4,397 research outputs found

    Evaluación del sesgo en las clasificaciones taxonómicas del índice cefálico

    Get PDF
    El índice cefálico (ic) ha sido ampliamente utilizado para establecer categorías taxonómicas humanas. Aunque su significado biológico ha sido discutido, pocos trabajos han analizado la relación numérica del índice y sus clasificaciones. Aquí se aborda uno de los sesgos introducidos por la transformación en categorías de clase (braquicefalia, mesocefalia y dolicocefalia) de la distribución continua del ic, se analiza el efecto que tiene en la varianza poblacional y en la densidad de los datos. Por medio de la Howells World Data Set recurrimos al coeficiente de determinación como estimador de la cantidad de información que se conserva posterior a la trans- formación categórica del ic. Nuestros resultados indican que las clasificaciones del ic son un reducto de la variabilidad biológica craneal de las poblaciones humanas. La adopción de modelos no lineales hiperdimensionales y multivariados representa un mejor acercamiento a la covariación de las formas biológicas.The cephalic index (ic) has been widely used as one of the higher profile tools to establish human taxonomy categories. Although it has been discussed the biological sense of the cephalic index, few studies analyzed the mathematics relations of the ratio and their classifications. In this paper, we address one of the biases introduced by the transformation into class categories (brachycephaly, mesocephaly and dolichocephaly) of the continuous distribution of IC, analyzing the effect in the population variance and the density of the data. Thus, we used Howells World Data Set for determination coefficient as an estimate of amount of information retained after processing IC categories. Our results indicate that the ratings of the IC are a haven of cranial biological variability of human populations. The adoption of hyperdimensional non-linear and multivariate models represents a better approach to the covariance of biological forms.Fil: Gomez Valdes, Jorge A.. Universidad Nacional Autónoma de México; MéxicoFil: Quinto Sanchez, Mirsha Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

    Galaxy interactions in IllustrisTNG-100, I: The power and limitations of visual identification

    Get PDF
    We present a sample of 446 galaxy pairs constructed using the cosmological simulation IllustrisTNG-100 at z = 0, with M_(FoF,dm)=10¹¹−10^(13.5) M⊙. We produce ideal mock SDSS g-band images of all pairs to test the reliability of visual classification schema employed to produce samples of interacting galaxies. We visually classify each image as interacting or not based on the presence of a close neighbour, the presence of stellar debris fields, disturbed discs, and/or tidal features. By inspecting the trajectories of the pairs, we determine that these indicators correctly identify interacting galaxies ∼45 per cent of the time. We subsequently split the sample into the visually identified interacting pairs (VIP; 38 pairs) and those which are interacting but are not visually identified (nonVIP; 47 pairs). We find that VIP have undergone a close passage nearly twice as recently as the non-VIP, and typically have higher stellar masses. Further, the VIP sit in dark matter haloes that are approximately 2.5 times as massive, in environments nearly 2 times as dense, and are almost a factor of 10 more affected by the tidal forces of their surroundings than the nonVIP. These factors conspire to increase the observability of tidal features and disturbed morphologies, making the VIP more likely to be identified. Thus, merger rate calculations which rely on stellar morphologies are likely to be significantly biased toward massive galaxy pairs which have recently undergone a close passage

    A wake-integral method for drag prediction

    Full text link
    This paper describes the theoretical development and implementation issues of a far field induced drag extraction tool based on the Maskell integral. Far field methods provide an alternative to classical near field approach, offering the possibility of decompose drag contributions based on their physical source and improves prediction accuracy on coarse meshes. Instead of classical triangulation of intersection nodes contained in the cutting plane, a more regular adaptive mesh is implemented in order to improve flow reconstruction smoothness and accuracy. Both meshes results are compared and the influence of generation parameters of the bidimensional adaptive mesh is discussed. Numerical diffusion plays a major role in vortex decay, and because of that phenomena, a correction factor is needed in order to back as much as possible the cutting plane without loosing precision. Finally, Onera M6 tests are conducted, showing acceptable precision in drag prediction until seven or more chords downstream

