326 research outputs found
Serpagli, celebrating his 44th Silurian-research birthday
The editors are pleased to dedicate this volume on the Silurian of Sardinia to Enrico Serpagli, an outstanding personality of Italian palaeontology, who devoted substantial part of his professional life to marine faunas and biostratigraphy of Ordovician and Silurian sedimentary formations mostly of southern Sardinia. Two of the editors are former doctoral students of Enrico Serpagli and PS has been collaborating with him since his first, early postgradual visit to Sardinia in 1982
The Silurian of Sardinia
The present volume “The Silurian of Sardinia” is composed of two related components. The first part comprises seven contributions introduced by an historical overview on the studies already carried out on the Silurian faunas of Sardinia. It aims to delineate a comprehensive scenario of the Silurian of Sardinia within a proper geological setting. A global overview regarding the palaeoenvironment and palaeogeography is also provided. The second part of the volume consists of seven research papers that illustrate actual knowledge on major fossil groups encountered in the Silurian limestones and shales of southern Sardinia
Atmospheric Correction in Sentinel-2 Simplified Level 2 Product Prototype Processor: Technical Aspects of Design and Implementation
This paper presents the scientific and technical aspects of the Level 2A (atmospheric/topographic correction) for the Sentinel-2 Simplified Level 2 Product Prototype Processor (S2SL2PPP). Design aspects are partly fixed by the ESA as main customer. Together with the alternative atmospheric correction system MACCS, the developed chain based on ATCOR is used for the estimation of the following products: Atmosphere type, Bottom of atmosphere reflectance (including cirrus detection and correction), Aerosol optical thickness, and Water vapor.
Being a mono-temporal correction chain ATCOR requires a selection of the spectral bands for the estimation of Aerosol type, Aerosol optical thickness based on the dense dark vegetation method and Water vapor based on the atmospherically pre-corrected differential absorption method as well as an estimation of the best parameter set for these methods. The parameter set was estimated by a sensitivity analysis on a simulated top and bottom of atmosphere radiance/reflectance data based on radiative transfer simulations. The aerosol type is estimated by the comparison of the path radiances ratio to the ground truth path radiances ratio for the standard atmospheres, namely rural, urban, maritime, and desert. Aerosol optical thickness map and Water vapor map are initially estimated on the 20m pixel size data, then the maps are interpolated to the pixel size of 10m and the 10m reflectance data are estimated. The cirrus cloud map is created by the cirrus 1.38 µm band thresholding to the thin, medium, thick cirrus and cirrus clouds. Cirrus compensation is performed by correlating the cirrus band reflectance to the reflective region bands and subtraction of the cirrus contribution per band.
Validation of the chain is performed given the top of atmosphere data (as input) and bottom of atmosphere products (the reference). Estimated reflectance is assessed given the ground truth reflectance, Aerosol optical thickness is validated given the AERONET measurements, cirrus correction is validated using a pair of Landsat-8 scenes acquired for the same area with a small time difference. One scene is contaminated by cirrus cloud that has to be restored, while the other is cirrus free and used as reference. A comparison of the estimated products is also performed with an alternative atmospheric correction chain – FLAASH. The software is developed using the Interactive Data Language (IDL) and python.
This paper presents the scientific and technical aspects of the Level 2A (atmospheric/topographic correction) for the Sentinel-2 Simplified Level 2 Product Prototype Processor (S2SL2PPP). Design aspects are partly fixed by the ESA as main customer. Together with the alternative atmospheric correction system MACCS, the developed chain based on ATCOR is used for the estimation of the following products: Atmosphere type, Bottom of atmosphere reflectance (including cirrus detection and correction), Aerosol optical thickness, and Water vapor.
Being a mono-temporal correction chain ATCOR requires a selection of the spectral bands for the estimation of Aerosol type, Aerosol optical thickness based on the dense dark vegetation method and Water vapor based on the atmospherically pre-corrected differential absorption method as well as an estimation of the best parameter set for these methods. The parameter set was estimated by a sensitivity analysis on a simulated top and bottom of atmosphere radiance/reflectance data based on radiative transfer simulations. The aerosol type is estimated by the comparison of the path radiances ratio to the ground truth path radiances ratio for the standard atmospheres, namely rural, urban, maritime, and desert. Aerosol optical thickness map and Water vapor map are initially estimated on the 20m pixel size data, then the maps are interpolated to the pixel size of 10m and the 10m reflectance data are estimated. The cirrus cloud map is created by the cirrus 1.38 µm band thresholding to the thin, medium, thick cirrus and cirrus clouds. Cirrus compensation is performed by correlating the cirrus band reflectance to the reflective region bands and subtraction of the cirrus contribution per band.
