49 research outputs found

    Study of the earth's thermal history and magnetic field evolution using geodynamical models and geochemical constraints

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    The thermal history of the Earth, from planetary accretion and core differentiation up to the present time, is of paramount importance for understanding our planet. The thermal evolution of the core and the mantle dictate the generation of the Earth's internal magnetic field and its evolution through time. In this dissertation, I study scenarios for the thermal and magnetic evolution of the Earth, using numerical simulations for mantle convection and implementing recent geochemical models for the mantle and core. The conditions for which a magnetic field can be generated in the Earth's core are studied using parameterized models for energy and entropy. The model devised in this project couples the results of the numerical simulations with the parameterized models for the core, to produce a global thermal and magnetic history, with feed-back between events happening in the mantle and the core. The dissertation presents an analysis of the scenarios that can be constructed from implementing new constraints into the thermal models for the mantle and core and emphasizes the most relevant scenarios which can be applied to the Earth's evolution, consistent with physical parameters, and geochemical and magnetic constraints known to date. In addition, I discuss the relevance of some of the scenarios which appear incompatible with the Earth's evolution, but are reminiscent of the evolution of other terrestrial bodies. The results of this work show that the most successful scenarios for the thermal and magnetic evolution require the presence of small amounts of core internal heating in the form of radioactive potassium, or a slightly increased concentration of radioactive elements at the base of the mantle, due to isolated, if the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle primordial reservoirs. Successful scenarios are also obtained if the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle. If the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle

    A COLLABORATIVE MODEL FOR VIRTUAL ENTERPRISE

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    Collaborative process characteristics have three dimensions: actors, activities and action’s logic. The aim of this paper is to present a virtual portal’s model that helps managing consortiums. Our model based on dynamic e-collaboration and it has a modular structure, multilayer approach. System’s functionality of virtual enterprise is collaborative model is concern on users’ login, based on role and access control, searching and providing distributed resources, accessibility, metadata management and improved information’s management. Our proposal for developing solution offers a functional architecture of a virtual enterprise using dynamic e-collaboration and shared space.dynamic e-collaboration, multilayer solution, modular approach

    The Neonate with Minor Dysmorphisms

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    Congenital anomalies are present in at least 10% of all neonatal intensive care unit admissions, of whom many have an underlying genetic condition. About 50–60% of human congenital anomalies are of unknown etiology, and approximately one- third are caused by genetic factors. A smaller percentage of birth defects are the result of chromosomal aberrations and gene mutations. Around 1 in 40 or 2.5% of all newborns have a malformation at birth. This may be an isolated malformation or may occur together with other malformations and/or dysmorphic features as part of a malformation syndrome. Around 4000 malformation syndromes have now been delineated. Many are associated with medical problems and making a specific syndrome diagnosis can influence immediate medical management. However, the infant with dysmorphism often does not have a major malformation, and may simply have an appearance that is unusual compared with the general population and of unaffected close relatives. The chapter intends to provide semnificative data concerning the approach and management of a dysmorphic neonate, mainly when there are minor anomalies and will offer all those relevant data and try to establish a protocol guide for the approach of the dimorphic neonate

    IMPACT OF DIGITALIZATION IN MANAGEMENT OF INTERNATIONAL BUSINESS IN ORGANIC AGRICULTURE. WAYS TO RESPOND TO CHALLENGES. USH PRO BUSINESS, INTER -BIO, WALLACHIA HUB STUDY CASE

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    AbstractDigital technologies are used in an increasingly in everyday life, in any aspects of human activities. Pandemics like Corona Virus imposed stricter rules for health and people, most probably, will prefer to be safer with organic products. Even before the crises, organic agriculture especially was on the path to digitalization. Now we realize better that Digitally Conducted Organic Agri-food (DCOA) solutions will emerge even faster. This paper is investigating the trends of evolution of digital transformation in organic agri-food industry and their impact on trade flows with food products. We look at the new emerging business models triggered by the DCOA solutions and the managerial challenges this will require especially for innovative start ups, farmers and SMEs in agri-food sector. Finally, we argue that university led innovation ecosystem, like the study case presented, may offer knowledge hubs for farmers, processors and sector branch organizations in the organic sector

    Multilateral development banks – Strategic actors in the new economy?

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    The paper addresses the role of multilateral development banks in the new economic paradigm, built in the context of multiple crises with global impact. Multilateral development banks, in their capacity as promoters of governments’ policies are “invited/expected” to play a key role in the new geopolitical architecture, holding a competitive advantage in the provision of finance, which is linked to the design and implementation of structural reforms and programs of strengthening institutions controlled by governments. The paper aims to represent a signal regarding the strategic component and the synergies that multilateral development banks can determine. It highlights the tools that multilateral development banks have for selecting, monitoring and supporting programs and projects with regional and global impact. The paper describes the state of knowledge and reviews the specialised literature in the field of multilateral development banks, describes intervention channels and financing products of multilateral development banks, and discusses their impact on a European and regional level. The concluding remarks address the strategic role of multilateral development banks, their contribution to sustainable development goals and outline directions for future research

    High Prevalence of Hepatitis B Virus Markers in Romanian Adolescents With Human Immunodeficiency Virus Infection

