Causality and the speed of sound

A usual causal requirement on a viable theory of matter is that the speed of sound be at most the speed of light. In view of various recent papers querying this limit, the question is revisited here. We point to various issues confronting theories that violate the usual constraint.Comment: v2: additional discussion on models that appear to have superluminal signal speeds; version to appear in GR

Walking Behaviour of Individuals with Intermittent Claudication Compared to Matched Controls in Different Locations: An Exploratory Study

Individuals with intermittent claudication (IC) are less physically active than their peers, but how this varies with location is unclear. Individuals with IC and matched controls [sex, age ±5 years, home < 5 miles] wore an activity monitor (activPAL) and carried a GPS device (AMOD-AGL3080) for 7 days. GPS data categorised walking events as occurring at home (<=50 m from home coordinates) or away from home, and indoors (signal to noise ratio <= 212 dB) or outdoors. Number of walking events, walking duration, steps and cadence were compared between groups and each location pair using mixed model ANOVAs. In addition, the locus of activity (distance from home) at which walking was conducted was compared between groups. Participants (n = 56) were mostly male (64%) and aged 54-89 years. Individuals with IC spent significantly less time walking and took fewer steps than their matched controls at all locations, including at home. Participants spent more time and took more steps away from home than at home, but were similar when walking indoors and outdoors. The locus of activity was significantly smaller for individuals with IC, suggesting that it is not just physical capacity that influences walking behaviour, and other factors (e.g., social isolation) may play a role

Non-toxic metal-cyclam complexes, a new class of compounds with potency against drug-resistant Mycobacterium tuberculosis

Tuberculosis (TB) accounted for 1.5 million deaths in 2014 and new classes of anti-TB drugs are required. We re-port a class of functionalized 1,8-disubstituted cyclam derivatives that display low micromolar activity against pathogenic myco-bacteria. These compounds inhibit intracellular growth of Mycobacterium tuberculosis, are non-toxic to human cell lines and are active against multidrug-resistant M. tuberculosis strains, indicating a distinct mode of action. These compounds warrant further appraisal as novel agents to control TB in humans.This work was supported by the National Health and Medical Research Council (NHMRC) Project APP1084266, the NHMRC Center of Research Excellence in Tuberculosis Control (APP1043225) and the University of Sydney Sydnovate Fund. We acknowledge the Centre for Drug Candidate Optimization, Monash University for the ADME studie

The inpatient burden of abdominal and gynecological adhesiolysis in the US

<p>Abstract</p> <p>Background</p> <p>Adhesions are fibrous bands of scar tissue, often a result of surgery, that form between internal organs and tissues, joining them together abnormally. Postoperative adhesions frequently occur following abdominal surgery, and are associated with a large economic burden. This study examines the inpatient burden of adhesiolysis in the United States (i.e., number and rate of events, cost, length of stay [LOS]).</p> <p>Methods</p> <p>Hospital discharge data for patients with primary and secondary adhesiolysis were analyzed using the 2005 Healthcare Cost and Utilization Project's Nationwide Inpatient Sample. Procedures were aggregated by body system.</p> <p>Results</p> <p>We identified 351,777 adhesiolysis-related hospitalizations: 23.2% for primary and 76.8% for secondary adhesiolysis. The average LOS was 7.8 days for primary adhesiolysis. We found that 967,332 days of care were attributed to adhesiolysis-related procedures, with inpatient expenditures totaling $2.3 billion ($1.4 billion for primary adhesiolysis; $926 million for secondary adhesiolysis). Hospitalizations for adhesiolysis increased steadily by age and were higher for women. Of secondary adhesiolysis procedures, 46.3$220 million in attributable costs.</p> <p>Conclusions</p> <p>Adhesiolysis remain an important surgical problem in the United States. Hospitalization for this condition leads to high direct surgical costs, which should be of interest to providers and payers.</p

A national-scale assessment of climate change impacts on species: assessing the balance of risks and opportunities for multiple taxa

