16,671 research outputs found

    Verbal paired associates and the hippocampus: The role of scenes

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    It is widely agreed that patients with bilateral hippocampal damage are impaired at binding pairs of words together. Consequently, the verbal paired associates (VPA) task has become emblematic of hippocampal function. This VPA deficit is not well understood and is particularly difficult for hippocampal theories with a visuospatial bias to explain (e.g., cognitive map and scene construction theories). Resolving the tension among hippocampal theories concerning the VPA could be important for leveraging a fuller understanding of hippocampal function. Notably, VPA tasks typically use high imagery concrete words and so conflate imagery and binding. To determine why VPA engages the hippocampus, we devised an fMRI encoding task involving closely matched pairs of scene words, pairs of object words, and pairs of very low imagery abstract words. We found that the anterior hippocampus was engaged during processing of both scene and object word pairs in comparison to abstract word pairs, despite binding occurring in all conditions. This was also the case when just subsequently remembered stimuli were considered. Moreover, for object word pairs, fMRI activity patterns in anterior hippocampus were more similar to those for scene imagery than object imagery. This was especially evident in participants who were high imagery users and not in mid and low imagery users. Overall, our results show that hippocampal engagement during VPA, even when object word pairs are involved, seems to be evoked by scene imagery rather than binding. This may help to resolve the issue that visuospatial hippocampal theories have in accounting for verbal memory

    What next for English teacher education?

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    Vol. 1. No. 1 APR 2011 Professor Meg Maguire from King's College London has been a guest speaker at one of the seminars run by the Secondary Research Group at the School of Education and Communities. Her research is in the sociology of education, urban education and policy. She has a long-standing interest in the lives of teachers and has explored issues of class, race, gender and age in teachers' social and professional worlds. Meg has conducted Economic and Social Research Council (ESRC)-funded research into the experiences of minority ethnic trainee teachers, post-compulsory transitions and multi-agency policy in challenging school exclusion in urban primary schools. In this article she offers some thoughts on the Schools White Paper (DfE 2010) and its potential impact on teacher education

    Where do young people work?

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    The current policy intention, that all young people remain in some form of accredited education or training to the age of 18 by 2015, poses significant challenges. The jobs without training (JWT) group includes young people who are in full-time work and not in receipt of training leading to National Vocational Qualification level 2 (or above); knowing more about them and meeting their needs will be crucial for the delivery of the Raising of the Participation Age agenda. This paper presents findings from a study of the JWT group, from the perspective of employers, which formed part of wider research including policymakers, young people and their parents. It concludes that the label JWT fails to describe the heterogeneity of this group and the needs of those who employ them. If routes into the labour market remain open to 16- and 17-year-olds, attention must be given to supporting young people's transitions through a more active role in job placement and securing greater support for formalised training

    The volumetric rate of calcium-rich transients in the local universe

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    We present a measurement of the volumetric rate of `calcium-rich' optical transients in the local universe, using a sample of three events from the Palomar Transient Factory (PTF). This measurement builds on a detailed study of the PTF transient detection efficiencies, and uses a Monte Carlo simulation of the PTF survey. We measure the volumetric rate of calcium-rich transients to be higher than previous estimates: 1.210.39+1.13×1051.21^{+1.13}_{-0.39}\times10^{-5} events yr1^{-1} Mpc3^{-3}. This is equivalent to 33-94% of the local volumetric type Ia supernova rate. This calcium-rich transient rate is sufficient to reproduce the observed calcium abundances in galaxy clusters, assuming an asymptotic calcium yield per calcium-rich event of ~0.05M\mathrm{M}_{\odot}. We also study the PTF detection efficiency of these transients as a function of position within their candidate host galaxies. We confirm as a real physical effect previous results that suggest calcium-rich transients prefer large physical offsets from their host galaxies.Comment: Accepted for publication in ApJ. 9 pages, 5 figure

