1,189 research outputs found
High variability in nest site selection in a loggerhead turtle rookery, in Boa Vista Island, Cabo Verde
Among sea turtles, nest site selection is a crucial factor for hatching success and population viability. The
relocation of otherwise doomed clutches to safe hatcheries has been widely promoted as a conservation strategy,
although this may promote artificial selection of poorly adapted genotypes. In this study, we used multiyear
spatial nesting data of individual loggerhead turtles (Caretta caretta) from one of the largest Atlantic rookeries, in
Cabo Verde, across six consecutive nesting seasons (2013–2018), to identify spatial nesting patterns, assess how
individual nest site selection is influenced by female size and age, and estimate the impacts on the reproductive
output. Although females nested across the entire beach width, they preferentially nested in the middle of the
beach, avoiding to nest both close to the tideline and close to the vegetation line. Hatching success decreased
towards the waterline, while the risk of nest inundation or predation was high, regardless of nest location. In
general, females showed high variability in nest site selection, except larger females (> 93 cm curved carapace
length) that showed higher repeatability (r = 0.50, SE = 0.14, 95% CI: 0.16–0.72) in distances to the vegetation.
We therefore suggest that the relocation of doomed clutches should be considered for this endangered rookery, as
clutch relocation should not substantially distort the gene pool, assuming nest choice is a heritable trait. In
addition, we recommend the preservation of beach vegetation, particularly in areas with human developmet.info:eu-repo/semantics/publishedVersio
Risk assessment of wildlife-watching tourism in an important endangered loggerhead turtle rookery
T: Wildlife-watching tourism is a non-exploitative activity that can contribute to sustainable economic development of coastal communities. However, it is important to assess the potential
impact and implement best practices to mitigate any negative effects of such tourism. We studied
this issue on Boa Vista (Cabo Verde), which supports around 60% of nesting activity of one of the
most endangered loggerhead turtle rookeries globally. Between 2013 and 2016, authorized turtle
watching involved 4942 tourists, generating a mean annual direct income of >USD 289 000 and the
direct creation of >250 jobs. On JoĂŁo Barrosa beach, which supports around 20% of nests and 48%
of turtle-watching activity on the island, we tested the influence of turtle watching on nesting behavior, reproduction and nest-site fidelity. Nesting females observed by tourists spent significantly
less time on nest-camouflaging behavior, although all other phases of nesting were unaffected.
There were no statistically significant differences between the re-nesting frequency of females
watched (n = 187) and non-watched (n = 972) by tourists. We found no evidence that the current turtle-watching intensity has an effect on turtle reproduction. Turtle poaching remains a severe threat
on beaches with no turtle watching, although it has strongly decreased on beaches with tourist
visits. We suggest tour guides follow best practice guidelines to minimize disturbance, specifically
retreating from the immediate vicinity of a female during nest camouflaging to mitigate the observed impact.Peer reviewe
Reducing the Environmental Impacts of Garments through Industrially Scalable Closed-Loop Recycling: Life Cycle Assessment of a Recycled Wool Blend Sweater
Wool recycling has been practiced commercially for more than 200 years. This study used data from established, commercial processes with the aim of determining the environmental impacts of a recycled wool blend garment and the contribution of recycling to reducing impacts on the market for wool sweaters, in comparison to other emission reduction approaches relating to garment use. A cradle-to-grave life cycle assessment showed impacts of 0.05 kg CO2-e, 0.63 MJ, 0.58 L H2O-e and 0.95 L per wear of a recycled wool blend sweater for climate change, fossil energy demand, water stress and freshwater consumption, respectively. Impacts predominantly arose from garment manufacturing and consumer practices (retail and garment care). When a recycled wool blend sweater was maintained with best practice garment use and care, impacts were reduced by 66–90% relative to standard maintenance of a virgin pure wool sweater. Increasing the closed-loop recycling rate to 50% had the potential to reduce impacts for the wool sweater market 7–24%, depending on the impact category. Brands and consumers hold the key to increasing recycling rates and reducing environmental impacts via increased donation of garments for recycling and increased adoption of garments containing recycled wool
Population dynamics of a commercially harvested, non-native bivalve in an area protected for shorebirds: Ruditapes philippinarum in Poole Harbour, UK
The Manila clam Ruditapes philippinarum is one of the most commercially valuable bivalve species worldwide and its range is expanding, facilitated by aquaculture and fishing activities. In existing and new systems, the species may become commercially and ecologically important, supporting both local fishing activities and populations of shorebird predators of conservation importance. This study assessed potential fishing effects and population dynamics of R. philippinarum in Poole Harbour, a marine protected area on the south coast of the UK, where the species is important for oystercatcher Haematopus ostralegus as well as local fishers. Sampling was undertaken across three sites of different fishing intensities before and after the 2015 fishing season, which extends into the key overwintering period for shorebird populations. Significant differences in density, size and condition index are evident between sites, with the heavily dredged site supporting clams of poorer condition. Across the dredge season, clam densities in the heavily fished area were significantly reduced, with a harvesting efficiency of legally harvestable clams of up to 95% in this area. Despite occurring at significantly higher densities and growing faster under heavy fishing pressure, lower biomass and condition index of R. philippinarum in this area, coupled with the dramatic reduction in densities across the fishing season, may be of concern to managers who must consider the wider ecological interactions of harvesting with the interest of nature conservation and site integrity
