不同碳源及光照对小球藻生长和产油脂的影响

考察了3种碳源(葡萄糖、NaHCO3和乙酸钠)在不同初始质量浓度和光照条件下对小球藻(Chlorella vulgaris)生长和产油脂的影响。采用OD680和生物量来评价小球藻的生长情况;以溶剂浸提法提取生物油脂,并以油脂质量分数和油脂产量来描述产油脂特性。结果表明,经过9 d的培养,3种碳源中葡萄糖是最佳有机碳源。由其培养的小球藻生长速率最快,由NaHCO3培养的小球藻的生长效果不如葡萄糖,而乙酸钠不利于小球藻的生长。随着光照的增强,小球藻光合效率提高,生物量逐渐提高,5 000 lx最利于小球藻的生长,而1 600 lx最利于小球藻油脂的积累。研究表明,光照5 000 lx下,初始质量浓度为15 g/L的葡萄糖作为碳源是小球藻适宜的生长和产油条件,获得了3.17 g/L的最大生物量和1.025 g/L的最大油脂产量。     

飞行员人因可靠性定量预测

为有效预测飞行员的人因可靠性,以保障飞行安全,基于认知可靠性与失误分析法(CREAM)的扩展法,建立飞行员人因可靠性定量预测模型。依据飞行员的任务特点,调整认知行为及认知功能。通过优化共同绩效条件(CPC)因子水平等级,并增加新的因子,改进CPC因子依赖规则,用于修正因子的初始评估结果,解决扩展法未考虑因子间关系的问题,从而完成模型的建立。利用回看分析法验证模型的有效性,采用所建立的模型和扩展法分别对已发生的飞行案例进行预测,并与实际发生结果对比分析。结果表明,与扩展法相比,采用飞行员定量预测模型得到的预测结果与案例发生结果所反映的控制模式更为匹配。     

Theoretical pressure prediction of confined hydrogen explosion considering flame instabilities

In order to ensure the safe utilization of hydrogen energy, the explosion pressure behavior is extremely important to design chemical equipment and evaluate explosion accident consequence. This paper is aimed at establishing a theoretical method of predicting explosion pressure behavior in the confined chamber by considering flame instabilities. The tendency of flame wrinkling factor in the pressure-buildup stage is firstly evaluated using large eddy simulation and the compensation theory. The limiting value of flame wrinkling factor during entire explosion process is calculated using the fractal theory. Finally, the dynamic model of flame wrinkling factor is implemented into the smooth flame model. The results demonstrated that the flame wrinkling factor in the pressure-buildup stage almost increases linearly with time. The limiting value of flame wrinkling factor is 2.4649. The explosion pressure will be underestimated using the smooth flame model, and the calculated explosion pressure in the isothermal condition is smaller than that in the adiabatic condition. When the fully turbulent flame is considered, the explosion pressure will be overpredicted significantly. By changing the confined chamber size, the explosion pressure could be reproduced relatively satisfactorily when the flame wrinkling factor is assumed to increase exponentially. The explosion pressure prediction must consider the effect of adiabatic compression and flame instabilities on burning rate.     

信宜县田七场的土壤环境

本文在野外调查的基础上，论述了广东省主要田七产区信宜县田七场的生物气候条件、地理位置、土壤肥力以及田七对Ｎ、Ｐ、Ｋ的吸收状况．改善田七场的环境条件，合理施肥，培育健壮的植株以及减少农药使用量等，是提高田七产量的有效措施．     

生淀粉糖化酶产生菌Aspergillus niger(6#)的分离筛选及其产酶条件

从大曲中分离到了1株降解生淀粉能力较强的黑曲霉Aspergillusniger(6#).固体发酵酶活可达2461U/g,RDA值为21.47%;液体发酵酶活可达353U/mL,RDA值为20.30%.以6#菌为实验材料,进一步考察了氮源、碳源及pH对生淀粉糖化酶形成的影响.实验结果表明,无机氮源NaNO3较有机氮源蛋白胨更有利于生淀粉糖化酶的形成;pH是影响生淀粉糖化酶形成的重要因素,低pH会阻遏生淀粉糖化酶的形成;玉米粉和麦芽糖较其它碳源更有利于生淀粉糖化酶的形成.图4表2参12     

