Food abundance and parental care in yellow warblers (Dendroica petechia)

Emlen and Oring (1977) suggested that monogamy in birds is maintained because of the need for strict biparental care. A corollary of their suggestion is that paternal care should decrease under conditions of high food abundance. An alternative is that paternal care would increase if males take advantage of the higher food abundance by trying to reduce the length of the nestling feeding period. We tested these two ideas using yellow warblers (Dendroica petechia) by providing some pairs with supplemental food, thereby reducing the importance of biparental care. However, the extra food did not decrease paternal effort, nor did it increase it (Fig. 2). Early in the nestling period experimental females brooded more but visited their nestlings less than did control females, but later, when brooding times decreased, experimental females fed their nestlings more than did control females (Fig. 3). There were no significant differences in nestling survival (Fig. 5), but nestlings in the control treatment were larger and heavier up to 6 days old (Fig. 6). The main effect of supplemental food was on maternal, not paternal behaviour. Models of biparental care assume interdependence between the parental effort of both parents. In this species, however, males and females provide for their brood independently from each other.     

Exploring Population Dynamics Patterns in a Rare Fish, Zingel asper, through Capture-Mark-Recapture Methods

Abstract:  We performed a capture-mark-recapture study on one of the last populations of Zingel asper , an endemic percid species of the Rhône River basin in France. The distribution of Z. asper has decreased dramatically during the last century. We sampled three sites in suitable habitats in the Beaume River. No impact of individual tagging on survival was found. The demography of the population was analyzed using capture-recapture methods that allow the estimation of survival, recruitment, and demographic growth rates. Annual survival rates were low (0.35–0.50). The level of transience was high (5% to 25%), suggesting that a significant number of individuals were highly mobile or shifted to suboptimal habitats. Seniority rates suggested random highly variable recruitment between years. The three sites had similar variation patterns in all demographic parameters, indicating broad spatial covariation in population dynamics. We found some local differences in demographic parameters, which could be linked to local habitat quality. Individual tagging allowed for the estimation of demographic parameters that improved our understanding of Z. asper population dynamics and revealed mechanisms that may affect population persistence, such as stochastic recruitment, low survival, and frequent dispersal. The fragmentation of habitat through river damming inhibits dispersal and represents a threat to the persistence of Z. asper in the Rhône basin. Our results offer evidence of the importance of dispersal in nonmigratory fishes and confirm the usefulness of individual tagging methods in rare fish demography.     

光生物反应器培养紫球藻及藻粉降血脂的研究

研究了搅拌式光生物反应器中搅拌速度、通气量对紫球藻生长、胞外多糖和藻细胞超微结构的影响．实验结果表明：在特定光照(1000μmolm^-2s^-1)和培养温度(25℃)条件下，当搅拌转速为200r／min、通气量为0．71vvm时，藻生长速度和胞外多糖含量最高；增加通气量有利于藻细胞胞外多糖及生物量的提高．对藻细胞超微结构的观察发现，与摇床培养相比，搅拌式光生物反应器使藻细胞淀粉颗粒明显增多，粘质鞘层变薄，光合片层增多．动物实验表明，紫球藻能明显降低摄食高脂饲料SD大鼠血脂TC、TG、LDL-C水平，并提高HDL-C含量．实验结果预示，紫球藻对预防动脉粥样硬化和冠心病的发生有一定的意义．图2表3参26     

Renewable resources in an endogenously growing economy: balanced growth and transitional dynamics

We introduce a renewable resource sector into an endogenous growth model of a small economy, deriving the transitional dynamic equilibrium. The model generates a long-run equilibrium in which a resource sector of limited size can coexist with constant ongoing growth elsewhere. The key feature of the model is the allocation of labor between harvesting the resource and its use in the final output sector. This naturally generates the empirically observed negative relationship between resource abundance and growth. We examine both the dynamic and long-run responses of the economy to various shocks pertaining to technological production conditions and resource sector parameters.     

