Decoherence at zero temperature

Most discussions of decoherence in the literature consider the high-temperature regime but it is also known that, in the presence of dissipation, decoherence can occur even at zero temperature. Whereas most previous investigations all assumed initial decoupling of the quantum system and bath, we consider that the system and environment are entangled at all times. Here, we discuss decoherence for a free particle in an initial Schr\"{o}dinger cat state. Memory effects are incorporated by use of the single relaxation time model (since the oft-used Ohmic model does not give physically correct results)

Falls prevention in community care: 10 years on

Background: A million older people living in Australia receive community care services each year due to experiencing functional or mental health difficulties. This group may be at greater risk of falling than similar-aged people not receiving services. However, there is limited falls prevention research for this population. Purpose: The aim of this study was to identify the falls prevalence rates of older people from 10 Australian community care organizations and compare current falls prevention data to a study 10 years prior that utilized the same 10 organizations. This study also identified factors associated with falling for this population. Patients and methods: This is a cross-sectional descriptive study, in which 5,338 questionnaires were mailed to a random sample of community care recipients aged $65 years. Results: A total of 1,991 questionnaires were returned (37.3%), with 47.7% of respondents having fallen in the previous year, and 32.7% in the month prior to completing the questionnaire, similar to 10 years prior. Community care clients had a 50% higher falls rate than that reported for similar-aged people not receiving services, and this remained unchanged over the last 10 years. Eighty-six per cent of fallers had fallen once or twice, and 60% reported being injured. Thirty-six per cent of respondents reported not being able to get up independently, and only 27.4% of fallers were referred to a falls prevention program (significantly fewer than 10 years ago; 95% CI: 0.821–6.366, p=0.01). Balance issues (odds ratio [OR]: 2.06, 95% CI: 1.288–3.290, p=0.003) and perceived risk of falling in the future being “definite” (OR: 6.42, 95% CI: 1.890–21.808, p=0.003) or “unsure” (OR: 3.31, 95% CI: 1.144–9.544, p=0.027) were risk factors associated with falling. In contrast, individuals referred to a falls prevention intervention had a 47% reduced likelihood of having fallen (95% CI: 0.281–0.988, p=0.046). Conclusion: Community care clients should have their falls risk routinely assessed, and at-risk individuals be offered falls prevention advice and referral to fall prevention programs

MCG+00-32-16: An Irregular Galaxy Close to the Lowest Redshift Absorber on the 3C 273 Line of Sight

MCG+00-32-16 is the galaxy closest in position-velocity space to the lowest redshift Ly$\alpha$ absorber along the line-of-sight to the quasar 3C 273. Its projected separation is 204 (d/19 Mpc) kpc, where d is the distance from the Milky Way to the galaxy, and the redshift difference is only 94 km/s; HI 1225+01 is slightly closer in projected separation to the absorber, but has a greater redshift difference. We present HI synthesis array mapping and CCD photometry in B and R for MCG+00-32-16. The HI disk is rotating in such a way that the side of the galaxy closer to the sight-line to the quasar has the larger velocity difference from the absorber. The absorber may be a ``failed dwarf'' member of a poor galaxy group of which MCG+00-32-16 and HI 1225+01 are the only members to have formed stars.Comment: 14 pages, 9 figures, accepted by Astrophysical Journa

Can community care workers deliver a falls prevention exercise program? A feasibility study

Background: Almost half of older people receiving community care fall each year and this rate has not improved in the last decade. Falls prevention programs targeted at this group are uncommon, and expensively delivered by university trained allied health professionals. Purpose: To investigate the feasibility of community care workers delivering a falls prevention exercise program to older clients, at low or medium risk of falling, as part of an existing service provision. Patients and methods: Community care workers from 10 community care organizations participated in the training for, and delivery to their clients of, an 8-week evidence-based falls prevention exercise program. Community care workers included assessment staff (responsible for identifying the need for community care services through completing an assessment) and support workers (responsible for providing support in the home). Clients were surveyed anonymously at the completion of the intervention and workers participated in a semi-structured interview. Results: Twenty-five community care workers participated in the study. The falls prevention program was delivered to 29 clients, with an average age of 82.7 (SD: 8.72) years and consisting of 65.5% female. The intervention was delivered safely with no adverse events recorded, and the eligibility and assessment tools were completed by the majority of community care workers (93.1%). Assessment staff found it difficult to find time to deliver the intervention. Support workers were able to complete the intervention within their current service delivery period, with the initial assessment taking a small amount of additional time. Support workers reported enjoying the additional responsibility afforded by delivering the falls prevention program and seeing changes in their clients. The majority of clients (82%) reported enjoying the exercises, with 59% reporting that they felt it made a positive change in their health. Cl ients completed the exercises on average 4.8 (SD: 2.2) days per week. Conclusion: Community care workers who have completed appropriate training are able to deliver a falls prevention exercise program to their clients as part of their current services. Further research is required to determine whether the program reduces the rate of falls for community care clients and whether integration of a falls prevention program into an existing service is cost-effective

