400 research outputs found

    Harmonisation Initiatives of Copernicus Data Quality Control

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    The Copernicus Space Component Data Access system (CSCDA) incorporates data contributions from a wide range of satellite missions. Through EO data handling and distribution, CSCDA serves a set of Copernicus Services related to Land, Marine and Atmosphere Monitoring, Emergency Management and Security and Climate Change. The quality of the delivered EO products is the responsibility of each contributing mission, and the Copernicus data Quality Control (CQC) service supports and complements such data quality control activities. The mission of the CQC is to provide a service of quality assessment on the provided imagery, to support the investigation related to product quality anomalies, and to guarantee harmonisation and traceability of the quality information. In terms of product quality control, the CQC carries out analysis of representative sample products for each contributing mission as well as coordinating data quality investigation related to issues found or raised by Copernicus users. Results from the product analysis are systematically collected and the derived quality reports stored in a searchable database. The CQC service can be seen as a privileged focal point with unique comparison capacities over the data providers. The comparison among products from different missions suggests the need for a strong, common effort of harmonisation. Technical terms, definitions, metadata, file formats, processing levels, algorithms, cal/val procedures etc. are far from being homogeneous, and this may generate inconsistencies and confusion among users of EO data. The CSCDA CQC team plays a significant role in promoting harmonisation initiatives across the numerous contributing missions, so that a common effort can achieve optimal complementarity and compatibility among the EO data from multiple data providers. This effort is done in coordination with important initiatives already working towards these goals (e.g. INSPIRE directive, CEOS initiatives, OGC standards, QA4EO etc.). This paper describes the main actions being undertaken by CQC to encourage harmonisation among space-based EO systems currently in service

    Effects of salt water on the ballistic protective performance of bullet-resistant body armour

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    Bullet-resistant body armour is used by law enforcement agencies and military personnel worldwide, often in inclement weather. Some fibre types used in body armour perform poorly when wet, resulting in a reduced level of protection; this is why most body armour protective elements are water-repellent treated and/or protected by a water-resistant cover. Some of the users operate in the maritime environment. The effect of salt water on body armour performance has not been previously reported. In this work the effect of soaking body armour in salt water and exposing body armour for up to 10 soaking and drying cycles in salt water was investigated. The effectiveness of the water-resistant cover was investigated by considering three cover conditions: (i) intact, (ii) cut and (iii) removed. Wet armour was heavier and provided significantly less protection from 9 mm Luger FMJ ammunition when compared to not-exposed armour irrespective of cover condition. A degradation in performance of armours exposed to soaking and drying cycles was noted, but this was similar across all regimes considered (one, three, five and ten cycles) and not as great as for wet armours

    Atypical presentation of angiosarcoma of the scalp in the setting of Human Immunodeficiency Virus (HIV)

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    <p>Abstract</p> <p>Background</p> <p>Angiosarcoma of the head and neck is an uncommon, aggressive malignant entity most commonly found in elderly Caucasian males. We present a case in a young black female with co-existing HIV. The atypical gender, age and race of the patient reflect the unusual clinical presentation of this case of angiosarcoma, attributable to the patient's HIV status.</p> <p>Case presentation</p> <p>A 22 year old patient presented with a large unresectable lesion over the occiput with surrounding ulceration, satellite lesions and associated lymphadenopathy. She is HIV-infected with a CD4 count of 360 cells/Ī¼l. She was not on antiretroviral treatment based on South African treatment guidelines advocating antiretroviral treatment when the CD4 count is below 200 cells/Ī¼l, in the absence of other AIDS-defining illnesses.</p> <p>The patient was treated with a course of ifosfamide and anthracyline based chemotherapy. Disease progression was noted on chemotherapy and she was subsequently palliated with a course of radiotherapy. She had a satisfactory response with an improvement in local symptoms. She is currently receiving symptomatic care.</p> <p>Conclusions</p> <p>South Africa is at the epicenter of the HIV epidemic. Consequently, the management of patients in the field of oncology in our clinical practice is often burdened with malignancies manifesting with an atypical disease presentation and clinical course.</p

