ALBERT

Description: The erythrocytes of mammals represent a good model to evaluate the cytotoxicity of molecules, organic and inorganic, natural or synthetic, by cellular damage measure. Indeed, before any investigation on the mechanism of action of different molecules, it is important to perform a cytotoxicity assay. Among the different cytotoxicity assays that assess a possible toxicity in the red blood cells is the rate of haemolysis. This essay is based on the evaluation of the alterations of red cell membranes in the presence of an eventual xenobiotic. Red blood cells are the main cells in circulation, and they are responsible for transporting oxygen; in fact, any alterations of this process could be lethal. The plasma membrane of red blood cells is a multi-component structure such as to confer to these cells their characteristic biconcave shape, high flexibility, elasticity and deformability. However, there are clear signs of cellular suffering if there are any alterations to this structure. One method of toxicity assessment is based on measurement of the efflux of haemoglobin from suspended red blood cells. Haemolysis, and therefore the loss of haemoglobin, is the signal stability of the cell membrane of the erythrocytes. In recent years, the discovery of programmed cell death in mammalian red blood cells presented a diversification of the response to injury by these a-nucleated cells. This review shows that mammals' erythrocytes might serve well as a model cell to study on the cellular and molecular mechanisms of many treatments. Copyright © 2015 John Wiley & Sons, Ltd.

Description: Satellite CO 2 retrievals from the Greenhouse gases Observing SATellite (GOSAT), Atmospheric Infrared Sounder (AIRS), and Tropospheric Emission Spectrometer (TES) and in-situ measurements from the Earth System Research Laboratory (NOAA-ESRL) Surface CO 2 and Total Carbon Column Observing Network (TCCON) are utilized to explore the CO 2 variability at different altitudes. A multiple regression method is used to calculate the CO 2 annual cycle and semiannual cycle amplitudes from different data sets. The CO 2 annual cycle and semiannual cycle amplitudes for GOSAT X CO2 and TCCON X CO2 are consistent, but smaller than those seen in the NOAA-ESRL surface data. The CO 2 annual and semiannual cycles are smallest in the AIRS mid-tropospheric CO 2 compared with other data sets in the northern hemisphere. The amplitudes for the CO 2 annual cycle and semiannual cycle from GOSAT, TES, and AIRS CO 2 are small and comparable to each other in the southern hemisphere. Similar regression analysis is applied to the Model for OZone And Related chemical Tracers-2 (MOZART-2) and CarbonTracker model CO 2 . The convolved model CO 2 annual cycle and semiannual cycle amplitudes are similar to those from the satellite CO 2 retrievals, although the models tend to underestimate the CO 2 seasonal cycle amplitudes in the northern hemisphere mid-latitudes and underestimate the CO 2 semi-annual cycle amplitudes in the high latitudes. These results can be used to better understand the vertical structures for the CO 2 annual cycle and semiannual cycle and help identify deficiencies in the models, which are very important for the carbon budget study. This article is protected by copyright. All rights reserved.

Description: This manuscript presents a simple yet effective method to account for uncertainty in hydrologic ensemble forecasting applications. Most operational hydrologic ensemble forecasting systems only account for uncertainty in future climate (e.g. precipitation) forcings, ignoring other sources of uncertainty (e.g. model error). The result can be under-dispersive and overconfident forecasts. Ensemble dressing is a form of statistical post-processing to include information about the uncertainty of individual ensemble members. First, the historical simulations can be corrected to remove systematic biases. Next, the simulated and observed flow data are transformed to ensure that model residuals can be fitted to a distribution (e.g. Normal); this study uses a 2-parameter log-sinh transformation. Model residuals in transformed space determine the width of the error distribution. Ensemble forecasts are then generated and transformed. Each ensemble is dressed with the error distribution, the results untransformed and finally a probabilistic forecast is derived from the collective distribution of the dressed ensembles. The method is applied to 128 catchments in southeast Australia, demonstrating that the raw ensemble can be made reliable through the use of this dressing method. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Mid-tropospheric CO2 retrieved from the Atmospheric Infrared Sounder (AIRS) was used to investigate CO2 interannual variability over the Indo-Pacific region. A signal with periodicity around two years was found for the AIRS mid-tropospheric CO2 for the first time, which is related to the Tropospheric Biennial Oscillation (TBO) associated with the strength of the monsoon. During a strong (weak) monsoon year, the Western Walker Circulation is strong (weak), resulting in enhanced (diminished) CO2 transport from the surface to the mid-troposphere. As a result, there are positive (negative) CO2 anomalies at mid-troposphere over the Indo-Pacific region. We simulated the influence of the TBO on the mid-tropospheric CO2 over the Indo-Pacific region using the MOZART-2 model, and results were consistent with observations, although we found the TBO signal in the model CO2 is to be smaller than that in the AIRS observations.

