27 research outputs found
Cosmological perturbation theory in Generalized Einstein-Aether models
We investigate the evolution of cosmological perturbations in models of dark
energy described by a time-like unit normalized vector field specified by a
general function , so-called Generalized
Einstein-Aether models. First we study the background dynamics of such models
via a designer approach in an attempt to model this theory as dark energy. We
find that only one specific form of this designer approach matches CDM
at background order and we also obtain a differential equation which
must satisfy for general CDM cosmologies. We also
present the equations of state for perturbations in Generalized Einstein-Aether
models, which completely parametrize these models at the level of linear
perturbations. A generic feature of modified gravity models is that they
introduce new degrees of freedom. By fully eliminating these we are able to
express the gauge invariant entropy perturbation and the scalar, vector, and
tensor anisotropic stresses in terms of the perturbed fluid variables and
metric perturbations only. These can then be used to study the evolution of
perturbations in the scalar, vector, and tensor sectors and we use these to
evolve the Newtonian gravitational potentials.Comment: 26 pages, 4 figures, 3 tables, submitted to PR
Gravitational wave constraints on dark sector models
We explore the constraints on dark sector models imposed by the recent
observation of coincident gravitational waves and gamma rays from a binary
neutron star merger, GW170817. Rather than focusing on specific models as has
been considered by other authors, we explore this in the context of the
equation of state approach of which the specific models are special cases.
After confirming the strong constraints found by others for Horndeski,
Einstein-Aether and massive gravity models, we discuss how it is possible to
construct models which might evade the constraints from GW170817 but still
leading to cosmologically interesting modifications to gravity. Possible
examples are ``miracle cancellations" such as in models, nonlocal models
and higher-order derivatives. The latter two rely on the dimensionless ratio of
the wave number of the observed gravitational waves to the Hubble expansion
rate being very large () which is used to suppress modifications
to the speed of gravitational waves.Comment: 10 page
THE ÄA BĂT PERIOD IN NORTHERN VIETNAM: CURRENT KNOWLEDGE AND FUTURE DIRECTIONS
This paper presents an overview of the pre-agricultural, ceramic producing, Neolithic Äa BĂșt culture in its archaeological, bioarchaeological and environmental contexts. Drawing on numerous examples from the âgrey literature,â often published solely in Vietnamese, we review the diversity of known sites and the faunal, floral, material cultural, mortuary and osteological evidence they provide regarding the structure, life histories and foodways of Äa BĂșt communities. We conclude with a discussion of possible future research directions that would improve what is known about the inhabitants of lowland northern Vietnam during this period, should appropriate new sites be discovered
Identity and community structure in Neolithic Man Bac, Northern Vietnam
FUNDING This research was supported by JSPS fund 16H02527 and Australian Research Council grant DP0774079. ACKNOWLEDGEMENTS Many people have been involved in the excavation and post-excavation work associated with Man Bac over the years. Here we wish to pay special thanks to Nguyen Kim Dung (then of the Institute of Archaeology, Hanoi) who co-directed the excavations in 2004/5 and 2007. The following were involved in either one or several ways between 2004/5 and 2007 (facilitation of land access, excavation, post-excavation analysis, and ublication): Nguyen Hann Khang and Nguyen Cao Tan (Ninh Binh Provincial Museum, Vietnam), the landowner of Man Bac Nguyen Van Sai, the Chung Village community, Peter Bellwood and Lorna Tilley (Australian National University), Nguyen Giang Hai (former Director, Institute of Archaeology, Hanoi), Nguyen Kim Thuy, Nguyen An Tuan, Vu The Long, Tran Thi Thuy Ha, Bui Thu Phuong, Ha Manh Thang, Nguyen Ngoc Quy, Vo Thanh Huong, Nguyen Chi Tan, Nguyen Thi Mai Huong (Institute of Archaeology, Hanoi), Mariko Yamagata (Okayama Science University, Japan), Ken-ichi Shidoda (National Museum of Nature and Science, Japan), Yukio Dodo (formerly of Tohoku University, Japan), Takeji Toizumi (Meiji University, Japan), Junmei Sawada (Nigata University of Health and Welfare, Japan), Mark Lipson (Harvard Medical School, USA), Anna Willis (James Cook University, Australia). Many thanks to Jeff Oliver for reading and commenting on an earlier draft.Peer reviewedPostprin
Macrophages directly contribute collagen to scar formation during zebrafish heart regeneration and mouse heart repair
