22,468 research outputs found
Fundamental Principles and Rights At Work: Value, Viability, Incidence and Importance as Elements For Economic Progress and Social Justice
Working Paper prepared for the ILO by Maria Luz Vega Ruiz and Daniel Martinez, focusing on the rights at work in Latin America and the Caribbean
Global superscaling analysis of quasielastic electron scattering with relativistic effective mass
We present a global analysis of the inclusive quasielastic electron
scattering data with a superscaling approach with relativistic effective mass.
The SuSAM* model exploits the approximation of factorization of the scaling
function out of the cross section under quasifree conditions. Our
approach is based on the relativistic mean field theory of nuclear matter where
a relativistic effective mass for the nucleon encodes the dynamics of nucleons
moving in presence of scalar and vector potentials. Both the scaling variable
and the single nucleon cross sections include the effective mass as a
parameter to be fitted to the data alongside the Fermi momentum . Several
methods to extract the scaling function and its uncertainty from the data are
proposed and compared. The model predictions for the quasielastic cross section
and the theoretical error bands are presented and discussed for nuclei along
the periodic table from to : H, H, He, He,
C, Li, Be, Mg, Ni,
Y, Sn, Ta, W, Au, O, Al,
Ca, Ca, Fe, Pb, and U.
We find that more than 9000 of the total data fall within the
quasielastic theoretical bands. Predictions for Ti and Ar are
also provided for the kinematics of interest to neutrino experiments.Comment: 26 pages, 20 figures and 4 table
Learning Disentangled Representations with Reference-Based Variational Autoencoders
Learning disentangled representations from visual data, where different
high-level generative factors are independently encoded, is of importance for
many computer vision tasks. Solving this problem, however, typically requires
to explicitly label all the factors of interest in training images. To
alleviate the annotation cost, we introduce a learning setting which we refer
to as "reference-based disentangling". Given a pool of unlabeled images, the
goal is to learn a representation where a set of target factors are
disentangled from others. The only supervision comes from an auxiliary
"reference set" containing images where the factors of interest are constant.
In order to address this problem, we propose reference-based variational
autoencoders, a novel deep generative model designed to exploit the
weak-supervision provided by the reference set. By addressing tasks such as
feature learning, conditional image generation or attribute transfer, we
validate the ability of the proposed model to learn disentangled
representations from this minimal form of supervision
Global dynamics and imbalance effects in the Lucas Uzawa model : further results
In this paper we use a new analytical approach to the Lucas-Uzawa model (Boucekkine and Ruiz-Tamarit, 2007) to extend the existinc results on the dynamics and notably on the imbalance effects arising in the model. The approach does not only allow to extend the traditional analysis to any initial conditions for all variables in level, but it also permits a more general investigation of imbalance effectsLucas-Uzawa; hypergeometric functions; imbalance effects; global dynamics
Assessment of the vegetation cover in a burned area 22-years ago using remote sensing techniques and GIS analysis (Sierra de las Nieves, South of Spain).
The study aim was to characterize the vegetation cover in a burned area 22-years ago considering the previous
situation to wildfire in 1991 and the current one in 2013. The objectives were to: (i) compare the current and previous
vegetation cover to widlfire; (ii) evaluate whether the current vegetation has recovered the previous cover to
wildfire; and (iii) determine the spatial variability of vegetation recovery after 22-years since the wildfire.
The study area is located in Sierra de las Nieves, South of Spain. It corresponds to an area affected by a wildfire in
August 8th, 1991. The burned area was equal to 8156 ha. The burn severity was spatially very high. The main geographic
features of the burned area are: mountainous topography (altitudes ranging from 250 m to 1500 m; slope
gradient >25Remote sensing techniques and GIS analysis has been applied to achieve the objectives. Landsat 5 and
Landsat 8 images were used: July 13th, 1991 and July 1st, 2013, for the previous wildfire situation and 22-years
after, respectively. The 1990 CORINE land cover was also considered to map 1991 land uses prior the wildfire.
