1,596 research outputs found

    Common Visual Representations as a Source for Misconceptions of Preservice Teachers in a Geometry Connection Course

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    In this paper, we demonstrate how atypical visual representations of a triangle, square or a parallelogram may hinder students’ understanding of a median and altitude. We analyze responses and reasoning given by 16 preservice middle school teachers in a Geometry Connection class. Particularly, the data were garnered from three specific questions posed on a cumulative final exam, which focused on computing and comparing areas of parallelograms, and triangles represented by atypical images. We use the notions of concept image and concept definition as our theoretical framework for an analysis of the students’ responses. Our findings have implication on how typical images can impact students’ cognitive process and their concept image. We provide a number of suggestions that can foster conceptualization of the notions of median and altitude in a triangle that can be realized in an enacted lesson

    Systematic review of psychological approaches to the management of neuropsychiatric symptoms of dementia

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    Objective: The authors systematically reviewed the literature on psychological approaches to treating the neuropsychiatric symptoms of dementia.Method: Reports of studies that examined effects of any therapy derived from a psychological approach that satisfied prespecified criteria were reviewed. Data were extracted, the quality of each study was rated, and an overall rating was given to each study by using the Oxford Centre for Evidence-Based Medicine criteria.Results: A total of 1,632 studies were identified, and 162 satisfied the inclusion criteria for the review. Specific types of psychoeducation for caregivers about managing neuropsychiatric symptoms were effective treatments whose benefits lasted for months, but other caregiver interventions were not. Behavioral management techniques that are centered on individual patients' behavior or on caregiver behavior had similar benefits, as did cognitive stimulation. Music therapy and Snoezelen, and possibly sensory stimulation, were useful during the treatment session but had no longer-term effects; interventions that changed the visual environment looked promising, but more research is needed.Conclusions: Only behavior management therapies, specific types of caregiver and residential care staff education, and possibly cognitive stimulation appear to have lasting effectiveness for the management of dementia-associated neuropsychiatric symptoms. Lack of evidence regarding other therapies is not evidence of lack of efficacy. Conclusions are limited because of the paucity of high-quality research ( only nine level-1 studies were identified). More high-quality investigation is needed

    Mapping topography and broad vegetation type to characterise the Boxford meadows SSSI (Unit 2)

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    Understanding the dynamic relationship between hydrology and ecology in a complex wetland setting should be considered integral to the sustainable management and conservation of wetland habitats and future water resource planning. Wetland hydrology can exhibit considerable spatial complexity as a result of sub surface and surface heterogeneity. The latter of which may be determined by the relationship between spatial topography variation and broad vegetation distribution. Any study to investigate such a relationship must be at a spatial resolution sufficient to identify patterns in surface topography and vegetation type. In this study state of the art survey technology was used to collect and record for subsequent mapping the topographic and vegetation characteristics of the Boxford lowland chalk groundwater dependent terrestrial ecosystem (GDTE). The resultant survey dataset successfully unveiled distinct patterns in topography and vegetation type. The analysis of the data in a Geographical Information System (GIS) desk confirmed for the first time the presence of paleo-channels and a braided fluvial system within the meadows. In addition the combined survey method gives some indication that the type of vegetation present appears to coincide with some of the more distinctive topographical features. The results demonstrate that combining the field survey campaign alongside desk based GIS analysis is an extremely useful and versatile tool and can provide valuable information to support the decision making process for both further scientific investigation and sustainable habitat management

    SOME BIOCHEMICAL PROPERTIES OF THYMUS LEUKEMIA ANTIGENS SOLUBILIZED FROM CELL MEMBRANES BY PAPAIN DIGESTION

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    Thymus leukemia (TL) alloantigenic activity was solubilized by papain proteolytic digestion from intact RADA1 tumor cells. If the cells were labeled with amino acids and fucose, the TL alloantigen could be isolated as a doubly labeled glycoprotein fragment by indirect precipitation from the papain digest. This TL glycoprotein fragment was approximately the same mol wt as the papain-digested H-2.4 alloantigen fragment as judged by chromatography on Sephadex G-150 in sodium dodecyl sulfate. The carbohydrate chain of the TL glycoprotein obtained by exhaustive pronase digestion behaved as a glycopeptide of approximately 4,500 mol wt, as compared with the glycopeptide of the H-2.4 alloantigen that had a mol wt of about 3,500. Thus, the TL alloantigen can be solubilized by papain digestion as a glycoprotein fragment similar in mol wt to the H-2 alloantigen glycoprotein fragment. The carbohydrate chain of the TL glycoprotein is larger than the H-2 carbohydrate chain