Description: Flash flooding is one of the most hazardous natural events, and it is frequently responsible for loss of life and severe damage to infrastructure and the environment. Research into the use of new modelling techniques and data types in flash flood forecasting has increased over the past decade, and this paper presents a review of recent advances that have emerged from this research. In particular, we focus on the use of quantitative precipitation estimates and forecasts, the use of remotely sensed data in hydrological modelling, developments in forecasting models and techniques, and uncertainty estimates. Over the past decade flash flood forecast lead-time has expanded up to six hours due to improved rainfall forecasts. However the largest source of uncertainty of flash flood forecasts remains unknown future precipitation. An increased number of physically-based hydrological models have been developed and used for flash flood forecasting and they have been found to give more plausible results when compared with the results of conceptual, statistical, and neural network models. Among the three methods for deciding flash flood occurrence discussed in this review, the rainfall comparison method (flash flood guidance) is most commonly used for flash flood forecasting as it is easily understood by the general public. Unfortunately no existing model is capable of making reliable flash flood forecasts in urban watersheds even though the incidence of urban flash flooding is increasing due to increasing urbanization. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Since 2011, the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) and three major river forecasting centers of the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) have discontinued a long-standing practice of publishing consensus water supply forecasts in western U.S. river basins.

Description: This manuscript presents a simple yet effective method to account for uncertainty in hydrologic ensemble forecasting applications. Most operational hydrologic ensemble forecasting systems only account for uncertainty in future climate (e.g. precipitation) forcings, ignoring other sources of uncertainty (e.g. model error). The result can be under-dispersive and overconfident forecasts. Ensemble dressing is a form of statistical post-processing to include information about the uncertainty of individual ensemble members. First, the historical simulations can be corrected to remove systematic biases. Next, the simulated and observed flow data are transformed to ensure that model residuals can be fitted to a distribution (e.g. Normal); this study uses a 2-parameter log-sinh transformation. Model residuals in transformed space determine the width of the error distribution. Ensemble forecasts are then generated and transformed. Each ensemble is dressed with the error distribution, the results untransformed and finally a probabilistic forecast is derived from the collective distribution of the dressed ensembles. The method is applied to 128 catchments in southeast Australia, demonstrating that the raw ensemble can be made reliable through the use of this dressing method. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Knowledge of the relative contributions of phytoplankton size classes to zooplankton biomass is necessary to understand food-web functioning and response to climate change. During the DEep Water formation EXperiment (DEWEX), conducted in the north-west Mediterranean Sea in winter (February) and spring (April) of 2013, we investigated phytoplankton-zooplankton trophic links in contrasting oligotrophic and eutrophic conditions. Size fractionated particulate matter (pico, nano and micro POM) and zooplankton (64 to 〉 4000 μm) composition and carbon and nitrogen stable isotope ratios were measured inside and outside of the nutrient rich deep convection zone in the central Liguro-Provencal basin. In winter, phytoplankton biomass was low (0.28 mg.m −3 ) and evenly spread among pico, nano and micro phytoplankton. Using an isotope mixing model we estimated average contributions to zooplankton biomass by pico, nano and micro POM of 28, 59 and 15% respectively. In spring, the nutrient poor region outside of the convection zone had low phytoplankton biomass (0.58 mg.m −3 ) and was dominated by pico/nano phytoplankton. Estimated average contributions to zooplankton biomass by pico, nano and micro POM were 64, 28 and 10% respectively, although the model did not differentiate well between pico and nano POM in this region. In the deep convection zone, spring phytoplankton biomass was high (1.34 mg.m −3 ) and dominated by micro/nano phytoplankton. Estimated average contributions to zooplankton biomass by pico, nano and micro POM were 42, 42 and 20% respectively, indicating that a large part of the microphytoplankton biomass may have remained ungrazed.

Description: The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic-levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears ( Ursus maritimus ) are apex predators that primarily consume benthic and pelagic-feeding ice-associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas. Fasting status (≥ 7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983-1999 and 2000-2016 and was related to an index of ringed seal body condition. This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in Chukchi Sea polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggest that polar bears may be a useful indicator species. Further, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic level productivity in these marine ecosystems. This article is protected by copyright. All rights reserved.

Description: Evaluating plant community response to atmospheric CO 2 rise is critical to predicting ecosystem level change. Freshwater lakes offer a model system for examining CO 2 effects as submersed macrophyte species differ greatly in their growth responses to CO 2 enrichment, and free CO 2 concentrations among these habitats show a wide range of natural, spatial variation. We determined free CO 2 concentrations in the water column and sediment porewater in littoral zones with pH〈6.0 in Adirondack Mountain (NY, USA) lakes, and derived a community CO 2 responsiveness index (CCRI) based on quantitative sampling of 15 submersed macrophyte communities coupled with greenhouse-derived growth responses to CO 2 enrichment of constituent species to test two hypotheses: (1) CCRI, which is higher for communities dominated by species with greater growth responses to CO 2 enrichment, is positively correlated to free [CO 2 ] in the water column, and (2) in natural communities, the percent of sediment CO 2 -using species, which are relatively unresponsive to CO 2 enrichment, is negatively correlated to free [CO 2 ]. A significant positive correlation (P=0.003) between our physiologically-based CCRI and the concentration of free CO 2 in the water column supported our primary hypothesis that sites with higher levels of free CO 2 are dominated by species with greater growth responses to CO 2 enrichment. Our CCRI is also highly significantly correlated (P〈0.001) to the first axis scores for the same vegetation data from polar ordination. Finally, the relative importance of species that use sediment CO 2 as a photosynthetic carbon source is significantly negatively correlated (P = 0.029) with the concentration of free CO 2 in the water column. Our results indicate that natural variations in CO 2 levels are important determinants of submersed macrophyte community composition. Further, we demonstrate the utility of a physiologically-based index of community composition, our CCRI, as an ecologically valid measure of community response to CO 2 . This article is protected by copyright. All rights reserved.