Growth, mortality and recruitment of Nile perch Lates niloticus (L. Centropomidae) in the Nyanza Gulf of Lake Victoria: an evaluation update

A reassessment of the estimates of growth, mortality and recruitment patterns of Nile Perch, Lates niloticus was made based on data from commercial landings collected during the Catch Assessment Survey Programme. Two sets of length frequency data, one each from beach seining and hook and line fisheries, were analyzed. Values of L8 = 169 and 230 (cm TL) and K= 0.18 yr-1 and 0.195 yr-1 were obtained. The total mortality estimates from the catch curve analysis were Z = 0.72 yr-1 and 0.94 yr-1, respectively, with a natural mortality M of about 0.35 for a mean environmental temperature of 27oC. The highest peak for recruitment was in November, December and January with a minor one in June, indicating recruitment of two cohorts per year. These results are discussed and compared to previously available information on L. niloticus in Lake Victoria.

Developpement de la peche artisanale dans les eaux Burundaises du Lac Tanganyika

A light fishery for "Ndagala" (Strolothrissa tanganicae) has been practised for many years on Lake Tanganyika. Initially this had a low catch rate, but has since been developed by the introduction of an artisanal fishery unit based on the catamaran. A unit consists of a pair of metal canoes joined together. The fish are attracted by three lights mounted on the structure, and are caught with a pyramid-shaped lift net. Selected beaches have been reserved for the artisanal fishery and the numher of units operating has increased from 12 in 1957 to 538 in 1972. The mean annual catch per unit is 11,000 kg, which is not sufficient for the fishery to be economic. However, prediction of a possible mean catch as high as 40 tons year encouraged the Burundi Government to launch a project with help from the Freedom from Hunger Campaign. This was designed to develop the fishery by the creation of artisanal fishing centres, and to make available a large number of fully equipped catamarans which could be paid for by a system of hire-purchase. The success of the project has illustrated that the furnishing of adequate equipment can bring about a transformation of the traditional fishery.

表达lac和glk基因的蓝藻的异养生长

将来自Brucellaabortus的葡萄糖激酶基因glk和大肠杆菌乳糖操纵子基因lacZYA装置于蓝藻glnA启动子下游 ,以广宿主质粒导入 3种蓝藻。基因的表达通过 β 半乳糖苷酶和葡糖激酶活性测定得到确证。基因工程藻株均获得了利用乳糖异养生长的能力。集胞藻 6 80 3转基因株可在光照加DCMU的条件下利用乳糖生长 ,而鱼腥藻转基因株依赖乳糖可在完全黑暗条件下生长 ,并可在黑暗或加DCMU条件下诱导产生异形胞

Theoretical Investigation of LaC~n and La_2C~n(n=-1,0,+1)Clusters

用密度泛函方法研究了ＬａＣｎ及Ｌａ２Ｃｎ（ｎ＝－１，０，＋１）分子簇的结构和稳定性．对Ｌａ２Ｃｎ体系，提出了两种可能构型，其中一种具有Ｃ２ｖ对称性，另一种具有Ｄ∞ｈ对称性．计算结果表明，对Ｌａ２Ｃｎ，当ｎ＝＋１，－１时，线状结构最稳定，并且在ｎ＝＋１时，Ｃ２ｖ结构极不稳定有收敛向线状结构的趋势．而当ｎ＝０时，Ｃ２ｖ结构最稳定．最后还计算了ＬａＣ和Ｌａ２Ｃ分子簇的电子亲和势和离化能.

« Messire Lancelot du Lac » de « GAULTIER MOAP ». « Messire Lancelot du Lac » de « GAULTIER MOAP ».

Le f. 100 manque.

« Messire Lancelot du Lac » de « GAULTIER MOAP ». « Messire Lancelot du Lac » de « GAULTIER MOAP ».

Le f. 100 manque.

« Messire Lancelot du Lac » de « GAULTIER MOAP ». « Messire Lancelot du Lac » de « GAULTIER MOAP ».

Le f. 100 manque.

Lago d'Averno : [vue générale du lac d'Averne près de Pouzzoles] : [peinture]

Collectionneur : Lesouëf, Auguste (1829-1906)

R. Casino del Fusaro : [vue générale du lac] : [peinture]

Collectionneur : Lesouëf, Auguste (1829-1906)

Lancelot du Lac [par GAUTIER MAP].

Commençant par : «... nois negée et si li out aparellée à sa chevalerie robe blanche de samit, cote et mantel... » et finissant par : «... conquier, damoisele, nos en aurons... helmes et cil chevaliers a... » . Incomplet an commencement et à la fin ; le dernier feuillet est en partie effacé.

Roman de Lancelot du Lac, Quête du S. Graal et mort d'Artus, par GAUTIER MAP.

Contient : «... l'assemblée qui lors i fu la veille de Pantecouste. Explicit. Ci fenist mestre Gautier Map son livre et commance le Galaad. (Fol. 152.) A la veille de Pantecouste quant li compaignon de la Table ronde... » (Incomplet. de la fin.) — Miniatures