4,100 research outputs found
Interface Equations for Capillary Rise in Random Environment
We consider the influence of quenched noise upon interface dynamics in 2D and
3D capillary rise with rough walls by using phase-field approach, where the
local conservation of mass in the bulk is explicitly included. In the 2D case
the disorder is assumed to be in the effective mobility coefficient, while in
the 3D case we explicitly consider the influence of locally fluctuating
geometry along a solid wall using a generalized curvilinear coordinate
transformation. To obtain the equations of motion for meniscus and contact
lines, we develop a systematic projection formalism which allows inclusion of
disorder. Using this formalism, we derive linearized equations of motion for
the meniscus and contact line variables, which become local in the Fourier
space representation. These dispersion relations contain effective noise that
is linearly proportional to the velocity. The deterministic parts of our
dispersion relations agree with results obtained from other similar studies in
the proper limits. However, the forms of the noise terms derived here are
quantitatively different from the other studies
GAD Antibody Positivity Predicts Type 2 Diabetes in an Adult Population
OBJECTIVE-To evaluate the significance of GAD antibodies (GADAs) and family history for type 1 diabetes (FHT1) or type 2 diabetes (FHT2) in nondiabetic subjects. RESEARCH DESIGN AND METHODS-GADAs were analyzed in 4,976 nondiabetic relatives of type 2 diabetic patients or control subjects from Finland. Altogether, 289 (5.9%) were GADA(+)-a total of 253 GADA(+) and 2,511 GADA(-) subjects participated in repeated oral glucose tolerance tests during a median time of 8.1 years. The risk of progression to diabetes was assessed using Cox regression analysis. RESULTS-Subjects within the highest quartile of GADA(+) (GADA(high)(+)) had more often first-degree FHT1 (29.2 vs. 7.9%, P < 0.00001) and GADA(+) type 2 diabetic (21.3 vs. 13.7%, P = 0.002) or nondiabetic (26.4 vs. 13.3%, P = 0.010) relatives than GADA(-) subjects. During the follow-up, the GADA(+) subjects developed diabetes significantly more often than the GADA(-) subjects (36/253 [14.2%] vs. 134/2,511 [5.3%], P < 0.00001). GADA(high)(+) conferred a 4.9-fold increased risk of diabetes (95% CI 2.8-8.5) compared with GADA(-)-seroconversion to positive during the follow-up was associated with 6.5-fold (2.8-15.2) and first-degree FHT1 with 2.2-fold (1.2-4.1) risk of diabetes. Only three subjects developed type 1 diabetes, and others had a non-insulin-dependent phenotype 1 year after diagnosis. GADA(+) and GADA(-) subjects did not clinically differ at baseline, but they were leaner and less insulin resistant after the diagnosis of diabetes. CONCLUSIONS-GADA positivity clusters in families with type 1 diabetes or latent autoimmune diabetes in adults. GADA positivity predicts diabetes independently of family history of diabetes, and this risk was further increased with high GADA concentrations
Electrochemical Fouling of Dopamine and Recovery of Carbon Electrodes
A significant problem with implantable sensors is electrode fouling, which has been proposed as the main reason for biosensor failures in vivo. Electrochemical fouling is typical for dopamine (DA) as its oxidation products are very reactive and the resulting polydopamine has a robust adhesion capability to virtually all types of surfaces. The degree of DA fouling of different carbon electrodes with different terminations was determined using cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM) approach curves and imaging. The rate of electron transfer kinetics at the fouled electrode surface was determined from SECM approach curves, allowing a comparison of insulating film thickness for the different terminations. SECM imaging allowed the determination of different morphologies, such as continuous layers or islands, of insulating material. We show that heterogeneous modification of carbon electrodes with carboxyl-amine functionalities offers protection against formation of an insulating polydopamine layer, while retaining the ability to detect DA. The benefits of the heterogeneous termination are proposed to be due to the electrostatic repulsion between amino-functionalities and DA. Furthermore, we show that the conductivity of the surfaces as well as the response toward DA was recovered close to the original performance level after cleaning the surfaces for 10-20 cycles in H2SO4 on all materials but pyrolytic carbon (PyC). The recovery capacity of the PyC electrode was lower, possibly due to stronger adsorption of DA on the surface
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Observing wind, aerosol particles, clouds and precipitation: Finland's new ground-based remote-sensing network
