519 research outputs found
Nonlinear Peculiar-Velocity Analysis and PCA
We allow for nonlinear effects in the likelihood analysis of peculiar
velocities, and obtain ~35%-lower values for the cosmological density parameter
and for the amplitude of mass-density fluctuations. The power spectrum in the
linear regime is assumed to be of the flat LCDM model (h=0.65, n=1) with only
Om_m free. Since the likelihood is driven by the nonlinear regime, we "break"
the power spectrum at k_b=0.2 h/Mpc and fit a two-parameter power-law at k>k_b.
This allows for an unbiased fit in the linear regime. Tests using improved mock
catalogs demonstrate a reduced bias and a better fit. We find for the Mark III
and SFI data Om_m=0.35+-0.09$ with sigma_8*Om_m^0.6=0.55+-0.10 (90% errors).
When allowing deviations from \lcdm, we find an indication for a wiggle in the
power spectrum in the form of an excess near k~0.05 and a deficiency at k~0.1
h/Mpc --- a "cold flow" which may be related to a feature indicated from
redshift surveys and the second peak in the CMB anisotropy. A chi^2 test
applied to principal modes demonstrates that the nonlinear procedure improves
the goodness of fit. The Principal Component Analysis (PCA) helps identifying
spatial features of the data and fine-tuning the theoretical and error models.
We address the potential for optimal data compression using PCA.Comment: 15 pages, LaTex, in Mining the Sky, July 31 - August 4, 2000,
Garching, German
Cosmological Density and Power Spectrum from Peculiar Velocities: Nonlinear Corrections and PCA
We allow for nonlinear effects in the likelihood analysis of galaxy peculiar
velocities, and obtain ~35%-lower values for the cosmological density parameter
Om and the amplitude of mass-density fluctuations. The power spectrum in the
linear regime is assumed to be a flat LCDM model (h=0.65, n=1, COBE) with only
Om as a free parameter. Since the likelihood is driven by the nonlinear regime,
we "break" the power spectrum at k_b=0.2 h/Mpc and fit a power law at k>k_b.
This allows for independent matching of the nonlinear behavior and an unbiased
fit in the linear regime. The analysis assumes Gaussian fluctuations and
errors, and a linear relation between velocity and density. Tests using proper
mock catalogs demonstrate a reduced bias and a better fit. We find for the
Mark3 and SFI data Om_m=0.32+-0.06 and 0.37+-0.09 respectively, with
sigma_8*Om^0.6 = 0.49+-0.06 and 0.63+-0.08, in agreement with constraints from
other data. The quoted 90% errors include cosmic variance. The improvement in
likelihood due to the nonlinear correction is very significant for Mark3 and
moderately so for SFI. When allowing deviations from LCDM, we find an
indication for a wiggle in the power spectrum: an excess near k=0.05 and a
deficiency at k=0.1 (cold flow). This may be related to the wiggle seen in the
power spectrum from redshift surveys and the second peak in the CMB anisotropy.
A chi^2 test applied to modes of a Principal Component Analysis (PCA) shows
that the nonlinear procedure improves the goodness of fit and reduces a spatial
gradient of concern in the linear analysis. The PCA allows addressing spatial
features of the data and fine-tuning the theoretical and error models. It shows
that the models used are appropriate for the cosmological parameter estimation
performed. We address the potential for optimal data compression using PCA.Comment: 18 pages, LaTex, uses emulateapj.sty, ApJ in press (August 10, 2001),
improvements to text and figures, updated reference
Associative3D: Volumetric Reconstruction from Sparse Views
This paper studies the problem of 3D volumetric reconstruction from two views
of a scene with an unknown camera. While seemingly easy for humans, this
problem poses many challenges for computers since it requires simultaneously
reconstructing objects in the two views while also figuring out their
relationship. We propose a new approach that estimates reconstructions,
distributions over the camera/object and camera/camera transformations, as well
as an inter-view object affinity matrix. This information is then jointly
reasoned over to produce the most likely explanation of the scene. We train and
test our approach on a dataset of indoor scenes, and rigorously evaluate the
merits of our joint reasoning approach. Our experiments show that it is able to
recover reasonable scenes from sparse views, while the problem is still
challenging. Project site: https://jasonqsy.github.io/Associative3DComment: ECCV 202
Standardization of Caco-2 cell culture as in vitro model for intestinal permeability
The aim of this study was to find out the optimal experimental conditions for Caco-2 cell culture
(time and density) and permeability assays (diffusion system and drug concentration) in order to
study the in vitro drugs permeability as a predictive method for drug absorption across intestinal epithelium.
