126,023 research outputs found
What do students do? Training, research and learning: developing skills for the next generation of near-surface geophysicists
In the past decade, degree programmes throughout Europe have changed dramatically and near-surface geophysics is now commonly taught as a minor component of other undergraduate geoscience and related degree programmes. As a consequence, there has been a distinct change in the nature, scope and content of geophysical degrees and the skills set that graduates obtain throughout their studies. As an introduction to the Special Issue on Student-based Research, this commentary article discusses the expectations of employers, the competencies and skills of our undergraduate and postgraduate students and how these have changed over time. We highlight skill gaps and suggest ways in which the near-surface geophysical community can address these needs in a pragmatic and cost efficient manner. We hope to illustrate that a greater collaboration between industry and academia is the way forward and that innovative, cross-sector approaches to student learning and research are the solution to at least some of our problems
A comparison of sequential total and activated white cell count in patients undergoing coronary artery bypass grafting, using cardiopulmonary bypass, with and without a white cell filter
Introduction
Cardiopulmonary bypass (CPB) has been shown to induce a systemic inflammatory response similar to the local reaction seen after tissue damage [1]. This leads to the release of toxic substances, such as elastase, which cause endothelial damage and may adversely affect outcome [2]. Use of a leucocyte depleting arterial line filter is one of many anti-inflammatory strategies that are undergoing evaluation. Leucocyte depleting filters may be capable of selectively removing activated white cells [3], but this has not been proved in vivo. The aim of the present study was to compare sequential total and activated white cells during CPB, using either a leucocyte depleting or standard arterial line filter.
Materials and methods
After local ethical committee approval, 20 patients undergoing coronary artery bypass grafting using CPB were prospectively randomly allocated to have either a Leukogard LG–6 (Pall Biomedical, Portsmouth, UK) or a nonleucocyte depleting filter inserted into the arterial line of the CPB circuit. Arterial limb blood samples were taken immediately after institution of CPB (0min) and at 10–min intervals throughout the bypass period. Activated white cells were identified using nitroblue tetrazolium, then both total and activated white cell numbers counted after staining with Leucoplate.Results
Table 1 shows the number of white cells counted/1.25 ? l (volume of a single channel of Nageotte counting chamber) using light microscopy (× 25).Conclusion
The LG6 leucocyte filter reduces the total white cell count and is capable of selectively removing activated white cells during CPB. The exact relationship between leucocyte depletion and improved patient outcome still remains unclear
A comparative study of using spindle motor power and eddy current for the detection of tool conditions in milling processes
This paper investigates the use of the power of the driving motor of a CNC spindle in comparison to two perpendicular eddy current sensors for the detection of tool wear in milling processes. Monitoring the power through the current profile is a low cost system which has been utilised in this study as an attempt to detect the fluctuation in the motor load as a result of the conditions of the cutting tool. Eddy current sensors are dedicated sensors that are installed on the spindle to measure the vibration of the rotating spindle in two axes. Experimental work has been conducted using fresh and worn tools to investigate the effect of tool conditions on the two sensory systems. Time domain features are utilised to compare between the two sensors in relation to this application. The results indicate that Eddy current sensors are found to be more successful and sensitive, in general, than the power of the motor in detecting the changes of the cutting tools during the machining operation. However, the kurtosis value of the power of the spindle has been found to be successful in predicting the tool conditions with high sensitivity
The Carboniferous Southern Pennine Basin, UK
Many of the Carboniferous outcrops located in the Derbyshire region of the Peak District National Park, UK, have provided sites for both significant and pioneering research relating to the clastic sedimentology of marine palaeoenvironments, particularly so during the 1960s and 1970s when early models describing the sedimentary architecture of fluvio-deltaic, submarine slope and deep-marine submarine-fan sedimentation were first developed. The area was subject to hydrocarbon exploration from the 1920s to 1950s, which although unsuccessful in economic terms left a legacy of sub-surface data. Despite a long-history of sedimentological research, the deposits exposed at several classic localities in the Pennine Basin continue to broaden and challenge our current understanding of sedimentary processes to this day
