From bedside to bench: Comroe and dripps revisited

Twenty-five years ago a paper published in Science by Julius Comroe and Robert Dripps purported to demonstrate that 41 per cent of all articles judged to be essential for later clinical advances were not clinically oriented at the time of the study and 62 per cent of key articles were the result of basic research. Since that analysis, support for basic research has increased in the G7 countries. In the UK, Research Council expenditure on basic research has increased from a low of £444 million (or 42 per cent of total civil R&D) in 1991/92 to £769 million (or 61 per cent of total civil R&D) in 1998/99. Although it would be difficult to argue that Comroe and Dripps were directly responsible for a strategic shift (or drift) in the type of science supported by research funders, their arguments are often cited (albeit at times implicitly) in support of the increased funding for basic biomedical research. In 1987 Richard Smith wrote a critical paper reassessing Comroe and Dripps. His main argument was that the original study was in itself ‘unscientific’ and that it should be “followed by bigger and better studies”. This study is, in part, an answer to that challenge. Given the increased support for basic research, and the apparent importance based on the work of Comroe and Dripps, we felt it was important to investigate Smith’s comments by replicating Comroe and Dripps’s study and at the same time try to improve upon the methodology. The current project had two objectives: 1. To see if the original Comroe and Dripps’s methodology was ‘replicable’. 2. To validate the key findings of Comroe and Dripps. By looking at neonatal intensive care (NIC), we concluded that Comroe and Dripps’ study – as reported – is not repeatable, reliable or valid, and thus is an insufficient evidence base for increased expenditure on basic biomedical research. We did, however, develop an alternative methodology which used bibliographic databases and bibliometric techniques to describe the research underpinning five of the most important clinical advances in NIC, as identified through a Delphi survey. Using the revised bibliometric protocol, we demonstrated that after a time-lag of about 17 years, between 2 and 21 per cent of research underpinning the clinical advances could be described as basic. This observation is at odds with Comroe and Dripps’s finding that 62 per cent of key research articles judged to be essential for latter clinical advance were the result of basic research. In reaching this conclusion we are acutely aware of the significant limitations to the revised methodology and, therefore, we caution against the over-interpretation of our results. However, we would argue that there needs to be a greater understanding of how basic research supports healthcare and hope this report will inform part of this wider debate.R&D Directorate of the NHS Executive London; Wellcome Trus

NASTRAN solutions of problems described by simultaneous parabolic differential equations

NASTRAN solution techniques are shown for a numerical analysis of a class of coupled vector flow processes described by simultaneous parabolic differential equations. To define one physical problem type where equations of this form arise, the differential equations describing the coupled transfers of heat and mass in mechanical equilibrium with negligible mass average velocity are presented and discussed. Also shown are the equations describing seepage when both electrokinetic and hydrodynamic forces occur. Based on a variational statement of the general problem type, the concepts of scalar transfer elements and parallel element systems are introduced. It is shown that adoptation of these concepts allows the direct use of NASTRAN's existing Laplace type elements for uncoupled flow (the heat transfer elements) for treating multicomponent coupled transfer. Sample problems are included which demonstrate the application of these techniques for both steady-state and transient problems

Extraction of tidal channel networks from airborne scanning laser altimetry and aerial photography

The study of the morphodynamics of tidal channel networks is important because of their role in tidal propagation and the evolution of salt-marshes and tidal flats. Channel dimensions range from tens of metres wide and metres deep near the low water mark to only 20-30cm wide and 20cm deep for the smallest channels on the marshes. The conventional method of measuring the networks is cumbersome, involving manual digitising of aerial photographs. This paper describes a semi-automatic knowledge-based network extraction method that is being implemented to work using airborne scanning laser altimetry (and later aerial photography). The channels exhibit a width variation of several orders of magnitude, making an approach based on multi-scale line detection difficult. The processing therefore uses multi-scale edge detection to detect channel edges, then associates adjacent anti-parallel edges together to form channels using a distance-with-destination transform. Breaks in the networks are repaired by extending channel ends in the direction of their ends to join with nearby channels, using domain knowledge that flow paths should proceed downhill and that any network fragment should be joined to a nearby fragment so as to connect eventually to the open sea

