858 research outputs found
Introduction: The ecological relevance of chemically induced endocrine disruption in wildlife
This article is part of the monograph “The Ecological Relevance of Chemically Induced Endocrine Disruption in Wildlife.
Can shared surfaces be safely negotiated by blind and partially sighted people?
‘Shared Space’ schemes are designed to remove the physical distinction between pedestrian space and traffic space in the street environment to encourage more pedestrians to use the area. They may also make it easier for people with wheelchairs, prams or similar to negotiate the space. However, by removing the kerbs, blind and partially sighted people lose one of the key references that they normally use to know they are in a safe space away from vehicles and to navigate around the area. This study is intended to understand what people with visual impairments need from a surface to make it clearly detectable, given that it should not be a barrier to progress for people with other mobility limitations. With this information, some surfaces were tested to determine their suitability as a delineator. Approach and/or Methodology An experimental approach was adopted. People with mobility impairments and blind and partially sighted people were recruited. All participants used the normal street environment unaccompanied. The blind and partially sighted participants included people who use a guide dog, those who use a long cane and those who use no assistive device. The people with mobility impairments all used some form of mobility aid for example walking stick or wheelchair. The tests were run in the pedestrian testing facility PAMELA at UCL. The top surface of the test facility was predominantly concrete paving slab, but with test surfaces discretely located. The task for all participants was to travel from one designated place in the test area to another. For some of these trials the participant would encounter one of the test surfaces, but on other trials they would not. After each trial the participants were asked to rate how easy it was to detect a change in surface, or how easy it was to pass over the surface. The different surfaces included blister paving, corduroy paving, a central delineator, slopes, roughened surfaces, and traditional kerb upstands of different heights. Results or Expected Results None of the 400mm wide surfaces was detected by all participants. Changes in level through slopes were considered both positively and negatively, some people asking for steeper gradients and some less steep. Kerb heights below 60mm were not reliably detectable by blind or partially sighted people and are an obstacle to people in wheelchairs. Further tests on more surfaces are in process and the results will be incorporated into this paper. Conclusion Early suggestions for detectable surfaces – proposed in UK schemes - have been either a barrier to people with mobility impairments, or difficult to detect for blind and partially sighted people or both. The work presented in this paper shows the difficulty in finding a suitable dual purpose surface, yet clarifies the design requirements for shared space delineators for people with mobility impairments and blind or partially sighted people. This work has reinforced the point that 400mm width is insufficient to be used as a tactile surface. Further conclusions will be made after the additional surface tests. Topic Code: Ca C. Accessibility concerns and solutions for those with cognitive and sensory impairment a. Pedestrian safety at crossings and intersection
Investigation of Lighting Levels for Pedestrians - Some questions about lighting levels of current lighting standards
22-23 September, 200
Integrating population biology into conservation management for endangered Nassau grouper Epinephelus striatus
This is the final version of the article. Available from the publisher via the DOI in this record.Groupers are a phylogenetically diverse group and include many ecologically and economically valuable predatory marine fishes that have experienced drastic population declines. Reproduction via spawning aggregations increases the vulnerability of grouper species such as Nassau grouper Epinephelus striatus to overfishing, and this is likely to be a major contributing factor to population declines. However, the lack of information pertaining to population structure and dynamics of Nassau grouper spawning aggregations has impeded effective ecosystem-based fisheries management for remaining stocks. Worldwide, The Bahamas has the largest number of known Nassau grouper spawning aggregations, yet very little is known about the overall status of groupers in the region. Landings of Nassau grouper in The Bahamas have declined by 86% in the last 20 years from a peak of 514 t in 1997. Available data suggest that existing management measures are failing in their attempts to prevent further declines. Effective management strategies are urgently needed that balance ecological and socioeconomic considerations to enable a sustainable Nassau grouper fishery. This review provides an analysis of the reproductive and population biology of Nassau grouper and a suggested framework to direct future research efforts for enhancing conservation management of this endangered marine fish species.Financial
support was provided to K.D.S. from the Shirley Oakes Butler
(Overseas) and (Bahamian) Charitable Trust via the
Lyford Cay Foundation and the East Nassau Rotary Club
Foundation and to C.P.D. by the Atlantis Blue Project Foundation
and a grant to the Perry Institute for Marine Science
by the Disney Conservation Fund’s Reverse The Decline
Program
The consequences of feminization in breeding groups of wild fish
EHP is a publication of the U.S. government. Publication of EHP lies in the public domain and is therefore without copyright.
