Photon orbital angular momentum and torque metrics for single telescopes and interferometers

Context. Photon orbital angular momentum (POAM) is normally invoked in a quantum mechanical context. It can, however, also be adapted to the classical regime, which includes observational astronomy. Aims. I explain why POAM quantities are excellent metrics for describing the end-to-end behavior of astronomical systems. To demonstrate their utility, I calculate POAM probabilities and torques from holography measurements of EVLA antenna surfaces. Methods. With previously defined concepts and calculi, I present generic expressions for POAM spectra, total POAM, torque spectra, and total torque in the image plane. I extend these functional forms to describe the specific POAM behavior of single telescopes and interferometers. Results. POAM probabilities of spatially uncorrelated astronomical sources are symmetric in quantum number. Such objects have zero intrinsic total POAM on the celestial sphere, which means that the total POAM in the image plane is identical to the total torque induced by aberrations within propagation media & instrumentation. The total torque can be divided into source- independent and dependent components, and the latter can be written in terms of three illustrative forms. For interferometers, complications arise from discrete sampling of synthesized apertures, but they can be overcome. POAM also manifests itself in the apodization of each telescope in an array. Holography of EVLA antennas observing a point source indicate that ~ 10% of photons in the n = 0 state are torqued to n != 0 states. Conclusions. POAM quantities represent excellent metrics for characterizing instruments because they are used to simultaneously describe amplitude and phase aberrations. In contrast, Zernike polynomials are just solutions of a differential equation that happen to ~ correspond to specific types of aberrations and are typically employed to fit only phases

Local status and power in area-based health improvement partnerships

This is the authors' PDF version of an article published in Health© 2014. The definitive version is available at http://hea.sagepub.comArea-based initiatives (ABIs) have formed an important part of public policy towards more socio-economically deprived areas in many countries. Co-ordinating service provision within and across sectors has been a common feature of these initiatives. Despite sustained policy interest in ABIs, little empirical work has explored relations between ABI providers and partnership development within this context remains under-theorised. This paper addresses both of these gaps by exploring partnerships as a social and developmental process, drawing on concepts from figurational sociology to explain how provider relations develop within an ABI. Qualitative methods were used to explore, prospectively, the development of an ABI targeted at a town in the north west of England. A central finding was that, although effective delivery of ABIs is premised on a high level of coordination between service providers, the pattern of interdependencies between providers limits the frequency and effectiveness of cooperation. In particular, the interdependency of ABI providers with others in their organisation (what is termed here ‘organisational pull’) constrained the ways in which they worked with providers outside of their own organisations. ‘Local’ status, which could be earned over time, enabled some providers to exert greater control over the way in which provider relations developed during the course of the initiative. These findings demonstrate how historically constituted social networks, within which all providers are embedded, shape partnership development. The theoretical insight developed here suggests a need for more realistic expectations among policy makers about how and to what extent provider partnerships can be managed. Keywords: partnership, collaboration, community services, area-based initiatives, organisational pull, figurational sociologyNational Health Service (NHS

Canonical density matrix perturbation theory

Density matrix perturbation theory [Niklasson and Challacombe, Phys. Rev. Lett. 92, 193001 (2004)] is generalized to canonical (NVT) free energy ensembles in tight-binding, Hartree-Fock or Kohn-Sham density functional theory. The canonical density matrix perturbation theory can be used to calculate temperature dependent response properties from the coupled perturbed self-consistent field equations as in density functional perturbation theory. The method is well suited to take advantage of sparse matrix algebra to achieve linear scaling complexity in the computational cost as a function of system size for sufficiently large non-metallic materials and metals at high temperatures.Comment: 21 pages, 3 figure

Quality improvement of traditional dry fermented sausages based on innovative technological strategies

Dry fermented sausages are highly appreciated food specialties, mainly in Portugal and other southern European countries. Therefore, all research efforts aiming at improving the food quality and safety of traditional dry sausages are of interest, since they are likely to result in products with higher added value and quality standards most suited to the requirements and concerns of the modern consumers. Among those efforts, it may be highlighted the studies involving innovative processing parameters and technologies to overcome practical problems gathered in the meat industry, which are mostly associated with food quality and safety. Additionally, characterization of traditional dry sausages and rationalization of their processing are essential for further achievement of any official certification. Thus, this article attempts to point out some research lines of highest interest in meat science (and particularly to the broad variety of regional dry fermented sausages), towards to the valorisation of technological, nutritional and commercial features. In addition, it is here emphasized the importance for the continuous improvement of the quality and safety of meat products as a way to respond to the current concerns regarding its consumption and the general advices in reducing its daily intake

The structural invisibility of outsiders: the role of migrant labour in the meat-processing industry

This article examines the role of migrant workers in meat-processing factories in the UK. Drawing on materials from mixed methods research in a number of case study towns across Wales, we explore the structural and spatial processes that position migrant workers as outsiders. While state policy and immigration controls are often presented as a way of protecting migrant workers from work-based exploitation and ensuring jobs for British workers, our research highlights that the situation ‘on the ground’ is more complex. We argue that ‘self-exploitation’ among the migrant workforce is linked to the strategies of employers and the organisation of work, and that hyper-flexible work patterns have reinforced the spatial and social invisibilities of migrant workers in this sector. While this creates problems for migrant workers, we conclude that it is beneficial to supermarkets looking to supply consumers with the regular supply of cheap food to which they have become accustomed

Intrasheath subluxation of the peroneal tendons.

