Large single grain (RE)-Ba-Cu-O superconductors with nano-phase inclusions

Nano-phase (5-20 nm) particles of YBa2(Cu0.5M 0.6)O6 [where M = Nb, Ta, Mo, W, Zr and Hf] have been introduced successfully into RE-Ba-Cu-O single grain superconductors. A study to enlarge the size of a single grain containing these particles has been carried out involving measurement of the growth rate as a function of YBa 2(Cu0.5M0.6)O6 phase concentration and degree of un-dercooling. The influence of the change in YBa2 (Cu0.8M0.5)O6 concentration on microstructural features is also investigated and the superconducting properties of these large grain superconductors are presented. © 2005 IEEE.

The fisheries resources of Lake Nakivali

Lake Nakivali is one of the four small lakes that form what is known as the koki lake sysyem. It is 14km long,6km wide.26km sqaured in area and has maximum depth of 3.5m at high water level. The lake is located in lake-swamp complex with river Rwizi as the principle inflow, and a number of peripheral lakes among which are four major ones,i.e Lake Nakivali, Mburo, Kachira and Kijanebalola. Lake Nakivali is a controlled lake with four official landing sites, namely: Kikusi, Kahirimbi, Kashojwa and Rukinga. The latter three are located within a Refugee settlement whereas Kikusi is outside. The Nakivali Refugee settlement initially established for Rwandese of Tutsi origin in 1963, now has at least seven nationalities which include people from Rwanda, Democratic Republic of Congo, Somalia, Sudan, Ethiopia, Kenya and Eritrea. By the end of 2006, the lake’s hinterland of about 378 km squared contained 43,448 people of whom 22,448 were refugees. This large population has had stressful impacts on both land and lake resources to the extent that now there is an apparent overfishing on the lake.

A new one-boat mid-water trawl for Indian waters

Even though the rich and variegated pelagic fishery resources of our west coast are well known much has to be done for a judicial and systematic exploitation on a commercial scale. To fill up this lacuna the present paper describes in detail a new design of 10.5 m four-equal panel mid-water trawl, its rigging and operation from a medium size vessel. Comprehensive comparative efficiency studies of this gear with a 10.5m unequal panel mid-water trawl established the superiority of the new gear. From the results based on the mouth opening, resistance and the catch it is opined that this new gear can not only be used on a commercial scale in harvesting the seasonal pelagic fishery, but also as a secondary supporting gear in shrimp fishery in places like Veraval, where there is a commercially exploitable yield of quality fishes like hilsa, pomfret, seer etc., without much modification from conventional stern trawlers.

大额牛精液低温冷冻保存方法

本发明涉及一种大额牛精液低温冷冻保存方法，属生物技术领域。本发明利用滴冻法对大额牛精液进行冷冻保存。冷冻液的配方为卵黄15％-20％v/v、甘油3％-6％v/v、乳糖1.0M-1.5M和蔗糖1.0M-1.5M；防冻液与精液稀释比例为1∶10、稀释后的精液放置在室温下平衡1小时，再转移到4℃冰箱中平衡3小时；冷冻精液的品质判定指标为：解冻复速率不低于70％；精子体外存活时间在解冻后放入37℃、5％CO2培养箱中进行培养1小时后，运动度不小于30％；金黄地鼠裸卵穿透率不低于38％；精液在50mOsm/kg的低渗溶液中，38℃的5％CO2培养相中培养1小时，精子肿胀率不低于39％。本发明具有实用且效果可靠，提供的大额牛冷冻精液品质的评定方法和判定指标科学、规范等优点。

Survey of biosystematic and sexual reproductive physiology in Holothuroidea on Hormozgan Province