Likewise, the Andalucía Regional Government wildfire historic records were used to select the burned area and
its geographical limit. 1991 and 2013 land cover map were obtained by means of object-oriented classifications.
Also, NDVI and PVI1 vegetation indexes were calculated and mapped for both years. Finally, some images transformations
and kernel density images were applied to determine the most recovered areas and to map the spatial
concentration of bare soil and pine cover areas in 1991 and 2013, respectively.
According to the results, the combination of remote sensing and GIS analysis let map the most recovered areas
affected by the wildfire in 1991. The vegetation indexes indicated that the vegetation cover in 2013 was still lower
than that mapped just before the 1991 widlfire in most of the burned area after 22-years. This result was also confirmed
by other techniques applied. Finally, the kernel density surface let identify and locate the most recovered
areas of pine cover as well as those areas that still remain totally or partially uncovered (bare soil.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Global dynamics and imbalance effects in the Lucas-Uzawa model: further results
In this paper we use a new analytical approach to the Lucas-Uzawa model (Boucekkine and Ruiz Tamarit, 2007) to extend the existing results on the dynamics, and notably on the imbalance effects arising in the model. The approach does not only allow to extend the traditional analysis to any initial conditions and for all variables in level, but it also permits a more general investigation of imbalance effects.Lucas-Uzawa, hypergeometric functions, imbalance effects, global dynamics
Growth vs. level effect of population change on economic development: An inspection into human-capital-related mechanisms
This paper studies the different mechanisms and the dynamics through which demography is channelled to the economy. We analyze the role of demographic changes in the economic development process by studying the transitional and the long-run impact of both the rate of population growth and the initial population size on the levels of per capita human capital and income. We do that in an enlarged Lucas-Uzawa model with intergenerational altruism. In contrast to the existing theoretical literature, the long-run level effects of demographic changes, i.e. their impact on the levels of the variables along the balanced growth path, are deeply characterized in addition to the more standard long-run growth effects. We prove that the level effect of the population rate of growth is non-negative (positive in the empirically most relevant case) for the average level of human capital, but a priori ambiguous for the level of per capita income due to the interaction of three transmission mechanisms of demographic shocks, a standard one (dilution) and two non-standard (altruism and human capital accumulation). Overall, the sign of the level effects of population growth depend on preference and technology parameters, but numerically we show that the joint negative effect of dilution and altruism is always stronger than the finduced positive human capital effect. The growth effect of population growth depends basically on the attitude to intergenerational altruism and intertemporal substitution. Moreover, we also prove that the long-run level effects of population size on per capita human capital and income may be negative, nil, or positive, depending on the relationship between preferences and technology, while its growth effect is zero. Finally, we show that the model is able to replicate complicated time relationships between economic and demographic changes. In particular, it entails a negative effect of population growth on per capita income, which dominates in the initial periods, and a positive effect which restores a positive correlation between population growth and economic performance in the long term.Human Capital, Population Growth, Population Size, Endogenous Growth, Level Effect, Growth Effect
Thermochemical Conversion of Guaiacol Over Unsupported Tungsten Oxide and Nickel Supported Catalysts
Interest in conversion of biomass into renewable fuels has motivated development of thermochemical methods for production of bio-oil and development of hydrodeoxygenation catalysts for upgrading the oil. Two types of catalysts were investigated. The catalytic activity of unsupported tungsten oxide bronze catalysts for the conversion of guaiacol was explored as a representative compound from bio-oil. The reactions were carried out in a trickle bed reactor at various concentrations of the reactant and hydrogen pressure, as well as varying catalyst activation and reaction temperatures. The reaction pathway from guaiacol to phenol by demethoxylation, followed by hydrogenation to cyclohexanol, and finally dehydration to cyclohexene was determined experimentally. Kinetic data revealed approximately first order dependence on hydrogen pressure and zeroth order dependence on guaiacol concentration. Langmuir- Hinshelwood-Hougan-Watson models were tested within a plug flow reactor