627 research outputs found

    Low birth weight leads to obesity, diabetes and increased leptin levels in adults: the CoLaus study.

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    Low birth weight is associated with increased rates of obesity, insulin resistance and type 2 diabetes, but the precise mechanisms for this association remain unclear. We aimed to assess the relationships between birth weight and markers of glucose homeostasis or obesity in adults. Cross-sectional population-based study on 1458 women and 1088 men aged 35-75 years living in Lausanne, Switzerland. Birth weight was self-reported and categorized into ≤ 2.5, 2.6-3.5, 3.6-4.0 and >4.0 kg. Body composition was assessed by bioimpedance. Leptin and adiponectin levels were measured by ELISA. Women with low birth weight (≤ 2.5 kg) had higher levels of fasting plasma glucose, insulin, HOMA, diabetes and metabolic syndrome; a non significant similar trend was seen in men. In both genders, height increased with birth weight, whereas a U-shaped association was found between birth weight and body mass index, waist circumference and body fat percentage. After adjusting for age, smoking status, physical activity and fat mass, an inverse association was found between leptin and birth weight categories: adjusted mean ± standard error 17.3 ± 0.7, 16.2 ± 0.3, 15.6 ± 0.5 and 14.0 ± 0.8 ng/dL for birth weight categories ≤ 2.5, 2.6-3.5, 3.6-4.0 and >4.0 kg, respectively, in women (p < 0.05) and 9.8 ± 0.8, 9.1 ± 03, 7.8 ± 0.4 and 7.7 ± 0.5 ng/dL in men (p < 0.05). An inverse association was also found between reported birth weight and leptin to fat mass ratio: mean ± standard error 0.77 ± 0.04, 0.73 ± 0.02, 0.69 ± 0.03 and 0.62 ± 0.04 in women (p < 0.05); 0.46 ± 0.05, 0.45 ± 0.02, 0.39 ± 0.02 and 0.38 ± 0.03 in men (p < 0.05). No differences in adiponectin levels were found between birth weight groups. Middle-aged adults born with a low weight present a higher prevalence of diabetes and obesity and also higher leptin levels and leptin to fat mass ratio than adults born with a normal weight. The higher leptin levels and leptin to fat mass ratio among adults born with a low weight might be related to nutritional factors during childhood or to the development of leptin resistance and/or higher leptin production by body fat unit. Subjects born with a low weight should be counselled regarding the risks of developing diabetes and/or cardiovascular disease

    Towards a high-precision measurement of the antiproton magnetic moment

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    The recent observation of single spins flips with a single proton in a Penning trap opens the way to measure the proton magnetic moment with high precision. Based on this success, which has been achieved with our apparatus at the University of Mainz, we demonstrated recently the first application of the so called double Penning-trap method with a single proton. This is a major step towards a measurement of the proton magnetic moment with ppb precision. To apply this method to a single trapped antiproton our collaboration is currently setting up a companion experiment at the antiproton decelerator of CERN. This effort is recognized as the Baryon Antibaryon Symmetry Experiment (BASE). A comparison of both magnetic moment values will provide a stringent test of CPT invariance with baryons.Comment: Submitted to LEAP 2013 conference proceeding

    Direct high-precision measurement of the magnetic moment of the proton

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    The spin-magnetic moment of the proton μp\mu_p is a fundamental property of this particle. So far μp\mu_p has only been measured indirectly, analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here, we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin-transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in units of the nuclear magneton μp=2.792847350(9)μN\mu_p=2.792847350(9)\mu_N. This measurement outperforms previous Penning trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty year old indirect measurement, in which significant theoretical bound state corrections were required to obtain μp\mu_p, by a factor of 3. By application of this method to the antiproton magnetic moment μpˉ\mu_{\bar{p}} the fractional precision of the recently reported value can be improved by a factor of at least 1000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons.Comment: published in Natur

    Demonstration of the Double Penning Trap Technique with a Single Proton

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    Spin flips of a single proton were driven in a Penning trap with a homogeneous magnetic field. For the spin-state analysis the proton was transported into a second Penning trap with a superimposed magnetic bottle, and the continuous Stern-Gerlach effect was applied. This first demonstration of the double Penning trap technique with a single proton suggests that the antiproton magnetic moment measurement can potentially be improved by three orders of magnitude or more

