80 research outputs found

    21st century fisheries management: a spatio-temporally explicit tariff-based approach combining multiple drivers and incentivising responsible fishing

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    Abstract Kraak, S. B. M., Reid, D. G., Gerritsen, H. D., Kelly, C. J., Fitzpatrick, M., Codling, E. A., and Rogan, E. 2012. 21st century fisheries management: a spatio-temporally explicit tariff-based approach combining multiple drivers and incentivising responsible fishing. – ICES Journal of Marine Science, 69: 590–601. Traditionally fisheries management has focused on biomass and mortality, expressed annually and across large management units. However, because fish abundance varies at much smaller spatio-temporal scales, fishing mortality can potentially be controlled more effectively if managed at finer scale. The ecosystem approach requires more indicators at finer scales as well. Incorporating ecosystem targets would need additional management tools with potentially conflicting results. We present a simple, integrated, management approach that provides incentives for “good behaviour”. Fishers would be given a number of fishing-impact credits, called real-time incentives (RTIs), to spend according to spatio-temporally varying tariffs per fishing day. RTI quotas and tariffs could be based on commercial stocks and ecosystem targets. Fishers could choose how to spend their RTIs, e.g. by limited fishing in high-catch or sensitive areas or by fishing longer in lower-catch or less sensitive areas. The RTI system does not prescribe and forbid, but instead allows fishers to fish wherever and whenever they want; ecosystem costs are internalized and fishers have to take them into account in their business decisions. We envisage no need for traditional landings or catch quotas for the fleets while operating under the scheme. The approach could facilitate further devolution of responsibility to industry.</jats:p

    The potential role of roaming dogs in establishing a geographically novel life cycle of taeniids (Echinococcus spp. and Taenia spp.) in a non-endemic area

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    Cystic Echinococcosis (CE) is endemic in humans and livestock in many pastoral communities in Kenya. The distribution of the disease is enhanced by several factors, including livestock trade, which has allowed for the spread of CE to non-endemic areas such as western Kenya. Dogs' roaming behaviour, with consequent contamination of the environment with intestinal parasites, could then lead to parasite establishment. This study examined dogs' infection levels with taeniid eggs and their potential role in contaminating the environment with intestinal parasites. Methodology: We selected sixteen ruminant slaughterhouses in Busia and Bungoma Counties, and around each slaughterhouse we identified ten homesteads owning free-roaming dogs. We administered a questionnaire on dog management practices to the homestead owner and collected a faecal sample from the dog's rectum. In homesteads around 8 of the 16 slaughterhouses, we collared dogs with a GPS tracker to assess their movement patterns. The faecal samples were examined microscopically following zinc-chloride sieving-floatation technique for the presence of taeniid eggs and other canine intestinal parasites. Polymerase Chain Reaction – Restriction Fragment Length Polymorphism of NADH dehydrogenase subunit 1 gene and sequencing were used to confirm taeniid eggs identified during microscopy. Additionally, the Coproantigen-ELISA was used to detect the presence of taeniid antigen in a sub-set of the faecal samples. Results: Helminths detected in the 155 dogs sampled included hookworms (n = 92; 59.4%), ascarids (n = 15; 9.7%), and taeniids (n = 1; 0.6%). Through Copro-PCR, 13 eggs extracted from the sample of the only taeniid infected dog were sequenced and identified as E. canadensis (G6/7) [n = 1], Taenia multiceps [n = 1], and Taenia serialis [n = 6]; the remaining were indeterminate. Of the 77 faecal samples tested for E. granulosus sensu lato (s. l.) with the Copro-ELISA, 64 (83.1%) were negative, 12 (15.6%) were positive, while 1 (1.3%) was suspicious. The dogs travelled a median of 13.5 km daily, and 28 dogs visited the slaughterhouses during the 5-day recording period. Conclusion: The results indicate a relatively high carriage of zoonotic parasites by free-roaming domestic dogs in western Kenya, which poses a risk to human and livestock populations. We report for the first time a domestic lifecycle of Echinococcus canadensis and Taenia multiceps in western Kenya, as well as a presumptive sylvatic cycle of coenurosis by T. serialis. We recommend an extensive and ongoing Copro-antigen survey of dog faeces, broader assessment of dog parasites with zoonotic potential, adherence to slaughterhouse management practices, and dog-ownership programmes to highlight the importance of deworming and restricted dog movements

