Meritocracy and the inheritance of advantage

We present a model where more accurate information on the background of individuals facilitates statistical discrimination, increasing inequality and intergenerational persistence in income. Surprisingly, more accurate information on the actual capabilities of workers leads to the same result - firms give increased weight to the more accurate information, increasing inequality, which itself fosters discrimination. The rich take advantage of this through educational investments in their children, and mobility decreases as a consequence of an increase in the ability to reward talent. Using our model to interpret the data suggests that a country like the US might indeed be a land of opportunity for the sufficiently able, as conditional on ability background may have relatively little effect. Nevertheless the US has a relatively low degree of intergenerational mobility precisely because meritocracy facilitates a high correlation of ability with background

Validity and reliability of three teachers’ ratings scales of socials be-haviors in preschoolers and scholars children

Estudiamos la validez y confiabilidad de tres escalas para evaluar conductas sociales niños y niñas costarricenses de preescolar y primer grado (n=262). Una de las escalas evalúa el comportamiento prosocial (ECPRO), otra evalúa la habilidad de explotar la experticia de los demás (EXHAD), y una más evalúa el comportamiento maquiavélico (EMach) en el ámbito escolar. Las escalas son completadas por docentes previamente capacitadas, de modo que el puntaje de cada niño o niña depende del criterio de su maestra respectiva. La estructura factorial de cada escala fue evaluada mediante un análisis de componentes principales. Según este análisis la ECPRO exhibió una estructura unidimensional caracterizada por un componente denominado “Disposición para Ayudar a los Otros”, la EXHAD mostró dos componentes principales denominados “Aprendizaje Social por Observación” y “Explotación de la Frutos de la Experticia de los Demás”, y la EMach reveló tres componentes: “Tácticas Maquiavélicas”, “Actitudes Ambivalentes hacia los Demás” y “Comprensión Social”. Las escalas arrojaron evidencia sobre una adecuada confiabilidad interna y validez de constructo. La ECPRO y la EMach evidenciaron validez discriminante entre sí. Además, estos hallazgos sugieren que el criterio de las maestras es una muy buena alternativa para evaluar este tipo de conductas socialesThe purpose of this study was to expose validity and reliability of three teacher’s ratings scales of socials behaviors in one sample (N=262) of preschoolers and scholars (grade one) Costa Ricans children. We design one scale of prosocial behavior (ECPRO) and other to evaluate the ability of exploiter the other’s expertise (EXHAD). Moreover we adaptone scale of machiavellian behavior (EMach). Teachers completed three scales for each participant. Factor structure was evaluated by principal components analysis. This analysis show that ECPRO is form by one component “Disposition for help others”, EXHAD is constitute by two components “Social Learning by Observation” and “Exploiting the Fruits of Other’s Expertise”; whereas EMach is constitute by three components “Machiavellian Tactics”, “Ambivalent Attitudes Toward the Others” and“Social Understanding”. The three teacher’s ratings scales show evidence of construct validity and internal reliability; furthermore ECPRO and EMach show discriminant validity. In addition these findings suggest that teachers are an excellent choice to evaluate this kind of socials behaviors.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Neurociencias (CIN

First evidence for an aposematic function of a very common color pattern in small insects

Many small parasitoid wasps have a black head, an orange mesosoma and a black metasoma (BOB color pattern), which is usually present in both sexes. A likely function of this widespread pattern is aposematic (warning) coloration, but this has never been investigated. To test this hypothesis, we presented spider predators (Lyssomanes jemineus), both field-captured and bred in captivity from eggs, to four wasp genera (Baryconus, Chromoteleia, Macroteleia and Scelio), each genus being represented by a BOB morphospecies and black morphospecies. We also used false prey, consisting of lures made of painted rice grains. Behavioral responses were analyzed with respect to presence or absence of the BOB pattern. In order to better understand the results obtained, two additional studies were performed. First, the reflection spectrum of the cuticle of the wasp and a theoretical visual sensibility of the spider were used to calculate a parameter we called “absorption contrast” that allows comparing the perception contrast between black and orange in each wasp genus as viewed by the spider. Second, acute toxicity trials with the water flea, Daphnia magna, were performed to determine toxicity differences between BOB and non-BOB wasps. At least some of the results suggest that the BOB color pattern may possibly play an aposematic role.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM

New excavations at the HWK EE site: Archaeology, paleoenvironment and site formation processes during late Oldowan times at Olduvai Gorge, Tanzania

This paper reports the results of renewed fieldwork at the HWK EEsite(Olduvai Gorge, Tanzania). HWK EEis positioned across the boundary between Lower andMiddle Bed II, a crucialinterval for studyingthe emergence of the Acheulean at Olduvai Gorge. Our excavations at HWK EEhave produced one of the largest collections of fossils and artefacts from any Oldowan site, distributed across several archaeological units and a large excavation surface in four separate trenches thatcan be stratigraphically correlated. Here we present the main stratigraphic and archaeological units and discuss site formation processes.Results show a great density of fossils and stone tools vertically through two stratigraphic intervals (Lemuta and Lower Augitic Sandstone)and laterally across an area of around 300 m2, and highlight the confluence of biotic and abiotic agents in the formation of the assemblage. The large size and diversityof the assemblage, as well as its good preservation, qualify HWK EEas a reference sitefor the study of the late Oldowan at Olduvai Gorge and elsewhere in Africa. In addition, thedescriptionof the stratigraphic and archaeological sequenceof HWK EE presented in this paper constitutesthe foundation for further studies on hominin behaviour and palaeoecologyin Lower and Middle Bed II

Survival of Late Pleisticene Hunter-gatherer ancestry in the Iberian Peninsula

The Iberian Peninsula in southwestern Europe represents an important test case for the study of human population movements during prehistoric periods. During the Last Glacial Maximum (LGM), the peninsula formed a periglacial refugium for hunter-gatherers (HGs) and thus served as a potential source for the re-peopling of northern latitudes. The post-LGM genetic signature was previously described as a cline from Western HG (WHG) to Eastern HG (EHG), further shaped by later Holocene expansions from the Near East and the North Pontic steppes. Western and central Europe were dominated by ancestry associated with the 14,000-year-old individual from Villabruna, Italy, which had largely replaced earlier genetic ancestry, represented by 19,000-15,000-year-old individuals associated with the Magdalenian culture. However, little is known about the genetic diversity in southern European refugia, the presence of distinct genetic clusters, and correspondence with geography. Here, we report new genome-wide data from 11 HGs and Neolithic individuals that highlight the late survival of Paleolithic ancestry in Iberia, reported previously in Magdalenian-associated individuals. We show that all Iberian HGs, including the oldest, a 19,000-year-old individual from El Mirón in Spain, carry dual ancestry from both Villabruna and the Magdalenian-related individuals. Thus, our results suggest an early connection between two potential refugia, resulting in a genetic ancestry that survived in later Iberian HGs. Our new genomic data from Iberian Early and Middle Neolithic individuals show that the dual Iberian HG genomic legacy pertains in the peninsula, suggesting that expanding farmers mixed with local HGs

Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model

Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO