英语专业基础阶段内容依托教学应用问题的实证研究

选取长春科技学院外语学院2013级英语专业学生为研究对象,运用了定性研究方法结合非正式观察和半结构化访谈两种研究手段,对英日和英韩两个双语专业的学生,就内容依托教学在英语专业基础阶段教学的实践效果进行实证研究,并指出了目前教学存在的问题：教学内容中的生词问题;语言技能与内容知识的教学比例问题;内容依托课程的教学方法问题;内容依托课程的教学评估问题,希望可以为探索内容依托教学法在英语基础阶段内容的研究提供有益的启示。     

Major histocompatibility complex and mate choice in the polygynous primate: the Sichuan snub‐nosed monkey (Rhinopithecus roxellana)

The highly polymorphic genes within the major histocompatibility complex (MHC) not only play a major role in immunity resistance, but also seem to provide hints for mate choice in some animal populations. In the present study we investigated MHC‐related mate choice in a small natural population (group size 40–55 individuals) of a polygynous primate, the Sichuan snub‐nosed monkey (Rhinopithecus roxellana). We found that there was no evidence either for MHC‐disassortative mating, or for females to mate with males based on MHC heterozygosity or specific alleles. Nevertheless, of the 11 alleles identified, we found that the frequencies of 2 alleles, Rhro‐DRB2 (P < 0.01) and Rhro‐DRB5 (P < 0.05) were higher in offspring than in their parents. These findings suggest that MHC‐DRB in this population of R. roxellana is unlikely to be associated with mating preferences. Limited female opportunities for mate choice are likely due, in part, to the harem breeding structure present in R. roxellana, and the relatively small number of resident adult males in our study band (N = 4–6). In addition, we suggest that differences in the frequency of particular alleles across generations may be linked to parasite resistance in a fluctuating environment; however, confirmation of this finding requires further study.     

Seasonal changes in sperm production and quality in the red porgy Pagrus pagrus (L.)

Cultured red porgy Pagrus pagrus (L.) males (n=6) were sampled every 2 weeks for milt, in order to monitor changes in sperm quality parameters during a whole spawning period. On 11 January 2001, 60% of the fish were spermiating, increasing to 100% in mid‐February and dropping to 30% by mid‐April. Sperm density showed a slight increasing trend, with mean values ranging between 8.6 and 23.7×10⁹ spermatozoa mL^?1. Sperm motility percentage exhibited a significant improvement during the spawning season (analysis of variance (anova ) P=0.0001). The duration of forward motility for the major part of the monitoring period ranged between 2 and 4 min. Red porgy spermatozoa maintained their viability for many days after whole storage of milt at 4°C. During the monitoring period there were significant changes in the mean duration of sperm survival after cold storage, ranging from 5 to 12 days. The total volume of expressible milt was maximal on 28 March, increasing from a mean value of 1.7 mL to 5.3 mL kg^?1. Milt production of captive‐reared red porgy does not appear to be limiting, when compared with the volume of expressible milt produced by other cultured marine fishes.     

Digestive enzyme activity of the red porgy (Pagrus pagrus, L.) during larval development under culture conditions

The ontogenic development of the main digestive enzymes (proteases, amylase and lipase) in the red porgy, Pagrus pagrus, larvae was assayed during the larval development. The green water technique was carried out for larval rearing and whole‐body homogenates were used for enzymatic assays in triplicate. Significant alterations in specific activities of all digestive enzymes measured during the period of this study were mostly related to metamorphosis and weaning. Trypsin‐ and chymotrypsin‐specific activities were first detected on day 3, together with opening of the mouth, and slightly increased until 25 days after hatching (DAH). After this period, the specific activities of these enzymes slightly decreased. Pepsin was first detected on day 28, concurrent with stomach formation, and a sharp increase was observed until 30 DAH. A slight decrease was measured from this date until the end of the experiment. Both amylase and lipase were measured for the first time on days 2 and 4 respectively, and the specific activities of these enzymes showed similar patterns during the first week of the study. Then, slight variations were observed until 30 DAH and while lipase‐specific activity declined, an increase in the specific activity of amylase was found until the end of the experiment. It is concluded that the variations observed in the specific activity of digestive enzymes were related to either metamorphosis, such as the formation of the stomach (28 DAH), or to changes in food composition. The profile of the developmental pattern of the main digestive enzymes detected in P. pagrus is similar to that described for other Sparid species.     

