424 research outputs found

    Using principles of authentic assessment to redesign written examinations and tests

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    Tests and examinations are widely used internationally. Despite their pervasiveness, they tend to measure lower order thinking skills in a decontextualized manner at a time when the literature frequently argues for the benefits of a richer, authentic approach to assessment. The focus of this paper is to improve authenticity in test assessment methods through promoting realism, cognitive challenge and evaluative judgement during the planning, administering and following up of assessment tasks. The article builds on a systematic literature review, in which the main principles of authentic assessment were outlined. In this paper, we posit how these principles can be implemented through the three chronological phases of the assessment process: before, during and after the act of assessment

    (−)-Istanbulin A

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    The title compound (systematic name: 9a-hydr­oxy-3,4a,5-trimethyl-4a,6,7,8a,9,9a-hexa­hydro-4H,5H-naphtho[2,3-b]furan-2,8-dione), C15H20O4, is a sesquiterpene lactone showing the typical eremophilanolide skeleton, which has been isolated from the plant Senecio candidans collected in the Chilean Magallanes region. The present study confirms the atomic connectivity assigned on the basis of 1H and 13C NMR spectroscopy, as well as the relative stereochemistry of the 4α-methyl,5α-methyl,8β-hydr­oxy,10β-H unit. The crystal structure is stabilized by inter­molecular O—H⋯O hydrogen bonds involving the hydr­oxy group as donor and the oxo group as acceptor, giving chains along the a axis. The absolute structure was not determined because of the lack of suitable anomalous scatters

    Ingesta de macronutrientes y prevalencia de malnutrición por exceso en escolares de 5o y 6o básico de distinto nivel socioeconómico de la región metropolitana

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    Obesity in childhood has become an important publie health problem in Chile. Objetive: to study macronutrient intake and nutritional status in school-age children attending5th andóth grade inprimary schoolsfrom different socioeconomic status located in 6 counties in Santiago, Chile. Methods: A total of 1,732 children between 9 and 12 years oldjrom both sexes were studied. Anthropometric evaluation included weight, height, and tricipital and subescapular thickness. Macronutrient intake was determined using a 24-hours recall survey. Socioeconomic status was estimated using the ESOMAR survey. Results: In this sample overweight and obesity prevalence reached 40%. Prevalence was higher in boys and in the lower socio-economic groups. A higher consumption ofproteins andfat wasfound in the wealthier groups, while a higher intake of carbohydrates was present in the poorer ones. Comparison with the daily recommended allowancesfound that both males andfemales hada 75% ofadequacy of all ofmacronutrients with the exception offiber. Conclusión: The study revealeda highprevalence ofmalnutrition in both sexes with a better nutrition standard among children in higher socioeconomic status.El sobrepeso y la obesidad infantil se han transformado en un importante problema en salud pública. Objetivo: evaluar la ingesta de macronutrientes y determinar la prevalencia de malnutrición en escolares de 5° y 6o año básico de distintos niveles socioeconómicos de 6 comunas de la Región Metropolitana. Sujetos y método: se evaluaron 1732 niños de ambos sexos de 9 a 12 años de edad. La evaluación antropométrica incluyo peso, talla, pliegue tricipital y subescapular. La ingesta de macronutrientes se evaluó mediante la aplicación de una encuesta recordatorio de 24 hrs; el nivel socioeconómico se evaluó mediante la aplicación la encuesta ESOMAR. Resultados: la prevalencia de malnutrición por exceso fue de 40%, siendo más importante en hombres de los estratos socioeconómicos de menores ingresos. Encontramos un mayor consumo de proteínas y grasas totales en el nivel socioeconómico más alto, mientras que el nivel de menores ingresos tuvo una mayor ingesta de carbohidratos. Tanto hombres como mujeres presentaron una adecuación superior al 75% en todos los macronutrientes con excepción de la fibra. Conclusión: El estudio arrojó una elevada prevalencia de malnutrición por exceso en ambos sexos con un mejor patrón de alimentación en los niños de nivel socioeconómico alto

    Building extended resolvent of heat operator via twisting transformations

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    Twisting transformations for the heat operator are introduced. They are used, at the same time, to superimpose a` la Darboux N solitons to a generic smooth, decaying at infinity, potential and to generate the corresponding Jost solutions. These twisting operators are also used to study the existence of the related extended resolvent. Existence and uniqueness of the extended resolvent in the case of NN solitons with N "ingoing" rays and one "outgoing" ray is studied in details.Comment: 15 pages, 2 figure

    Magnetic characterization of Fe, Ni, Co nanoparticles dispersed in phyllosilicate type silicon oxide

