The CRASH trial: the first large-scale, randomised, controlled trial in head injury.

The global epidemic of head injuries is just beginning. Many are caused by road traffic crashes. It is estimated that, by 2020, road traffic crashes will have moved from its present position of ninth to third in the world disease burden ranking, as measured in disability adjusted life years. In developing countries, it will have moved to second. The Corticosteroid Randomisation After Significant Head Injury (CRASH) trial is a large-scale, randomised, controlled trial, among adults with head injury and impaired consciousness, of the effects of a short-term infusion of corticosteroids on death and on neurological disability. Following a successful pilot phase, which included over 1000 randomised participants, the main phase of the trial is now underway. Over the next 5 years, the trial aims to recruit a total of 20,000 patients. Such large numbers will only be possible if hundreds of doctors and nurses can collaborate in emergency departments all over the world. The trial is currently recruiting, and new collaborators are welcome to join the trial (see www.crash.lshtm.ac.uk)

Fine asymptotics for the consistent maximal displacement of branching Brownian motion

It is well-known that the maximal particle in a branching Brownian motion sits near $\sqrt2 t - \frac{3}{2\sqrt2}\log t$ at time $t$. One may then ask about the paths of particles near the frontier: how close can they stay to this critical curve? Two different approaches to this question have been developed. We improve upon the best-known bounds in each case, revealing new qualitative features including marked differences between the two approaches.Comment: 25 pages; corrected several mistake

Almost sure asymptotics for the random binary search tree

We consider a (random permutation model) binary search tree with n nodes and give asymptotics on the loglog scale for the height H_n and saturation level h_n of the tree as n\to\infty, both almost surely and in probability. We then consider the number F_n of particles at level H_n at time n, and show that F_n is unbounded almost surely.Comment: 12 pages, 2 figure

Timing and volume of fluid administration for patients with bleeding

Original article can be found at: http://www3.interscience.wiley.com Copyright John Wiley & Sons. ‘This review is published as a Cochrane Review in the Cochrane Database of Systematic Reviews 2003, Issue 3. Cochrane Reviews are regularly updated as new evidence emerges and in response to comments and criticisms, and the Cochrane Database of Systematic Reviews should be consulted for the most recent version of the Review.’ Kwan, I. , Bunn, F. and Roberts, I. 'Timing and volume of fluid administration for patients with bleeding.' Cochrane Database Systematic Reviews 2003, (3) CD002245. DOI: 10.1002/14651858.CD002245 http://dx.doi.org/10.1002/14651858.CD002245Background: Treatment of haemorrhagic shock involves maintaining blood pressure and tissue perfusion until bleeding is controlled. Different resuscitation strategies have been used to maintain the blood pressure in trauma patients until bleeding is controlled. However, while maintaining blood pressure may prevent shock, it may worsen bleeding. Objectives: To assess the effects of early versus delayed, and larger versus smaller volume of fluid administration in trauma patients with bleeding. Search strategy: We searched the CENTRAL (The Cochrane Library 2008, Issue 4), the Cochrane Injuries Group's Specialised Register (searched October 2008), MEDLINE (to October 2008), EMBASE (to October 2008), the National Research Register (in Current controlled trials.gov; searched October 2008) and the Science Citation Index (to October 2008). We checked reference lists of identified articles and contacted authors and experts in the field. Selection criteria: Randomised trials of the timing and volume of intravenous fluid administration in trauma patients with bleeding. Trials in which different types of intravenous fluid were compared were excluded. Data collection and analysis: Two authors independently extracted data and assessed trial quality. Main results: We did not combine the results quantitatively because the interventions and patient populations were so diverse. Early versus delayed fluid administration Three trials reported mortality and two coagulation data. In the first trial (n=598) relative risk (RR) for death with early fluid administration was 1.26 (95% confidence interval of 1.00−1.58). The weighted mean differences (WMD) for prothrombin time and partial thromboplastin time were 2.7 (95% CI 0.9−4.5) and 4.3 (95% CI 1.74−6.9) seconds respectively. In the second trial (n=50) RR for death with early blood transfusion was 5.4 (95% CI 0.3−107.1). The WMD for partial thromboplastin time was 7.0 (95% CI 6.0−8.0) seconds. In the third trial (n=1309) RR for death with early fluid administration was 1.06 (95% CI 0.77−1.47). Larger versus smaller volume of fluid administration Three trials reported mortality and one coagulation data. In the first trial (n=36) RR for death with a larger volume of fluid resuscitation was 0.80 (95% CI 0.28−22.29). Prothrombin time and partial thromboplastin time were 14.8 and 47.3 seconds in those who received a larger volume of fluid, as compared to 13.9 and 35.1 seconds in the comparison group. In the second trial (n=110) RR for death with a high systolic blood pressure resuscitation target (100mmHg) maintained with a larger volume of fluid, as compared to low systolic blood pressure resuscitation target (70mmHg) maintained with a smaller volume of fluid was 1.00 (95% CI 0.26−3.81). In the third trial (n=25) there were no deaths. Authors' conclusions: We found no evidence from randomised controlled trials for or against early or larger volume of intravenous fluid administration in uncontrolled haemorrhage. There is continuing uncertainty about the best fluid administration strategy in bleeding trauma patients. Further randomised controlled trials are needed to establish the most effective fluid resuscitation strategy.Peer reviewe

