论青少年体质健康的耗散结构*     

余良芬  吴本连 《上海交通大学学报(农业科学版)》2015,(1):36-39

目的：从耗散结构理论的角度研究解决我国青少年体质健康普通下降的严重问题，对解决我国青少年体质健康问题不仅具有独特的理论价值，而且具有显著的实践意义。方法：理论思辨法和逻辑分析法。结论：1.青少年体质健康普通下降的重要原因是其系统的耗散结构无法形成；2.解决青少年体质健康问题的重要途径在于促进其系统的耗散结构形成；3.开放性,远离平衡与非线性是青少年体质健康系统形成耗散结构的前提；4.满足青少年自我实现的愿望和体育锻炼的需求是青少年体质健康系统能够形成耗散结构的关键。  相似文献   

油松木材幼龄期与株内幼龄材分布   总被引：6，自引：0，他引：6  

徐有明 《华中农业大学学报》1992,11(4):382-387

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Effects of pyriproxyfen, a juvenile hormone analog, on development of the mealworm, Tenebrio molitor     

N. Aribi  S. Lakbar  N. Soltani 《Pesticide biochemistry and physiology》2006,84(1):55-62

Pyriproxyfen, an analog of the juvenile hormone (JH) in insects, has been evaluated in vivo and in vitro on an important stored product pest, the mealworm Tenebrio molitor. On newly ecdysed pupae, this insect growth regulator (IGR) was applied topically (at 0.10 and 0.20 μg/insect). Enzyme immunoassay measurements showed a decrease of the ecdysteroid titer in the hemolymph of treated specimens. In addition, the treatment induced an increase of the protein concentration in the hemolymph, however, there was no significant effect on the protein band pattern. Using in vitro pupal integument explant cultures, pyriproxyfen (at 1 and 10 μM in the medium) caused a significant inhibition of ecdysteroid amounts and of the thickness of new cuticle secreted. These new results are discussed in relation to the physiology of this IGR with a JH action.  相似文献   

兴城现代渔业园区可持续发展的几点建议   总被引：1，自引：0，他引：1  

孔维军 《水产科学》2006,25(11):593-594

几年来,在省、市海洋与渔业主管部门亲切关怀和正确领导下,兴城现代渔业园区的养殖面积由2002年的0.8×10 4 m 2发展到2005年的3.0×10 5m 2,园区的养殖场家达到80户,年产大菱鲆商品鱼2000 t以上,年产值达1.2亿元,实现利润0.5亿元,已成为辽宁省的大菱鲆养殖基地.但是,随着近两年养殖规模快速发展,井盐水供不应求、鱼苗供求矛盾等问题也逐渐显露出来,这势必将影响和阻碍园区的可持续发展.  相似文献   

Effect of electrical stunning at slaughter on the quality of farmed turbot (Psetta maxima)     

Toby G Knowles  Steve N Brown  Paul D Warriss  Jeff Lines  Ambrose Tinarwo  Marta Sendon 《Aquaculture Research》2008,39(16):1731-1738

Food quality aspects of farmed turbot (Psetta maxima) were compared following two methods of slaughter: the current commercial method, by immersion in an ice slurry, which is then dewatered after approximately 20 min, or by first humanely, electrically stunning the fish using a prototype commercial stunner, before immersion in an ice slurry, which is dewatered after 20 min. Quality was assessed for up to 10 days of storage on ice following slaughter. No differences were found between the slaughter methods in terms of an overall carcass quality: overall appearance, haemorrhage, damage, burst gall bladder, staining of the body cavity by leakage from the gut or damage to the spine. No detectable difference was found between the treatments using the industry standard freshness scoring system, the Quality Index Method. Both groups of fish were classified as ‘Fresh’ after 10 days of storage on ice. Using objective measurements of colour, no differences between fish from either treatment were found in fillet colour. Changes in flesh pH were similar in electrically stunned and traditionally killed fish with a mean pH (±SE) at 2 h post‐mortem of 6.80±0.027 declining to 6.44±0.032 at 24 h post‐mortem. Humane electrical stunning of turbot at slaughter neither detectably improved nor decreased product quality as measured between 1 and 10 days of storage on ice.  相似文献   

Influence of several non‐nutrient additives on nonspecific immunity and growth of juvenile turbot,Scophthalmus maximus L.     