Sea cucumbers belong to phylum Echinodermata, order Holothuroidea are an abundant and diverse group of Invertebrates, with over 1400 species occuring from the intertidal to the deepest oceanic trenches. Sea cucumbers are important components of the food chain in temperate and coral reef ecosystems and they play an important role as deposite feeders and suspension feeders. Rapid decline in populations may have serious consequences for the survival of other species that are part of the same complex food web,as the eggs, larve and juveniles constitute an important food source for the other marine species including crustaceans, fish and mollusks. In addition sea cucumbers are often called the earthworms of the sea, because they are responsible for the extensive shifting and mixing of the substrate, and recycling of detrital matter. Sea cucumbers consume and grind sediment and organic material into finer particles , turning over the top layers of sediment in lagoons , reefs and other habitats and allowing the penetration of oxygen. While the taxonomy of the holothurian families is generally well known , the distinction of similar species is difficult. There are relatively few holothurian taxonomist.Most sea cucumber species can be identified by Holothurin taxonomists by using the calcareous skeletal ossicles found in the body wall. In this study , at first a sea cucumber from Kish island in Persian gulf has recognized. Individuals collected from west and east extend far away into north and south of coral reefs by diving. I have checked them morphologically and anatomically.Then with key to the orders of the Holothuroidea, They belong to the Aspidochirotida with key to the families of Aspidochirotida, they were in Stichopodidae families and with key to the genus of Stchopodidae, they were Stichopus. Then ossicles were extracted at National Museum of Natural History, by Dr David Pawson. The ossicles were measured on a transect across a slide prepared from the mid-dorsal region of each specimen.The one we have in the shallow waters of Kish island, is Stichopus hermanni, a massive holothurian, body broad, considerably flattened ventraly ,the dorsal side slightly arched and the lateral sides almost vertical; body wall fairy thick and soft ; mouth subterminal; anus central; tentacles usually 20 in number of length and leaf shaped. Numerous ossicles consisting of table with large discs having usually 7 to 15 peripheral holes, but often irregular or incomplete and spire of moderate height ending in a group of spinelets, rosettes of variable development, and c-shaped rods. Color (exept papillae)partly remained after preservation in alcohol which is found at the depth of 4 to 8 meters, on coral reef. Furthermore, the sexual reproductive cycle was described using standard methods. Gonads were removed and transferred to Bouin's fixative for four weeks and then processed according to standard embedding technique. To prevent the loss of tubule contents during embedding, the tubule sections, were cut well beyond the segment selected for sectioning. For each individual, six sections, each section with 5µm diameter by microtome were cut from tubules. These sections were first placed on gelatin coated slides (the gelatin was heated to 42°c) and then transferred to the oven at 37°c for one hour. This technique usually prevents the fragil tubules from breaking and the loss of gametes. The slides were stained with Eosin and Hematoxylin, and good resolution of the various cell types achieved.A second series of slides was stained with the Periodic Acid Schiff(PAS) to identify polysaccharides(glycogen). Monthly sampling was occurred.The sexual reproductive cycle was defined through the combined use of these criteria: Monthly percentages of the gonad stages for each sex, the monthly gonad index (GI) , given as the ratio of the wet gonad weight (G) to the dray weight (DW)and the monthly percentage of individuals that undetermined sex. The gonad consists of two tufts of tubules on which saccules develop. Gonadal development was classified into five stages: post spawning, recovery, growth, advanced growth, and mature stage that were adapted from the earlier studies of holothurians. Histological preparations showed that the sex of larger individuals could be identified by the presence of oogonia and young oocytes in females, and spermatogonic stages in males.The mean diameter of the tubules and gonadal mass follow annual cycles, increasing from late winter through spring, and dropping abruptly after spawning in the summer. Gametogenesis is generally a prolongate process and begins in March. By summer the ovarian tubules contain oocytes with diameter of 120-240 pm and the testicular tubules contain an abundance of spermatozoa (diameter 5-6 gm ).Following spawning the predominant activity within the spent tubules is phagocytosis of the residual gamets.The active phase of gametogenesis (March to July), coincides with an increasing photoperiod regim, and an accelerated gametogenesis occurs in July when temperature is high. Throughout the year, the gonad of Stichopus hermanni is larger in males than in females, and this is due to the number of tubules in the testis rather than to tubules length or diameter.

