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Lange D.,Polytechnic University of Catalonia | Lange D.,Institute Destudis Espacials Of Catalonia | Rocadenbosch F.,Polytechnic University of Catalonia | Rocadenbosch F.,Institute Destudis Espacials Of Catalonia | And 2 more authors.
IEEE Transactions on Geoscience and Remote Sensing | Year: 2015

An adaptive solution based on an extended Kalman filter (EKF) is proposed to estimate the atmospheric boundary-layer height (ABLH) from frequency-modulated continuous-wave S-band weather-radar returns. The EKF estimator departs from previous works, in which the transition interface between the mixing layer (ML) and the free troposphere (FT) is modeled by means of an erf-like parametric function. In contrast to lidar remote sensing, where aerosols give strong backscatter returns over the whole ML, clear-air radar reflectivity returns (Bragg scattering from refractive turbulence) shows strongest returns from the ML-FT interface. In addition, they are corrupted by 'insect' noise (impulsive noise associated with Rayleigh scattering from insects and birds), all of which requires a specific treatment of the problem and the measurement noise for the clear-air radar case. The proposed radar-ABLH estimation method uses: 1) a first preprocessing of the reflectivity returns based on median filtering and threshold-limited decision to obtain 'clean' reflectivity signal; 2) a modified EKF with adaptive range intervals as time tracking estimator; and 3) ad hoc modeling of the observation noise covariance. The method has successfully been implemented in clear-air, single-layer, and convective boundary-layer conditions. ABLH estimates from the proposed radar-EKF method have been cross examined with those from a collocated lidar ceilometer yielding a correlation coefficient as high as ρ=0.93 (mean signal-to-noise ratio, SNR = 18 (linear units), at the ABLH) and in relation to the classic THM. © 2014 IEEE. Source

del Favero J.M.,University of Sao Paulo | Katsuragawa M.,University of Sao Paulo | Zani-Teixeira M.L.,University of Sao Paulo | Turner J.T.,University of Massachussets
Brazilian Journal of Oceanography | Year: 2015

Studies of ichthyoplankton retention by nets of different mesh sizes are important because they help in choosing a sampler when planning collection and the establishment of correction factors. These factors make it possible to compare studies performed with nets of different mesh sizes. In most studies of mesh retention of fish eggs, the taxonomic identification is done at the family level, resulting in the loss of detailed information. We separated Engraulidae eggs, obtained with 0.333 mm and 0.505 mm mesh bongo nets at 172 oceanographic stations in the southeastern Brazilian Bight, into four groups based on their morphometric characteristics. The difference in the abundance of eggs caught by the two nets was not significant for those groups with highest volume, types A and B, but in type C (Engraulis anchoita), the most eccentric, and in type D, of the smallest volume, the difference was significant. However, no significant difference was observed in the egg size sampled with each net for E. anchoita and type D, which exhibited higher abundance in the 0.333 mm mesh net and minor axis varying from 0.45-0.71 mm, smaller than the 0.505 mm mesh aperture and the mesh diagonal. © 2015, Universidade de Sao Paulo. All rights reserved. Source

Nichter M.,University of Arizona | Carkoglu A.,Dogus University | Lloyd-Richardson E.,University of Massachussets
Drug and Alcohol Dependence | Year: 2010

Background: This paper reports on qualitative research on smoking in contexts associated with drinking among college students. Although a plethora of survey research has shown a positive association between smoking and alcohol use, little attention has been given to the utility functions of these co-occurring behaviors. Methods: Data are drawn from semi-structured interviews with college freshmen at a large Mid-western university in the U.S. (n = 35). In addition, eleven focus groups with fraternity and sorority members were conducted (n = 70). Interviews and focus groups focused on a range of issues including current smoking behavior, reasons for smoking, and smoking and drinking. Results: A review of qualitative responses reveals that smoking served multiple utility functions for this population including (1) facilitating social interaction across gender, (2) allowing one to structure time and space at a party, (3) enabling "party" smokers to smoke with fewer negative side effects, and (4) helping to calm one down when drunk. Conclusions: Whereas smoking was stigmatized during the context of one's everyday life as a student, at parties while consuming alcohol, smoking was viewed as normative and socially acceptable. Preventive interventions are needed on college campus that target co-substance use and address widespread misperceptions about the harm of tobacco use and addiction. Source

More S.,Max Planck Institute for Astronomy | More S.,University of Chicago | Van Den Bosch F.C.,Max Planck Institute for Astronomy | Van Den Bosch F.C.,University of Utah | And 6 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2011

We use the kinematics of satellite galaxies that orbit around the central galaxy in a dark matter halo to infer the scaling relations between halo mass and central galaxy properties. Using galaxies from the Sloan Digital Sky Survey, we investigate the halo mass-luminosity relation (MLR) and the halo mass-stellar mass relation (MSR) of central galaxies. In particular, we focus on the dependence of these scaling relations on the colour of the central galaxy. We find that red central galaxies on average occupy more massive haloes than blue central galaxies of the same luminosity. However, at fixed stellar mass there is no appreciable difference in the average halo mass of red and blue centrals, especially for M*≲ 1010.5 h-2 Mȯ. This indicates that stellar mass is a better indicator of halo mass than luminosity. Nevertheless, we find that the scatter in halo masses at fixed stellar mass is non-negligible for both red and blue centrals. It increases as a function of stellar mass for red centrals but shows a fairly constant behaviour for blue centrals. We compare the scaling relations obtained in this paper with results from other independent studies of satellite kinematics, with results from a SDSS galaxy group catalog, from galaxy-galaxy weak lensing measurements and from subhalo abundance matching studies. Overall, these different techniques yield MLRs and MSRs in fairly good agreement with each other (typically within a factor of 2), indicating that we are converging on an accurate and reliable description of the galaxy-dark matter connection. We briefly discuss some of the remaining discrepancies among the various methods. © 2010 The Authors. Journal compilation © 2010 RAS. Source

Stocchi P.,Netherlands Institute for Sea Research | Stocchi P.,University Utrecht | Escutia C.,Instituto Andaluz Of Ciencias Of La Tierra | Houben A.J.P.,University Utrecht | And 41 more authors.
Nature Geoscience | Year: 2013

During the middle and late Eocene (∼48-34 Myr ago), the Earth's climate cooled1,2 and an ice sheet built up on Antarctica. The stepwise expansion of ice on Antarctica3,4induced crustal deformation and gravitational perturbations around the continent. Close to the ice sheet, sea level rose5,6despite an overall reduction in the mass of the ocean caused by the transfer of water to the ice sheet. Here we identify the crustal response to ice-sheet growth by forcing a glacial-hydro isostatic adjustment model7 with an Antarctic ice-sheet model. We find that the shelf areas around East Antarctica first shoaled as upper mantle material upwelled and a peripheral forebulge developed. The inner shelf subsequently subsided as lithosphere flexure extended outwards from the ice-sheet margins. Consequently the coasts experienced a progressive relative sea-level rise. Our analysis of sediment cores from the vicinity of the Antarctic ice sheet are in agreement with the spatial patterns of relative sea-level change indicated by our simulations. Our results are consistent with the suggestion8 that near-field processes such as local sea-level change influence the equilibrium state obtained by an icesheet grounding line. Source

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