Ethnicity and Earnings in Urban Peru

In this paper we study the relationship between ethnic exclusion and earnings in Urban Peru. Our approach to the concept of ethnicity involves the usage of instruments in many of its several dimensions: mother tongue, parental background, religion, migration events and race. In order to approximate what can be called racial differences in a context like the Peruvian in which "racial mixture" is the main characteristic of the population, we use a score-based procedure to capture both the differences and the mixtures. By means of this procedure each individual is assigned intensities by pollsters in each of the four categories that correspond to the most easily recognized distinct racial groups in the Peruvian society: Asiatic, White, Indigenous, and Black. We find that the multidimensional race indicator is correlated with several human capital and physical capital assets, as well as with access to public services. Using Blinder-Oaxaca (B-O) decompositions we find that a substantial part of the earnings differences between racial groups cannot be explainged by differences in individual characteristics. To take into account the fact that B-O doesn't consider the probability distribution of the individual characteristics, and specifically race in our case, we also use a semi-parametric technique for the estimation of differences in hourly earnings. This estimation treats the typical wage equations in a linear fashion but let estimators for the racial intensity effects to interact freely, without restricting them to a functional form. The results suggests that among wage earners after controlling for a large set of characteristics, there are racially related earnings differences in favor of predominantly White individuals. In the case of the self-employed, none of the empirical distributions of earning differences attributable to race is substantially above zero.race discrimination, minorities, wage differentials, semi-parametric

Gender and Racial Discrimination in Hiring: A Pseudo Audit Study for Three Selected Occupations in Metropolitan Lima

In this paper, we adapt the audit studies methodology to analyze gender and racial differences in hiring for a particular segment of the market of three selected occupations in Metropolitan Lima: salespersons, secretaries and (accounting and administrative) assistants. The adapted pseudo-audit study methodology allow us to reduce the room for existence of statistical discrimination. The results suggest the existence of no significant differences in hiring rates for different gender-race groups but some systematic (and significant) differences in the aimed wages of the individuals in their job search processes.field experiments, discrimination, occupational segregation

MODELAÇÃO E INVERSÃO DE DADOS GRAVIMÉTRICOS. DETERMINAÇÃO NUMÉRICA COM APLICAÇÃO AO COMPLEXO PLUTÓNICO DE SANTA EULÁLIA

Os dados gravimétricos obtidos para o Complexo Plutónico de Santa Eulália - CPSE (Maximo, 2008; Sant'Ovaia et al., 2012) serviram de base para uma interpretação sobre a geologia 3D da região estudada. As densidades supostas das rochas são utilizadas para recalcular o campo gravítico à superfície, permitindo assim a consolidação da cartografia geológica proposta, a partir de um programa de cálculo numérico direto desenvolvido especificamente no âmbito de um projeto de investigação. Com base nos dados gravimétricos de campo é possível determinar, utilizando alguns pressupostos adicionais, o campo de densidades num volume englobando a área de estudo. Complementarmente está em desenvolvimento um outro programa numérico para efetuar esta inversão, com o objetivo de determinar as variações da densidade em profundidade a partir dos dados gravimétricos recolhidos no campo. Os resultados já obtidos com a utilização deste segundo programa (inversão) apontam para a existência de boa exatidão na determinação das densidades, a baixas profundidades (<3km). A maiores profundidades a incerteza dos valores da densidade aumenta. Em ambos os programas numéricos, a lei da gravitação universal é utilizada para relacionar densidades e acelerações gravíticas à superfície. O cálculo de g a partir de é efetuado de forma direta, admitindo valores médios regionais para e g conhecidos. Para a inversão são utilizados os mesmos princípios de base, aplicando-se o método de Monte Carlo para determinar os valores de que reproduzem as medidas de g. A abordagem apresentada tem como ponto de partida a distribuição de densidades em volumes de controlo. O domínio de cálculo é um paralelepípedo de 40x40x10 km, dividido em 4356 volumes de controlo com densidades uniformes. Os programas numéricos desenvolvidos utilizam a linguagem de programação Fortran. Na figura 1 são apresentados os resultados da inversão realizada para z = 0m, onde se pode observar que os resultados reproduzem de forma fiel a cartografia geológica da região, nomeadamente no que diz respeito às litologia aflorantes

Building monument materials during the 3rd-4rd millennium (Portugal)

