DIFFERENTIAL GEOMETRICAL METHODS IN THE STUDY OF OPTICAL-TRANSMISSION (SCALAR THEORY) .2. TIME-DEPENDENT TRANSMISSION THEORY

By generalization of the methods presented in Part I of the study [J. Opt. Soc. Am. A 12, 600 (1994)] to the four-dimensional (4D) Riemannian manifold case, the time-dependent behavior of light transmitting in a medium is investigated theoretically by the geodesic equation and curvature in a 4D manifold. In addition, the field equation is restudied, and the 4D conserved current of the optical fluid and its conservation equation are derived and applied to deduce the time-dependent general refractive index. On this basis the forces acting on the fluid are dynamically analyzed and the self-consistency analysis is given.

Salmon stocking by the Lancashire River Authority: investigations into the requirements and methods best suited to the area

All species of fish are able to propagate and maintain their numbers provided that no adverse influence occurs to change the compatible environment, the salmon is no exception. Propagation of fish by artificial means has long been a subject of discussion amongst fishery workers and views have been expressed (both favourable and unfavourable) on the merits of the various methods employed. In an attempt to discover whether artificial propagation was necessary and also to find the best methods of propagation to adopt in the various rivers, a phased programme of investigation into natural spawning efficiency and the results obtained by various methods of artificial propagation was started in the Lancashire River Board area during 1957. The object being to seek information on: (1) The survival of ova from natural spawnings to the eyed and alevin stages. (2) The population density of feeding fry (from natural spawnings) at various intervals of development. (3) The viability of green ova and eyed ova- when planted artificially. (4a) The survival to 0+ parr from implants of eyed ova unfed fry and fed fry. (4b) Populations per unit area of 0+ parr from various planting densities of eyed ova, unfed fry and fed fry. Sampling stations were selected on the Rivers Ribble, Lune and Wyre watersheds for the purpose of marking and examination of natural salmon redds.

Evaluating methods for estimating rare events with zero-heavy data: a simulation model estimating sea turtle bycatch in the pelagic longline fishery

Estimating rare events from zero-heavy data (data with many zero values) is a common challenge in fisheries science and ecology. For example, loggerhead sea turtles (Caretta caretta) and leatherback sea turtles (Dermochelys coriacea) account for less than 1% of total catch in the U.S. Atlantic pelagic longline fishery. Nevertheless, the Southeast Fisheries Science Center (SEFSC) of the National Marine Fisheries Service (NMFS) is charged with assessing the effect of this fishery on these federally protected species. Annual estimates of loggerhead and leatherback bycatch in a fishery can affect fishery management and species conservation decisions. However, current estimates have wide confidence intervals, and their accuracy is unknown. We evaluate 3 estimation methods, each at 2 spatiotemporal scales, in simulations of 5 spatial scenarios representing incidental capture of sea turtles by the U.S. Atlantic pelagic longline fishery. The delta-log normal method of estimating bycatch for calendar quarter and fishing area strata was the least biased estimation method in the spatial scenarios believed to be most realistic. This result supports the current estimation procedure used by the SEFSC.

Recent advances in our knowledge of the biology and conservation of mahseers

Mahseers (Tor khudree), at one time considered to be of single species, are now represented by 6 valid species distributed all over India. Studies on their food habits, ecology of spawning grounds, eggs, larval development and especially methods of artificial propagation have advanced in recent years. Transport of eggs of Tor khudree by air in moist cotton has been possible for easy distribution. Breeding of T. khudree not only by hypophysation, but even without it in small ponds by manipulation of flow of water, exercise and feed has also been possible. Fry and fingerlings of T. khudree are being distributed to many of the states in the country to help conserve the species.

Contrasting high-resolution characteristic shock-capturing methods in aeroacoustic test problems

Two shock-capturing methods are considered. One is based on a standard conservative Roe scheme with van Leer's MUSCL variable extrapolation method applied to characteristic variables and a Runge-Kutta time stepping scheme. The other is based on the novel CABARET space-time scheme, which uses two sets of staggered variables, one for the conservation step and the other for characteristic splitting into local Riemann invariants. The methods are compared in a range of 2-D inviscid compressible flow test cases. Copyright © 2008 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Species identification and authentication of some of the most important seafood products in Iranian markets using biotechnological methods based on DNA

This study describes the molecular identification of sixteen fish species present in processed products imported into Iran for human consumption. DNA barcoding using direct sequencing of about 650 bp of the mitochondrial Cytochrome Oxidase subunit I gene revealed incorrect labeling (31.25%). Substitution of fish species constitutes serious economic fraud, and our results increase concern regarding the trading of processed fish products in Iran from both health and conservation points of view.

