810 research outputs found
Efficiency vs. Meaningful Work: A Critical Survey of Historical and Contemporary Debates
This paper considers the trade-off between the demand for efficiency and the demand for meaningful work. It asks whether this trade-off should be treated as inevitable or potentially resolvable, at least under reformed conditions. It compares historical and contemporary debates where the trade-off features. It focuses initially on Adam Smithās account of the division of labour in which less meaningful work is assumed to be the necessary price of higher efficiency. It then examines Karl Marxās analysis of work, showing how it differs from that of Smith. Marx addressed the scope for achieving meaningful work whilst supporting needs fulfilment in a future socialist society. In addition, the paper looks at how the ideas of Smith and Marx relate to modern discussions that focus on the capacity of new digital technologies to lighten work. Finally, it draws lessons for welfare economics on how meaningful work and efficiency might be reconciled
Hypomagnesaemia in cystic fibrosis patients referred for lung transplant assessment
AbstractBackgroundHypomagnesaemia in patients with cystic fibrosis (CF) is underrecognized although the true incidence is unknown. Many patients are asymptomatic, although severe deficiency may be associated with muscle weakness, cramps and tetany. Hypomagnesaemia may be a risk factor for post-transplant complications including convulsions, which may be exacerbated by the use of calcineurin inhibitors. The aims of the present study were to describe serum magnesium levels and to investigate the relationship between magnesium levels and age, and renal function measurements in patients with CF referred to a transplant centre for lung transplant assessment.MethodsWe reviewed the data of all 106 CF patients referred for transplant assessment from January 1995 to December 2003. Demographic and biochemical data were recorded and the explanatory variables were subjected to univariate analysis and linear regression analysis.ResultsMean serum magnesium level was 0.75Ā mmol/L (range 0.46ā1.03, normal range 0.74ā1.1). 57% of patients had hypomagnesaemia. Serum magnesium levels were not associated with age, serum creatinine or GFR.ConclusionsHypomagnesaemia is a common finding in patients with CF referred for lung transplant assessment. Serum magnesium levels should be monitored in all CF patients being referred for lung transplant irrespective of the results of other renal function tests
Neutral Plasma Oscillations at Zero Temperature
We use cold plasma theory to calculate the response of an ultracold neutral
plasma to an applied rf field. The free oscillation of the system has a
continuous spectrum and an associated damped quasimode. We show that this
quasimode dominates the driven response. We use this model to simulate plasma
oscillations in an expanding ultracold neutral plasma, providing insights into
the assumptions used to interpret experimental data [Phys. Rev. Lett. 85, 318
(2000)].Comment: 4.3 pages, including 3 figure
Machine learning classification of OARSI-scored human articular cartilage using magnetic resonance imaging
SummaryObjectiveThe purpose of this study is to evaluate the ability of machine learning to discriminate between magnetic resonance images (MRI) of normal and pathological human articular cartilage obtained under standard clinical conditions.MethodAn approach to MRI classification of cartilage degradation is proposed using pattern recognition and multivariable regression in which image features from MRIs of histologically scored human articular cartilage plugs were computed using weighted neighbor distance using compound hierarchy of algorithms representing morphology (WND-CHRM). The WND-CHRM method was first applied to several clinically available MRI scan types to perform binary classification of normal and osteoarthritic osteochondral plugs based on the Osteoarthritis Research Society International (OARSI) histological system. In addition, the image features computed from WND-CHRM were used to develop a multiple linear least-squares regression model for classification and prediction of an OARSI score for each cartilage plug.ResultsThe binary classification of normal and osteoarthritic plugs yielded results of limited quality with accuracies between 36% and 70%. However, multiple linear least-squares regression successfully predicted OARSI scores and classified plugs with accuracies as high as 86%. The present results improve upon the previously-reported accuracy of classification using average MRI signal intensities and parameter values.ConclusionMRI features detected by WND-CHRM reflect cartilage degradation status as assessed by OARSI histologic grading. WND-CHRM is therefore of potential use in the clinical detection and grading of osteoarthritis
Parsimonious modeling of skeletal muscle perfusion: connecting the stretched exponential and fractional Fickian diffusion
Purpose To develop an anomalous (non-Gaussian) diffusion model for characterizing skeletal muscle perfusion using multi-b-value DWI.Theory and methods Fick's first law was extended for describing tissue perfusion as anomalous superdiffusion, which is non-Gaussian diffusion exhibiting greater particle spread than that of the Gaussian case. This was accomplished using a space-fractional derivative that gives rise to a power-law relationship between mean squared displacement and time, and produces a stretched exponential signal decay as a function of b-value. Numerical simulations were used to estimate parameter errors under in vivo conditions, and examine the effect of limited SNR and residual fat signal. Stretched exponential DWI parameters, alpha and D, were measured in thigh muscles of 4 healthy volunteers at rest and following in-magnet exercise. These parameters were related to a stable distribution of jump-length probabilities and used to estimate microvascular volume fractions.Results Numerical simulations showed low dispersion in parameter estimates within 1.5% and 1%, and bias errors within 3% and 10%, for alpha and D, respectively. Superdiffusion was observed in resting muscle, and to a greater degree following exercise. Resting microvascular volume fraction was between 0.0067 and 0.0139 and increased between 2.2-fold and 4.7-fold following exercise.Conclusions This model captures superdiffusive molecular motions consistent with perfusion, using a parsimonious representation of the DWI signal, providing approximations of microvascular volume fraction comparable with histological estimates. This signal model demonstrates low parameter-estimation errors, and therefore holds potential for a wide range of applications in skeletal muscle and elsewhere in the body.Radiolog
