321 research outputs found
Hardy type spaces on certain noncompact manifolds and applications
In this paper we consider a complete connected noncompact Riemannian manifold
M with Ricci curvature bounded from below, positive injectivity radius and
spectral gap b. We introduce a sequence X^1(M), X^2(M), ... of new Hardy spaces
on M, the sequence Y^1(M/, Y^2(M), ... of their dual spaces, and show that
these spaces may be used to obtain endpoint estimates for purely imaginary
powers of the Laplace-Beltrami operator and for more general spectral
multipliers associated to the Laplace--Beltrami operator L on M. Under the
additional condition that the volume of the geodesic balls of radius r is
controlled by C r^a e^{2\sqrt{b} r} for some real number a and for all large r,
we prove also an endpoint result for first order Riesz transforms D L^{-1/2}.
In particular, these results apply to Riemannian symmetric spaces of the
noncompact type.Comment: 27 pages, v2: the first version has been revised and rearranged, with
additions, in two papers, of which this new version is the first. The second
paper is posted as arXiv:1002.1161v
Continuous dependence of very weak solutions for the stationary Navier-Stokes equations
In this work we show the continuous dependence of the very weak solutions for the stationary Navier- tokes system with respect to boundary data belonging to space L2(T).
 
Evaluación de las condiciones de trabajo en fincas cafeteras del Departamento del Quindío (Colombia)
Farmers in the rural area of the department of Quindío (Colombia) base their economy on agricultural and livestock work. This activity is often an informal and temporary economy, with precarious working conditions that give rise to occupational accidents and/or diseases. The objective of this study is to identify the occupational risks to which farm workers are exposed in 82 farms located in 4 municipalities of the department of Quindío. The study is descriptive-observational and quantitative. The occupational risks of working conditions found in the research were: 100% of workers handle hazardous agrochemicals inadequately, 80% do not have occupational health and safety activities or emergency plans, 72% have a demand for physical activity outdoors due to long working hours, and 65% are exposed to biological agents due to mosquito bites and accidents, among others. This study showed that farmers are exposed to poorly controlled occupational risks and do not have comprehensive social security protection or occupational risk promotion and prevention activities to improve working conditions and therefore their life quality.Peer ReviewedObjectius de Desenvolupament Sostenible::3 - Salut i BenestarObjectius de Desenvolupament Sostenible::8 - Treball Decent i Creixement EconòmicPostprint (published version
An extended 3-3-1 model with radiative linear seesaw mechanism
Motivated by the recent muon anomalous magnetic moment (g-2) measurement at
FERMILAB and non-zero neutrino masses, we propose a model based on the (3-3-1) gauge symmetry. The most popular 3-3-1
models in the literature require the presence of a scalar sextet to address
neutrino masses. In our work, we show that we can successfully implement an
one-loop linear seesaw mechanism with right-handed neutrinos, and vector-like
fermions to nicely explain the active neutrino masses, and additionally
reproduce the recent Muon g-2 result, in agreement with existing bounds.Comment: 11 pages, 2 figure
IMPLEMENTATION OF PATTERN RECOGNITION TECHNIQUES (SUPPORT VECTOR MACHINES - LEAST SQUARE) IN SELECTION OF PARAMETERS USED IN METABOLOMIC SYSTEMS
En este artículo se presenta una metodologíaque involucra, técnicas de análisis multivariable y una etapa de pre-procesamiento con el fin de determinar metabolitos característicos en un determinado espectro. Este método novedoso permitió determinar que ciertos metabolitos son modificados por las diferentes concentraciones y además de conocer la funcionalidad de LS-SVM en datos NMR. También se logró validar procesos como: alineamiento de picos, normalización, corrección de línea base y análisis multienergía, en datos metabolómicos en aceites de oliva y avellana puros y mezclados con alteraciones de 2%, 5%, 10%, 20% y 30%.This paper presents a metodología que involved, multivariate analysis techniques and pre-processing stage in order to determine characteristic metabolites in agiven spectrum. This novel approach allowed us to determine that certain metabolites are modified by the addition of different concentrations of about feature SVM LS-NMR data. Validating processes also achieved as peak alignment, normalization, baseline correction and analysis multienergy in metabolomic data in olive oils and pure and mixed with hazelnut alterations 2%, 5%, 10%, 20% and 30
