795 research outputs found
Recruitment and retention of farm owners and workers for a six-month prospective injury study in New Zealand: a feasibility study
<p>Abstract</p> <p>Background</p> <p>Agricultural workers experience high rates of occupational injury. There is a lack of analytic studies which provide detailed occupational exposure information to inform intervention development.</p> <p>Methods</p> <p>A feasibility study simulating a six month prospective cohort study was designed and undertaken. The levels of farm and worker participation and retention were analysed to determine the feasibility of the methods for wider deployment.</p> <p>Results</p> <p>Recruitment levels were comparable with other studies, with 24% of farms and 36% of non-owner workers participating. Once recruited, retention was high at 85% and 86% respectively.</p> <p>Conclusions</p> <p>The main challenges identified were in the recruitment process. Once recruited, farms and workers tended to complete the study, indicating that prospective studies in this the agricultural workforce may be feasible. Issues encountered and potential solutions for future studies are discussed.</p
Toxin-mediated competition in weakly motile bacteria
Many bacterial species produce toxins that inhibit their competitors. We
model this phenomenon by extending classic two-species Lotka-Volterra
competition in one spatial dimension to incorporate toxin production by one
species. Considering solutions comprising two adjacent single-species colonies,
we show how the toxin inhibits the susceptible species near the interface
between the two colonies. Moreover, a sufficiently effective toxin inhibits the
susceptible species to such a degree that an `inhibition zone' is formed
separating the two colonies. In the special case of truly non-motile bacteria,
i.e. with zero bacterial diffusivity, we derive analytical expressions
describing the bacterial distributions and size of the inhibition zone. In the
more general case of weakly motile bacteria, i.e. small bacterial diffusivity,
these two-colony solutions become travelling waves. We employ numerical methods
to show that the wavespeed is dependent upon both interspecific competition and
toxin strength; precisely which colony expands at the expense of the other
depends upon the choice of parameter values. In particular, a sufficiently
effective toxin allows the producer to expand at the expense of the
susceptible, with a wavespeed magnitude that is bounded above as the toxin
strength increases. This asymptotic wavespeed is independent of interspecific
competition and due to the formation of the inhibition zone; when the colonies
are thus separated, there is no longer direct competition between the two
species and the producer can invade effectively unimpeded by its competitor. We
note that the minimum toxin strength required to produce an inhibition zone
increases rapidly with increasing bacterial diffusivity, suggesting that even
moderately motile bacteria must produce very strong toxins if they are to
benefit in this way
Report on Midden Exposed by Coastal Erosion in Lapakahi State Historical Park, North Kohala District, Hawaiâi Island
Climate change is impacting coastal sites at an alarming rate.We report on coastal midden exposed by storm damage in the archaeological interpretive area of Lapakahi State Historical Park, North Kohala District, Hawaiâi Island, specifically, Site 50-10-02-04043, a canoe shed (halau). Site 04043 was first recorded, but not excavated, in the 1970s. Radiocarbon dating reported here suggests deposits did not begin accumulating until ca. cal AD 1700â1900, surprisingly late given its coastal location and previous dating of leeward Kohala sites. To help understand this we considered how the coastline has changed over time. We estimate, based on high-resolution airborne LiDAR bathometry, that this location was around 100m inland at the time people first arrived in the Hawaiian Islands. The subsidence of Hawaiâi Island slowly brought the coastline closer and it would have been around 10m from this location when deposits began accumulating. The contents of the midden are consistent with previous studies of subsistence in leeward Kohala.We attempted to improve on the specificity of the faunal inventory through ancient DNA but failed to recover intact DNA in fragmentary faunal bone samples. We note that reporting negative results is important for the judicious use of this technique. In sum, our results highlight the critical importance of a targeted, systematic study of early settlementâsomething that has never been done in the Hawaiian Islandsârather than relying on the type of salvage excavations described here
Spatial and temporal analysis of extreme sea level and storm surge events around the coastline of the UK
In this paper we analyse the spatial footprint and temporal clustering of extreme sea level and skew surge events around the UK coast over the last 100 years (1915-2014). The vast majority of the extreme sea level events are generated by moderate, rather than extreme skew surges, combined with spring astronomical high tides. We distinguish four broad categories of spatial footprints of events and the distinct storm tracks that generated them. There have been rare events when extreme levels have occurred along two unconnected coastal regions during the same storm. The events that occur in closest succession (< 4 days) typically impact different stretches of coastline. The spring/neap tidal cycle prevents successive extreme sea level events from happening within 4-8 days. Finally, the 2013/14 season was highly unusual in the context of the last 100 years from an extreme sea level perspective
A user-friendly database of coastal flooding in the United Kingdom from 1915â2014
Coastal flooding caused by extreme sea levels can be devastating, with long-lasting and diverse consequences. Historically, the UK has suffered major flooding events, and at present 2.5 million properties and ÂŁ150 billion of assets are potentially exposed to coastal flooding. However, no formal system is in place to catalogue which storms and high sea level events progress to coastal flooding. Furthermore, information on the extent of flooding and associated damages is not systematically documented nationwide. Here we present a database and online tool called âSurgeWatchâ, which provides a systematic UK-wide record of high sea level and coastal flood events over the last 100 years (1915-2014). Using records from the National Tide Gauge Network, with a dataset of exceedance probabilities and meteorological fields, SurgeWatch captures information of 96 storms during this period, the highest sea levels they produced, and the occurrence and severity of coastal flooding. The data are presented to be easily assessable and understandable to a range of users including, scientists, coastal engineers, managers and planners and concerned citizens
Effects of environmental enrichment on white matter glial responses in a mouse model of chronic cerebral hypoperfusion
Background:
This study was designed to explore the beneficial effects of environmental enrichment (EE) on white matter glial changes in a mouse model of chronic cerebral hypoperfusion induced by bilateral common carotid artery stenosis (BCAS).
