关于鱼的生长方程的研究──Ⅰ.鱼的生长方程的修正     

赵维谦 《海洋与湖沼》1994,(4)

指出vonBertalanffy生长公式的局限性在于公式导出时所用假设“鱼的体重增加量同体重的2／3次方成比例，减少量同体重成比例”的根据不充分；其不足之处在于解方程时将变量l误为鱼的体长。本文作了更为一般的假设，即鱼的体重增加量同体重的P次方成比例；减少量同体重的q次方成比例。进而通过严格的数学推导，得出鱼的更为一般的生长方程w=w∞[1-e－k(s-s0)]r，使vonBertalanffy生长公式是该方程的特殊情形．  相似文献   

南方鲇的鱼体能量密度及其预测模型   总被引：13，自引：0，他引：13  

曹振东  谢小军 《海洋与湖沼》2002,33(1):68-74

于1992年和1993年2－4月由嘉陵江收集的野生南方鲇雌、雄成鱼各20尾；1996年1－4月取得了不同摄食水平处理的幼鱼19尾，饥饿处理的幼鱼18尾，测定了这4个样本的鱼体能量密度及化学组成。结果表明，各样本能量密度均分别与干物质和脂肪含量呈显著的直线相关关系；幼鱼2个样本的能量密度与蛋白质含量的正相关关系也达到显著性，而雌、雄成鱼样本的能量密度分别与干物质（DM：％B．W．）的直线回归方程的协方差分析，可将雌雄成鱼群体的两个回归方程合并为公共的成鱼能量密度（EA：kJ/g）方程：EA＝1．67＋0．302DM；将不同营养状况幼鱼的两个回归方程合并为公共的幼鱼能量密度（D1：kJ／g）方程：EJ＝－2．26＋0．329DM。  相似文献   

Emotional labour/body work: The caring labours of migrants in the UK’s National Health Service     

S. Dyer  L. McDowell  A. Batnitzky 《Geoforum》2008,(6):2030-2038

The provision of care is an increasingly pressing issue in the Global North. With an ageing population and policies encouraging women into the labour market, there is a growing need for workers to undertake paid caring. This poses important and urgent questions about the social organisation of labour markets. Care work typically is low paid and undertaken in precarious, informal, or temporary situations. Many posts are filled by economic migrants, raising concerns about a care deficit in sending countries. In this paper we examine the ‘caring work’ undertaken by migrant workers in a West London Hospital. We employ a twofold characterisation of caring work. Like other bottom-end service sector work, this work is characterised by the face-to-face ‘emotional labour’. However, it also requires ‘body work’: close and often intimate physical contact between carers and those they care for. We argue that both of these aspects are important in understanding how caring work is constructed as poorly regarded and low paid. We show how these features play out in particular ways for migrant workers employed in such caring work.  相似文献   

Allometry and body length of abelisauroid theropods: Pycnonemosaurus nevesi is the new king     

《Cretaceous Research》2017

Abelisauroid dinosaurs normally reached an average body length (BL) of 5–9 m, but there are controversies due to the incomplete or fragmentary nature of most specimens. For Ekrixinatosaurus, for example, BL was estimated as 10–11 m or 7–8 m; for Pycnonemosaurus it was proposed 7–8 m, however its preserved bones are larger than any other described abelisauroid. The lack of a consistent methodology complicates comparisons of estimated BL, so we reevaluated the estimative for the seven most complete specimens of abelisauroids and compared the values against 40 measurements from the skull, vertebrae and appendicular elements using bivariate equations. It allowed estimating the BL of other 30, less complete, specimens of abelisauroids and to evaluate the allometric scaling of the skeletal parts. Strong correlations (R² > 0.96) were obtained for all vertebrae and hindlimb measurements, as well as skull height, and length of skull roof, lacrimal–squamosal, scapulocoracoid and humerus; other skull and forelimb measurements present weak correlation due to extreme morphological transformations observed in Abelisauridae and were not adequate for BL estimation. Abelisauroids gradually increased in size during evolution: the mean BL was 3.3 ± 2.5 m for basal abelisauroids and Noasauridae, 5.4 ± 1.8 m for basal Brachyrostra and Majungasauridae, and 7.1 ± 2.1 m for Furileusaura. Despite this variation, diversity of BL on each geographic region and stratigraphic epoch was relatively constant (BL usually varied from 4 to 8 m). The smallest noasaurid and abelisaurid are, respectively, Velocisaurus (1.5 ± 0.1 m) and Genusaurus (3.6 ± 0.0 m). The largest abelisaurids is Pycnonemosaurus nevesi (8.9 ± 0.3 m) followed by Carnotaurus (7.8 ± 0.3 m), Abelisaurus (7.4 ± 0.7 m) and Ekrixinatosaurus (7.4 ± 0.8 m). Skull measurement scale negatively at a similar rate but the height scales almost isometrically and the skull roof length scales more negatively; this probably caused a bending on the skull that may explain the upward orientation of the snout in large taxa.  相似文献   

云南中甸热林岩体的成矿作用     

伍建兢  杨丽梅  吴俊 《云南地质》2011,30(2):216-219

热林矿区的热林复式花岗岩体,从早至晚、边部到中部,分出4个侵入体组成的同源岩浆细粒-中粒-斑状结构演化系列。成矿作用有差异,从而形成各具特色的矿床。  相似文献   

羊拉铜矿里农矿段与路农矿段接合部找矿方向     

方中有  李波  李红飞  王胜兰 《云南地质》2011,30(4):401-403

里农段与路农段接合部主矿体向北西倾,且沿倾向方向品位提高,沿北西方向追索、布置工程可望取得突破。  相似文献   

日本鳗鲡(Anguilla japonica)对日本沼虾(Macrobrachium nipponense)的捕食效应   总被引：1，自引：0，他引：1       下载免费PDF全文

王志铮  杨磊  朱卫东  王海强  施建军 《海洋与湖沼》2011,42(1):107-113

采用捕食者.猎物间捕食效应研究方法,研究了日本鳗鲡对3种体长规格日本沼虾的捕食效应.结果表明:(1)日本鳗鲡与日本沼虾的主要活动时段均为17:00至翌日5:00,期间日本沼虾的活动量随其体长规格的增大而减少,日本鳗鲡的主要捕食时段为0:00-5:00,其对体长2.4cm左右的日本沼虾有较强的追捕行为;(2)日本鳗鲡对日...  相似文献   

日本沼虾（Macrobrachiumnipponensis）形态性状对体重的影响效应   总被引：6，自引：2，他引：4  

王志铮  吴一挺  杨磊  朱卫东 《海洋与湖沼》2011,42(4):612-618

选取日本沼虾5月龄同生群雌、雄虾各90尾,分别测量其体重、体长、头胸甲长、胸宽、胸高、腹节长、腹节宽、腹节高、尾节长、尾节宽、尾节高、眼窝距、额剑长等13个表型性状,并采用相关分析、通径分析和偏回归分析等方法定量研究了雌、雄个体形态性状对体重的影响效应。结果表明：（11雌、雄测定群体各形态性状测量值间均存在显著的性别差...  相似文献