Experimental determination of the particle motions associated with the low order acoustic modes in enclosures

A procedure for experimentally determining, in terms of the particle motions, the shapes of the low order acoustic modes in enclosures is described. The procedure is based on finding differentiable functions which approximate the shape functions of the low order acoustic modes when these modes are defined in terms of the acoustic pressure. The differentiable approximating functions are formed from polynomials which are fitted by a least squares procedure to experimentally determined values which define the shapes of the low order acoustic modes in terms of the acoustic pressure. These experimentally determined values are found by a conventional technique in which the transfer functions, which relate the acoustic pressures at an array of points in the enclosure to the volume velocity of a fixed point source, are measured. The gradient of the function which approximates the shape of a particular mode in terms of the acoustic pressure is evaluated to give the mode shape in terms of the particle motion. The procedure was tested by using it to experimentally determine the shapes of the low order acoustic modes in a small rectangular enclosure

Split-Stirling-cycle displacer linear-electric drive

The retrofit of a 1/4-W split-Stirling cooler with a linear driven on the displacer was achieved and its performance characterized. The objective of this work was to demonstrate that a small linear motor could be designed to meet the existing envelope specifications of the cooler and that an electric linear drive on the displacer could improve the cooler's reliability and performance. The paper describes the characteristics of this motor and presents cooler test results

Colorectal Cancer Through Simulation and Experiment

Colorectal cancer has continued to generate a huge amount of research interest over several decades, forming a canonical example of tumourigenesis since its use in Fearon and Vogelstein’s linear model of genetic mutation. Over time, the field has witnessed a transition from solely experimental work to the inclusion of mathematical biology and computer-based modelling. The fusion of these disciplines has the potential to provide valuable insights into oncologic processes, but also presents the challenge of uniting many diverse perspectives. Furthermore, the cancer cell phenotype defined by the ‘Hallmarks of Cancer’ has been extended in recent times and provides an excellent basis for future research. We present a timely summary of the literature relating to colorectal cancer, addressing the traditional experimental findings, summarising the key mathematical and computational approaches, and emphasising the role of the Hallmarks in current and future developments. We conclude with a discussion of interdisciplinary work, outlining areas of experimental interest which would benefit from the insight that mathematical and computational modelling can provide

Object-Oriented Paradigms for Modelling Vascular\ud Tumour Growth: a Case Study

Motivated by a family of related hybrid multiscale models, we have built an object-oriented framework for developing and implementing multiscale models of vascular tumour growth. The models are implemented in our framework as a case study to highlight how object-oriented programming techniques and good object-oriented design may be used effectively to develop hybrid multiscale models of vascular tumour growth. The intention is that this paper will serve as a useful reference for researchers modelling complex biological systems and that these researchers will employ some of the techniques presented herein in their own projects

Effect of feeding fermentable fibrerich feedstuffs on meat quality with emphasis on chemical and sensory boar taint in entire male and female pigs

Skatole, androstenone and other compounds such as indole cause boar taint in entire male pork. However, female pigs also produce skatole and indole. The purpose of this experiment was to minimise boar taint and increase overall impression of sensory quality by feeding entire male and female pigs with fibrerich feedstuffs. The pigs have been fed three organic diets for either 1 or 2 weeks prior to slaughter of which two diets contained different fermentable fibre-rich feedstuffs – 10–13.3% dried chicory roots or 25% blue lupines. These two treatments were compared with pigs fed with an organic control diet for either 1 or 2 weeks prior to slaughter. Lupines significantly reduced skatole in blood and backfat for both genders after 1 week. Moreover, lupines showed negative impact on growth rate and feed conversion whilst chicory showed no significant differences in this respect. However, the indole concentration was significantly lower in chicory than lupine fed pigs. From a sensory perspective, chicory and lupine feeding reduced boar taint since odour and flavour of manure related to skatole and urine associated to androstenone were minimised. The level of boar taint in the entire male pigs was most effectively reduced after 14 days by both fibre-rich feeds while lupine had the largest influence on ‘‘boar” taint reduction in female pigs

Evaluation of Seismic Stability of Foundation Soils Under Revelstoke Earthfill Dam

The stability of the fine sands underlying the shells of the Revelstoke earthfill dam under earthquake shaking is discussed. The evaluation of liquefaction potential of the deposit was made from the field standard penetration resistance of the material. The dynamic analysis, made by a one-dimensional equivalent visco-elastic method, indicated that the sand under both the upstream and downstream shells had adequate liquefaction resistance and could be left in place. Adequate drainage of downstream fine sands was provided to further reduce its liquefaction potential

Summary care record early adopter programme: an independent evaluation by University College London.