    Economic burden of livestock disease and drought in Northern Tanzania

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    Livestock-dependent communities face considerable livestock disease and drought risk, which can impact herd value, income and consumption. This paper summarizes economic data collected from 404 households in Arusha and Manyara regions of Northern Tanzania in 2016. They provide estimates for (i) herd loss due to disease and drought as a fraction of herd value and income, (ii) the relative risk of disease and drought in small versus large ruminants and (iii) the relationship between livestock disease outcomes and household expenditures. We find that disease and drought losses comprise 10 to 4% of sheep, cattle and goat herd value, and amount to an estimated 62.1% of household income. The drought and disease risk ratios for small versus large ruminants indicate that small stock face higher disease risk, while large ruminants are affected more by drought. Furthermore, cattle abortions are negatively related to schooling expenditure and positively associated with increases in off-farm food expenditure related to livestock management, presumably through increased investments in prevention and therapy. These results suggest that climatic variability and livestock diseases are an important source of economic vulnerability and reducing this burden may help alleviate poverty in livestock-dependent communities

    Preferences about Future Alzheimerā€™s Disease Treatments Elicited through an Online Survey Using the Threshold Technique

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    Background: Treatments aiming at slowing down the progression of Alzheimerā€™s disease (AD) may soon become available. However, information about the risks that people are willing to accept in order to delay the progression of the disease is limited.Objective: To determine the trade-offs that individuals are willing to make between the benefits and risks of hypothetical treatments for AD, and the extent to which these trade-offs depend on individualsā€™ characteristics and beliefs about medicines.Design: Online, cross-sectional survey study.Setting: Population in the UK. Public link to the survey available at the websites of Alzheimerā€™s Research UK and Join Dementia Research.Participants: Everyone self-reported ā‰„18 years old was eligible to participate. A total of 4384 people entered the survey and 3658 completed it.Measurements: The maximum acceptable risks (MARs) of participants for moderate and severe adverse events in exchange for a 2-year delay in disease progression. The risks were expressed on ordinal scales, from &lt;10% to ā‰„50%, above a pre-existing risk of 30% for moderate adverse events and 10% for severe adverse events. We obtained the population median MARs using log-normal survival models and quantified the effects of individualsā€™ characteristics and beliefs about medicines in terms of acceleration factors.Results: For the moderate adverse events, 26% of the participants had a MAR ā‰„50%, followed by 25% of the participants with a MAR of 10 to &lt;20%, giving an estimated median MAR of 25.4% (95% confidence interval [CI] 24.5 to 26.3). For the severe adverse events, 43% of the participants had a MAR &lt;10%, followed by 25% of the participants with a MAR of 10 to &lt;20%, resulting in an estimated median MAR of 12.1% (95%CI 11.6 to 12.5). Factors that were associated with the individualsā€™ MARs for one or both adverse events were age, gender, educational level, living alone, and beliefs about medicines. Whether or not individuals were living with memory problems or had experience as a caregiver had no effect on the MARs for any of the adverse events.Conclusion: Trade-offs between benefits and risks of AD treatments are heterogeneous and influenced by individualsā€™ characteristics and beliefs about medicines. This heterogeneity should be acknowledged during the medicinal product decision-making in order to fulfil the needs of the various subpopulations.</p

    First principles investigation of exchange interactions in quasi-one-dimensional antiferromagnet CaV2O4