Report of the training on seagrass conservation and monitoring, Myanmar, 26 April -3 May, 2015

Trainers from the region contributed theory and practical training to trainees from government departments, universities and NGOs relevant to conservation of seagrasses and monitoring methods.

The impact of fishing gears and methods: with recommendations for management of the fisheries of Lakes Victoria, Kyoga and Nabugabo

Historical analysis has shown that use of destructive fishing gears and methods contributed much to the initial depletion of fish stocks from Lakes Victoria and Kyoga. From about 1930 to 1960, the fisheries of Lake Victoria were managed by controlling the mesh size of gill nets. Gill net s of less than 127 mm (5) stretched mesh had been prohibited on Lake Victoria because they cropped immature Oreochromis esculentus (Ngege) which were at that time the most important commercial species. When the mesh size restriction was repealed in the Ugandan, Tanzanian and Kenya, there was a shift to smaller meshes which cropped immature tilapia and other large species and led to a collapse in the fishery.

The role of satellite lakes in conservation of fish species diversity in the Lake Kyoga basin

Lakes Victoria and Kyoga had, a diverse fish fauna, which was important as food for local population and valuable in scientific studies. Over the past twenty years, the diversity of fish in these lakes had declined due to over-exploitation, introduction of new fish species including the piscivorous Nile perch and degradation of fish habitat. Studies of satellite lakes in the Victoria and Kyoga lake basins suggested that some of these lakes harboured species which had been lost from the main lakes. In order to better understand the extent, to which these satellite lakes may serve as refugia, a faunal survey was undertaken to determine the distribution and nature of the taxa found. Seven satellite lakes and the eastern end of the main Lake Kyoga adjacent to these minor lakes were surveyed over a two-year period for fish species diversity. A total of 68 fish species were recorded of which 41 were haplochromines. Almost all the native non cichlids which occurred in the main lakes (Victoria and Kyoga) before the Nile perch upsurge recorded. Lakes Nawampasa, Gigati, Kawi, Agu and Nyaguo had the highest fish species and trophic diversity. The trophic diversity of haplochromines (based on Shannon Weaver Index) was highest in Lake Nawampasa (1.28), followed by Gigati (1.25), Kawi (1.18), Agu (0.8), Lemwa (0.81), Nyaguo (0.35) and was lowest in the main Lake Kyoga. Potential threats to these lakes were from collectors of ornamental fish species, especially the haplochromines, the spread of the predatory Nile perch and the water hyacinth, which are already in Lake Kyoga, and the destruction of macrophytes through harvesting of papyrus and reclamation for agriculture. The human population around these lakes harvested the fishes for food but the levels of exploitation were still low because the lakes were adjacent to main Lake Kyoga, the major supply of fish. Ornamental fish dealers were encouraged to start captive breeding of the fish for export to reduce pressure on the lakes and demonstrations for breeding were set up at FIRI in Jinja. Meetings and seminars were held with some of the communities living around the lakes sampled and the importance of fish species found in these lakes and the dangers of destructive practices discussed. Representatives of all taxa of fish caught from the lakes were preserved, catalogued and stored in the FIRI Museum. Results from this survey support the motion that these satellite lakes are important refugia for endemic diversity. Based on survey, we recommend that SaIne of these lakes like Nawampasa, Gigati, Kawi, Agu and Nyaguo could be designated as conservation areas of species threatened in the main lakes. One of the factors that seem to have prevented the spread of Nile perch into Kyoga Minor lakes seems to have been the presence of extensive swamps around these lakes and the low oxygen levels that exist in these habitats. Clearing of swamps and vegetation that separate Kyoga minor lakes from the main lake should be avoided to prevent Nile perch from spreading into these lakes.