    Vegetation Cover Analysis of Hazardous Waste Sites in Utah and Arizona Using Hyperspectral Remote Sensing

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    This study investigated the usability of hyperspectral remote sensing for characterizing vegetation at hazardous waste sites. The specific objectives of this study were to: (1) estimate leaf-area-index (LAI) of the vegetation using three different methods (i.e., vegetation indices, red-edge positioning (REP), and machine learning regression trees), and (2) map the vegetation cover using machine learning decision trees based on either the scaled reflectance data or mixture tuned matched filtering (MTMF)-derived metrics and vegetation indices. HyMap airborne data (126 bands at 2.3 x 2.3 m spatial resolution), collected over the U. S. Department of Energy uranium processing sites near Monticello, Utah and Monument Valley, Arizona, were used. Grass and shrub species were mixed on an engineered disposal cell cover at the Monticello site while shrub species were dominant in the phytoremediation plantings at the Monument Valley site. Regression trees resulted in the best calibration performance of LAI estimation (R-2 > 0.80. The use of REPs failed to accurately predict LAI (R-2 < 0.2). The use of the MTMF-derived metrics (matched filter scores and infeasibility) and a range of vegetation indices in decision trees improved the vegetation mapping when compared to the decision tree classification using just the scaled reflectance. Results suggest that hyperspectral imagery are useful for characterizing biophysical characteristics (LAI) and vegetation cover on capped hazardous waste sites. However, it is believed that the vegetation mapping would benefit from the use of higher spatial resolution hyperspectral data due to the small size of many of the vegetation patches (<1 m) found on the sites.open111

    Mechanical design of the optical modules intended for IceCube-Gen2

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    IceCube-Gen2 is an expansion of the IceCube neutrino observatory at the South Pole that aims to increase the sensitivity to high-energy neutrinos by an order of magnitude. To this end, about 10,000 new optical modules will be installed, instrumenting a fiducial volume of about 8 km3. Two newly developed optical module types increase IceCube’s current sensitivity per module by a factor of three by integrating 16 and 18 newly developed four-inch PMTs in specially designed 12.5-inch diameter pressure vessels. Both designs use conical silicone gel pads to optically couple the PMTs to the pressure vessel to increase photon collection efficiency. The outside portion of gel pads are pre-cast onto each PMT prior to integration, while the interiors are filled and cast after the PMT assemblies are installed in the pressure vessel via a pushing mechanism. This paper presents both the mechanical design, as well as the performance of prototype modules at high pressure (70 MPa) and low temperature (−40∘C), characteristic of the environment inside the South Pole ice

    Simulation and sensitivities for a phased IceCube-Gen2 deployment

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    A next-generation optical sensor for IceCube-Gen2

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    The next generation neutrino telescope: IceCube-Gen2

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    The IceCube Neutrino Observatory, a cubic-kilometer-scale neutrino detector at the geographic South Pole, has reached a number of milestones in the field of neutrino astrophysics: the discovery of a high-energy astrophysical neutrino flux, the temporal and directional correlation of neutrinos with a flaring blazar, and a steady emission of neutrinos from the direction of an active galaxy of a Seyfert II type and the Milky Way. The next generation neutrino telescope, IceCube-Gen2, currently under development, will consist of three essential components: an array of about 10,000 optical sensors, embedded within approximately 8 cubic kilometers of ice, for detecting neutrinos with energies of TeV and above, with a sensitivity five times greater than that of IceCube; a surface array with scintillation panels and radio antennas targeting air showers; and buried radio antennas distributed over an area of more than 400 square kilometers to significantly enhance the sensitivity of detecting neutrino sources beyond EeV. This contribution describes the design and status of IceCube-Gen2 and discusses the expected sensitivity from the simulations of the optical, surface, and radio components
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