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    The effect of orbital degrees of freedom on the exchange interactions in the spin-1 quasi-one-dimensional antiferromagnet CaV2O4 is systematically studied. For this purpose a realistic low-energy model with the parameters derived from the first-principles calculations is constructed. The exchange interactions are calculated using both the theory of infinitesimal spin rotations near the mean-field ground state and the superexchange model, which provide a consistent description. The obtained behaviour of exchange interactions substantially differs from the previously proposed phenomenological picture based on the magnetic measurements and structural considerations, namely: (i) Despite quasi-one-dimensional character of the crystal structure, consisting of the zigzag chains of edge-sharing VO6 octahedra, the electronic structure is essentially three-dimensional, that leads to finite interactions between the chains; (ii) The exchange interactions along the legs of the chains appear to dominate; and (iii) There is a substantial difference of exchange interactions in two crystallographically inequivalent chains. The combination of these three factors successfully reproduces the behaviour of experimental magnetic susceptibility.Comment: 15 pages, 6 figures, supplementary materia

    The Same IĪŗBĪ± Mutation in Two Related Individuals Leads to Completely Different Clinical Syndromes

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    Both innate and adaptive immune responses are dependent on activation of nuclear factor ĪŗB (NF-ĪŗB), induced upon binding of pathogen-associated molecular patterns to Toll-like receptors (TLRs). In murine models, defects in NF-ĪŗB pathway are often lethal and viable knockout mice have severe immune defects. Similarly, defects in the human NF-ĪŗB pathway described to date lead to severe clinical disease. Here, we describe a patient with a hyper immunoglobulin Mā€“like immunodeficiency syndrome and ectodermal dysplasia. Monocytes did not produce interleukin 12p40 upon stimulation with various TLR stimuli and nuclear translocation of NF-ĪŗB was impaired. T cell receptorā€“mediated proliferation was also impaired. A heterozygous mutation was found at serine 32 in IĪŗBĪ±. Interestingly, his father has the same mutation but displays complex mosaicism. He does not display features of ectodermal dysplasia and did not suffer from serious infections with the exception of a relapsing Salmonella typhimurium infection. His monocyte function was impaired, whereas T cell function was relatively normal. Consistent with this, his T cells almost exclusively displayed the wild-type allele, whereas both alleles were present in his monocytes. We propose that the T and B cell compartment of the mosaic father arose as a result of selection of wild-type cells and that this underlies the widely different clinical phenotype

    Delineating Human B Cell Precursor Development With Genetically Identified PID Cases as a Model

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    B-cell precursors (BCP) arise from hematopoietic stem cells in bone marrow (BM). Identification and characterization of the different BCP subsets has contributed to the understanding of normal B-cell development. BCP first rearrange their immunoglobulin (Ig) heavy chain (IGH) genes to form the pre-B-cell receptor (pre-BCR) complex together with surrogate light chains. Appropriate signaling via this pre-BCR complex is followed by rearrangement of the Ig light chain genes, resulting in the formation, and selection of functional BCR molecules. Consecutive production, expression, and functional selection of the pre-BCR and BCR complexes guide the BCP differentiation process that coincides with corresponding immunophenotypic changes. We studied BCP differentiation in human BM samples from healthy controls and patients with a known genetic defect in V(D)J recombination or pre-BCR signaling to unravel normal immunophenotypic changes and to determine the effect of differentiation blocks caused by the specific genetic defects. Accordingly, we designed a 10-color antibody panel to study human BCP development in BM by flow cytometry, which allows identification of classical preB-I, preB-II, and mature B-cells as defined via BCR-related markers with further characterization by additional markers. We observed heterogeneous phenotypes associated with more than one B-cell maturation pathway, particularly for the preB-I and preB-II stages in which V(D)J recombination takes place, with asynchronous marker expression patterns. Next Generation Sequencing of complete IGH gene rearrangements in sorted BCP subsets unraveled their rearrangement status, indicating that BCP differentiation does not follow a single linear pathway. In conclusion, B-cell development in human BM is not a linear process, but a rather complex network of parallel pathways dictated by V(D)J-recombination-driven checkpoints and pre-BCR/BCR mediated-signaling occurring during B-cell production and selection. It can also be described as asynchronous, because precursor B-cells do not differentiate as full population between the different stages, but rather transit as a continuum, which seems influenced (in part) by V-D-J recombination-driven checkpoints
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