Elastic Chain in a Random Potential: Simulation of the Displacement Function and Relaxation
We simulate the low temperature behaviour of an elastic chain in a random
potential where the displacements are confined to the {\it longitudinal}
direction ( parallel to ) as in a one dimensional charge density
wave--type problem. We calculate the displacement correlation function and the size dependent average square displacement
. We find that with
at short distances and at intermediate
distances. We cannot resolve the asymptotic long distance dependence of
upon . For the system sizes considered we find with . The exponent is in agreement
with the Random Manifold exponent obtained from replica calculations and the
exponent is consistent with an exact solution for the chain
with {\it transverse} displacements ( perpendicular to ).The
distribution of nearest distances between pinning wells and chain-particles is
found to develop forbidden regions.Comment: 19 pages of LaTex, 6 postscript figures available on request,
submitted to Journal of Physics A, MAJOR CHANGE
Theorising Disability: Beyond Common Sense
This article seeks to introduce the topic of disability to political theory via a discussion of some of the literature produced by disability theorists. The author argues that these more radical approaches conceptualise disability in ways that conflict with ācommon-senseā notions of disability that tend to underpin political theoretical considerations of the topic. Furthermore, the author suggests that these more radical conceptualisations have profound implications for current debates on social justice, equality and citizenship that highlight the extent to which these notions are also currently underpinned by ācommon-senseā notions of ānormalityā
Accessing elite nurses for research: reflections on the theoretical and practical issues of telephone interviewing
Elite groups are interesting as they frequently are powerful (in terms of position, knowledge and influence) and enjoy considerable authority. It is important, therefore, to involve them in research concerned with understanding social contexts and processes. This is particularly pertinent in healthcare, where considerable strategic development and change are features of everyday practice that may be guided or perceived as being guided, by elites.
This paper evolved from a study investigating the availability and role of nurses whose remit involved leading nursing research and development within acute NHS Trusts in two health regions in Southern England. The study design included telephone interviews with Directors of Nursing Services during which time the researchers engaged in a reflective analysis of their experiences of conducting research with an `elite' group. Important issues identified were the role of gatekeepers, engagement with elites and the use of the telephone interview method in this context. The paper examines these issues and makes a case for involving executive nurses in further research. The paper also offers strategies to help researchers design and implement telephone interview studies successfully to maximise access to the views and experiences of `hard to reach groups', such as elites, while minimising the associated disruption
Pogodnosti i izazovi deterministiÄkog referentnog modela radijskog kanala
The paper introduces a new paradigm for reference channel models. Current reference channel models are designed as platforms that generate radio channels for testing using random values for their parameters. These parameters follow some pre-established distribution based on process called parameterization, i.e. statistical processing of previous real measurements or accurate ray tracing simulations. The paper argues that random generated channels give either no new insight or even delusive information and should be replaced with the initial set of radio channels that was used for parameterization. Therefore a deterministic reference channel model, as an emulator of previously recorded real radio channels, is proposed and its potential elaborated.U radu se uvodi nova paradigma za referentni model radijskog kanala. PostojeÄi referentni modeli radijskog kanala dizajnirani su kao platforma koja generira radio kanale za testiranje pomoÄu sluÄajnih vrijednosti za svoje parametre. Ovi parametri prate neke unaprijed utvrÄene raspodjele koje potjeÄu iz procesa parametrizacije, odnosno statistiÄke obrade prethodnih mjerenja ili toÄnih simulacija metodom slijeÄenja zrake. U radu se tvrdi da sluÄajno generirani kanali ili ne daju nove uvide ili Äak daju obmanjujuÄe informacije i valja ih zamijeniti s poÄetnim skupom radijskih kanala koji je koriÅ”ten za parametrizaciju. Stoga je predložen deterministiÄki referentni model radijskog kanala, kao emulator prethodno snimljenih stvarnih radio kanala, te je njegov potencijal razraÄen
Snow petrel stomach-oil deposits as a new biological archive of Antarctic sea ice
Where snow petrels forage is predominantly a function of sea ice. They spit stomach oil in defence, and accumulated deposits at nesting sites are providing new opportunities to reconstruct their diet, and, in turn, the sea-ice environment over past millennia
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