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    International audienceWe present the magnetic properties of silica-supported metal (Fe,catalyst) nanoparticles synthesized by precipitation of metal nitrate in ammonia-based medium. Our goal is the study of possible metal-support interactions in the nanoporous catalyst. The temperature dependence of the magnetization for all samples display spin-glass like behavior below c.a. 11-12 K, with clear Curie-Weiss dependence in the high-temperature regime. Spin-glass-like behavior was inferred from dynamic AC susceptibility data after analyzing the frequency-dependence of the in-phase component χ'(f) by the expression W = ΔTf/[Tf Δlog(f)] = 3.0 × 10−3. We found that the magnetic behavior of the catalyst is drastically affected by the existence of interactions between the metal and the support

    On the equivalence of different approaches for generating multisoliton solutions of the KPII equation

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    The unexpectedly rich structure of the multisoliton solutions of the KPII equation has been explored by using different approaches, running from dressing method to twisting transformations and to the tau-function formulation. All these approaches proved to be useful in order to display different properties of these solutions and their related Jost solutions. The aim of this paper is to establish the explicit formulae relating all these approaches. In addition some hidden invariance properties of these multisoliton solutions are discussed

    Mitochondrial dysfunction in peripheral blood mononuclear cells in pediatric septic shock

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    OBJECTIVES: Mitochondrial dysfunction in peripheral blood mononuclear cells has been linked to immune dysregulation and organ failure in adult sepsis, but pediatric data are limited. We hypothesized that pediatric septic shock patients exhibit mitochondrial dysfunction within peripheral blood mononuclear cells which in turn correlates with global organ injury. DESIGN: Prospective observational study. SETTING: Academic PICU. PATIENTS: Thirteen pediatric patients with septic shock and greater than or equal to two organ failures and 11 PICU controls without sepsis or organ failure. INTERVENTIONS: Ex vivo measurements of mitochondrial oxygen consumption and membrane potential (DeltaPsim) were performed in intact peripheral blood mononuclear cells on day 1-2 and day 5-7 of septic illness and in controls. The Pediatric Logistic Organ Dysfunction score, inotrope score, and organ failure-free days were determined from medical records. MEASUREMENTS AND MAIN RESULTS: Spare respiratory capacity, an index of bioenergetic reserve, was lower in septic peripheral blood mononuclear cells on day 1-2 (median, 1.81; interquartile range, 0.52-2.09 pmol O2/s/10 cells) compared with controls (5.55; 2.80-7.21; p = 0.03). Spare respiratory capacity normalized by day 5-7. Patients with sepsis on day 1-2 exhibited a higher ratio of LEAK to maximal respiration than controls (17% vs \u3c 1%; p = 0.047) with normalization by day 5-7 (1%; p = 0.008), suggesting mitochondrial uncoupling early in sepsis. However, septic peripheral blood mononuclear cells exhibited no differences in basal or adenosine triphosphate-linked oxygen consumption or DeltaPsim. Oxygen consumption did not correlate with Pediatric Logistic Organ Dysfunction score, inotrope score, or organ failure-free days (all p \u3e 0.05). Although there was a weak overall association between DeltaPsim on day 1-2 and organ failure-free days (Spearman rho = 0.56, p = 0.06), patients with sepsis with normal organ function by day 7 exhibited higher DeltaPsim on day 1-2 compared with patients with organ failure for more than 7 days (p = 0.04). CONCLUSIONS: Mitochondrial dysfunction was present in peripheral blood mononuclear cells in pediatric sepsis, evidenced by decreased bioenergetic reserve and increased uncoupling. Mitochondrial membrane potential, but not respiration, was associated with duration of organ injury

    Dispersionless limit of the noncommutative potential KP hierarchy and solutions of the pseudodual chiral model in 2+1 dimensions

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    The usual dispersionless limit of the KP hierarchy does not work in the case where the dependent variable has values in a noncommutative (e.g. matrix) algebra. Passing over to the potential KP hierarchy, there is a corresponding scaling limit in the noncommutative case, which turns out to be the hierarchy of a `pseudodual chiral model' in 2+1 dimensions (`pseudodual' to a hierarchy extending Ward's (modified) integrable chiral model). Applying the scaling procedure to a method generating exact solutions of a matrix (potential) KP hierarchy from solutions of a matrix linear heat hierarchy, leads to a corresponding method that generates exact solutions of the matrix dispersionless potential KP hierarchy, i.e. the pseudodual chiral model hierarchy. We use this result to construct classes of exact solutions of the su(m) pseudodual chiral model in 2+1 dimensions, including various multiple lump configurations.Comment: 37 pages, 10 figures, 2nd version: some extensions (Fig 3, Appendix A, additional references), 3rd version: some minor changes, additional reference
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