Los mercados laborales latinoamericanos en los años 90: descifrar la década

(Disponible en idioma inglés únicamente) En este trabajo se analiza el desempeño reciente de los mercados laborales latinoamericanos. Hallamos que los niveles de desempleo van en aumento en la mayoría de los países y subregiones de América Latina. El aumento del desempleo durante los años 90 no obedeció a una mayor proporción de mujeres, adultos o trabajadores urbanos en la fuerza laboral, como tampoco se puede atribuir a un aumento de la demanda de trabajadores calificados. En unos pocos países, el aumento del desempleo es producto de la baja de los niveles de empleo. En el resto de los países, los niveles de desempleo pueden responder a un considerable aumento de la participación que no ha sido totalmente absorbida por los incrementos del empleo. También hallamos que una proporción considerable y, en muchos países, creciente, de trabajadores ocupan puestos de trabajo que devengan salarios sumamente bajos. Por último, los retornos a la educación superior van en aumento, mientras que los retornos a la educación secundaria disminuyen en casi todos los países.

Análisis global de pórticos de acero. Estabilidad y efectos de segundo orden

Uno de los objetivos de la presente tesina es la elaboración de un manual de cálculo para pórticos de acero, a modo de guía, que describa las especificaciones de la Instrucción EAE de Acero Estructural para el análisis global de pórticos de acero, mediante diagramas de flujo que permitan al proyectista realizar las comprobaciones necesarias para cada tipología de pórtico en función de su grado de intraslacionalidad. El estudio incluye algunas cuestiones que han surgido durante la elaboración de dicho manual, juntamente con el desarrollo de ejemplos sencillos que faciliten la aplicación de las especificaciones contenidas en la Instrucción EAE

Harrison-Z'eldovich primordial spectrum is consistent with observations

Inflation predicts primordial scalar perturbations with a nearly scale-invariant spectrum and a spectral index approximately unity (the Harrison--Zel'dovich (HZ) spectrum). The first important step for inflationary cosmology is to check the consistency of the HZ primordial spectrum with current observations. Recent analyses have claimed that a HZ primordial spectrum is excluded at more than 99% c.l.. Here we show that the HZ spectrum is only marginally disfavored if one considers a more general reionization scenario. Data from the Planck mission will settle the issue.Comment: 4 Pages, 2 Figure

The Making of Plant Armor : The Periderm

The periderm acts as armor protecting the plant's inner tissues from biotic and abiotic stress. It forms during the radial thickening of plant organs such as stems and roots and replaces the function of primary protective tissues such as the epidermis and the endodermis. A wound periderm also forms to heal and protect injured tissues. The periderm comprises a meristematic tissue called the phellogen, or cork cambium, and its derivatives: the lignosuberized phellem and the phelloderm. Research on the periderm hasmainly focused on the chemical composition of the phellem due to its relevance as a raw material for industrial processes. Today, there is increasing interest in the regulatory network underlying periderm development as a novel breeding trait to improve plant resilience and to sequester CO2. Here, we discuss our current understanding of periderm formation, focusing on aspects of periderm evolution, mechanisms of periderm ontogenesis, regulatory networks underlying phellogen initiation and cork differentiation, and future challenges of periderm research.Peer reviewe

Use of FTA® classic cards for epigenetic analysis of sperm DNA

FTA® technologies provide the most reliable method for DNA extraction. Although FTA technologies have been widely used for genetic analysis, there is no literature on their use for epigenetic analysis yet. We present for the first time, a simple method for quantitative methylation assessment based on sperm cells stored on Whatman FTA classic cards. Specifically, elution of seminal DNA from FTA classic cards was successfully tested with an elution buffer and an incubation step in a thermocycler. The eluted DNA was bisulfite converted, amplified by PCR, and a region of interest was pyrosequenced

Impact of general reionization scenarios on extraction of inflationary parameters

Determination of whether the Harrison--Zel'dovich spectrum for primordial scalar perturbations is consistent with observations is sensitive to assumptions about the reionization scenario. In light of this result, we revisit constraints on inflationary models using more general reionization scenarios. While the bounds on the tensor-to-scalar ratio are largely unmodified, when different reionization schemes are addressed, hybrid models are back into the inflationary game. In the general reionization picture, we reconstruct both the shape and amplitude of the inflaton potential. We find a broader spectrum of potential shapes when relaxing the simple reionization restriction. An upper limit of $10^{16}$ GeV to the amplitude of the potential is found, regardless of the assumptions on the reionization history.Comment: 10 Pages, 9 figure

The relationship between zinc intake and serum/plasma zinc concentration in adults: a systematic review and dose–response meta-analysis by the EURRECA Network

Dietary zinc recommendations vary widely across Europe due to the heterogeneity of pproaches used by expert panels. Under the EURRECA consortium a protocol was designed to systematically review and undertake meta-analyses of research data to create a database that includes “best practice” guidelines which can be used as a resource by future panels when setting micronutrient recommendations. As part of this process, the objective of the present study was to undertake a systematic review and meta-analysis of previously published data describing the relationship between zinc intake and status in adults. Searches were performed of literature published up to February 2010 using MEDLINE, Embase, and Cochrane Library. Data extracted included population characteristics, dose of zinc, duration of study, dietary intake of zinc, and mean concentration of zinc in plasma or serum at the end of the intervention period. An intake-status regression coefficient was estimated for each individual study, and pooled meta-analysis undertaken. The overall pooled for zinc supplementation on serum/plasma zinc concentrations from RCTs and observational studies was 0.08 (95% CI 0.05, 0.11; p<0.0001; I2 84.5%). An overall of 0.08 means that for every doubling in zinc intake, the difference in zinc serum or plasma concentration is (20.08 = 1.06), which is 6%. Whether the dose-response relationship, as provided in this paper, could be used as either qualitative or quantitative evidence to substantiate the daily zinc intake dose necessary to achieve normal or optimal levels of biomarkers for zinc status, remains a matter of discussion