Races and Racial Identity: An Approach to their Theoretical Construction from their Focus for Fernando Ortiz

The race and racial identity become in variables inside Fernando s conceptions Ortiz it figures eminent of the Cuban XX century that dedicated their life entirely to understand the Cuban thing and their essence Their contribution is indispensable for the understanding of the pillars in which settle the traditions the customs the idiosyncrasy in short the same life the legacy and the historical memory of the Cuban tow

Psychophysiological response of military pilots in different combat flight maneuvers in a flight simulator

Objective: To analyze the psychophysiological response during takeoff, landing, air-air attack and air-ground attack maneuvers. Methods: A total of 11 expert pilots (age=33.36 (5.37)) from the Spanish Air Force participated in this cross-sectional study. Participants had to complete in a flight simulator the following missions: 1) takeoff; 2) Air-air attack; 3) Air-Ground attack, and 4) Landing. The electroencephalographic activity (EEG) and heart rate variability (HRV) were collected during all these maneuvers. Results: Significant higher values of theta (during takeoff, air-air attack and air-ground attack) EEG power spectrum were obtained when compared to baseline. Significant difference in the P3 scalp location was observed between landing and takeoff maneuvers in the beta EEG power spectrum. Furthermore, significant lower values of HRV were obtained during takeoff, landing, air-air attack and air-ground attack when compared to baseline values. Also, landing showed a higher sympathetic response when compared to takeoff maneuver. Conclusion: Takeoff, landing, air-air attack or air-ground attack maneuvers performed in a flight simulator produced significant changes in the electroencephalographic activity and autonomic modulation of professional pilots. Beta EEG power spectrum modifications suggest that landing maneuvers induced more attentional resources than takeoff. In the same line, a reduced HRV during landing was obtained when compared to takeoff. These results should be considered to training purposes

El aprendizaje basado en problema para activar la resolución de problemas con el uso de herramientas informáticas (Revisión).

Problem-based learning is characterized by the fact that learning is student-centered, and that it is meaningful; The process of solving problems with the use of computer tools is developed based on small work groups, which learn collaboratively in their learning process. For the development of this work, techniques such as observation of classes, interviews with students are used. The objective is to describe the implementation of Problem-Based Learning in solving problems based on data at the Pre-university educational level.El aprendizaje basado en problemas se caracteriza por ser significativo y estar centrado en el estudiante; el proceso de resolución de problemas con el uso de herramientas informáticas se desarrolla en base a grupos pequeños de trabajo que aprenden de manera colaborativa en su proceso de aprendizaje. Para el desarrollo de este trabajo se emplean técnicas como observación a clases y entrevista a estudiantes. El objetivo es describir la implementación del aprendizaje basado en problemas en la resolución de problemas sobre base de datos en el nivel educativo Preuniversitario

Modeling performance of Hadoop applications: A journey from queueing networks to stochastic well formed nets

Nowadays, many enterprises commit to the extraction of actionable knowledge from huge datasets as part of their core business activities. Applications belong to very different domains such as fraud detection or one-to-one marketing, and encompass business analytics and support to decision making in both private and public sectors. In these scenarios, a central place is held by the MapReduce framework and in particular its open source implementation, Apache Hadoop. In such environments, new challenges arise in the area of jobs performance prediction, with the needs to provide Service Level Agreement guarantees to the enduser and to avoid waste of computational resources. In this paper we provide performance analysis models to estimate MapReduce job execution times in Hadoop clusters governed by the YARN Capacity Scheduler. We propose models of increasing complexity and accuracy, ranging from queueing networks to stochastic well formed nets, able to estimate job performance under a number of scenarios of interest, including also unreliable resources. The accuracy of our models is evaluated by considering the TPC-DS industry benchmark running experiments on Amazon EC2 and the CINECA Italian supercomputing center. The results have shown that the average accuracy we can achieve is in the range 9–14%

Appointing Women to Boards: Is There a Cultural Bias?

Companies that are serious about corporate governance and business ethics are turning their attention to gender diversity at the most senior levels of business (Institute of Business Ethics, Business Ethics Briefing 21:1, 2011). Board gender diversity has been the subject of several studies carried out by international organizations such as Catalyst (Increasing gender diversity on boards: Current index of formal approaches, 2012), the World Economic Forum (Hausmann et al., The global gender gap report, 2010), and the European Board Diversity Analysis (Is it getting easier to find women on European boards? 2010). They all lead to reports confirming the overall relatively low proportion of women on boards and the slow pace at which more women are being appointed. Furthermore, the proportion of women on corporate boards varies much across countries. Based on institutional theory, this study hypothesizes and tests whether this variation can be attributed to differences in cultural settings across countries. Our analysis of the representation of women on boards for 32 countries during 2010 reveals that two cultural characteristics are indeed associated with the observed differences. We use the cultural dimensions proposed by Hofstede (Culture’s consequences: International differences in work-related values, 1980) to measure this construct. Results show that countries which have the greatest tolerance for inequalities in the distribution of power and those that tend to value the role of men generally exhibit lower representations of women on boards

Corporate governance and national institutions: A review and emerging research agenda