The Finnish Meteorological Institute, in collaboration with the University of Helsinki, has established a new ground-based remote-sensing network in Finland. The network consists of five topographically, ecologically and climatically different sites distributed from southern to northern Finland. The main goal of the network is to monitor air pollution and boundary layer properties in near real time, with a Doppler lidar and ceilometer at each site. In addition to these operational tasks, two sites are members of the Aerosols, Clouds and Trace gases Research InfraStructure Network (ACTRIS); a Ka band cloud radar at Sodankylä will provide cloud retrievals within CloudNet, and a multi-wavelength Raman lidar, PollyXT (POrtabLe Lidar sYstem eXTended), in Kuopio provides optical and microphysical aerosol properties through EARLINET (the European Aerosol Research Lidar Network). Three C-band weather radars are located in the Helsinki metropolitan area and are deployed for operational and research applications. We performed two inter-comparison campaigns to investigate the Doppler lidar performance, compare the backscatter signal and wind profiles, and to optimize the lidar sensitivity through adjusting the telescope focus length and data-integration time to ensure sufficient signal-to-noise ratio (SNR) in low-aerosol-content environments. In terms of statistical characterization, the wind-profile comparison showed good agreement between different lidars. Initially, there was a discrepancy in the SNR and attenuated backscatter coefficient profiles which arose from an incorrectly reported telescope focus setting from one instrument, together with the need to calibrate. After diagnosing the true telescope focus length, calculating a new attenuated backscatter coefficient profile with the new telescope function and taking into account calibration, the resulting attenuated backscatter profiles all showed good agreement with each other. It was thought that harsh Finnish winters could pose problems, but, due to the built-in heating systems, low ambient temperatures had no, or only a minor, impact on the lidar operation – including scanning-head motion. However, accumulation of snow and ice on the lens has been observed, which can lead to the formation of a water/ice layer thus attenuating the signal inconsistently. Thus, care must be taken to ensure continuous snow removal
Atmospheric constraints on the methane emissions from the East Siberian Shelf
Subsea permafrost and hydrates in the East Siberian Arctic Shelf (ESAS) constitute a substantial carbon pool, and a potentially large
source of methane to the atmosphere. Previous studies based on interpolated
oceanographic campaigns estimated atmospheric emissions from this area at
8–17 TgCH<sub>4</sub> yr<sup>−1</sup>. Here, we propose insights based on atmospheric
observations to evaluate these estimates. The comparison of high-resolution
simulations of atmospheric methane mole fractions to continuous methane
observations during the whole year 2012 confirms the high variability and
heterogeneity of the methane releases from ESAS. A reference scenario with
ESAS emissions of 8 TgCH<sub>4</sub> yr<sup>−1</sup>, in the lower part of previously
estimated emissions, is found to largely overestimate atmospheric
observations in winter, likely related to overestimated methane leakage
through sea ice. In contrast, in summer, simulations are more consistent
with observations. Based on a comprehensive statistical analysis of the
observations and of the simulations, annual methane emissions from ESAS are
estimated to range from 0.0 to 4.5 TgCH<sub>4</sub> yr<sup>−1</sup>. Isotopic observations
suggest a biogenic origin (either terrestrial or marine) of the methane in
air masses originating from ESAS during late summer 2008 and 2009
Methane budget estimates in Finland from the CarbonTracker Europe-CH4 data assimilation system
This is the final version. Available from the publisher via the DOI in this record.We estimated the CH4 budget in Finland for 2004–2014 using the CTE-CH4 data assimilation system with an extended atmospheric CH4 observation network of seven sites from Finland to surrounding regions (Hyytiälä, Kjølnes, Kumpula, Pallas, Puijo, Sodankylä, and Utö). The estimated average annual total emission for Finland is 0.6 ± 0.5 Tg CH4 yr−1. Sensitivity experiments show that the posterior biospheric emission estimates for Finland are between 0.3 and 0.9 Tg CH4 yr−1, which lies between the LPX-Bern-DYPTOP (0.2 Tg CH4 yr−1) and LPJG-WHyMe (2.2 Tg CH4 yr−1) process-based model estimates. For anthropogenic emissions, we found that the EDGAR v4.2 FT2010 inventory (0.4 Tg CH4 yr−1) is likely to overestimate emissions in southernmost Finland, but the extent of overestimation and possible relocation of emissions are difficult to derive from the current observation network. The posterior emission estimates were especially reliant on prior information in central Finland. However, based on analysis of posterior atmospheric CH4, we found that the anthropogenic emission distribution based on a national inventory is more reliable than the one based on EDGAR v4.2 FT2010. The contribution of total emissions in Finland to global total emissions is only about 0.13%, and the derived total emissions in Finland showed no trend during 2004–2014. The model using optimized emissions was able to reproduce observed atmospheric CH4 at the sites in Finland and surrounding regions fairly well (correlation > 0.75, bias < ± ppb), supporting adequacy of the observations to be used in atmospheric inversion studies. In addition to global budget estimates, we found that CTE-CH4 is also applicable for regional budget estimates, where small scale (1x1 in this case) optimization is possible with a dense observation network.Natural Environment Research Council (NERC)NordFrosk Nordic Centre of ExcellenceAcademy of FinlandEuropean Research Council (ERC)Swiss National Science Foundation (SNSF)Swedish Research Counci