Y. LI  Y.J. WANG  L. WANG  K.Y. JIANG 《Aquaculture Nutrition》2008,14(5):387-395

The effects of three non‐nutrient additives on nonspecific immunity and growth of juvenile turbot (Scophthalmus maximus L.) were studied in this feeding experiment. The five treatments are basal diet alone, basal diets containing three different additives [0.4 g kg^?1 of xylo‐oligosaccharides (XOS), 1.3 g kg ^?1 of yeast cell wall and 0.8 g kg ^?1 of bile acids] individually or in combination. Two hundred and twenty‐five turbots (average initial weight 151.3 ± 11.3 g) were randomly allotted in five treatments with three replicates within each treatment in a 72‐day period. Comparing with basal diet group, activities of C3, C4, phagocyte, lysozyme, specific growth rate and feed conversion rate in yeast cell wall, XOS and the combined groups was enhanced significantly (P < 0.05); however, these parameters in bile acid groups were increased slightly (P > 0.05) except for phagocyte (P < 0.05); superoxide dismutase activity in additive groups was not significantly increased (P > 0.05) except for the combined group (P < 0.05). In conclusion, supplementation of yeast cell wall and XOS enhanced the nonspecific immunity of juvenile turbot. Synergistic or additive effect of the three additives was not observed.  相似文献   

红松幼龄材与成熟材力学性质的差异   总被引：3，自引：0，他引：3  

刘迎涛  刘一星  李坚 《木材工业》2005,19(2):32-34

本文研究了人工林和天然林红松幼龄材与成熟材力学性质的差异.结果显示,成熟材的所有力学性质均高于幼龄材.幼龄材与成熟材的抗弯弹性模量差异在人工林红松中达0.01水平显著,天然林红松也达到0.01水平显著;人工林红松抗弯强度和弦向横纹抗压强度差异达0.05水平显著.抗弯强度、顺纹抗压强度、横切面硬度和弦向横纹抗压强度4项指标的差异达0.05水平显著.  相似文献   

中国主要人工林树种幼龄材与成熟材及人工林与天然林木材性质比较研究   总被引：19，自引：2，他引：19  

鲍甫成  江泽慧  姜笑梅  陆熙娴  骆秀琴 《林业科学》1998,34(2):63-76

本文对中国１０种人工林和４种天然林的幼龄材与成熟材及４个树种的人工林木材与天然林木材的构造特征、化学性质、物理性质、力学性质的３３项材性指标差异进行了比较研究。结果表明,在幼龄材与成熟材之间,在统计上表现出差异显著性的为幼龄材比成熟材生长轮宽,管胞列数多,管胞短,直径小,微纤丝角大,密度小,径向干缩小,差异干缩大,流体扩散性高,抗弯强度、抗弯弹性模量、顺纹抗压强度、径面顺纹抗剪强度、径面抗劈力和冲击韧性低等１５项,即４６％的测试项目差异显著;表明在木材加工和用作结构材时应将幼龄材和成熟材视作两个性质不同的总体来考虑,在培育结构材时应研究如何缩短幼年期或改善幼年期材性。在人工林与天然林木材之间,采取人工林幼龄材性质与天然林幼龄材性质相比,人工林成熟材性质与天然林成熟材性质相比,结果表明,多数性质在统计上差异不显著,只有人工林木材比天然林木材胞壁率小、顺纹抗压强度低、差异干缩大、流体扩散性高等４项,即只有１２％的很少数测试项目差异显著;表明有可能通过人工培育的方法培育出与天然林木材性质相近的木材。  相似文献   

樟子松种源试验幼林期生长性状变异初探   总被引：2，自引：0，他引：2  

刘永红  王思恭 《陕西林业科技》1997,(3):12-14

对樟子松在五台，宁东，太白三个地点的苗期和幼林期的生长性状进行了分析。结果表明：不同种源间高生长存在极显著的差异，种源内个体变异也十分明显。高生长是随纬度增高而递减的渐变模式，而发芽率和发芽速度则无明显的地理变异。初步选择出生长良好，稳定性强的１３、１６、２０、１５、２号种源。  相似文献   

Isolation of a highly pathogenic Vibrio pelagius strain associated with mass mortalities of turbot,Scophthalmus maximus (L.), larvae   总被引：2，自引：0，他引：2  

Villamil L  Figueras A  Toranzo AE  Planas M  Novoa B 《Journal of fish diseases》2003,26(5):293-303

A bacterial strain, characterized as Vibrio pelagius (Hq 222), was isolated from a turbot, Scophthalmus maximus (L.), larvae mass mortality in a commercial fish farm in Spain. Turbot larvae, post-larvae (0.2 g) and juveniles (5 and 15 g) were experimentally infected. The bacterium appeared to be very virulent for larvae and post-larvae, LD50 being < 5 bacteria mL(-1) for larvae 1 week post-infection and 3.9 x 10(5) bacteria mL(-1) in post-larvae at day 12 post-infection. The bacterial strain was recovered in pure culture from the internal organs of infected fish. Histological lesions in post-larvae exhibited swelling and necrosis of gill secondary lamellae, sloughing of intestinal mucosa and necrosis of haematopoietic tissue in the kidney. Vibrio pelagius (Hq 222) was able to grow in sterile sea water when incubated at room temperature or at 15 degrees C. Vibrio pelagius (Hq 222) was more adherent to the turbot cell lines TV-1 and TF than Escherichia coli. In both cell lines, the number of adhered bacteria increased with incubation time.  相似文献