It is important for conservationists to be able to assess the risks that climate change poses to species, in order to inform decision making. Using standardised and repeatable methods, we present a national-scale assessment of the risks of range loss and opportunities for range expansion, that climate change could pose for over 3,000 plants and animals that occur in England. A basic risk assessment that compared projected future changes in potential range with recently observed changes classified 21% of species as being at high risk and 6% at medium risk of range loss under a B1 climate change scenario. A greater number of species were classified as having a medium (16%) or high (38%) opportunity to potentially expand their distribution. A more comprehensive assessment, incorporating additional ecological information, including potentially confounding and exacerbating factors, was applied to 402 species, of which 35 % were at risk of range loss and 42 % may expand their range extent. This study covers a temperate region with a significant proportion of species at their poleward range limit. The balance of risks and opportunities from climate change may be different elsewhere. The outcome of both risk assessments varied between taxonomic groups, with bryophytes and vascular plants containing the greatest proportion of species at risk from climate change. Upland habitats contained more species at risk than other habitats. Whilst the overall pattern was clear, confidence was generally low for individual assessments, with the exception of well-studied taxa such as birds. In response to climate change, nature conservation needs to plan for changing species distributions and increasing uncertainty of the future

The long-term effect of being treated in a geriatric ward compared to an orthopaedic ward on six measures of free-living physical behavior 4 and 12 months after a hip fracture - a randomised controlled trial

Background This study is part of the Trondheim Hip Fracture Trial, where we compared free-living physical behavior in daily life 4 and 12 months following hip surgery for patients managed with comprehensive geriatric care (CGC) in a geriatric ward with those managed with orthopedic care (OC) in an orthopedic ward. Methods This is a single centre, prospective, randomized controlled trial. 397 hip fracture patients were randomized to CGC (n = 199) or OC (n = 198) in the Emergency Department with follow-up assessments performed four and 12 months post-surgery. Outcomes were mean upright time, number and length of upright events recorded continuously for four days at four and 12 months post-surgery by an accelerometer-based activity monitor. Missing data were handled by multiple imputation and group differences assessed by linear regression with adjustments for gender, age and fracture type. Results There were no group differences in participants’ pre-fracture characteristics. Estimated group difference in favor of CGC in upright time at 4 months was 34.6 min (17.4 %, CI 9.6 to 59.6, p = .007) and at 12 months, 27.7 min (13.9 %, CI 3.5 to 51.8, p = .025). Average and maximum length of upright events was longer in the CGC (p’s &lt; .042). No group difference was found for number of upright events (p’s &gt; .452). Conclusion Participants treated with CGC during the hospital stay improved free-living physical behavior more than those treated with OC both 4 and 12 months after surgery, with more time and longer periods spent in upright. Results support findings from the same study for functional outcomes, and demonstrate that CGC impacts daily life as long as one year after surgery

Protocol for a home-based integrated physical therapy program to reduce falls and improve mobility in people with Parkinson’s disease

Background The high incidence of falls associated with Parkinson&rsquo;s disease (PD) increases the risk of injuries and immobility and compromises quality of life. Although falls education and strengthening programs have shown some benefit in healthy older people, the ability of physical therapy interventions in home settings to reduce falls and improve mobility in people with Parkinson&rsquo;s has not been convincingly demonstrated.Methods/design 180 community living people with PD will be randomly allocated to receive either a home-based integrated rehabilitation program (progressive resistance strength training, movement strategy training and falls education) or a home-based life skills program (control intervention). Both programs comprise one hour of treatment and one hour of structured homework per week over six weeks of home therapy. Blinded assessments occurring before therapy commences, the week after completion of therapy and 12 months following intervention will establish both the immediate and long-term benefits of home-based rehabilitation. The number of falls, number of repeat falls, falls rate and time to first fall will be the primary measures used to quantify outcome. The economic costs associated with injurious falls, and the costs of running the integrated rehabilitation program from a health system perspective will be established. The effects of intervention on motor and global disability and on quality of life will also be examined. Discussion This study will provide new evidence on the outcomes and cost effectiveness of home-based movement rehabilitation programs for people living with PD

Biobanking and consenting to research: a qualitative thematic analysis of young people’s perspectives in the North East of England

