1,391 research outputs found
Metalinguistic Knowledge and Language Ability in University-Level L2 Learners
Existing research indicates that instructed learners' L2 proficiency and their metalinguistic knowledge are moderately correlated. However, the operationalization of the construct of metalinguistic knowledge has varied somewhat across studies. Metalinguistic knowledge has typically been operationalized as learners' ability to correct, describe, and explain L2 errors. More recently, this operationalization has been extended to additionally include learners' L1 language-analytic ability as measured by tests traditionally used to assess components of language learning aptitude. This article reports on a study which employed a narrowly focused measure of L2 proficiency and incorporated L2 language-analytic ability into a measure of metalinguistic knowledge. It was found that the linguistic and metalinguistic knowledge of advanced university-level L1 English learners of L2 German correlated strongly. Moreover, the outcome of a principal components analysis suggests that learners' ability to correct, describe, and explain highlighted L2 errors and their L2 language-analytic ability may constitute components of the same construct. The theoretical implications of these findings for the concept of metalinguistic knowledge in L2 learning are considered. © Oxford University Press 2007
Treasure codes: augmenting learning from physical museum exhibits through treasure hunting
Previous studies have highlighted the difficulty that designers face in creating mobile museum guides to enhance small group experiences. In this paper, we report a study exploring the potential of mobile visual recognition technology (Artcodes) to improve users’ experiences in a visitor centre. A prototype mobile guide in the form of a treasure hunt was developed and evaluated by means of a field study comparing this technology with the existing personal guided tour. The results reveal a preference for the mobile guide amongst participants and show significant learning gains from pre-test to post-test compared with the pre-existing personal tour. Our observational analyses indicate how the mobile guide can be used to improve visitors’ learning experiences by supporting active discovery and by balancing physical and digital interactions. We further expand the concept of design trajectories to consider micro-scaffolding as a way of understanding and designing future public technologies
Data, interface, security: Assembling technologies that govern the future
© 2015 Elsevier Ltd. Over the last decade, fire governance practices in the British Fire and Rescue Service (FRS) have undergone fundamental transformation. Rather than just being responded to as and when they occur, the FRS have adopted a range of anticipatory governing strategies to govern fires in anticipation of their occurence. This turn towards anticipatory governance has been facilitated in no small part by the digital infrastructure now embedded in the FRS. Composed of data, hardware, software, fibre-optic cables along with human analysts and organisational processes, this infrastructure operates to make risk projections on fire which shape and condition strategic decision making. This paper explores the operation of this digital infrastructure through the notion of interface. Drawing on empirical material relating to processes of data sourcing and risk calculation, interfaces account for the sites, moments and experiences in which human and non-human agents relate to one another in making fire risk projections. Showing relations to exist spatially, temporally and sensually, I argue that interfaces are crucial to the operation of an anticipatory security apparatus which relies on digital devices
The antimicrobial polymer PHMB enters cells and selectively condenses bacterial chromosomes
To combat infection and antimicrobial resistance, it is helpful to elucidate drug mechanism(s) of action. Here we examined how the widely used antimicrobial polyhexamethylene biguanide (PHMB) kills bacteria selectively over host cells. Contrary to the accepted model of microbial membrane disruption by PHMB, we observed cell entry into a range of bacterial species, and treated bacteria displayed cell division arrest and chromosome condensation, suggesting DNA binding as an alternative antimicrobial mechanism. A DNA-level mechanism was confirmed by observations that PHMB formed nanoparticles when mixed with isolated bacterial chromosomal DNA and its effects on growth were suppressed by pairwise combination with the DNA binding ligand Hoechst 33258. PHMB also entered mammalian cells, but was trapped within endosomes and excluded from nuclei. Therefore, PHMB displays differential access to bacterial and mammalian cellular DNA and selectively binds and condenses bacterial chromosomes. Because acquired resistance to PHMB has not been reported, selective chromosome condensation provides an unanticipated paradigm for antimicrobial action that may not succumb to resistance
Isotope Effect for the Penetration Depth in Superconductors
We show that various factors can lead to an isotopic dependence of the
penetration depth . Non-adiabaticity (Jahn-Teller crossing) leads to
the isotope effect of the charge carrier concentration and, consequently,
of in doped superconductors such as the cuprates. A general equation
relating the isotope coefficients of and of is presented for
London superconductors. We further show that the presence of magnetic
impurities or a proximity contact also lead to an isotopic dependence of
; the isotope coefficient turns out to be temperature dependent,
, in these cases. The existence of the isotope effect for the
penetration depth is predicted for conventional as well as for high-temperature
superconductors. Various experiments are proposed and/or discussed.Comment: 11 pages, 8 figures, accepted for publication in Phys. Rev.
