Synoptic-scale variability and its relationship with total ozone and Antarctic vortex displacements

The main synoptic-scale circulation anomaly pattern over extratropical South America during the austral spring (September-November) is identified by means of rotated extended empirical orthogonal function techniques, applied to the meridional wind perturbation time series at 300 hPa. The dataset is based on 15 spring seasons (1979-93) of meteorological data from the National Centers for Environmental Prediction-Department of Energy Atmospheric Model Intercomparison Project version-2 daily averaged reanalyses, given in 17 vertical levels from 1000 to 10 hPa. The total-ozone daily measurements for the same period are from the Total Ozone Mapping Spectrometer instrument (version 7). The principal synoptic-scale anomaly pattern is associated with an anticyclone-cyclone pair evolving eastward along subpolar latitudes (and hence it is termed the subpolar mode), with a typical length scale of 5000 km and a phase velocity of 8 m s-1. The subpolar-mode waves, which display the main characteristics of midlatitude baroclinic waves, typically maximize near or above the tropopause and propagate upward into the lower stratosphere, showing large amplitudes even at 50 hPa and above. Subpolar-mode-related circulation anomalies are found to be responsible for large total-ozone daily fluctuations near southern South America and nearby regions. In the positive phase of the subpolar mode, total-ozone fluctuations, which are negative, adopt a sigmoid structure, with a zonal scale as large as the anticyclone-cyclone pair. Moreover, it is herein shown that the associated anticyclone produces a local ozone-column decrease to the north and east of its center, due to adiabatic uplift of air parcels in the upper troposphere and lower stratosphere. At the same time, the downstream cyclonic disturbance is responsible for large negative total-ozone anomalies to the west and south of its center. As the cyclone develops in the lower stratosphere, it promotes the northward incursion of the Antarctic vortex up to about 55°S, along with air masses of highly depleted ozone levels.Fil: Vigliarolo, Paula Karina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Vera, Carolina Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Diaz, Susana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin

Interannual and interdecadal variability of atmospheric synoptic-scale activity in the Southern Hemisphere

[1] A rotated empirical orthogonal function analysis was applied to anomalies of July atmospheric short time scale variability (or storm tracks) over the Southern Hemisphere (SH) using NCEP reanalyses. The study reveals the existence of two leading modes of storm-track variations, the first one describing storm-track changes along the subtropical Pacific and the second one associated with variations over southeast Pacific Ocean. The principal components of both modes exhibit significant variability on interannual (2–7 years) and interdecadal (longer than 7 years) time scales. The interannual variation of the first mode is closely linked to ENSO variability. The corresponding signal on SST anomalies shows a conspicuous maximum over central equatorial Pacific, while the signature on geopotential-height anomalies shows the typical Pacific South America pattern characterized by a Rossby wave train propagating poleward from the tropics. On interdecadal time scales, the first mode is related to SST anomalies over the subtropical portions of the Pacific, Atlantic, and Indian Oceans and to a Rossby wave train with strongest signals over the southeast Pacific and the Antarctic Peninsula. The second mode that represents storm-track changes west of the Antarctic Peninsula is related on interannual time scales to SST anomalies over western Pacific between 40°S and 20°S, while on interdecadal time scales, it does not seem to be significantly related to SST changes in any of the basins. In particular, the spatial signature of the REOF2 interdecadal variability on the SH circulation corresponds to the well-known high latitude mode characterized by a monopole over the Antarctica and a three-wave pattern at middle latitudes.Fil: Vera, Carolina Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentin

Implementación de la Gestión de Adquisiciones de acuerdo a la metodología del Project Management Institute en proyectos de construcción

