La reproducción de la merluza en el Mar Argentino (Merlucciidae, Meluccius merluccius hubbsi) : 2. La reproducción de la merluza y su relación con otros aspectos biológicos de la especie

The paper deals with the spawning cycle of the hake, Merluccius merluccius hubbsi in the fishing area of the Argentine fleet, SW Atlantic (35°- 46° L. S.: 53°- 63° L.W.; 30-160 fathoms depth). It was made on the basis of the weekly sampling of the commercial catch in the period January 1965 - March 1968. The results have been compared with those of the exploratory surveys made by the United Nations Fisheries Development Program (República Argentina - FAO). The histological study, which was made with 741 specimens, was most intensive in females than in males. The results have been compared with the sexual stage determinations of both sexes in the total samples during the period before mentioned. The conclusions are: 1. The analysis of the ovocytes frequency distributions showed a period of resting or slow recuperation (April - August) with a mode of 120 ~k and one of rapid transformation (October - December) from 120 μ tíll 830 ~k. After December it appears again the mode of 120 ~k which indicated the reserve stock. 2. The maturity factor shows in both sexes a period of low values , 0,52 to 2% (April - September) and, another with higher values (October - March). In the first period the values are concentrated, while in the second one a large dispersion is observed produced by the rapidity of the growth process of the gonads. It is more evident between November and December. 3. The liver weight variations, compared with the degree of ingestion and the values of the maturity factor, in time, demonstrated that: a) after two periods of abundant ingestion (March - April and October- November) there are two increases of the liver index; b) the increase of the Iiver index has a direct relation to the maturity factor; c) at the end of the summer season, when the values of the maturity factor decrease, those of the liver index are still high. This demonstrates that the hake does not arrive exhausted at the end of the spawning season and that a rapid recuperation for a new spawning by part of the stock is possible. 4. Females predominate in the samples during most of the year. In the period October - December, when sexual activation occurs, as it is demonstrated by the high values of the maturity factor, proportions are nearly 1 :1, and males at times are more numerous than females. 5. The analisys of the advaneed maturity stages, in relation to total length shows that in the hake, Iike in other fishes, the largest ones mature first. This applies for both sexes. 6. The study of the maturity factor values and the sexual stages of the samples allows the recognition of two spawning periods, the main one in summer (October - March) and another in winter (June - July). 7. Part of the summer spawners, with a rapid recuperation, should be able to spawn again in winter. This indicates that the hake population, acording to our samples, has two different possibilities of spawning. 8. After analysis of the frequency percentages composition of mature specimens it is concluded that during the summer season, when hake is fished in shallow waters and in a wide area (38°– 43° L.S.) the fleet is fishing on the spawning stocks. Some winter spawners specimens have been found at 37°- 38° L.S. and in waters of more than 100 fathoms depth. 9. A new maturity scale of seven stages is proposed, instead of the one of six stages now in use. The new added stage corresponds to the postspawners during its resting period.

草鱼肠型点状气单胞菌的分离和鉴定

从发病草鱼中分离出1株细菌。经形态学、染色特性、溶血性和理化特性鉴定为肠型点状气单胞菌。致病性试验中小白鼠和草鱼分别于48h和72h内全部死亡,并从小白鼠和草鱼中回收到分离菌。药敏试验表明,该菌对常用抗生素呈不同程度的敏感性。

柱状黄杆菌外膜蛋白的比较蛋白质组学研究

为了鉴定柱状黄杆菌(Flavobacterium columnare)的毒力相关因子,利用蛋白质组学方法分析了强毒株G4R3和弱毒株G18的外膜蛋白。双向电泳结合图像分析,共发现了8个差异表达的蛋白点。经过胶内酶解和质谱分析,其中的1个蛋白点被鉴定为LemA蛋白,它可能是柱状黄杆菌的一种毒力因子。

八角枫挥发油化学成分研究

八角枫是八角枫科八角枫属药用植物 ,分布较广。用气相色谱 /质谱 /计算机联用技术 ( GC/MS/DS)分析了水蒸气蒸馏得到的八角枫挥发油 ,鉴定出 5 9种化学成分 ,其主要成分为 :1 ,8-桉叶素 ( 43.32 5 % )、β-侧柏烯 ( 1 0 .71 3% )、丁香酚甲醚 ( 7.0 88% )、α-松油醇( 7.0 1 7% )、α-蒎烯 ( 5 .830 % )等 5种化合物。被鉴定的 5 9种成分 ,共占挥发油总量的97.0 4 %。