Canonical roles for macrophages in mediating the fibrotic response after a heart attack include extracellular matrix turnover and activation of cardiac fibroblasts to initiate collagen deposition. Here we reveal that macrophages directly contribute collagen to the forming post-injury scar. Unbiased transcriptomics shows an upregulation of collagens in both zebrafish and mouse macrophages following heart injury. Adoptive transfer of macrophages, from either collagen-tagged zebrafish or adult mouse GFPtpz-collagen donors, enhances scar formation via cell autonomous production of collagen. In zebrafish, the majority of tagged collagen localises proximal to the injury, within the overlying epicardial region, suggesting a possible distinction between macrophage-deposited collagen and that predominantly laid-down by myofibroblasts. Macrophage-specific targeting of col4a3bpa and cognate col4a1 in zebrafish significantly reduces scarring in cryoinjured hosts. Our findings contrast with the current model of scarring, whereby collagen deposition is exclusively attributed to myofibroblasts, and implicate macrophages as direct contributors to fibrosis during heart repair
Long-Term Weekly Iron-Folic Acid and De-Worming Is Associated with Stabilised Haemoglobin and Increasing Iron Stores in Non-Pregnant Women in Vietnam
BACKGROUND: The prevalence of anaemia and iron deficiency in women remains high worldwide. WHO recommends weekly iron-folic acid supplementation where anaemia rates in non-pregnant women of reproductive age are higher than 20%. In 2006, a demonstration project consisting of weekly iron-folic acid supplementation and regular de-worming was set up in two districts in a northern province in Vietnam where anaemia and hookworm rates were 38% and 76% respectively. In 2008 the project was expanded to all districts in the province, targeting some 250,000 women. The objectives of this study were to: 1) examine changes in haemoglobin, iron stores and soil transmitted helminth infection prevalence over three years and 2) assess women's access to and compliance with the intervention. METHODS AND FINDINGS: The study was a semi-cross-sectional, semi-longitudinal panel design with a baseline survey, three impact surveys at three-, twelve- and thirty months after commencement of the intervention, and three compliance surveys after ten weeks, eighteen and thirty six months. RESULTS: After thirty months, mean haemoglobin stabilised at 130.3 g/L, an increase of 8.2 g/L from baseline, and mean serum ferritin rose from 23.9 ”g/L to 52 ”g/L. Hookworm prevalence fell from 76% to 22% over the same period. After thirty six months, 81% of the target population were receiving supplements and 87% were taking 75% or more of the supplements they received. CONCLUSIONS: Weekly iron-folic acid supplementation and regular de-worming was effective in significantly and sustainably reducing the prevalence of anaemia and soil transmitted helminth infections and high compliance rates were maintained over three years
Is it feasible and effective to provide osteopathy and acupuncture for patients with musculoskeletal problems in a GP setting? A service evaluation
<p>Abstract</p> <p>Background</p> <p>Spinal manipulation and acupuncture can be helpful in reducing the symptoms of musculoskeletal (MSK) pain. Both approaches are currently recommended by NICE as treatment options for patients with persistent low back pain. However, there has been no previous evaluation of a GP service using them together for MSK pain. The purpose of this study was to evaluate acceptability and outcomes for an osteopathy and acupuncture service (delivered by complementary therapy practitioners) for patients with MSK problems provided within a General Practice.</p> <p>Methods</p> <p>Patients were asked to complete a questionnaire before and after their course of treatment. Outcome measures included the Bournemouth Questionnaire (measuring MSK problems), EuroQoL-5D (measuring quality of life), medication use, physical activity and general well-being. Non-parametric tests were used to compare pre- and post- treatment variables. Qualitative data, regarding participants' views on the service, were collected from patients via a service survey and healthcare professionals via interviews. Qualitative data were analysed using thematic analysis.</p> <p>Results</p> <p>123 adults with MSK problems were referred into the service (79 female and 44 male, mean age 49 years). Complete patient questionnaire data sets (pre- and post- treatment) were available for 102 participants; 91 completed a service survey. All healthcare professionals involved in the service participated in interviews including all seven GPs and the administration manager at the practice, as well as the three acupuncture/osteopathy practitioners.</p> <p>Patient outcomes: comparisons between pre and post-treatment revealed a statistically significant improvement in MSK pain (p < 0.0001) and quality of life (p < 0.0001), and a statistically significant reduction in medication use (p < 0.0001). Qualitative analysis found that patients reported improvements in their MSK pain, mobility, other physical health conditions, well-being and self-management of their MSK problem.</p> <p>Acceptability of the service: overall patients and healthcare professionals were satisfied with the service and its provision within the Practice. Patients reported wanting increased appointment availability and flexibility, and more sessions. Complementary therapy practitioners reported finding the high number of referrals of chronic patients challenging, and wanting increased communication with GPs.</p> <p>Conclusions</p> <p>Provision of acupuncture and osteopathy for MSK pain is achievable in General Practice. A GP surgery can quickly adapt to incorporate complementary therapy provided key principles are followed.</p