    Projecting impacts of climate change on habitat availability in a macrophyte dominated chalk river

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    Climate change will impact fluvial ecosystems through changes in the flow regime. Physical habitat is an established measure of a river's ecological status when assessing changes to flow. Yet, it requires extensive datasets, is site specific, and does not account for dynamic processes; shortcomings that the use of hydrological and hydraulic models may alleviate. Here, simulated flows along a 600 m reach of the River Lambourn, Boxford, UK, were extracted from the 1D MIKE 11 hydraulic component of an integrated MIKE SHE model of the Centre for Ecology & Hydrology River Lambourn Observatory. In-channel seasonal macrophyte growth and management through cutting alter water levels, represented in the hydraulic model by manipulating channel bed roughness (Manning's n). Assessment of climate change used outputs from the UK Climate Projections 2009 ensemble of global climate models for the 2080s. River discharge outputs were disaggregated to provide velocity and depth profiles across 41 cross sections along the reach. These were integrated with habitat suitability criteria for brown trout (Salmo trutta) to generate a measure of available physical habitat. The influence of macrophyte growth caused the habitat-discharge relationship to be unusable in evaluating the sensitivity of brown trout to flow changes. Instead, projected time series were used to show an overall reduction in habitat availability, more for adult than juvenile trout. Results highlighted the impact of weed cutting, and its potential role in mitigating both flood risk and the ecological impacts of climate change. The use of a hydraulic model to assess physical habitat availability has worldwide applicability

    Exploring the progenitors of brightest cluster galaxies at z ∼ 2

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    We present a new method for tracing the evolution of brightest cluster galaxies (BCGs) from z ∼ 2 to z ∼ 0. We conclude on the basis of semi-analytical models that the best method to select BCG progenitors at z ∼ 2 is a hybrid environmental density and stellar mass ranking approach. Ultimately, we are able to retrieve 45 per cent of BCG progenitors. We apply this method on the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, Ultra Deep Survey data to construct a progenitor sample at high redshift. We furthermore populate the comparisons in local Universe by using Sloan Digital Sky Survey data with statistically likely contamination to ensure a fair comparison between high and low redshifts. Using these samples we demonstrate that the BCG sizes have grown by a factor of ∼3.2 since z ∼ 2, and BCG progenitors are mainly late-type galaxies, exhibiting less concentrated profiles than their early type local counterparts. We find that BCG progenitors have more disturbed morphologies. In contrast, local BCGs have much smoother profiles. Moreover, we find that the stellar masses of BCGs have grown by a factor of ∼2.5 since z ∼ 2, and the star formation rate of BCG progenitors has a median value of 13.5 Mʘ yr‾¹, much higher than their quiescent local descendants. We demonstrate that over z = 1–2 star formation and merging contribute equally to BCG mass growth. However, merging plays a dominant role in BCG assembly at z ≲ 1. We also find that BCG progenitors at high z are not significantly different from other galaxies of similar mass at the same epoch. This suggests that the processes which differentiate BCGs from normal massive elliptical galaxies must occur at z ≲ 2

    A linear plasmid truncation induces unidirectional flagellar phase change in H:z66 positive Salmonella Typhi