Measurement of electroweak WZ boson production and search for new physics in WZ plus two jets events in pp collisions at root s=13 TeV
A measurement of WZ electroweak (EW) vector boson scattering is presented. The measurement is performed in the leptonic decay modes WZ -> l nu l'l', where l, l' = e, mu. The analysis is based on a data sample of proton-proton collisions at root s = 13 TeV at the LHC collected with the CMS detector and corresponding to an integrated luminosity of 35.9 fb(-1) . The WZ plus two jet production cross section is measured in fiducial regions with enhanced contributions from EW production and found to be consistent with standard model predictions. The EW WZ production in association with two jets is measured with an observed (expected) significance of 2.2 (2.5) standard deviations. Constraints on charged Higgs boson production and on anomalous quartic gauge couplings in terms of dimension-eight effective field theory operators are also presented. (C) 2019 The Author(s). Published by Elsevier B.V.Peer reviewe
Search for additional neutral MSSM Higgs bosons in the tau tau final state in proton-proton collisions at root s=13 TeV
A search is presented for additional neutral Higgs bosons in the tau tau final state in proton-proton collisions at the LHC. The search is performed in the context of the minimal supersymmetric extension of the standard model (MSSM), using the data collected with the CMS detector in 2016 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1). To enhance the sensitivity to neutral MSSM Higgs bosons, the search includes production of the Higgs boson in association with b quarks. No significant deviation above the expected background is observed. Model-independent limits at 95% confidence level (CL) are set on the product of the branching fraction for the decay into tau leptons and the cross section for the production via gluon fusion or in association with b quarks. These limits range from 18 pb at 90 GeV to 3.5 fb at 3.2 TeV for gluon fusion and from 15 pb (at 90 GeV) to 2.5 fb (at 3.2TeV) for production in association with b quarks, assuming a narrow width resonance. In the m(h)(mod+) scenario these limits translate into a 95% CL exclusion of tan beta > 6 for neutral Higgs boson masses below 250 GeV, where tan beta is the ratio of the vacuum expectation values of the neutral components of the two Higgs doublets. The 95% CL exclusion contour reaches 1.6TeV for tan beta = 60.Peer reviewe
Search for resonant t(t)over-bar production in proton-proton collisions at root s=13 TeV
A search for a heavy resonance decaying into a top quark and antiquark (tt) pair is performed using proton-proton collisions at p s = 13TeV. The search uses the data set collected with the CMS detector in 2016, which corresponds to an integrated luminosity of 35.9 fb. The analysis considers three exclusive fi nal states and uses reconstruction techniques that are optimized for top quarks with high Lorentz boosts, which requires the use of nonisolated leptons and jet substructure techniques. No signi fi cant excess of events relative to the expected yield from standard model processes is observed. Upper limits on the production cross section of heavy resonances decaying to a tt pair are calculated. Limits are derived for a leptophobic topcolor Z 0 resonance with widths of 1, 10, and 30%, relative to the mass of the resonance, and exclude masses up to 3.80, 5.25, and 6.65TeV, respectively. Kaluza-Klein excitations of the gluon in the Randall-Sundrum model are excluded up to 4.55TeV. To date, these are the most stringent limits on tt resonances.Peer reviewe
Measurement of the energy density as a function of pseudorapidity in proton-proton collisions at root s=13 TeV
A measurement of the energy density in proton-proton collisions at a centre-of-mass energy of sTeV is presented. The data have been recorded with the CMS experiment at the LHC during low luminosity operations in 2015. The energy density is studied as a function of pseudorapidity in the ranges -6.6<<-5.2 and 3.15<||<5.20. The results are compared with the predictions of several models. All the models considered suggest a different shape of the pseudorapidity dependence compared to that observed in the data. A comparison with LHC proton-proton collision data at s=0.9 and 7 TeV confirms the compatibility of the data with the hypothesis of limiting fragmentation.Peer reviewe
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