1,019 research outputs found

    Mathematical and physical techniques of modeling and simulation of pattern recognition in the stock market

    Get PDF
    The following article presents the analysis through mathematical and physical techniques of large databases, which are very common today, due to the large number of variables (especially in the information and physics industry) and the amount of information that results from a process, therefore an analysis is necessary that allows the Decision in a responsible manner, looking for scientific criteria that support said decisions, in our case a database of the forex system will be taken. Initially, a study and calculation of different measurements between the samples and their characteristics will be carried out to make a good prediction of the data and their behavior using different classification methods inspired by basic sciences. Below is an explanation of the techniques based on the analysis of data components and the correlations that exist between the variables, which is a technique widely used in physical processes to determine the correlations between variables

    Estado y prioridades de conservación de los anfibios del departamento del Quindío, Colombia

    Get PDF
    stat i prioritats de conservació dels amfibis del departament del Quindío, Colòmbia En aquest article presentem una avaluació de l’estat i les prioritats de conservació dels amfibis al Quindío amb l’objectiu de proposar accions per conservar-los. Vam generar una llista d’espècies d’amfibis del departament, vam modelar la distribució potencial de les espècies amenaçades amb l’algoritme de màxima entropia de MaxEnt i en vam avaluar la representativitat en el Sistema Departamental d’Àrees Protegides del Quindío (SIDAPQ). A més a més, vam prioritzar les àrees per a la conservació dels amfibis amb l’algoritme ILV4 adjacency de ConsNet. Vam registrar 45 espècies d’amfibis, el 24,4% de les quals es troben incloses en alguna categoria d’amenaça de la Llista Vermella de la UICN. Els amfibis amenaçats van presentar una distribució i uns registres superiors al 50% dins del SIDAPQ. Les àrees prioritzades per assolir objectius de representativitat del 10, 20 i 30% de la distribució dels amfibis estan totalment fragmentades i només tenen el 30% de la distribució prioritzada al SIDAPQ. Davant d’aquest escenari, proposem una estratègia de conservació de caràcter paisatgístic que inclogui els agroecosistemes, tractant de mantenir-ne l’heterogeneïtat i eliminant-ne o disminuint-ne els factors d’amenaça.Conservation status and priorities of amphibians from the Quindío Department, Colombia We reviewed the conservation status and priorities for amphibians from the Quindío region of Colombia, with the purpose of proposing conservation actions. We modeled the potential distribution of threatened species using the maximum entropy algorithm in MaxEnt and evaluated representability in the Departmental System of Protected Areas for Quindío (Spanish acronym: SIDAPQ). We prioritized areas for amphibian conservation using the algorithm ILV4 adjacency in ConsNet. We recorded 45 species, 24.4% of which are included in threatened categories on the IUCN Red List. Over 50% of the distribution and records of the threatened amphibians occurred inside the SIDAPQ. Prioritized areas to achieve representation goals of 10, 20 and 30% of amphibian distribution are highly fragmented and have only approximately 30% of prioritized distribution in the SIDAPQ. Considering this scenario we propose a conservation strategy on the landscape level that includes agroecosystems, maintaining their heterogeneity and eliminating or mitigating threat factors.En este artículo presentamos una evaluación del estado y prioridades de conservación de los anfibios en el Quindío con el objetivo de proponer acciones para su conservación. Generamos una lista de especies de anfibios del departamento, modelamos la distribución potencial de las especies amenazadas con el algoritmo de máxima entropía de MaxEnt y evaluamos su representatividad en el Sistema Departamental de Áreas Protegidas del Quindío (SIDAPQ). Además, priorizamos las áreas para la conservación de los anfibios con el algoritmo ILV4 adjacency de ConsNet. Registramos 45 especies de anfibios, el 24,4% de las cuales se encuentran incluidas en alguna categoría de amenaza de la Lista Roja de la UICN. Los anfibios amenazados presentaron una distribución y unos registros superiores al 50% dentro del SIDAPQ. Las áreas priorizadas para alcanzar los objetivos de representatividad del 10, 20 y 30% de la distribución de los anfibios están altamente fragmentadas y sólo tienen el 30% de la distribución priorizada en el SIDAPQ. Ante este escenario, proponemos una estrategia de conservación de carácter paisajístico que incluya los agroecosistemas, tratando de mantener su heterogeneidad y eliminando o mitigando los factores de amenaza

