Non-continuous and variable rate processes: Optimisation for energy use

The need to develop new and improved ways of reducing energy use and increasing energy intensity in industrial processes is currently a major issue in New Zealand. Little attention has been given to optimisation of non-continuous processes in the past, due to their complexity, yet they remain an essential and often energy intensive component of many industrial sites. Novel models based on pinch analysis that aid in minimising utility usage have been constructed here through the adaptation of proven continuous techniques. The knowledge has been integrated into a user friendly software package, and allows the optimisation of processes under variable operating rates and batch conditions. An example problem demonstrates the improvements in energy use that can be gained when using these techniques to analyse non-continuous data. A comparison with results achieved using a pseudo-continuous method show that the method described can provide simultaneous reductions in capital and operating costs

Condensation of microturbulence-generated shear flows into global modes

In full flux-surface computer studies of tokamak edge turbulence, a spectrum of shear flows is found to control the turbulence level and not just the conventional (0,0)-mode flows. Flux tube domains too small for the large poloidal scale lengths of the continuous spectrum tend to overestimate the flows, and thus underestimate the transport. It is shown analytically and numerically that under certain conditions dominant (0,0)-mode flows independent of the domain size develop, essentially through Bose-Einstein condensation of the shear flows.Comment: 5 pages, 4 figure

Apraxia and motor dysfunction in corticobasal syndrome

Background: Corticobasal syndrome (CBS) is characterized by multifaceted motor system dysfunction and cognitive disturbance; distinctive clinical features include limb apraxia and visuospatial dysfunction. Transcranial magnetic stimulation (TMS) has been used to study motor system dysfunction in CBS, but the relationship of TMS parameters to clinical features has not been studied. The present study explored several hypotheses; firstly, that limb apraxia may be partly due to visuospatial impairment in CBS. Secondly, that motor system dysfunction can be demonstrated in CBS, using threshold-tracking TMS, and is linked to limb apraxia. Finally, that atrophy of the primary motor cortex, studied using voxel-based morphometry analysis (VBM), is associated with motor system dysfunction and limb apraxia in CBS.   Methods: Imitation of meaningful and meaningless hand gestures was graded to assess limb apraxia, while cognitive performance was assessed using the Addenbrooke's Cognitive Examination - Revised (ACE-R), with particular emphasis placed on the visuospatial subtask. Patients underwent TMS, to assess cortical function, and VBM.   Results: In total, 17 patients with CBS (7 male, 10 female; mean age 64.4+/2 6.6 years) were studied and compared to 17 matched control subjects. Of the CBS patients, 23.5% had a relatively inexcitable motor cortex, with evidence of cortical dysfunction in the remaining 76.5% patients. Reduced resting motor threshold, and visuospatial performance, correlated with limb apraxia. Patients with a resting motor threshold <50% performed significantly worse on the visuospatial sub-task of the ACE-R than other CBS patients. Cortical function correlated with atrophy of the primary and pre-motor cortices, and the thalamus, while apraxia correlated with atrophy of the pre-motor and parietal cortices.   Conclusions: Cortical dysfunction appears to underlie the core clinical features of CBS, and is associated with atrophy of the primary motor and pre-motor cortices, as well as the thalamus, while apraxia correlates with pre-motor and parietal atrophy

Investigating low-velocity fluid flow in tumours using convection-MRI

Several distinct fluid flow phenemena occur in solid tumours, including intravascular blood flow and interstitial convection. To probe low-velocity flow in tumors resulting from raised interstitial fluid pressure, we have developed a novel magnetic resonance imaging (MRI) technique named convection-MRI. It uses a phase-contrast acquisition with a dual-inversion vascular nulling preparation to separate intra- and extra-vascular flow. Here, we report the results of experiments in flow phantoms, numerical simulations and tumor xenograft models to investigate the technical feasibility of convection-MRI. We report a good correlation between estimates of effective fluid pressure from convection-MRI with gold-standard, invasive measurements of interstitial fluid pressure in mouse models of human colorectal carcinoma and show that convection-MRI can provide insights into the growth and response to vascular-targeting therapy in colorectal cancers

Uridine Metabolism in the Goldfish Retina During Optic Nerve Regeneration: Whole Retina Studies

