3,697 research outputs found

    Intensifying agricultural sustainability: an analysis of impacts and drivers in the development of ‘bright spots’

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    Food security / Farming systems / Sustainable agriculture / Productivity / Investment / Thailand / Palestine / Latin America / Africa

    UV Aerosol Indices from SCIAMACHY: introducing the SCattering Index (SCI)

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    The Absorbing Aerosol Index (AAI) is a useful tool for detecting aerosols that absorb UV radiation – especially in cases where other aerosol retrievals fail, such as over bright surfaces (e.g. desert) and in the presence of clouds. The AAI does not, however, consider contributions from scattering (hardly absorbing) aerosols and clouds: they cause negative AAI values and are usually disregarded. In this paper, we demonstrate the use of the AAI's negative counterpart, the SCattering Index (SCI) to detect scattering aerosols. Consideration of the full UV Aerosol Index scale is of importance if the Aerosol Index is to be used for the quantification of aerosol absorption in the future. <br><br> Maps of seasonally averaged SCI show significantly enhanced values in summer in Southeast USA and Southeast Asia, pointing to a high production of scattering aerosols (presumably mainly sulphate aerosols and secondary organic aerosols) in this season. The application of a cloud filter makes the presence of scattering aerosols even more clear. Radiative transfer calculations were performed to investigate the sensitivity of AAI and SCI to cloud parameters, and it is demonstrated that clouds cause significant SCI, in some special cases even small AAI values. The results from cloud modelling imply that cloud effects need to be taken into account when AAI and SCI are used in a quantitative manner. <br><br> The paper concludes with a comparison of aerosol parameters from AERONET and our Aerosol Indices (AAI and SCI) from SCIAMACHY, where reasonable agreement was found for six AERONET stations in Southeast USA, Southeast Asia, and Africa. These findings corroborate the suitability of SCI as a tool to detect scattering aerosols

    Relationship between ATSR fire counts and CO vertical column densities retrieved from SCIAMACHY onboard ENVISAT

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    SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric ChartographY) is the first instrument to allow retrieval of CO by measuring absorption in the near infrared from reflected and scattered sunlight instead of from thermal emission. Thus, in contrast to thermal-infrared satellites (MOPITT), SCIAMACHY is highly sensitive to the lower layers of the troposphere where the sources, such as biomass burning, are located, and where the bulk of the CO is usually found. In many regions of the world, the burning of vegetation has a repeating seasonal pattern, but the amount of CO emitted from biomass burning varies considerably from place to place. Here we present a study on the relationship between fire counts and CO vertical column densities (VCD) in different regions. These results are compared with the CO VCD from MOPITT, aerosol index, and NO_2 tropospheric VCD (TVCD) from SCIAMACHY, and the coupled chemistry climate model (CCM) ECHAM5/MESSY

    Global Monitoring of Atmospheric Trace Gases, Clouds and Aerosols from UV/vis/NIR Satellite Instruments: Currents Status and Near Future Perspectives

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    A new generation of UV/vis/near‐IR satellite instruments like GOME (since 1995), SCIAMACHY (since 2002), OMI (since 2004), and GOME‐2 (since 2006) allows to measure several important stratospheric and tropospheric trace gases like O_3, NO_2, OClO, HCHO, SO_2, BrO, and H_2O as well as clouds and aerosols from space. Because of its extended spectral range, the SCIAMACHY instrument also allows the retrieval of Greenhouse gases (CO_2, CH_4) and CO in the near IR. Almost all of the tropospheric trace gases are observed by these instruments for the first time. From satellite data it is possible to investigate the temporal and spatial variation. Also different sources can be characterised and quantified. The derived global distributions can serve as input and for the validation of atmospheric models. Here we give an overview on the current status of these new instruments and data products and their recent applications to various atmospheric and oceanic phenomena

