Using principles of authentic assessment to redesign written examinations and tests

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

Distinguishing noise from chaos: objective versus subjective criteria using Horizontal Visibility Graph

A recently proposed methodology called the Horizontal Visibility Graph (HVG) [Luque {\it et al.}, Phys. Rev. E., 80, 046103 (2009)] that constitutes a geometrical simplification of the well known Visibility Graph algorithm [Lacasa {\it et al.\/}, Proc. Natl. Sci. U.S.A. 105, 4972 (2008)], has been used to study the distinction between deterministic and stochastic components in time series [L. Lacasa and R. Toral, Phys. Rev. E., 82, 036120 (2010)]. Specifically, the authors propose that the node degree distribution of these processes follows an exponential functional of the form $P(\kappa)\sim \exp(-\lambda~\kappa)$, in which $\kappa$ is the node degree and $\lambda$ is a positive parameter able to distinguish between deterministic (chaotic) and stochastic (uncorrelated and correlated) dynamics. In this work, we investigate the characteristics of the node degree distributions constructed by using HVG, for time series corresponding to $28$ chaotic maps and $3$ different stochastic processes. We thoroughly study the methodology proposed by Lacasa and Toral finding several cases for which their hypothesis is not valid. We propose a methodology that uses the HVG together with Information Theory quantifiers. An extensive and careful analysis of the node degree distributions obtained by applying HVG allow us to conclude that the Fisher-Shannon information plane is a remarkable tool able to graphically represent the different nature, deterministic or stochastic, of the systems under study.Comment: Submitted to PLOS On

New version of the Pediatric Evaluation of Disability Inventory (PEDI-CAT): translation, cultural adaptation to Brazil and analyses of psychometric properties

BACKGROUND: The Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT), developed with innovative measurement methodologies, evaluates functioning of children and youth, from 0 to 21 years, with different health conditions. It is a revision of an earlier instrument (PEDI) that has been used in national and international clinical practice and research. It was felt to be necessary to make this new version (PEDI-CAT) available in Brazil. OBJECTIVES: Translate and culturally adapt the PEDI-CAT to the Brazilian-Portuguese language and test its psychometric properties. METHOD: This methodological study was developed through the following stages: (1) translation, (2) synthesis, (3) back-translation, (4) revision by an expert committee, (5) testing of the pre-final version, and (6) evaluation of the psychometric properties. The 276 translated PEDI-CAT items were divided into three age groups (0-7, 8-14, and 15-21 years). RESULTS: The PEDI-CAT translation followed all six stages. The adaptations incorporated cultural and socioeconomic class specificities. The PEDI-CAT/Brazil showed good indices of inter-examiner (intraclass correlation coefficient-ICC=0.83-0.89) and test-retest (ICC=0.96-0.97) reliability, good internal consistency (0.99) and small standard error of measurement in all three age groups (0.12-0.17). Factor analyses grouped the items from the three functional skills domains into one factor, and items from the responsibility scale into three factors, supporting the adequacy of these factor solutions to the conceptual structure of the instrument and the developmental model. CONCLUSION: The PEDI-CAT/Brazil is a theoretically consistent, culturally appropriate, and reliable instrument. Its availability in Brazil will contribute to the evaluation and measurement of functional outcomes from clinical interventions, longitudinal follow-up, and rehabilitation research

Treatment of chromium(VI) solutions in a pilot-scale bioreactor through a biofilm of arthrobacter viscosus supported on GAC

The aim of this work is to evaluate the applicability of a biofilm to the removal of chromium in solution, at a pilot scale. The effect of the initial concentration of metal on the biosorption behavior of an Arthrobacter viscosus biofilm supported on granular activated carbon, in batch and column essays was also analyzed. Six isotherm equations have been tested in the present study. The best fit was obtained with the Freundlich model. It was observed that as the initial chromium concentration increases, the uptake increases too, but the removal percentage decreases, with values between 95.20% (C0 = 5 mg/l) and 38.28% (C0 = 1000 mg/l). The batch adsorption studies were used to develop a pilot bioreactor able to remove chromium from aqueous solutions. Data obtained in a pilot-scale reactor showed an average removal percentage of 99.9%, during the first 30 days, for the initial concentration of 10 mg/l and an average removal percentage of 72%, for the same period and for the initial concentration of 100 mg/l. Uptake values of 11.35 mg/g and 14.55 mg/g were obtained, respectively, for the initial concentration of 10 and 100 mg/l. The results obtained are very promising and encourage the utilization of this biofilm in environmental applications.FEDERFundação para a Ciência e a Tecnologia (FCT