Abundance and conservation status of the Yangtze finless porpoise in the Yangtze River, China

middle and lower reaches of the Yangtze River, China. It is the only freshwater population of porpoises in the world and is currently listed as Endangered by IUCN. In November and December 2006 we used two boats and line transect methods to survey the entire current range of the population, except for two lakes (Poyang and Dongting). Sighting results were similar for both boats, so we pooled all data and analyzed them using two line transect models and a strip transect model. All models produced similar estimates of abundance (1111, 1225 and 1000). We then added independent estimates of the number of porpoises from the two lakes for a total estimate of approximately 1800 porpoises. Our findings indicate that the population continues to decline and that its distribution is becoming more fragmented. Our current estimate in the main river is slightly less than half the estimate from surveys between 1984 and 1991 (which was probably an underestimate). We also found an apparent gap in the distribution of porpoises between Yueyang and Shishou (similar to 150 km), where sightings had previously been common. Continued threats to Yangtze finless porpoises include bycatch in unregulated and unselective fishing, habitat degradation through dredging, pollution and noise, vessel strikes and water development. Immediate protective measures are urgently needed to ensure the persistence of finless porpoises in the Yangtze River. The survey design and analytical methods developed in this study might be appropriate for surveys of cetaceans in other river systems. (c) 2008 Elsevier Ltd. All rights reserved.

A theoretical framework of tracer methods for marine sediment dynamics

A new theoretical framework of tracer methods is proposed in the present contribution, on the basis of mass conservation. This model is applicable for both artificial and natural tracers. It can be used to calculate the spatial distribution patterns of sediment transport rate, thus providing independent information and verification for the results derived from empirical formulae. For the procedures of the calculation, first, the tracer concentration and topographic maps of two times are obtained. Then, the spatial and temporal changes in the concentration and seabed elevation are calculated, and the boundary conditions required are determined by field observations (such as flow and bedform migration measurements). Finally, based upon eqs. (1) and (13), the transport rate is calculated and expressed as a function of the position over the study area. Further, appropriate modifications to the model may allow the tracer to have different densities and grain size distributions from the bulk sediment.

Shifting ranges and conservation challenges for lemurs in the face of climate change.

Geospatial modeling is one of the most powerful tools available to conservation biologists for estimating current species ranges of Earth's biodiversity. Now, with the advantage of predictive climate models, these methods can be deployed for understanding future impacts on threatened biota. Here, we employ predictive modeling under a conservative estimate of future climate change to examine impacts on the future abundance and geographic distributions of Malagasy lemurs. Using distribution data from the primary literature, we employed ensemble species distribution models and geospatial analyses to predict future changes in species distributions. Current species distribution models (SDMs) were created within the BIOMOD2 framework that capitalizes on ten widely used modeling techniques. Future and current SDMs were then subtracted from each other, and areas of contraction, expansion, and stability were calculated. Model overprediction is a common issue associated Malagasy taxa. Accordingly, we introduce novel methods for incorporating biological data on dispersal potential to better inform the selection of pseudo-absence points. This study predicts that 60% of the 57 species examined will experience a considerable range of reductions in the next seventy years entirely due to future climate change. Of these species, range sizes are predicted to decrease by an average of 59.6%. Nine lemur species (16%) are predicted to expand their ranges, and 13 species (22.8%) distribution sizes were predicted to be stable through time. Species ranges will experience severe shifts, typically contractions, and for the majority of lemur species, geographic distributions will be considerably altered. We identify three areas in dire need of protection, concluding that strategically managed forest corridors must be a key component of lemur and other biodiversity conservation strategies. This recommendation is all the more urgent given that the results presented here do not take into account patterns of ongoing habitat destruction relating to human activities.

Integrating methods for ecosystem service assessment and valuation: Mixed methods or mixed messages?

A mixed-method approach was used to assess and value the ecosystem services derived from the Dogger Bank, an extensive shallow sandbank in the southern North Sea. Three parallel studies were undertaken that 1) identified and quantified, where possible, how indicators for ecosystem service provision may change according to two future scenarios, 2) assessed members of the public's willingness-to-pay for improvements to a small number of ecosystem services as a consequence of a hypothetical management plan, and 3) facilitated a process of deliberation that allowed members of the public to explore the uses of the Dogger Bank and the conflicts and dilemmas involved in its management. Each of these studies was designed to answer different and specific research questions and therefore contributes different insights about the ecosystem services delivered by the Dogger Bank. This paper explores what can be gained by bringing these findings together post hoc and the extent to which the different methods are complementary. Findings suggest that mixed-method research brings more understanding than can be gained from the individual approaches alone. Nevertheless, the choice of methods used and how these methods are implemented strongly affects the results obtained.