ALBERT

Description: Maternal obesity is associated with large-for-gestational-age (LGA) neonates and programming of obesity-related cardiovascular disease in the offspring, however, the mechanisms that lead to the later are unclear. Presently, interpretations of NO-dependent changes in vascular function in LGA newborn from obese mothers are conflicting. Adiponectin improves endothelial function by increasing eNOS activity and NO production. We propose that LGAs from obese mothers present a diminished vascular response to adiponectin; thus, affecting eNOS and AMPK activation. Chorionic arteries, umbilical cord and primary cultures of umbilical artery endothelial cells (HUAEC) were collected at term (〉38 wks) from uncomplicated singleton pregnancies of LGA and adequate-for-gestational (AGA) newborn. Vascular reactivity of chorionic plate arteries was assessed by wire myography. mRNA expression of adiponectin receptors 1 (AdipoR1) and AdipoR2 in HUAEC was determined by qPCR. Protein expression of AdipoR1, AdipoR2, AMPK, phospho-AMPKα Thr172 , eNOS and phospho-eNOS Ser1177 after stimulation with AdipoRon was determined by Western Blot. Maximal adiponectin-induced chorionic artery relaxation in LGAs was diminished compared to control. In vitro studies showed no differences in expression of AdipoRs, total AMPK and, eNOS activation between groups; however, higher expression of total eNOS and AMPK activation in HUAEC of LGA relative to AGAs were observed. LGA HUAEC showed diminished NO production and eNOS activity compared to AGA in response to AdipoRon but no changes in AMPK activation. Placental endothelium of LGAs shows a diminished vascular response to adiponectin. Moreover, eNOS activation and adiponectin-dependent NO production is lower in HUAEC of LGA from obese mothers, indicating they present dysfuncional placental-endothelial responses. This article is protected by copyright. All rights reserved

Description: River flooding is among the most destructive of natural hazards globally, causing widespread loss of life, damage to infrastructure and economic deprivation. Societies are currently under increasing threat from such floods, predominantly from increasing exposure of people and assets in flood‐prone areas, but also as a result of changes in flood magnitude, frequency, and timing. Accurate flood hazard and risk assessment are therefore crucial for the sustainable development of societies worldwide. With a paucity of hydrological measurements, evidence from the field offers the only insight into truly extreme events and their variability in space and time. Historical, botanical, and geological archives have increasingly been recognized as valuable sources of extreme flood event information. These different archives are here reviewed with a particular focus on the recording mechanisms of flood information, the historical development of the methodological approaches and the type of information that those archives can provide. These studies provide a wealthy dataset of hundreds of historical and palaeoflood series, whose analysis reveals a noticeable dominance of records in Europe. After describing the diversity of flood information provided by this dataset, we identify how these records have improved and could further improve flood hazard assessments and, thereby, flood management and mitigation plans.

Description: ABSTRACT Granular materials submitted to uniaxial compression undergo pore space reduction due to mechanisms such as particle rearrangement and grain crushing. These changes in the internal structure of the material release energy in the form of elastic waves that can be detected by sensors sensitive to acoustic emission. In this study, Acoustic emission monitoring with a wavelet‐based signal processing technique is used to identify the various mechanisms occurring during high‐pressure sand compaction. Particle movement, grain failure, friction between grains and the surface of the compression cell and intergranular friction are studied. Acoustic emission data recorded during these simplified tests are used to characterize each phenomenon. Wavelet transform analyses allow the identification of useful features, making possible frequency discrimination among sliding, rolling, friction and grain fragmentation processes. For instance, we observe that at low stress, grain flow is characterized by the lowest centroid and peak frequencies, while at greater stresses, intergranular friction and grain fragmentation have the higher values. In the tests performed, the stress–strain evolution and final condition of the tested sand are broadly consistent, irrespective of the condition employed: continuous, stepwise or even variable loading rate or temperature. However, Acoustic emission data manifest much more complex behaviour (including thermal, load‐rate dependency and delayed fragmentation phenomena) than that suggested by stress–strain relationships. At low stress levels, grain flow (sliding/rolling) is a relevant strain‐accommodation mechanism, but so is crushing due to the effect of concentrated forces at the grain contact level. At high stresses, when crushing is generalized, intergranular friction is also a relevant phenomenon due to the increase in the coordination number produced by previous fragmentation.

Description: Enteric methane (CH 4 ) production from cattle contributes to global greenhouse gas emissions. Measurement of enteric CH 4 is complex, expensive and impractical at large scales; therefore, models are commonly used to predict CH 4 production. However, building robust prediction models requires extensive data from animals under different management systems worldwide. The objectives of this study were to (1) collate a global database of enteric CH 4 production from individual lactating dairy cattle; (2) determine the availability of key variables for predicting enteric CH 4 production (g/d per cow), yield [g/kg dry matter intake (DMI)], and intensity (g/kg energy corrected milk) and their respective relationships; (3) develop intercontinental and regional models and cross-validate their performance; and (4) assess the trade-off between availability of on-farm inputs and CH 4 prediction accuracy. The intercontinental database covered Europe (EU), the US (US), Chile (CL), Australia (AU), and New Zealand (NZ). A sequential approach was taken by incrementally adding key variables to develop models with increasing complexity. Methane emissions were predicted by fitting linear mixed models. Within model categories, an intercontinental model with the most available independent variables performed best with root mean square prediction error (RMSPE) as a percentage of mean observed value of 16.6, 14.4, and 19.8% for intercontinental, EU, and US regions, respectively. Less complex models requiring only DMI had predictive ability comparable to complex models. Enteric CH 4 production, yield, and intensity prediction models developed on an intercontinental basis had similar performance across regions, however, intercepts and slopes were different with implications for prediction. Revised CH 4 emission conversion factors for specific regions are required to improve CH 4 production estimates in national inventories. In conclusion, information on DMI is required for good prediction, and other factors such as dietary NDF concentration, improve the prediction. For enteric CH 4 yield and intensity prediction, information on milk yield and composition is required for better estimation. This article is protected by copyright. All rights reserved.