Actualmente, la gestión de proyectos cumple un rol muy importante en el éxito y buen desempeño de las diferentes compañías. Toda vez que, involucra lineamientos que de ser aplicados, optimizan la ejecución de sus proyectos, obteniendo con mejores resultados en cuanto a costo, tiempo y calidad. Dentro de la dirección de proyectos se encuentran grupos de procesos y áreas de conocimientos que al interactuar definen todos los procedimientos en los cuales se encuentran las buenas prácticas para la generación y ejecución de proyectos. La dirección del presente análisis se realizó desde la Gestión de Adquisiciones, el cual es uno de los procesos de mayor relevancia en proyectos. La implementación de la metodología del PMI en la Gestión de Adquisiciones de una compañía del sector de la construcción, demanda una investigación de los lineamientos consignados en el PMBOK, para posteriormente realizar un diagnóstico de la situación actual en el cual se identifiquen, los elementos más importantes a aplicar, los impactos y resultados que generan y las acciones a ejecutar. En el caso de estudio, los resultados obtenidos fueron positivos ya que permitieron una optimización de recursos y una operación más organizada y vinculada con las demás áreas de la compañía.Nowadays, the Project Management has a paramount role in the success and the good performance of companies. It involves some guidelines that, if applied, optimize the execution of projects, improving results in cost, time and quality. The Project Directorate or Project Management is composed by Process Groups and Knowledge Areas, which jointly define the procedures that contain the best practices for the generation and execution of the projects. This text’s (analysis) approach is in the field of Procurement Management, which is one of the most relevant processes in Projects. The implementation of the PMI methodology in Procurement Management, regarding a construction company, demands an investigation of the guidelines recorded in the PMBOK, in order to realize a diagnosis of the current situation of the company, identifying the most relevant elements to be applied, their impacts and results, and the actions that are to be executed. In the case at hand, all the results obtained were positive, and allowed an optimization of resources, and an organized operation involving other areas of the company

El impacto de las tecnologías educativas en la educación superior

The formation of human capital is key to countries’ social, cultural and economic development. The current literature pays considerable attention to the ever-increasing proliferation of technology in the careers of college and graduate school. While the presence of educational technology in higher education offers multiple benefits, its implementation also presents challenges. The literature has considered multiple tools for improving learning processes. The results of such tools vary and are difficult to measure in terms of quality. In this document, we analyze the issues surrounding educational technology in higher education.La formación de capital humano es clave para el desarrollo social, cultural y económico de los países. La literatura actual presta una atención considerable a la proliferación cada vez mayor de la tecnología en las carreras de los graduados universitarios. Si bien la presencia de tecnología educativa en la educación superior ofrece múltiples beneficios, su implementación también presenta desafíos. La literatura ha considerado múltiples herramientas para mejorar los procesos de aprendizaje. Los resultados de estas herramientas varían y son difíciles de medir en términos de calidad. En este documento, analizamos los problemas que rodean la tecnología educativa en la educación superior

Predictability of extratropical upper-tropospheric circulation in the Southern Hemisphere by its main modes of variability

The predictability and forecast skill of the models participating in the Climate Historical Forecast Project (CHFP) database is assessed through evaluating the representation of the upper-tropospheric extratropical circulation in the Southern Hemisphere (SH) in winter and summer and its main modes of variability. In summer, the predictability of 200-hPa geopotential height anomalies mainly comes from the ability of the multimodel ensemble mean (MMEM) to forecast the first three modes of interannual variability with high fidelity. The MMEM can reproduce not only the spatial patterns of these modes but also their temporal evolution. On the other hand, in JJA only the second and fourth modes of variability are predictable by the MMEM. These seasonal differences in the performance of the MMEM seem to be related to the role that the sea surface temperature (SST) anomalies have in influencing the variability of each mode. Accordingly, modes that are strongly linked to tropical SST anomalies are better forecast by the MMEM and show less spread among models. The analysis of both 2-m temperature and precipitation anomalies in the SH associated with the predictable modes reveals that DJF predictable modes are accompanied by significant temperature anomalies. In particular, temperatures at polar (tropical) latitudes are significantly correlated with the first (second) mode. Furthermore, these links obtained with observations are also well forecast by the MMEM and can help to improve seasonal forecast of climate anomalies in those regions with low skill.Fil: Osman, Marisol. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Vera, Carolina Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentin

Higher Independence

We study higher analogues of the classical independence number on $\omega$. For $\kappa$ regular uncountable, we denote by $i(\kappa)$ the minimal size of a maximal $\kappa$-independent family. We establish ZFC relations between $i(\kappa)$ and the standard higher analogues of some of the classical cardinal characteristics, e.g. $\mathfrak{r}(\kappa)\leq\mathfrak{i}(\kappa)$ and $\mathfrak{d}(\kappa)\leq\mathfrak{i}(\kappa)$. For $\kappa$ measurable, assuming that $2^\kappa=\kappa^+$ we construct a maximal $\kappa$-independent family which remains maximal after the $\kappa$-support product of $\lambda$ many copies of $\kappa$-Sacks forcing. Thus, we show the consistency of $\kappa^+=\mathfrak{d}(\kappa)=\mathfrak{i}(\kappa)<2^\kappa$. We conclude the paper with interesting open questions and discuss difficulties regarding other natural approaches to higher independence

Drosophila Chromosomal Polymorphism: From Population Aspects to Origin Mechanisms of Inversions

High rates of chromosomal rearrangements are remarkably abundant in Drosophila Fallén, 1832 (Insecta, Diptera) genus, highlighting the paracentric inversions. Since different species of this genus are paradigms for genetics, evolutionary, and population studies, polymorphism analyses for chromosomal inversions have provided basic knowledge for beautiful biological questions. Chromosomal inversions suppress meiotic recombination and thus, natural selection can act to preserve favorable gene complexes. Analyses of natural and laboratory populations show that these polymorphisms provide adaptive advantages to their carriers in relation to diverse factors, such as niche exploration and climatic factors. In addition, due to their monophyletic origin, they also serve as genetic markers for the construction of unrooted phylogenies. With the increasing domain of molecular techniques and genome sequencing, factors such as the reuse of breakpoints by different inversions and the mechanisms that give rise to these polymorphisms have been exploited with scientific refinement. These analyses show the presence of regions that are hot spots for breakpoints, fitting the fragile breakage chromosomal evolution model, as well as the involvement of transposition elements at the origin of chromosomal inversions

The influence of the Andes mountains on the South American low-level flow

[1] A dry, hydrostatic, three-dimensional primitive equation model is used to evaluate the mechanical effect of the Andes mountains on the South American low-level flow (LLF). The model simulations reproduce the evolution of a baroclinic wave over the continent under winter and summer conditions. In both seasons as a consequence of the interaction between the basic flow and the Andes, northerly LLF was reproduced east of the Andes which resembles the main characteristics of the observed flow. Moreover, seasonal changes of cyclone activity have a significant impact on the location of maximum LLF and its alignment, which exhibits a NW-SE orientation during winter and more meridional orientation in the warm season.Fil: Campetella, Claudia Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Vera, Carolina Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentin

Análisis de la usabilidad en el portal web CDISCOUNT Colombia

Este trabajo de investigación tiene como objetivo identificar las falencias relacionadas con el uso de herramientas involucradas en la experiencia de usuario durante el proceso de compra en el portal web Cdiscount Colombia, con el fin de plantear recomendaciones de mejora -- Como metodología para el desarrollo del mismo se realizó una investigación mixta con clientes y no clientes del portal web, mediante el uso de las herramientas como Eye tracker, entrevista en profundidad, paseo cognitivo y evaluación heurística, para conocer la interacción de los usuarios con el portal web y obtener hallazgos para su posterior análisis -- El mayor aporte del trabajo de investigación es el diagnóstico de la usabilidad del portal web Cdiscount Colombia y la propuesta de mejoras con el fin de documentar los hallazgos y así presentarlos como punto de partida en el diseño o rediseño de otros portales web para poder ofrecerles a los consumidores una experiencia de usuario positiva con el fin de lograr una posible recompr

Summer precipitation variability over South America on long and short intraseasonal timescales

A dipole pattern in convection between the South Atlantic convergence zone and the subtropical plains of southeastern South America characterizes summer intraseasonal variability over the region. The dipole pattern presents two main bands of temporal variability, with periods between 10 and 30Â days, and 30 and 90Â days; each influenced by different large-scale dynamical forcings. The dipole activity on the 30--90-day band is related to an eastward traveling wavenumber-1 structure in both OLR and circulation anomalies in the tropics, similar to that associated with the Madden--Julian oscillation. The dipole is also related to a teleconnection pattern extended along the South Pacific between Australia and South America. Conversely, the dipole activity on the 10--30-day band does not seem to be associated with tropical convection anomalies. The corresponding circulation anomalies exhibit, in the extratropics, the structure of Rossby-like wave trains, although their sources are not completely clear