484 research outputs found

    The population dynamics and growth of the freshwater crayfish Austvopotamobius pallipes in an aqueduct in Northumbria

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    Despite the wide distribution and abundance of the freshwater crayfish Austropotcmobius pallipes in Britain, little is known of its population biology. The dynamics and growth of a Northumbrian population of A. pallipes were studied using an intensive-mark- recapture programme. The seasonal timing of moulting and reproduction was found to be predictable and probably related to water temperature. Stomach contents showed crayfish to be omnivorous, with plant material forming the bulk of the diet. Population size, survival and recruitment were estimated from mark- recapture data at frequent intervals. Two principal types of mortality were identified: moult-associated mortality, which was relatively intense and of short (2-3 weeks) duration, and overwinter mortality, which operated at a much lower estimated weekly rate over a period of some 30 weeks. Mortality was shown to be highly variable throughout the year. Population size generally showed a midsummer peak as recruitment into the catchable size classes occurred. Thereafter numbers declined slightly towards the end of the growth season, followed by an overwinter decline of some 50% of total numbers. Longevity was estimated to be at least eleven years. The relationship between size, age and weight was established and males shown to have faster growth rates than females after the size of sexual maturity. Growth increments and moult frequency were shown to differ between the sexes and according to body size. Reproductive females omitted one moult while carrying eggs. Growth rates were depressed by the parasite Thelohania oonteoeani and by the regeneration of a major chela. The fecundity of females and the probability of being reproductive increased with body size. The annual production of the study population was estimated at 196.49 kg ha(^-1) in 1977, 116.80 kg ha(^-1) in 1978 and 87.79 kg ha(^-1) in 1979. Detailed life histories of many marked individuals were collected which support the conclusions drawn at the population level

    Queering queer theory in management and organization studies: notes toward queering heterosexuality

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    This article suggests new possibilities for queer theory in management and organization studies (MOS). MOS has tended to use queer theory as a conceptual resource for studying the workplace experience of ‘minorities’ such as gay men, lesbians and those identifying as bisexual or transgender (LGBT), often focusing on how heteronormativity shapes the discursive constitution of sexualities and genders coded as LGBT. But this deployment is crucial and apposite but it can limit the analytical reach of queer theory, ignoring other objects of analysis such as heterosexuality. Potentially, MOS queer theory scholarship could be vulnerable to criticism about ignoring queer theory as a productive site for acknowledging heterosexuality’s coercive aspects but also its non-normative forms. As such, the principal contribution of this article is twofold. First, it proposes a queering of queer theory in MOS, whereby scholars are alert to and question the potential normativities that MOS queer theory research can produce, opening up a space for exploring how heterosexuality can be queered. Second, we show how queering heterosexuality can be another site where queer theory and politics can come together in the MOS field through a shared attempt to rupture sexual and gender binaries, and challenge normative social relations. This article concludes by outlining the political implications of queering heterosexuality for generating modes of organizing in which heterosexuality can be experienced as non-normative and how it might rupture and dismantle heteronormativity

    The World of UCL

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    From its foundation in 1826, UCL embraced a progressive and pioneering spirit. It was the first university in England to admit students regardless of religion and made higher education affordable and accessible to a much broader section of society. It was also effectively the first university to welcome women on equal terms with men. From the outset UCL showed a commitment to innovative ideas and new methods of teaching and research. This book charts the history of UCL from 1826 through to the present day, highlighting its many contributions to society in Britain and around the world. It covers the expansion of the university through the growth in student numbers and institutional mergers. It documents shifts in governance throughout the years and the changing social and economic context in which UCL operated, including challenging periods of reconstruction after two World Wars. Today UCL is one of the powerhouses of research and teaching, and a truly global university. It is currently seventh in the QS World University Rankings. This completely revised and updated edition features a new chapter based on interviews with key individuals at UCL. It comes at a time of ambitious development for UCL with the establishment of an entirely new campus in East London, UCL East, and Provost Michael Arthur’s ‘UCL 2034’ strategy which aims to secure the university’s long-term future and commits UCL to delivering global impact

    The normalisation of 'excessive' workforce drug testing?

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    In 'The normalization of 'sensible' recreational drug use' Parker, Williams and Aldridge (2002) present data on illegal drug use by adolescents and young adults in the UK. They argue that it is both widespread and largely socially benign - ie, normal. We contrast this 'normalisation' thesis with evidence of an increase in the introduction of drug policies -- and drug testing -- in British organisations. Such policies construct employee drug use as excessive enough to necessitate heightened management vigilance over workers, in order to preserve corporate interests. These contrasting representations of drug use inspire our discussion. We deploy the normal/ excessive couplet to unpick drug taking, to examine organisational drug policies and to comment upon emerging and potential resistance to these policies. Our contribution is to suggest that each of these activities can be understood as simultaneously normal and excessive, in an area where orthodox and critical analyses alike tend to be far more dualistic

