697 research outputs found

    Characterization of Navassa National Wildlife Refuge: A preliminary report for NF-06-05 (NOAA ship "Nancy Foster", April 18-30, 2006)

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    Navassa is a small, undeveloped island in the Windward Passage between Jamaica and Haiti. It was designated a National Wildlife Refuge under the jurisdiction of the U.S. Fish and Wildlife Service in 1999, but the remote location makes management and enforcement challenging, and the area is regularly fished by artisanal fishermen from Haiti. In April 2006, the NOAA Center for Coastal Fisheries and Habitat Research conducted a research cruise to Navassa. The cruise produced the first high-resolution multibeam bathymetry for the area, which will facilitate habitat mapping and assist in refuge management. A major emphasis of the cruise was to study the impact of Haitian fishing gear on benthic habitats and fish communities; however, in 10 days on station only one small boat was observed with five fishermen and seven traps. Fifteen monitoring stations were established to characterize fish and benthic communities along the deep (28-34 m) shelf, as these areas have been largely unstudied by previous cruises. The fish communities included numerous squirrelfishes, triggerfishes, and parrotfishes. Snappers and grouper were also present but no small individuals were observed. Similarly, conch surveys indicated the population was in low abundance and was heavily skewed towards adults. Analysis of the benthic photoquadrats is currently underway. Other cruise activities included installation of a temperature logger network, sample collection for stable isotope analyses to examine trophic structure, and drop camera surveys to ground-truth habitat maps and overhead imagery. (PDF contains 58 pages

    Etude thermique expérimentale des suspensions non newtoniennes en écoulement dans une conduite horizontale à géométrie variable

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    Dans l'industrie Agro-alimentaire, de nouveaux produits, de plus en plus complexes pour les chercheurs, sont mis en consommation. Sur ce papier nous exposons les rĂ©sultats d‟une Ă©tude thermique expĂ©rimentale des suspensions non newtoniennes et pseudoplastiques en Ă©coulement dans une conduite horizontale Ă  gĂ©omĂ©trie variable. Ces suspensions sont constituĂ©es de grosses sphĂšres dures dans une solution de Tylose. Elle nous a permis de mettre en exergue les limites du dĂ©veloppement de la couche limite thermique dont la l‟augmentation est favorisĂ©e par la prĂ©sence de sphĂšres rigides dans le mĂ©lange. Lâ€ŸĂ©tude met en Ă©vidence, d‟une part, l‟interdĂ©pendance entre l‟hydrodynamique et la thermique des suspensions des particules dont le diamĂštre moyen d est de 4,4 mm et le rapport d‟aspect d/D est Ă©gal Ă  0,13 et d‟autre part, les effets convectifs des particules (perturbations de la couche limite) dans des Ă©coulements dans une conduite Ă  gĂ©omĂ©trie variable. Cette Ă©tude nous a permis de comprendre les mĂ©canismes de chauffage du mĂ©lange Ă  partir de la paroi en observant une amĂ©lioration de la qualitĂ© du transfert de chaleur avec la fraction volumique des sphĂšres dures et avec l‟utilisation d‟une conduite Ă  gĂ©omĂ©trie variable.Mots-clĂ©s: solide-liquide, suspensions, sphĂšres, thermique, concentration, hydrodynamique. Experimental thermal study of the non-newtonian suspensions flowing in a horizontal duct with variable geometryIn the Agri-Food industry, new products, more and more complex for researchers, are put into consumption. This paper presents the results of an experimental study of heating Non-Newtonian and pseudoplastic suspensions flowing in a horizontal pipe with variable geometry. These suspensions are composed of large hard spheres in a solution of Tylose. It helped to highlight the limits of the development of the thermal boundary layer, which the increase is enhanced by the presence of rigid spheres in the mixture. The study highlights the interdependence between hydrodynamics and thermal of the suspensions of particles with a mean diameter d is 4.4 mm and the aspect ratio d / D is equal to 0.13. It shows the convective effects of the particles (disturbances of the boundary layer) flowing in a duct with a variable geometry. This study helped us to understand the mechanisms of heating of the mixture from the wall observing an improvement in the quality of heat transfer with the volume fraction of hard spheres and with the use of a duct with variable geometry.Keywords: solid-liquid, suspension, sphere, thermal, concentration, hydrodynamics

    Measurement of the acoustic absorption coefficient of some local building materials for residential buildings using the Kundt tube method