Does water temperature determine year class strength in New Zealand snapper (Pagrus auratus,Sparidae)?

The abundance of 1+ snapper (Pagrus auratus) was estimated by trawl surveys and was found to vary 17-fold over 7 years. There was a strong positive correlation between year class strength and autumn (April-June) sea surface temperature during the 0+ year, with the latter explaining 94% of the variability in year class strength. The underlying mechanism is unknown, but three hypotheses relating snapper growth and survival to temperature are discussed. The strengths of the 1991 and 1992 year classes are predicted to be below average and extremely weak, respectively.     

Studies on the green liver in cultured red sea bream fed low level and non-fish meal diets: Relationship between hepatic taurine and biliverdin levels

SUMMARY: The aim of this study was to investigate the cause of green liver in red sea bream fed substitute protein diets. Red sea bream Pagrus major was given either of the following diets for 28 weeks: (1) control diet (50% fish meal), (2) low level fish meal diet (15% fish meal), and (3) non-fish meal diet (0% fish meal). The green liver was observed in all groups tested, but the incidence was much higher in the experimental diet groups. The feeding of substitute protein diets reduced plasma triglyceride and cholesterol levels. However, there was no significant difference in plasma hepatic enzyme activities and plasma bile salts concentration among the treatments. Fish fed the substitute protein diets showed low hepatic taurine levels with an appearance of a biliverdin in the liver. Moreover, the proportion of ditaurobilirubin to total biliary bile pigments was significantly lower in fish fed the substitute protein diets. These data indicate that feeding of substitute protein diets did not induce any cholestatic hepatobiliary obstructions and that the low hepatic taurine level was one of the probable factors responsible for the occurrence of green liver in red sea bream fed substitute protein diets.     

真鲷幼鱼狂游症病毒病原学初步研究

应用电子显微镜观察真鲷幼鱼内脏组织超薄切片。发现真鲷幼鱼脾脏存在大量病毒颗粒。病毒颗粒直径约１２０ｎｍ，呈六角形，有一层蛋白质外壳。核心主要为核心酸。病毒颗粒主要位于细胞核内。感染的细胞肿胀，比正常细胞增大５－６倍。在肠组织超薄切片中也发现少量形态相同的病毒颗粒。     

真鲷消化道的组织学和形态学研究

采用扫描电镜和光镜技术对真鲷的消化道进行了组织学和形态学研究。具发达颌齿的口咽腔之后，真鲷消化道由分化明显的食道、胃、小肠和直肠构成。口咽腔粘膜表面为复层上皮，其中含有怀状细胞和味蕾，表层细胞具微褶（脊）；食道粘膜也衬着复层上皮，由表层具微褶（脊）的扁平细胞、中层的怀状细胞及底部的基底细胞组成，食道粘部分区域 衬着单层柱状上皮；胃Ｖ形，粘膜表层为单层柱状上皮，贲门部和盲囊部上皮下有一厚层胃腺组织；     

基于四大家鱼产卵需求的汉江中下游生态流量研究

针对汉江中下游梯级电站开发后水文节律变化造成四大家鱼栖息地生境质量降低的问题,分别通过几种常用水文学法和栖息地模型计算了汉江中下游河道最小生态流量和四大家鱼产卵适宜生态流量,并在最小生态流量的基础上,结合四大家鱼产卵适宜生态流量以及生态水文特征在5-8月进行了脉冲设计,综合确定出了满足四大家鱼产卵需求的生态流量过程。结果表明,Lyon法和7Q10法最适宜汉江中下游最小生态流量的计算,流量为294~863 m3/s;通过栖息地模型计算,彭市和仙桃江段四大家鱼产卵适宜生态流量为1233~3950 m3/s;流量日涨幅在139.1~534.8 m3/s,持续5 d的涨水过程可为四大家鱼产卵提供良好的条件。该研究从考虑四大家鱼产卵需求的角度,为汉江中下游梯级电站的生态调度提供科学参考。