A lagosta de profundidade Palinurus delagoae da costa de Moçambique

Catch and effort data and some biological characteristics of the deep water spiny lobster P. delagoae were presented.

Dol net fishery off Nawabunder (Gujarat)

Extimated catch of 6,484.9; 3,505.6 and 4,797.7 t of fishes were landed at Nawabunder in 'dol.' net during 1976-77, 1977-78 and 1978-1979 respectively. There has been an increasing trend in effort and decline in catch and catch rate. The catch rate came down from 174.8 kg in 1976-77 to 84 kg in 1978-79. The detailed studies on the catch composition revealed that the Bombay duck formed about 68.6-77% of the total catch. The other important constituents being Coilia dussumieri 1.5-9.2%, ribbon fish 3.0-6.5%, non-penaeid prawn, namely, Acetus indicus, Nematopalaemon tenuipes and Hippolysmata ensirostris together formed about 6.1-13.7% and penaied prawns 1.5-3.1% of the total dol net landings. In addition, quality fishes such as ghol, warn, pomfret and catfishes were also landed in considerable quantities. The landings of ghol are on the increase from 4.9 t in 1976-77 to 59 t in 1978-79. Large number of juveniles of economically important fishes namely, Harpodon nehereus, Pampus argenteus, Trichiurus lepturus and Ilisha filigera have been observed in the catch particularly during February-May. The destructive nature of the gear has been commented along with the suggestions for regulation of the fishery.

CRM in the Philippines: Lessons learned

Philippine coastal communities can become capable fishery resource managers and that their management practices can become largely self-sustaining if the project approach focuses on assisting fishermen to learn how to help themselves. Community organization is an essential part of the process and should not be viewed as an end product in itself. There are also no quick fixes, and projects require a complex array of activities if large numbers of coastal residents are to be assisted. In some of these projects, the control of illegal fishing combined with limiting of commercial fishing to offshore areas and good coastal habitat management resulted in a doubling of daily fish catch and income for small-scale fishermen. However, even with the best of management, the total fishery harvest is limited and further increases in individual fishing income can only come from reducing total fishing effort. This will require a system of control on access to the resource to limit the number and kind of fishing gears and to divide the resource equitably. Assisting coastal communities to devise and implement realistic equitable access controls is the major challenge facing coastal resource co-management.

Reproductive biology of Catla catla in the Udawalawe reservoir, Sri Lanka

The reproductive biology of Catla catla (Hamilton-Buchanan) in the Udawalawe reservoir was studied from June 2007 to December 2008. Samples of eggs from Indian major carp C. catla were collected from fish landed in the reservoir and analysed in the laboratory to assess the reproductive characteristics. C. catla. Cirrhinus mrigala, exotic Cichlids and Labeo rohita accounted for 62.2%, 21.0%, 12% and 1.0% respectively of the total landings in the Udawalawe reservoir during the study period. Gonads of C. catla were collected in the field and examined in the laboratory to determine the stage of maturity and fecundity. Data on fish length and gonad weight were collected to estimate the gonado-somatic indices (OSI). Landed catches were also examined in the field to determine the sex ratio of C. catla in the catch and was found to be 1:5.6 male to female. Results of fecundity estimates revealed that C. catla females in the Udawalwe reservoir were fully mature in June and October of the year. From the monthly variation of OSI, two recruitment pulses per year were evident. The length of the body at first maturity in female C. catla in the Udawalwe reservoir was estimated to be 74.2 cm.

The potential for co-management in fisheries

Concerns have been raised over the sustainability of the fisheries resource base of Lake Victoria for some time. The draft National Fisheries Policy states: "The key issues in the fisheries sector are resource depletion through overfishing aggravated by use of destructive fishing gear and methods" (MAAIF 2000). A fishery is said to be degraded if any or all of the indicators begin to show including decline in catches from the fishery, higher proportion of immature fish in the catch and reduction in the species composition of the catch. Inadequate implementation of fisheries management is considered the main cause of resource degradation. One of the factors identified as constraints to fisheries management has been lack of involvement of the resource users.

Phytoremediation of triazophos by Canna indica Linn. in a hydroponic system

The phytoremediation of triazophos (O, O-diethyl-O-(1-phenyl-1, 2, 4-triazole-3-base) sulfur phosphate, TAP) by Canna indica Linn. in a hydroponic system was studied. After 21 d of exposure, the removal kinetic constant (K) of TAP was 0.0229-0.0339 d(-1) and the removal percentage of TAP was 41-55% in the plant system and the K and removal percentage of TAP were about 0.002 d(-1) and 1%, respectively, in darkness and disinfected control. However, the K and removal percentage of TAP were 0.006 d(-1) and approximately 11%, respectively, in the treatment with eluate from the media of constructed wetland. The contribution of plant to the remediation of TAP was 74% and C. indica played the most important role in the hydroponic system. Under the stress of TAP and without inorganic phosphorus nutrient, the activity of phosphatase in the plant system increased and phytodegradation was observed. The production and release of phosphatase is seen as the key mechanism for C. indica to degrade TAP. C. indica, which showed the potential of phytoremediation of TAP, and is commonly used in constructed wetland, so the technique of phytoremediation of TAP from contaminated water can be developed with the combination of constructed wetland.