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    Sound noise is a major societal problem, whose health, environmental and even economic impact is very important. According to the World Health Organization (WHO), noise is an acoustic phenomenon that produces an uncomfortable hearing sensation. Populations whose buildings are housed in areas at high risk of noise are exposed to multiple diseases resulting from noise pollution. To remedy this, it is important to think of choosing the right materials with higher acoustic absorption coefficient. The materials studied in this article are concrete, mortar, stabilized soil, which are commonly and most used materials in the construction of residential buildings. The present work consists of determining the sound absorption coefficient of each material indexed by the Kundt tube method in order to provide building technicians with the standards to be followed to improve the acoustic comfort of residential buildings. From the results obtained in this paper, it’s obvious sound absorption coefficients peaks in the low frequencies between 100 Hz and 500 Hz for the three materials. These sound absorption coefficients peaks are accented respectively at 0.74 for the stabilized earth; 0.85 for mortar and 0.94 for concrete

    Relation among perceived weight change, sedentary activities and sleep quality during covid-19 lockdown: A study in an academic community in Northern Italy

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    In Italy, COVID-19 lockdown was imposed from 8 March until 3 May 2020 with negative consequences on the lifestyles and health of people. Within this context, the paper aims: (i) to analyse the impact of COVID-19 lockdown on perceived weight changes; (ii) to evaluate factors associated with the perception of weight changes (Body Mass Index (BMI), sleep quality, time spent in sedentary activities), in an Italian academic community of students and workers. A total of 3666 participants took part in this cross-sectional study (2838 students and 828 workers, of whom 73.0% were female). T-test, Chi-square test and the two-way ANOVA were used. Results showed that 43.3% of participants perceived a weight gain. Workers experienced a more substantial increase in body weight (0.7 kg) compared to students (0.3 kg; p = 0.013). A significant difference between preobese/obese workers (0.9 kg) and students (−0.3 kg; p < 0.001) was found. Overall, 57.0% of the sample was characterized by high levels of sedentary activities. Sedentary people noticed a higher weight gain (0.4 kg) compared to less sedentary people (0.3 kg; p = 0.048). More than 45% of participants reported a worsening of sleep quality and showed a perceived increase in body weight (0.5 kg) in comparison to those who improved their sleep quality (no weight change; p = 0.001). Designing tailored interventions to promote health-related behaviours during lockdown periods is essential

    Normality ranges of urine oxidative stress markers (8-OHdG and isoprostane) in Italian people free from respiratory diseases-Preliminary results

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    BACKGROUND: The study of oxidative stress (OxS) is becoming increasingly important in respiratory disease research. To our knowledge, the reference ranges of urinary 8-hydroxy-deoxy-guanosine (8-OHdG) and 8-isoprostane (isoprostane), a DNA and a lipid oxidation product respectively, have not yet been determined in subjects without respiratory diseases. AIM: To assess the reference range of OxS markers in Italian people aged 20-64 free from respiratory diseases (controls). METHODS: 8-OHdG and isoprostane were measured in spot-urine samples collected in the frame of Gene-Environment Interactions in Respiratory Diseases (GEIRD) study, a nested multi-case control survey. The biomarkers levels were corrected on creatinine concentration. Only controls (n=239) were considered for the aim of this work. The possible effects of potential determinants on OxS-biomarkers were studied before determining the normality range in selected subgroups of controls. Multiple linear regression was fitted to data using the logarithm of 8OHdG or isoprostane as dependent variables and sex, age, season, smoke, body mass index, as covariates. The appropriate percentiles were calculated. RESULTS: Both 8OHdG and isoprostane concentrations were significantly higher in smokers than in non smokers (p=0.025 and 0.047 respectively), while the other covariates did not influence OxS. The 95% 8OHdG normality range in non smokers varied from 0.26 to 25.94 ng/mg. The 95% isoprostane reference interval was 0.03 -5.42 ng/mg in non smokers. CONCLUSION: Provisional 95% normality range for urinary 8OHdG and isoprostane were determined in subjects free from respiratory diseases

    CD90/Thy-1 is preferentially expressed on blast cells of high risk acute myeloid leukaemias