湖北汉阳沉湖泛区浮游物的现存量与化学组成

本文报道了武汉市汉阳县沉湖泛区1983年5至9月浮游物(eston)的现存量与化学组成的动态,并根据该泛区的生态特征,分别对枯水期、灌江期和丰水期浮游物的干重(DW)、无灰干重(AFDW)、灰分重(Ash)、碳(C)和氮(N)量的变动特性进行了比较研究,而且还在此基础上,进一步探讨了评价浮游物营养质量的指标。沉湖泛区1983年5至9月浮游物干重为5.24mg/L,其中无灰干重为2.55mg/L,灰分重为2.69mg/L,它们均以灌江初期为高;碳、氮量分别为0.830和0.193mg/L,前者高峰出现在丰水

High-order detached eddy simulation, zonal LES and URANS of cavity and labyrinth seal flows

Hybrid numerical large eddy simulation (NLES), detached eddy simulation (DES) and URANS methods are assessed on a cavity and a labyrinth seal geometry. A high sixth-order discretization scheme is used and is validated using the test case of a two-dimensional vortex. The hybrid approach adopts a new blending function. For the URANS simulations, the flow within the cavity remains steady, and the results show significant variation between models. Surprisingly, low levels of resolved turbulence are observed in the cavity for the DES simulation, and the cavity shear layer remains two dimensional. The hybrid RANS-NLES approach does not suffer from this trait.For the labyrinth seal, both the URANS and DES approaches give low levels of resolved turbulence. The zonal Hamilton-Jacobi approach on the other had given significantly more resolved content. Both DES and hybrid RANS-NLES give good agreement with the experimentally measured velocity profiles. Again, there is significant variation between the URANS models, and swirl velocities are overpredicted. © 2013 John Wiley & Sons, Ltd.

Numerical study of a high-resolution far-field scanning optical microscope via a surface plasmon-modulated light source

In this paper, we analyze light transmission through a single subwavelength slit surrounded by periodic grooves in layered films consisting of An and dielectric material. A subwavelength grating is scanned numerically by the finite difference time domain method in two dimensions. The results show that the transmission field can be confined to a spot with subwavelength width in the far field and can be useful in the application of a high-resolution far-field scanning optical microscope.

共面紧凑型微波光子晶体在共面波导中的应用

提出一种地平面刻蚀共面紧凑型微波光子晶体(PBG)的共面波导结构,介绍了微波光子晶体的基本单元结构,并设计出具有90°弯折的共面波导样品.使用矢量网络分析仪测试该结构的散射参数,测量结果显示,其传输特性比普通的共面波导在高频部分具有较大的提高.同时,相比于传统的三维微波光子晶体,该结构具有导体损耗小,加工工艺简单,便于应用于光电封装和单片微波集成电路的特点.

双异质外延Si/Al_2O_3/Si薄膜制作的CMOS器件

报道了利用高真空MOCVD外延生长γ氧化铝的技术和利用SOS CMOS的成熟工艺制作双异质外延Si/γ-Al2O3/Si单晶薄膜以及用其研制Si/γ-Al2O3/Si CMOS场效应晶体管、Si/γ-Al2O3/Si CMOS集成电路的初步结果.

Growth of Cubic GaN by MOCVD at High Temperature

High quality cubic GaN (c-GaN) is grown by metalorganic vapor deposition (MOCVD) at an increased growth temperature of 900 ℃, with the growth rate of 1.6 μm/h. The full width at half maximum (FWHM) of room temperature photoluminescence (PL) for the high temperature grown GaN film is 48meV. It is smaller than that of the sample grown at 830 ℃. In X-ray diffraction (XRD) measurement, the high temperature grown GaN shows a (002) peak at 20° with a FWHM of 21'. It can be concluded that, although c-GaN is of metastable phase, high growth temperature is still beneficial to the improvement in its crystal quality. The relationship between the growth rate and growth temperature is also discussed.