    The insulator factor CTCF controls MHC class II gene expression and is required for the formation of long-distance chromatin interactions

    Get PDF
    Knockdown of the insulator factor CCCTC binding factor (CTCF), which binds XL9, an intergenic element located between HLA-DRB1 and HLA-DQA1, was found to diminish expression of these genes. The mechanism involved interactions between CTCF and class II transactivator (CIITA), the master regulator of major histocompatibility complex class II (MHC-II) gene expression, and the formation of long-distance chromatin loops between XL9 and the proximal promoter regions of these MHC-II genes. The interactions were inducible and dependent on the activity of CIITA, regulatory factor X, and CTCF. RNA fluorescence in situ hybridizations show that both genes can be expressed simultaneously from the same chromosome. Collectively, the results suggest a model whereby both HLA-DRB1 and HLA-DQA1 loci can interact simultaneously with XL9, and describe a new regulatory mechanism for these MHC-II genes involving the alteration of the general chromatin conformation of the region and their regulation by CTCF

    Complex-Variable Sliding-Mode Control of Instantaneous Complex Energy and Power for Grid-Tied Inverter

    Get PDF
    A complex-variable sliding-mode control (SMC) algorithm is proposed to govern inverters interfacing renewable energy sources (RESs) with the electrical grid. It is conceived to control the instantaneous energy stored in the passive components of the system and its rate of change, as well as the instantaneous reactive energy and power exchanged with the grid. The stability of the resulting closed-loop system is analyzed, and tuning of the designed SMC algorithm is also tackled. In addition, the design and tuning of a nonlinear observer estimating the renewable power supplied to the DC link are addressed. The overall control scheme obtained by combining the proposed complex-variable SMC algorithm with such observer is assessed in simulation, demonstrating its outstanding tracking performance and high robustness in presence of large parameter variations.Co-financed by the MICIN/AEI/10.13039/501100011033 (project code PID2020-115484RA-I00), by the Basque Government under research grant IT1644-22, by the Universidad Nacional del Sur (UNS), and by the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)

    Improvement of diabetic retinopathy screening of diabetic patients seen at the Internal Medicine Clinic​​

    Get PDF
    Diabetic retinopathy (DR) is a leading cause of vision loss globally. The International Diabetes Federation (IDF) estimated the global population with diabetes to be 463 million in 2019 and 700 million in 2045. Retinopathy is a highly specific neurovascular complication of both type 1 and types 2 diabetes, and the prevalence strongly correlates to both the duration of diabetes and the level of glycemic control. Regular follow-up with early detection and treatment of vision-threatening retinopathy enables the prevention of up to 98% of visual loss due to diabetic retinopathy

    Analytical description of optical vortices generated by discretized vortex-producing lenses

    Get PDF
    In this article, a general analytical treatment (any topological charge - any number of discretization levels) for the diffraction of a Gaussian beam through a discretized vortex-producing lens is presented. In the proposal, the field is expressed as a sum of Kummer beams with different amplitudes and topological charges, which are focalized at different planes on the propagation axis. Likewise, it is demonstrated that characteristics of diffracted light can be modified by tuning the parameters of the setup. Vortex lines are analyzed to understand the internal mechanism of measurable topological charges that appear in specific planes, apparently violating topological charge conservation. Conservation of the topological charge is verified and theoretical predictions are supported by experiments.Fil: Rumi, Gonzalo Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Ópticas. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones Ópticas. Universidad Nacional de La Plata. Centro de Investigaciones Ópticas; ArgentinaFil: Actis, Daniel Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Ópticas. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones Ópticas. Universidad Nacional de La Plata. Centro de Investigaciones Ópticas; ArgentinaFil: Amaya Robayo, Dafne Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Ópticas. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones Ópticas. Universidad Nacional de La Plata. Centro de Investigaciones Ópticas; ArgentinaFil: Gomez, Jorge A.. Politécnico Colombiano Jaime Isaza Cadavid; ColombiaFil: Rueda, Edgar. Universidad de Antioquia; ColombiaFil: Lencina, Alberto Germán. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentin
    corecore