Hombres y barcos del comercio negrero en España (1789-1870)

El conocimiento que poseemos sobre las circunstancias en las que se desarrolló la vida de las tripulaciones de los buques españoles dedicados al tráfico de esclavos entre 1789 y1870, el periodo de mayor auge, es escaso a pesar de constituir uno de los capítulos más notables de la historia social de nuestra marina mercante. Este artículo es una primera aproximación al asunto. El trabajo está estructurado en cinco partes: panorama histórico-político, magnitud del fenómeno, marco geográfico, buques y vida de las tripulaciones. El último apartado es el más extenso y para su elaboración se han utilizado fuentes documentales inéditas hasta hoy

On the design and performance evaluation of automatic traffic report generation systems with huge data volumes

In this paper, we analyze the performance issues involved in the generation of automated traffic reports for large IT infrastructures. Such reports allow the IT manager to proactively detect possible abnormal situations and roll out the corresponding corrective actions. With the ever‐increasing bandwidth of current networks, the design of automated traffic report generation systems is very challenging. In a first step, the huge volumes of collected traffic are transformed into enriched flow records obtained from diverse collectors and dissectors. Then, such flow records, along with time series obtained from the raw traffic, are further processed to produce a usable report. As will be shown, the data volume in flow records turns out to be very large as well and requires careful selection of the key performance indicators (KPIs) to be included in the report. In this regard, we discuss the use of high‐level languages versus low‐level approaches, in terms of speed and versatility. Furthermore, our design approach is targeted for rapid development in commodity hardware, which is essential to cost‐effectively tackle demanding traffic analysis scenarios. Actually, the paper shows feasibility of delivering a large number of KPIs, as will be detailed later, for several TBytes of traffic per day using a commodity hardware architecture and high‐level languagesThis work has been partially supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund under the projects TRÁFICA (MINECO/FEDER TEC2015‐69417‐C2‐1‐R) and Procesado Inteligente de Tráfico (MINECO/FEDER TEC2015‐69417‐C2‐2‐

Thinning of the Monte Perdido Glacier in the Spanish Pyrenees since 1981

Producción CientíficaThis paper analyzes the evolution of the Monte Perdido Glacier, the third largest glacier in the Pyrenees, from 1981 to the present. We assessed the evolution of the glacier's surface area by analysis of aerial photographs from 1981, 1999, and 2006, and changes in ice volume by geodetic methods with digital elevation models (DEMs) generated from topographic maps (1981 and 1999), airborne lidar (2010) and terrestrial laser scanning (TLS, 2011, 2012, 2013, and 2014) data. We interpreted the changes in the glacier based on climate data from nearby meteorological stations. The results indicate that the degradation of this glacier accelerated after 1999. The rate of ice surface loss was almost three times greater during 1999–2006 than during earlier periods. Moreover, the rate of glacier thinning was 1.85 times faster during 1999–2010 (rate of surface elevation change  = −8.98 ± 1.80 m, glacier-wide mass balance  = −0.73 ± 0.14 m w.e. yr−1) than during 1981–1999 (rate of surface elevation change  = −8.35 ± 2.12 m, glacier-wide mass balance  = −0.42 ± 0.10 m w.e. yr−1). From 2011 to 2014, ice thinning continued at a slower rate (rate of surface elevation change  = −1.93 ± 0.4 m yr−1, glacier-wide mass balance  = −0.58 ± 0.36 m w.e. yr−1). This deceleration in ice thinning compared to the previous 17 years can be attributed, at least in part, to two consecutive anomalously wet winters and cool summers (2012–2013 and 2013–2014), counteracted to some degree by the intense thinning that occurred during the dry and warm 2011–2012 period. However, local climatic changes observed during the study period do not seem sufficient to explain the acceleration of ice thinning of this glacier, because precipitation and air temperature did not exhibit statistically significant trends during the study period. Rather, the accelerated degradation of this glacier in recent years can be explained by a strong disequilibrium between the glacier and the current climate, and likely by other factors affecting the energy balance (e.g., increased albedo in spring) and feedback mechanisms (e.g., heat emitted from recently exposed bedrock and debris covered areas).Ministerio de Economía, Industria y Competitividad - IBERNIEVE (project CGL2014-52599-P)Ministerio de Agricultura y Pesca, Alimentación y Medio Ambiente (project 844/2013

Cultural Differences between University Students in Online Learning Quality and Psychological Profile during COVID-19