A strong law of large numbers for branching processes: almost sure spine events

We demonstrate a novel strong law of large numbers for branching processes, with a simple proof via measure-theoretic manipulations and spine theory. Roughly speaking, any sequence of events that eventually occurs almost surely for the spine entails the almost sure convergence of a certain sum over particles in the population.Comment: 6 page

General tooth boundary conditions for equation free modelling

We are developing a framework for multiscale computation which enables models at a ``microscopic'' level of description, for example Lattice Boltzmann, Monte Carlo or Molecular Dynamics simulators, to perform modelling tasks at ``macroscopic'' length scales of interest. The plan is to use the microscopic rules restricted to small "patches" of the domain, the "teeth'', using interpolation to bridge the "gaps". Here we explore general boundary conditions coupling the widely separated ``teeth'' of the microscopic simulation that achieve high order accuracy over the macroscale. We present the simplest case when the microscopic simulator is the quintessential example of a partial differential equation. We argue that classic high-order interpolation of the macroscopic field provides the correct forcing in whatever boundary condition is required by the microsimulator. Such interpolation leads to Tooth Boundary Conditions which achieve arbitrarily high-order consistency. The high-order consistency is demonstrated on a class of linear partial differential equations in two ways: firstly through the eigenvalues of the scheme for selected numerical problems; and secondly using the dynamical systems approach of holistic discretisation on a general class of linear \textsc{pde}s. Analytic modelling shows that, for a wide class of microscopic systems, the subgrid fields and the effective macroscopic model are largely independent of the tooth size and the particular tooth boundary conditions. When applied to patches of microscopic simulations these tooth boundary conditions promise efficient macroscale simulation. We expect the same approach will also accurately couple patch simulations in higher spatial dimensions.Comment: 22 page

Exposing the dressed quark's mass

This snapshot of recent progress in hadron physics made in connection with QCD's Dyson-Schwinger equations includes: a perspective on confinement and dynamical chiral symmetry breaking (DCSB); a pre'cis on the physics of in-hadron condensates; results on the hadron spectrum, including dressed-quark-core masses for the nucleon and Delta, their first radial excitations, and the parity-partners of these states; an illustration of the impact of DCSB on the electromagnetic pion form factor, thereby exemplifying how data can be used to chart the momentum-dependence of the dressed-quark mass function; and a prediction that F_1^{p,d}/F_1^{p,u} passes through zero at Q^2\approx 5m_N^2 owing to the presence of nonpointlike scalar and axial-vector diquark correlations in the nucleon.Comment: 10 pages, 4 figures, 2 tables. Contribution to the Proceedings of the 4th Workshop on Exclusive Reactions at High Momentum Transfer, Thomas Jefferson National Accelerator Facility Newport News, Virginia, 18-21 May 201