Validation of the chain is performed given the top of atmosphere data (as input) and bottom of atmosphere products (the reference). Estimated reflectance is assessed given the ground truth reflectance, Aerosol optical thickness is validated given the AERONET measurements, cirrus correction is validated using a pair of Landsat-8 scenes acquired for the same area with a small time difference. One scene is contaminated by cirrus cloud that has to be restored, while the other is cirrus free and used as reference. A comparison of the estimated products is also performed with an alternative atmospheric correction chain – FLAASH. The software is developed using the Interactive Data Language (IDL) and python
Protein-membrane interaction and fatty acid transfer from intestinal fatty acid-binding protein to membranes: Support for a multistep process
Fatty acid transfer from intestinal fatty acid-binding protein (IFABP) to phospholipid membranes occurs during protein-membrane collisions. Electrostatic interactions involving the α-helical "portal" region of the protein have been shown to be of great importance. In the present study, the role of specific lysine residues in the α-helical region of IFABP was directly examined. A series of point mutants in rat IFABP was engineered in which the lysine positive charges in this domain were eliminated or reversed. Using a fluorescence resonance energy transfer assay, we analyzed the rates and mechanism of fatty acid transfer from wild type and mutant proteins to acceptor membranes. Most of the α-helical domain mutants showed slower absolute fatty acid transfer rates to zwitterionic membranes, with substitution of one of the lysines of the α2 helix, Lys27, resulting in a particularly dramatic decrease in the fatty acid transfer rate. Sensitivity to negatively charged phospholipid membranes was also reduced, with charge reversal mutants in the α2 helix the most affected. The results support the hypothesis that the portal region undergoes a conformational change during protein-membrane interaction, which leads to release of the bound fatty acid to the membrane and that the α2 segment is of particular importance in the establishment of charge-charge interactions between IFABP and membranes. Cross-linking experiments with a phospholipid-photoactivable reagent underscored the importance of charge-charge interactions, showing that the physical interaction between wild-type intestinal fatty acid-binding protein and phospholipid membranes is enhanced by electrostatic interactions. Protein-membrane interactions were also found to be enhanced by the presence of ligand, suggesting different collisional complex structures for holo- and apo-IFABP.Instituto de Investigaciones Bioquímicas de La Plat
Occurrence and Risk Factors for New Dependency on Chronic Care, Respiratory Support, Dialysis and Mortality in the First Year After Sepsis
Sepsis survival is associated with adverse outcomes. Knowledge about risk factors for adverse outcomes is lacking. We performed a population-based cohort study of 116,507 survivors of hospital-treated sepsis identified in health claims data of a German health insurance provider. We determined the development and risk factors for long-term adverse events: new dependency on chronic care, chronic dialysis, long-term respiratory support, and 12-month mortality. At-risk patients were defined by absence of these conditions prior to sepsis. Risk factors were identified using simple and multivariable logistic regression analyses. In the first year post-sepsis, 48.9% (56,957) of survivors had one or more adverse outcome, including new dependency on chronic care (31.9%), dialysis (2.8%) or respiratory support (1.6%), and death (30.7%). While pre-existing comorbidities adversely affected all studied outcomes (>4 comorbidities: OR 3.2 for chronic care, OR 4.9 for dialysis, OR 2.7 for respiratory support, OR 4.7 for 12-month mortality), increased age increased the odds for chronic care dependency and 12-month mortality, but not for dialysis or respiratory support. Hospital-acquired and multi-resistant infections were associated with increased risk of chronic care dependency, dialysis, and 12-month mortality. Multi-resistant infections also increased the odds of respiratory support. Urinary or respiratory infections or organ dysfunction increased the odds of new dialysis or respiratory support, respectively. Central nervous system infection and organ dysfunction had the highest OR for chronic care dependency among all infections and organ dysfunctions. Our results imply that patient- and infection-related factors have a differential impact on adverse life changing outcomes after sepsis. There is an urgent need for targeted interventions to reduce the risk
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