Angular dependence of domain wall resistivity in artificial magnetic domain structures.

We exploit the ability to precisely control the magnetic domain structure of perpendicularly magnetized Pt/Co/Pt trilayers to fabricate artificial domain wall arrays and study their transport properties. The scaling behavior of this model system confirms the intrinsic domain wall origin of the magnetoresistance, and systematic studies using domains patterned at various angles to the current flow are excellently described by an angular-dependent resistivity tensor containing perpendicular and parallel domain wall resistivities. We find that the latter are fully consistent with Levy-Zhang theory, which allows us to estimate the ratio of minority to majority spin carrier resistivities, rho downward arrow/rho upward arrow approximately 5.5, in good agreement with thin film band structure calculations.

Impact of species composition and artificial feed on the growth of carps

Two trials conducted to demonstrate the suitability of composite carp culture in a small, seasonal, shallow village pond with varied species composition and stocking density indicated the possibility of obtaining higher production with reduced number of species. During the first trial, the Indian major carps, silver carp, common carp and fringe lipped carp were stocked at a density of 5625 fingerlings/ha in the pond in which the maximum water spread area was 1600m². The fish grown over a period of seven months yielded a production of only 242 kg. However, during the second trial, an increase in production by 60.33% was achieved over the same period in the same pond by stocking only the Indian major carps and common carp at a density of 4687.5 fingerlings/ha and feeding them daily with silkworm faecal matter based artificial feed at about 5% of their body weight. The results indicated that for seasonal, shallow ponds stocking of only three species of carps, namely, catla, rohu and common carp would suffice to get optimum yield.

Isolation and culture in artificial media of Lagenidium from Penaeus monodon larvae

Fungal infection of P. monodon larvae is a problem in hatchery operations. The fungus, which attacks the nauplius to postlarval stages and causes up to 100% mortality, has been tentatively identified as belonging to the genus Lagenidium . This pathogenic organism has recently been isolated and cultured. A description is given of the fungus, and features of its biology and pathology are discussed.

A preliminary study on the evaluation of casein, shrimp meal, squid meal and spirulina as protein sources of Penaeus monodon (Fabricius) postlarvae

P. monodon postlarvae were fed with fresh brown mussel (Modiolus metcalfei ) meat, and artificial diets containing casein, shrimp (Metapenaeus ensis ) meal, squid (Loligo ) meal, and Spirulina as protein sources at a rate of 20% of their biomass per day for a period of 10 days. No statistical difference was found among the weight gains of shrimp fed on various experimental diets. However, shrimp fed squid meal diet had highest weight gain followed by shrimp meal, fresh brown mussel meat, casein and Spirulina . Shrimp fed squid meal diet had a significantly better feed conversion and those receiving other experimental diets. Poorest fed conversion was observed in shrimp fed Spirulina . The protein efficiency ratio was statistically highest for the squid meal diet, with the lowest value again for Spirulina diets. Survival rate was significantly highest for shrimp fed the shrimp meal diet. No statistical differences were found among shrimp fed other experimental diets. Appropriate data are tabulated.

Observations on the artificial fertilization of eggs and larval rearing of the grey mullet, Mugil cephalus L.

The results are presented of attempts to artificially fertilize Mugil cephalus eggs in the Philippines. Embryonic development is outlined and rearing of the larvae described. Mass mortality occurred during week 3 of rearing.

Fishwater and agar as binders in a prawn diet

The objectives of the study were to find out the proportion of water to fish fins, skin and bones that would give a good gel and to determine the effect of a combination of fish water and commercial crude agar on the water stability of the prawn diet. Under the conditions of the experiments it was concluded: (1) Fish water and commercial agar or agar bar gave the most stable pellet, 65% water stability; (2) a strong gel is obtained when one part shark fin is boiled in 1.5 parts water; (3) more fish water can be obtained from guitar fish than from shark fish.

