965 research outputs found

    Brightness temperature and attenuation diversity statistics at 20.6 and 31.65 GHz for the Colorado Research Network

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    A limited network of four dual-channel microwave radiometers, with frequencies of 20.6 and 31.65 GHz, was operated in the front range of eastern Colorado from 1985 to 1988. Data, from November 1987 through October 1988 are analyzed to determine both single-station and joint-station brightness temperature and attenuation statistics. Only zenith observations were made. The spatial separations of the stations varied from 50 km to 190 km. Before the statistics were developed, the data were screened by rigorous quality control methods. One such method, that of 20.6 vs. 31.65 GHz scatter plots, is analyzed in detail, and comparisons are made of measured vs calculated data. At 20.6 and 31.65 GHz, vertical attenuations of 5 and 8 dB are exceeded 0.01 percent of the time. For these four stations and at the same 0.01 percent level, diversity gains from 6 to 8 dB are possible with the 50 to 190 km separations

    Generalized Conditional Gradient with Augmented Lagrangian for Composite Minimization

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    In this paper we propose a splitting scheme which hybridizes generalized conditional gradient with a prox-imal step which we call CGALP algorithm, for minimizing the sum of three proper convex and lower-semicontinuous functions in real Hilbert spaces. The minimization is subject to an affine constraint, that allows in particular to deal with composite problems (sum of more than three functions) in a separate way by the usual product space technique. While classical conditional gradient methods require Lipschitz-continuity of the gradient of the differentiable part of the objective, CGALP needs only differentiability (on an appropriate subset), hence circumventing the intricate question of Lipschitz continuity of gradients. For the two remaining functions in the objective, we do not require any additional regularity assumption. The second function, possibly nonsmooth, is assumed simple, i.e., the associated proximal mapping is easily computable. For the third function, again nonsmooth, we just assume that its domain is weakly compact and that a linearly perturbed minimization oracle is accessible. In particular, this last function can be chosen to be the indicator of a nonempty bounded closed convex set, in order to deal with additional constraints. Finally, the affine constraint is addressed by the augmented Lagrangian approach. Our analysis is carried out for a wide choice of algorithm parameters satisfying so called "open loop" rules. As main results, under mild conditions, we show asymptotic feasibility with respect to the affine constraint, boundedness of the dual multipliers, and convergence of the Lagrangian values to the saddle-point optimal value. We also provide (subsequential) rates of convergence for both the feasibility gap and the Lagrangian values.Dans ce travail, nous proposons un schéma d’éclatement en optimisation non lisse, hybridant le gradient conditionnel avec une étapeproximale que nous appelons CGALP , pour minimiser la somme de fonctions propres fermées et convexes sur un compact de R n . La minimisationest de plus sujette à une contrainte affine, que nous prenons en compte par un Lagrangien augmenté, en qui permet en particulier de traiter desproblèmes composites à plusieurs fonctions par une technique d’espace produit. Certaines fonctions sont autorisées à être non lisses mais dontl’opérateur proximal est simple à calculer. Notre analyse et garanties de convergence sont assurées pour un large choix de paramètres "en boucleouverte". Comme résultats principaux, nous montrons la faisabilité asymptotique de la variable primale, la convergence de toute sous-suite versune solution du problème primal, la convergence de la variable duale à une solution du problème dual, et la convergence du Lagrangien. Des tauxde convergence sont aussi fournis. Les implications et illustrations de l’algorithme en traitement des données sont discutées

    Brightness temperature and attenuation statistics at 20.6 and 31.65 GHz

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    Attenuation and brightness temperature statistics at 20.6 and 31.65 GHz are analyzed for a year's worth of data. The data were collected in 1988 at Denver and Platteville, Colorado. The locations are separated by 49 km. Single-station statistics are derived for the entire year. Quality control procedures are discussed and examples of their application are given

    Gradient conditionnel généralisé et lagrangien augmenté pour la minimisation composite

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    National audienceDans ce travail, nous proposons un schéma d'éclatement en optimisation non lisse, hybridant le gradient conditionnel avec une étape proximale que nous appelons CGALP, pour minimiser la somme de fonctions propres fermées et convexes sur un compact de Rn\mathbb{R}^n. La minimisation est de plus sujette à une contrainte affine, que nous prenons en compte par un Lagrangien augmenté, en qui permet en particulier de traiter des problèmes composites à plusieurs fonctions par une technique d'espace produit. Certaines fonctions sont autorisées à être non lisses mais dont l'opérateur proximal est simple à calculer. Notre analyse et garanties de convergence sont assurées pour un large choix de paramètres en boucle ouverte. Comme résultats principaux, nous montrons la faisabilité asymptotique de la variable primale, la convergence de toute sous-suite vers une solution du problème primal, la convergence de la variable duale à une solution du problème dual, et la convergence du Lagrangien. Des taux de convergence sont aussi fournis. Les implications et illustrations de l'algorithme en traitement des données sont discutées