Methods:
A total of 74 wild-type male C57BL/6J mice underwent BCAS or sham surgery. One week after surgery, the mice were randomly assigned into three different groups having varied amounts of EEâstandard housing with no EE conditions (std), limited exposure with 3 h EE a day (3 h) and full-time exposure to EE (full) for 12 weeks. At 16 weeks after BCAS surgery, behavioural and cognitive function were assessed prior to euthanasia. Brain tissues were analysed for the degree of gliosis including morphological changes in astrocytes and microglia.
Results:
Chronic cerebral hypoperfusion (or BCAS) increased clasmatodendrocytes (damaged astrocytes) with disruption of aquaporin-4 immunoreactivity and an increased degree of microglial activation/proliferation. BCAS also impaired behavioural and cognitive function. These changes were significantly attenuated, by limited exposure compared to full-time exposure to EE.
Conclusions:
Our results suggest that moderate or limited exposure to EE substantially reduced glial damage/activation. Our findings also suggest moderate rather than continuous exposure to EE is beneficial for patients with subcortical ischaemic vascular dementia characterised by white matter disease-related inflammation
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Issues in design and interpretation of MDR-TB clinical trials: report of the first Global MDR-TB Clinical Trials Landscape Meeting
Recognizing that the current MDR-TB regimen is suboptimal and based on low-quality evidence, the Global MDR-TB Clinical Trials Landscape Meeting was held in December, 2014 to strategize about coordination of research and development of new treatment regimens for this disease that affects millions of people worldwide every year. Sixty international experts on multidrug-resistant tuberculosis (MDR-TB) met in Washington D.C. and Cape Town, South Africa to consider key MDR-TB trial-related issues, including: standardization of definitions; clinical trial capacity building and; regimens optimized to foster compliance, avoid the emergence of resistance and have clinical relevance for special populations, including children and those co-infected with HIV. Underpinning all of this is the generation of a sufficient evidence base to facilitate regulatory approval and improved normative guidance. Participants discussed treatment combinations currently being studied in Phase 2B and Phase 3 trials as well as other promising new regimens and combinations that may be evaluated in the near future. These include regimens designed specifically to enable shorter duration and all-oral treatment as a means of maximizing treatment completion. It is hoped that clear definition of these challenges will facilitate the process of identifying solutions that accelerate progress towards effective, non-toxic treatments that can be programmatically implemented
Evidence for the differential expression of a variant EGF receptor protein in human prostate cancer
Earlier studies have demonstrated an unexplained depletion of the epidermal growth factor receptor (EGFR) protein expression in prostatic cancer. We now attribute this phenomenon to the presence of a variant EGFR (EGFRvIII) that is highly expressed in malignant prostatic neoplasms. In a retrospective study, normal, benign hyperplastic and malignant prostatic tissues were examined at the mRNA and protein levels for the presence of this mutant receptor. The results demonstrated that whilst EGFRvIII was not present in normal prostatic glands, the level of expression of this variant protein increased progressively with the gradual transformation of the tissues to the malignant phenotype. The selective association of high EGFRvIII levels with the cancer phenotype underlines the role that this mutant receptor may maintain in the initiation and progression of malignant prostatic growth, and opens the way for new approaches in the management of this disease including gene therapy. © 2000 Cancer Research Campaig
A review of climate change and the implementation of marine biodiversity legislation in the United Kingdom
1. Marine legislation, the key means by which the conservation of marine biodiversity is achieved, has been developing since the 1960s. In recent decades, an increasing focus on âholisticâ policy development is evident, compared with earlier âpiecemealâ sectoral approaches. Important marine legislative tools being used in the United Kingdom, and internationally, include the designation of marine protected areas and the Marine Strategy Framework Directive (MSFD) with its aim of meeting âGood Environmental Statusâ (GES) for European seas by 2020. 2. There is growing evidence of climate change impacts on marine biodiversity, which may compromise the effectiveness of any legislation intended to promote sustainable marine resource management. 3. A review of key marine biodiversity legislation relevant to the UK shows climate change was not considered in the drafting of much early legislation. Despite the huge increase in knowledge of climate change impacts in recent decades, legislation is still limited in how it takes these impacts into account. There is scope, however, to account for climate change in implementing much of the legislation through (a) existing references to environmental variability; (b) review cycles; and (c) secondary legislation and complementary policy development. 4. For legislation relating to marine protected areas (e.g. the EC Habitats and Birds Directives), climate change has generally not been considered in the site-designation process, or for ongoing management, with the exception of the Marine (Scotland) Act. Given that changing environmental conditions (e.g. rising temperatures and ocean acidification) directly affect the habitats and species that sites are designated for, how this legislation is used to protect marine biodiversity in a changing climate requires further consideration. 5. Accounting for climate change impacts on marine biodiversity in the development and implementation of legislation is vital to enable timely, adaptive management responses. Marine modelling can play an important role in informing management decisions
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