The research of phosphorus of Xiangxi River nearby the Three Gorges, China

The Xiangxi River is the first middling tributary of the Changjiang River near the Three Gorges Dam. The River is subject to phosphorus pollution mainly from industrial wastewater. As the water quality of the Xiangxi River could directly influence the water quality of the Three Gorges Reservoir, the research on phosphorus levels and its change in the sediment profile of the Xiangxi River could provide useful information in the dynamic changes in the system, thereby offering options for mitigative measures. Water and sediment samples from lower reaches of Xiangxi River were collected and the different forms of phosphorus in sediments of the Xiangxi River were studied. The concentrations of total phosphorus in sediment ranged from 757.67 to 1438.54 mg/kg. Inorganic phosphorus concentrations ranged from 684.63 to 1055.58 mg/kg. Phosphorus contamination was serious in some parts of the Xiangxi River. With an average concentration of 635.17 mg/kg, calcium-bound phosphorus is the main form among different inorganic phosphorus forms. Labile phosphorus and iron/aluminum-bound phosphorus measured 3.40, 0.05and 35.28 mg/kg, respectively. The mobilization potential of phosphorus of sediments was studied through adsorption and release experiments. The equilibrium concentration of phosphorus adsorption and release was around 0.1 mg/L. The initial concentrations of phosphorus in the overlying water and the sediments have obvious effect on phosphorus mobilization potential. In addition, the release rate of phosphorus in sediment increased with water depth.

Linear multimodal actuation through discrete coupling

Due to technological limitations, robot actuators are often designed for specific tasks with narrow performance goals, whereas a wide range of behaviors is necessary for autonomous robots in uncertain complex environments. In an effort to increase the versatility of actuators, we introduce a new concept of multimodal actuation (MMA) that employs dynamic coupling in the form of clutches and brakes to change its mode of operation. The dynamic coupling allows motors and passive elements such as springs to be engaged and disengaged within a single actuator. We apply the concept to a linear series elastic actuator which uses friction brakes controlled online for the dynamic coupling. With this prototype, we are able to demonstrate several modes of operation including stiff position control, series elastic actuation as well as the possibility to store and release energy in a controlled manner for explosive tasks such as jumping. In this paper, we model the proposed concept of actuation and show a systematic performance analysis of the physical prototype that we developed in our laboratory. © 1996-2012 IEEE.

Crack-free GaN/Si(111) epitaxial layers grown with InAlGaN alloy as compliant interlayer by metalorganic chemical vapor deposition

A new method is demonstrated to be effective in reducing mismatch-induced tensile stress and suppressing the formation of cracks by inserting InAlGaN interlayers during the growth of GaN upon Si (1 1 1) substrate. Compared with GaN film without quaternary interlayer, GaN layer grown on InAlGaN compliant layers shows a five times brighter integrated PL intensity and a (0 0 0 2) High-resolution X-ray diffraction (HRXRD) curve width of 18 arcmin. Its chi(min), derived from Rutherford backscattering spectrometry (RBS), is about 2.0%, which means that the crystalline quality of this layer is very good. Quaternary InAlGaN layers, which are used as buffer layers firstly, can play a compliant role to endure the large mismatch-induced stress and reduce cracks during the growth of GaN epitaxy. The mechanisms leading to crack density reduction are investigated and results show that the phase immiscibility and the weak In-N bond make interlayer to offer tenability in the lattice parameters and release the thermal stress. (c) 2005 Elsevier B.V. All rights reserved.