The integrity of the monolayers used in each assay was determined by measuring the transepithelial
electrical resistance (TEER) and the permeability of the atenolol-a drug which is transported across the
monolayers by the paracellular pathway-. The best working condition was obtained with a cell seeding of
7.104 cells/insert in a vertical difussion chamber. In such context, the monolayers had a TEER higher than
550 Ω.cm2 and the apparent permeability coefficient of atenolol was 0.71 ± 0.19 x 10-6 cm/seg.Colegio de Farmacéuticos de la Provincia de Buenos Aire
A finite model of two-dimensional ideal hydrodynamics
A finite-dimensional su() Lie algebra equation is discussed that in the
infinite limit (giving the area preserving diffeomorphism group) tends to
the two-dimensional, inviscid vorticity equation on the torus. The equation is
numerically integrated, for various values of , and the time evolution of an
(interpolated) stream function is compared with that obtained from a simple
mode truncation of the continuum equation. The time averaged vorticity moments
and correlation functions are compared with canonical ensemble averages.Comment: (25 p., 7 figures, not included. MUTP/92/1
Clinical characteristics of vulnerable populations hospitalized and diagnosed with COVID-19 in Buenos Aires, Argentina
There is not in Argentina publications regarding the presentation of patients with COVID-19 requiring hospitalized and emergency care in vulnerable populations (lower incomes and less education tend at greater risk for poor health status and healthcare access), and it has few reports in developing countries. The objective is to determine whether in the care of vulnerable patients, to succeed against COVID-19, multiple public health tools and interventions will be needed to minimize morbidity and mortality. The study is a prospective cohort investigation of patients with lab-confirmed COVID-19, who required to any of the Health Centers response from April 8, 2020, to August 18, 2020. In Buenos Aires Metropolitan Area (AMBA), April 8, 2020 the virus was identified in patients hospitalized in the "Southeast Network" (SN), AMBA. SN covering an area of 661 square kilometers, with 1.8 million inhabitants residing in urban, and rural areas. A total of 14 health centers with different levels of care complexity provide care to patients in the region. The information of each patient with COVID-19 evaluated by SN, was incorporated in an Epidemiological Dashboard. The investigation was designed and reported with consideration of observational studies in epidemiology. We describe the hospitals presentation and care of persons who required SN response and were ultimately diagnosed with COVID-19. From April 8, 2020, to August 18, 2020, were included 1495 patients with lab-confirmed COVID-19 in SN. A total of 58% patients were men, and the mean age (SD) was 48.9 (15.59) years. Eighty one percent patients with pre-existing diseases, most frequent hypertension and diabetes, but hypertension, chronic lung disease, and cardiovascular disease presented higher risk. A total of 13% were hospitalized in Intensive Therapy Unit. The mortality of the cohort was 9.77%. Mortality was higher for patients aged 65 or more (OR 5.09), and for those had some pre-existing disease (OR 2.61). Our observations are consistent with reports demonstrating older persons, and those with comorbidities have the highest risk of mortality related to COVID-19. However, unlike other reports from developed or some developing countries, the mortality in our study is lower. This finding may be related to age of our cohort is younger than other published. Also, the health system was able to respond to the demand.Fil: Yacobitti, A.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. NĂ©stor Carlos Kirchner Samic; ArgentinaFil: Otero, L.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. NĂ©stor Carlos Kirchner Samic; ArgentinaFil: Doldan Arrubarrena, V.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. NĂ©stor Carlos Kirchner Samic; ArgentinaFil: Arano, J.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. NĂ©stor Carlos Kirchner Samic; ArgentinaFil: Lage, S.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. NĂ©stor Carlos Kirchner Samic; ArgentinaFil: Silberman, M.