3,487 research outputs found

    Photoelectro-chemical properties of anilino squaraine derivatives in LB films

    No full text
    Photocurrent generation from Langmuir-Blodgett (LB) overlays on indium tin oxide (ITO) electrodes, where the active components are 2,4-bis[4-(dibutylamino)-2-hydroxyphenyl]squaraine (1) and the unsubstituted analogue, 2,4-bis[4-(dibutylamino)phenyl]squaraine (2), have been investigated. Dye 1 shows improved behaviour compared with the latter and differences in performance are attributed to a modified aggregate structure, this being indicated by variations in the LB film spectra. The photocurrent generation is enhanced by the presence of electron accepters, e.g. N,N'-dimethyl-4,4'-bipyridinium diiodide (MV2+), but quenched by electron donors, e.g. hydroquinone (HQ). The concentration dependence is reported

    LB v YD 2009 5 SA 463 (T) / YD v LB (A) 2009 5 SA 479 (NGP)

    No full text
    When LB v YD (2009 5 SA 463 (T)) was heard by the High Court, an opportunity presented itself for the Court to adjudicate once and for all on the thorny issue of compelling for DNA testing. In ruling on the matter, Murphy J gave an insightful and eloquent judgment, (Heaton J “October to December Persons” 2009 (4) JQR par 2.1 disagrees with this assessment) however, his failure in YD v LB (A) (2009 5 SA 479 (NGP)) to grant leave to appeal, no matter how well founded his decision, deprived South Africans of increased legal certainty on the matter. (Heaton agrees with this statement.) In this note an attempt will be made to highlight a number of important aspects of the case and to explain why leave to appeal should have been granted in YD v LB (A) (supra)

    The contribution of exploratory talk to mathematical learning

    No full text
    This short report illustrates the relationship between the occurrence of 'exploratory talk' in collaborative peer groups in secondary mathematics classrooms and the extent to which pupils and teacher share common goals relating to small group work

    Nonadaptive Amino Acid Convergence Rates Decrease over Time.

    No full text
    Convergence is a central concept in evolutionary studies because it provides strong evidence for adaptation. It also provides information about the nature of the fitness landscape and the repeatability of evolution, and can mislead phylogenetic inference. To understand the role of adaptive convergence, we need to understand the patterns of nonadaptive convergence. Here, we consider the relationship between nonadaptive convergence and divergence in mitochondrial and model proteins. Surprisingly, nonadaptive convergence is much more common than expected in closely related organisms, falling off as organisms diverge. The extent of the convergent drop-off in mitochondrial proteins is well predicted by epistatic or coevolutionary effects in our "evolutionary Stokes shift" models and poorly predicted by conventional evolutionary models. Convergence probabilities decrease dramatically if the ancestral amino acids of branches being compared have diverged, but also drop slowly over evolutionary time even if the ancestral amino acids have not substituted. Convergence probabilities drop-off rapidly for quickly evolving sites, but much more slowly for slowly evolving sites. Furthermore, once sites have diverged their convergence probabilities are extremely low and indistinguishable from convergence levels at randomized sites. These results indicate that we cannot assume that excessive convergence early on is necessarily adaptive. This new understanding should help us to better discriminate adaptive from nonadaptive convergence and develop more relevant evolutionary models with improved validity for phylogenetic inference

    Learning theories and interprofessional education: a user's guide

    No full text
    There is increasing interest in the theoretical underpinning of interprofessional education (IPE) and writers in this field are drawing on a wide range of disciplines for theories that have utility in IPE. While this has undoubtedly enriched the research literature, for the educational practitioner, whose aim is to develop and deliver an IPE curriculum that has sound theoretical underpinnings, this plethora of theories has become a confusing, and un-navigable quagmire. This article aims to provide a compass for those educational practitioners by presenting a framework that summarizes key learning theories used in IPE and the relationship between them. The study reviews key contemporary learning theories from the wider field of education used in IPE and the explicit applications of these theories in the IPE literature to either curriculum design or programme evaluation. Through presenting a broad overview and summary framework, the study clarifies the way in which learning theories can aid IPE curriculum development and evaluation. It also highlights areas where future theoretical development in the IPE field is required

    Photoelectrochemistry of Langmuir-Blodgett films of a C-60 iminodiacetic acid ester derivative on ITO electrodes

    No full text
    The photoelectrochemical response of a C-60 iminodiacetic acid ester derivative (C(60)IDA), deposited on ITO electrodes by means of the Langmuir-Blodgett technique, has been investigated. The anodic photocurrent observed on the modified electrode corresponds to an electron transfer from the electrolyte through the LB film to the electrode. The action spectrum of photocurrent indicates C60IDA as the photoactive species in the photoinduced electron transfer process. Positive bias voltage, reducing agent and higher pH of the solution are beneficial factors for generating higher photocurrent. The quantum yield for photocurrent generation is 0.94% and can be raised to 3.40% under favorable conditions. (C) 1998 Elsevier Science S.A. All rights reserved.Materials Science, MultidisciplinaryPhysics, Condensed MatterPolymer ScienceSCI(E)EI9ARTICLE3223-2279

    Theory as Method in Research : On Bourdieu, Education and Society

    No full text
    While education researchers have drawn on the work of a wide diversity of theorists over the years, much contemporary theory building in these areas has revolved around the work of Pierre Bourdieu. Theory as Method aims to develop the capacity of students, researchers and teachers to successfully put Bourdieu’s ideas to work in their own research and prepare them effectively for conducting Masters and Doctoral scholarships. Contextualising the various concepts within the broader oeuvre of Bourdieu’s theoretical approach, Theory as Method will be a useful guide for practitioners, student teachers, researchers, policy makers and academics

    Factorization of weakly compact operators between Banach spaces and Fréchet or (LB)-spaces

    No full text
    [EN] In this note we show that weakly compact operators from a Banach space X into a complete (LB)-space E need not factorize through a reflexive Banach space. If E is a Fréchet space, then weakly compact operators from a Banach space X into E factorize through a reflexive Banach space. The factorization of operators from a Fréchet or a complete (LB)-space into a Banach space mapping bounded sets into relatively weakly compact sets is also investigated.The research of the first author was partially supported by MEC and FEDER Project MTM2010-15200 and by GV Project Prometeo/2008/101. The support of the University of Aberdeen and the Universidad Polit´ecnica of Valencia is gratefully acknowledged.Bonet Solves, JA.; Wright, JM. (2012). Factorization of weakly compact operators between Banach spaces and Fréchet or (LB)-spaces. Matematicki Vesnik. 64(4):330-335. https://riunet.upv.es/handle/10251/58753S33033564
    corecore