2,987 research outputs found

    A dynamic model of ballasted rail track with bituminous sub-ballast layer

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    The bituminous sub-ballast layer within the ballasted rail track allows some mechanical and environmental advantages. An analytical model of a ballasted rail track with sub-ballast layer has been proposed by considering the rail as viscous-elastic continuous beam discretely supported, at four levels of elasticity. The model was used to compare the mechanical performance of both ballasted track with and without bituminous sub-ballast layer. The results confirmed that the bituminous sub-ballast layer reduces the dynamic forces on the ground and achieves the technical objectives as reduction of ground borne vibrations and increase of the design life of the rail track

    Using simple sequence repeats in 9 brassica complex species to assess hypertrophic curd induction

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    Five Simple Sequence Repeats (SSRs) were used to assess the relationship between inflorescence characteristics and their allelic variation in 53 Brassica oleracea and Brassica wild relatives (n = 9). Curd morphometric traits, such as weight (CW), height (CH), diameter (CD1), shape (CS) inflorescence curvature angle (CA), and its curd stem diameter (CD2), were measured. The aim of the work was to analyze the relationships among the allelic patterns of the SSRs primers utilized, and their status of homo or heterozygosity registered at each locus, as well as the inflorescence morphometric traits in order to individuate genomic regions stimulating the hypertrophy of this reproductive organ. The relationships found explain the diversity among B. oleracea complex species (n = 9) for the inflorescence size and structure, allowing important time reduction during the breeding process by crossing wild species, transferring useful resistance, and organoleptic and nutraceutical traits. The five SSRs loci were BoABI1, BoAP1, BoPLD1, BoTHL1, and PBCGSSRBo39. According to the allelic variation ascertained, we evaluated the heterozygosity index (H) for each SSR above cited. The results showed a significant interaction between the H index of the BoPLD1 gene and the inflorescence characteristics, summarized by the First Principal Component (PC1) (p-value = 0.0244); we ascertained a negative correlation between the H index and inflorescence characteristics, namely CW, CH, CD1, CD2, CA. The homozygosity BoPLD1 alelles, indicated by the H index, affect the inflorescence characteristics and broccoli and cauliflower yields

    A proximity-based method to identify genomic regions correlated with a continuously varying environmental variable

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    Knowledge of markers in the human genome which show spatial patterns and display extreme correlation with different environmental determinants play an important role in understanding the factors which affect the biological evolution of our species. We used the genotype data of more than half a million single nucleotide polymorphisms (SNPs) from the data set Human Genome Diversity Panel (HGDP-CEPH -CEPH) and we calculated Spearman's correlation between absolute latitude and one of the two allele frequen- cies of each SNP. We selected SNPs with a correlation coefficient within the upper 1% tail of the distribution. We then used a criterion of proximity between significant variants to focus on DNA regions showing a continuous signal over a portion of the genome. Based on external information and genome annotations, we demonstrated that most regions with the strongest signals also have biological relevance. We believe this proximity requirement adds an edge to our novel method compared to the existing literature, highlighting several genes (for example DTNB, DOT1L, TPCN2, RELN, MSRA, NRG3) related to body size or shape, human height, hair color, and schizophrenia. Our approach can be applied generally to any measure of association between polymorphic frequencies and continuously varying environmental variable

    A dissipated energy comparison to evaluate fatigue resistance using 2PB

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    Flexural fatigue due to repeated traffic loading is a process of cumulative damage and one of the main failure modes of flexible pavement structures. Typically, micro-cracks originate at the bottom of an asphalt concrete layer due to horizontal tensile strains. Micro-cracking starts to propagate towards the upper layers under repeated loading which can lead to pavement failure. Different approaches are usually used to characterise fatigue resistance in asphalt mixtures including the phenomenological approach, the fracture mechanics approach and the dissipated energy approach. This paper presents a comparison of fatigue resistance calculated for different dissipated energy models using 2 Point Bending (2PB) at IFSTTAR in Nantes. 2PB tests have been undertaken under different loading and environmental conditions in order to evaluate the properties of the mixtures (stiffness, dissipated energy, fatigue life and healing effect)

    Age- and sex-related variations in platelet count in Italy: a proposal of reference ranges based on 40987 subjects' data

