Quaternionic Formulation of the Dirac Equation

The Dirac equation with Lorentz violation involves additional coefficients and yields a fourth-order polynomial that must be solved to yield the dispersion relation. The conventional method of taking the determinant of $4\times 4$ matrices of complex numbers often yields unwieldy dispersion relations. By using quaternions, the Dirac equation may be reduced to $2 \times 2$ form in which the structure of the dispersion relations become more transparent. In particular, it is found that there are two subsets of Lorentz-violating parameter sets for which the dispersion relation is easily solvable. Each subset contains half of the parameter space so that all parameters are included.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28-July 2, 201

Scaling-up or Going-viral? Comparing self-help housing and community land trust facilitation

This paper explores two sector-based case studies of social innovation in community-led housing that have taken root in the last ten years: community land trusts (CLTs) set up to ensure access to affordable homes in perpetuity and self-help housing organisations set up to bring empty homes back into use. These innovations benefit from a groundswell of support, as their specialised local focus and people-centre approach to housing has strong resonance with policy agendas of localism and community empowerment in England. Yet to take root such innovations need more than rhetorical support; they require practical and ideological strengthening to secure flows of resources and legitimacy required for survival alongside professionalised and better resourced forms of organisation. This paper compares the forms of support provided by intermediary organisations that have been used to facilitate the growth and diffusion of these community-led housing models. It describes how the CLT sector has scaled up to create a formal institutional framework operating at different spatial scales to support locally-rooted community groups and considers the implications of this for the self-help housing sector, which has shown a preference for ‘viral’ solutions that focus on small-scale projects and community leadership. While intermediary support is clearly of importance, there are tensions in its provision, as sectors that scale up may begin to question local independence and dilute community ethos, while viral solutions may face challenges in accessing technical skills and resources without becoming overburdened or diverted from initial objectives. The paper concludes that while partnerships with technical experts that act as intermediaries may be crucial for the diffusion and expansion of CLTs and self-help housing, there are tensions in accessing technical skills and resources in a manner that maintains the local scale, accountability and unique added value of community-led housing

Let to Birmingham: 2016 case study report

Social Lettings Agencies (SLAs) have been described succinctly by Shelter Scotland (Evans, 2015) as agencies that “help people access the PRS who are homeless or on low-incomes”. SLA is a general term applied to schemes that secure access to decent, affordable private rental accommodation for households in need and on low incomes who would previously have been likely to access social housing. The growth of SLAs has been a consequence of the falling supply of social housing, growth in the private rented sector, expansion of ‘housing options’ approaches since the Homelessness Act 2002 and discharge of homeless duties in the private rented sector since the Localism Act 2011. The West Midlands Housing Officers Group has supported this project by the Housing and Communities Research Group at the University of Birmingham to explore the current and potential future role of SLAs in the region. Its relevance to current policy has increased considerably since the time of its commissioning. This report covers the ‘second wave’ of research on Let to Birmingham undertaken in Autumn 2016. It supplements our earlier report in Autumn 2015 which covered the background to the establishment of Let to Birmingham in January 2014 as a social lettings agency by Birmingham City Council in partnership with Omega Lettings (now a division of Mears) and the first 18 months of its operation (Mullins, Joseph and Nechita 2015)

Social Lettings Agencies in the West Midlands

Social Lettings Agencies (SLAs) have been described succinctly by Shelter Scotland (Evans, 2015) as agencies that ‘help people access the PRS who are homeless or on low-incomes”. SLA is a general term applied to schemes that secure access to decent, affordable private rental accommodation for households in need and on low incomes who would previously have been likely to access social housing. The growth of SLAs has been a consequence of the falling supply of social housing, growth in the private rented sector, expansion of ‘housing options’ approaches since the Homelessness Act 2002 and discharge of homeless duties in the private rented sector since the Localism Act 2011. The West Midlands Housing Officers Group has supported this project by the Housing and Communities Research Group at the University of Birmingham to explore the current and potential future role of SLAs in the region. Its relevance to current policy has increased considerably since the time of its commissioning. Changing market conditions and in particular the growing gap between social housing supply and demand and rising homelessness have led to increasing policy support for SLAs in England. In 2015 the right leaning Centre for Social Justice (CSJ) recommended the Government to ‘greatly expand the role of social lettings agencies across the country’ (Winterburn, 2015 p.3). Key aims of SLAs were considered by CSJ as being ‘to minimise risk to landlords so they are willing to let to benefit claimants (ibid p.61) ’ and to provide a measure of support for tenancy sustainability ‘typically SLAs will have support workers who regularly check in on the vulnerable’ (ibid p.62). By 2017 Theresa May’s Conservative Government as part of its plan to ‘fix our broken housing market’ wanted to ‘consider whether SLAs can be an effective tool for securing more housing for people who would otherwise struggle – providing security for landlords and support for tenants to help strengthen and sustain tenancies’ (DCLG 2017, p.66) . This parallels developments in other countries with an insufficient supply of social housing such as Belgium, Ireland and Hungary where the idea of SLAs has been more prevalent than in England to date (De Decker, 2002, Laylor, 2014, Hegedus et al 2014). The project brief set out the purpose of the project to explore the scope for SLAs to address the needs of low income households seeking decent, secure and affordable rented homes in the Midlands. This would include an in-depth study of Let to Birmingham SLA, case studies of other SLAs in the region and peer learning events to share experience and ideas about properties, people and process and in what respects PRS could become the ‘new social housing’ (in terms of security, affordability and quality issues)

