60 research outputs found

    A curricular approach to develop autonomies from the mathematics and scientific education

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    The purpose of this work is to highlight how the current Spanish education system supports the development of both scientific and mathematic competences. We understand these competences as the set of skills and capabilities needed to use mathematics or science when the situation requires. For that purpose, we have carried out a curricular didactic analysis of the current regulations in Andalusia. This analysis intends to reveal how the new educational systems emphasize the development of the formative character of teaching-learning processes, which has been overshadowed by the functional and the instrumental characters in Science and Mathematics Education. The findings of the research show that the objectives set out in the law are aimed at developing in students a number of attributes such as personal autonomy, creativity, tolerance, empathy, critical spirit, etc. From our point of view, all of these attributes contribute to developing the students' formative character. Besides, the analysis shows that course contents are not presented as an end in itself, but as a means for students to acquire these attributes and be whole human beings. Finally, it can be inferred from the analysis that both the methodological guidance and the evaluation criteria highlight the need to educate citizens to be capable of adapting to the environment and positively transforming it. Ultimately, promoting teaching-learning processes where scientific and mathematic competences are developed, educating students to be intellectually, socially and morally autonomous.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.“Criterios e instrumentos de evaluación de unidades de enseñanza y aprendizaje” (PPIT.UMA.B1.2017/16) financiado por la Universidad de Málaga en la convocatoria de 2017-2018

    Hill Problem Analytical Theory to the Order Four. Application to the Computation of Frozen Orbits around Planetary Satellites

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    Frozen orbits of the Hill problem are determined in the double averaged problem, where short and long period terms are removed by means of Lie transforms. The computation of initial conditions of corresponding quasi periodic solutions in the non-averaged problem is straightforward for the perturbation method used provides the explicit equations of the transformation that connects the averaged and non-averaged models. A fourth order analytical theory reveals necessary for the accurate computation of quasi periodic, frozen orbits

    Invariant tori in the lunar problem

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    Theorems on the existence of invariant KAM tori are established for perturbations of Hamiltonian systems which are circle bundle ows. By averaging the perturbation over the bundle ow one obtains a Hamiltonian system on the orbit (quotient) space by a classical theorem of Reeb. A non-degenerate critical point of the system on the orbit space gives rise to a family of periodic solutions of the perturbed system. Conditions on the critical points are given which insure KAM tori for the perturbed ow. These general theorems are used to show that the near circular periodic solutions of the planar lunar problem are orbitally stable and are surrounded by KAM 2-tori. For the spatial case it is shown that there are periodic solutions of two types, either near circular equatorial, that is, the infinitesimal particle moves close to the plane of the primaries following near circular trajectories and the other family where the ifinitesimal particle moves along the axis perpendicular to the plane of the primaries following near rectilinear trajectories. We prove that the two solutions are elliptic and are surrounded by invariant 3-tori applying a recent theorem of Han, Li, and Yi. In the spatial case a second averaging is performed, and the corresponding or- bit space (called the twice-reduced space) is constructed. The flow of the averaged Hamiltonian on it is given and several families of invariant 3-tori are determined using Han, Li, and Yi Theorem

    El "status" socio-académico de las matemáticas : un punto de referencia singular

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    Los resultados de diferentes encuestas entre estudiantes de educación básica y secundaria muestran que las matemáticas se perciben como una materia con un estatus especial, en comparación con el resto de las disciplinas; se enfatiza su importancia, utilidad académica, dificultad y aburrimiento. Este panorama cambia un poco según los niveles educativos, el tipo de estudios, los cursos, etc., pero el estado socio-académico diferenciado persiste

    Proyecto Rincón del encuentro

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    El proyecto ¨El rincón del encuentro¨ nos habla sobre como promover el contacto intergeneracional entre los jóvenes y personas mayores en el municipio de Montalban (Teruel)

    Association between preoperative levels of 25-hydroxyvitamin D and hospital-acquired infections after hepatobiliary surgery: A prospective study in a third-level hospital

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    Introduction Evidence implicates vitamin D deficiency in poorer outcomes and increased susceptibility to hospital-acquired infections (HAIs). This study examined the association between serum vitamin D levels and HAIs in a population of hepatobiliary surgery patients. Methods Participants in this prospective analytical observational study were patients who underwent hepatobiliary surgery in a tertiary hospital in Aragon, Spain, between February 2018 and March 2019. Vitamin D concentrations were measured at admission and all nosocomial infections during hospitalization and after discharge were recorded. Results The mean 25-hydroxyvitamin D concentration of the study population (n = 301) was 38.56 nmol/L, which corresponds to vitamin D deficiency. Higher vitamin D concentrations were associated with a decreased likelihood of developing a HAI in general (p = 0.014), and in particularly surgical site infection (p = 0.026). The risk of HAI decreased by 34% with each 26.2-nmol/L increase in serum vitamin D levels. Conclusions Vitamin D levels may constitute a modifiable risk factor for postoperative nosocomial infections in hepatobiliary surgery patients

    Transition state theory for laser-driven reactions

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    Recent developments in Transition State Theory brought about by dynamical systems theory are extended to time-dependent systems such as laser-driven reactions. Using time-dependent normal form theory, we construct a reaction coordinate with regular dynamics inside the transition region. The conservation of the associated action enables one to extract time-dependent invariant manifolds that act as separatrices between reactive and non-reactive trajectories and thus make it possible to predict the ultimate fate of a trajectory. We illustrate the power of our approach on a driven H´enon-Heiles system, which serves as a simple example of a reactive system with several open channels. The present generalization of Transition State Theory to driven systems will allow one to study processes such as the control of chemical reactions through laser pulses

