographic character of the Ria de Aveiro lagoon area confers it a singular floristic richness, integrating plant communities typical for the
Eurosiberian as well as Mediterranean Region. The implementation of the Agricultural Development Plan of the Lower Vouga area (PDAV) in
the near future is expected to result in noticeable changes in the tidal submersion regime and a gradual reduction of salinity levels, which are
determining ecological factors for many of the halophytic and helophytic plant communities. The present work pretends to contribute to a
better knowledge of the local vegetation types and, thereby, to the implementation of an adequate monitoring programme for detecting
changes in the spatio-temporal vegetation patterns of the wetlands. With the objective to select the locations for the installation of permanent
quadrats, the vegetation of the wetlands was described along 13 transects using a simplified Braun-Blanquet approach. A total of 24 local
vegetation types were recognised, 23 of which were selected for the current monitoring programme
Перспективи використання теорії катастроф у дослідженні економічних криз
OBJECTIVE: To assess in-hospital and long-term mortality of Dutch ICU patients admitted with an acute intoxication. DESIGN: Cohort of ICU admissions from a national ICU registry linked to records from an insurance claims database. SETTING: Eighty-one ICUs (85% of all Dutch ICUs). PATIENTS: Seven thousand three hundred thirty-one admissions between January 1, 2008, and October 1, 2011. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Kaplan-Meier curves were used to compare the unadjusted mortality of the total intoxicated population and for specific intoxication subgroups based on the Acute Physiology and Chronic Health Evaluation IV reasons for admission: 1) alcohol(s), 2) analgesics, 3) antidepressants, 4) street drugs, 5) sedatives, 6) poisoning (carbon monoxide, arsenic, or cyanide), 7) other toxins, and 8) combinations. The case-mix adjusted mortality was assessed by the odds ratio adjusted for age, gender, severity of illness, intubation status, recurrent intoxication, and several comorbidities. The ICU mortality was 1.2%, and the in-hospital mortality was 2.1%. The mortality 1, 3, 6, 12, and 24 months after ICU admission was 2.8%, 4.1%, 5.2%, 6.5%, and 9.3%, respectively. Street drugs had the highest mortality 2 years after ICU admission (12.3%); a combination of different intoxications had the lowest (6.3%). The adjusted observed mortality showed that intoxications with street drugs and "other toxins" have a significant higher mortality 1 month after ICU admission (odds ratio adj = 1.63 and odds ratioadj= 1.73, respectively). Intoxications with alcohol or antidepressants have a significant lower mortality 1 month after ICU admission (odds ratioadj = 0.50 and odds ratioadj = 0.46, respectively). These differences were not found in the adjusted mortality 3 months upward of ICU admission. CONCLUSIONS: Overall, the mortality 2 years after ICU admission is relatively low compared with other ICU admissions. The first 3 months after ICU admission there is a difference in mortality between the subgroups, not thereafter. Still, the difference between the in-hospital mortality and the mortality after 2 years is substantial
Effectiveness of hydromulching to reduce runoff and erosion in a recently burnt pine plantation in central Portugal
Forest fires can greatly increase runoff and surface erosion rates. Post‐fire soil erosion control measures are intended to minimize this response and facilitate ecosystem recovery. In a few recent cases, hydromulch has been applied, and this consists of a mixture of organic fibers, water and seeds. The objectives of this research were to (i) analyze the effectiveness of hydromulch in reducing post‐fire runoff and sediment production and (ii) determine the underlying processes and mechanisms that control post‐fire runoff and erosion. After a wildfire occurred in August 2008, 14 plots ranging in size from 0·25 to 10 m2 were installed on a 25 degree slope in a burnt pine plantation that had also been subjected to salvage logging. Half of the plots were randomly selected and treated with hydromulch. One of two slope strips adjacent to the plots was also hydromulched and used for monitoring some soil properties. Measurements made in each of the first 3 years following the wildfire included (i) the plot‐scale runoff volumes and sediment yields; (ii) soil shear strength, soil moisture, and soil water repellency; and (iii) surface cover. The hydromulch reduced overland flow volume by 70% and soil erosion by 83%. The decrease in runoff was attributed to the increase in soil water retention capacity and the decrease in soil water repellency, whereas the reduction in soil erosion was initially attributed to the protective cover provided by the hydromulch and lately to an enhanced vegetative regrowth in the third year after burning.publishe
Two-stage model-based design of cancer phase I dose escalation trials: evaluation using the phase I program of barasertib (AZD1152)