    Partisanship and the Pandemic: How and Why Americans Followed Party Cues on COVID-19

    Get PDF
    The United States underperformed its potential in responding to the COVID-19 pandemic. Using original survey data from April 2020 to March 2022, we show that political partisanship may have contributed to this inconsistent response by distinguishing elites and citizens who took the crisis seriously from those who did not. This division was not inevitable; when the crisis began, Democrats and Republicans differed little in their viewpoints and actions. However, partisans increasingly diverged when their preferred political leaders provided them with opposing cues. We outline developments in party politics over the last half-century that contributed to partisan division on COVID-19, most centrally an anti-expertise bias among Republicans. Accordingly, Republicans' support for mitigation measures, perception of severity of COVID-19, and support for vaccines gradually decreased after the initial outbreak. Partisan differences also showed up at the state level; Trump's vote share in 2016 was negatively associated with mask use and positively associated with COVID-19 infections. Diverging elite cues provided fertile ground for the partisan pandemic, underscoring the importance of political accountability, even in an era of polarization

    Etiology of chronic urticaria: the Ecuadorian experience

    Get PDF
    Background: The purpose of this study was to identify chronic urticaria (CU) etiologies and treatment modalities in Ecuador. We propose that the sample distribution fits the expected one, and that there is an association between the etiology and its treatment. Methods: We performed a retrospective study involving 112 patients diagnosed with CU using a Checklist for a complete chronic urticaria medical history. Demographic and clinical variables were collected. The etiology of CU was classified using the EAACI/GA2LEN/EDF/WAO guideline. Descriptive analyses were performed for demographical and clinical variables. Chi square tests were applied to analyze the fit of distribution and the independence of variables. P values less than 0.05 were considered significant. Results: Among all the patients, 76.8% were diagnosed with chronic spontaneous urticaria (CSU), of which 22.3% had a known etiology or possible exacerbating condition. Food allergy was identified as the most common accompanying condition in patients with CSU (10.7%) (p < 0.01).. On the other hand, 23.2% inducible urticarias (CIndU) were indentified; dermographism was the most common (10.7%) (p < 0.01). Regarding treatment regimens, sg-H1-antihistamines alone represented the highest proportion (44.6%). The combination of any H1-antihistamine plus other drug was a close second (42.0%) (p < 0.01). Almost 48% of CSUs of unknown etiology were treated with any antihistamine plus another drug. In patients with known etiology, sg-antihistamines alone (44.0%) was the most common management. In addition, 53.8% of CIndUs were treated with sg-antihistamines alone. Though, these associations were not statistically significant. Conclusion: CSU is the most frequent subtype of CU. Modern non-sedating antihistamines in licensed doses are the drug of choice. Nevertheless, a great proportion of patients require the addition of another type of medication

    Effect of floor type on the performance, physiological and behavioural responses of finishing beef steers

    Get PDF
    peer-reviewedBackground:The study objective was to investigate the effect of bare concrete slats (Control), two types of mats [(Easyfix mats (mat 1) and Irish Custom Extruder mats (mat 2)] fitted on top of concrete slats, and wood-chip to simulate deep bedding (wood-chip placed on top of a plastic membrane overlying the concrete slats) on performance, physiological and behavioral responses of finishing beef steers. One-hundred and forty-four finishing steers (503 kg; standard deviation 51.8 kg) were randomly assigned according to their breed (124 Continental cross and 20 Holstein–Friesian) and body weight to one of four treatments for 148 days. All steers were subjected to the same weighing, blood sampling (jugular venipuncture), dirt and hoof scoring pre study (day 0) and on days 23, 45, 65, 86, 107, 128 and 148 of the study. Cameras were fitted over each pen for 72 h recording over five periods and subsequent 10 min sampling scans were analysed. Results: Live weight gain and carcass characteristics were similar among treatments. The number of lesions on the hooves of the animals was greater (P < 0.05) on mats 1 and 2 and wood-chip treatments compared with the animals on the slats. Dirt scores were similar for the mat and slat treatments while the wood-chip treatment had greater dirt scores. Animals housed on either slats or wood-chip had similar lying times. The percent of animals lying was greater for animals housed on mat 1 and mat 2 compared with those housed on concrete slats and wood chips. Physiological variables showed no significant difference among treatments. Conclusions: In this exploratory study, the performance or welfare of steers was not adversely affected by slats, differing mat types or wood-chip as underfoot material

