1,648 research outputs found
Two-dimensional chiral crystals in the NJL model
We investigate the phase structure of the Nambu--Jona-Lasinio model at zero
temperature, allowing for a two-dimensional spatial dependence of the chiral
condensate. Applying the mean-field approximation, we consider various periodic
structures with rectangular and hexagonal geometries, and minimize the
corresponding free energy. We find that these two-dimensional chiral crystals
are favored over homogeneous phases in a certain window in the region where the
phase transition would take place when the analysis was restricted to
homogeneous condensates. It turns out, however, that in this regime they are
disfavored against a phase with a one-dimensional modulation of the chiral
condensate. On the other hand, we find that square and hexagonal lattices
eventually get favored at higher chemical potentials. Although stretching the
limits of the model to some extent, this would support predictions from
quarkyonic-matter studies.Comment: 12 pages, 6 figures. v2: added figure, small modifications, matches
published versio
Ultra high bypass Nacelle aerodynamics inlet flow-through high angle of attack distortion test
A flow-through inlet test program was conducted to evaluate inlet test methods and determine the impact of the fan on inlet separation when operating at large angles of attack. A total of 16 model configurations of approximately 1/6 scale were tested. A comparison of these flow-through results with powered data indicates the presence of the fan increased separation operation 3 degrees to 4 degrees over the flow through inlet. Rods and screens located at the fan face station, that redistribute the flow, achieved simulation of the powered-fan results for separation angle of attack. Concepts to reduce inlet distortion and increase angle of attack capability were also evaluated. Vortex generators located on the inlet surface increased inlet angle of attack capability up to 2 degrees and reduced inlet distortion in the separated region. Finally, a method of simulating the fan/inlet aerodynamic interaction using blockage sizing method has been defined. With this method, a static blockage device used with a flow-through model will approximate the same inlet onset of separation angle of attack and distortion pattern that would be obtained with an inlet model containing a powered fan
A Stochastic Game Theoretical Model for Cyber Security
The resiliency of systems integrated through cyber networks is of utmost importance due to the reliance on these systems for critical services such as industrial control systems, nuclear production, and military weapons systems. Current research in cyber resiliency remains largely limited to methodologies utilizing a singular technique that is predominantly theoretical with limited examples given. This research uses notional data in presenting a novel approach to cyber system analysis and network resource allocation by leveraging multiple techniques including game theory, stochastic processes, and mathematical programming. An operational network security problem consisting of 20 tactical normal form games provides an assessment of the resiliency of a cyber defender\u27s network by leveraging the solutions of each tactical game to inform transitional probabilities of a discrete-time Markov chain over an attacker- defender state space. Furthermore, the Markov chain provides an assessment of the conditional path through the operational problem with an expected cost of damage to the defender network. The solutions of the tactical games and, in turn the operational problem, are utilized to determine the effects and risks of projected network improvement resource allocation decisions via an integer program. These results can be used to inform network analysts of the resiliency of their network while providing recommendations and requirements for improving their network resiliency posture against potential malicious external actors
Optimal Rebuilding of Fish Stocks in Different Nations: Bioeconomic Lessons for Regulators
Under the rubric of sustainable fisheries, nations are mandated to rebuild overfished stocks. Although rebuilding strategies are almost universally directed by the available biological information, approaches vary depending on fishery laws, management objectives, and technical guidelines. For example, rebuilding schedules in the United States are primarily designed to achieve rapid rebuilding of biomass and spawning stocks consistent with the biological characteristics of the resource. In contrast, New Zealand has greater flexibility in rebuilding stocks in order to consider economic, social, and cultural needs. In this paper we investigate potential economic costs to the fishery that result by limiting the US manager’s flexibility in choosing a recovery trajectory. Using numerical models for moderate- and long-lived stocks, the analysis reveals that depending on productivity of the stock and the discount rate, extending the rebuilding timeframe can substantially increase annual harvests and economic benefits. The results underscore the importance of economic analysis in crafting flexible rebuilding schedules that account for the unique characteristics of the fisheries, including economic and social needs.Fisheries economics, fisheries management, K-selective species, rebuilding., Resource /Energy Economics and Policy, Q22, C61,
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Including Family Carers: Adding Value and Impact to Research
As family carers we are not a homongeneous group but come in all shapes and sizes, and play an invaluable role in society. We have a variety of experiences, and expertise in the needs of the person or people we care for or have cared for as well as our own experiences of being carers. Across the diverse group of carers and caring situations, we each have our own individual voice which may differ from that of the person we care for.