    Highly resolved WRF-BEP/BEM simulations over Barcelona urban area with LCZ

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    Unidad de excelencia María de Maeztu CEX2019-000940-MThis study evaluates the performance of urban schemes integrated in the Weather Research and Forecasting model (WRF) using Local Climate Zones (LCZ) as land use classification. We applied two multi-layer urban schemes: 1) Building Effect Parameterization (BEP) and 2) Building Energy Model coupled with BEP (BEP + BEM), over the Metropolitan Area of Barcelona (MAB) at 1km2 horizontal resolution for July 2016. These two simulations were compared with observations and a standard WRF simulation (BULK approach). Corine Land Cover 2012 provides background information for the entire simulation domain, while the LCZ covers MAB classifying the land cover into 10 classes according to urban morphology and thermal properties. BULK and multi-layer urban scheme experiments present a similar general error trend: overestimation of relative humidity and planetary boundary layer height and underestimation of temperature. Although BEP has the best correlation with observations, this is the scheme with the highest value of bias and RMSE for temperature and relative humidity, in particular during the night/morning. On the other hand, BEP + BEM performed with the minimum RMSE associated for temperature and relative humidity in the entire domain. BEP + BEM has shown to be more sensitive than the other schemes over locations where the land use in the model grid differs to the real one, which is a common consequent limitation of horizontal model resolution. This study also suggests that depending on the synoptic condition the scheme accuracy on determining PBLH might change considerably

    Carbon nanopipettes for cell probes and intracellular injection

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    We developed integrated, carbon-based pipettes with nanoscale dimensions (CNP) that can probe cells with minimal intrusion, inject fluids into the cells, and concurrently carry out electrical measurements. Our manufacturing technique does not require cumbersome nanoassembly and is amenable to mass production. Using CNPs, we demonstrate the injection of reagents into cells with minimal intrusion and without inhibiting cell growth

    Enhancement of vaccinia virus based oncolysis with histone deacetylase inhibitors

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    Histone deacetylase inhibitors (HDI) dampen cellular innate immune response by decreasing interferon production and have been shown to increase the growth of vesicular stomatitis virus and HSV. As attenuated tumour-selective oncolytic vaccinia viruses (VV) are already undergoing clinical evaluation, the goal of this study is to determine whether HDI can also enhance the potency of these poxviruses in infection-resistant cancer cell lines. Multiple HDIs were tested and Trichostatin A (TSA) was found to potently enhance the spread and replication of a tumour selective vaccinia virus in several infection-resistant cancer cell lines. TSA significantly decreased the number of lung metastases in a syngeneic B16F10LacZ lung metastasis model yet did not increase the replication of vaccinia in normal tissues. The combination of TSA and VV increased survival of mice harbouring human HCT116 colon tumour xenografts as compared to mice treated with either agent alone. We conclude that TSA can selectively and effectively enhance the replication and spread of oncolytic vaccinia virus in cancer cells. © 2010 MacTavish et al

    Lesions of the Perirhinal Cortex but Not of the Frontal, Medial Prefrontal, Visual, or Insular Cortex Block Fear-Potentiated Startle Using a Visual Conditioned Stimulus

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    The present study is part of an ongoing series of experiments aimed at delineation of the neural pathways that mediate fear-potentiated startle, a model of conditioned fear in which the acoustic startle reflex is enhanced when elicited in the presence of a light previously paired with shock. A number of cortical areas that might be involved in relaying information about the visual conditioned stimulus (the light) in fear-potentiated startle were investigated. One hundred thirty-five rats were given 10 light-shock pairings on each of 2 consecutive days, and l-2 d later electrolytic or aspiration lesions in various cortical areas were performed. One week later, the magnitude of fear-potentiated startle was measured. Complete removal of the visual cortex, medial prefrontal cortex, insular cortex, or posterior perirhinal cortex had no significant effect on the magnitude of fear-potentiated startle. Lesions of the frontal cortex attenuated fear-potentiated startle by approximately 50%. However, lesions of the anterior perirhinal cortex completely eliminated fear-potentiated startle. The effective lesions included parts of the cortex both dorsal and ventral to the rhinal sulcus and extended from approximately 1.8 to 3.8 mm posterior to bregma. Lesions slightly more posterior (2.3-4.8 mm posterior to bregma) or lesions that included only the perirhinal cortex dorsal to the rhinal sulcus had no effect. The region of the perirhinal cortex in which lesions blocked fear-potentiated startle projects to the amygdala, and thus may be part of the pathway that relays the visual conditioned stimulus information to the amygdala, a structure that is also critical for fear-potentiated startle. In addition, the present findings are in agreement with numerous studies in primates suggesting that the perirhinal cortex may play a more general role in memory

    Lab-On-A-Chip for Oral Cancer Screening and Diagnosis

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    Oral squamous cell carcinoma (OSCC) is a disfiguring and deadly cancer. Despite advances in therapy, many patients continue to face a poor prognosis. Early detection is an important factor in determining the survival of patients with OSCC. No accurate, cost-efficient, and reproducible method exists to screen patients for OSCC. As a result, many patients are diagnosed at advanced stages of the disease. Early detection would identify patients, facilitating timely treatment and close monitoring. Mass screening requires a rapid oral cancer diagnostic test that can be used in a clinical setting. Current diagnostic techniques for OSCC require modern laboratory facilities, sophisticated equipment, and elaborate and lengthy processing by skilled personnel. The lab-on-chip technology holds the promise of replacing these techniques with miniaturized, integrated, automated, inexpensive diagnostic devices. This article describes lab-on-chip devices for biomarker-based identification of oral cancer. Similar methods can be employed for the screening of other types of cancers
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