NASTRAN cyclic symmetry capability

A development for NASTRAN which facilitates the analysis of structures made up of identical segments symmetrically arranged with respect to an axis is described. The key operation in the method is the transformation of the degrees of freedom for the structure into uncoupled symmetrical components, thereby greatly reducing the number of equations which are solved simultaneously. A further reduction occurs if each segment has a plane of reflective symmetry. The only required assumption is that the problem be linear. The capability, as developed, will be available in level 16 of NASTRAN for static stress analysis, steady state heat transfer analysis, and vibration analysis. The paper includes a discussion of the theory, a brief description of the data supplied by the user, and the results obtained for two example problems. The first problem concerns the acoustic modes of a long prismatic cavity imbedded in the propellant grain of a solid rocket motor. The second problem involves the deformations of a large space antenna. The latter example is the first application of the NASTRAN Cyclic Symmetry capability to a really large problem

HIEN-LO: An experiment for charge determination of cosmic rays of interplanetary and solar origin

The experiment is designed to measure the heavy ion environment at low altitude (HIEN-LO) in the energy range 0.3 to 100 MeV/nucleon. In order to cover this wide energy range a complement of three sensors is used. A large area ion drift chamber and a time-of-flight telescope are used to determine the mass and energy of the incoming cosmic rays. A third omnidirectional counter serves as a proton monitor. The analysis of mass, energy and incoming direction in combination with the directional geomagnetic cut-off allows the determination of the ionic charge of the cosmic rays. The ionic charge in this energy range is of particular interest because it provides clues to the origin of these particles and to the plasma conditions at the acceleration site. The experiment is expected to be flown in 1988/1989

High mass X-ray binaries in the NIRorbital solutions of two highly obscured systems

The maximum mass of a neutron star (NS) is poorly defined. Theoretical attempts to define this mass have thus far been unsuccessful. Observational results currently provide the only means of narrowing this mass range down. Eclipsing X-ray binary (XRB) pulsar systems are the only interacting binaries in which the mass of the NS may be measured directly. Only 10 such systems are known to exist, 6 of which have yielded NS masses in the range 1.06 - 1.86 M$_{\odot}$.We present the first orbital solutions of two further eclipsing systems, OAO 1657-415 and EXO 1722-363, whose donor stars have only recently been identified. Using observations obtained using the VLT/ISAAC NIR spectrograph, our initial work was concerned with providing an accurate spectral classification of the two counterpart stars, leading to a consistent explanation of the mechanism for spin period evolution of OAO 1657-415. Calculating radial velocities allowed orbital solutions for both systems to be computed. These are the first accurate determinations of the NS and counterpart masses in XRB pulsar systems to be made employing NIR spectroscopy.Comment: 5 pages, 3 figures, contribution to the proceedings of "The multi-wavelength view of hot, massive stars", 39th Li`ege Int. Astroph. Coll., 12-16 July 201

Numerical simulations of strong incompressible magnetohydrodynamic turbulence

Magnetised plasma turbulence pervades the universe and is likely to play an important role in a variety of astrophysical settings. Magnetohydrodynamics (MHD) provides the simplest theoretical framework in which phenomenological models for the turbulent dynamics can be built. Numerical simulations of MHD turbulence are widely used to guide and test the theoretical predictions; however, simulating MHD turbulence and accurately measuring its scaling properties is far from straightforward. Computational power limits the calculations to moderate Reynolds numbers and often simplifying assumptions are made in order that a wider range of scales can be accessed. After describing the theoretical predictions and the numerical approaches that are often employed in studying strong incompressible MHD turbulence, we present the findings of a series of high-resolution direct numerical simulations. We discuss the effects that insufficiencies in the computational approach can have on the solution and its physical interpretation

Vacuum ultraviolet photoabsorption of prime ice analogues of Pluto and Charon

Here we present the first Vacuum UltraViolet (VUV) photoabsorption spectra of ice analogues of Pluto and Charon ice mixtures. For Pluto the ice analogue is an icy mixture containing nitrogen (N2), carbon monoxide (CO), methane (CH4) and water (H2O) prepared with a 100:1:1:3 ratio, respectively. Photoabsorption of icy mixtures with and without H2O were recorded and no significant changes in the spectra due to presence of H2O were observed. For Charon a VUV photoabsorption spectra of an ice analogue containing ammonia (NH3) and H2O prepared with a 1:1 ratio was recorded, a spectrum of ammonium hydroxide (NH4OH) was also recorded. These spectra may help to interpret the P-Alice data from New Horizons