2,616 research outputs found
Compound orbits break-up in constituents: an algorithm
In this paper decomposition of periodic orbits in bifurcation diagrams are
derived in unidimensional dynamics system , being an
unimodal function. We proof a theorem which states the necessary and sufficient
conditions for the break-up of compound orbits in their simpler constituents. A
corollary to this theorem provides an algorithm for the computation of those
orbits. This process closes the theoretical framework initiated in (Physica D,
239:1135--1146, 2010)
Advanced architectural descriptors in foams: novel 3D computational methods
This work presents 3D computational strategies aimed at providing foam de-structuration of the basic components of a cellular material (struts and cell walls) offering the possibility of analysing separately the structural elements that play an important role in the physical properties of thee materials. Two different methodologies have been used depending on the topological similarities existing between the struts and cell walls: 3D erosion-dilation procedure (thick struts) and solid classification algorithm (thin struts). In a second step, analysis of cell walls is performed in order to show the advantages of analysing separately the two foams components. Particularly, cell wall thickness distribution reveals differences that could not be found prior to the de-structuration
De la metacognición a la comprensión narrativa en la primera infancia
Un factor decisivo que determina el saber consciente, aquellocorrelacionado con una alta capacidad intelectual, se logra por el desarrollo de la metacompetencia comunicativa, que atañe a los procesos autorregulatorios de orden cognitivo, y que se fortalecen por la enseñanza de la comprensión narrativa desde la primera infancia.Aun cuando el niño nohaya accedido al dominio del mecanismo de la decodificación o su lateralidad no esté bien definida, este objetivo educacional de importancia capital, le posibilita no sólo a traducir imágenes visuales a sonidos, sino decodificar palabras desconocidas o procesar su significado; realizar inumerables operaciones metacognitivas que hacen posible el desarrollode su pensamiento, la comunicación, la respuesta a un estímulo que implican actos conscientes o automáticos, y el encuentro de su cultura, relacionada al contexto socio-espacial inmediato.
Aprender por tanto, a leer y escribir desde la infancia, es “algo más que enseñar letras”, es una actividad intelectual y cultural que da sentido y orientación a los aprendizajes esperados. El aprendizaje se relaciona con un cambio en las conexiones sinápticas de las neuronas, ya sea por asociaciones con un grupo de neuronas específico o con la generación de nuevas sinapsis que originan una respuesta en función de cambios internos del cerebro o por los que provienen del entorno. Si entendemos que los niños van apropiándose de significados a partir de imágenes y sonidos, así como experiencias gratas y lúdicas, estaremos comprendiendo el papel de los procesos cognitivos que operan sobre el pensamiento, es decir la metacognición, base de la alfabetización, proceso natural de iniciación a la lectura y la escritura; camino que se convierte en un hábito de vida para el hombre del futuro con sensibilidad comunitaria y profundo sentido trascendente
PERCEPÇÕES DOS PROFESSORES AICLE SOBRE A COMPETÊNCIA INTERCULTURAL NO ENSINO BÁSICO
CLIL (Content and Language Integrated Learning) includes the development of intercultural awareness as one of its main axes. Therefore, the main objective of this research is to examine the perceptions that CLIL teachers have regarding Intercultural Competence (IC) and the elements that contribute to its development. Through an open-question survey, we analysed the opinions of 59 Primary Education CLIL teachers from Cordoba. For the analysis of the qualitative data, Atlas.ti has been used on its two options: the textual and the conceptual analysis, thus generating the corresponding networks. On the other hand, SPSS v. 21 was used for the quantitative data analysis. The results show that CLIL teachers define IC closely linked to linguistic competence, and that communicative activities play an important role.En el enfoque AICLE (Aprendizaje Integrado de Contenidos y Lenguas Extranjeras), el desarrollo de la conciencia intercultural adquiere un protagonismo esencial. Por ello, conocer la percepción que el profesorado AICLE tiene en relación a la Competencia Intercultural (CI) y los elementos que contribuyen a su desarrollo se convierte en el objetivo fundamental de esta investigación. Mediante un cuestionario abierto se han analizado las opiniones de 59 profesores de Córdoba que trabajan con dicho enfoque en Educación Primaria. Para el análisis de los datos cualitativos se ha usado Atlas.ti en sus dos vertientes: el análisis textual y el análisis conceptual, generando las