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. NĂ©stor Carlos Kirchner Samic; ArgentinaFil: Zubieta, M.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. NĂ©stor Carlos Kirchner Samic; ArgentinaFil: Erbetta, I.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. NĂ©stor Carlos Kirchner Samic; ArgentinaFil: Danei, P.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. NĂ©stor Carlos Kirchner Samic; ArgentinaFil: Baeck, G.. Hospital Mi Pueblo; ArgentinaFil: Vallejos, V.. No especifĂca;Fil: Cavalli, F.. No especifĂca;Fil: CalderĂłn, N.. Gobierno de la Provincia de Buenos Aires. Hospital Zonal General de Agudos Doctor Lucio Melendez.; ArgentinaFil: Di Gregorio, M.. Gobierno de la Provincia de Buenos Aires. Hospital Zonal General de Agudos Doctor Lucio Melendez.; ArgentinaFil: Hernandez, V.. Hospital Dr. Arturo Oñativia - Salta Capital.; ArgentinaFil: Bruno, D.. Hospital Dr. Arturo Oñativia - Salta Capital.; ArgentinaFil: Rodera, B.. Municipalidad de Quilmes (buenos Aires). Hospital Zonal General de Agudos Doctor Isidoro Iriarte.; ArgentinaFil: Macherett, I.. Municipalidad de Quilmes (buenos Aires). Hospital Zonal General de Agudos Doctor Isidoro Iriarte.; ArgentinaFil: Parisi, M.. Municipalidad de Quilmes (buenos Aires). Hospital Zonal General de Agudos Doctor Isidoro Iriarte.; ArgentinaFil: Gallastegui, M.. Municipalidad de Quilmes (buenos Aires). Hospital Zonal General de Agudos Doctor Isidoro Iriarte.; ArgentinaFil: Paz, A.. Municipalidad de Quilmes (buenos Aires). Hospital Sub Zonal Materno Infantil Doctor Eduardo Oller.; ArgentinaFil: Bernardi, R.. No especifĂca;Fil: Azcárate, S.. Gobierno de la Provincia de Buenos Aires. Hospital Provincial Evita Pueblo.; ArgentinaFil: Hraste, A.. Gobierno de la Provincia de Buenos Aires. Hospital Provincial Evita Pueblo.; ArgentinaFil: Caridi, DĂ©lida InĂ©s. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Cálculo; ArgentinaFil: Boechi, Leonardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Cálculo; ArgentinaFil: Salgado, P.. Universidad de Buenos Aires. Rectorado. Instituto de Investigaciones en Salud PĂşblica; ArgentinaFil: Kochen, Sara Silvia. Gobierno de la Provincia de Buenos Aires. Hospital de Alta Complejidad Cuenca Alta Doctor Nestor Carlos Kirchner.; Argentina. Universidad Nacional Arturo Jauretche; Argentina. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
Hydraulics of skimming flows on stepped chutes: The effects of inflow conditions?
Modern stepped spillways are typically designed for large discharge capacities corresponding to a skimming flow regime for which flow resistance is predominantly form drag. The writer demonstrates that the inflow conditions have some effect on the skimming flow properties. Boundary layer calculations show that the flow properties at inception of free-surface aeration are substantially different with pressurized intake. The re-analysis of experimental results highlights that the equivalent Darcy friction factor is f similar to 0.2 in average on uncontrolled stepped Chute and f similar to 0.1 on stepped chute with pressurized intake. A simple design chart is presented to estimate the residual flow velocity, and the agreement of the calculations with experimental results is deemed satisfactory for preliminary design
History of climate modeling
The history of climate modeling begins with conceptual models, followed in the 19th century by mathematical models of energy balance and radiative transfer, as well as simple analog models. Since the 1950s, the principal tools of climate science have been computer simulation models of the global general circulation. From the 1990s to the present, a trend toward increasingly comprehensive coupled models of the entire climate system has dominated the field. Climate model evaluation and intercomparison is changing modeling into a more standardized, modular process, presenting the potential for unifying research and operational aspects of climate science. WIREs Clim Change 2011 2 128–139 DOI: 10.1002/wcc.95 For further resources related to this article, please visit the WIREs websitePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79438/1/95_ftp.pd
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