    Coastal scenic beauty and sensitivity at the balearic islands, spain: Implication of natural and human factors

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    Coastal areas globally are facing a significant range of environmental stresses, enhanced by climate change-related processes and a continuous increase of human activities. The economic benefits of tourism are well-known for coastal regions, but, very often, conflicts arise between short-term benefits and long-term conservation goals. Among beach user preferences, five parameters of greater importance stand out from the rest, i.e., safety, facilities, water quality, litter and scenery; the latter is the main concern of this study. A coastal scenic evaluation was carried out in the Balearic Islands and focused on two major issues: coastal scenic beauty together with sensitivity to natural processes and human pressure. The archipelago is renowned as a top international coastal tourist destination that receives more than 13.5 million visitors (2019). Impressive landscape diversity makes the Balearics Islands an ideal field for this research. In total, 52 sites, respectively located in Ibiza (11), Formentera (5), Mallorca (18) and Menorca (18), were field-tested. In a first step, coastal scenic beauty was quantified using the coastal scenic evaluation system (CSES) method, based on the evaluation of 26 physical and human parameters, and using weighting matrices parameters and fuzzy logic mathematics. An evaluation index (“D”) was obtained for each site, allowing one to classify them in one of the five scenic classes established by the method. Twenty-nine sites were included in class I, corresponding to extremely attractive sites (CSES), which were mainly observed in Menorca. Several sound measures were proposed to maintain and/or enhance sites’ scenic value. In a second step, scenic sensitivity was evaluated using a novel methodological approach that makes possible the assessment of three different coastal scenic sensitivity indexes (CSSI), i.e., the natural sensitivity index NSI, the human sensitivity index HSI and the total sensitivity index TSI. Future climate change trends and projection of tourism development, studied at municipality scale, were considered as correction factors. All the islands showed places highly sensitive to environmental processes, while sensitivity to human pressure was essentially observed at Ibiza and Mallorca. Thereafter, sites were categorized into one of three sensitive groups established by the methodology. Results obtained are useful in pointing out very sensitive sceneries as well as limiting, preventing and/or anticipating future scenic degradation linked to natural and human issues

    Genetic variation at CHRNA5-CHRNA3-CHRNB4 interacts with smoking status to influence body mass index

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    Cigarette smoking is associated with lower body mass index (BMI), and a commonly cited reason for unwillingness to quit smoking is a concern about weight gain. Common variation in the CHRNA5-CHRNA3-CHRNB4 gene region (chromosome 15q25) is robustly associated with smoking quantity in smokers, but its association with BMI is unknown. We hypothesized that genotype would accurately reflect smoking exposure and that, if smoking were causally related to weight, it would be associated with BMI in smokers, but not in never smokers

    Identification and validation of copy number variants using SNP genotyping arrays from a large clinical cohort.

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    BACKGROUND: Genotypes obtained with commercial SNP arrays have been extensively used in many large case-control or population-based cohorts for SNP-based genome-wide association studies for a multitude of traits. Yet, these genotypes capture only a small fraction of the variance of the studied traits. Genomic structural variants (GSV) such as Copy Number Variation (CNV) may account for part of the missing heritability, but their comprehensive detection requires either next-generation arrays or sequencing. Sophisticated algorithms that infer CNVs by combining the intensities from SNP-probes for the two alleles can already be used to extract a partial view of such GSV from existing data sets. RESULTS: Here we present several advances to facilitate the latter approach. First, we introduce a novel CNV detection method based on a Gaussian Mixture Model. Second, we propose a new algorithm, PCA merge, for combining copy-number profiles from many individuals into consensus regions. We applied both our new methods as well as existing ones to data from 5612 individuals from the CoLaus study who were genotyped on Affymetrix 500K arrays. We developed a number of procedures in order to evaluate the performance of the different methods. This includes comparison with previously published CNVs as well as using a replication sample of 239 individuals, genotyped with Illumina 550K arrays. We also established a new evaluation procedure that employs the fact that related individuals are expected to share their CNVs more frequently than randomly selected individuals. The ability to detect both rare and common CNVs provides a valuable resource that will facilitate association studies exploring potential phenotypic associations with CNVs. CONCLUSION: Our new methodologies for CNV detection and their evaluation will help in extracting additional information from the large amount of SNP-genotyping data on various cohorts and use this to explore structural variants and their impact on complex traits
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