1,280 research outputs found
¿Cuánto Dura el Desempleo para la Población más Pobre en Chile?
This paper analyzes the determinants of the unemployment spells for the beneficiaries of “Chile Solidario”, a conditional cash-transfer program. The evidence on unemployment spells for Chile is scarce. Employing the Kaplan- Mehier’s non-parametric estimatDesempleo, modelos de duración, pobreza
Anti-Crime Programs: An Evaluation of the Comuna Segura Program
The aim of this paper is to evaluate the impact that the anti-crime program Comuna Segura: Compromiso 100 had on the reporting rate of different types of crimes. This program, implemented in Chile starting in 2001, was very highly criticized and, therefore, was eliminated in 2006. This paper provides statistical evidence, using the impact assessment methodology, which shows that the program was successful in increasing the reporting rate in targeted municipalities and also in decreasing levels of crimes associated with other crimes, such as rape. All this underlies the importance of carrying out formal impact assessments in order to determine benefits that are associated with a particular program. However, financial issues are also very important too and it is necessary to take them in account when making a fair statement about the cost-effectiveness of the program. This point is, however, not addressed in this paper but should be kept in mind in order to have a complete picture of the program.Crime, Program evaluation, Matching.
Sotaiart: prácticas críticas en los intersticios de un museo
This article makes a relationship of the critical practices in museum with interstices though the example of a educational workshop called "sotai art" at the Fundació Pilar y Joan Miró at Palma de Mallorca. In uses an interdisciplinary approach from the frames of critical pedagogy, critical museology and the new shifts in art education with poststructuralism. This educative practice is then presented as a case of critical cultural policies within museum .This workshop will be developed from serialization of micro-processes as an infiltration of diverse gazes and cultures that finally constitutes a space of articulated micronarratives from the mixing of sotai and contemporary art The workshop is analysed as a in interstice, as a critical gap o in-between space if resistance within the museum domain, that explores and overdraws positively the blind spots of a museum, and simoultanesly makes flexible the structure and function of the museu
Obtaining the fatigue laws of bituminous mixtures from a strain sweep test: effect of temperature and aging
Fatigue is associated with the deterioration caused by applying repeated loads, and is affected by temperature or aging. Generally, time sweep tests are used to simulate fatigue, in order to obtain the fatigue laws. However, this requires too much time, often preventing its use. A method to estimate the fatigue laws from a strain sweep test is presented. The test was performed on a semi-dense mixture with different types of binder (unconditioned or aged) tested at different temperatures. This test is able to estimate fatigue laws more quickly, allowing the effect of different factors on the mixtures' fatigue life to be studied.Peer ReviewedPostprint (author's final draft
Complexity of the behaviour of asphalt materials in cyclic testing
This paper compares the results obtained in two types of cyclic tension-compression tests, a time sweep test, constant strain amplitude, and a strain sweep test, increasing strain amplitude every 5000 cycles, called EBADE (standing for the Spanish words for strain sweep test). This comparison has shown that the rapid loss of stiffness during the initial part of cyclic testing is recoverable in bituminous materials. It has been found that reversible phenomena dominate in asphalt binders, while in mixtures are as important as damage. A damage equation has been proposed to describe the evolution of the material distress during the phase II in time sweep tests. In addition, a new methodology to estimate the fatigue law of bituminous mixtures is proposed.Peer ReviewedPostprint (author's final draft
Ageing and temperature effect on the fatigue performance of bituminous mixtures