    Imaging right ventricular function to predict outcome in patients treated for pulmonary hypertension

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    Pulmonary arterial hypertension (PAH) is a rare but devastating disorder of the pulmonary vasculature characterised pathologically by progressive intimal obliteration and vascular remodelling leading to increased pulmonary vascular resistance (PVR) and elevation in pulmonary arterial pressure (PAP), and clinically by functional impairment from breathlessness and ultimately death from right ventricular failure. Whilst the initial insult occurs in the pulmonary circulation, it is increasing recognised that survival relates to the ability of the right ventricle (RV) to adapt to this increased afterload. Despite a number of therapeutic advances in recent years, long-term survival remains poor, quality of life impaired by functional limitation and progression to RV failure often inevitable. In contrast, pulmonary hypertension (PH) related to chronic lung disease is relatively common, but is usually mild in severity with largely preserved RV function. The development of PH is however associated with greater functional impairment and worse survival and at present other than referral for lung transplantation there are no therapeutic options. Severe PH associated with lung disease is relatively rare, but shares many of the characteristics with PAH with more severe RV dysfunction and significant morbidity and mortality. It is also increasingly recognised in data from large PH registries, that increasing overlap exists between the two conditions, and what represents PAH with co-morbid lung disease (and therefore should receive specific PAH therapies) and what is PH secondary to lung disease (and therefore should not) increasingly muddied. What is clear is the critical role the RV plays in determining outcome in PH, but despite this studies on the impact of current therapies on RV function are few, and improvement or preservation of RV function is not an accepted clinical endpoint in pharmaceutical trials. Current methods of monitoring patient response to therapies are suboptimal, such as the established and commonly employed six minute walk distance (6MWD). The complex anatomy of the RV makes assessment of its function by modalities such as echocardiogram difficult. The development of simple, reproducible measures of RV function will both improve monitoring of PH patients but also facilitate acceptance of routine assessment of RV function in both clinical practice and pharmaceutical trials, and hopefully establish the optimal approach to RV dysfunction in PAH. Cardiac magnetic resonance imaging (CMR) is particularly suited to interrogating RV function, and has recently been established in the literature to provide prognostic significance in a number of disease states including PAH. At present, however, it is unclear what the optimal method of assessing RV function is, with a number of indices assessed by varying modalities associated with prognosis and therapeutic response in PAH. Recently research interest has developed in the potential utility of RV-arterial coupling in PH. From physiological principles, this metric of RV function has potential superiority over commonly employed indices such as RVEF or right atrial pressure (RAP) as it is less preload dependent. Its clinical use however is limited due to the need for instantaneous pressure-volume loops at varying levels of load in its derivation. It is however possible to estimate non-invasively by CMR. The aim of the work described by this thesis was to provide clarity on the optimal method of determining and monitoring RV dysfunction in PAH patients, and contrast this to patients with severe PH associated with lung disease treated with PAH therapies, where the aetiology of PH differs and utility of CMR to characterise RV function has not been explored. In chapter 3 PAH therapies given to severe PH/lung disease patients resulted in improvements in 6MWD (average ∆6MWD 24m, p=0.032), and NTproBNP (average ∆NTproBNP -396pg/mL, p=0.008), but to a lesser extent than IPAH patients. CMR imaging demonstrated that RV dysfunction (assessed by RV ejection fraction (RVEF), stroke volume (SV) and increased RV volumes) was prevalent, predicted prognosis in both conditions, and could be used to detect PH in lung disease by either measures of pulmonary vascular stiffness (relative area change of main pulmonary artery – RAC MPA) or RV mass (RVM). In Chapter 4, invasive pressure (Ees/Ea-P) and non-invasive volume (SV/ESV) estimates of RV-arterial coupling (determined by right heart catheterisation and CMR) were compared to other metrics of RV function in normal subjects, PAH and PH associated with lung disease patients as prognostic variables. Severe PH/lung disease patients displayed impaired RV adaptation in comparison to IPAH subjects, Ees/Ea-P 1.07 versus 1.37mmHg/mL, p=0.020. RV-arterial coupling estimated by the pressure method did not predict survival, but when estimated by the volume method (SV/ESV) did. Both RVEF and SV/ESV were independent predictors of outcome (HR 0.958, p=0.006 and HR 0.329, p=0.002 respectively). Invasive measures of RV function therefore provided no prognostic advantage over the more patient acceptable CMR. Finally in chapter 5, improvement in RV-arterial coupling assessed by CMR (SV/ESV) was seen after commencing PAH therapy (0.461 to 0.616, p=0.036). Survival was poorer in those with a fall in either RVEF or SV/ESV during therapy, with no superiority of either method of determining prognosis (Logrank p=0.002 for both). Change in RV function poorly related to change in 6MWD but closely related to change in NTproBNP. ∆NTproBNP but not ∆6MWD was an independent predictor of survival (HR 1.622 p=0.024 and HR 0.995 p=0.129 respectively) and therefore a useful monitoring tool of RV function and therapy response for the clinic. The results described in this thesis therefore suggest that RV function to predict outcome in patients with PH during treatment follow up is best determined by CMR imaging of RVEF or SV/ESV, with no clear benefit of re-evaluating invasive haemodynamics or pressure estimates of RV-arterial coupling