Lignanos diarildimetilbutanos y otros constituyentes aislados de Nectandra turbacensis (kunth) nees (lauraceae)
Ocho compuestos conocidos fueronaislados del extracto etanólico de cortezade Nectandra turbacensis (Kunth) Nees(Lauraceae). Estos fueron identificados comoácido meso-dihidroguayarético 1, ácidotreo-dihidroguayarético 2, sauriol B 3, ytreo-austrobailignano-6 4; vitexina (8-C-β-D-glucopiranosil-5,7,4’-trihidroxiflavona) 5;estigmast-4-en-3-ona 6 y la mezcla sitosterol7 / estigmasterol 8. Las estructuras de loscompuestos fueron elucidadas por métodosespectroscópicos, que incluyeron técnicas deRMN en 1D y 2D, CG/EM y por comparaciónde los datos espectroscópicos, reportadosen la literatura de compuestos relacionados.Este es el primer reporte de la presenciade este tipo de compuestos en la especie.Se describen también las implicacionesquimiotaxonómicas; relacionadas con lapresencia frecuente de lignanos en especiesdel género Nectandra
Encontro casual na região central do Texas fornece informações sobre a ecologia da estivação de Siren nettingi (Caudata: Sirenidae)
Siren spp. costumam ser vertebrados dominantes nas áreas úmidas que ocupam e são conhecidas por estivar quando essas áreas úmidas secam. Considerações práticas limitam as observações in situ de indivíduos em estivação. Em 12 de outubro de 2021, descobrimos por acaso um agregado em estivação de Siren nettingi no condado de Bastrop, Texas, Estados Unidos. Essas salamandras foram escavadas em solo compacto e rochoso adjacente a uma estrada de caliche, em profundidades que variavam entre ~0,2 e 1,5 m. A vegetação dominante nesse local incluía Ulmus crassifolia, Persicaria sp. e várias espécies de gramíneas. Recuperamos 140 indivíduos, dos quais sete foram resgatados e 133 foram capturados vivos. Medimos 115 deles quanto ao comprimento rostro-cloacal (SVL) e observamos que o agregado era dominado por jovens. Estimamos uma densidade de estivação de 2,33 indivíduos/m2 que é comparável às densidades estimadas para populações sem estivação. No entanto, como não houve monitoramento para esse estudo, provavelmente tenha ocorrido um evento de mortalidade em massa. Portanto, sugerimos que a construção de estradas no habitat preferido seja considerada uma ameaça às populações dessas salamandras.Siren spp. are often dominant vertebrates in the wetlands they occupy and are known to estivate when such wetlands dry up. Practical considerationslimit in-situ observations of estivating individuals. On 12 October 2021, we incidentally discovered an estivating aggregate of Siren nettingi in Bastrop County, Texas, USA. These salamanders were excavated from compact, rocky soil adjacent to a caliche road, at depths that ranged between ~0.2 to 1.5 m. The dominant vegetation at this site included Ulmus crassifolia, Persicaria sp., and various grass species. We recovered 140 individuals of which seven were salvaged and 133 were captured live. We measured 115 of these for snout–vent length (SVL) and observed the aggregate was predominated by juveniles. We estimated an estivation density of 2.33 sirens/m2 that is comparable to densities estimated for non-estivating populations. However, in-lieu of monitoring that was in place for this study, we expect a mass mortality event would have likely occurred. We therefore suggest that roadway construction in preferred habitat be considered as a threat to siren populations
A low-absorption disk zone at low Galactic latitude in Centaurus
We investigate the properties of two stellar concentrations in a
low-absorption disk zone in Centaurus, located respectively at
, , and , . The present analysis is based mostly on 2MASS photometry, as well as
optical photometry. Based on colour-magnitude diagrams and stellar radial
density profiles, we show that these concentrations are not open star clusters.