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    The process by which bacteria regulate flagellar expression is known as phase variation and in Salmonella enterica this process permits the expression of one of two flagellin genes, fliC or fljB, at any one time. Salmonella Typhi (S. Typhi) is normally not capable of phase variation of flagellar antigen expression as isolates only harbour the fliC gene (H:d) and lacks an equivalent fljB locus. However, some S. Typhi isolates, exclusively from Indonesia, harbour an fljB equivalent encoded on linear plasmid, pBSSB1 that drives the expression of a novel flagellin named H:z66. H:z66+S. Typhi isolates were stimulated to change flagellar phase and genetically analysed for the mechanism of variation. The phase change was demonstrated to be unidirectional, reverting to expression from the resident chromosomal fliC gene. DNA sequencing demonstrated that pBSSB1 linear DNA was still detectable but that these derivatives had undergone deletion and were lacking fljAz66 (encoding a flagellar repressor) and fljBz66. The deletion end-point was found to involve one of the plasmid termini and a palindromic repeat sequence within fljBz66, distinct to that found at the terminus of pBSSB1. These data demonstrate that, like some Streptomyces linear elements, at least one of the terminal inverted repeats of pBSSB1 is non-essential, but that a palindromic repeat sequence may be necessary for replication

    Tidal Energy Round Robin Tests: A Comparison of Flow Measurements and Turbine Loading

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    A Round Robin Tests program is being undertaken within the EC MaRINET2 initiative. This programme studies the used facility influence can have on the performance evaluation of a horizontal axis tidal turbine prototype when it is operated under wave and current conditions. In this paper, we present the design of experiments that is used throughout the work programme and the results related to the flow characterisation obtained at the Ifremer wave and current circulating tank, the Cnr-Inm wave towing tank and the ocean research facility FloWave. These facilities have been identified to provide adequate geometric conditions to accommodate a 0.724 m diameter turbine operating at flow velocities of 0.8 and 1.0 m/s. The set-up is replicated in each of the facilities with exemption of the amount of flow measuring instruments. Intrinsic differences in creating wave and currents between facilities are found. Flow velocities are up to 10% higher than the nominal values and wave amplitudes higher than the target values by up to a factor of 2. These discrepancies are related to the flow and wave generation methods used at each facility. When the flow velocity is measured besides the rotor, the velocity presents an increase of 8% compared to the upstream measurements

    Results of a randomized, double-blind phase II clinical trial of NY-ESO-1 vaccine with ISCOMATRIX adjuvant versus ISCOMATRIX alone in participants with high-risk resected melanoma.

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    BACKGROUND: To compare the clinical efficacy of New York Esophageal squamous cell carcinoma-1 (NY-ESO-1) vaccine with ISCOMATRIX adjuvant versus ISCOMATRIX alone in a randomized, double-blind phase II study in participants with fully resected melanoma at high risk of recurrence. METHODS: Participants with resected stage IIc, IIIb, IIIc and IV melanoma expressing NY-ESO-1 were randomized to treatment with three doses of NY-ESO-1/ISCOMATRIX or ISCOMATRIX adjuvant administered intramuscularly at 4-week intervals, followed by a further dose at 6 months. Primary endpoint was the proportion free of relapse at 18 months in the intention-to-treat (ITT) population and two per-protocol populations. Secondary endpoints included relapse-free survival (RFS) and overall survival (OS), safety and NY-ESO-1 immunity. RESULTS: The ITT population comprised 110 participants, with 56 randomized to NY-ESO-1/ISCOMATRIX and 54 to ISCOMATRIX alone. No significant toxicities were observed. There were no differences between the study arms in relapses at 18 months or for median time to relapse; 139 vs 176 days (p=0.296), or relapse rate, 27 (48.2%) vs 26 (48.1%) (HR 0.913; 95% CI 0.402 to 2.231), respectively. RFS and OS were similar between the study arms. Vaccine recipients developed strong positive antibody responses to NY-ESO-1 (p≤0.0001) and NY-ESO-1-specific CD4+ and CD8+ responses. Biopsies following relapse did not demonstrate differences in NY-ESO-1 expression between the study populations although an exploratory study demonstrated reduced (NY-ESO-1)+/Human Leukocyte Antigen (HLA) class I+ double-positive cells in biopsies from vaccine recipients performed on relapse in 19 participants. CONCLUSIONS: The vaccine was well tolerated, however, despite inducing antigen-specific immunity, it did not affect survival endpoints. Immune escape through the downregulation of NY-ESO-1 and/or HLA class I molecules on tumor may have contributed to relapse
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