Collective Coordinate Approach to the Dynamics of Various Soliton-Obstruction Systems

Various soliton-obstruction systems have been studied from analytical perspective. We have used collective coordinate to approach the dynamics of solitons as they meet a potential obstruction in a form of square barriers and holes for three models in (1+1) dimensions, namely: $\lambda\phi^{4}$ model, deformed Sine-Gordon model, and a model that give rise to Q-ball solution. We have shown that our approximated field solution is valid enough to describe the behaviour of solitons scattering off a potential obstruction.Comment: 26 pages, 18 figure

Pengaruh Pemberian Jenis Pakan Yang Berbeda Terhadap Mutu Gonad Calon Induk Ikan Ingir-ingir (Mystus Nigriceps)

The research was conducted from January to March 2016 at the Fish Hatchery and Breeding Laboratory, Faculty of Fisheries and Marine Science University of Riau Pekanbaru. The aim of this research was to evaluate suitable feed for the maturation of the gonad of bagrid catfish (Mystus nigriceps) reared with different feeding treatment (Commercial feed; cookle meat; soilworm(annelid) and chopped fresh fish. The research method used was Completely Randomized Design (CDR) with four treatments and three replications. The result showed that chopped fresh fish (Poecilia reticulata) and commercial dry food were the best food for maturating the fish gonad of bagrid catfish (Mystus nigriceps). Total fish reached matured stage IV was 16 fish (88,89%), gonad somatic index 9,06 %, relative fecundity 835 eggs/g fish, egg diameter 0,85 mm. The temperature range from 28 – 310C, pH 5 – 6, DO 5,7 – 6,8 ppm

Utilization of Leucaena Leaves Meal Gung (Leucaena Leucocephala) Fermented by Aspergillus Niger as Subtitution of Soybean Meal in the Diets on the Growth of Thai Cat Fish (Pangasius Hypophthalmus)

The research was conducted for 60 days from April to June 2017. The aim of this research was to know the utilization of fermented leucaena leaves meal as a substitution of soybean meal in the diets on the growth and feed efficiency of Thai Catfish. Completely randomized design (CRD) was used in this experiment, with one factor, five level treatment and three replications. Fish were reared in 1 m3cages with stocking density 20/cages. Feeding trial were replacing soybean meal with fermented leucaena leaves meal applied to P1 (0%), P2 (25%), P3 (50%), P4 (75%), and P5 (100%). The fish used in this research with 2,13 ± 0,39g of weight. The result of this research showed that fermented leucaena leaves meal has significant effect (P>0,05) on growth and feed efficiency of Thai Catfish. Diets which contains 75% of fermented leucaena leaves meal and 25% of soybean meal (P4) produce the highest specific growth rate (4,11%/day), feed efficiency (62,6%), feed digestibility (59,45%), and protein retention (18,85%). Based on the result of this study conclude that fermented leucaena leaves meal can be used as substitution for soybean meal in diets of Thai Catfish

The Addition of Vitamin E in Fish Diet for Gonadal Maturity of Beardless Barb (Cyclocheilicthys Apogon, Val. 1842)

The addition of vitamin E in fish diet for the gonadal maturity of beardless barb (C. apogon Val 1842) was carried out in fish Hatchery and breeding laboratory, Universitas of Riau from July to october 2015. The brooders collected from Kampar river were acclimitized for several weeks before used. The fish were reared in 12 weeks in tool recirculated water system fiber glass tanks at stocking density of 7 fish/tank. The fish were fed with dry pelled containing 35% protein at satiation. The experiment used a completely randomized design and each treatment had three replicates. The treatment were the dosage of Vitamin E i.e. P0 (0 mg/kg) as control, P1 (100 mg/kg), P2 (200 mg/kg), P3 (300 mg/kg). Result of experiment showed that the addition of 300 mg Vit. E / kg feed was better than dosage, in term of the number of fish reaching mature level (Fourth Stage) (7 fish), Gonad Somatic Index (7,93 %), Fecundity (2678 eggs) and egg diameter (0,706 mm