815 research outputs found

    Constructive habituation as an educational approach to process-object reification in mathematics

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    Sfard and Thompson (1994) state that what matters most is that educators develop ways of thinking, teaching, and learning mathematics. This study introduced constructive habituation, a new strategy developed to aid both students and teachers in the thinking, teaching, and learning of mathematics. Constructive habituation attempts to unite constructivist teaching methods aimed at supporting students’ conceptual understanding of content and habituationist teaching method aimed at establishing routine responses to routine tasks. This study is exploratory in nature, designed to investigate if constructive habituation is a more effective means than a traditional teaching method in helping students reach process-object reification as evidenced by higher levels of student achievement. The study primarily addressed introductory function concepts and symmetry and transformations of functions. The subjects were university students enrolled in a precalculus I course. The results indicated that constructive habituation was not a more effective means in helping students reach process-object reification than a traditional teaching method. No significant differences were found for any of the variables examined. However, some promising practical results were revealed. The students taught using the experimental method averaged more than nine points higher than the students taught using a more traditional teaching method on an examination that evaluated their understandings of the relationship between changes made to the graph of a function and changes made to its formula. Explanations on why constructive habituation may not have reached its intended goal are given. A discussion is presented of the developmental stage at which constructive habituation may become an effective pedagogical method. Study also includes a brief history of the major pedagogical movements over the last half century and the psychological perspectives that influenced each

    TCL Mobile LTDA

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    El alcance sobre este PAP es iniciar y dar soporte a la empresa TCL como becario, en el cual se nos enseña cómo trabajan los demás miembros e ingenieros del equipo de validación que es en el área donde estaré trabajando como becario. En el área de validación por parte de la empresa TCL, se encarga de verificar y validar los diferentes proyectos de smart phones que desarrolla la empresa. En este documento hablaré sobre mi desarrollo en la empresa y este PAP. En el cual explicare sobre los conocimientos adquiridos y las actividades que realice como becario. También hablaré un poco sobre la empresa y a que se dedica, solo daré breves datos por motivos de confidencialidad que no puedo compartir sobre todas mis actividades o compañeros de trabajo. Hay puntos durante este documento que me permitieron tener una mejor vición y darle un enfoque diferente a mi trabajo como becario, de igual manera tomo varios puntos que me permiten revisar los conocimientos adquiridos, actividades desarrolladas, eficiencia en mi trabajo y las posibilidades que puedo obtener al realizar mi PAP en una empresa.ITESO, A.C

    Conjugated linoleic acid content in milk of Chilean Black Friesian cows under pasture conditions and supplemented with canola seed (Brassica napus) concentrate

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    At present, there is limited and contradictory information about the effects of the use of canola (Brassica napus) seed as supplement on the contents of conjugated linoleic acid (CLA) in milk of grazing cows. The objective of this study was to evaluate the effect of a dietary supplement with canola seed on the production and composition of milk, and CLA concentration in Chilean Black Friesian cows under pasture conditions. Three experiments were done. Experiment 1: control group was fed 5 kg d–1 of commercial concentrate without canola (0-TC1) and treatment group that was fed 3.75 kg of commercial concentrate plus 1.16 kg of whole canola seed (1.16-TC1). Experiment 2: Control group was fed 8 kg d–1 commercial concentrate without canola (0-TC2) and treatment group that was fed 6.2 kg of commercial concentrate plus 1.2 kg of ground canola seed (1.2-TC2). Experiment 3: control group was fed 6 kg d–1 commercial concentrate without canola (0-TC3) and treatment group was fed 6 kg of commercial concentrate with 20% of whole canola seed (1.2 kg d–1, 1.2-TC3). The duration of each experiment was 60 days. No differences in milk production and quality were observed among the experimental groups in every assay. The CLA isomers trans-10, cis-12 and cis-10, cis-12 were higher than those normally found in the scientific literature. There was no effect of the inclusion of canola seed on total CLA content or the content of cis-9, trans-11, trans-10, cis-12 and cis-10, cis-12 isomers

    Further evidence of Chelonid herpesvirus 5 (ChHV5) latency : High levels of ChHV5 DNA detected in clinically healthy marine turtles

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    The Chelonid herpesvirus 5 (ChHV5) has been consistently associated with fibropapillomatosis (FP), a transmissible neoplastic disease of marine turtles. Whether ChHV5 plays a causal role remains debated, partly because while FP tumours have been clearly documented to contain high concentrations of ChHV5 DNA, recent PCRbased studies have demonstrated that large proportions of asymptomatic marine turtles are also carriers of ChHV5. We used a real-time PCR assay to quantify the levels of ChHV5 Glycoprotein B (gB) DNA in both tumour and non-tumour skin tissues, from clinically affected and healthy turtles drawn from distant ocean basins across four species. In agreement with previous studies, higher ratios of viral to host DNA were consistently observed in tumour versus non-tumour tissues in turtles with FP. Unexpectedly however, the levels of ChHV5 gB DNA in clinically healthy turtles were significantly higher than in non-tumour tissues from FP positive turtles. Thus, a large proportion of clinically healthy sea turtle populations worldwide across species carry ChHV5 gB DNA presumably through persistent latent infections. ChHV5 appears to be ubiquitous regardless of the animals' clinical conditions. Hence, these results support the theory that ChHV5 is a near ubiquitous virus with latency characteristics requiring co-factors, possibly environmental or immune related, to induce FP

