15,964 research outputs found
Vortex glass transition in a frustrated 3D XY model with disorder
The anisotropic frustrated three dimensional (3D) XY model with disorder in
the coupling constants is simulated as a model of a point disordered
superconductor in an applied magnetic field. From a finite size scaling
analysis of the helicity modulus it is concluded that the data is consistent
with a finite temperature transition with isotropic scaling and the correlation
length exponent is found to be \nu=1.50+/-0.12, consistent with 3D gauge glass
universality.Comment: For additional information, see
http://www.tp.umu.se/~olsson/VortexGlass.htm
All-cause mortality following a cancer diagnosis amongst multiple sclerosis patients: A Swedish population-based cohort study
Background and purpose: A reduced cancer risk amongst patients with multiple sclerosis (MS) has been reported. Theoretically, this could represent a genuine reduction in risk or, alternatively, 'diagnostic neglect', where cancer is undiagnosed when symptoms are misattributed to MS. Objective: Assess all-cause mortality risk following a cancer diagnosis in patients with MS compared with a cohort without MS. Patients: A cohort of MS patients (n = 19 364) and a cohort of the general population (n = 192 519) were extracted from national Swedish registers from 1969 to 2005. All-cause mortality after cancer in MS was compared with the general population. Poisson regression analysis was conducted in the MS and non-MS cohorts separately. The models were adjusted for follow-up duration, year at entry, sex, region and socioeconomic index. The two cohorts were combined and differences in mortality risk were assessed using interaction testing. Results: The adjusted relative risk (and 95 confidence interval) for all-cause mortality following a cancer diagnosis in MS patients (compared with MS patients without cancer) is 3.06 (2.86-3.27; n = 1768) and amongst those without MS 5.73 (5.62-5.85; n = 24 965). This lower magnitude mortality risk in the MS patients was confirmed by multiplicative interaction testing (P < 0.001). Conclusions: A consistent pattern of lower magnitude of all-cause mortality risk following cancer in MS patients for a range of organ-specific cancer types was found. It suggests that cancer diagnoses tend not to be delayed in MS and diagnostic neglect is unlikely to account for the reduced cancer risk associated with MS. The lower magnitude cancer risk in MS may be due to disease-associated characteristics or exposures. © 2015 EAN
Two phase transitions in the fully frustrated model
The fully frustrated model on a square lattice is studied by means of
Monte Carlo simulations. A Kosterlitz-Thouless transition is found at , followed by an ordinary Ising transition at a slightly
higher temperature, . The non-Ising exponents reported by
others, are explained as a failure of finite size scaling due to the screening
length associated with the nearby Kosterlitz-Thouless transition.Comment: REVTEX file, 8 pages, 5 figures in uuencoded postscrip
Identifying Agile Requirements Engineering Patterns in Industry
Agile Software Development (ASD) is gaining in popularity in today´s business world. Industry is adopting agile methodologies both to accelerate value delivery and to enhance the ability to deal with changing requirements. However, ASD has a great impact on how Requirements Engineering (RE) is carried out in agile environments. The integration of Human-Centered Design (HCD) plays an important role due to the focus on user and stakeholder involvement. To this end, we aim to introduce agile RE patterns as main objective of this paper. On the one hand, we will describe our pattern mining process based on empirical research in literature and industry. On the other hand, we will discuss our results and provide two examples of agile RE patterns. In sum, the pattern mining process identifies 41 agile RE patterns. The accumulated knowledge will be shared by means of a web application.Ministerio de Economía y Competitividad TIN2013-46928-C3-3-RMinisterio de Economía y Competitividad TIN2016-76956-C3-2-RMinisterio de Economía y Competitividad TIN2015-71938-RED
Power matters: Foucault’s pouvoir/savoir as a conceptual lens in information research and practice
© the author, 2015. Introduction. This paper advocates Foucault's notion of pouvoir/savoir (power/knowledge) as a conceptual lens that information researchers might fruitfully use to develop a richer understanding of the relationship between knowledge and power. Methods. Three of the authors’ earlier studies are employed to illustrate the use of this conceptual lens. Methodologically, the studies are closely related: they adopted a qualitative research design and made use of semi-structured and/or conversational, in-depth interviews as their primary method of data collection. The data were analysed using an inductive, discourse analytic approach. Analysis. The paper provides a brief introduction to Foucault’s concept before examining the information practices of academic, professional and artistic communities. Through concrete empirical examples, the authors aim to demonstrate how a Foucauldian lens will provide a more in-depth understanding of how particular information practices exert authority in a discourse community while other such practices may be construed as ineffectual. Conclusion. The paper offers a radically different conceptual lens through which researchers can study information practices, not in individual or acultural terms but as a social construct, both a product and a generator of power/knowledge
Power matters: The importance of foucault’s power/knowledge as a conceptual lens in km research and practice
© Emerald Group Publishing Limited. Purpose - The purpose of this paper is to engage knowledge management (KM) researchers and practitioners with Foucault’s power/knowledge lens as a way of thinking about and recognising the central role of power in organisational knowledge cultures. Design/methodology/approach - The empirical illustrations in this paper are drawn from two qualitative studies in different professional and institutional contexts (insurance and theatre work). Both studies used in-depth interviews and discourse analysis as their principal methods of data collection and analysis. Findings - The empirical examples illustrate how practitioners operate within complex power/knowledge relations that shape their practices of knowledge sharing, generation and use. The findings show how an application of the power/knowledge lens renders visible both the constraining and productive force of power in KM. Research limitations/implications - Researchers may apply the conceptual tools presented here in a wider variety of institutional and professional contexts to examine the complex and multifaceted role of power in a more in-depth way. Practical implications - KM professionals will benefit from an understanding of organisational power/knowledge relations when seeking to promote transformational changes in their organisations and build acceptance for KM initiatives. Originality/value - This paper addresses a gap in the literature around theoretical and empirical discussions of power as well as offering an alternative to prevailing resource-based views of power in KM
Testing reproductive allometry in fish
Abstract
Energy allocation models have proved useful for clarifying the ecological mechanisms which influence growth and reproduction schemes in species with indeterminate growth and for understanding how traits correlate with generate the life history of specific species. In view of the need to understand how exploitation affects species for which few data on key population parameters such as reproductive potential and population growth rate are available, it would be helpful if simple energy allocation schemes parametrized by easily obtainable data could be used to estimate parameters such as reproductive effort and output. Testing the predictions of three such models on fecundity data from a range of species, we show how the simplifications required in a generalized energy allocation scheme are reflected in the deviations between model predictions and empirical data, and discuss the validity of the assumptions underlying these models. We caution against over-reliance on generalized and simplified models to predict reproductive effort.</jats:p
Critical exponent \eta_\phi of the Lattice London Superconductor and vortex loops in the 3D XY model
The anomalous dimension of the lattice London superconductor is determined
from finite size scaling of the susceptibility to be \eta_\phi = -0.79(1).
Indirect determinations of \eta_\phi from properties of the vortex loops in the
3D XY model are also attempted, but it is found that the results are sensitive
to details in the simulations related to vortex loop intersections. It is
suggested that the same value of \eta_\phi can at most be obtained from vortex
loop properties in the limit of low vortex density
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