The ageing of asphalt mixes, together with their exposure to low temperatures, causes a progressive increase of cracking. In this paper, the effect of ageing and temperature on the fatigue of asphalt concretes made with two types of binders, conventional (50/70) and polymer modified bitumen (PMB), is studied. For this purpose, specimens previously subjected to an accelerated laboratory ageing process were tested by a strain sweep test at different temperatures (-5°C, 5°C and 20°C). Results were compared with the obtained from the unaged specimens showing the relative importance of ageing, temperature and type of bitumen on the parameters that determine the fatigue life of the mixture. The mixtures behaviour becomes more brittle with ageing and the decrease of temperature. However, ageing hardly has an effect on fatigue at lower temperatures. In general, mixtures made with polymer modified bitumen have a better fatigue performance to ageing and temperature.Peer ReviewedPostprint (published version
Evaluación de Subproductos de Cloración y su efecto mutagénico en agua para consumo humano
Proyecto de Investigación
Instituto Tecnológico de Costa Rica. Vicerrectoría de Investigación y Extensión (VIE). Escuela de Química. Centro de Investigación y de Servicios Químicos y Microbiológicos (CEQIATEC), Centro de Investigación en Protección Ambiental (CIPA), 2013Se investigó la presencia de subproductos de desinfección como trihalometanos (THMs) por medio de la técnica de microextracción en fase sólida (HEADSPACE / SPME Solid Fase Microextraction / GS-MS), utilizando un Cromatógrafo de Gases Varian 450 acoplado a Espectrómetro de Masas. Se analizaron en total 39 muestras de agua, provenientes de fuentes de agua subterránea (nacientes) administradas por la Municipalidad del Cantón Central de Cartago y agua de origen superficial (Plantas de tratamiento completo) dispensada por los sistemas de Tratamiento de AyA/Cantón Central de Cartago, y los Sistema de Tratamiento de AyA de Moravia, Guadalupe y Pavas, con un total de 156 subproductos determinados y cuantificados correspondiendo estos a: cloroformo, bromodiclorometano, dibromoclorometano y tribromoclorometano. En las muestras de agua de sistemas de tratamiento completo se encontró que de 80 subproductos analizados, 12 de estos superaron el máximo admisible de acuerdo al Reglamento Nacional de Calidad de Agua para consumo humano, mientras que de los acueductos abastecidos de aguas subterráneas administrados por la Municipalidad de Cartago, de 76 subproductos analizados solo uno de ellos superó el valor máximo permitido. Los trihalometanos encontrados de acuerdo a la Agencia Internacional de Investigación en Cáncer (por sus siglas en inglés IARC) se ubican en el grupo 2 B con evidencia de producir cáncer en animales. Se encontró gran variación de la presencia de estos subproductos en las muestras de agua de los abastecimientos que corresponden a agua con tratamiento completo (agua superficial tratada) correlacionando con lo reportado ya en la literatura, no obstante se reportó por primera vez la casi ausencia total de subproductos en cantidades que superen los máximos permitidos en aguas de origen subterráneo correlacionando con menor cantidad de carbono orgánico total, menor cantidad de cloro agregado (cloro combinado) y por ser acueductos más pequeños, menor cantidad de cloro residual. Con respecto a la formación de los subproductos, de acuerdo a la literatura, se pudo afirmar que la misma se ve favorecida con el aumento de la dosis de cloro (no necesariamente el cloro residual) y el aumento del tiempo de contacto agua-cloro, por cuanto el contenido de THMs a la salida de las plantas de tratamiento se incrementa posteriormente en muchos casos en la red, debido principalmente al mayor tiempo de contacto con la materia orgánica y con sustancias orgánicas de biofilmes en la red. De acuerdo a determinaciones anteriores en muestreos control de agua municipal el promedio de cloro residual de las plantas de tratamiento es de 1.1 mg/L y el de los sistemas de agua subterránea es de 0,6 mg/L
The gas and dust coma of Comet C/1999 H1 (Lee)
The final version is available at: http://www.aanda.orgComet Lee (C/1999 H1) was observed on June 6, 1999 when it was at rh = 0.98 AU and Δ = 1.195 AU. The spectrophotometric observations, between 0.6 and 1 μm, were aimed at the detection of the CI(1D) doublet λλ 9823/9850 Å. The non-detection of these lines, with a 3σ flux upper limit of the order of 4.6 × 10−17 erg cm−2 s−1, confirms the CO depletion already noted by other authors. Several CN and NH2 emission bands lie in that spectral range, making it possible to derive production rates for both species as ∼3.1 × 1026 s−1 and 1.2 × 1027 s−1, respectively. The oxygen forbidden line at 6300 Å was used to obtain QH2O = (1.22 ± 0.7) × 1029 s−1. Assuming