Combining optical trapping in a microfluidic channel with simultaneous micro-Raman spectroscopy and motion detection.

Since their invention by Ashkin optical tweezers have demonstrated their ability and versatility as a non-invasive tool for micromanipulation. One of the most useful additions to the basic optical tweezers system is micro-Raman spectroscopy, which permits highly sensitive analysis of single cells or particles. We report on the development of a dual laser system combining two spatial light modulators to holographically manipulate multiple traps (at 1064nm) whilst undertaking Raman spectroscopy using a 532nm laser. We can thus simultaneously trap multiple particles and record their Raman spectra, without perturbing the trapping system. The dual beam system is built around micro-fluidic channels where crystallisation of calcium carbonate occurs on polymethylmethacrylate (PMMA) beads. The setup is designed to simulate at a microscopic level the reactions that occur on items in a dishwasher, where permanent filming of calcium carbonate on drinking glasses is a problem. Our system allows us to monitor crystal growth on trapped particles in which the Raman spectrum and changes in movement of the bead are recorded. Due to the expected low level of crystallisation on the bead surfaces this allows us to obtain results quickly and with high sensitivity. The long term goal is to study the development of filming on samples in-situ with the microfluidic system acting as a model dishwasher

Emission Measures and Emission-measure-weighted Temperatures of Shocked ISM and Ejecta in Supernova Remnants

A goal of supernova remnant (SNR) evolution models is to relate fundamental parameters of a supernova (SN) explosion and progenitor star to the current state of its SNR. The SNR hot plasma is characterized by its observed X-ray spectrum, which yields electron temperature, emission measure and abundances. Depending on their brightness, the properties of the plasmas heated by the SNR forward shock, reverse shock or both can be measured. The current work utilizes models which are spherically symmetric. One dimensional hydrodynamic simulations are carried out for SNR evolution prior to onset of radiative losses. From these, we derive dimensionless emission measures and emission-measure-weighted temperatures, and we present fitting formulae for these quantities as functions of scaled SNR time. These models allow one to infer SNR explosion energy, circumstellar medium density, age, ejecta mass and ejecta density profile from SNR observations. The new results are incorporated into the SNR modelling code SNRPy. The code is demonstrated with application to three historical SNRs: Kepler, Tycho and SN1006.Comment: 50 pages, 10 figures, 5 table

East Midlands skills priorities statement academic year 2011-2012

The East Midlands Skills Priorities Statement sets out the skills required to support economic growth and recovery in the region. The statement presents priorities for the academic year 2011-2012 for skills at all levels for those aged 16 and above. It is based on the latest labour market intelligence and information on provision and includes prospects to 2017

Conductance quantization and snake states in graphene magnetic waveguides

We consider electron waveguides (quantum wires) in graphene created by suitable inhomogeneous magnetic fields. The properties of uni-directional snake states are discussed. For a certain magnetic field profile, two spatially separated counter-propagating snake states are formed, leading to conductance quantization insensitive to backscattering by impurities or irregularities of the magnetic field.Comment: 5 pages, 4 figures, final version accepted as Rapid Comm. in PR

All work and no pay: consequences of unpaid work experience in the creative industries

This research note evaluates the benefits and pitfalls of unpaid work as an entry route into employment in the creative industries and investigates the consequences of this practice for those who already work in the sector. Based on a qualitative study of perspectives of stakeholders in unpaid work, this article argues that the social capital thesis, often used as a rationale for unpaid work, inadequately explains the practice of unpaid work experience, primarily because it does not take cognisance of the consequences of this practice for other people working in the sector. The study also highlights methodological issues that need to be considered in the future. As well as the importance of a plurality of stakeholder perspectives, the study emphasizes the need to consider the perspectives of those who are excluded from unpaid work and those who are potentially displaced by it

Why Trade Associations Matter: Exploring Function, Meaning, and Influence

We explore the organizational characteristics of trade associations (TAs) and suggest theoretical approaches for undertaking research into or involving TAs in management and organization studies. Through emphasizing the role of TAs within and between industries and at the interface of business and society, we consider how TAs generate meaning and influence

Environmental modeling and recognition for an autonomous land vehicle

An architecture for object modeling and recognition for an autonomous land vehicle is presented. Examples of objects of interest include terrain features, fields, roads, horizon features, trees, etc. The architecture is organized around a set of data bases for generic object models and perceptual structures, temporary memory for the instantiation of object and relational hypotheses, and a long term memory for storing stable hypotheses that are affixed to the terrain representation. Multiple inference processes operate over these databases. Researchers describe these particular components: the perceptual structure database, the grouping processes that operate over this, schemas, and the long term terrain database. A processing example that matches predictions from the long term terrain model to imagery, extracts significant perceptual structures for consideration as potential landmarks, and extracts a relational structure to update the long term terrain database is given

Listeriolysin S, a Novel Peptide Haemolysin Associated with a Subset of Lineage I Listeria monocytogenes

peer-reviewedStreptolysin S (SLS) is a bacteriocin-like haemolytic and cytotoxic virulence factor that plays a key role in the virulence of Group A Streptococcus (GAS), the causative agent of pharyngitis, impetigo, necrotizing fasciitis and streptococcal toxic shock syndrome. Although it has long been thought that SLS and related peptides are produced by GAS and related streptococci only, there is evidence to suggest that a number of the most notorious Gram-positive pathogenic bacteria, including Listeria monocytogenes, Clostridium botulinum and Staphylococcus aureus, produce related peptides. The distribution of the L. monocytogenes cluster is particularly noteworthy in that it is found exclusively among a subset of lineage I strains; i.e., those responsible for the majority of outbreaks of listeriosis. Expression of these genes results in the production of a haemolytic and cytotoxic factor, designated Listeriolysin S, which contributes to virulence of the pathogen as assessed by murine- and human polymorphonuclear neutrophil–based studies. Thus, in the process of establishing the existence of an extended family of SLS-like modified virulence peptides (MVPs), the genetic basis for the enhanced virulence of a proportion of lineage I L. monocytogenes may have been revealed.Work is funded by the Irish Government under the National Development Plan, through a Science Foundation Ireland Investigator award to CH, PR and PC (06/IN.1/B98)

Contributory factors in surgical incidents as delineated by a confidential reporting system

Background Confidential reporting systems play a key role in capturing information about adverse surgical events. However, the value of these systems is limited if the reports that are generated are not subjected to systematic analysis. The aim of this study was to provide the first systematic analysis of data from a novel surgical confidential reporting system to delineate contributory factors in surgical incidents and document lessons that can be learned. Methods One-hundred and forty-five patient safety incidents submitted to the UK Confidential Reporting System for Surgery over a 10-year period were analysed using an adapted version of the empirically-grounded Yorkshire Contributory Factors Framework. Results The most common factors identified as contributing to reported surgical incidents were cognitive limitations (30.09%), communication failures (16.11%) and a lack of adherence to established policies and procedures (8.81%). The analysis also revealed that adverse events were only rarely related to an isolated, single factor (20.71%) – with the majority of cases involving multiple contributory factors (79.29% of all cases had more than one contributory factor). Examination of active failures – those closest in time and space to the adverse event – pointed to frequent coupling with latent, systems-related contributory factors. Conclusions Specific patterns of errors often underlie surgical adverse events and may therefore be amenable to targeted intervention, including particular forms of training. The findings in this paper confirm the view that surgical errors tend to be multi-factorial in nature, which also necessitates a multi-disciplinary and system-wide approach to bringing about improvements