肥料氮在土壤-作物系统中的转化与释放规律

本文以公主岭市长期定位监测基地的黑土为研究对象，通过15N同位素标记盆栽试验，系统研究了化肥及其配施玉米秸秆处理土壤不同形态氮库的容量特性、释放规律及其对作物的持续供氮能力。结果表明： 标记化肥氮施入土壤，连续三个生长季主要以有机氮的形式残留于土壤中，其次是固定态铵，无机氮最小。新形成土壤有机氮和“新固定”的固定态铵活性较高，极易释放供作物吸收利用，连续三季作物土壤固定态铵的净释放率最高，氨基酸氮次之，有机氮最低。与土壤有机氮库相比，土壤无机氮库中标记肥料氮的残留率较低，高量氮肥处理残留率高于低量氮肥处理，与单施化肥相比，化肥配施玉米秸秆降低了标记肥料氮在土壤无机氮库中的残留，说明高量氮肥的施用会增加其在无机氮库中的残留，化肥与有机物料配合施用能够促进无机氮肥向土壤有机氮的转化，从而避免无机氮大量积累而造成氮素损失。 标记氮肥在土壤中的残留率随作物生长季的增加而降低，经过连续三季作物的吸收利用，其在土壤中的残留率平均为15.8%；而作物对标记肥料氮的利用率和标记肥料氮的损失率随着作物生长季的增加而增加，至第三季作物成熟期，作物对标记肥料氮的利用率平均为61.1%，标记肥料氮的损失率平均为23.1%。在单施化肥处理中，高量氮肥的施用降低了标记肥料氮在土壤中的残留率，增加了氮素损失率；与单施化肥处理相比，化肥配施玉米秸秆能明显增加标记肥料氮在土壤和作物中的回收率，降低氮素损失率，从而说明通过施入有机物料玉米秸秆合理调节土壤中C源和N素营养的施用比例可以达到增加氮肥在土壤中的残留率，提高氮肥利用率的目的。

Experimental study of Electro-elasto-capillarity:Electric field driven unwrapping of water drop with elastic film

<正>Elasto-capillarity has drawn much of scientists' attention in the past several years.By inducing electric field into the droplet,the encapsulation and release procedure can be realized and we call it electro-elasto-capillarity(EEC).EEC offers a novel method for micro-scale actuation and self-assemble of moveable devices.It also provides a good candidate for the drug delivery at micro- or nanoscale.

Swelling behaviour of alginate-chitosan microcapsules prepared by external gelation or internal gelation technology

Swelling behaviour is one of the important properties for microcapsules made by hydrogels, which always affects the diffusion and release of drugs when the microcapsules are applied in drug delivery systems. In this paper, alginate-chitosan microcapsules were prepared by different technologies called external or internal gelation process respectively. With the volume swelling degree (S-w) as an index, the effect of properties of chitosan on the swelling behaviour of both microcapsules was investigated. It was demonstrated that the microcapsules with low molecular weight and high concentration of chitosan gave rise to low S-w. Considering the need of maintaining drug activity and drug loading, neutral pH and short gelation time were favorable. It was also noticed that S-w of internal gelation microcapsules was lower than that of external gelation microcapsules, which was interpreted by the structure analysis of internal or external gelation Ca-alginate beads with the aid of confocal laser scanning microscope. (C) 2004 Elsevier Ltd. All rights reserved.

Charge transport in accumulation layers of organic heterojunctions

We studied the charge transport in organic heterojunction films consisting of copper phthalocyanine (CuPc) and copper hexadecafluorophthalocyanine (F16CuPc). The heterojunction effect between CuPc and F16CuPc induced high-density carriers at both sides of heterojunction. The Hall effect was observed at room temperature, which demonstrated the existence of free carriers and their delocalized transport under heterojunction effect. The Hall mobility of 1.2 cm(2)/V s for holes and 2.4 cm(2)/V s for electrons indicated that the transport capability of the heterojunction films is comparable to single crystals. The transport process was further explained by the multiple trap-and-release model according to the temperature dependence of conduction.

Potassium-Lead-Switched G-Quadruplexes: A New Class of DNA Logic Gates

A cation-driven allosteric G-quadruplex DNAzyme (PW17) was utilized to devise a conceptually new class of DNA logic gate based on cation-tuned ligand binding and release. K+ favors the binding of hemin to parallel-stranded PW17, thereby promoting the DNAzyme activity, whereas Pb2+ induces PW17 to undergo a parallel-to-antiparallel conformation transition and thus drives hemin to release from the G-quadruplex, deactivating the DNAzyme. Such a K+-Pb2+ switched G-quadruplex, in fact, functions as a two-input INHIBIT logic gate. With the introduction of another input EDTA, this G-quadruplex can be further utilized to construct a reversibly operated IMPLICATION gate.

水下机器人锁紧释放技术综述

叙述了锁紧释放系统在水下机器人上的应用,说明了锁紧释放装置是控制水下机器人作业的重要手段。分析了天津大学研制的水下机器人解锁释放搭载体和设备、半埋雷打捞装置夹紧爪和美国某型号武器水下发射装置完成预定任务的工作原理和结构特点。归纳总结了水下大型构件锁紧释放系统设计中应着重考虑的问题。讨论了动力源形式的选择和力(矩)裕度分析、支撑与紧固点的选择、锁紧与释放形式的选择和实现、密封技术等四项锁紧释放机构的关键技术。