Study of the effect of a By-catch Reduction Panel in a twin-trawl on reducing plaice discards

Comparative fishing trials were conducted in November 2008 on the euro-cutter MFV TH-7 “Adriana Maria” on fishing grounds in the North Sea to investigate the effect of By-catch Reduction Panels inserted in a twin-trawl. In a total of 17 experimental hauls two nets were fished simultaneously, a conventional net on the starboard side and a net with a By-catch Reduction Panel inserted in the top sheet on the port side. The codend meshsize used was 80 mm. The main target species is plaice (Pleuronectes platessa L.). The By-catch Reduction Panel (BRP) tested was a square mesh panel with: 25 bars across and 22 bars deep of mesh size 150 mm, euroline™ single braid of 5 mm thickness. The panel was built in surrounding 80 mm netting and joined to 38 meshes in width and 19 meshes in depth in the port net of the twin-trawl, 12 meshes deep in front of the joining round of the codend. The panel reduced the by-catch of juvenile plaice by some 20% compared to the conventional net, but there may be a loss of marketable plaice. However, commercial losses were not confirmed by the skipper when regarding earnings over a longer period. When plaice discards are expressed as a fraction of total catch the differences were not found to be significant

Students\u27 Perspectives of NGO Service-Learning Experiences: A Case Study of Operation Smile

Past research demonstrated both strong and questionable benefits to students participating in domestic service-learning. However, we know little about high school and college students\u27 perspectives of service-learning while working with nonprofit, non-governmental (NGO) agencies that serve international populations. This qualitative, exploratory study aims to determine how students perceive their lives are impacted as a result of their service-learning experiences at Operation Smile. Data were collected from two focus groups comprised of high school and university youth. Results indicated service-learning in an international setting positively influences areas of personal growth, career choice, and future philanthropic participation. It also affects level of family, peer, and community member involvement in the NGO; and aids local target populations in developing countries. In addition to safety concerns, students mentioned difficulty in adapting after the experience as well as feelings of isolation from peers

Процес «Спілки Визволення України» та зростання селянського опору в умовах суцільної колективізації

Мета даної роботи полягає у з’ясуванні механізму використання матеріалів процесу «СВУ» на території сучасної Чернігівщини, пропагандистських цілях та реакції на нього з боку як населення, лояльного до влади, так і селян, які вперто чинили опір політиці колективізації

Ricci flows with unbounded curvature

We show that any noncompact Riemann surface admits a complete Ricci flow g(t), t\in[0,\infty), which has unbounded curvature for all t\in[0,\infty).Comment: 12 pages, 1 figure; updated reference

Catch comparison of pulse trawls vessels and a tickler chain beam trawler

Comparative fishing trials were conducted in May 2011 (week 19) on commercial beam trawlers fishing with conventional tickler chain beam trawls (on MFV GO4), pulse wings made by HFK-Engineering of Baarn, the Netherlands (MFV TX36), and pulse trawls produced by the DELMECO-Group of Goes, the Netherlands (version used on MFV TX68). The three vessels fished side-by-side as much as possible. Landings and discards of these vessels were monitored. Special emphasis was given on cod and whiting, that were dissected to study possible spinal damage. Result for TX36 and TX68 are expressed in terms of percentages of GO4. The pulse characteristics were as follows: TX36: voltage 45 V0 to peak, pulse frequency: 45 Hz, pulse duration 380 μs; electric power on single gear: 7.0 kW; TX68: voltage 50 V0 to peak, pulse frequency: 50 Hz, pulse duration 220 μs; electric power on single gear: 8.5 kW. The fuel consumption recorded over the whole week was considerably lower for the pulse trawls, i.e. on TX36 (40%) and on TX68 (54%), than for the tickler chain beam trawls used on the GO4. The net earnings (taken as gross earnings minus fuel costs) for the TX36 were almost twice as large at 186%, and for the TX68 also considerably higher at 155%. The vessels with pulse trawls caught fewer (65-69%) target species, but also less (30-50%) immature and non-target fish ('discards'), and benthic species (48-73%) than the vessel with tickler chains on these fishing grounds and in this period. The pulse gears caught fewer (19-42%) kg per hour cod than the tickler chain beam trawls, but the catches of cod on all three vessels were very small. For plaice and dab these differences were statistically proven, for brill, turbot and cod this was not the case. There was no marked difference between both pulse trawl vessels in total landings. The TX68 caught less marketable sole, but not significantly less undersized sole than the GO4. The TX36 caught less undersized sole, but here the difference in marketable fish was not significant. Catches of brill and turbot were so small that no statistically substantiated conclusion could be drawn. Only for undersized turbot the TX36 caught less. For whiting we found a demonstrable reduction in both marketable and undersized fish in both pulse fishing vessels. The TX36 caught less whiting in number per hour. The CPUEs found from the auction data and the sampled hauls correlated reasonably well for the most abundant species, such as plaice and sole. However, for less abundant species the results did not match very well, and care should be taken to increase the sampling rate in future comparative fishing studies. Spinal fracture in cod occurred under pulse stimulation but to a limited extent in both marketable and undersized fish. There is an indication that this happens slightly more on TX68 (11%) than on TX36 (7%). Whiting hardly seems to suffer any damage

On Rank Problems for Planar Webs and Projective Structures

We present old and recent results on rank problems and linearizability of geodesic planar webs.Comment: 31 pages; LaTeX; corrected the abstract and Introduction; added reference

Medium Energy Ion Scattering of Gr on SiC(0001) and Si(100)

Depth profiling of graphene with high-resolution ion beam analysis is a practical method for analysis of monolayer thicknesses of graphene. Not only is the energy resolution sufficient to resolve graphene from underlying SiC, but by use of isotope labeling it is possible to tag graphene generated from reacted ethylene. Furthermore, we are able to analyze graphene supported by oxidized Si(100) substrates, allowing the study of graphene films grown by chemical vapor deposition on metal and transfered to silicon. This introduces a powerful method to explore the fundamentals of graphene formation