Improvement of diet attractability for Penaeus monodon by supplementing various attractants

An experiment was undertaken to test the effect of supplemental krill meal, earthworm meal, glycine, sucrose or mussel water on diet attractibility of Penaeus monodon. Only glycine or mussel water significantly improved diet attractibility

Study of effect Rosmarinus officinalis oil and nisin on the growth of Streptococcus iniae in lab conditions and fillets of rainbow trout (Oncorhynchus mykiss)

Fish are an important part of a healthy diet since they contain high quality protein, but typically present a low fat percent when compared to other meats. Fish is an extremely perishable food commodity. On the other hand, food borne diseases are still a major problem in the world, even in well-developed countries. The increasing incidence of food borne diseases coupled with the resultant social and economic implications means there is a constant striving to produce safer food and to develop new antimicrobial agents concerns over the safety of some chemical preservatives and negative consumer reactions to preservatives they perceive as chemical and artificial, have prompted on increased interest in more ‘‘naturalgreen’’ alternatives for the maintenance or extension of product shelf-life. Particular interest has focused on the potential applications of plant essential oils. However, to establish the usefulness of natural antimicrobial preservatives, they must be evaluated alone and in combination with other preservation factors to determine whether there are synergistic effects and multiple hurdles can be devised. In this study, were evaluated the effects of different concentrations of Rosmarinus officinalis and nisin and storage time (15 days) on growth of Streptococcus iniae GQ850377 in a lab conditions and a food model system (fillets of rainbow trout) in 4 and 8 °C. In addition, we also studied multi factorial effects of four different concentration of rosemary, three different concentrations of nisin, two different levels of pH in 3 temperature 4,15 and 37 °C on log% of S.iniae during 43 days in BHI broth. The results on growth of S. iniae were evaluated using SPSS 20.0 statistical software and analyzed the logarithm of total count of the bacterial by Tukey Test. Results were considered statistically significant when P<0.05. MIC and MBC values of rosemary and nisin were 0.03, 0.075 % and 5, 40 μg/mL, respectively. The growth of S. iniae was effected significantly (P<0.05) by rosemary and nisin and also combination of rosemary and nisin in 4 and 8 °C. Samples treated with 0.135 and 0.405 % of rosemary showed a significant decrease on the growth of the bacteria compared with control sample(P<0.05). The most ١٤٦ inhibitory effects were seen in samples treated with 0.135 and 0.405% of rosemary until 9 days after storage. Also, the synergism effects of rosemary and nisin on the growth rate of bacteria was significant (P<0.05) compared with untreated samples and samples treated with the rosemary or nisin, only. Synergistic effects was observed at concentration of 0.405% rosemary and 0.75 μg/mL nisin in both temprature. Results of this study showed that different concentration of rosemary a significant inhibitory effect (P<0.05) on log% of S. iniae, in BHI broth in pH 5.5 and 7 in 4,15 and 37 °C during 43 days. In concentration of 0% rosemary (control) in pH 5.5 and 7 and 37°C, log% were 1.099 and 3.15, whereas in concentration of 0.015% rosemary were -4/241 and 1.454, respectively. The use of essential oils may improve food safety and overall microbial quality. If essential oils were to be more widely applied as antibacterials in foods, the organoleptic impact would be important. In addition, it is recommended to apply essential oils or their compounds as part of a hurdle system and to use it as an antimicrobial component along with other preservation techniques. Thus essential of R. officinalis with high antibacterial activity selected in this study could be a potential source for inhibitory substances against some food-borne pathogens and they may be candidates for using in foods or food-processing systems.

The study of artificial propagation efficiency and fingerlings production of Coregonus lavaretus

In order to study of the artificial propagation efficiency in white fish (Coregonus lavaretus) and its fingerlings producing in IRAN, a 9 mounts study project was been done which during it, the characteristics of the matures and brood stocks fishes, the condition of their natural and artificial propagation, and the characteristics of produced frys, were been studied. Throughout the total 82 pieces caught fishes during September til February 2003, 10 pieces of them were the female brood stocks which during the catch time did not have spouse. The study of these fishes showed that there was no significant correlation between their weight and their length. The most and the least absolute fecundity of these brood stocks were 19120 and 11496 respectively. The artificial propagation was been done by 5 males and 4 females broods took which 57602 ova, with 89/2% fertilization rate, earned from them. The incubation period prolonged 55 days in 8°c. At the end of the incubation, 23913 larvae released. So the artificial propagation efficiency was calculated 41/51% in this study. Yolk sack absorption prolonged 4 days. 3 different food treatment were considered for fry breeding which contain of Brachiouns plicatilis as live food, salmon starter food as commercial food, and the mixed of equal amounts of live and commercial foods as third treatment. For each treatment, 3 repeat has been considered. Breeding duration prolonged 13 weeks throughout this period, different characteristics of fry were been studied weekly. The breeding results showed that there was very significant correlation between the weight and the length of frys. However the live food provided better results in growth and survival rate of frys during breeding initial 6 weeks. More ever, commercial food, in some characteristics, provided more acceptable results in comparing the live food after sixth week. The results of this study project showed that the artificial propagation in whitefish is possible in IRAN and the producing of its frys in order to restocking or introducing this species to the other Iranian suitable water resources is executable. Based on the earned information from this study, the suitable time for natural spawning of whitefish in IRAN (Amirkabir dam lake) determined between 10th January til 20th February.

