80 research outputs found
Synergy and Group Size in Microbial Cooperation
Get PDFMicrobes produce many molecules that are important for their growth and development, and the exploitation of these secretions by nonproducers has recently become an important paradigm in microbial social evolution. Although the production of these public-goods molecules has been studied intensely, little is known of how the benefits accrued and the costs incurred depend on the quantity of public-goods molecules produced. We focus here on the relationship between the shape of the benefit curve and cellular density, using a model assuming three types of benefit functions: diminishing, accelerating, and sigmoidal (accelerating and then diminishing). We classify the latter two as being synergistic and argue that sigmoidal curves are common in microbial systems. Synergistic benefit curves interact with group sizes to give very different expected evolutionary dynamics. In particular, we show that whether and to what extent microbes evolve to produce public goods depends strongly on group size. We show that synergy can create an "evolutionary trap" that can stymie the establishment and maintenance of cooperation. By allowing density-dependent regulation of production (quorum sensing), we show how this trap may be avoided. We discuss the implications of our results on experimental design.</p
Colour normalisation to reduce inter-patient and intra-patient variability in microaneurysm detection in colour retinal images
No full textImages of the human retina vary considerably in their appearance depending on the skin pigmentation (amount of melanin) of the subject. Some form of normalisation of colour in retinal images is required for automated analysis of images if good sensitivity and specificity at detecting lesions is to be achieved in populations involving diverse races. Here we describe an approach to colour normalisation by shade-correction intra-image and histogram normalisation inter-image. The colour normalisation is assessed by its effect on the automated detection of microaneurysms in retinal images. It is shown that the Na¨ıve Bayes classifier used in microaneurysm detection benefits from the use of features measured over colour normalised images
Trade unions and producer co-operatives
No full textAlthough the trade union and producer co-operative movements have similar historical roots and share many common aims, the relationships between the two have often been uneasy. As the number of new producer co-operatives has recently increased rapidly in many Western countries this paper aims to reexamine the relationship between the two movements. The paper is in two parts. The first part re-appraises some of the arguments against trade unions supporting producer co-operatives. The second part describes the role that trade unions could play both within individual producer co-operatives and in the wider movement. The author concludes that both movements have much to gain from closer collaboration
Trade union managers: invisible actors in Trade union dramas
Get PDFThis paper is concerned with a group of people who are almost entirely absent
from the literature on trade union governance, trade union managers. It looks
at various governance models and seeks to make links between that literature
and analogous literature in the management field, in particular between that
on the polyarchal theory of trade union organisation and that on stakeholder
management. It concludes that managers have become visible and that they
seek to manage their organisations subject to a number of constraints arising
in some cases from the fact that management remains a somewhat
problematic concept in unions. Although the values of trade union managers
result in their taking a positive attitude to the democratic process, the
boundaries between their roles and the roles of elected activists in the
governance structures are unclear and are consequently contested.School of Managemen
Assessing complexity and causality in heart period variability through a model-free data-driven multivariate approach
No full textThe aim of this study is to emphasize the importance of model-free data-driven mul- tivariate approaches in describing HP variability and cardiovascular control mechanisms responsible for inducing HP changes via modifications of different cardiovascular vari- ables such as SAP and RESP. The goal was achieved through the application, a previously proposed model-free data-driven multivariate framework devised to assess complexity and causality over a multivariate set composed by several, simultaneously recorded, car- diovascular variability series (Porta et al., 2014). The approach was applied to assess the complexity of the cardiac control, through the evaluation of the amount of irregularity of HP variability in a multivariate space accounting for HP, SAP, and RESP; the degree of involvement of the cardiac baroreflex and cardiopulmonary pathway in governing cardio- vascular interactions, through the evaluation of the strength of the causal link from SAP and RESP to HP variability. Modifications of complexity and causality during supine rest- ing condition (REST) and during the orthostatic challenge resulting from active standing (STAND) were quantified as a function of age