model. The best fit was for a reaction mechanism in which the guaiacol methoxy C-O bond scission was the rate controlling step with guaiacol and some phenol blocking active sites. Catalytic activity and selectivity of supported Ni-based catalysts were also studied for the same model compound (guaiacol) in order to evaluate the role of metal hydrogenation sites and acid dehydration sites. The supports used were SiO2, Al2O3 and SiO2-Al2O3. All catalysts were prepared by the incipient wetness impregnation method and were characterized by different physico-chemical techniques. Conversion reactions were carried out in a batch reactor at 5 MPa of H2 pressure and 300 °C. The maximum catalytic activity among the Ni/Al2O3 catalysts was attributed to the formation of a greater number of active metal sites arising from an optimal nickel dispersion at a loading of 8 wt%. At higher Ni content, the formation of Ni aggregates was observed resulting in loss of active sites. The selectivity (at constant conversion and metal loading) toward deoxygenated products, cyclohexene and cyclohexane, was clearly related to the acid sites of the support, which were much greater on SiO2-Al2O3
African Influences in Contemporary Cuban Art The Work of Manuel Mendive
Manuel Mendive (b.1944) was part of the first generation of Cuban artists to emerge from Cuba\u27s national fine arts academy, San Alejandro, after 1959. Regarded as one of the foremost contemporary artists in Cuba and the Caribbean, Mendive incorporates visual elements rooted in West African religious and visual traditions into his painting. This lecture will look at the formative influences on Mendive\u27s early work and will explore his mainstream academic training, the contextual impact of this local community, and the effect of his African consciousness, specifically the strands of Yoruba culture present in his Cuban heritage.https://digitalcommons.fiu.edu/cri_events/1355/thumbnail.jp
Available water modifications by topsoil treatments under mediterranean semiarid conditions: afforestation plan
During dry periods in the Mediterranean area, the lack of water entering the soil matrix reduces organic contribu-
tions to the soil. These processes lead to reduced soil fertility and soil vegetation recovery which creates a positive
feedback process that can lead to desertification. Restoration of native vegetation is the most effective way to
regenerate soil health, and control runoff and sediment yield.
In Mediterranean areas, after a forestry proposal, it is highly common to register a significant number of
losses for the saplings that have been introduced due to the lack of rainfall. When no vegetation is established,
organic amendments can be used to rapidly protect the soil surface against the erosive forces of rain and runoff.
In this study we investigated the hydrological effects of five soil treatments in relation to the temporal vari-
ability of the available water for plants. Five amendments were applied in an experimental set of plots: straw
mulching; mulch with chipped branches of Aleppo Pine (Pinus halepensis L.); TerraCotten hydroabsobent
polymers; sewage sludge; sheep manure and control. Plots were afforested following the same spatial pattern, and
amendments were mixed with the soil at the rate 10 Mg ha-1.
In control plots, during June, July, August and September, soils were registered below the wilting point,
and therefore, in the area of water unusable by plants. These months were coinciding with the summer mediter-
ranean drought. This fact justifies the high mortality found on plants after the seeding plan. Similarly, soils have
never exceeded the field capacity value measured for control plots. Conversely, in the straw and pinus mulch, soils
were above the wilting point during a longer time than in control plots. Thus, the soil moisture only has stayed
below the 4.2 pF suction in July, July and August. Regarding the amount of water available was also higher,
especially in the months of December, January and February. However, the field capacity value measured has not
showed any differences regarding the control. For these treatments, the survival sapling rates measured were the
highest.
Sludge, manure and polymers showed a moisture retention capacity slightly more limited than straw and
pinus mulch. Likewise, it has been found that the area of usable water by plants was also lower, especially during
the months of January and February. This situation is especially sharpened in plots amended with manure. In
this treatment, the upper part of the soil profile was below the wilting point for six months a year (from April to
August). For this treatment, the survival sapling rates measured were the lowest.
In conclusion, from a land management standpoint, the pinus and straw mulch treatments have been shown
as effective methods reducing water stress for plants. In this research, mulching has been proved as a significant
method to reduce the mortality sapling rates during the mediterranean summer drought.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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