Networks correspondientes. Por otro lado, para el análisis de datos cuantitativos se utilizó el programa SPSS v. 21. Los resultados muestran que el profesorado AICLE define la CI estrechamente vinculada a la competencia lingüística y, por lo tanto, señala que las actividades comunicativas son las que más ayudan a fomentar la CI.No enfoque AICLE (Aprendizagem Integrada de Conteúdos e Línguas Estrangeiras), o desenvolvimento da consciência intercultural adquire um protagonismo essencial. Por isso, conhecer a percepção que os professores AICLE têm com relação à Competência Intercultural (CI) e os elementos que contribuem a seu desenvolvimento torna-se o objetivo fundamental desta pesquisa. Mediante um questionário aberto foram analisadas as opiniões de 59 professores de Córdoba que trabalham com esse enfoque no Ensino Básico. Para a análise dos dados qualitativos utilizou-se o Atlas.ti em suas duas vertentes: a análise textual e a análise conceitual, gerando as Networks correspondentes. Por outro lado, para a análise de dados quantitativos utilizou-se o programa SPSS v. 21. Os resultados mostram que os professores AICLE definem a CI como uma competência estreitamente vinculada à competência linguística e, portanto, salienta que as atividades comunicativas são as que mais ajudam a fomentar a CI
Activity of Ricinus communis (Euphorbiaceae) against Spodoptera frugiperda (Lepidoptera: Noctuidae)
One of the most studied plant species with insecticidal properties is the castor bean Ricinus communis. However, its activity against Spodoptera frugiperda is unclear. Therefore, to determinate the insecticidal and insectistatic activities of methanol, hexane and ethyl acetate extracts of the seeds and leaves of R. communis, castor oil and ricinine were tested at different concentrations against S. frugiperda. This study demonstrated for the first time, that the castor oil and ricinine are active ingredients of R. communis that acts against S. frugiperda and that each of the seed extracts exhibited better insecticidal and insectistatic activity than the leaf extracts. The half maximum larvae viability concentration (LVC50) were 0.38 × 103 ppm for the ricinine, 0.75 × 103 ppm for a methanol extract ofseeds, 1.97 × 103 ppm for an ethyl acetate seed extract, 2.69×103 ppm for the castor oil, 4.83 × 103 ppm for a methanol extract of leaves, 5.07 × 103 ppm for an ethyl acetate extract of leaves, 9.95 × 103 ppm fora hexane extract of seeds and 10.01 × 103 ppm for a hexane extract of leaves
Darbepoetin Versus Epoetin Alfa for the Correction of Anemia in Cancer Patients Receiving Radiotherapy or Chemoradiotherapy Treatment
Introduction Anemia is the most frequent hematological disturbance in cancer patients, with prevalence between 30% and 90%, depending on the type of tumor, the antitumor treatment, and other factors (infection, malnutrition, bleeding, tumor infiltration of the bone marrow). A number of erythropoietic agents have shown to be effective in increasing the hemoglobin (Hb) levels, reducing the requirements for transfusion, and improving quality of life. The objective of this study is to compare darbepoetin alfa and epoetin alfa when used to correct anemia in cancer patients who are receiving radiotherapy or radiochemotherapy. Material and methods A prospective study of 125 consecutive patients with anemia (Hb < 13 g/dL in males or < 12 g/dL in females) who were undergoing treatment with radiotherapy (RT) or radiochemotherapy (RCT) in our department were enrolled between March 2003 and March 2005. The treatment for the anemia was either darbepoetin alfa 150 mcg/week (62 patients, group 1) or epoetin alfa 40,000 IU/week (63 patients, group 2). Patients received iron supplements in both groups. Treatment was administered in a consecutive manner depending on tumor type. If the increase in Hb was < 1 g/dL after 4 weeks of treatment, the dose was increased to 300 mcg/week in group 1 or to 60,000 IU/week in group 2. The treatment was terminated when a Hb value of ≥ 15 g/dL was reached during RT treatment, a Hb value of ≥ 14 g/dL was reached if the RT had been completed, or after 16 weeks of treatment whatever the Hb value. The mean age of patients was 63.36 ± 11.27 years, 67% were male. No significant differences were observed between the 2 groups in tumor type or stage, previous treatments, or intent to treat with RT or RCT. Results Comparing group 1 and group 2 by intent to treat, the mean Hb at the start of treatment with the study drug was 12.1 g/dL vs 11.8 g/dL, the proportion of patients whose dose was increased was19.7% vs 24.6%, the need for transfusion was 3.2% in each group, the duration of erythropoietic treatment was 6.5 weeks in both groups, and 2 patients in group 2 restarted treatment with epoetin alfa. The percentage of patients who responded (defined as an increase in the Hb ≥ 2 g/dL in the absence of transfusions) was of 72.6% and 66.7%, respectively. Four vascular adverse events were observed, 2 in each group. No significant differences were observed with respect to the baseline, week 4, and week 12 levels of endogenous erythropoietin, serum iron,% saturation, and ferritin. The increase in Hb 1 month after the final administration of the study drug was 2.21 g/dL in group 1 and 2.46 g/dL in group 2 (p = ns). Conclusions The results of our study demonstrate that both treatments are equally effective in correcting anemia in cancer patients undergoing RT or RCT