Introduction Modeling and simulation of pharmacokinetics and pharmacodynamics has previously been shown to be potentially useful in designing Phase I programs of novel anti-cancer agents that show hematological toxicity. In this analysis, a two-stage model-based trial design was evaluated retrospectively using data from the Phase I program with the aurora kinase inhibitor barasertib. Methods Data from two Phase I trials and four regimens were used (n = 79). Using barasertib-hydroxy QPA plasma concentrations and neutrophil count data from only study 1A, a PKPD model was developed and subsequently used to predict the MTD and a safe starting dose for the other trials. Results The PKPD model based on data from the first study adequately described the time course of neutrophil count fluctuation. The two-stage model-based design provided safe starting doses for subsequent phase I trials for barasertib. Predicted safe starting dose levels were higher than those used in two subsequent trials, but lower than used in the other trial. Discussion The two-stage approach could have been applied safely to define starting doses for alternative dosing strategies with barasertib. The limited improvement in efficiency for the phase I program of barasertib may have been due to the fact that starting doses for the studied phase I trials were already nearly optimal. Conclusion Application of the two-stage model-based trial design in Phase I programs with novel anti-cancer drugs that cause haematological toxicity is feasible, safe, and may lead to a reduction in the number of patient treated at sub-therapeutic dose-levels
Post-fire management and biocrust development interact in mid-term soil recovery after a wildfire
Understanding the role of biocrust-forming mosses in soil recovery after wildfires is necessary for assessing the resilience of managed ecosystems. The purpose of this study was to investigate the mid-term impacts of two contrasting post-fire management strategies on soil recovery in eucalypt plantations in north-central Portugal, where a high cover of biocrust-forming mosses developed post-fire, contributing to erosion control. Six years after a wildfire, we examined the legacy effects of salvage logging and two rates of mulch application using logging residues (a standard rate of 8.0 Mg ha-1 and a reduced rate of 2.6 Mg ha-1 ) on soil properties, and explored the interaction between moss biocrusts and forest management practices on soils. Our findings reveal the resilience of soils to physical disturbance after logging operations, with no persistent negative effects on their physicochemical properties. Although forest residue mulches showed minimal influence on soils after six years, an interesting interaction with moss biocrusts was observed. In the absence of moss cover, direct contact of wood residues with soil at the standard mulch rate promoted higher nutrient content and biochemical activity, potentially attributed to accelerated decomposition processes. Regardless of the management applied, our study highlights the role of moss biocrusts in improving soil aggregation and biochemical processes in the mid-term. However, the severe water repellency observed in these soils may have impeded further biocrust expansion. Understanding the implications of forest management practices on soil recovery after wildfires is imperative for guiding strategies aimed at promoting ecosystem recovery and resilience in fire-prone managed forest ecosystems
Splash Erosion on Terraces, Does It Make a Difference If the Terracing Is Done before or after a Fire?
This article belongs to the Section Soil and Hydrology[EN] Terraces are a common Mediterranean feature influencing soils, slopes and subsurface hydrology; however, little is known about their impact on erosion processes, especially in humid regions. The purpose of this study was to assess how terracing after a fire affected erosion processes such as splash erosion. For 8 months, the study monitored splash erosion in three terraced plots, one plot under pre-fire conditions and the other two under post-fire conditions. Assessment of the impact of the terracing treatment in such plots was carried out by the installation of two different splash erosion quantitative systems: cups and funnels. An analysis of the splash data obtained in 17 rainfall events and meteorological data collected during each one of those periods was then performed. A significant positive correlation between the amount of rainfall and the splash erosion was observed. The two splash sampling systems show a high degree of concordance; however, the funnel-type model seems to be the most appropriate when it comes to preventing loss of splashed soil samples. The post-fire treatment with terracing leads to a smaller stability of surface soil aggregates, causing higher splash erosion rates. Sampling using the funnel system collects three times the amount of splashed soil than that collected by the cup system, although both systems correlate appropriately with the meteorological parametersSIThis study has been supported by the projects EROSFIRE (POCTI/AGR/60354/2004) and EROSFIRE-II (PTDC/AGR-CFL/70968/2006), funded by the Portuguese Foundation for Science and Technology (FCT) with co-funding by FEDER through the POCI2010 Program. The Junta de Castilla y León has also contributed to this Project with Grant LE014A07, and the Spanish Ministry of Education with Grant TEC2007-63216. This research was also funded partially by project PID2020-120439RA-I00 financed by MCIN/AEI/10.13039/50110001103