that CN and NH2 are directly produced by HCN and NH3, Comet Lee has a HCN/H2O ≈ 0.25% and NH3/H2O ≈ 1% at rh = 0.98 AU, in reasonable agreement with what has been found in other long-period comets. The structural analysis carried out on cometary images acquired with broad band R Bessel filter clearly displays two pairs of ion rays likely produced by the H2O+ doublet at 6198 and 6200 Å, wavelengths covered by the bandpass filter. Identical features are found in the images acquired with the Gunn i filter. The dust brightness profiles in the east-west direction do not deviate from a ρ−m law (with 0.7 < m ≤ 1.2) as expected for a steady state model coma with a constant dust production rate and expanding at constant velocity. The dust production rate, as obtained from the A f ρ parameter, is ∼500 cm, which compared with the gas production rate classifies this comet as a dust poor one with relatively high (6.5–11.7) gas-to-dust mass ratio. Analysis of the normalized reflectivity gradient (i.e. continuum color) as a function of ρ indicates a slight reddening of the solid component in the coma at large cometocentric distances, whereas the
average dust color within an aperture of 20 000 km, centered at the nucleus, is ∼9% per 1000 Å. Mie scattering computations
applied to an ensemble of particles indicate that the dust coma is haracterised by a relative broad size distribution with a typical mean size of 1 μm. These grains might be composed of a mixture of silicates and icy material.Peer reviewe
Elastic, dielectric and electromechanical properties of (Bi0.5Na0.5)TiO3-BaTiO3 piezoceramics at the morphotropic phase boundary region
A systematic study of the functional properties of the (1-x)(Bi0.5Na0.5)TiO3–xBaTiO3 (BNT-xBT) piezoceramic system for 0.05 = x = 0.07 is performed. The samples are obtained through the conventional solid-state route. The expected microstructure for these compounds, with no significant dependence on the composition, is verified by field-emission scanning electron microscopy. The morphotropic phase boundary (MPB) is detected for x = 0.06–0.07 by means of the Rietveld analysis of X-ray diffraction data. The dielectric spectra show a frequency-independent, completely diffuse phase transition with a composition-dependent diffusivity coefficient. The depolarization temperature is effectively evaluated from pyroelectric measurements, the value being strongly dependent on the composition. A significant contribution of the extrinsic effect to elastic, dielectric and electromechanical properties is revealed for MPB BNT-xBT. The Bi3+ substitution by Ba2+ leads to the formation of A-site vacancies, which give rise to the enhancement of domain wall motion, as occurs in other perovskite-type piezoelectrics. Good functional properties are achieved for x = 0.07 (d33 = 180 pC/N), which are similar or even better than those obtained by complex synthesis routes. This system exhibits a remarkable stability in the permittivity that has hitherto not been reported. This fact may open the way for BNT-BT compositions to be used in specific applications in which lead-free piezoceramics have previously been employed with little success, e.g. in high power devices.Postprint (author's final draft
AVOCADO: A Virtual Observatory Census to Address Dwarfs Origins
Dwarf galaxies are by far the most abundant of all galaxy types, yet their
properties are still poorly understood -especially due to the observational
challenge that their intrinsic faintness represents. AVOCADO aims at
establishing firm conclusions on their formation and evolution by constructing
a homogeneous, multiwavelength dataset for a statistically significant sample
of several thousand nearby dwarfs (-18 < Mi < -14). Using public data and
Virtual Observatory tools, we have built GALEX+SDSS+2MASS spectral energy
distributions that are fitted by a library of single stellar population models.
Star formation rates, stellar masses, ages and metallicities are further
complemented with structural parameters that can be used to classify them
morphologically. This unique dataset, coupled with a detailed characterization
of each dwar's environment, allows for a fully comprehensive investigation of
their origins and to track the (potential) evolutionary paths between the
different dwarf types.Comment: 4 pages, 1 figure. To appear in the proceedings of IAU Symposium 277,
"Tracing the Ancestry of Galaxies on the Land of our Ancestors", Carignan,
Freeman, and Combes, ed
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