Treatment of chromium solutions in a 15 dm3 pilot bioreactor

Chromium is a heavy metal with large industrial applications such as in textile dying, chemicals and pigments production, wood preservation, tanning activity and electroplating for surface treatment. The treatment of wastewater containing this metal with biological methods is strongly recommended, especially when in the form of Cr (VI) due its high toxicity. The biosorption system consists of a bacterial biofilm supported on granular activated carbon (GAC), placed in contact with the polluted solutions. The bacterium used for the formation of the biofilm was Arthrobacter viscosus. Two concentrations of chromium were used: 10 mg/l and 100 mg/l, with a flow rate of 25 mg/l. The data obtained in a pilot-scale reactor showed an average removal percentage of 99.9%, during the first 30 days, for the initial concentration of 10 mg/l and average removal percentage of 72%, for the same period and for the initial concentration of 100 mg/l. Uptake values of 11.35 mg/gGAC and 14.55 mg/gGAC were obtained, respectively, for the initial concentration of 10 and 100 mg/l. The presence of functional groups on the cell wall surface of the biomass that may interact with the metal ion was confirmed by FTIR. The results obtained are very promising and encourage the utilization of this biofilm in environmental applications

A sustained approach to environmental catalysis: Reutilization of chromium from wastewater

Wastewater pollution with heavy metals is an issue of great environmental concern. The future development of clean technologies for the treatment of wastewater loaded with heavy metals entails environment friendly and sustainable processes that may allow simultaneously the recovery of the metals and their reutilization as value-added catalysts to be used in environmental applications. This is the first review regarding the biorecovery of metals and their further reutilization as heterogeneous catalysts. In this regard, metallic residues that generally would be considered as a waste at the end of the treatment process can be reutilized and transformed into value-added catalysts to be used in environmental applications. This review is focused in two broad areas: the biorecovery of chromium by a combined biosorption system consisting of bacteria supported on zeolites, and the catalytic reutilization of the metal-loaded zeolites in the oxidation of organic compounds, both in gaseous and liquid phase. After an overview describing the main subjects in the field of heavy metals recovery, biosorption, zeolites and catalytic oxidation, in the following sections special emphasis will be given to the main results and findings regarding these clean technologies of biorecovery and reuse of metals in catalytic reactions of environmental concern.B. Silva is thankful for the Project “BioEnv—Biotechnology and Bioengineering for a sustainable world,” REF. NORTE-07-0124-FEDER-000048, cofunded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER. The authors are grateful to FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the Research Centres, PEst-OE/EQB/LA0023/2013, and PEst-C/QUI/UI0686/2013 (F-COMP-01-0124-FEDER-037302)

Carrier mobility and scattering lifetime in electric double-layer gated few-layer graphene

We fabricate electric double-layer field-effect transistor (EDL-FET) devices on mechanically exfoliated few-layer graphene. We exploit the large capacitance of a polymeric electrolyte to study the transport properties of three, four and five-layer samples under a large induced surface charge density both above and below the glass transition temperature of the polymer. We find that the carrier mobility shows a strong asymmetry between the hole and electron doping regime. We then employ ab-initio density functional theory (DFT) calculations to determine the average scattering lifetime from the experimental data. We explain its peculiar dependence on the carrier density in terms of the specific properties of the electrolyte we used in our experiments.Comment: 6 pages, 3 figure

Silk reinforced with graphene or carbon nanotubes spun by spiders

Here, we report the production of silk incorporating graphene and carbon nanotubes directly by spider spinning, after spraying spiders with the corresponding aqueous dispersions. We observe a significant increment of the mechanical properties with respect to the pristine silk, in terms of fracture strength, Young's and toughness moduli. We measure a fracture strength up to 5.4 GPa, a Young's modulus up to 47.8 GPa and a toughness modulus up to 2.1 GPa, or 1567 J/g, which, to the best of our knowledge, is the highest reported to date, even when compared to the current toughest knotted fibres. This approach could be extended to other animals and plants and could lead to a new class of bionic materials for ultimate applications