46 research outputs found

    Drift Corrected Trends and Periodic Variations in MIPAS IMK/IAA Ozone Measurements

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    Drifts, trends and periodic variations were calculated from monthly zonally averaged ozone profiles. The ozone profiles were derived from level-1b data of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) by means of the scientific level-2 processor run by the Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK). All trend and drift analyses were performed using a multilinear parametric trend model which includes a linear term, several harmonics with period lengths from 3 to 24 months and the quasi-biennial oscillation (QBO). Drifts at 2-sigma significance level were mainly negative for ozone relative to Aura MLS and Odin OSIRIS and negative or near zero for most of the comparisons to lidar measurements. Lidar stations used here include those at Hohenpeissenberg (47.8° N, 11.0 ° E), Lauder (45.0 ° S, 169.7 ° E), Mauna Loa (19.5 ° N, 155.6 ° W), Observatoire Haute Provence (43.9 ° N, 5.7 ° E) and Table Mountain (34.4 ° N, 117.7 ° W). Drifts against the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) were found to be mostly insignificant. The assessed MIPAS ozone trends cover the time period of July 2002 to April 2012 and range from -0.56 ppmv decade-1 to +0.48 ppmv decade-1 (-0.52 ppmv decade-1 to +0.47 ppmv decade-1 when displayed on pressure coordinates) depending on altitude/ pressure and latitude. From the empirical drift analyses we conclude that the real ozone trends might be slightly more positive/ less negative than those calculated from the MIPAS data, by conceding the possibility of MIPAS having a very small (approximately within -0.3 ppmv decade-1 negative drift for ozone. This leads to drift-corrected trends of -0.41 ppmv decade-1 to +0.55 ppmv decade-1 (-0.38 ppmv decade-1 to +0.53 ppmv decade-1 when displayed on pressure coordinates) for the time period covered by MIPAS Envisat measurements, with very few negative and large areas of positive trends at mid-latitudes for both hemispheres around and above 30 km (similar to 10 hPa). Negative trends are found in the tropics around 25 and 35 km (similar to 25 and 5 hPa), while an area of positive trends is located right above the tropical tropopause. These findings are in good agreement with the recent literature. Differences of the trends compared with the recent literature could be explained by a possible shift of the subtropical mixing barriers. Results for the altitude-latitude distribution of amplitudes of the quasi-biennial, annual and the semi-annual oscillation are overall in very good agreement with recent findings

    Slow Molecules Produced by Photodissociation

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    A simple method to control molecular translation with a chemical reaction is demonstrated. Slow NO molecules have been produced by partially canceling the molecular beam velocity of NO2_2 with the recoil velocity of the NO photofragment. The NO2_2 molecules were photodissociated using a UV laser pulse polarized parallel to the molecular beam. The spatial profiles of NO molecules showed two peaks corresponding to decelerated and accelerated molecules, in agreement with theoretical prediction. A significant portion of the decelerated NO molecules stayed around the initial dissociation positions even several hundred nanoseconds after their production.Comment: 17 pages, 4 figure

    Speech Communication

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    Contains reports on five research projects.C.J. Lebel FellowshipNational Institutes of Health (Grant 5 T32 NS07040)National Institutes of Health (Grant 5 R01 NS04332)National Science Foundation (Grant 1ST 80-17599)U.S. Navy - Naval Electronic Systems Command Contract (N00039-85-C-0254)U.S. Navy - Naval Electronic Systems Command Contract (N00039-85-C-0341)U.S. Navy - Naval Electronic Systems Command Contract (N00039-85-C-0290

    Machine Learning based histology phenotyping to investigate the epidemiologic and genetic basis of adipocyte morphology and cardiometabolic traits

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    Genetic studies have recently highlighted the importance of fat distribution, as well as overall adiposity, in the pathogenesis of obesity-associated diseases. Using a large study (n = 1,288) from 4 independent cohorts, we aimed to investigate the relationship between mean adipocyte area and obesity-related traits, and identify genetic factors associated with adipocyte cell size. To perform the first large-scale study of automatic adipocyte phenotyping using both histological and genetic data, we developed a deep learning-based method, the Adipocyte U-Net, to rapidly derive mean adipocyte area estimates from histology images. We validate our method using three state-of-the-art approaches; CellProfiler, Adiposoft and floating adipocytes fractions, all run blindly on two external cohorts. We observe high concordance between our method and the state-of-the-art approaches (Adipocyte U-net vs. CellProfiler: R2visceral = 0.94, P < 2.2 × 10-16, R2subcutaneous = 0.91, P < 2.2 × 10-16), and faster run times (10,000 images: 6mins vs 3.5hrs). We applied the Adipocyte U-Net to 4 cohorts with histology, genetic, and phenotypic data (total N = 820). After meta-analysis, we found that mean adipocyte area positively correlated with body mass index (BMI) (Psubq = 8.13 × 10-69, βsubq = 0.45; Pvisc = 2.5 × 10-55, βvisc = 0.49; average R2 across cohorts = 0.49) and that adipocytes in subcutaneous depots are larger than their visceral counterparts (Pmeta = 9.8 × 10-7). Lastly, we performed the largest GWAS and subsequent meta-analysis of mean adipocyte area and intra-individual adipocyte variation (N = 820). Despite having twice the number of samples than any similar study, we found no genome-wide significant associations, suggesting that larger sample sizes and a homogenous collection of adipose tissue are likely needed to identify robust genetic associations.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.C.A.G received a pump priming grant from Novo Nordisk to carry out this work. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.published version, accepted versio

    Speech Communication

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    Contains reports on five research projects.C.J. Lebel FellowshipNational Institutes of Health (Grant 5 T32 NSO7040)National Institutes of Health (Grant 5 R01 NS04332)National Institutes of Health (Grant 5 R01 NS21183)National Institutes of Health (Grant 5 P01 NS13126)National Institutes of Health (Grant 1 PO1-NS23734)National Science Foundation (Grant BNS 8418733)U.S. Navy - Naval Electronic Systems Command (Contract N00039-85-C-0254)U.S. Navy - Naval Electronic Systems Command (Contract N00039-85-C-0341)U.S. Navy - Naval Electronic Systems Command (Contract N00039-85-C-0290)National Institutes of Health (Grant RO1-NS21183), subcontract with Boston UniversityNational Institutes of Health (Grant 1 PO1-NS23734), subcontract with the Massachusetts Eye and Ear Infirmar

    Laser-guided direct writing: A novel method to deposit biomolecules for biosensors arrays

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    In this paper, we present a potential biomolecular patterning method, laser-guided direct writing guidance (LGDW), which may be utilized to deposit organic and bioactive particles for biosensor arrays. The instrumentation and operation of the LGDW system is introduced and the system settings used to achieve deposition are reported. The biomolecule, avidin, was deposited onto a substrate using LGDW to evaluate the possible damage from the laser on the biomolecules. The functionality of avidin after laser-based guidance was examined by exposing the deposited avidin molecules to its ligand, biotin. The results show some avidin retained its affinity to biotin after LGDW demonstrating little damage to the biomolecules
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