'Mine's a Pint of Bitter': Performativity, gender, class and representations of authenticity in real-ale tourism

Leisure choices are expressive of individual agency around the maintenance of taste, boundaries, identity and community. This research paper is part of a wider project designed to assess the social and cultural value of real ale to tourism in the north of England. This paper explores the performativity of real-ale tourism and debates about belonging in northern English real-ale communities. The research combines an ethnographic case study of a real-ale festival with semi-structured interviews with organisers and volunteers, northern English real-ale brewers and real-ale tourists visiting the festival. It is argued that real-ale tourism, despite its origins in the logic of capitalism, becomes a space where people can perform Habermasian, communicative leisure, and despite the contradictions of preferring some capitalist industries over others on the basis of their perceived smaller size and older age, real-ale fans demonstrate agency in their performativity

Conducting LaAlO\u3csub\u3e3\u3c/sub\u3e/SrTiO\u3csub\u3e3\u3c/sub\u3e Heterointerfaces on Atomically-Flat Substrates Prepared by Deionized-Water

We have investigated how the recently-developed water-leaching method for atomically-flat SrTiO3 (STO) substrates affects the transport properties of LaAlO3 (LAO) and STO heterointerfaces. Using pulsed laser deposition at identical growth conditions, we have synthesized epitaxial LAO thin-films on two different STO substrates, which are prepared by water-leaching and buffered hydrofluoric acid (BHF) etching methods. The structural, transport, and optical properties of LAO/STO heterostructures grown on water-leached substrates show the same high-quality as the samples grown on BHF-etched substrates. These results indicate that the water-leaching method can be used to grow complex oxide heterostructures with atomically well-defined heterointerfaces without safety concerns

Conducting LaAlO3/SrTiO3 heterointerfaces on atomically flat substrates prepared by deionized-water

We have investigated how the recently-developed water-leaching method for atomically-flat SrTiO3 (STO) substrates affects the transport properties of LaAlO3 (LAO) and STO heterointerfaces. Using pulsed laser deposition at identical growth conditions, we have synthesized epitaxial LAO thin-films on two different STO substrates, which are prepared by water-leaching and buffered hydrofluoric acid (BHF) etching methods. The structural, transport, and optical properties of LAO/STO heterostructures grown on water-leached substrates show the same high-quality as the samples grown on BHF-etched substrates. These results indicate that the water-leaching method can be used to grow complex oxide heterostructures with atomically well-defined heterointerfaces without safety concerns.Comment: 10 pages, 4 figure

Halocarbon ozone depletion and global warming potentials

Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on stratospheric ozone and climate. The CFCs, which do not contain an H atom, are not oxidized or photolyzed in the troposphere. These compounds are transported into the stratosphere where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen atom in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on stratospheric ozone and global climate (through 'greenhouse' global warming)

Topology of amorphous tetrahedral semiconductors on intermediate lengthscales

Using the recently-proposed ``activation-relaxation technique'' for optimizing complex structures, we develop a structural model appropriate to a-GaAs which is almost free of odd-membered rings, i.e., wrong bonds, and possesses an almost perfect coordination of four. The model is found to be superior to structures obtained from much more computer-intensive tight-binding or quantum molecular-dynamics simulations. For the elemental system a-Si, where wrong bonds do not exist, the cost in elastic energy for removing odd-membered rings is such that the traditional continuous-random network is appropriate. Our study thus provides, for the first time, direct information on the nature of intermediate-range topology in amorphous tetrahedral semiconductors.Comment: 4 pages, Latex and 2 postscript figure