Instead, they appear to be field stars seen through a differentially-reddened
window. We estimate that the bulk of the stars in both stellar concentrations
is located at kpc from the Sun, a distance consistent with that of
the Sgr-Car arm in that direction. This low-absorption window allows one to
probe into distant parts of the disk besides the Sgr-Car arm, probably the
tangent part of the Sct-Cru arm, and/or the far side of the Sgr-Car arm in that
direction. The main sequence associated to the Sgr-Car arm is reddened by
\ebv\sim0.5, so that this window through the disk is comparable in reddening
to Baade's window to the bulge. We also investigate the nature of the open
cluster candidate Ru 166. The presently available data do not allow us to
conclude whether Ru 166 is an actual open cluster or field stars seen through a
small-scale low-absorption window
Caracterización del consumo de alimentos en familias desplazadas del municipio de Lebrija, Santander. Colombia. 2006
RESUMENOBJETIVOS: Caracterizar el consumo de alimentos en las familias desplazadas del municipio de Lebrija y describir la percepción que tienen con respecto a la inseguridad alimentaria. METODOLOGÍA: Durante 2004-2005, 61 familias desplazadas del municipio de Lebrija contestaron una encuesta para determinar el gasto mensual en alimentos y la frecuencia de compra. Se utilizó un recordatorio del consumo de alimentos en las últimas 24 horas. Para determinar la cantidad y tipo de alimentos consumidos se aplicó una encuesta sobre la percepción de la seguridad alimentaria. El proceso de los datos se realizó con SICI, Epi Info 6,04d y Stata STATA/SE v. 8,2. RESULTADOS: El ingreso promedio mensual de los hogares es de 0.67 SMMLV, en el 83,6% de las familias sólo trabaja un miembro. El 88,0% de las familias presenta inseguridad alimentaría leve y el 12,0% moderada. El 100% de las familias argumentó falta de dinero para comprar alimentos. El consumo de frutas y lácteos sólo cubre el 25,0% de las recomendaciones establecidas y el de verduras un 15,0%. CONCLUSIÓN: Las familias de este estudio muestran una proporción de Inseguridad Alimentaria mucho mayor a los estudios nacionales, esto es evidenciado en la defciente calidad de la dieta consecuente con el bajo ingreso y el desconocimiento de alternativas nutricionales. Palabras claves: Conducta alimentaria, seguridad alimentaria, comunidades vulnerables, dieta, Colombia. ABSTRACTOBJECTIVES: To characterize the intake of foods in the displaced families of the municipality of Lebrija and to describe the perception that they have regarding the food insecurity. METHODOLOGY: During 2004-2005, 61 displaced families of the municipality of Lebrija answered a survey to determine the monthly expense in foods and the purchase frequency. A recall of the consumption of foods in the last 24 hours was used. To determine the quantity and type of consumed foods was applied a survey about the perception of the food security. The process of the data was carried out with SICI, Epi Info 6.04d and STATA/SE v. 8.2. RESULTS: The entrance monthly average of the homes is of 0.67 SMMLV, in 83.6% of the families a member only works. 88.0% of the families presents insecurity it would feed light and 12.0 moderate%. 100% of the families argued lack of money to buy foods. The consumption of fruits and milky it only covers 25.0% of the established recommendations and that of vegetables 15.0%. CONCLUSION: The families of this study show a proportion of foods insecurity much bigger to the national studies, this is evidenced in the faulty quality of the consequent diet with the low income and the ignorance of alternative nutritional. Keywords: Alimentary pattern, alimentary insecurity, displacement, Colombia
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