Research articles from EHP may be used freely; however, articles from the News section of EHP may contain photographs or figures copyrighted by other commercial organizations and individuals that may not be used without obtaining prior approval from both the EHP editors and the holder of the copyright.
Use of any materials published in EHP should be acknowledged (for example, "Reproduced with permission from Environmental Health Perspectives") and a reference provided for the article from which the material was reproduced.BACKGROUND: The feminization of nature by endocrine-disrupting chemicals (EDCs) is a key environmental issue affecting both terrestrial and aquatic wildlife. A crucial and as yet unanswered question is whether EDCs have adverse impacts on the sustainability of wildlife populations. There is widespread concern that intersex fish are reproductively compromised, with potential population-level consequences. However, to date, only in vitro sperm quality data are available in support of this hypothesis.
OBJECTIVE: The aim of this study was to examine whether wild endocrine-disrupted fish can compete successfully in a realistic breeding scenario.
METHODS: In two competitive breeding experiments using wild roach (Rutilus rutilus), we used DNA microsatellites to assign parentage and thus determine reproductive success of the adults.
RESULTS: In both studies, the majority of intersex fish were able to breed, albeit with varying degrees of success. In the first study, where most intersex fish were only mildly feminized, body length was the only factor correlated with reproductive success. In the second study, which included a higher number of more severely intersex fish, reproductive performance was negatively correlated with severity of intersex. The intersex condition reduced reproductive performance by up to 76% for the most feminized individuals in this study, demonstrating a significant adverse effect of intersex on reproductive performance.
CONCLUSION: Feminization of male fish is likely to be an important determinant of reproductive performance in rivers where there is a high prevalence of moderately to severely feminized males.Funding for this work was derived through the Endocrine Disruption in Catchments project, which was supported by the U.K. Department for Environment Food and Rural Affairs and the U.K. Environment Agency
Development of a common carp (Cyprinus carpio) pregnane X receptor (cPXR) transactivation reporter assay and its activation by azole fungicides and pharmaceutical chemicals.
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.In mammals, the pregnane X receptor (PXR) is a transcription factor with a key role in regulating expression of several genes involved in drug biotransformation. PXR is present in fish and some genes known to be under its control can be up-regulated by mammalian PXR ligands. Despite this, direct involvement of PXR in drug biotransformation in fish has yet to be established. Here, the full length PXR sequence was cloned from carp (Cyprinus carpio) and used in a luciferase reporter assay to elucidate its role in xenobiotic metabolism in fish. A reporter assay for human PXR (hPXR) was also established to compare transactivation between human and carp (cPXR) isoforms. Rifampicin activated hPXR as expected, but not cPXR. Conversely, clotrimazole (CTZ) activated both isoforms and was more potent on cPXR, with an EC50 within the range of concentrations of CTZ measured in the aquatic environment. Responses to other azoles tested were similar between both isoforms. A range of pharmaceuticals tested either failed to activate, or were very weakly active, on the cPXR or hPXR. Overall, these results indicate that the cPXR may differ from the hPXR in its responses and/or sensitivity to induction by different environmental chemicals, with implications for risk assessment because of species differences.JC was funded by a Biotechnology and Biological Sciences Research Council Case studentship supported by AstraZeneca UK Ltd. (grant reference BB/G529332), and co-supported by the AstraZeneca Safety Health and Environment Research Program. AL was supported by grants from the Natural Environment Research Council (NE/D002818/1 and NE/E016634/1) and DEFRA awarded to CRT. Defra (UK) funded a research visit of SM to the University of Exeter under the UK-J programme. COS-7 cells were a gift from Inês Castro, University of Exeter. AstraZeneca Ltd. develops, produces, and markets a wide range of pharmaceutical agents
Historical processes and contemporary anthropogenic activities influence genetic population dynamics of Nassau grouper (Epinephelus striatus) within The Bahamas