    Principal component and Voronoi skeleton alternatives for curve reconstruction from noisy point sets

    Get PDF
    Surface reconstruction from noisy point samples must take into consideration the stochastic nature of the sample -- In other words, geometric algorithms reconstructing the surface or curve should not insist in following in a literal way each sampled point -- Instead, they must interpret the sample as a “point cloud” and try to build the surface as passing through the best possible (in the statistical sense) geometric locus that represents the sample -- This work presents two new methods to find a Piecewise Linear approximation from a Nyquist-compliant stochastic sampling of a quasi-planar C1 curve C(u) : R → R3, whose velocity vector never vanishes -- One of the methods articulates in an entirely new way Principal Component Analysis (statistical) and Voronoi-Delaunay (deterministic) approaches -- It uses these two methods to calculate the best possible tape-shaped polygon covering the planarised point set, and then approximates the manifold by the medial axis of such a polygon -- The other method applies Principal Component Analysis to find a direct Piecewise Linear approximation of C(u) -- A complexity comparison of these two methods is presented along with a qualitative comparison with previously developed ones -- It turns out that the method solely based on Principal Component Analysis is simpler and more robust for non self-intersecting curves -- For self-intersecting curves the Voronoi-Delaunay based Medial Axis approach is more robust, at the price of higher computational complexity -- An application is presented in Integration of meshes originated in range images of an art piece -- Such an application reaches the point of complete reconstruction of a unified mes

    Neutrino-less Double Beta Decay and Particle Physics

    Full text link
    We review the particle physics aspects of neutrino-less double beta decay. This process can be mediated by light massive Majorana neutrinos (standard interpretation) or by something else (non-standard interpretations). The physics potential of both interpretations is summarized and the consequences of future measurements or improved limits on the half-life of neutrino-less double beta decay are discussed. We try to cover all proposed alternative realizations of the decay, including light sterile neutrinos, supersymmetric or left-right symmetric theories, Majorons, and other exotic possibilities. Ways to distinguish the mechanisms from one another are discussed. Experimental and nuclear physics aspects are also briefly touched, alternative processes to double beta decay are discussed, and an extensive list of references is provided.Comment: 96 pages, 38 figures. Published versio

    Measuring the speed of light and the moon distance with an occultation of Mars by the Moon: a Citizen Astronomy Campaign

    Get PDF
    In July 5th 2014 an occultation of Mars by the Moon was visible in South America. Citizen scientists and professional astronomers in Colombia, Venezuela and Chile performed a set of simple observations of the phenomenon aimed to measure the speed of light and lunar distance. This initiative is part of the so called "Aristarchus Campaign", a citizen astronomy project aimed to reproduce observations and measurements made by astronomers of the past. Participants in the campaign used simple astronomical instruments (binoculars or small telescopes) and other electronic gadgets (cell-phones and digital cameras) to measure occultation times and to take high resolution videos and pictures. In this paper we describe the results of the Aristarchus Campaign. We compiled 9 sets of observations from sites separated by distances as large as 2,500 km. We achieve at measuring the speed of light in vacuum and lunar distance with uncertainties of few percent. The goal of the Aristarchus Campaigns is not to provide improved values of well-known astronomical and physical quantities, but to demonstrate how the public could be engaged in scientific endeavors using simple instrumentation and readily available technological devices. These initiatives could benefit amateur communities in developing countries increasing their awareness towards their actual capabilities for collaboratively obtaining useful astronomical data. This kind of exercises would prepare them for facing future and more advanced observational campaigns where their role could be crucial.Comment: 21 pages, 10 figures, 3 tables. An abridged and more general version of this paper was accepted for publication in Communicating Astronomy with the Public Journal (http://www.capjournal.org
    corecore