The water hyacinth problem and the biological control option in the highland lake region of the upper Nile basin: Uganda's experience

The rapid proliferation and extensive spread of water hyacinth Eichhornia crassipes (Mart) Solms in the highland lakes of the Nile Basin within less than 15 years of introduction into the basin in the 1980s pauses potential environmental and social economic menace if the noxious weed is not controlled soon. The water weed has spread all round Lake Victoria and, in Uganda where infes tation is mos t severe, water hyacinth estimated at 1,330,000 ton smothers over 2,000 ha of the lakeshore (August,1994). Lake Kyoga which already constantly supplies River Nile with the weed is infested with over 570 ha, while over 80% of the river course in Uganda is fringed on either side with an average width of about 5m of water hyacinth. As the impact of infestation with water hyacinth on water quality and availability, transportation by water, fishing activities, fisheries ecology, hydro-power generation etc becomes clear in Uganda, serious discussion is under way on how to control and manage the noxious weed. This paper pauses some of the questions being asked regarding the possible application of mechanical and chemical means to control the water weed.Uganda has already initiated the use of biological control of water hyacinth on Lake Kyoga with a strategy to use two weevils namely Neochetinabruchi and Neochetina eichhorniae. The strategy to build capacity and infrastructure for mass multiplication and deployment of biological control of the weevils in the field developed in Uganda by the Fisheries Research Insti tu te (FIRI) and the Namulonge Agricultural and Animal production Research Insti tute (NAARI) is proposed in outline for evaluation. Plans to deploy this strategy on lake Kyoga are under way

Experimental study of homogenisation in grid turbulence

Turbulence statistics have been measured immediately downstream of a regular grid made of round rods with rod spacing M. 2D-2C PIV was used to analyse a measurement area of 14M x 4M in the down and cross-stream directions respectively. The relevant Reynolds number span the range Re M = U ∞M/ν = 5 500 - 16 500. The Reynolds shear stresses recorded on two parallel measurement planes differently located relative to the grid exhibit significant discrepancies over the first 5M, but have completely homogenised in the cross-stream direction by x/M = 7. The downstream evolution of the two-point velocity correlation functions shows a progressive loss of coherence and a clear trend towards the expected isotropic behavior. The same conclusions apply to measurements taken in the wake of another regular grid made of square rods. Changes in the vortex shedding pattern from the grid were observed at the lowest Reynolds number, with two of the four rod wakes captured shedding in phase with each other but in anti-phase with a third one. The impact of this early flow coherence on the turbulence statistics did not persist due to the homogenisation process.

Modelling effects of axial load on behaviour of pile groups in laterally-spreading soil

Previous research into the behaviour of piled foundations in laterally-spreading soil deposits has concentrated on pile groups that carry small or negligible axial loads. This paper presents dynamic centrifuge test results for 2×2 pile groups with bending and geometric properties similar to real 0.5m diameter tubular steel and solid circular reinforced-concrete field piles. Axial loads applied represented upper-bounds on typical working loads. The simultaneous scaling of the relevant properties controlling both lateral and axial behaviour allows comparisons to be drawn regarding the particular mechanisms of failure that would dominate for each type of pile. Flexible reinforced-concrete piles which tend to carry lower loads were found to be dominated by lateral effects, while steel piles, which are much stiffer and usually carry greater loads are dominated by settlement considerations. © 2006 Taylor & Francis Group, London.

New evidence for the origin and behaviour of deep ocean 'crusts'

In situ tests in deep waterWest African clays show crust-like shear strengths within the top few metres of sediment. Typical strength profiles show su rising from mud-line to 10 kPa to 15 kPa before dropping back to normally consolidated strengths of 3 kPa to 4 kPa by 1.5m to 2m depth. A Cam-shear device is used to better understand the mechanical behaviour of undisturbed crust samples under pipelines. Extremely variable peak and residual shear strengths are observed for a range of pipeline consolidation stresses and test shear rates, with residual strengths approximating zero. ESEM of undisturbed samples and wet-sieved samples from various core depths show the presence of numerous randomly-located groups of invertebrate faecal pellets. It is therefore proposed that the cause of strength variability during shear testing and, indeed, of the crust's origin, is the presence of random groups of faecal pellets within the sediment. © 2011 Taylor & Francis Group, London.