Dolmens are the most conspicuous remains of the populations of the 4th and first half of 3rd millennia BCE. These tombs are impressive not only for their monumentality, but also because of the socioeconomic investment they represent for those Neolithic communities, namely from the Central-South of Portugal, who built them. Although dolmens have been studied for their funerary content and typologies, an interdisciplinary approach toward the geological characterization and sourcing of stones used in these constructions has not received enough attention from researchers. With MEGAGEO project a multidisciplinary group of geologist and archaeologists intends to assess the relationship between the distribution of dolmens in Central-South Portugal, their source materials, and the geological landscape. GIS will map the information gathered and will be used to analyse these relationships. The selection of the areas, with distinctive geologies (limestone vs granite), will allow to verify if human patterns of behaviour regarding the selection of megaliths are similar or different regionally. Geologically the first target area (Freixo, Alentejo) is dominated by a small intrusion of gabbro mingled/mixed within a granodioritic intrusion both related with variscan orogeny. Granodiorite exhibit several enclaves of igneous and metamorphic nature attesting the interaction between both igneous rocks as well with enclosing gneisses. Despite Alentejo region have a reduced number of outcrops the granodiorite provides rounded to tabular metric blocks. The gabbro is very coarse grained, sometimes with a cumulate texture, and their fracturing and weathering provide very fresh tabular blocks. The five studied dolmens (Quinta do Freixo #1 to #5) are implanted in a large granodioritic intrusion, around the gabbroic rocks, within an area of approximately 9km2. The medium grained granodiorite is ubiquity in all the dolmens slabs and occasionally it can be observed features of mixing and mingling mechanisms; interpenetration of different magmas and enclaves. There were not identified slabs of gabbros in dolmens slabs. In distances less than 100m from the dolmens, it is possible to identify an outcrop with equal features (petrographic as well geometric) with those found in the slabs. These observations agrees with previous authors (e.g. Boaventura, 2000) that favours a pragmatic attitude of Neolithic populations in the search of the appropriate slabs for construction

Thermal Transport and Physical Characteristics of Silver-Reinforced Biodegradable Nanolubricant

In this investigation, the thermal transport behavior of biodegradable lubricant reinforced with silver nanostructures (AgNs) at various filler fractions of 0.01, 0.05, 0.10, and 0.20 weight percent was evaluated over a temperature scan analysis, ranging from room temperature up to 60 °C. The experimental results revealed significant gradual enhancements in thermal conductivity as AgNs concentration and evaluating temperatures were increased. These improvements showed the important role of nanostructures’ interaction within the biodegradable lubricant. The thermal conductivity performance improved for nanolubricants ranging from 6.5% at 30 °C and 0.20 wt.% AgNs content up to a maximum 32.2%, which was obtained at 60 °C with 0.20 wt.% AgNs concentration. On the other hand, the thermal stability of reinforced lubricants was assessed through thermogravimetric kinetics analyses. The predictive curves resulting from the analyses indicated that there is an enhancement in both the onset temperature for decomposition and the percentage conversion under isothermal conditions for lubricants reinforced with AgNs. Specifically, the results show that the required temperature to achieve a 5% conversion is 100 °C higher than that calculated for bare lubricant. Moreover, the predictive analyses indicate that there is a delay in the decomposition time at isothermal conditions

A dislocation dynamics study of the strength of stacking fault tetrahedra. Part I: interactions with screw dislocations

We present a comprehensive dislocation dynamics (DD) study of the strength of stacking fault tetrahedra (SFT) to screw dislocation glide in fcc Cu. Our methodology explicitly accounts for partial dislocation reactions in fcc crystals, which allows us to provide more detailed insights into the dislocation– SFT processes than previous DD studies. The resistance due to stacking fault surfaces to dislocation cutting has been computed using atomistic simulations and added in the form of a point stress to our DD methodology. We obtain a value of 1658.9 MPa, which translates into an extra force resolved on the glide plane that dislocations must overcome before they can penetrate SFTs. In fact, we see they do not, leading to two well differentiated regimes: (i) partial dislocation reactions, resulting in partial SFT damage, and (ii) impenetrable SFT resulting in the creation of Orowan loops. We obtain SFT strength maps as a function of dislocation glide plane-SFT intersection height, interaction orientation, and dislocation line length. In general SFTs are weaker obstacles the smaller the encountered triangular area is, which has allowed us to derive simple scaling laws with the slipped area as the only variable. These laws suffice to explain all strength curves and are used to derive a simple model of dislocation–SFT strength. The stresses required to break through obstacles in the 2.5–4.8-nm size range have been computed to be 100–300 MPa, in good agreement with some experimental estimations and molecular dynamics calculations

