6,924 research outputs found
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An Inverse Geometry Problem for the Localization of Skin Tumours by Thermal Analysis
In this paper, the Dual Reciprocity Method (DRM) is coupled to a Genetic Algorithm (GA) in an inverse procedure through which the size and location of a skin tumour may be obtained from temperature measurements at the skin surface. The GA is an evolutionary process which does not require the calculation of sensitivities, search directions or the definition of initial guesses. The DRM in this case requires no internal nodes. It is also shown that the DRM approximation function used is not an important factor for the problem considered here. Results are presented for tumours of different sizes and positions in relation to the skin surface
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A coupled dual reciprocity BEM/Genetic algorithm for identification of blood perfusion parameters
The paper presents an inverse analysis procedure based on a coupled numerical formulation through which the coefficients describing non-linear thermal properties of blood perfusion may be identified. The numerical technique involves a combination of the Dual Reciprocity Boundary Element Method and a Genetic Algorithm for the solution of the Pennes bioheat equation. Both linear and quadratic temperature-dependent variations are considered for the blood perfusion
Hot Routes: Developing a New Technique for the Spatial Analysis of Crime
The use of hotspot mapping techniques such as KDE to represent the geographical spread of linear events can be problematic. Network-constrained data (for example transport-related crime) require a different approach to visualize concentration. We propose a methodology called Hot Routes, which measures the risk distribution of crime along a linear network by calculating the rate of crimes per section of road. This method has been designed for everyday crime analysts, and requires only a Geographical Information System (GIS), and suitable data to calculate. A demonstration is provided using crime data collected from London bus routes
Intervening in ageing to prevent the diseases of ageing
Increases in human lifespan worldwide have revealed that advancing age is the predominant risk factor for major life-threatening diseases. Recent work has shown that ageing in diverse animals, including humans, is malleable to specific types of genetic mutation, diet, and drugs that can extend lifespan and improve health during ageing. These findings point to the prospect of broad-spectrum preventive medicine for the diseases of ageing based on intervention in relevant aspects of the ageing process itself
Stress, Theory of Mind and emotional and behavioural difficulties in children.
This review focuses on the nature of individual differences in Theory of Mind (ToM) and examines evidence concerning the links between ToM and children's emotional and behavioural problems. An introduction to ToM is given, followed by a brief synopsis of what is known about the influences on individual differences in ToM. The review considers ToM in relation to peer rejection, attention and behavioural difficulties, bullying and emotional difficulties. Research in these areas is in its infancy and the review describes the difficulties intrinsic to this type of research (for example, measuring ToM) as well as drawing the reader to the importance and potential implications of ToM research in child development and the development of psychological difficulties. Ideas for further research are proposed
Longevity in response to lowered insulin signalling requires glycine N- methyltransferase-dependent spermidine production
Reduced insulin/IGF signaling (IIS) extends lifespan in multiple organisms. Different
processes in different tissues mediate this lifespan extension, with a set of interplays
that remain unclear. We here show that, in Drosophila, reduced IIS activity modulates
methionine metabolism, through tissue-specific regulation of glycine Nmethyltransferase (Gnmt), and that this regulation is required for full IIS-mediated
longevity. Furthermore, fat-body-specific expression of Gnmt was sufficient to extend
lifespan. Targeted metabolomics showed that reducing IIS activity led to a Gnmtdependent increase in spermidine levels. We also show that both spermidine
treatment and reduced IIS activity are sufficient to extend the lifespan of Drosophila,
but only in the presence of Gnmt. This extension of lifespan was associated with
increased levels of autophagy. Finally, we found that increased expression of Gnmt
occurs in the liver of liver-specific IRS1 KO mice, and is thus an evolutionary
conserved response to reduced IIS. The discovery of Gnmt and spermidine as
tissue-specific modulators of IIS-mediated longevity may aid in developing future
therapeutic treatments to ameliorate ageing and prevent disease
Quantification of food intake in Drosophila
Measurement of food intake in the fruit fly Drosophila melanogaster is often necessary for studies of behaviour, nutrition and drug administration. There is no reliable and agreed method for measuring food intake of flies in undisturbed, steady state, and normal culture conditions. We report such a method, based on measurement of feeding frequency by proboscis-extension, validated by short-term measurements of food dye intake. We used the method to demonstrate that (a) female flies feed more frequently than males, (b) flies feed more often when housed in larger groups and (c) fly feeding varies at different times of the day. We also show that alterations in food intake are not induced by dietary restriction or by a null mutation of the fly insulin receptor substrate chico. In contrast, mutation of takeout increases food intake by increasing feeding frequency while mutation of ovoD increases food intake by increasing the volume of food consumed per proboscis-extension. This approach provides a practical and reliable method for quantification of food intake in Drosophila under normal, undisturbed culture conditions
Alien Registration- Partridge, Alice L. (Gardiner, Kennebec County)
https://digitalmaine.com/alien_docs/29068/thumbnail.jp
Effect of a standardised dietary restriction protocol on multiple laboratory strains of Drosophila melanogaster
Background:
Outcomes of lifespan studies in model organisms are particularly susceptible to variations in technical procedures. This is especially true of dietary restriction, which is implemented in many different ways among laboratories.
Principal Findings:
In this study, we have examined the effect of laboratory stock maintenance, genotype differences and microbial infection on the ability of dietary restriction (DR) to extend life in the fruit fly Drosophila melanogaster. None of these factors block the DR effect.
Conclusions:
These data lend support to the idea that nutrient restriction genuinely extends lifespan in flies, and that any mechanistic discoveries made with this model are of potential relevance to the determinants of lifespan in other organisms
The margin of safety of a left double-lumen tracheobronchial tube depends on the length of the bronchial cuff and tip
Publisher's copy made available with the permission of the publisher Β© Australian Society of AnaesthetistsThe left tracheobronchial double-lumen tube is the commonest device to separate the left and right lungs for differential ventilation. With the appropriate tube, the left bronchial cuff is positioned in the bronchus so that the cuff is beyond the carina but the tip of the tube does not occlude the aperture of the left upper lobe bronchus. The difference between the length of the left main bronchus and the length of the cuff and tip of the bronchial segment of the tube has been termed 'the margin of safety' by Benumof. If the length of the cuff plus the tip exceeds that of the left main bronchus, there will be occlusion of the left upper lobe bronchus. The bronchial cuff and bronchial tip lengths were measured on two hundred and twenty left tracheobronchial (double-lumen) tubes from four manufacturers. The largest cuffβtip length was 40 mm with a Portex 41Fr tube but some 41Fr tubes from all manufacturers had cuffβtip lengths of 33 mm or greater which exceed the length of the shortest left main bronchus measured by Benumof. There was also a marked variation in cuffβtip lengths of the same size tube from the same manufacturer. The largest variation was 18 mm for the Portex 41 but substantial variation of 8 mm or more was found in at least one French size of all manufacturers. Users must be aware that significant cuffβtip length variation occurs and match the selected tube to the patient to ensure an adequate margin of safety.L. Partridge, W. J. Russellhttp://www.aaic.net.au/Article.asp?D=200600
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