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21.
Marina Do Souto Daniel R. Brown Valeria Segura Rubn Negri Brenda Temperoni Georgina Cepeda Maria D. Vias Fabiana L. Capitanio Marina V. Diaz 《Fisheries Oceanography》2019,28(5):597-611
Dynamics of clupeiform fish populations such as anchovy are frequently impacted by environmental variations which can affect the success of the species recruitment. Herein, we have analyzed recent otolith growth rate, RNA/DNA nutritional condition index (sRD), and mortality rate of argentine anchovy larvae Engraulis anchoita from three different nursery areas in the Southwest Atlantic. We have evaluated the relationship between the environmental variables (abundance of copepod nauplii, temperature, chlorophyll‐a concentration, and abundance of E. anchoita larvae) and larval endogenous variables (size, weight, age, and otolith radius) to sRD and recent growth rate. Fast larval growth rates were observed toward the northern sector of the studied area, characterized by higher temperature. High values of sRD were associated with higher nauplii abundance in the proximity of coastal fronts. The larvae with the lowest growths and lowest minimum values of nutritional condition coincided with the area where there was less abundance of nauplii and higher larval mortality. Larval size and nauplii abundance were positive explanatory factors for both recent growth rate and sRD index. Temperature had a positive effect on recent growth rate and a negative effect on sRD index. This condition index was poorly explained in terms of model fit in comparison with the growth model. The results herein provided could be significant to better understand the recruitment of the species, as to determining favorable areas for the growth and survival of anchovy larvae. 相似文献
22.
Turgish A Banu Mohammed Shamsuddin Jayonta Bhattacharjee Mohammad F Islam Saiful I Khan Jalal U Ahmed 《Acta veterinaria Scandinavica》2012,54(1):30
Background
Application of assisted reproductive technologies in buffaloes is limited to some extent by farmers’ inability to detect oestrus because of its poor expression. The present study aimed at investigating reliability of a milk progesterone enzyme-linked immunosorbent assay (ELISA) to assess the ovarian cyclicity during post partum, oestrus and post-breeding periods in water buffaloes.Methods
Progesterone concentrations were measured by an ELISA in milk of 23 postpartum buffaloes in relation to oestrus, pregnancy, body condition score (BCS) and milk production. Two milk samples were taken at 10 days intervals, every month starting from day 30 and continued to day 150 post partum. BCS and milk production were recorded during sample collection. Milk samples from bred buffaloes were collected at Day 0 (day of breeding), Days 10–12 and Days 22–24. Defatted milk was preserved at −80°C until analysis. Pregnancy was confirmed by palpation per rectum on Days 70–90.Results
Seventeen buffaloes had 47 ovulatory cycles, one to four in each, 13 were detected in oestrus once (28 % oestrus detection rate). Progesterone concentration ≥1 ng/ml in one of the two 10-day-interval milk samples reflected ovulation and corpus luteum formation. The intervals between calving to first luteal activity and to first detected oestrus varied from 41 to 123 days (n = 17) and 83 to 135 (n = 13) days, respectively. Eight buffaloes were bred in the course of the study and seven were found pregnant. These buffaloes had a progesterone profile of low (<1 ng/ml), high (≥ 1 ng/ml) and high (≥ 1 ng/ml) on Day 0, Days 10–12 and Days 22–24, respectively. Buffaloes cycling later in the postpartum period had fewer missed oestruses (P < 0.05). Buffaloes with a superior BCS had a shorter calving to oestrus interval and produced more milk (P < 0.05).Conclusions
Milk progesterone ELISA is a reliable tool for monitoring ovarian cyclicity and good BCS may be an indicator of resuming cyclicity in water buffalo. 相似文献23.
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为使栽培出来的黄花蒿达到绿色药材的标准,对广西融安县潭头乡黄花蒿种植基地生态环境质量进行评价。参照国家环保局《环境检测分析方法》布点采样,对黄花蒿规范化种植基地的大气环境、土壤环境和水源质量进行检测。空气质量监测采用国家规定环境空气质量标准(GB3095-1966)进行;土壤环境按国家标准GB15618-1995(土壤环境质量标准)和YB-T-1-2003(药用植物绿色出口生产基地行业标准),增加五氯硝基苯、艾氏剂项目;灌溉水质采用GB5084-92《农田灌溉水质标准》要求进行检测;对原有的野生黄花蒿植株进行重金属检测。广西融安县潭头乡黄花蒿种植基地大气质量达到GB3095-1996一级标准,水源质量达GB5084-92标准,土壤环境达GB15618-1995二级标准,野生黄花蒿植株重金属含量符合《药用植物及制剂外经贸绿色行业标准》(WM2/T-2003)要求。广西融安县潭头乡新黄花蒿种植基地环境质量良好,各生态条件适合黄花蒿生长。符合药用植物绿色出口生产基地行业标准(YB-T-1-2003)的要求。 相似文献
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利用振动特性诊断流程泵的运行工况 总被引:1,自引:0,他引:1
用所建立的用于描述振动强度的范数说明了泵在偏离原设计工况运行时会导致泵轴向力和径向力的增大。将流程泵叶轮叶片和压水室的隔舌看作旋涡发生体,在不同运行工况下在叶片后缘以及隔舌两侧串联发生的卡门涡街的发射频率是不同的。采用加速度传感器采集的振动信号正反应了这种工况变动。通过对振动信号进行基于EMD的能量算子解调以及频谱分析,发现得到的最大幅值处的频率就是叶轮叶片的通过频率。试验表明,得到的次大幅值处的频率就是卡门涡街的发射频率,可根据该频率处幅值的相对大小来判断泵是否在合理的工况内运行。 相似文献
28.
清代士子一旦中举,即失去了原有的官学学生资格,但举人仍有读书应试之需。于是,至清代晚期,各地出现由官府创建的专课举人的书院,专门招收举人,开展应试教育。与此不同,有的书院则兼课举人,并由官府设立孝廉课,专课举人。从总体上而言,专课举人和兼课举人的书院以培养生徒参加会试、殿试为目的,不仅在考课时模拟会试、殿试,而且在经费的投入、对考课的重视程度上,都超过了同一地区的其他书院,使肄业于书院的举人在竞争激烈的会试、殿试中脱颖而出的几率明显提高。 相似文献
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