The study of different protein in diet and water salinity on growth and survival rate in Pacific white shrimp (Litopenaeus vannamei)

In this research reared white western shrimp (Litopenaeus vannamei ,Boone, 1931) with five diet with five different protein level contain 20%, 25%, 30%, 35% and 40% and three salinity level contain 15-17 ppt, 27-30 ppt,and 40-45 ppt researched protein percent effect and water salinity on growth, survival, feed conversion ratio, hemolymph osmolatity, hemolymph protein and corpse protein contain. In this research was 15 sorrow with 3 repeat and used from 45 tanks with 300 liters capacity. Shrimps first weight average was about 2 grams and after 60 days culture cropped down results: Shrimps biomass growth in 15-17 ppt salinity was higher than anther salinities who had meaning different with growth in 40-45 ppt salinity ( p< 0.05). But hadn’t meaning different with growth 27-30 ppt salinity. survival rate in 15-17 ppt salinity was 97.03 who was lower than another salinities. survival percent in 24-30 ppt salinity and 40-45 ppt salinity was 99.33% Highest biomass growth in different diets was in diet number 5 with 40 percent protein that it had meaning different with another diets (p<0.05) . although with informed to product expense in different diets. One kilogram shrimp product expense in different diets hadn’t meaning different (P<0.05) Survival rate in different diets hadn’t meaning different lowest feed conversion ratio was 1.67 in 15-14 salinity that hadn’t meaning different with another salinities also corpse protein quantity in different salinities and different diets hadn’t meaning different. Hemolymph Osmolality in 15-17 ppt salinity was 573.88 mOsm/kg had meaning different with hemolymph osmolality in 27-30 ppt salinity that was 650. 380 mOsm/kg and in 40-45 ppt salinity was 630.38 mOsm/kg. Hemolymph protein in 15-17 ppt salinity was 124.72 mg/ml had meaning different with hemlymph protein in 27-30 ppt salinity that was 136.52 mg/ml but hadn’t meaning different with hemolymph protein in 40-45 ppt salinity that was 128.84 mg/ml. Hemolymph protein in different diets hadn’t meaning different (p<0.05). Keywords: shrimp, Litopenaeus vannamei, protein , salinity, growth, survival rate, FCR, hemolymph osmolality, hemolymph protein.

Seasonal variations in the activity budget of Nomascus concolor jingdongensis at Mt. Wuliang, Central Yunnan, China: Effects of diet and temperature

We studied seasonal variation in the activity budget of a habituated group of Nomascus concolor jingdongensis at Mt. Wuliang, Central Yunnan, China from March 2005 to April 2006 via scan sampling at 5-min intervals. The study site is near the northern extreme of the distribution of hylobatids, at high altitude with extreme seasonality of temperature and rainfall. During the day, feeding manifested a bimodal pattern of high activity levels in mid-morning and mid-afternoon, whereas resting reached a peak at midday, with proportionally less time used for traveling. Annually, the group spent an average of 40.0% of the time resting, 35.1% feeding, 19.9% traveling, 2.6% singing, 1.2% playing, and 1.3% in other activities. The proportion of time allocated to activities showed significant monthly variations and was influenced by the diet and temperature. Gibbons increased traveling and playing time and decreased feeding time when they ate more fruit, and they decreased traveling, singing, and playing time and increased feeding time when they ate more leaves. Moreover, when the temperature was low, the gibbons decreased time traveling and increased time resting. In summary, black-crested gibbons employed high-effort activities when they ate more fruit and energy-conservation patterns when they ate more leaves and in low temperature. Behavioral data from the site are particularly useful in understanding gibbon behavioral adaptations to different sets of ecological conditions.

Gibbons under seasonal stress: the diet of the black crested gibbon (Nomascus concolor) on Mt. Wuliang, Central Yunnan, China

The diet of a habituated group of black crested gibbon (Nomascus concolor jingdongensis) was studied from March 2005 to April 2006 in the Wuliang Mountains, central Yunnan, China. Gibbons consumed 77 different plant species, one mammal-, two bird-, one li