BACKGROUND: Dislocation or subluxation of the peroneal tendons out of the peroneal groove under a torn or avulsed superior peroneal retinaculum has been well described. We identified a new subgroup of patients with intrasheath subluxation of these tendons within the peroneal groove and with an otherwise intact retinaculum. METHODS: The cases of fifty-seven patients with painful snapping of the peroneal tendons posterior to the fibula were reviewed. Of these, forty-three had tendons that could be reproducibly subluxated out of the groove with a dorsiflexion-eversion maneuver of the ankle. Fourteen patients who could not subluxate the tendons out of the groove underwent a dynamic ultrasound examination of the tendons. While the same dorsiflexion and eversion maneuver was being performed, the tendons were seen to switch their relative positions (the peroneus longus came to lie deep to the peroneus brevis tendon) with a reproducible painful click. All fourteen patients underwent a peroneal groove-deepening procedure with retinacular reefing. Intraoperatively, thirteen patients were found to have a convex peroneal groove and all fourteen had an intact peroneal retinaculum. All patients subsequently underwent a follow-up dynamic ultrasound examination and an American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score evaluation at a minimum of twenty-four months after surgery. RESULTS: All fourteen patients were female, with an average age of thirty-five years. Two subtypes of intrasheath subluxation were found. Type A (ten patients) involved intact tendons with relative switching of their anatomic alignment. Type B (four patients) involved a longitudinal split within the peroneus brevis tendon through which the longus tendon subluxated. Intraoperative confirmation of the ultrasound findings was 100%. At an average follow-up interval of thirty-three months, the average AOFAS score had improved from 61 points preoperatively to 93 points, and the average score on the 10-cm visual analog pain scale had improved from 6.8 to 1.2. Follow-up ultrasound evaluation revealed healed tendons without persistent subluxation in thirteen patients. Nine patients rated the result as excellent, four rated it as good, and one rated it as fair. CONCLUSIONS: Patients with retrofibular pain and clicking of the peroneal tendons may not have demonstrable subluxation on physical examination and may have an intact superior peroneal retinaculum. They may have an intrasheath subluxation of the peroneal tendons, which can be confirmed with use of a dynamic ultrasound. Surgical repair of tendon tears combined with a peroneal groove-deepening procedure with retinacular reefing is a reproducibly effective procedure for this condition

Engaging local communities in social learning for inclusive management of native fruit trees in the Central Western Ghats, India

Participatory research and the social learning it supports are increasingly being used to improve forest management. Yet, the participation of women and other marginalized groups is often limited in these processes. This is a serious shortcoming, not only due to concerns for gender and social equity, but also because socially excluded, forest-dependent groups hold specific ecological knowledge, skills and interests that influence prospects for sustainable forest management. Carried out in India’s Central Western Ghats, this study explores the potential participatory research holds for engaging communities in a socially inclusive learning process that can support forest management. Participatory tools – resource mapping, Four Cell Analysis, seasonal fruit calendar, and seasonal activity – were used to elicit information on native fruit tree diversity, phenology, agronomy, uses and marketing. We discuss the benefits of this research set-up which promoted interactions among individuals from different groups, who came to experience a common group identity. The notion of contact zones – where different cultures or groups meet and engage with each other in ways that can reduce conflicts or redress asymmetrical power relations – guides our analysis. We demonstrate that the contact zone created through research process facilitated multi-directional information sharing and supported collective actions for forest management

Personal goals, group performance and ‘social’ networks: participants’ negotiation of virtual and embodied relationships in the ‘Workplace Challenge’ physical activity programme

County Sports Partnerships (CSPs) epitomise the growing reliance upon building networks and partnerships sports delivery. This study investigated how social networks were created and contested in a CSP-led programme entitled the ‘Workplace Challenge’ (WPC). The WPC used a web-platform to encourage workplace-based teams to engage in physical activity by self-recording their activity over an eight-week period. Points were awarded for activity completed and a peer-challenge facility was promoted via online league tables, prizes and the opportunity to ‘challenge’ other users. Semi-structured interviews were conducted with a total of seventeen participants recruited from one public and one private sector workplace and from a sample of participants registered as individuals. Two programme planners employed by the CSP also took part. A figurational framework was utilised to investigate participants’ negotiation of networks of embodied and virtual relationships within the programme. Findings suggest the messages promoted in the WPC were disseminated and transformed according to the organizational structure of these networks. Embodied social relationships within workplaces reinforced peer support in professional I-we identities, whereas virtual networks sometimes highlighted participants’ isolation. Moreover, emphasis upon competition within and between teams caused some to question their performance. Often, competition motivated engagement. For less active participants, constant comparison could prove discouraging, particularly if participants felt they had let their colleagues down. Planners of similar programmes must be cognizant of the uneven manner of programme dissemination. Contextual differences at the point of delivery including existing organizational structures and power hierarchies have an impact upon participants’ perceptions of a programme