This is the final version of the article. Available from Frontiers Media via the DOI in this record.Severe declines of endangered Nassau grouper (Epinephelus striatus) across The Bahamas and Caribbean have spurred efforts to improve their fisheries management and population conservation. The Bahamas is reported to hold the majority of fish spawning aggregations for Nassau grouper, however, the status and genetic population structure of fish within the country is largely unknown, presenting a major knowledge gap for their sustainable management. Between August 2014-February 2017, 464 individual Nassau grouper sampled from The Bahamas were genotyped using 15 polymorphic microsatellite loci to establish measures of population structure, genetic diversity and effective population size (N e ). Nassau grouper were characterized by mostly high levels of genetic diversity, but we found no evidence for geographic population structure. Microsatellite analyses revealed weak, but significant genetic differentiation of Nassau grouper throughout the Bahamian archipelago (Global FST 0.00236, p = 0.0001). Temporal analyses of changes in N e over the last 1,000 generations provide evidence in support of a pronounced historic decline in Bahamian Nassau grouper that appears to pre-date anthropogenic fishing activities. M-ratio results corroborate significant reductions in N e throughout The Bahamas, with evidence for population bottlenecks in three islands and an active fish spawning aggregation along with apparent signs of inbreeding at two islands. Current estimates of N e for Nassau grouper are considerably lower compared with historic levels. These findings represent important new contributions to our understanding of the evolutionary history, demographics and genetic connectivity of this endangered species, which are of critical importance for advancing their sustainable management.Molecular research was financially supported by the University of Exeter and research cruises were funded by the John G. Shedd Aquarium. Partial funding for KS was provided by the Shirley Oakes Butler Charitable Trust, Rotary Club of East Nassau and a private donation by I. de la Rocha
Vitellogenesis as a biomarker for estrogenic contamination of the aquatic environment
A rapidly increasing number of chemicals, or their degradation products, are being recognized as possessing estrogenic activity, albeit usually weak. We have found that effluent from sewage treatment works contains a chemical, or mixture of chemicals, that induces vitellogenin synthesis in male fish maintained in the effluent, thus indicating that the effluent is estrogenic. The effect was extremely pronounced and occurred at all sewage treatment works tested. The nature of the chemical or chemicals causing the effect is presently not known. However, we have tested a number of chemicals known to be estrogenic to mammals and have shown that they are also estrogenic to fish; that is, no species specificity was apparent. Many of these weakly estrogenic chemicals are known to be present in effluents. Further, a mixture of different estrogenic chemicals was considerably more potent than each of the chemicals when tested individually, suggesting that enhanced effects could occur when fish are exposed simultaneously to various estrogenic chemicals (as is likely to occur in rivers receiving effluent). Subsequent work should determine whether exposure to these chemicals at the concentrations present in the environment leads to any deleterious physiological effects
Molecular Mechanisms of White Spot Syndrome Virus Infection and Perspectives on Treatments.
Published onlineJournal ArticleReviewSince its emergence in the 1990s, White Spot Disease (WSD) has had major economic and societal impact in the crustacean aquaculture sector. Over the years shrimp farming alone has experienced billion dollar losses through WSD. The disease is caused by the White Spot Syndrome Virus (WSSV), a large dsDNA virus and the only member of the Nimaviridae family. Susceptibility to WSSV in a wide range of crustacean hosts makes it a major risk factor in the translocation of live animals and in commodity products. Currently there are no effective treatments for this disease. Understanding the molecular basis of disease processes has contributed significantly to the treatment of many human and animal pathogens, and with a similar aim considerable efforts have been directed towards understanding host-pathogen molecular interactions for WSD. Work on the molecular mechanisms of pathogenesis in aquatic crustaceans has been restricted by a lack of sequenced and annotated genomes for host species. Nevertheless, some of the key host-pathogen interactions have been established: between viral envelope proteins and host cell receptors at initiation of infection, involvement of various immune system pathways in response to WSSV, and the roles of various host and virus miRNAs in mitigation or progression of disease. Despite these advances, many fundamental knowledge gaps remain; for example, the roles of the majority of WSSV proteins are still unknown. In this review we assess current knowledge of how WSSV infects and replicates in its host, and critique strategies for WSD treatment.This work was funded by the Open Innovation Platform at the University of Exeter (Open Innovation Fund Initiative PHSW029) and by the Centre for Environment, Fisheries and Aquaculture Science (Cefas) (under seedcorn project DP318 to GDS) under the Strategic Alliance partnership between the University of Exeter and Cefas
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