Accumulation of radioactivity from [ 3 H]uridine in incubations of whole goldfish retinas is increased in the ipsilateral retina during a period of regeneration that follows unilateral optic nerve crush. Brief incubations to investigate the nature of enhanced labeling of the acid-soluble fraction showed a peak uptake 4 days following crush, with a gradual decrease to control levels by 21 days following crush. That nucleoside uptake may not mediate the effect is supported by the observation that the rate of uptake of 5′-deoxyadenosine, a nonmetabolizable nucleoside analog, is the same in post-crush (PC) and normal (N) retinal incubations. Following brief incubations of PC and N retinas with [ 3 H]uridine, there is enhanced labeling in PC retinas relative to N retinas of recovered UMP, UDP, UTP, and uridine nucleotide sugars, whereas recovery of labeled uridine itself is slightly decreased. The results suggest that the increased accumulation of radioactivity in PC retinas following incubation with uridine reflects an increase in the activities of retinal uridine kinase and uridine nucleotide kinases.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65630/1/j.1471-4159.1981.tb01713.x.pd

Checkpoints are blind to replication restart and recombination intermediates that result in gross chromosomal rearrangements

Replication fork inactivation can be overcome by homologous recombination, but this can cause gross chromosomal rearrangements that subsequently missegregate at mitosis, driving further chromosome instability. It is unclear when the chromosome rearrangements are generated and whether individual replication problems or the resulting recombination intermediates delay the cell cycle. Here we have investigated checkpoint activation during HR-dependent replication restart using a site-specific replication fork-arrest system. Analysis during a single cell cycle shows that HR-dependent replication intermediates arise in S phase, shortly after replication arrest, and are resolved into acentric and dicentric chromosomes in G2. Despite this, cells progress into mitosis without delay. Neither the DNA damage nor the intra-S phase checkpoints are activated in the first cell cycle, demonstrating that these checkpoints are blind to replication and recombination intermediates as well as to rearranged chromosomes. The dicentrics form anaphase bridges that subsequently break, inducing checkpoint activation in the second cell cycle

Convergence calls: multimedia storytelling at British news websites

This article uses qualitative interviews with senior editors and managers from a selection of the UK's national online news providers to describe and analyse their current experimentation with multimedia and video storytelling. The results show that, in a period of declining newspaper readership and TV news viewing, editors are keen to embrace new technologies, which are seen as being part of the future of news. At the same time, text is still reported to be the cornerstone for news websites, leading to changes in the grammar and function of news video when used online. The economic rationale for convergence is examined and the article investigates the partnerships sites have entered into in order to be able to serve their audience with video content. In-house video is complementing syndicated content, and the authors examine the resulting developments in newsroom training and recruitment practices. The article provides journalism and interactive media scholars with case studies on the changes taking place in newsrooms as a result of the shift towards multimedia, multiplatform news consumption

Quantum Quenches in Extended Systems

We study in general the time-evolution of correlation functions in a extended quantum system after the quench of a parameter in the hamiltonian. We show that correlation functions in d dimensions can be extracted using methods of boundary critical phenomena in d+1 dimensions. For d=1 this allows to use the powerful tools of conformal field theory in the case of critical evolution. Several results are obtained in generic dimension in the gaussian (mean-field) approximation. These predictions are checked against the real-time evolution of some solvable models that allows also to understand which features are valid beyond the critical evolution. All our findings may be explained in terms of a picture generally valid, whereby quasiparticles, entangled over regions of the order of the correlation length in the initial state, then propagate with a finite speed through the system. Furthermore we show that the long-time results can be interpreted in terms of a generalized Gibbs ensemble. We discuss some open questions and possible future developments.Comment: 24 Pages, 4 figure

The New ‘Hidden Abode’: Reflections on Value and Labour in the New Economy

In a pivotal section of Capital, volume 1, Marx (1976: 279) notes that, in order to understand the capitalist production of value, we must descend into the ‘hidden abode of production’: the site of the labour process conducted within an employment relationship. In this paper we argue that by remaining wedded to an analysis of labour that is confined to the employment relationship, Labour Process Theory (LPT) has missed a fundamental shift in the location of value production in contemporary capitalism. We examine this shift through the work of Autonomist Marxists like Hardt and Negri, Lazaratto and Arvidsson, who offer theoretical leverage to prize open a new ‘hidden abode’ outside employment, for example in the ‘production of organization’ and in consumption. Although they can open up this new ‘hidden abode’, without LPT's fine-grained analysis of control/resistance, indeterminacy and structured antagonism, these theorists risk succumbing to empirically naive claims about the ‘new economy’. Through developing an expanded conception of a ‘new hidden abode’ of production, the paper demarcates an analytical space in which both LPT and Autonomist Marxism can expand and develop their understanding of labour and value production in today's economy. </jats:p