During the COVID-19 pandemic, educational systems had to adapt to the social and health situation immediately. This led to the appearance of the asynchronous teaching model. Throughout the pandemic at an educational level, we can distinguish three phases, eminently online, hybrid, and face-to-face. However, the perception of educational quality in these three educational moments, considering the psychometric profile and cultural differences comparing Ibero-American countries, has not been studied. The study aims to analyze the psychological profile, and perception of quality in the teaching–learning processes at the university stage, during the three processes of educational transition during COVID-19: online, hybrid, and face-to-face. Thus, 1093 university students from Ibero-American countries were studied. Through a questionnaire, demographic, academic, and psychological variables were analyzed during three phases of the pandemic. Data suggest that Latin American students had higher levels of trait anxiety and stress perception, as well as higher levels of loneliness, during the online teaching phase (lockdown), but higher grades and higher levels of motivation compared to Europeans. Indeed, Latin Americans showed greater convenience, and preference for online learning methods. However, during the face-to-face teaching phase, European students presented greater motivation and grades, showing a greater preference for this method of learning than Latin American students. Factors such as resilience, a more unfavorable and pronounced pandemic evolution, and greater social inequities, may explain the present results. Furthermore, the present study suggests that despite the effect of the pandemic on mental health, online education is postulated as an effective teaching–learning alternative. Indeed, online teaching models have come to stay, not as a substitute, but as a tool, an essential focus of attention on these models should be conducted in European countries, while the governments of Latin American countries ensure that the infrastructures and resources are equitable to be able to correctly implement this teaching model

Bacteria associated with periodontal disease are also increased in health

The objective of this cross-sectional clinical study was to analyze the differences in the microbiome in gingival sulci of adult patients in the presence or absence of chronic periodontitis. Patients with or without periodontal disease were included in this cross-sectional study. Subgingival biofilm samples were collected and analyzed by 16S massive pyrosequencing. Functional analyses were also performed. A total of 15 phyla, 154 genera and 351 species were detected globally. Differences between disease and non-disease samples were observed in all taxonomical levels which suggest functional profile changes in the community. It was found that the main species associated with non-disease samples were reduced in disease but not completely suppressed. Analysis of the functional potential of the biofilms revealed a significantly higher activity related to endocytosis and phosphatidylinositol signaling in the disease group but lower cell adhesion molecules. Specific differences between health and disease suggest functional profile changes in the community, although bacteria associated with periodontal disease are also increased in health. Transcriptome studies should be conducted to confirm and deepen metabolic dysfunctions

Gender Differences of University Students in the Online Teaching Quality and Psychological Profile during the COVID-19 Pandemic

With the arrival of COVID-19, educational systems have had to adapt to the social and health situation immediately. This led to the appearance of the asynchronous teaching model. Throughout the pandemic, at the educational level, we can distinguish three phases, eminently online, hybrid, and finally, face-to-face. However, the perception of educational quality in these three educational moments, taking into account the psychometric profile and gender, has not been studied. Thus, 1093 university students from Ibero-American countries were analyzed. Through a questionnaire, demographic, academic, and psychological variables were analyzed at three moments during the evolution of the pandemic. Data suggest that, during the lockdown phase, while teaching was eminently online, students presented higher levels of stress and higher difficulty of learning; class attendance, convenience, preferred method of learning, grading score, and motivation were lower, compared to other phases of teaching (hybrid and face-to-face). During this period, females presented higher stress levels than males, as well as higher levels of anxiety and loneliness, without gender differences among the other studied variables. During the hybrid and face-to-face phases, male students presented higher values in the results of difficulty learning and demanding activities. No differences were seen regarding motivation, synchronous class attendance, learning level, grades, convenience, or preferred learning method. The results from the present study suggest that, despite the effect of the pandemic on mental health, asynchronous education is postulated as an effective teaching–learning alternative. Yet, a special focus should be given to female students

Social Stress Increases Cortisol and Hampers Attention in Adolescents with Excess Weight

Objective: To experimentally examine if adolescents with excess weight are more sensitive to social stress and hence more sensitive to harmful effects of stress in cognition.Design and Methods: We conducted an experimental study in 84 adolescents aged 12 to 18 years old classified in two groups based on age adjusted Body Mass Index percentile: Normal weight (n=42) and Excess weight (n=42). Both groups were exposed to social stress as induced by the virtual reality version of the Trier Social Stress Task --participants were requested to give a public speech about positive and negative aspects of their personalities in front of a virtual audience. The outcome measures were salivary cortisol levels and performance in cognitive tests before and after the social stressor. Cognitive tests included the CANTAB Rapid Visual Processing Test (measuring attention response latency and discriminability) and the Iowa Gambling Task (measuring decision-making).Results: Adolescents with excess weight compared to healthy weight controls displayed increased cortisol response and less improvement of attentional performance after the social stressor. Decision-making performance decreased after the social stressor in both groups.Conclusion: Adolescents who are overweight or obese have increased sensitivity to social stress, which detrimentally impacts attentional skills.This study has been funded by grants PSI2010-17290 (INTEROBE) from the Ministry of Innovation and Science (MICINN), and P-10-HUM-6635 (NEUROECOBE)