    The impact and penetration of location-based services

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    Since the invention of digital technology, its development has followed an entrenched path ofminiaturisation and decentralisation with increasing focus on individual and niche applications. Computerhardware has moved from remote centres to desktop and hand held devices whilst being embedded invarious material infrastructures. Software has followed the same course. The entire process has convergedon a path where various analogue devices have become digital and are increasingly being embedded inmachines at the smallest scale. In a parallel but essential development, there has been a convergence ofcomputers with communications ensuring that the delivery and interaction mechanisms for computersoftware is now focused on networks of individuals, not simply through the desktop, but in mobilecontexts. Various inert media such as fixed television is becoming more flexible as computers and visualmedia are becoming one.With such massive convergence and miniaturisation, new software and new applications define the cuttingedge. As computers are being increasingly tailored to individual niches, then new digital services areemerging, many of which represent applications which hitherto did not exist or at best were rarely focusedon a mass market. Location based services form one such application and in this paper, we will bothspeculate on and make some initial predictions of the geographical extent to which such services willpenetrate different markets. We define such services in detail below but suffice it to say at this stage thatsuch functions involve the delivery of traditional services using digital media and telecommunications.High profile applications are now being focused on hand held devices, typically involving information onproduct location and entertainment but wider applications involve fixed installations on the desktop whereservices are delivered through traditional fixed infrastructure. Both wire and wireless applications definethis domain. The market for such services is inevitably volatile and unpredictable at this early stage but wewill attempt here to provide some rudimentary estimates of what might happen in the next five to tenyears.The ?network society? which has developed through this convergence, is, according to Castells (1989,2000) changing and re-structuring the material basis of society such that information has come todominate wealth creation in a way that information is both a raw material of production and an outcome ofproduction as a tradable commodity. This has been fuelled by the way technology has expanded followingMoore?s Law and by fundamental changes in the way telecommunications, finance, insurance, utilitiesand so on is being regulated. Location based services are becoming an integral part of this fabric and thesereflect yet another convergence between geographic information systems, global positioning systems, andsatellite remote sensing. The first geographical information system, CGIS, was developed as part of theCanada Land Inventory in 1965 and the acronym ?GIS? was introduced in 1970. 1971 saw the firstcommercial satellite, LANDSAT-1. The 1970s also saw prototypes of ISDN and mobile telephone and theintroduction of TCP/IP as the dominant network protocol. The 1980s saw the IBM XT (1982) and thebeginning of de-regulation in the US, Europe and Japan of key sectors within the economy. Finally in the 1990s, we saw the introduction of the World Wide Web and the ubiquitous pervasion of business andrecreation of networked PC?s, the Internet, mobile communications and the growing use of GPS forlocational positioning and GIS for the organisation and visualisation of spatial data. By the end of the 20thcentury, the number of mobile telephone users had reached 700 million worldwide. The increasingmobility of individuals, the anticipated availability of broadband communications for mobile devices andthe growing volumes of location specific information available in databases will inevitably lead to thedemand for services that will deliver location related information to individuals on the move. Suchlocation based services (LBS) although in a very early stage of development, are likely to play anincreasingly important part in the development of social structures and business in the coming decades.In this paper we begin by defining location based services within the context we have just sketched. Wethen develop a simple model of the market for location-based services developing the standard non-linearsaturation model of market penetration. We illustrate this for mobile devices, namely mobile phones in thefollowing sections and then we develop an analysis of different geographical regimes which arecharacterised by different growth rates and income levels worldwide. This leads us to speculate on theextent to which location based services are beginning to take off and penetrate the market. We concludewith scenarios for future growth through the analogy of GIS and mobile penetration

    Do Small-mass Neutrinos participate in Gauge Transformations?

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    Neutrino oscillation experiments presently suggest that neutrinos have a small but finite mass. If neutrinos are to have mass, there should be a Lorentz frame in which they can be brought to rest. This paper discusses how Wigner's little groups can be used to distinguish between massive and massless particles. We derive a representation of the SL(2,c) group which separates out the two sets of spinors contained therein. One set is gauge dependent. The other set is gauge-invariant and represents polarized neutrinos. We show that a similar calculation can be done for the Dirac equation. In the large-momentum/zero-mass limit, the Dirac spinors can be separated into large and small components. The large components are gauge invariant, while the small components are not. These small components represent spin-12\frac{1}{2} non-zero mass particles. If we renormalize the large components, these gauge invariant spinors again represent the polarization of neutrinos. Massive neutrinos cannot be invariant under gauge transformations.Comment: 15 page

    Understanding Surprise: Can Less Likely Events Be Less Surprising?

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    Surprise is often thought of as an experience that is elicited following an unexpected event. However, it may also be the case that surprise stems from an event that is simply difficult to explain. In this paper, we investigate the latter view. Specifically, we question why the provision of an enabling factor can mitigate perceived surprise for an unexpected event despite lowering the overall probability of that event. One possibility is that surprise occurs when a person cannot rationalise an outcome event in the context of the scenario representation. A second possibility is that people can generate plausible explanations for unexpected events but that surprise is experienced when those explanations are uncertain. We explored these hypotheses in an experiment where a first group of participants rated surprise for a number of scenario outcomes and a second group rated surprise after generating a plausible explanation for those outcomes. Finally, a third group of participants rated surprise for the both the original outcomes and the reasons generated for those outcomes by the second group. Our results suggest that people can come up with plausible explanations for unexpected events but that surprise results when these explanations are uncertain
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