Age and growth of sailfish (Istiophorus platypterus) in waters off eastern Taiwan

Age and growth of sailfish (Istiophorus platypterus) in waters off eastern Taiwan were examined from counts of growth rings on cross sections of the fourth spine of the first dorsal fin. Length and weight data and the dorsal fin spines were collected monthly at the fishing port of Shinkang (southeast of Taiwan) from July 1998 to August 1999. In total, 1166 dorsal fins were collected, of which 1135 (97%) (699 males and 436 females) were aged successfully. Trends in the monthly mean marginal increment ratio indicated that growth rings are formed once a year. Two methods were used to back-calculate the length of presumed ages, and growth was described by using the standard von Bertalanffy growth function and the Richards function. The most reasonable and conservative description of growth assumes that length-at-age follows the Richards function and that the relationship between spine radius and lower jaw fork length (LJFL) follows a power function. Growth differed significantly between the sexes; females grew faster and reached larger sizes than did males. The maximum sizes in our sample were 232 cm LJFL for female and 221 cm LJFL for male.

鄂尔多斯高原主要灌丛群落与生境及生物多样性保育的研究

鄂尔多斯是我国北方半干旱区一个相对独立的自然单元和典型而十分敏感的生态过渡带．其植被随水分梯度的东西向变化明显．特殊的自然生态背景造就了灌木是该地区优势生活型植物的地位．从高原东部的典型草原到西部的草原化荒漠，灌丛群系的生态替代尤为明显，如从典型草原的小叶锦鸡儿、百里香群系，到荒漠化草原与草原化荒漠过渡带的狭叶锦鸡儿、藏锦鸡儿等群系，一直到草原化荒漠的红砂、四合木、沙冬青等灌丛群系，这种明显的生态替代反映了鄂尔多斯高原生态梯度变化的特点． 1.文根据野外调查和前人研究的资料，分析研究了该地区灌木资源的特点，区系的种类组成，生活生态习性和区系的地理成分，指出：鄂尔多斯高原灌木资源丰富多样，其中饲用灌木的价值尤为突出．本地区是我国半干旱地区及全球温带草原灌木多样性分布和起源的中心．是多样性丰富，种类集中分布的“灌木王国”，也是许多珍稀古老残遗种的“避难所”。 2.研究了灌木多样性的特点及其环境梯度变化对多样性的影响，研究表明：水分梯度变化是诸生态因子（海拔。地理坐标、年均温．最热月均温，最冷月均温．日照百分率、沙暴日数。风速等）中对生物多样性影响最大的因子，但其显著性偏低，这主要是群落草本层植物对群落多样性指数的影响较大，而人类过度放牧和破坏给灌丛群落的烙印远远超过了水分梯度变化的影响． 3.对高原荒漠化草原与草原化荒漠过渡带主要灌丛植被进行了DCA捧序和TWINSPAN分类，并作了环境解释，鄂尔多斯高原灌丛群落的分布格局主要受制于水分因子，此外土壤基质对一些群落的分布格局也起了支配作用，温度及其它因子对其影响不明显， 4.本文从水分生理生态和生态解剖两个方面论述了灌木长期适应严酷干旱胁迫的生态适应对策． 5.本文探讨了珍稀，濒危灌木种的保育策略，生物多样性的保育包括就地保护，迁地保护和持续利用三个方面的内容．人工植被的建立和经营管理有益于生物多样性的恢复和本地区灌木生物多样性的持续利用;由于鄂尔多斯地区灌木种类丰富、分布不均以及本地大规模的能源开发、人口压力和社会经济发展水平等褚因素的影响，不可能对灌木种类做到逐一的保育，建立灌木园是鄂尔多斯地区灌木生物多样性保育的最有效．最经济的手段和策略。

Mode control in vertical-cavity surface-emitting lasers by post-processing using focused ion-beaih etching

Single-mode emission is achieved in previously multimode gain-guided vertical-cavity surface-emitting lasers (VCSEL's) by localized modification of the mirror reflectivity using focused ion-beam etching. Reflectivity engineering is also demonstrated to suppress transverse mode emission in an oxide-confined device, reducing the spectral width from 1.2 nm to less than 0.5 nm.

一种液向色谱电位型检测器及其检测方法

本发明涉及日化领域及医药行业，具体讲是一种N-（乙基氨基）菊糖及其制备和应用。所述N-（乙基氨基）菊糖为式（1）所示，其中n的平均取值范围是10－35。制备方法将菊糖经卤代或磺酰氯酯化后与无水乙二胺在40-90℃条件下反应8－24 h，经纯化，即得到N-（乙基氨基）菊糖，所述无水乙二胺的摩尔量是菊糖的30至40倍。所得化合物可作为抗氧化剂本发明合成步骤简单，易于推广，所需设备及原料易得。本发明所得产品可广泛用于生物、医药、食品、化工等领域。