    QuickSNP: an automated web server for selection of tagSNPs

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    Although large-scale genetic association studies involving hundreds to thousands of SNPs have become feasible, the associated cost is substantial. Even with the increased efficiency introduced by the use of tagSNPs, researchers are often seeking ways to maximize resource utilization given a set of SNP-based gene-mapping goals. We have developed a web server named QuickSNP in order to provide cost-effective selection of SNPs, and to fill in some of the gaps in existing SNP selection tools. One useful feature of QuickSNP is the option to select only gene-centric SNPs from a chromosomal region in an automated fashion. Other useful features include automated selection of coding non-synonymous SNPs, SNP filtering based on inter-SNP distances and information regarding the availability of genotyping assays for SNPs and whether they are present on whole genome chips. The program produces user-friendly summary tables and results, and a link to a UCSC Genome Browser track illustrating the position of the selected tagSNPs in relation to genes and other genomic features. We hope the unique combination of features of this server will be useful for researchers aiming to select markers for their genotyping studies. The server is freely available and can be accessed at the URL http://bioinformoodics.jhmi.edu/quickSNP.pl

    Isolation and Identification of an Antimutagenic Phthalate Derivative Compound from Octopus (Paraoctopus limaculatus)

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    Purpose: To isolate and evaluate the antimutagenic properties of compounds previously identified in octopus (Paraoctopus limaculatus).Methods: Octopus fractions, previously obtained by a sequential thin layer chromatography (TLC) procedure, were subjected to further fractionation by TLC and their anti-mutagenic activity monitored using Salmonella tester strains TA98 and TA100 with metabolic activation (S9) in Ames test. The isolated fractions were subjected to structural studies by Fourier transformed infrared spectroscopy (FTIR), nuclear magnetic resonance (1H and 13C NMR), and gas chromatography-mass spectrometry.Results: Five new fractions were obtained from a previously isolated and reported anti-mutagenic octopus fraction. Fractions RB21321b2 and RB21321b3 inhibited > 80 % of the mutagenicity induced by 500 ng AFB1 on both tester strains and were selected for chemical/structural characterization. Data from IR and 1H and 13C NMR suggested the presence of phthalate type of compounds. GC-MS analysis revealed 278 m/z for both fractions which is consistent with a butyl isobutyl phthalate structure.Conclusion: Based on the findings, the compound responsible for the high anti-mutagenic activity of the isolated fraction from octopus is 1-butyl-2-isobutyl-phthalate.Keywords: Octopus, Anti-Mutagenic, Paraoctopus limaculatus, 1-Butyl-2-isobutyl-phthalat

    Joining the conspiracy? Negotiating ethics and emotions in researching (around) AIDS in southern Africa

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    AIDS is an emotive subject, particularly in southern Africa. Among those who have been directly affected by the disease, or who perceive themselves to be personally at risk, talking about AIDS inevitably arouses strong emotions - amongst them fear, distress, loss and anger. Conventionally, human geography research has avoided engagement with such emotions. Although the ideal of the detached observer has been roundly critiqued, the emphasis in methodological literature on 'doing no harm' has led even qualitative researchers to avoid difficult emotional encounters. Nonetheless, research is inevitably shaped by emotions, not least those of the researchers themselves. In this paper, we examine the role of emotions in the research process through our experiences of researching the lives of 'Young AIDS migrants' in Malawi and Lesotho. We explore how the context of the research gave rise to the production of particular emotions, and how, in response, we shaped the research, presenting a research agenda focused more on migration than AIDS. This example reveals a tension between universalised ethics expressed through ethical research guidelines that demand informed consent, and ethics of care, sensitive to emotional context. It also demonstrates how dualistic distinctions between reason and emotion, justice and care, global and local are unhelpful in interpreting the ethics of research practice

    Comparison of Upper Tropospheric Carbon Monoxide from MOPITT, ACE-FTS, and HIPPO-QCLS

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    Products from the Measurements Of Pollution In The Troposphere (MOPITT) instrument are regularly validated using in situ airborne measurements. However, few of these measurements reach into the upper troposphere, thus hindering MOPITT validation in that region. Here we evaluate upper tropospheric (~500 hPa to the tropopause) MOPITT CO profiles by comparing them to satellite Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) retrievals and to measurements from the High-performance Instrumented Airborne Platform for Environmental Research Pole to Pole Observations (HIPPO) Quantum Cascade Laser Spectrometer (QCLS). Direct comparison of colocated v5 MOPITT thermal infrared-only retrievals, v3.0 ACE-FTS retrievals, and HIPPO-QCLS measurements shows a slight positive MOPITT CO bias within its 10% accuracy requirement with respect to the other two data sets. Direct comparison of colocated ACE-FTS and HIPPO-QCLS measurements results in a small number of samples due to the large disparity in sampling pattern and density of these data sets. Thus, two additional indirect techniques for comparison of noncoincident data sets have been applied: tracer-tracer (CO-O3) correlation analysis and analysis of profiles in tropopause coordinates. These techniques suggest a negative bias of ACE-FTS with respect to HIPPO-QCLS; this could be caused by differences in resolution (horizontal, vertical) or by deficiencies in the ACE-FTS CO retrievals below ~20 km of altitude, among others. We also investigate the temporal stability of MOPITT and ACE-FTS data, which provide unique global CO records and are thus important in climate analysis. Our results indicate that the relative bias between the two data sets has remained generally stable during the 2004–2010 period. © 2014. American Geophysical Union
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