Potential Impact of Climate Change on Suspended Sediment Yield in NW Spain: A Case Study on the Corbeira Catchment
[Abstract] Soil losses and the subsequent sediment delivery constitute significant environmental threats. Climate change is likely to have an impact on the availability of water and therefore on sediment yield in catchments. In this context, quantifying the sediment response to an increased atmospheric CO2 concentration and climate change is of utmost importance to the proper management of rural catchments. However, quantitative assessment of climate change impact remains a complex task. In this study, the potential medium (2031–2060) and long-term (2069–2098) impacts of projected changes of temperature, rainfall and CO2 concentration on sediment yield in a small rural catchment located in NW Spain were evaluated using the Soil and Water Assessment Tool (SWAT) model. Climate change scenarios were created using future climate data projected by regional climate models from the ENSEMBLES project and two CO2 concentration scenarios (550 and 660 ppm). The results showed that climate change would have a noticeable impact on suspended sediment if the forecast temperature, rainfall and CO2 concentration changes included in this study were met. Overall, suspended sediment is expected to decrease (2031–2060: −11%, 2069–2098: −8%) compared to the baseline period (1981–2010), mainly due to decreased streamflow. However, an increase in sediment transport in winter is predicted, possibly associated with increased erosion in cultivated areas (11%–17%), suggesting that, at this time of the year, the effect of soil detachment prevails over sediment transport capacity. Consequently, management practices aimed at reducing soil erosion in cultivated areas should be carried out, because these are the main source of sediment in the study area.Galicia. Consellería de Economía e Industria; 10MDS103031Ministerio de Economía y Competitividad; CGL2014-56907-
Wildfire impacts on freshwater detrital food webs depend on runoff load, exposure time and burnt forest type
In the last decades, land-use changes have made Mediterranean forests highly susceptible to wildfires, which can cause several impacts not only on burnt areas, but also on adjacent aquatic ecosystems. Post-fire runoff from burnt areas may transport toxic substances to streams by surface runoff, including polycyclic aromatic hydrocarbons (PAHs) and metals, which can be noxious to aquatic organisms. Impacts on aquatic ecosystems can be related to fire severity, forest type and the exposure period; however, these factors have not been investigated in tandem. Here, we used the stream detrital system to determine the impacts of post-fire runoffs and stream water from a burnt catchment on trophic interactions between stream microbial communities and invertebrate shredders involved in leaf litter decomposition. Three distinct types of samples were collected from a burnt catchment: post-fire runoffs from high severity wildfires in Pinus and Eucalyptus forests, and stream water. Microbial decomposer communities (fungi and bacteria) and the invertebrate shredder Allogamus ligonifer were exposed for 10 and 20 days to increasing concentrations (0, 50, 75 and 100%) of runoff extracts. Our results showed that post-fire runoffs from high severity wildfires reduced microbially-driven leaf litter decomposition (up to 79%), invertebrate feeding (up to 75%), fungal biomass (up to 39%) and altered community composition; effects were more severe at the longer exposure time. The impacts varied with the runoff source and were related to the chemical composition in metals and total PAHs. This study emphasizes the importance of assessing the indirect effects of wildfires taking into account the effects of the runoff source, load and exposure time on freshwater biota and their ecological functions. Therefore, best forest management practices should be applied to minimize post-fire runoffs reaching aquatic ecosystems and to reduce the effects of these extreme events on freshwater biodiversity and ecosystem functioning.This work was supported by the strategic programmes UID/BIA/04050/2019 (POCI-01-0145-FEDER-007569), UID/AMB/50017 (POCI-01–0145-FEDER-007638) and (UID/AMB/50017/2019), funded by national funds through the Portuguese Foundation For Science and Technology (FCT) I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI). FEDER-POFC-POCI-COMPETE and FCT supported this work (PIDDAC - PEst-OE/BIA/UI4050/2014, PTDC/AAG-GLO/4176/2012, POCI-01-0145-FEDER-028936, SFRH/BD/119957/2016 and PTDC/CTA-AMB/28936/2017)
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