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    <p>Abstract</p> <p>Background</p> <p>We evaluated the frequency of hepatitis coinfection in Romanian adolescents who were diagnosed with human immunodeficiency virus (HIV) infection prior to 1995.</p> <p>Methods</p> <p>One hundred sixty-one adolescents (13–18 years of age) with symptomatic HIV infection, but without signs of hepatic dysfunction, and 356 age-matched, HIV-uninfected controls underwent laboratory testing for markers of parenterally acquired hepatitis virus infection.</p> <p>Results</p> <p>Seventy-eight percent of HIV-infected adolescents had markers of past or present hepatitis B virus (HBV) infection, as compared with 32% of controls (<it>P </it>= .0001). The prevalence of HBV replicative markers was more than 5-fold higher in HIV-infected adolescents as compared with controls: 43.4% vs 7.9% (<it>P </it>= .0001), respectively, for hepatitis B surface antigen (HBsAg); and 11.2% vs 2.2% (<it>P </it>= .0001), respectively, for hepatitis B e antigen (HBeAg). The prevalence of HBsAg chronic carriers and the presence of HBV replicative markers was significantly higher in patients with immunologically defined AIDS (CD4+ cell counts < 200 cells/mcL): 59.6% vs 34.6% (<it>P </it>= .02) for HBsAg and 22.8% vs 5.7%, (<it>P </it>= .002) for HBV DNA. After 1 year of follow-up, the proportion of those who cleared the HBeAg was considerably lower in severely immunosuppressed coinfected patients: 4.7% vs 37.1% (<it>P </it>= .003). Four additional HIV-infected adolescents became HBsAg-positive over the term of follow-up (incidence rate, 24.9/1000 person-years), despite a record of immunization against hepatitis B.</p> <p>Conclusion</p> <p>A substantial percentage of HIV-infected and HIV-uninfected Romanian adolescents have evidence of past or present HBV infection. In HIV-infected adolescents, the degree of immunosuppression is correlated with persistence of HBV replicative markers, even in the absence of clinical or biochemical signs of liver disease.</p

    High Prevalence of Hepatitis B Virus Markers in Romanian Adolescents With Human Immunodeficiency Virus Infection

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    <p>Abstract</p> <p>Background</p> <p>We evaluated the frequency of hepatitis coinfection in Romanian adolescents who were diagnosed with human immunodeficiency virus (HIV) infection prior to 1995.</p> <p>Methods</p> <p>One hundred sixty-one adolescents (13–18 years of age) with symptomatic HIV infection, but without signs of hepatic dysfunction, and 356 age-matched, HIV-uninfected controls underwent laboratory testing for markers of parenterally acquired hepatitis virus infection.</p> <p>Results</p> <p>Seventy-eight percent of HIV-infected adolescents had markers of past or present hepatitis B virus (HBV) infection, as compared with 32% of controls (<it>P </it>= .0001). The prevalence of HBV replicative markers was more than 5-fold higher in HIV-infected adolescents as compared with controls: 43.4% vs 7.9% (<it>P </it>= .0001), respectively, for hepatitis B surface antigen (HBsAg); and 11.2% vs 2.2% (<it>P </it>= .0001), respectively, for hepatitis B e antigen (HBeAg). The prevalence of HBsAg chronic carriers and the presence of HBV replicative markers was significantly higher in patients with immunologically defined AIDS (CD4+ cell counts < 200 cells/mcL): 59.6% vs 34.6% (<it>P </it>= .02) for HBsAg and 22.8% vs 5.7%, (<it>P </it>= .002) for HBV DNA. After 1 year of follow-up, the proportion of those who cleared the HBeAg was considerably lower in severely immunosuppressed coinfected patients: 4.7% vs 37.1% (<it>P </it>= .003). Four additional HIV-infected adolescents became HBsAg-positive over the term of follow-up (incidence rate, 24.9/1000 person-years), despite a record of immunization against hepatitis B.</p> <p>Conclusion</p> <p>A substantial percentage of HIV-infected and HIV-uninfected Romanian adolescents have evidence of past or present HBV infection. In HIV-infected adolescents, the degree of immunosuppression is correlated with persistence of HBV replicative markers, even in the absence of clinical or biochemical signs of liver disease.</p

    C-Terminus Glycans with Critical Functional Role in the Maturation of Secretory Glycoproteins

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    The N-glycans of membrane glycoproteins are mainly exposed to the extracellular space. Human tyrosinase is a transmembrane glycoprotein with six or seven bulky N-glycans exposed towards the lumen of subcellular organelles. The central active site region of human tyrosinase is modeled here within less than 2.5 Å accuracy starting from Streptomyces castaneoglobisporus tyrosinase. The model accounts for the last five C-terminus glycosylation sites of which four are occupied and indicates that these cluster in two pairs - one in close vicinity to the active site and the other on the opposite side. We have analyzed and compared the roles of all tyrosinase N-glycans during tyrosinase processing with a special focus on the proximal to the active site N-glycans, s6:N337 and s7:N371, versus s3:N161 and s4:N230 which decorate the opposite side of the domain. To this end, we have constructed mutants of human tyrosinase in which its seven N-glycosylation sites were deleted. Ablation of the s6:N337 and s7:N371 sites arrests the post-translational productive folding process resulting in terminally misfolded mutants subjected to degradation through the mannosidase driven ERAD pathway. In contrast, single mutants of the other five N-glycans located either opposite to the active site or into the N-terminus Cys1 extension of tyrosinase are temperature-sensitive mutants and recover enzymatic activity at the permissive temperature of 31°C. Sites s3 and s4 display selective calreticulin binding properties. The C-terminus sites s7 and s6 are critical for the endoplasmic reticulum retention and intracellular disposal. Results herein suggest that individual N-glycan location is critical for the stability, regional folding control and secretion of human tyrosinase and explains some tyrosinase gene missense mutations associated with oculocutaneous albinism type I

    Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals

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    Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice

    GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

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    Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment
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