产聚乙烯醇降解酶的培养条件

放线菌StreptomycesvenezuelaeGY1产生的聚乙烯醇(PVA)降解酶是一种诱导酶.以4种不同类型的PVA为唯一碳源时,该菌株单位质量细胞产酶能力比以糖类物质为唯一碳源时提高10倍以上.聚合度和醇解度最高的PVA1799是该菌株产生PVA降解酶的适宜底物,其浓度为1gL-1时,PVA降解酶的产量为120u/g(细胞).培养基中PVA1799浓度由1gL-1上升到5gL-1时,该菌株单位质量细胞产酶能力下降73%,表明PVA1799浓度过高会抑制产酶.GY1菌株产酶的最适温度和pH分别为30℃和7.0.在GY1菌株生长过程中控制以下条件有利于产生PVA降解酶:(1)保持培养体系中较高的溶氧水平;(2)在氮源中补充NO-3;(3)在一定浓度范围内添加MgSO4·7H2O、CaCl2、MnSO4、BaCl2、ZnSO4、FeSO4·7H2O和CuSO4等金属盐.Pseudomonassp.产生的PVA降解酶能够作用伯醇或仲醇类化合物,以这些伯醇或仲醇类化合物代替培养基中的PVA,不能诱导GY1菌株产生PVA降解酶;而在培养基中有PVA存在时,再添加0.5gL-1的3戊醇和环己醇能够明显促进PVA降解酶的产生(单位质量细胞产酶能力分别提高了21%和32%).图8表1参10     

Factors influencing length of maternal care in brown bears (<Emphasis Type="Italic">Ursus arctos</Emphasis>) and its effect on offspring

Length of maternal care, i.e. the interval between successfully raised litters, is the most important factor explaining the variation in reproductive rate among brown-bear (Ursus arctos) populations. In this paper, we examine the variation in length of maternal care in radio-marked brown bears and its effect on their offspring in northern Sweden. Young stayed with their mothers for 1.4–1.5 or 2.4–2.5 (in one case 3.5) years and were weaned with body masses varying from 17 to 69 kg. The probability of yearling litters staying with their mother for a 2nd year increased with decreasing yearling body mass, and was higher for litters with two offspring than for litters with one or three to four offspring. Staying with their mothers for a 2nd year had a positive effect on mass gain in yearlings and this effect was more pronounced in litters with two than three to four offspring. Body mass of 2-year-olds was not related to age of weaning, suggesting that keeping offspring for an additional year mainly compensated for low yearling body mass. If large offspring body mass positively affects later offspring survival and reproduction, mothers may be able to optimize the length of maternal care according to the litter size and the size of their yearlings.Communicated by F. Trillmich     

Reproductive effort of colonial and solitary breeding tree sparrows Passer montanus L.

A total of 250 nestboxes were arranged in five plots in a suburban area of Budapest, Hungary (19°04E, 47°41N). In each plot, 25 were placed at 50 m intervals to simulate solitary breeding and 25 3–5 m apart to simulate colonial breeding. Length of nest building period, feeding frequency, nestling mortality, nestlings' diet, productivity and parental condition were compared for colonial and solitary breeding tree sparrows Passer montanus. Parents with long nest-building periods, including the majority of first-year females, produced fewer young than parents which built over short periods. Parents fed nestlings morefrequently and nestlings had lower mortality in second than first broods; whether or not a third brood was reared was determined by the costs invested in first and second broods. Females that laid a third clutch had reared fewer young in first and second broods and were heavier than females that reared many young in two broods. Colonial birds had higher feeding frequencies, more similar diets and suffered lower nestling mortality than solitary parents for first broods, but they fed less frequently, diets were less similar, and nestling mortality was higher in second and third broods. It is suggested that colonial breeders benefited from the social stimulation of simultaneous feeding in first broods, but the advantage of synchronicity in feeding declined in second broods and the sparser breeding spacing of solitary parents was more advantageous for feeding in second and third broods. Birds that changed nest spacing between broods had fed nestlings less frequently and had higher nestling mortality before changing than birds which retained their spacing. Parents which changed from colonies to solitary nests fed more frequently with lower nestling mortality in the next brood than parents which retained colonial nests for their second (and third) brood. Solitary parents did not show such a relationship. The rearing of three broods caused higher weight loss in colonial than solitary parents.Correspondence to: L. Sasvári     

农药杀螟硫磷酶促降解的研究

从长期受农药杀螟硫磷污染的土壤中分离到一株高效降解菌株,研究了其最适产酶条件:培养温度为30℃,培养液起始pH为7.0,培养时间为30 h.从该降解菌中提取的粗酶液在pH 7.5和30℃时显示最大的降解活性,其米氏常数Km为2.92×10-4mol/L,最大降解速率为2 422.79 nmolm in-1mg-1.图7参15     

关于肥满度指数的讨论

肥满度指数,也称身体状况指数,广泛应用于各个动物类群和生态学、生理、生化、遗传学以及养殖业.至今已有多种肥满度指数提出,从计算公式结构上,肥满度指数可以划分为比值法和残差法两大类.通过对各种肥满度指数的分析,Le Cren相对状态指数Kn、log10(体重)与log10(身体大小指数)线性回归的(标准化)残差这两种肥满度指数系统误差相对较小.实际应用中最好根据所考察的问题分别计算不同年龄段、性别的个体的肥满度指数来分析肥满度指数.由于定义的模糊性及其前提假设缺乏广泛验证,因此,肥满度指数在实际应用中需要谨慎考察其前提假设是否满足.参33