Preliminary soilwater conductivity analysis to date clandestine burials of homicide victims
This study reports on a new geoscientific method to estimate the post-burial interval (PBI) and potential post-mortem interval (PMI) date of homicide victims in clandestine graves by measuring decomposition fluid conductivities. Establishing PBI/PMI dates may be critical for forensic investigators to establish time-lines to link or indeed rule out suspects to a crime. Regular in situ soilwater analysis from a simulated clandestine grave (which contained a domestic buried pig carcass) in a semi-rural environment had significantly elevated conductivity measurements when compared to background values. A temporal rapid increase of the conductivity of burial fluids was observed until one-year post-burial, after this values slowly increased until two years (end of the current study period). Conversion of x-axis from post-burial days to 'accumulated degree days' (ADDs) corrected for both local temperature variations and associated depth of burial and resulted in an improved fit for multiple linear regression analyses. ADD correction also allowed comparison with a previous conductivity grave study on a different site with a different soil type and environment; this showed comparable results with a similar trend observed. A separate simulated discovered burial had a conductivity estimated PBI date that showed 12% error from its actual burial date. Research is also applicable in examining illegal animal burials; time of burial and waste deposition. Further research is required to extend the monitoring period, to use human cadavers and to repeat this with other soil types and depositional environments
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The V5A13.1 envelope glycoprotein deletion mutant of mouse hepatitis virus type-4 is neuroattenuated by its reduced rate of spread in the central nervous system.
Following intracerebral inoculation of adult Balb/c Byj mice, the MHV-4 strain of mouse hepatitis virus (MHV) had an LD50 of less than 0.1 PFU, whereas its monoclonal antibody resistant variant V5A13.1 had an LD50 of 10(4.2) PFU. To determine the basis for this difference in neurovirulence we have studied the acute central nervous system (CNS) infection of these two viruses by in situ hybridization. Both viruses infected the same, specific neuroanatomical areas, predominantly neurons, and spread via the cerebrospinal fluid, along neuronal pathways and between adjacent cells. The neuronal nuclei infected and the spread of virus within the brain are described. The main difference between the parental and variant viruses was the rate at which the infection spread. MHV-4 spread rapidly, destroying large numbers of neurons and the animals died within 4 days of infection. The variant virus spread to the same areas of the brain but at a slower rate. This difference in the rate of virus spread was also apparent from the brain virus titers. The slower rate of spread of the variant virus appears to allow intervention by the immune response. Consistent with this, the variant virus spread slowly in athymic nu/nu mice, but in the absence of an intact immune response, infection and destruction of neurons eventually reached the same extent as that of the parental virus and the mice died within 6 days of infection. We conclude that the V5A13.1 variant of MHV-4 is neuroattenuated by its slower rate of spread in the CNS
MetaboNetworks, an interactive Matlab-based toolbox for creating, customizing and exploring sub-networks from KEGG.
Summary: MetaboNetworks is a tool to create custom sub-networks in Matlab using main reaction pairs as defined by the Kyoto Encyclopaedia of Genes and Genomes and can be used to explore transgenomic interactions, for example mammalian and bacterial associations. It calculates the shortest path between a set of metabolites (e.g. biomarkers from a metabonomic study) and plots the connectivity between metabolites as links in a network graph. The resulting graph can be edited and explored interactively. Furthermore, nodes and edges in the graph are linked to the Kyoto Encyclopaedia of Genes and Genomes compound and reaction pair web pages. Availability and implementation: MetaboNetworks is available from http://www.mathworks.com/matlabcentral/fileexchange/42684. Contact: [email protected] or [email protected] Supplementary information: Supplementary data are available at Bioinformatics online
Dynamo driven accretion discs and dwarf nova eruptions
We explore the consequences of a magnetic dynamo origin for the viscosity in
accretion discs, for the structure and evolution of discs in dwarf nova
systems. We propose that the rapid cooling that sets in at the end of a dwarf
nova eruption acts to inhibit the Balbus-Hawley instability, and thereby to
quench dynamo action and so reduce disc viscosity. We demonstrate that a
modified disc instability model can reproduce the basic properties of dwarf
nova eruptions, as well as some properties of quiescent discs. We also discuss
some observational consequences of our model.Comment: uu-encoded gz-compressed Postscript file, 18 pages including 6
figures. ApJ in pres
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