When Supply Meets Demand: Wage Inequality in Portugal

Wage inequality in Portugal increased over the last quarter of century. The period from 1982 to 1995 witnessed strong increases in both upper- and lower-tail inequality. A shortage of skills combined with skill-biased technological changes are at the core of this evolution. Since 1995, lower-tail inequality decreased, while upper-tail inequality increased at a slower rate. The supply of high-skilled workers more than doubled during this period, contributing significantly to the slowdown. Polarization of employment demand is the more credible explanation for the more recent evolution. As in other developed economies, for instance Germany and the United States, we show that institutions played a minor role in shaping changes in inequality.inequality, polarization, supply, demand, institutions

Excess Worker Turnover and Fixed-Term Contracts: Causal Evidence in a Two-Tier System

Portuguese firms engage in intense reallocation, most employers simultaneously hire and separate from workers, resulting in high excess worker turnover flows. These flows are constrained by the employment protection gap between open-ended and fixed-term contracts. We explore a reform that increased the employment protection of open-ended contracts and generated a quasi-experiment. The causal evidence points to an increase in the share and in the excess turnover of fixed-term contracts in treated firms. The excess turnover of open-ended contracts remained unchanged. This result is consistent with a high degree of substitution between open-ended and fixed-term contracts. At the firm level, we also show that excess turnover is quite heterogeneous and quantify its association with firm, match, and worker characteristics.excess worker turnover, two-tier systems, quasi-experiment, fixed-term contracts

I bet you don’t look good on the dance floor: Re-examining the innovation policy dance metaphor in the case of Colombia

Innovation heuristics offer guidance on how to navigate through the complex dynamics of innovation governance. However, further discussion is needed on the premises of such analytical tools to inquire on their implications on innovation policy and practice. This paper builds on the innovation policy dance metaphor to better grasp the ever-changing interplays (or dance) between innovation practice (I), policy (P) and theory (T). We critically assess the basic underlying assumptions of this metaphor, by examining the extent to which its heuristic pretensions are relevant in the Latin American context. To do so, we explore three illustrative cases in Colombia, shedding light on some crosscutting opportunities and gaps for the dancing metaphor across different innovation I-P-T situations. Some derived lessons suggest that dancing occurs within and/or between different governance levels, where variables such as politics shape the innovation I-P-T interplay and time defines first and second order learning pathways

Applying Machine Learning to enhance payments systems security

Ph. D. Thesis.During the last two decades, the economic losses because fraudulent card payment transactions have tripled. The significant percentage of losses is because of fraud on e-commerce transactions. Nowadays, there is a clear trend to use more and more mobile devices to make electronic purchases, and it is estimated that this trend will continue in the coming years. In the card payment scheme, big financial institutions process millions of transactions every day; thus, they can model the processed transactions to predict fraud. On the other hand, merchants process a much lower number of transactions, but they have access to valuable information that they can collect from the devices that users utilise during the transaction. In this thesis, we propose a series of measures to enhance the security of these two scenarios based on past transactional data and information collected from the users’ device. Most of the approaches proposed so far to model processed transactions were based on supervised Machine Learning techniques. We propose a fraud detection system for card payments based on an unsupervised machine learning technique; thus, the system may be able to recognise new patterns of fraud. On the other hand, we are looking far ahead, and because of the increment of use of mobile devices to conduct payments, we propose a series of measures to enhance the security of the mobile payment system. We have proposed a user identification and verification systems for smartphones. We base the identification and verification systems on motion data, so the systems will not require any explicit action from users

Análisis biomecánico de la marcha atlética, diferencias entre género y variables sensibles a la velocidad = Biomechanical analysis of race walking, gender differences and sensitive variable speed

Los objetivos fueron determinar las diferencias biomecánicas entre hombres y mujeres marchadores, e identificar las variables cinemáticas sensibles a la velocidad. Ocho marchadores de alto nivel (4 mujeres y 4 hombres) fueron evaluados a 3 velocidades en un tapiz rodante mientras se analizaban variables biomecánicas con un sistema 3D (cinemática lineal y angular) y una plataforma láser (frecuencia y amplitud de paso, tiempo de vuelo). Las mujeres marcharon con menor amplitud y mayor frecuencia de zancada que los hombres a velocidades similares. Además, mostraron una mayor amplitud y mayor distancia de impulsión relativa a la longitud de sus piernas, así como una mayor extensión de cadera en el despegue, lo que significa un mayor esfuerzo mecánico a la misma velocidad. Los hombres presentaron mayor rotación de caderas y menor separación de pies al marchar, lo que coincide con hallazgos previos. Con el incremento de la velocidad, además de la frecuencia, amplitud y tiempo de vuelo, aumentó la distancia de impulsión, sin cambios en la distancia de frenado y la oscilación del centro de gravedad. Para incrementar la velocidad, la rotación y extensión de caderas junto con la extensión de rodilla aumentaron en el momento de despegue. En conclusión, las diferencias biomecánicas de la marcha de hombres y mujeres se justifican por sus características antropométricas y físicas. Para conseguir un aumento de velocidad sin sobrepasar el límite reglamentario de tiempo de vuelo, la frecuencia, distancia de impulsión y extensión de rodilla en el despegue son factores clave=The objectives were to determine the biomechanical differences between male and female race walkers, and to identify kinematic variables sensitive to speed. Eight high-level race walkers (4 women and 4 men) were race walked at 3 different speeds on a treadmill while analysing biomechanical variables with a 3D system (linear and angular kinematics) and laser platform (stride frequency, stride length, flight time). Women race walked with less stride length but more frequently than men at similar speeds. Additionally, they showed a longer stride length and a higher foot behind distance relative to leg length, as well as a higher extension of hip at the toe-off, which means more mechanical effort at the same speed. The men presented more pelvic rotation and less separation of the feet when race walking, supporting previous findings. When increasing speed, further to the stride frequency, stride length and flight time, foot behind distance increased, without changes in foot ahead distance and the vertical displacement of body center of mass. To increase the speed, the rotation and extension of the hips along with the knee extension increased at toe-off. In conclusion, the biomechanical differences between men and women are justified by their anthropometric and physical characteristics. To increase speed without exceeding the rule of flight time, stride frequency, foot behind distance and knee extension at toe-off are key factor