Bacteriophages of Shiga toxin-producing Escherichia coli and their contribution to pathogenicity
Shiga toxins (Stx) of Shiga toxin-producing Escherichia coli (STEC) are generally encoded in the genome of lambdoid bacteriophages, which spend the most time of their life cycle integrated as prophages in specific sites of the bacterial chromosome. Upon spontaneous induction or induction by chemical or physical stimuli, the stx genes are co-transcribed together with the late phase genes of the prophages. After being assembled in the cytoplasm, and after host cell lysis, mature bacteriophage particles are released into the environment, together with Stx. As members of the group of lambdoid phages, Stx phages share many genetic features with the archetypical temperate phage Lambda, but are heterogeneous in their DNA sequences due to frequent recombination events. In addition to Stx phages, the genome of pathogenic STEC bacteria may contain numerous prophages, which are either cryptic or functional. These prophages may carry foreign genes, some of them related to virulence, besides those necessary for the phage life cycle. Since the production of one or more Stx is considered the major pathogenicity factor of STEC, we aim to highlight the new insights on the contribution of Stx phages and other STEC phages to pathogenicity
Bacteriophages as fecal pollution indicators
Bacteriophages are promising tools for the detection of fecal pollution in different environments, and particularly for viral pathogen risk assessment. Having similar morphological and biological characteristics, bacteriophages mimic the fate and transport of enteric viruses. Enteric bacteriophages, especially phages infecting Escherichia coli (coliphages), have been proposed as alternatives or complements to fecal indicator bacteria. Here, we provide a general overview of the potential use of enteric bacteriophages as fecal and viral indicators in different environments, as well as the available methods for their detection and enumeration, and the regulations for their application
Candida Periprosthetic Joint Infection: Is It Curable?
Fong; Infecció articular periprotèsica; Cirurgia d'intercanvi en dues etapesHongo; Infección de la articulación periprotésica; Cirugía de recambio en dos etapasFungus; Periprosthetic joint infection; Two-stage exchange surgeryCandida periprosthetic joint infection (CPJI) is a rare and very difficult to treat infection, and high-quality evidence regarding the best management is scarce. Candida spp. adhere to medical devices and grow forming biofilms, which contribute to the persistence and relapse of this infection. Typically, CPJI presents as a chronic infection in a patient with multiple previous surgeries and long courses of antibiotic therapy. In a retrospective series of cases, the surgical approach with higher rates of success consists of a two-stage exchange surgery, but the best antifungal treatment and duration of antifungal treatment are still unclear, and the efficacy of using an antifungal agent-loaded cement spacer is still controversial. Until more evidence is available, focusing on prevention and identifying patients at risk of CPJI seems more than reasonable.This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors
Polyaza macroligands as potential agents for heavy metal removal from wastewater
Two polyaza macroligands N,N´-bis(2-aminobenzyl)-1,2- ethanediamine (L1) and 3,6,9,12-tetraaza-4(1,2),11(1,2)-dibenzo-1(1,3)- piridinaciclotridecafano (L2) were characterized and investigated for their metal ion extraction capabilities. The nature of all complexes was established by spectroscopic techniques. The equilibrium constants were determined by spectrophotometric and potentiometric techniques and the residual concentration of metals in the solutions by Atomic Absorption Spectrometry (AAS). The capacity of the ligands to remove heavy metals such as Cu(II), Ni(II), Cd(II), Zn(II) and Pb(II) as insoluble complexes was evaluated in wastewater from industrial effluents. These agents showed high affinity for the studied metals. The values of equilibrium constants of the isolated complexes (between 1 x 104 and 2 x 107) demonstrated the feasibility of applying these chelating agents as an alternative to remove heavy metals from industrial effluents
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