‘What are you going to do, confiscate their passports?’ Professional perspectives on cross-border reproductive travel
Objective: This article reports findings from a UK-based study which explored the phenomenon of overseas travel for fertility treatment. The first phase of this project aimed to explore how infertility clinicians and others professionally involved in fertility treatment understand the nature and consequences of cross-border reproductive travel. Background: There are indications that, for a variety of reasons, people from the UK are increasingly travelling across national borders to access assisted reproductive technologies. While research with patients is growing, little is known about how ‘fertility tourism’ is perceived by health professionals and others with a close association with infertility patients. Methods: Using an interpretivist approach, this exploratory research included focussed discussions with 20 people professionally knowledgeable about patients who had either been abroad or were considering having treatment outside the UK. Semi-structured interviews were recorded, transcribed verbatim and subjected to a thematic analysis. Results: Three conceptual categories are developed from the data: ‘the autonomous patient’; ‘cross-border travel as risk’, and ‘professional responsibilities in harm minimisation’. Professionals construct nuanced, complex and sometimes contradictory narratives of the ‘fertility traveller’, as vulnerable and knowledgeable; as engaged in risky behaviour and in its active minimisation. Conclusions: There is little support for the suggestion that states should seek to prevent cross-border treatment. Rather, an argument is made for less direct strategies to safeguard patient interests. Further research is required to assess the impact of professional views and actions on patient choices and patient experiences of treatment, before, during and after travelling abroad
Progesterone receptors: a key for neuroprotection in experimental stroke
Progesterone receptors (PR) are expressed throughout the brain. However, their functional significance remains understudied. Here we report a novel role of PR as crucial mediators of neuroprotection using a model of transient middle cerebral artery occlusion and PR knockout mice. Six hours after ischemia, we observed a rapid increase in progesterone and 5-dihydroprogesterone, the endogenous PR ligands, a process that may be a part of the natural neuroprotective mechanisms. PR deficiency, and even haploinsufficiency, increases the susceptibility of the brain to stroke damage. Within a time window of 24 h, PR-dependent signaling of endogenous brain progesterone limits the extent of tissue damage and the impairment of motor functions. Longer-term improvement requires additional treatment with exogenous progesterone and is also PR dependent. The potent and selective PR agonist Nestorone is also effective. In contrast to progesterone, levels of the neurosteroid allopregnanolone, which modulates -aminobutyric acid type A receptors, did not increase after stroke, but its administration protected both wild-type and PR-deficient mice against ischemic damage. These results show that 1) PR are linked to signaling pathways that influence susceptibility to stroke, and 2) PR are direct key targets for both endogenous neuroprotection and for therapeutic strategies after stroke, and they suggest a novel indication for synthetic progestins already validated for contraception. Although allopregnanolone may not be an endogenous neuroprotective agent, its administration protects the brain against ischemicdamageby signaling mechanisms not involving PR. Collectively, our data clarify the relative roles of PR and allopregnanolone in neuroprotection after stroke.Fil: Liu, Ailing. Institut National de la Santé et de la Recherche Médicale; Francia. Université Paris Sud; FranciaFil: Margaill, Isabelle. Institut National de la Santé et de la Recherche Médicale; Francia. Universite de Paris V; Francia. University Paris Descartes; FranciaFil: Zhang, Shaodong. Institut National de la Santé et de la Recherche Médicale; Francia. Université Paris Sud; FranciaFil: Labombarda, Maria Florencia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de BiologÃa y Medicina Experimental. Fundación de Instituto de BiologÃa y Medicina Experimental. Instituto de BiologÃa y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de BioquÃmica Humana; ArgentinaFil: Coqueran, Bérard. Institut National de la Santé et de la Recherche Médicale; Francia. Universite de Paris V; FranciaFil: Delespierre, Brigitte. Université Paris Sud; Francia. Institut National de la Santé et de la Recherche Médicale; FranciaFil: Liere, Philippe. Université Paris Sud; Francia. Institut National de la Santé et de la Recherche Médicale; FranciaFil: Marchand Leroux, Catherine. Institut National de la Santé et de la Recherche Médicale; Francia. Universite de Paris V; FranciaFil: O’Malley, Bert W.. Baylor College of Medicine;Fil: Lydon, John P.. Baylor College of Medicine;Fil: de Nicola, Alejandro Federico. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de BiologÃa y Medicina Experimental. Fundación de Instituto de BiologÃa y Medicina Experimental. Instituto de BiologÃa y Medicina Experimental; ArgentinaFil: Sitruk Ware, Regine. The Rockefeller University; Estados UnidosFil: Mattern, Claudia. MetP Pharma AG; SuizaFil: Plotkine, Michel. Universite de Paris V; FranciaFil: Schumacher, Michael. Institut National de la Santé et de la Recherche Médicale; Francia. Université Paris Sud; FranciaFil: Guennoun, Rachida. Université Paris Sud; Francia. Institut National de la Santé et de la Recherche Médicale; Franci
Considering Intra-individual Genetic Heterogeneity to Understand Biodiversity
In this chapter, I am concerned with the concept of Intra-individual Genetic Hetereogeneity (IGH) and its potential influence on biodiversity estimates. Definitions of biological individuality are often indirectly dependent on genetic sampling -and vice versa. Genetic sampling typically focuses on a particular locus or set of loci, found in the the mitochondrial, chloroplast or nuclear genome. If ecological function or evolutionary individuality can be defined on the level of multiple divergent genomes, as I shall argue is the case in IGH, our current genetic sampling strategies and analytic approaches may miss out on relevant biodiversity. Now that more and more examples of IGH are available, it is becoming possible to investigate the positive and negative effects of IGH on the functioning and evolution of multicellular individuals more systematically. I consider some examples and argue that studying diversity through the lens of IGH facilitates thinking not in terms of units, but in terms of interactions between biological entities. This, in turn, enables a fresh take on the ecological and evolutionary significance of biological diversity
(Micro)evolutionary changes and the evolutionary potential of bird migration
Seasonal migration is the yearly long-distance movement of individuals between their breeding and wintering grounds. Individuals from nearly every animal group exhibit this behavior, but probably the most iconic migration is carried out by birds, from the classic V-shape formation of geese on migration to the amazing nonstop long-distance flights undertaken by Arctic Terns Sterna paradisaea. In this chapter, we discuss how seasonal migration has shaped the field of evolution. First, this behavior is known to turn on and off quite rapidly, but controversy remains concerning where this behavior first evolved geographically and whether the ancestral state was sedentary or migratory (Fig. 7.1d, e). We review recent work using new analytical techniques to provide insight into this topic. Second, it is widely accepted that there is a large genetic basis to this trait, especially in groups like songbirds that migrate alone and at night precluding any opportunity for learning. Key hypotheses on this topic include shared genetic variation used by different populations to migrate and only few genes being involved in its control. We summarize recent work using new techniques for both phenotype and genotype characterization to evaluate and challenge these hypotheses. Finally, one topic that has received less attention is the role these differences in migratory phenotype could play in the process of speciation. Specifically, many populations breed next to one another but take drastically different routes on migration (Fig. 7.2). This difference could play an important role in reducing gene flow between populations, but our inability to track most birds on migration has so far precluded evaluations of this hypothesis. The advent of new tracking techniques means we can track many more birds with increasing accuracy on migration, and this work has provided important insight into migration's role in speciation that we will review here
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