In vivo forced expression of myocardin in ventricular myocardium transiently impairs systolic performance in early neonatal pig heart

[Abstract] The aim of this study was to determine the effects of forced expression of myocd-A in the left ventricular (LV) myocardium on cardiac performance in early neonatal piglets. LV transfection with the gene for homeodomain only protein (hop), an antagonist of myocd-mediated activities, was also performed. Gene delivery was performed in 6-day-old piglets using a low-traumatic, catheter-based, video-assisted procedure developed by us for direct intra-myocardial injections of plasmid DNA into 3-4 target areas of the ventral LV free wall (LVFW). Two isoforms of porcine myocd were identified, cloned and characterized: the exon 11-lacking myocd-A and its larger exon 11-containig variant, myocd-B. In neonatal piglets, myocd-A seems to be a cardio-predominant isoform enriched in the LVFW/septum, whereas the myocd-B isoform is detected not only in the heart but also in various smooth muscle cell-containing tissues. Intramyocardial myocd-A gene delivery resulted in forced transgene expression in the target areas of the LVFW as compared to controls. On day 2 post-delivery, a marked decrease of LV-end systolic pressure values (an accepted marker for impaired LV function) was observed in myocd-A-transfected piglets as compared to hop-transfected and control groups. In addition, forced myocd-A expression in the LVFW caused abnormal ECG. A significant up-regulation of the gene for fetal-predominant muscle light chain 3F myosin was detected in myocd-A-transfected LVFWs harvested on day 2 post-delivery. Extended analysis on day 7 post-delivery revealed a drop decrease in myocd-A transgene expression in target LVFW regions which was correlated with normalization of the LV systolic parameters in experimented piglets.Ministerio de Educación y Ciencia; SAF2004-01462Galicia. Consellería de Innovación, Industria e Comercio; PGIDIT04BTF16001 PR

PEDESTRIAN SEGMENTATION FROM COMPLEX BACKGROUND BASED ON PREDEFINED POSE FIELDS AND PROBABILISTIC RELAXATION

The wide use of cameras enables the availability of a large amount of image frames that can be used for people counting or to monitor crowds or single individuals for security purposes. These applications require both, object detection and tracking. This task has shown to be challenging due to problems such as occlusion, deformation, motion blur, and scale variation. One alternative to perform tracking is based on the comparison of features extracted for the individual objects from the image. For this purpose, it is necessary to identify the object of interest, a human image, from the rest of the scene. This paper introduces a method to perform the separation of human bodies from images with changing backgrounds. The method is based on image segmentation, the analysis of the possible pose, and a final refinement step based on probabilistic relaxation. It is the first work we are aware that probabilistic fields computed from human pose figures are combined with an improvement step of relaxation for pedestrian segmentation. The proposed method is evaluated using different image series and the results show that it can work efficiently, but it is dependent on some parameters to be set according to the image contrast and scale. Tests show accuracies above 71%. The method performs well in other datasets, where it achieves results comparable to stateof-the-art approaches

Exon-skipping brain natriuretic peptide variant is overexpressed in failing myocardium and attenuates brain natriuretic peptide production in vitro

Original research[Abstract] Brain natriuretic peptide/natriuretic peptide precursor B (NPPB) is one of the most studied genes in relation to heart failure (HF) conditions. However, it is still unclear as to whether alternative splicing could create NPPB mRNA variants, which may be expressed in normal and diseased myocardium. We aimed to identify and characterize a novel alternatively spliced variant of porcine and human NPPB resulting from exon 2 skipping (designated as ΔE2-NPPB). A variety of conventional molecular, biochemical and immunochemical methods were used to examine the expression and functional consequences of ΔE2-NPPB in vitro and in vivo. The pig ΔE2-NPPB mRNA is effectively translated into stable protein in cell-based assays but, in contrast to normally spliced NPPB, the ΔE2-NPPB protein is not secreted into the media. Co-transfection assays demonstrate that ΔE2-NPPB attenuates production and secretion of normally spliced NPPB, suggesting a negative feedback loop of NPPB signaling through generation of ΔE2-NPPB. The inhibitory effects of ΔE2-NPPB on the expression of NPPB are associated with sequence elements residing in exon 3 of ΔE2-NPPB. In piglets, ΔE2-NPPB gene expression is downregulated in both ventricles after birth, but it is markedly re-activated in the postnatal myocardium in experimental diastolic heart failure. In addition, we demonstrate that the exon-skipped NPPB variants are expressed in the postnatal and adult human myocardium and upregulated at end-stage HF due to dilated cardiomyopathy. Our work uncovers an important role of alternative exon skipping in the regulation of NPPB gene expression, thereby pinpointing a putative new mechanism for post-transcriptional regulation of NPPB production and secretion.Ministerio de Ciencia e Innovación; SAF2008- 00337Ministerio de Ciencia e Innovación; SAF2004-0146