三峡水库成库期间鱼类空间分布的水声学研究

2007年4月18日～5月1日,利用SIMRAD EY60回声探测仪(又称鱼探仪)对三峡水库坝前到丰都干流以及9条主要支流进行了水声学探测。采用垂直探测结合"之"字形路线的方法对库区整个水体鱼类的分布状况进行了研究。调查水域长度约有600km,回波数据分成1232个片段进行分析。结果表明:在5m以下水层,体长大于6cm的鱼类在该区域平均密度为567.68尾/dam3,且鱼类分布不均匀。在巫山至奉节江段鱼类的密度最低,密度的平均值和标准误(mean±S.E)为(8.1±0.47)尾/dam3;在忠县到丰都江

无根萍、酵母菌和红螺菌的水质净化和抑藻作用

从2005年9月到2005年10月,利用莲花湖中的3个49m2,深度为1.5m的围隔进行生物水质净化和除藻研究。1#围隔为对照,2#围隔水体中加入无根萍,3#围隔水体中喷洒酵母菌和光合细菌。与1#围隔比较,2#围隔水面的无根萍的数目在300L×5×103 L-1,3#围隔的喷洒复合菌数目酵母菌(300L×4×105L-1)和红螺菌(300 L×8×108 L-1)。本实验结果表明:在30 d内,2#和3#围隔中的TP分别下降40%、25%;TN分别下降43%、16%;叶绿素含量分别下降51%、31%。透明

巢湖微囊藻和浮游甲壳动物昼夜垂直迁移的初步研究

2002年10月进行了巢湖微囊藻和几种优势浮游甲壳动物的昼夜垂直变化的研究,结果表明:微囊藻具有明显的昼夜垂直变化现象。白天上层水中的微囊藻密度显著高于下层水中,夜晚逐渐下沉使得下层水中的密度相对高于上层水。微囊藻与叶绿素a、水温、溶解氧和pH等均呈显著的正相关(p<0.01)。几种优势浮游甲壳动物的昼夜垂直迁移存在较大的差异。短尾秀体溞和角突网纹溞白天在下层水(1.5m和2.5m)中的密度较高,夜晚则倾向于在上层水(0m和0.5m)中活动。相反,卵形盘肠溞白天在上层水中密度较高,象鼻溞则在11:00和1

香溪河官庄坪库湾叶绿素a及初级生产力的分布特征

2005年2月—4月对三峡库区香溪河进行了定点初级生产力及相关影响因子的研究,分析了官庄坪库湾叶绿素a含量和初级生产力的时空分布特征。结果表明,叶绿素a含量、初级生产力在各水层的变化具有相同的周期性,均存在5个峰值,平均每个周期为7—10d左右,但两者不同步。官庄坪测站的真光层深度为10m左右,介于湖泊与海洋之间,光补偿点为4—5m。初级生产力最大值出现在水下0.5m处,并沿物理深度逐渐降低;叶绿素a含量最大值则出现在水下2m处。水温的垂直变化在后期差异明显,各水层日平均水温增量(ΔT/d)与平均毛初级生

五里湖深水区沉水植被重建策略探索

本文以菹草(PotamogetoncrispusL.)和伊乐藻(Elodeanuttallii)为材料,在不同水深条件下对沉水植物的生长进行了研究。结果表明:随着水深的增加,菹草和伊乐藻的茎伸长速度逐渐增大,但分支数或株数减少,最终植物生物量减少;菹草和伊乐藻种群能够建立的水深极限条件分别为:2倍SD和2.3倍SD。在冬季透明度为1.1-1.2m条件下,伊乐藻种群在2.5m水深处成功建立。高透明度(>1.1m)是五里湖深水区伊乐藻种群建立的关键条件。在此研究的基础上,本文探讨了重建五里湖深水区沉水植被的可

湿地中碱性磷酸酶的动力学特征与水生植物的关系

本文讨论了种植菹草 (PotamogetoncrispusL .)、水花生 (AlternanthearphiloxeroidesGriseb .)、紫背浮萍 (Spirodelapolyrhiza(L .)Schleid .)以及对照实验池 (12 .5m× 9.5m)过滤 (小于0 4 5 μm)与未过滤水样和沉积物中碱性磷酸酶的动力学特征及其分布 .水生植被能降低水样和表层沉积物酶的催化效率 ,抑制作用因植物的种类而异 ,且在未过滤水中表现得尤为突出 .因此 ,受抑制者多与较大的颗粒相联系 ,这一结