Yet, in research studies our voices are sometimes excluded or only sought when the cared for person is unable to give their own views. The focus on services or the cared for person can sometimes ignore the experience and expertise carers bring to an issue. Often the symbiotic nature of the caring relationship is not recognised; so when the focus is on interventions for the cared for person the resulting impact on their carers is overlooked. There is no doubt that more research is needed on the role, needs and support for carers. But ther is also no doubt that the voice of carers needs to be captured across all health and social care studies even when the focus is on the cared for person.
This report, from a workshop organised by the Independent Advisory Group on Carers and the NIHR School for Social Care Research, highlights the pivotal role carers play in the effectiveness of future health and social care-related research. Carers can be valuable partners, providing unique inputs into all stages of research design, from forming the research question to the methodology, analysis and in sharing the findings.
Our voice as carers needs to become an integral part of all health or social care-related research studies. There are actions that research funders, research teams, the health and social care sectors, and carers can take to make this happen. This report highlights some of these but it is important that actions follow. The first step is to recognise carers as a distinct, diverse and valuable group in research.
We welcome positive steps being taken to achieve the priorities set out in this report
The language and policy of care and parenting:Understanding the uncertainty about key players' roles in foster care provision
Recent debates about the care provided to looked-after children have been characterised by uncertainty about the differing roles and responsibilities of foster carers, birth parents, and social workers. To explore the assumptions underlying these uncertainties, we drew upon Foucauldian Discourse Analysis and compared the discourses used by professionals (social workers in a group discussion about foster placement breakdown) with those used by policy-makers (in the Governmental green paper 'Care Matters'). In both cases, a discourse based upon Attachment Theory was used to explain why placements succeed and fail, and to predict the repercussions of failure. However, there was a key difference in the way that professionals and policy-makers constructed the roles of key players in foster placements. The social workers constructed the birth parents as the parental figures for children in care, constructing themselves in a non-parental role. 'Care Matters' largely ignores the role of birth parents, and instead constructs social workers as parental figures. Neither source viewed foster carers as parental and 'Care Matters' positions this group as strictly professional. We discuss the incongruence of foster placements being understood through Attachment Theory, while foster carers are understood as non-parental figures, and also the repercussions of labelling a social worker as a parent, and the professionalization of the role of the foster carer
Using experience-based co-design to improve inpatient mental health spaces
Inpatient services are frequently constructed as a topic of concern in research and policy, often in response to service-users’ reports that wards are unsafe, boring, and lacking in amenities (Quirk & Lelliott, 2001). Our research shows that service-users, as well as staff and families, experience inpatient mental health spaces as impermeable, separate and stigmatising, and sometimes uncomfortable, chaotic and unsafe (Fenton et al., 2014; Hickman et al., 2015). Experience-based co-design (EBCD; Bate & Robert, 2007) is a participatory action research approach to service development, which has been used extensively in physical healthcare (Donetto, Tsianakas & Robert, 2014), but is only recently being used to improve mental health services (Larkin, Boden & Newton, 2014). This chapter will draw on EBCD projects from two NHS Mental Health Trusts. These projects brought together service-users, staff and families, alongside Trust management and community staff to co-design improvements to the inpatient wards. Sometimes these improvements were as simple as introducing soft furnishings and better signage, sometimes they were more complex interventions in the culture of the wards, however all the improvements, and perhaps more importantly, the improvement process, allowed service-users and families to feel more welcomed and comforted, and helped staff working in difficult circumstances feel more supported
Mapping optical path length and image enhancement using quantitative orientation-independent differential interference contrast microscopy
Author Posting. © Society of Photo Optical Instrumentation Engineers, 2017. This article is posted here by permission of Society of Photo Optical Instrumentation Engineers for personal use, not for redistribution. The definitive version was published in Journal of Biomedical Optics 22 (2017): 016006, doi:10.1117/1.JBO.22.1.016006.We describe the principles of using orientation-independent differential interference contrast (OI-DIC) microscopy for mapping optical path length (OPL). Computation of the scalar two-dimensional OPL map is based on an experimentally received map of the OPL gradient vector field. Two methods of contrast enhancement for the OPL image, which reveal hardly visible structures and organelles, are presented. The results obtained can be used for reconstruction of a volume image. We have confirmed that a standard research grade light microscope equipped with the OI-DIC and 100×/1.3 NA objective lens, which was not specially selected for minimum wavefront and polarization aberrations, provides OPL noise level of ∼0.5 nm and lateral resolution if ∼300 nm at a wavelength of 546 nm. The new technology is the next step in the development of the DIC microscopy. It can replace standard DIC prisms on existing commercial microscope systems without modification. This will allow biological researchers that already have microscopy setups to expand the performance of their systems.This
publication was made possible by Grant No. R01-GM101701
from the National Institute of General Medical Sciences,
National Institutes of Health
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