Public service spin-outs in the UK: towards a theoretical understanding of the spin-out process
No full textSince the election of the Labour government in 1997 and its vision of the ‘Third Way’, the UK government has been keen to support social enterprise and to utilise the third sector in welfare delivery. Over the past few years the policy environment in the UK has sought to encourage public sector workers to ‘spin-out’ the services that they deliver into social enterprises. The research reported in this paper draws on semi-structured interviews with eleven representatives across four local authorities (LA) in the UK that are spinning out a public service into a social enterprise. The services being spun out operate across four different sectors, which allows the research to identify the common experiences and barriers in spinning out. The analysis is underpinned by a theoretical model of public/third sector collaboration by Takahashi and Smutny’s (2002), later adapted by Cornforth et al (2013). We present an alternative version of this framework based on public sector spin outs. In doing so, the research identified that there are significant barriers facing public services that seek to spin-out as social enterprises and the challenges that this brings to LAs in relation to managing the process. Issues around the sustainability of the ‘business case’ of the spin-outs proved to be the main problem, along with the difficulties of maintaining service provision during the transition phas
Relative proximity of chromosome territories influences chromosome exchange partners in radiation-induced chromosome rearrangements in primary human bronchial epithelial cells
Get PDFCopyright © 2013 The Authors. This article is made available through the Brunel Open Access Publishing Fund. This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-No Derivative Works License, which permits non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.Copyright © 2013 The Authors. It is well established that chromosomes exist in discrete territories (CTs) in interphase and are positioned in a cell-type specific probabilistic manner. The relative localisation of individual CTs within cell nuclei remains poorly understood, yet many cancers are associated with specific chromosome rearrangements and there is good evidence that relative territorial position influences their frequency of exchange. To examine this further, we characterised the complexity of radiation-induced chromosome exchanges in normal human bronchial epithelial (NHBE) cells by M-FISH analysis of PCC spreads and correlated the exchanges induced with their preferred interphase position, as determined by 1/2-colour 2D-FISH analysis, at the time of irradiation. We found that the frequency and complexity of aberrations induced were reduced in ellipsoid NHBE cells in comparison to previous observations in spherical cells, consistent with aberration complexity being dependent upon the number and proximity of damaged CTs, i.e. lesion proximity. To ask if particular chromosome neighbourhoods could be identified we analysed all radiation-induced pair-wise exchanges using SCHIP (statistics for chromosome interphase positioning) and found that exchanges between chromosomes (1;13), (9;17), (9;18), (12;18) and (16;21) all occurred more often than expected assuming randomness. All of these pairs were also found to be either sharing similar preferred positions in interphase and/or sharing neighbouring territory boundaries. We also analysed a human small cell lung cancer cell line, DMS53, by M-FISH observing the genome to be highly rearranged, yet possessing rearrangements also involving chromosomes (1;13) and (9;17). Our findings show evidence for the occurrence of non-random exchanges that may reflect the territorial organisation of chromosomes in interphase at time of damage and highlight the importance of cellular geometry for the induction of aberrations of varying complexity after exposure to both low and high-LET radiation.Department of Healt
A Discursive Approach to the Registration Debate Working with Texts; Thinking Ethics.
Get PDFCounsellors are currently considering impending registration. This important decision is being made in the context of wider changes that also affect the profession: poststructural versions of subjectivity; potential environmental collapse and increasing regimes of accountability. This article takes a closer look at the registration debate with these concerns in mind. It applies a critical, Foucauldian, discursive approach to two relevant documents: the Health Practitioners Competence Assurance Act 2003 (HPCAA) and the New Zealand Association of Counsellors (NZAC) Code of Ethics 2002 (the Code). Although these documents have different functions, both impinge upon counselling practice. A comparison foregrounds some ethical discrepancies and raises the question of whether registration under the Act is even possible without a significant rewrite of the NZAC Code. The article lays out some areas of divergence in the hope that they may be useful points of reference in future negotiations. [ABSTRACT FROM AUTHOR] Copyright of New Zealand Journal of Counselling is the property of New Zealand Association of Counsellors and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.
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