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    BACKGROUND AND OBJECTIVES: Although several studies demonstrated that platelet count is higher in women, decreases with age, and is influenced by genetic background, most clinical laboratories still use the reference interval 150-400×10(9) platelets/L for all subjects. The present study was to identify age- and sex-specific reference intervals for platelet count. METHODS: We analysed electronic records of subjects enrolled in three population-based studies that investigated inhabitants of seven Italian areas including six geographic isolates. After exclusion of patients with malignancies, liver diseases, or inherited thrombocytopenias, which could affect platelet count, reference intervals were estimated from 40,987 subjects with the non parametric method computing the 2.5° and 97.5° percentiles. RESULTS: Platelet count was similar in men and women until the age of 14, but subsequently women had steadily more platelets than men. The number of platelets decreases quickly in childhood, stabilizes in adulthood, and further decreases in oldness. The final result of this phenomenon is that platelet count in old age was reduced by 35% in men and by 25% in women compared with early infancy. Based on these findings, we estimated reference intervals for platelet count ×10(9)/L in children (176-452), adult men (141-362), adult women (156-405), old men (122-350) and, old women (140-379). Moreover, we calculated an extended reference interval that takes into account the differences in platelet count observed in different geographic areas. CONCLUSIONS: The age-, sex-, and origin-related variability of platelet count is very wide, and the patient-adapted reference intervals we propose change the thresholds for diagnosing both thrombocytopenia and thrombocytosis in Italy

    Serum Levels of Soluble IL-2R, CD4 and CD8 in Chronic Active HCV Positive Hepatitis

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    The aim of the present study was to compare serum levels of soluble forms of interleukin-2 receptor, CD4 and CD8, released by lymphocytes during activation ofthe immune system, in patients with histologically verified chronic active hepatitis associated to hepatitis C virus infection, with those in healthy subjects. Significantly higher levels of soluble IL-2R and soluble CD8 were found in patients with chronic active hepatitis compared with controls. In contrast no difference was found for soluble CD4 values in the two groups. No correlations were found for both sIL-2R and sCD8 and these two molecules with other parameters of liver function. These results indicate that in these patients there is a general activation of the immune system, but the lack of correlation with parameters of liver function strengthens the suggestion that this activation does not play a role in the pathogenesis of chronic type C hepatitis

    Ultra-processed food consumption and its correlates among Italian children, adolescents and adults from the Italian Nutrition & Health Survey (INHES) cohort study

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    Objective: To assess ultra-processed food (UPF) consumption and its socio-demographic, psychosocial and behavioural correlates in a general population of Italian children, adolescents and adults. Design: Cross-sectional telephone-based survey Setting: Italy, 2010-2013. Participants: In total, 9078 participants (5-97 years) from the Italian Nutrition & Health Survey. Dietary intakes were collected by a 1-d 24-h dietary recall. UPF was defined by the NOVA classification and expressed as percentage of total energies. Results: Average energy intake from UPF (95 % CI) was 17·3 % (17·1 %, 17·6 %) among adults and 25·9 % (24·8 %, 27·0 %) in children/adolescents. Top sources of UPF were processed meats (32·5 %) and bread substitutes (16·7 %). Among adults, age (β = -3·10; 95 % CI (-4·40, -1·80) for >65 years v. 20-40 years; βs are dimensionless) and residing in Southern Italy (β = -0·73; 95 % CI (-1·32, -0·14) v. Northern) inversely associated with UPF. Screen view during meals was directly linked to UPF, as well as poor self-rated health (β = 5·32; 95 % CI (2·66, 7·99)), adverse life events (β = 2·33; 95 % CI (1·48, 3·18)) and low sleep quality (β = 2·34; 95 % CI (1·45, 3·23)). Boys consumed two-point percent more UPF of the total energy than girls (β = 2·01; 95 % CI (0·20, 3·82)). For all ages, a Mediterranean diet was inversely associated with UPF (β = -4·86; 95 % CI (-5·53, -4·20) for good v. poor adherence in adults and (β = -5·08; 95 % CI (-8·38, -1·77) for kids). Conclusions: UPF contributes a modest proportion of energy to the diets of Italian adults while being one-quarter of the total energies in children/adolescents. UPF was associated with several psychosocial factors and eating behaviours. Increased adherence to Mediterranean diet would possibly result in lower UPF consumption
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