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

Limited Equity Cooperatives: The Non-Economic Value of Homeownership

Economists have argued there are two main purposes of homeownership. The first is housing as a utility for consumption, and the second is housing as an investment vehicle. Legal scholars, on the other hand, view homeownership in more personal terms. Margaret Radin, in her watershed article, argues that homeownership is so closely imbued with the person that it is affirmatively part of one‘s self—the personhood of property. Radin suggests that one‘s home is such a part of the way a person constitutes oneself that the property becomes an element of personhood, something no longer entirely external to the person. In response, however, Stephanie Stern argues there is little to no empirical evidence to support this proposition. She argues instead that homeownership has been provided unwarranted legal and economic protection, and has no more intrinsic value to the individual than any other possession. Many Americans embrace homeownership for reasons beyond investment. This Article evaluates the meaning of homeownership, particularly when wealth creation is not the primary goal. There are non-economic values to homeownership, particularly for low- and moderate-income residents, which remain unexplored. This Article seeks to evaluate the arguments of legal scholars and economists in light of the limited equity cooperative, a form of homeownership that significantly limits equity appreciation for the owner. While the limited equity cooperative is an older form of homeownership, it has reemerged as a valued homeownership option, especially, though not exclusively, for low- and moderate-income residents. This Article works to dispel the argument that homeownership, particularly limited equity cooperative homeownership, is less valuable for a homeowner because equity appreciation is restricted or because limited equity cooperatives are a non-traditional form of homeownership. Part I of the Article will provide a brief history of the federal government‘s efforts to promote homeownership, particularly for low- and moderate-income individuals. Part II will provide a brief description of the different types of traditional homeownership models common in the United States. Part III will provide a history of and evaluate one of the alternatives to the traditional homeownership model—the housing cooperative, specifically, the limited equity cooperative. Part IV concludes with an analysis of the non-economic value of homeownership as it relates to limited equity cooperative homeownership

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

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

‘Islands of Innovation’ and diversities of innovation in the UK and France

This paper explores diverging patterns of innovation and regional development in two ‘islands of innovation’. In the early 2000s the growth trajectories of Grenoble and Oxfordshire were compared (Lawton Smith 2003). The focus was on national laboratories as territorial actors in the clustering of high-tech firms. Building on longitudinal data collected since 2003 the theme shifts in this study to the forms that government intervention takes through investments in knowledge organisations in high tech economies and how that leads to particular specialisations of technological advance. While there are many similarities, there are differences in starting points and structures, leading to diversities in innovation. The analysis shows how both are embedded in their national situations and opportunities for development. We focus on two key elements in sustaining clusters of innovation, those of highly skilled labour and networks. We show that in Grenoble, the clusters are orchestrated information and project-based while in Oxfordshire they are labour market dominated and organic. We demonstrate complementary relationships between the national and regional level policy formation and implementation. In both cases importance of place is sustained over time but for different reasons

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