    Infección del sitio quirúrgico en cirugía hepatobiliopancreática y su relación con la concentración sérica de vitamina D

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    Introducción La relación entre las infecciones nosocomiales en pacientes quirúrgicos y la vitamina D ha sido estudiada por algunos autores. Sin embargo, hasta la fecha no existe ningún estudio realizado sobre pacientes de cirugía hepatobiliar. El objetivo de nuestro trabajo es estudiar la infección del sitio quirúrgico (ISQ) en la unidad de cirugía hepatobiliar, y valorar su relación con la concentración sérica de vitamina D. Métodos Se llevó a cabo un estudio analítico observacional de pacientes sucesivos intervenidos en la unidad de cirugía hepatobiliar de nuestro centro durante un año. Se incluyeron las intervenciones relativas a enfermedad biliar, pancreática y hepática. Se determinaron los niveles de vitamina D al ingreso, así como las ISQ de tipo superficial, profunda y órgano-cavitaria diagnosticadas durante el estudio. El seguimiento del paciente se realizó durante al menos un mes tras la cirugía, dependiendo de la enfermedad. La estadística se realizó mediante el programa estadístico R v.3.1.3. Resultados La muestra quedó constituida por 321 pacientes, de los cuales el 25, 8% presentó ISQ a expensas fundamentalmente de las infecciones órgano-cavitarias que presentaron una incidencia del 24, 3%. Concentraciones séricas superiores a 33, 5 nmol/l demostraron reducir en un 50% el riesgo de ISQ. Conclusiones Las concentraciones elevadas de vitamina D en sangre demostraron ser un factor protector frente a las ISQ (OR: 0, 99). Nuestros resultados sugieren una relación directa entre la concentración sérica de vitamina D y la ISQ, justificando la realización de nuevos estudios prospectivos. Introduction: While several studies have examined the correlation between vitamin D concentrations and post-surgical nosocomial infections, this relationship has yet to be characterized in hepatobiliary surgery patients. We investigated the relationship between serum vitamin D concentration and the incidence of surgical site infection (SSI) in patients in our hepatobiliary surgery unit. Methods: Participants in this observational study were 321 successive patients who underwent the following types of interventions in the hepatobiliary surgery unit of our center over a 1-year period: cholecystectomy, pancreaticoduodenectomy, total pancreatectomy, segmentectomy, hepatectomy, hepaticojejunostomy and exploratory laparotomy. Serum vitamin D levels were measured upon admission and patients were followed up for 1 month. Mean group values were compared using a Student's T-test or Chi-squared test. Statistical analyses were performed using the Student's T-test, the Chi-squared test, or logistic regression models. Results: Serum concentrations >33.5 nmol/l reduced the risk of SSI by 50%. Out of the 321 patients analyzed, 25.8% developed SSI, mainly due to organ-cavity infections (incidence, 24.3%). Serum concentrations of over 33.5 nmol/l reduced the risk of SSI by 50%. Conclusions: High serum levels of vitamin D are a protective factor against SSI (OR, 0.99). Our results suggest a direct relationship between serum vitamin D concentrations and SSI, underscoring the need for prospective studies to assess the potential benefits of vitamin D in SSI prevention

    Prevalence and genetic characteristics of Staphylococcus aureus CC398 isolates from invasive infections in spanish hospitals, focusing on the livestock-independent CC398-MSSA clade

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    Background: Livestock-associated (LA)-CC398-MRSA is closely related to pigs, being unfrequently detected in human invasive infections. CC398-MSSA is emerging in human invasive infections in some countries, but genetic and epidemiological characteristics are still scarcely reported. Objectives: To determine the prevalence of Staphylococcus aureus (SA) CC398, both MRSA and MSSA, among blood cultures SA isolates recovered in Spanish hospitals located in regions with different pig-farming densities (PD) and characterize the recovered isolates. Methods: One thousand twenty-two SA isolates (761 MSSA, 261 MRSA) recovered from blood cultures during 6–12 months in 17 Spanish hospitals (2018–2019) were studied. CC398 lineage identification, detection of spa-types, and antibiotic resistance, virulence and human immune evasion cluster (IEC) genes were analyzed by PCR/sequencing. Results: Forty-four CC398-MSSA isolates (4.3% of SA; 5.8% of MSSA) and 10 CC398-MRSA isolates (1% of SA; 3.8% of MRSA) were detected. Eleven spa-types were found among the CC398-MSSA isolates with t571 and t1451 the most frequent spa-types detected (75%). Most of CC398-MSSA isolates were Immune-Evasion-Cluster (IEC)-positive (88.6%), tetracycline-susceptible (95.5%) and erythromycin/clindamycin–inducible-resistant/erm(T)-positive (75%). No statistical significance was detected when the CC398-MSSA/MSSA rate was correlated to PD (pigs/km2) (p = 0.108). On the contrary, CC398-MRSA isolates were all IEC-negative, predominately spa-t011 (70%), and the CC398-MRSA/MRSA rate was significantly associated to PD (p < 0.005). Conclusion: CC398-MSSA is an emerging clade in invasive infections in Spanish hospitals. CC398-MRSA (mostly t011) and CC398-MSSA (mostly t571 and t1451) show important differences, possibly suggesting divergent steps in host-adaptation evolutionary processes. While CC398-MRSA is livestock-associated (lacking IEC-system), CC398-MSSA seems to be mostly livestock-independent, carrying human-adaptation markers.
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