Impacts of a novel shellfishing gear on macrobenthos in a marine protected area: pump-scoop dredging in Poole Harbour, UK
Understanding the impact of bottom-fishing gears at various scales and intensities on habitats and species is necessary to inform management. In Poole Harbour, UK, a multiple use marine protected area, fishermen utilise a unique ̋“pump-scoop” dredge to harvest the introduced Manila clam Ruditapes philippinarum. Managers need to balance the socio-economic benefits of the fishery with ecological concerns across the region, which has required a revision of by-laws that include both spatial and temporal measures. Within an operational fishery, we used a Before-After-Control-Impact sampling design to assess the impacts of pump-scoop dredging on benthic physical characteristics and community structure in an area where there was no dredging, an area newly opened to dredging and an area subject to high levels of historic dredging. A sampling grid was used in each area to best capture any fishing effort in the newly opened area. Core samples were taken to a depth of 30 cm within intertidal mudflats. A significant loss of fine sediments was observed in the site subject to high intensity dredging and a significant change in community structure also occurred in both dredged sites throughout the study period. In the newly opened site this was characterised by a relative increase in species richness, including increased abundance of annelid worms, notably Hediste diversicolor and Aphelochaeta marioni and a decline in the abundance of the bivalve mollusc Abra tenuis. These changes, albeit relatively small, are attributed to physical disturbance as a direct result of pump-scoop dredging, although no difference in the classification of the biotope of the site was observed. This is of particular interest to managers monitoring site condition within areas under the new by-laws as the Manila clam is spreading to other protected estuaries in the region
Hall Normalization Constants for the Bures Volumes of the n-State Quantum Systems
We report the results of certain integrations of quantum-theoretic interest,
relying, in this regard, upon recently developed parameterizations of Boya et
al of the n x n density matrices, in terms of squared components of the unit
(n-1)-sphere and the n x n unitary matrices. Firstly, we express the normalized
volume elements of the Bures (minimal monotone) metric for n = 2 and 3,
obtaining thereby "Bures prior probability distributions" over the two- and
three-state systems. Then, as an essential first step in extending these
results to n > 3, we determine that the "Hall normalization constant" (C_{n})
for the marginal Bures prior probability distribution over the
(n-1)-dimensional simplex of the n eigenvalues of the n x n density matrices
is, for n = 4, equal to 71680/pi^2. Since we also find that C_{3} = 35/pi, it
follows that C_{4} is simply equal to 2^{11} C_{3}/pi. (C_{2} itself is known
to equal 2/pi.) The constant C_{5} is also found. It too is associated with a
remarkably simple decompositon, involving the product of the eight consecutive
prime numbers from 2 to 23.
We also preliminarily investigate several cases, n > 5, with the use of
quasi-Monte Carlo integration. We hope that the various analyses reported will
prove useful in deriving a general formula (which evidence suggests will
involve the Bernoulli numbers) for the Hall normalization constant for
arbitrary n. This would have diverse applications, including quantum inference
and universal quantum coding.Comment: 14 pages, LaTeX, 6 postscript figures. Revised version to appear in
J. Phys. A. We make a few slight changes from the previous version, but also
add a subsection (III G) in which several variations of the basic problem are
newly studied. Rather strong evidence is adduced that the Hall constants are
related to partial sums of denominators of the even-indexed Bernoulli
numbers, although a general formula is still lackin
Impact of shortened crop rotation of oilseed rape on soil and rhizosphere microbial diversity in relation to yield decline
Oilseed rape (OSR) grown in monoculture shows a decline in yield relative to virgin OSR of up to 25%, but the mechanisms responsible are unknown. A long term field experiment of OSR grown in a range of rotations with wheat was used to determine whether shifts in fungal and bacterial populations of the rhizosphere and bulk soil were associated with the development of OSR yield decline. The communities of fungi and bacteria in the rhizosphere and bulk soil from the field experiment were profiled using terminal restriction fragment length polymorphism (TRFLP) and sequencing of cloned internal transcribed spacer regions and 16S rRNA genes, respectively. OSR cropping frequency had no effect on rhizosphere bacterial communities. However, the rhizosphere fungal communities from continuously grown OSR were significantly different to those from other rotations. This was due primarily to an increase in abundance of two fungi which showed 100% and 95% DNA identity to the plant pathogens Olpidium brassicae and Pyrenochaeta lycopersici, respectively. Real-time PCR confirmed that there was significantly more of these fungi in the continuously grown OSR than the other rotations. These two fungi were isolated from the field and used to inoculate OSR and Brassica oleracea grown under controlled conditions in a glasshouse to determine their effect on yield. At high doses, Olpidium brassicae reduced top growth and root biomass in seedlings and reduced branching and subsequent pod and seed production. Pyrenochaeta sp. formed lesions on the roots of seedlings, and at high doses delayed flowering and had a negative impact on seed quantity and quality