Anisotropic Small-Polaron Hopping In W:Bivo4 Single Crystals

DC electrical conductivity, Seebeck and Hall coefficients are measured between 300 and 450 K on single crystals of monoclinic bismuth vanadate that are doped n-type with 0.3% tungsten donors (W:BiVO4). Strongly activated small-polaron hopping is implied by the activation energies of the Arrhenius conductivities (about 300 meV) greatly exceeding the energies characterizing the falls of the Seebeck coefficients' magnitudes with increasing temperature (about 50 meV). Small-polaron hopping is further evidenced by the measured Hall mobility in the ab-plane (10(-1) cm(2) V-1 s(-1) at 300 K) being larger and much less strongly activated than the deduced drift mobility (about 5 x 10(-5) cm(2) V-1 s(-1) at 300 K). The conductivity and n-type Seebeck coefficient is found to be anisotropic with the conductivity larger and the Seebeck coefficient's magnitude smaller and less temperature dependent for motion within the ab-plane than that in the c-direction. These anisotropies are addressed by considering highly anisotropic next-nearest-neighbor (approximate to 5 angstrom) transfers in addition to the somewhat shorter (approximate to 4 angstrom), nearly isotropic nearest-neighbor transfers. (C) 2015 AIP Publishing LLC.U.S. Department of Energy (DOE), DE-FG02-09ER16119Welch Foundation Grant F-1436Hemphill-Gilmore Endowed FellowshipNSF MIRT DMR 1122603Chemical EngineeringTexas Materials InstituteChemistr

Political economy, poverty, and polycentrism in the Global Environment Facility’s Least Developed Countries Fund (LDCF) for climate change adaptation

Climate change adaptation refers to altering infrastructure, institutions or ecosystems to respond to the impacts of climate change. Least developed countries often lack the requisite capacity to implement adaptation projects. The Global Environment Facility’s Least Developed Countries Fund (LDCF) is a scheme where industrialised countries have disbursed $934.5 million in voluntary contributions to support 213 adaptation projects across 51 least developed countries. But how effective are its efforts—and what sort of challenges have arisen as it implements projects? To provide some answers, this article documents the presence of four “political economy” attributes of adaptation projects—processes we have termed enclosure, exclusion, encroachment and entrenchment—cutting across economic, political, ecological and social dimensions. Based on extensive field research, we find the four processes at work simultaneously in our case studies of five LDCF projects being implemented in Bangladesh, Bhutan, Cambodia, the Maldives and Vanuatu. The article concludes with a discussion of the broader implications of the political economy of adaptation for analysts, program managers and climate researchers at large. In sum, the politics of adaptation must be taken into account so that projects can maximise their efficacy and avoid marginalising those most vulnerable to the impacts of climate change

LNK suppresses interferon signaling in melanoma.

LNK (SH2B3) is a key negative regulator of JAK-STAT signaling which has been extensively studied in malignant hematopoietic diseases. We found that LNK is significantly elevated in cutaneous melanoma; this elevation is correlated with hyperactive signaling of the RAS-RAF-MEK pathway. Elevated LNK enhances cell growth and survival in adverse conditions. Forced expression of LNK inhibits signaling by interferon-STAT1 and suppresses interferon (IFN) induced cell cycle arrest and cell apoptosis. In contrast, silencing LNK expression by either shRNA or CRISPR-Cas9 potentiates the killing effect of IFN. The IFN-LNK signaling is tightly regulated by a negative feedback mechanism; melanoma cells exposed to IFN upregulate expression of LNK to prevent overactivation of this signaling pathway. Our study reveals an unappreciated function of LNK in melanoma and highlights the critical role of the IFN-STAT1-LNK signaling axis in this potentially devastating disease. LNK may be further explored as a potential therapeutic target for melanoma immunotherapy