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    Different transformation mechanisms have been proposed for elderly acute myeloid leukaemia (AML) and secondary AML (sAML) when compared with de novo AML or AML of younger patients. However, little is known regarding differences in the immunophenotypic profile of blast cells in these diseases. We systematically analysed, by flow cytometry, 148 patients affected by de novo (100 cases) or sAML (48 cases). By defining a cut-off level of 20% of CD34+ cells co-expressing CD90, the frequency of CD90+ cases was higher in sAML (40%) versus de novo AML (6%, P < 0.001), elderly AML (>60 years) (24%) versus AML of younger patients (10%, P = 0.010) and poor- versus good-risk karyotypes (according to the Medical Research Council classification, P < 0.001). The correlation between CD90 expression, sAML and unfavourable karyotypes was confirmed by analysing the subset of CD34+ AML cases alone (91/148). Consistently, univariate analysis showed that expression of CD90 was statistically relevant in predicting a shorter survival in CD90+ AML patients (P = 0.042). Our results, demonstrating CD90 expression in AML with unfavourable clinical and biological features, suggest an origin of these diseases from a CD90-expressing haemopoietic progenitor and indicate the use of CD90 as an additional marker of prognostic value in AML

    Loss of MUTYH function in human cells leads to accumulation of oxidative damage and genetic instability

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    The DNA glycosylase MUTYH (mutY homolog (Escherichia coli)) counteracts the mutagenic effects of 8-oxo-7,8-dihydroguanine (8-oxodG) by removing adenine (A) misincorporated opposite the oxidized purine. Biallelic germline mutations in MUTYH cause the autosomal recessive MUTYH-associated adenomatous polyposis (MAP). Here we designed new tools to investigate the biochemical defects and biological consequences associated with different MUTYH mutations in human cells. To identify phenotype(s) associated with MUTYH mutations, lymphoblastoid cell lines (LCLs) were derived from seven MAP patients harboring missense as well as truncating mutations in MUTYH. These included homozygous p.Arg245His, p.Gly264TrpfsX7 or compound heterozygous variants (p.Gly396Asp/Arg245Cys, p.Gly396Asp/Tyr179Cys, p.Gly396Asp/Glu410GlyfsX43, p.Gly264TrpfsX7/Ala385ProfsX23 and p.Gly264TrpfsX7/Glu480del). DNA glycosylase assays of MAP LCL extracts confirmed that all these variants were defective in removing A from an 8-oxoG:A DNA substrate, but retained wild-type OGG1 activity. As a consequence of this defect, MAP LCLs accumulated DNA 8-oxodG in their genome and exhibited a fourfold increase in spontaneous mutagenesis at the PIG-A gene compared with LCLs from healthy donors. They were also hypermutable by KBrO3--a source of DNA 8-oxodG--indicating that the relatively modest spontaneous mutator phenotype associated with MUTYH loss can be significantly enhanced by conditions of oxidative stress. These observations identify accumulation of DNA 8-oxodG and a mutator phenotype as likely contributors to the pathogenesis of MUTYH variants

    Direct detection of brown adipose tissue thermogenesis in UCP1−/− mice by hyperpolarized 129Xe MR thermometry

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    Brown adipose tissue (BAT) is a type of fat specialized in non-shivering thermogenesis. While non-shivering thermogenesis is mediated primarily by uncoupling protein 1 (UCP1), the development of the UCP1 knockout mouse has enabled the study of possible UCP1-independent non-shivering thermogenic mechanisms, whose existence has been shown so far only indirectly in white adipose tissue and still continues to be a matter of debate in BAT. In this study, by using magnetic resonance thermometry with hyperpolarized xenon, we produce the first direct evidence of UCP1-independent BAT thermogenesis in knockout mice. We found that, following adrenergic stimulation, the BAT temperature of knockout mice increases more and faster than rectal temperature. While with this study we cannot exclude or separate the physiological effect of norepinephrine on core body temperature, the fast increase of iBAT temperature seems to suggest the existence of a possible UCP1-independent thermogenic mechanism responsible for this temperature increase

    A holistic multi-methodology for sustainable renovation

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    A review of the barriers for building renovation has revealed a lack of methodologies, which can promote sustainability objectives and assist various stakeholders during the design stage of building renovation/retrofitting projects. The purpose of this paper is to develop a Holistic Multi-methodology for Sustainable Renovation, which aims to deal with complexity of renovation projects. It provides a framework through which to involve the different stakeholders in the design process to improve group learning and group decision-making, and hence make the building renovation design process more robust and efficient. Therefore, the paper discusses the essence of multifaceted barriers in building renovation regarding cultural changes and technological/physical changes. The outcome is a proposal for a multi-methodology framework, which is developed by introducing, evaluating and mixing methods from Soft Systems Methodologies (SSM) with Multiple Criteria Decision Making (MCDM). The potential of applying the proposed methodology in renovation projects is demonstrated through a case study
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