Benefits The main potential benefit of the SCR is considered to be in emergency and unscheduled care settings, especially for people who are unconscious, confused, unsure of their medical details, or unable to communicate effectively in English. Other benefits may include improved efficiency of care and avoidance of hospital admission, but it is too early for potential benefits to be verified or quantified. Progress As of end April 2008, the SCR of 153,188 patients in the first two Early Adopter sites (Bolton and Bury) had been created. A total of 614,052 patients in four Early Adopter sites had been sent a letter informing them of the programme and their choices for opting out of having a SCR. Staff attitudes and usage The evaluation found that many NHS staff in Early Adopter sites (which had been selected partly for their keenness to innovate in ICT) were enthusiastic about the SCR and keen to see it up and running, but a significant minority of GPs had chosen not to participate in the programme and others had deferred participation until data quality improvement work was completed. Whilst 80 per cent of patients interviewed were either positive about the idea of having a SCR or ?did not mind?, others were strongly opposed ?on principle?. Staff who had attempted to use the SCR when caring for patients felt that the current version was technically immature (describing it as ?clunky? and ?complicated?), and were looking forward to a more definitive version of the technology. A comparable technology (the Emergency Care Summary) introduced in Scotland two years ago is now working well, and over a million records have been accessed in emergency and out-of-hours care. Patient attitudes and awareness Having a SCR is optional (people may opt out if they wish, though fewer than one per cent of people in Early Adopter sites have done so) and technical security is said to be high via a system of password protection and strict access controls. Nevertheless, the evaluation showed that recent stories about data loss by government and NHS organisations had raised concerns amongst both staff and patients that human fallibility could potentially jeopardise the operational security of the system. Despite an extensive information programme to inform the public in Early Adopter sites about the SCR, many patients interviewed by the UCL team were not aware of the programme at all. This raises important questions about the ethics of an ?implied consent? model for creating the SCR. The evaluation recommended that the developers of the SCR should consider a model in which the patient is asked for ?consent to view? whenever a member of staff wishes to access their record. Not a single patient interviewed in the evaluation was confident that the SCR would be 100 per cent secure, but they were philosophical about the risks of security breaches. Typically, people said that the potential benefit of a doctor having access to key medical details in an emergency outweighed the small but real risk of data loss due to human or technical error. Even patients whose medical record contained potentially sensitive data such as mental health problems, HIV or drug use were often (though not always) keen to have a SCR and generally trusted NHS staff to treat sensitive data appropriately. However, they and many other NHS patients wanted to be able to control which staff members were allowed to access their record at the point of care. Some doctors, nurses and receptionists, it seems, are trusted to view a person?s SCR, whereas others are not, and this is a decision which patients would like to make in real time

Concentric left ventricular remodeling and aortic stiffness: A comparison of obesity and hypertension

Licensed under the Creative Commons Attribution Non-Commercial No Derivatives Licens

Modelling spatially regulated B-catenin dynamics & invasion in intestinal crypts

Experimental data (e.g., genetic lineage and cell population studies) on intestinal crypts reveal that regulatory features of crypt behavior, such as control via morphogen gradients, are remarkably well conserved among numerous organisms (e.g., from mouse and rat to human) and throughout the different regions of the small and large intestines. In this article, we construct a partial differential equation model of a single colonic crypt that describes the spatial distribution of Wnt pathway proteins along the crypt axis. The novelty of our continuum model is that it is based upon assumptions that can be directly related to processes at the cellular and subcellular scales. We use the model to predict how the distributions of Wnt pathway proteins are affected by mutations. The model is then extended to investigate how mutant cell populations can invade neighboring crypts. The model simulations suggest that cell crowding caused by increased proliferation and decreased cell loss may be sufficient for a mutant cell population to colonize a neighboring healthy crypt