Who uses firearms as a means of suicide? A population study exploring firearm accessibility and method choice
<p>Abstract</p> <p>Background</p> <p>The 1996 Australian National Firearms Agreement introduced strict access limitations. However, reports on the effectiveness of the new legislation are conflicting. This study, accessing all cases of suicide 1997-2004, explores factors which may impact on the choice of firearms as a suicide method, including current licence possession and previous history of legal access.</p> <p>Methods</p> <p>Detailed information on all Queensland suicides (1997-2004) was obtained from the Queensland Suicide Register, with additional details of firearm licence history accessed from the Firearm Registry (Queensland Police Service). Cases were compared against licence history and method choice (firearms or other method). Odds ratios (OR) assessed the risk of firearms suicide and suicide by any method against licence history. A logistic regression was undertaken identifying factors significant in those most likely to use firearms in suicide.</p> <p>Results</p> <p>The rate of suicide using firearms in those with a current license (10.92 per 100,000) far exceeded the rate in those with no license history (1.03 per 100,000). Those with a license history had a far higher rate of suicide (30.41 per 100,000) compared to that of all suicides (15.39 per 100,000). Additionally, a history of firearms licence (current or present) was found to more than double the risk of suicide by any means (OR = 2.09, <it>P </it>< 0.001). The group with the highest risk of selecting firearms to suicide were older males from rural locations.</p> <p>Conclusion</p> <p>Accessibility and familiarity with firearms represent critical elements in determining the choice of method. Further licensing restrictions and the implementation of more stringent secure storage requirements are likely to reduce the overall familiarity with firearms in the community and contribute to reductions in rates of suicide.</p
3D imaging of colorectal cancer organoids identifies responses to Tankyrase inhibitors
Aberrant activation of the Wnt signalling pathway is required for tumour initiation and survival in the majority of colorectal cancers. The development of inhibitors of Wnt signalling has been the focus of multiple drug discovery programs targeting colorectal cancer and other malignancies associated with aberrant pathway activation. However, progression of new clinical entities targeting the Wnt pathway has been slow. One challenge lies with the limited predictive power of 2D cancer cell lines because they fail to fully recapitulate intratumoural phenotypic heterogeneity. In particular, the relationship between 2D cancer cell biology and cancer stem cell function is poorly understood. By contrast, 3D tumour organoids provide a platform in which complex cell-cell interactions can be studied. However, complex 3D models provide a challenging platform for the quantitative analysis of drug responses of therapies that have differential effects on tumour cell subpopulations. Here, we generated tumour organoids from colorectal cancer patients and tested their responses to inhibitors of Tankyrase (TNKSi) which are known to modulate Wnt signalling. Using compounds with 3 orders of magnitude difference in cellular mechanistic potency together with image-based assays, we demonstrate that morphometric analyses can capture subtle alterations in organoid responses to Wnt inhibitors that are consistent with activity against a cancer stem cell subpopulation. Overall our study highlights the value of phenotypic readouts as a quantitative method to asses drug-induced effects in a relevant preclinical model
XELOX vs FOLFOX-4 as first-line therapy for metastatic colorectal cancer: NO16966 updated results
BACKGROUND: We report updated overall survival (OS) data from study NO16966, which compared capecitabine plus oxaliplatin (XELOX) vs 5-fluorouracil/folinic acid plus oxaliplatin (FOLFOX4) as first-line therapy in metastatic colorectal cancer.
METHODS: NO16966 was a randomised, two-arm, non-inferiority, phase III comparison of XELOX vs FOLFOX4, which was subsequently amended to a 2 x 2 factorial design with further randomisation to bevacizumab or placebo. A planned follow-up exploratory analysis of OS was performed.
RESULTS: The intent-to-treat (ITT) population comprised 2034 patients (two-arm portion, n = 634; 2 x 2 factorial portion, n 1400). For the whole NO16966 study population, median OS was 19.8 months in the pooled XELOX/XELOX-placebo/XELOX-bevacizumab arms vs 19.5 months in the pooled FOLFOX4/FOLFOX4-placebo/FOLFOX4-bevacizumab arms (hazard ratio 0.95 (97.5% CI 0.85-1.06)). In the pooled XELOX/XELOX-placebo arms, median OS was 19.0 vs 18.9 months in the pooled FOLFOX4/FOLFOX4-placebo arms (hazard ratio 0.95 (97.5% CI 0.83-1.09)). FOLFOX4 was associated with more grade 3/4 neutropenia/granulocytopenia and febrile neutropenia than XELOX, and XELOX with more grade 3 diarrhoea and grade 3 hand-foot syndrome than FOLFOX4.
CONCLUSION: Updated survival data from study NO16966 show that XELOX is similar to FOLFOX4, confirming the primary analysis of progression-free survival. XELOX can be considered as a routine first-line treatment option for patients with metastatic colorectal cancer
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