1,960 research outputs found

    Haematalogical investigations in children

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    The haematology laboratory is able to perform a number of tests to help establish the cause of illness in children. The full blood count (FBC, also known as a complete blood count, CBC) is one of the most basic blood tests performed on children attending hospital or a primary care clinic. All doctors should therefore have an understanding of how the test is performed, possible pitfalls, be able to interpret results and know when more specialised testing or advice is required. Other haematological investigations in routine use include coagulation screens, blood film examination, reticulocyte counts and methods for estimation of iron stores and detection of abnormal haemoglobins. This section will focus on these basic tests and simple algorithms for the subsequent investigation and differential diagnosis of the commonest haemato-logical abnormalities encountered in general paediatric practice. The reader is referred to Chapter 15 for an account of the clinical presentation and management of primary haematological disorders in children

    Diffusion-limited aggregation as branched growth

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    I present a first-principles theory of diffusion-limited aggregation in two dimensions. A renormalized mean-field approximation gives the form of the unstable manifold for branch competition, following the method of Halsey and Leibig [Phys. Rev. A {\bf 46}, 7793 (1992)]. This leads to a result for the cluster dimensionality, D \approx 1.66, which is close to numerically obtained values. In addition, the multifractal exponent \tau(3) = D in this theory, in agreement with a proposed `electrostatic' scaling law.Comment: 13 pages, one figure not included (available by request, by ordinary mail), Plain Te

    Granular gravitational collapse and chute flow

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    Inelastic grains in a flow under gravitation tend to collapse into states in which the relative normal velocities of two neighboring grains is zero. If the time scale for this gravitational collapse is shorter than inverse strain rates in the flow, we propose that this collapse will lead to the formation of ``granular eddies", large scale condensed structures of particles moving coherently with one another. The scale of these eddies is determined by the gradient of the strain rate. Applying these concepts to chute flow of granular media, (gravitationally driven flow down inclined planes) we predict the existence of a bulk flow region whose rheology is determined only by flow density. This theory yields the experimental ``Pouliquen flow rule", correlating different chute flows; it also correctly accounts for the different flow regimes observed.Comment: LaTeX2e with epl class, 7 pages, 2 figures, submitted to Europhysics Letter

    High-Dimensional Diffusive Growth

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    We consider a model of aggregation, both diffusion-limited and ballistic, based on the Cayley tree. Growth is from the leaves of the tree towards the root, leading to non-trivial screening and branch competition effects. The model exhibits a phase transition between ballistic and diffusion-controlled growth, with non-trivial corrections to cluster size at the critical point. Even in the ballistic regime, cluster scaling is controlled by extremal statistics due to the branching structure of the Cayley tree; it is the extremal nature of the fluctuations that enables us to solve the model.Comment: 5 pages, 3 figures; reference adde

    Branched Growth with η≈4\eta \approx 4 Walkers

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    Diffusion-limited aggregation has a natural generalization to the "η\eta-models", in which η\eta random walkers must arrive at a point on the cluster surface in order for growth to occur. It has recently been proposed that in spatial dimensionality d=2d=2, there is an upper critical ηc=4\eta_c=4 above which the fractal dimensionality of the clusters is D=1. I compute the first order correction to DD for η<4\eta <4, obtaining D=1+1/2(4−η)D=1+{1/2}(4-\eta). The methods used can also determine multifractal dimensions to first order in 4−η4-\eta.Comment: 6 pages, 1 figur

    Multifractal Dimensions for Branched Growth

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    A recently proposed theory for diffusion-limited aggregation (DLA), which models this system as a random branched growth process, is reviewed. Like DLA, this process is stochastic, and ensemble averaging is needed in order to define multifractal dimensions. In an earlier work [T. C. Halsey and M. Leibig, Phys. Rev. A46, 7793 (1992)], annealed average dimensions were computed for this model. In this paper, we compute the quenched average dimensions, which are expected to apply to typical members of the ensemble. We develop a perturbative expansion for the average of the logarithm of the multifractal partition function; the leading and sub-leading divergent terms in this expansion are then resummed to all orders. The result is that in the limit where the number of particles n -> \infty, the quenched and annealed dimensions are {\it identical}; however, the attainment of this limit requires enormous values of n. At smaller, more realistic values of n, the apparent quenched dimensions differ from the annealed dimensions. We interpret these results to mean that while multifractality as an ensemble property of random branched growth (and hence of DLA) is quite robust, it subtly fails for typical members of the ensemble.Comment: 82 pages, 24 included figures in 16 files, 1 included tabl

    WHO LIVES, WHO DIES, WHO TELLS YOUR STORY: A CASE STUDY OF HAMILTON: AN AMERICAN MUSICAL TO UNDERSTAND THE EFFECT OF ENGAGING THE PAST IN THE CULTURE OF TODAY

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    This thesis is a look into how Alexander Hamilton has been portrayed on stage in the musical Hamilton: An American Musical, written by Lin-Manuel Miranda. The goal of this research is to show that this musical is not history, but rather a commentary on current culture through one of America’s favorite stories (that of the Revolution.) In this show, past figures have been used to discuss the issues of modern America, and that is now being sold as history. This has been discovered through the analysis of primary and secondary sources of the time period, as well as through a listening to and understanding of the show. Through this analysis, it can be seen that anachronism is a real and present danger in the study of history, as modern ideas influence the story being told. While historically based art can be beautiful, it is often shaped into the story writers wish to tell rather than what had occurred

    Effect of weak disorder in the Fully Frustrated XY model

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    The critical behaviour of the Fully Frustrated XY model in presence of weak positional disorder is studied in a square lattice by Monte Carlo methods. The critical exponent associated to the divergence of the chiral correlation length is found to be equal to 1.7 already at very small values of disorder. Furthermore the helicity modulus jump is found larger than the universal value expected in the XY model.Comment: 8 pages, 4 figures (revtex
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