Background: Biobanking biospecimens and consent are common practice in paediatric research. We need to explore children and young people’s (CYP) knowledge and perspectives around the use of and consent to biobanking. This will ensure meaningful informed consent can be obtained and improve current consent procedures. Methods: We designed a survey, in co-production with CYP, collecting demographic data, views on biobanking, and consent using three scenarios: 1) prospective consent, 2) deferred consent, and 3) reconsent and assent at age of capacity. The survey was disseminated via the Young Person’s Advisory Group North England (YPAGne) and participating CYP’s secondary schools. Data were analysed using a qualitative thematic approach by three independent reviewers (including CYP) to identify common themes. Data triangulation occurred independently by a fourth reviewer. Results: One hundred two CYP completed the survey. Most were between 16–18 years (63.7%, N = 65) and female (66.7%, N = 68). 72.3% had no prior knowledge of biobanking (N = 73). Acceptability of prospective consent for biobanking was high (91.2%, N = 93) with common themes: ‘altruism’, ‘potential benefits outweigh individual risk’, 'frugality', and ‘(in)convenience’. Deferred consent was also deemed acceptable in the large majority (84.3%, N = 86), with common themes: ‘altruism’, ‘body integrity’ and ‘sample frugality’. 76.5% preferred to reconsent when cognitively mature enough to give assent (N = 78), even if parental consent was previously in place. 79.2% wanted to be informed if their biobanked biospecimen is reused (N = 80). Conclusion: Prospective and deferred consent acceptability for biobanking is high among CYP in the UK. Altruism, frugality, body integrity, and privacy are the most important themes. Clear communication and justification are paramount to obtain consent. Any CYP with capacity should be part of the consenting procedure, if possible

Rho GTPase function in flies: insights from a developmental and organismal perspective.

Morphogenesis is a key event in the development of a multicellular organism and is reliant on coordinated transcriptional and signal transduction events. To establish the segmented body plan that underlies much of metazoan development, individual cells and groups of cells must respond to exogenous signals with complex movements and shape changes. One class of proteins that plays a pivotal role in the interpretation of extracellular cues into cellular behavior is the Rho family of small GTPases. These molecular switches are essential components of a growing number of signaling pathways, many of which regulate actin cytoskeletal remodeling. Much of our understanding of Rho biology has come from work done in cell culture. More recently, the fruit fly Drosophila melanogaster has emerged as an excellent genetic system for the study of these proteins in a developmental and organismal context. Studies in flies have greatly enhanced our understanding of pathways involving Rho GTPases and their roles in development

The North American tree-ring fire-scar network

Fire regimes in North American forests are diverse and modern fire records are often too short to capture important patterns, trends, feedbacks, and drivers of variability. Tree-ring fire scars provide valuable perspectives on fire regimes, including centuries-long records of fire year, season, frequency, severity, and size. Here, we introduce the newly compiled North American tree-ring fire-scar network (NAFSN), which contains 2562 sites, >37,000 fire-scarred trees, and covers large parts of North America. We investigate the NAFSN in terms of geography, sample depth, vegetation, topography, climate, and human land use. Fire scars are found in most ecoregions, from boreal forests in northern Alaska and Canada to subtropical forests in southern Florida and Mexico. The network includes 91 tree species, but is dominated by gymnosperms in the genus Pinus. Fire scars are found from sea level to >4000-m elevation and across a range of topographic settings that vary by ecoregion. Multiple regions are densely sampled (e.g., >1000 fire-scarred trees), enabling new spatial analyses such as reconstructions of area burned. To demonstrate the potential of the network, we compared the climate space of the NAFSN to those of modern fires and forests; the NAFSN spans a climate space largely representative of the forested areas in North America, with notable gaps in warmer tropical climates. Modern fires are burning in similar climate spaces as historical fires, but disproportionately in warmer regions compared to the historical record, possibly related to under-sampling of warm subtropical forests or supporting observations of changing fire regimes. The historical influence of Indigenous and non-Indigenous human land use on fire regimes varies in space and time. A 20th century fire deficit associated with human activities is evident in many regions, yet fire regimes characterized by frequent surface fires are still active in some areas (e.g., Mexico and the southeastern United States). These analyses provide a foundation and framework for future studies using the hundreds of thousands of annually- to sub-annually-resolved tree-ring records of fire spanning centuries, which will further advance our understanding of the interactions among fire, climate, topography, vegetation, and humans across North America