Atomistically informed dislocation dynamics in fcc crystals

We develop a nodal dislocation dynamics (DD) model to simulate plastic processes in fcc crystals. The model explicitly accounts for all slip systems and Burgers vectors observed in fcc systems, including stacking faults and partial dislocations. We derive simple conservation rules that describe all partial dislocation interactions rigorously and allow us to model and quantify cross-slip processes, the structure and strength of dislocation junctions, and the formation of fcc-specific structures such as stacking fault tetrahedra. The DD framework is built upon isotropic non-singular linear elasticity and supports itself on information transmitted from the atomistic scale. In this fashion, connection between the meso and micro scales is attained self-consistently, with all material parameters fitted to atomistic data. We perform a series of targeted simulations to demonstrate the capabilities of the model, including dislocation reactions and dissociations and dislocation junction strength. Additionally we map the four-dimensional stress space relevant for cross-slip and relate our findings to the plastic behavior of monocrystalline fcc metal

Geometria 3D do Complexo Plutónico de Santa Eulália. Contribuição da Gravimetria

Os estudos de gravimetria em plutões graníticos tem sido efetuados com diversas finalidades,procurando perceber a sua geometria tridimensional e retirando implicações quer quanto à sua génese, quer quanto à dinâmica de processos crustais ou, ainda, retirando ilações acerca do potencial para a existência de recursos minerais com eles associados (Vigneresse 1995,Máximo, J. 2008, Sant'Ovaia et al. 2012). Os plutões graníticos são caracterizados por, normalmente, possuírem uma densidade inferior às rochas encaixantes, gerando anomalias negativas. A análise destas anomalias por modelação e principalmente por métodos de inversão permite determinar a geometria 3D dos maciços. A compreensão da existência de uma raiz simples ou de múltiplas raízes, permite afinar o modelo de génese e implantação do plutão, o que por sua vez fornece achegas fundamentais para a avaliação do potencial metalogénico. O complexo plutónico de Santa Eulália - CPSE - é constituído por duas fácies principais de rochas graníticas. A fácies central é essencialmente formada por granitos de cor cinzenta de granulometria variável e com tendência porfiroide. A fácies mais externa é constituída por um granito de grão geralmente grosseiro, essencialmente biotítica e de cor rosa

A spatial data warehouse to predict megaliths slabs sources: mixing geochemistry, petrology, cartography and archaeology for spatial analysis

MEGAGEO - Moving megaliths in the Neolithic is a project that aims to find the provenience of slabs used in the construction of dolmens. A multidisciplinary approach has been carried out with researchers from the several fields of knowledge involved. In this work it is presented a spatial data warehouse specially developed for the project, which comprises information from national archaeological databases, geographic and geological information and new geochemical and petrographic data obtained during the project. Redondo area is used as a case study for the application of the spatial data warehouse to analyze relationships between geochemistry, geology and the dolmens of the regio

Modelos no lineales para la descripción del crecimiento de cuyes (Cavia porcellus) de saca temprana

The aim of this study was to evaluate the non-linear Gompertz, logistic, Von Bertalanffi and Richards models to find the model that best describes the growth of early culling guinea pigs. The research was carried out in a commercial farm of Peru breed guinea pigs located in the province of Huaura, Peru. Ten males and 12 females were used, which were periodically weighed from birth to 69 days. The feeding was basically with green fodder. The degree of adjustment of the non-linear models of the weight and age of the animals was evaluated through the mean square of the error (CME) and the Akaike (AIC) and Bayesian (BIC) criteria. The logistic non-linear model was the one that best described the growth of the guinea pigs fed with green forage and allowed the elaboration of the growth standard for early culling.El objetivo del estudio fue evaluar los modelos no lineales Gompertz, logístico, Von Bertalanffi y Richards para hallar el modelo que mejor describa el crecimiento de cuyes de saca temprana. La investigación se desarrolló en una granja comercial de cuyes de raza Perú ubicada en la provincia de Huaura, Perú. Se utilizaron 10 machos y 12 hembras que fueron pesados periódicamente desde el nacimiento hasta los 69 días. La alimentación fue básicamente con forraje verde (maíz chala). El grado de ajuste de los modelos no lineales del peso y edad de los animales fue evaluado a través del cuadrado medio del error (CME) y los criterios Akaike (AIC) y Bayesiano (BIC). El modelo no lineal logístico fue el que mejor describió el crecimiento de los cuyes alimentados con forraje verde y permitió elaborar el estándar de crecimiento a la saca temprana