We present a critique of corporate governance research grounded in agency theory and propose that cross-national comparison of corporate governance should consider how the nature and extent of agency relationships differ across different institutional contexts. Building on prior governance studies grounded in sociology and organizational theory we argue that performance outcomes of boards of directors, ownership concentration, and executive incentives may differ depending on the legal system and institutional characteristics in a specific country. Institutions may also affect the extent of complimentarity/substitution among different firm-level governance practices producing patterned variations in firm-level governance mechanisms. Our discussion suggests that researchers need to develop more holistic, institutionally embedded governance framework to analyze organizational outcomes of various governance practices

Nucleotide and phylogenetic analyses of the Chlamydia trachomatis ompA gene indicates it is a hotspot for mutation

<p>Abstract</p> <p>Background</p> <p>Serovars of the human pathogen <it>Chlamydia trachomatis </it>occupy one of three specific tissue niches. Genomic analyses indicate that the serovars have a phylogeny congruent with their pathobiology and have an average substitution rate of less than one nucleotide per kilobase. In contrast, the gene that determines serovar specificity, <it>ompA</it>, has a phylogenetic association that is not congruent with tissue tropism and has a degree of nucleotide variability much higher than other genomic loci. The <it>ompA </it>gene encodes the major surface-exposed antigenic determinant, and the observed nucleotide diversity at the <it>ompA </it>locus is thought to be due to recombination and host immune selection pressure. The possible contribution of a localized increase in mutation rate, however, has not been investigated.</p> <p>Results</p> <p>Nucleotide diversity and phylogenetic relationships of the five constant and four variable domains of the <it>ompA </it>gene, as well as several loci surrounding <it>ompA</it>, were examined for each serovar. The loci flanking the <it>ompA </it>gene demonstrated that nucleotide diversity increased monotonically as <it>ompA </it>is approached and that their gene trees are not congruent with either <it>ompA </it>or tissue tropism. The variable domains of the <it>ompA </it>gene had a very high level of non-synonymous change, which is expected as these regions encode the surface-exposed epitopes and are under positive selection. However, the synonymous changes are clustered in the variable regions compared to the constant domains; if hitchhiking were to account for the increase in synonymous changes, these substitutions should be more evenly distributed across the gene. Recombination also cannot entirely account for this increase as the phylogenetic relationships of the constant and variable domains are congruent with each other.</p> <p>Conclusions</p> <p>The high number of synonymous substitutions observed within the variable domains of <it>ompA </it>appears to be due to an increased mutation rate within this region of the genome, whereas the increase in nucleotide substitution rate and the lack of phylogenetic congruence in the regions flanking <it>ompA </it>are characteristic motifs of gene conversion. Together, the increased mutation rate in the <it>ompA </it>gene, in conjunction with gene conversion and positive selection, results in a high degree of variability that promotes host immune evasion.</p

Corporate boards and the performance of Asian firms: A meta-analysis

The prevalence of ownership concentration in Asian firms presents a challenge to the influential agency theory-based understanding of the role of corporate boards. In this paper we develop and test hypotheses about board attributes and firm performance that reflect Asian institutional conditions. We present the first meta-analysis of the relationship between board attributes and performance of Asian firms using a varied set of meta-analytical techniques on a database of 86 studies covering nine Asian countries. First, we find that board structure and composition preferences are influenced by the identity of the concentrated owner. Second, consistent with US data, we find very limited evidence of a direct relationship between board attributes and firm financial performance in the Asian context. Third, we find that the relationship between board structure and composition and firm performance is mediated by the revealed strategic preferences of Asian firms specifically by the level of R&D investment

A New Eusuchian Crocodyliform with Novel Cranial Integument and Its Significance for the Origin and Evolution of Crocodylia

Crocodyliforms were one of the most successful groups of Mesozoic tetrapods, radiating into terrestrial, semiaquatic and marine environments, while occupying numerous trophic niches, including carnivorous, insectivorous, herbivorous, and piscivorous species. Among these taxa were the enigmatic, poorly represented flat-headed crocodyliforms from the late Cretaceous of northern Africa. Here we report a new, giant crocodyliform from the early Late Cretaceous (Cenomanian) Kem Kem Formation of Morocco. Represented by a partial braincase, the taxon has an extremely long, flat skull with large jaw and craniocervical muscles. The skull roof is ridged and ornamented with a broad, rough boss surrounded by significant vascular impressions, likely forming an integumentary structure unique among crocodyliforms. Size estimates using endocranial volume indicate the specimen was very large. The taxon possesses robust laterosphenoids with laterally oriented capitate processes and isolated epipterygoids, features allying it with derived eusuchians. Phylogenetic analysis finds the taxon to be a derived eusuchian and sister taxon to Aegyptosuchus, a poorly understood, early Late Cretaceous taxon from the Bahariya formation. This clade forms the sister clade of crown-group Crocodylia, making these taxa the earliest eusuchian crocodyliforms known from Africa. These results shift phylogenetic and biogeographical hypotheses on the origin of modern crocodylians towards the circum-Tethyean region and provide important new data on eusuchian morphology and evolution