Description: One of the most intriguing, long-standing questions regarding Venus' atmosphere is the origin and distribution of the unknown UV-absorber, responsible for the absorption band detected at the near-UV and blue range of Venus' spectrum. In this work, we use data collected by MASCS spectrograph on board the MESSENGER mission during its second Venus flyby in June 2007 to address this issue. Spectra range from 0.3 μ m to 1.5 μ m including some gaseous H 2 O and CO 2 bands, as well as part of the SO 2 absorption band and the core of the UV absorption. We used the NEMESIS radiative transfer code and retrieval suite to investigate the vertical distribution of particles in the Equatorial atmosphere and to retrieve the imaginary refractive indices of the UV-absorber, assumed to be well mixed with Venus' small mode-1 particles. The results show an homogeneous Equatorial atmosphere, with cloud tops (height for unity optical depth) at 75±2 km above surface. The UV absorption is found to be centered at 0.34±0.03  μ m with a full width half maximum of 0.14±0.01 μ m. Our values are compared with previous candidates for the UV aerosol absorber, among which disulfur oxide (S 2 O) and dioxide disulfur (S 2 O 2 ) provide the best agreement with our results.

Description: Hybridization between wild species and their domestic congeners is considered a major threat for wildlife conservation. Genetic integrity of the European wildcat, for instance, is a concern as they are outnumbered by domestic cats by several orders of magnitude throughout its range. We genotyped 1,071 individual wildcat samples obtained from hair traps and roadkills collected across the highly fragmented forests of western Central Europe, in Germany and Luxembourg, to assess domestic cat introgression in wildcats in human-dominated landscapes. Analyses using a panel of 75 autosomal SNPs suggested a low hybridization rate, with 3.5% of wildcat individuals being categorized as F1, F2, or backcrosses to either parental taxon. We report that results based on a set of SNPs were more consistent than on a set of 14 microsatellite markers, showed higher accuracy to detect hybrids and their class in simulation analyses, and were less affected by underlying population structure. Our results strongly suggest that very high hybridization rates previously reported for Central Europe may be partly due to inadequate choice of markers and/or sampling design. Our study documents that an adequately selected SNP panel for hybrid detection may be used as an alternative to commonly applied microsatellite markers, including studies relying on noninvasively collected samples. In addition, our finding of overall low hybridization rates in Central European wildcats provides an example of successful wildlife coexistence in human-dominated, fragmented landscapes. ”We assess hyribization between wildcats and domestic cats in Germany and Luxembourg, and offer an explanation for greatly differing previous estimates, contrasting with those reported in our and other studies. We use microsatellites, SNPs and control region mtDNA sequences, as well as different sampling strategies (hair trapping and roadkill specimen collection) of 1.071 individuals. Our results showed that study setup concerning the choice of markers and sampling affect inferred hybridization rates. Our study documents very low hybridization rates between a wild and a domestic taxon despite close coexistence and widespread anthropogenic disturbance.”

Description: The level-set method is typically used to track and propagate the fire perimeter in wildland fire models. Herein, a high-order level-set method using fifth-order WENO scheme for the discretization of spatial derivatives and third-order explicit Runge-Kutta temporal integration is implemented within the Weather Research and Forecasting model wildland fire physics package, WRF-Fire. The algorithm includes solution of an additional partial differential equation for level-set reinitialization. The accuracy of the fire front shape and rate of spread in uncoupled simulations is systematically analyzed. It is demonstrated that the common implementation used by level-set-based wildfire models yields to rate-of-spread errors in the range 10 – 35% for typical grid sizes (Δ = 12.5 – 100 m) and considerably underestimates fire area. Moreover, the amplitude of fire-front gradients in the presence of explicitly resolved turbulence features is systematically underestimated. In contrast, the new WRF-Fire algorithm results in rate-of-spread errors that are lower than 1% and that become nearly grid independent. Also, the underestimation of fire area at the sharp transition between the fire front and the lateral flanks is found to be reduced by a factor of 7. A hybrid-order level-set method with locally reduced artificial viscosity is proposed, which substantially alleviates the computational cost associated with high-order discretizations while preserving accuracy. Simulations of the Last Chance wildfire demonstrate additional benefits of high-order accurate level-set algorithms when dealing with complex fuel heterogeneities, enabling propagation across narrow fuel gaps and more accurate fire backing over the lee side of no fuel clusters.

Description: Since the success of combined antiretroviral therapy, HIV-1-infected individuals are now living much longer. This increased life expectancy is accompanied by a higher prevalence of HIV-1 associated neurocognitive disorders. Rising too is the incidence in these patients of pathological hallmarks of Alzheimer's disease such as increased deposition of amyloid beta protein (Aβ). Although neurons are major sources of Aβ in the brain, astrocytes are the most numerous glial cells, therefore, even a small level of astrocytic Aβ metabolism could make a significant contribution to brain pathology. Neprilysin (NEP) is a decisive/crucial regulator of Aβ levels. We evaluated the effects of HIV-1 on Aβ deposition and the expression and activity of NEP in primary human astrocytes. Specifically, no differences in intracellular amyloid deposits were found between infected and control cells. However, primary cultures of infected astrocytes showed more extracellular Aβ levels compared to controls. This was accompanied by reduced expression of NEP and to a significant decrease on its activity. These results indicate that the presence of HIV-1 in the brain could contribute to the increase of the total burden of cerebral Aβ. This article is protected by copyright. All rights reserved