    Immunohistochemical localization of collagen types I and VI in human skin wounds

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    A total of 74 human skin wounds were investigated and collagen types I and VI were localized in the wound area by immunohistochemistry. Collagen type I appeared in the form of ramifying string-like structures after approximately 5–6 days, but positive reactions in the form of a spot-like staining around isolated fibroblasts also occurred in a skin wound aged 4 days. Collagen VI was detectable after a post-infliction interval of at least 3 days showing a strongly positive reacting network associated with fibroblasts in the wound area. Both collagens appeared almost constantly after a wound age of 6–7 clays and could also be found in wounds aged a few months. Therefore, although a positive reaction for collagen type I in the form of string-like and ramifying structures around wound fibroblasts indicates a wound age of at least 5–6 days, a spot-like positive staining for collagen type I cannot exclude a wound age of at least 4 days. A positive staining for collagen type VI represents a post-infliction time of 3 days or more. The almost constant appearance of these collagen types suggests that negative results in a sufficient number of specimens indicate a wound age of less than 6–7 days, but cannot completely exclude longer post-infliction intervals. Since collagen type I and VI are also found in the granulation/scar tissue of lesions with advanced wound age, the immunohistochemical analysis of these proteins provides no further information for an age determination of older skin wounds

    The time-dependent localization of Ki 67 antigen-positive cells in human skin wounds

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    A total of 77 human skin wounds with a post-infliction interval between 3 h and 7 months were investigated and the proliferation marker antigen Ki 67 was visualized in paraffin sections using a specific monoclonal antibody (MIB). The re-built epidermal layer covering the former lesional area showed only a few basal cells positively staining for Ki 67 antigen. No enhanced reactivity was found when compared to uninjured skin. In basal cells of the epidermis adjacent to the wound area, however, varying numbers of positive cells occurred, but no information useful for a reliable time estimation of skin wounds could be obtained due to the considerable variability in the number of Ki 67 positive epidermal basal cells found in non-damaged skin. Fibroblastic cells in the wound area revealed an increased number of Ki 67-positive sites which could first be detected in a 1.5-day-old skin lesion. Positive results could be obtained in every specimen investigated after a post-infliction interval of 6 days up to 1.5 months. Only the scar tissue of the oldest wound examined (wound age 7 months) revealed no increase in the number of positively staining fibroblasts. Therefore, positive results indicate a wound age of at least approximately 1.5 days and the lack of an increased number of positive fibroblastic cells in a sufficient number of specimens indicates at a wound age of less than 6 days, but cannot totally exclude longer post-infliction intervals

    Effects of dental probing on occlusal surfaces - A scanning electron microscopy evaluation

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    The aim of this clinical-morphological study was to investigate the effects of dental probing on occlusal surfaces by scanning electron microscopy (SEM). Twenty sound occlusal surfaces of third molars and 20 teeth with initial carious lesions of 17- to 26-year-old patients (n = 18) were involved. Ten molars of each group were probed with a sharp dental probe (No. 23) before extraction; the other molars served as negative controls. After extraction of the teeth, the crowns were separated and prepared for the SEM study. Probing-related surface defects, enlargements and break-offs of occlusal pits and fissures were observed on all occlusal surfaces with initial carious lesions and on 2 sound surfaces, respectively. No traumatic defects whatsoever were visible on unprobed occlusal surfaces. This investigation confirms findings of light-microscopic studies that using a sharp dental probe for occlusal caries detection causes enamel defects. Therefore, dental probing should be considered as an inappropriate procedure and should be replaced by a meticulous visual inspection. Critical views of tactile caries detection methods with a sharp dental probe as a diagnostic tool seem to be inevitable in undergraduate and postgraduate dental education programmes. Copyright (c) 2007 S. Karger AG, Basel

    Run 2 Upgrades to the CMS Level-1 Calorimeter Trigger

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    The CMS Level-1 calorimeter trigger is being upgraded in two stages to maintain performance as the LHC increases pile-up and instantaneous luminosity in its second run. In the first stage, improved algorithms including event-by-event pile-up corrections are used. New algorithms for heavy ion running have also been developed. In the second stage, higher granularity inputs and a time-multiplexed approach allow for improved position and energy resolution. Data processing in both stages of the upgrade is performed with new, Xilinx Virtex-7 based AMC cards.Comment: 10 pages, 7 figure
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