    Activation of the glycosyl-phosphatidylinositol-anchored membrane dipeptidase upon release from pig kidney membranes by phospholipase C

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    Incubation of pig kidney microvillar membranes with Bacillus thuringiensis or Staphylococcus aureus phosphatidylinositol-specific phospholipase C (PI-PLC) resulted in the release of a number of glycosyl-phosphatidylinositol (GPI)-anchored hydrolases, including alkaline phosphatase (EC 3.1.3.1), amino-peptidase P (EC 3.4.11.9), membrane dipeptidase (EC 3.4.13.19), 5'-nucleotidase (EC 3.1.3.5) and trehalase (EC 3.2.1.28). Of these five ectoenzymes only for membrane dipeptidase was there a significant (approx. 100%) increase in enzymic activity upon release from the membrane. Maximal activation occurred at a PI-PLC concentration 10-fold less than that required for maximal release. In contrast solubilization of the membranes with n-octyl beta-D-glucopyranoside had no effect on the enzymic activity of membrane dipeptidase. A competitive e.l.i.s.a. with a polyclonal antiserum to membrane dipeptidase indicated that the increase in enzymic activity was not due to an increase in the amount of membrane dipeptidase protein. Although PI-PLC cleaved the GPI anchor of the affinity-purified amphipathic form of pig membrane dipeptidase there was no concurrent increase in enzymic activity. In the absence of PI-PLC, membrane dipeptidase in the microvillar membranes hydrolysed Gly-D-Phe with a Km of 0.77 mM and a Vmax. of 602 nmol/min per mg of protein. However, in the presence of a concentration of PI-PLC which caused maximal release from the membrane and maximal activation of membrane dipeptidase the Km was decreased to 0.07 mM while the Vmax. remained essentially unchanged at 624 nmol/min per mg of protein. Overall these results suggest that cleavage by PI-PLC of the GPI anchor on membrane dipeptidase may relax conformational constraints on the active site of the enzyme which exist when it is anchored in the lipid bilayer, thus resulting in an increase in the affinity of the active site for substrate

    Dangerous work: The gendered nature of bullying in the context of higher education

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    This paper discusses results from a research project which set out to investigate gender differences in the nature and experience of bullying within the higher education sector. Gender differences emerged in the form and perception of bullying as well as in target response. Results also indicate that, irrespective of gender, bullies can capture and subvert organizational structures and procedures (official hierarchies, mentoring systems, probationary reviews) to further their abuse of the target and to conceal aggressive intent. These outcomes are discussed in relation to gendered assumptions behind management practices and in relation to the masculinist ethic that underpins many higher education management initiatives. Overall, results indicate that bullying cannot be divorced from gender and that such behaviour needs to be seen in a gendered context

    Women’s experiences of menopause at work and performance management

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    Presenting findings from our global evidence review of menopause transition and economic participation emboldened us to establish a menopause policy at the university where we all worked at the time. Our report was published in July 2017 and the policy was in place by November that year. Our critical reflection on this activism focuses on issues that are not commonly recognized around such interventions, and which we ourselves have only been able to acknowledge through engaged action. Challenges remain in normalizing menopause in organizations, specifically around gendered ageism and performance management. In drawing on Meyerson and Kolb’s framework for understanding gender in organizations, we highlight how policies are both vital and yet insufficient in and of themselves in revising the dominant discourse around menopause at work. At the same time, we highlight the importance and shortcomings of academic activism within these processes

    On our own terms : the working conditions of internet-based sex workers in the UK

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    The sex industry is increasingly operated through online technologies, whether this is selling services online through webcam or advertising, marketing or organising sex work through the Internet and digital technologies. Using data from a survey of 240 internet-based sex workers (members of the National Ugly Mug reporting scheme in the UK), we discuss the working conditions of this type of work. We look at the basic working patterns, trajectories and everyday experiences of doing sex work via an online medium and the impact this has on the lives of sex workers. For instance, we look at levels of control individuals have over their working conditions, prices, clientele and services sold, and discuss how this is mediated online and placed in relation to job satisfaction. The second key finding is the experience of different forms of crimes individuals are exposed to such as harassment and blackmail via the new technologies. We explore the relationship internet-based sex workers have with the police and discuss how current laws in the UK have detrimental effects in terms of safety and access to justice. These findings are placed in the context of the changing landscape of sex markets as the digital turn determines the nature of the majority of commercial sex encounters. These findings contribute significantly to the populist coercion/choice political debates by demonstrating levels and types of agency and autonomy experienced by some sex workers despite working in a criminalized, precarious and sometimes dangerous context
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