阿特拉津降解菌的生长规律及降解特征的实验

应用了从农药厂阿特拉津生产车间污泥中分离出的菌种AT菌，进行了菌种生长曲线的测定，求得AT菌的对数期代时为3．87d，生长速率为0．258d^-1；不同基质浓度的降解实验表明，在农药污染质阿特拉津的低浓度体系中，AT菌降解阿特拉津的反应符合一级动力学模式，属于米氏方程曲线的第一阶段的情形，并拟合出关系式V＝0．064S。     

海洋纤毛虫实验生态学研究I：不同浓度葡萄糖对种群增长的影响

为揭示不同碳氮比对纤毛虫种群增长的影响以及纤毛虫对碳源和能量来源的选择性 ,利用实验生态学方法 ,对海水养殖水体中 3种常见的纤毛虫原生动物 :扇形游仆虫 (Euplotesvannus)、海洋尾丝虫 (Uronemamarinum)和巨大拟阿脑虫 (Paranophrysmagna)在牛肉浸膏及梯度浓度葡萄糖培养基中的种群增长过程进行了初步的探讨 .数据分析表明 ,在牛肉浸膏培养基中加入不同浓度的葡萄糖对于纤毛虫种群增长影响显著 ,其中在 0 .0 5 gL-1葡萄糖浓度的培养基中 3种纤毛虫种群增长最佳 (P <0 .0 5 ) ,而在 0 .4 gL-1浓度时纤毛虫的生长繁殖均受到高度抑制 (P <0 .0 5 ) .这一结果显示 ,不同C N比对纤毛虫的种群增长有着直接的影响 .图 3表 3参 10     

三倍体毛白杨引种育苗试验研究

采用2000年引进的三倍数体毛白杨73、80、96、330、331及本地繁育的303、304、305等品种在不同土壤上进行育苗、造林试验.育苗试验表明:土壤质地及肥力对育苗成活率无明显影响,成活率引最高69.4%,苗木高、径生长8月达到高峰,最高达0.93 m (331号)和0.51 cm (96号);造林试验表明:造林成活率与土壤湿度、地下水位密切相关,生长量与品种及土质密切相关,造林密度为89-110株/667㎡,截干高度1.8-2.3 m为宜,综合表现以96号最佳.     

New particle formation observed from a rain shadow region of the Western Ghats,India

Abstract

This study reports on new particle formation (NPF) and characteristic features observed from a rural site falling in the rainshadow of the Western Ghats in peninsular India. A total of 35 NPF events observed during August 2018 - January 2019 are classified and analyzed here. The apparent formation rates ranged from 0.2 to 10.0?cm^–3 s^–1, while the growth rates of nucleation mode particles ranged from 1.2 to 13.8?nm h^–1. The frequency of occurrence was least during August (core monsoon) and highest during post-monsoon. The local winds were calm and southeasterly to easterly (from the urban centre) supplying the essential precursor gases during October and November, leading to a frequent occurrence of nucleation events. Observations suggest that an increased condensation sink could limit the NPF while promoting Aitken mode growth. The newly formed particles accounted for about 10–80% of the total aerosol concentration. These newly formed particles were able to act as cloud condensation nuclei after growing to approximately 50?nm with an average activation fraction of 0.4.     

2种常规水稻Cd、Zn吸收与器官分配的生育期变化：品种、土壤和Cd处理的影响

Cd在土壤-作物-膳食食物链中的迁移是人类对环境Cd暴露及其健康风险的主要途径,而水稻是子粒Cd积累最强的大宗作物之一.采用全生育期淹水盆栽试验研究了2种常规水稻(高Cd吸收品种“苏香粳1号”和低Cd吸收品种“99-22”)在添加Cd(2mg·kg-1)和不添加Cd处理下对2种土壤(红沙泥田,乌栅土)中Cd、Zn的吸收及其生育期变化.结果表明:1)常规水稻对Cd、Zn的吸收积累受土壤、品种和外源Cd的影响.Cd处理、土壤、品种间的正交互作用(高Cd吸收品种植于高Cd处理且Cd有效性高的红壤中)使常规稻植株Cd/Zn比成数十倍提高,从而使子粒Cd/Zn比产生强烈升高;2)水稻对Cd、Zn的吸收强度因不同生育期而异,Cd吸收的主要时期是分蘖期和成熟期,而Zn吸收的主要时期则是分蘖期、抽穗期和灌浆期.在整个生育期中,水稻Cd吸收伴随着对Zn的排斥现象,这在高Cd吸收下尤为强烈;3)水稻各器官对Cd、Zn的吸收分配无论是同品种的生育期间抑或同生育期时的不同品种间均有显著差异.Cd积累量为根系>穗粒>茎叶,而Zn却表现为茎叶>根系、穗粒.观察到水稻吸收的Cd在生育后期向穗粒的强烈运移.相对于低Cd吸收品种来说,Cd向穗粒转运较强,而Zn的转运较弱是高Cd吸收品种子粒Cd积累强而Cd/Zn比高的植株因素.     

菰和菖蒲在污水中的生长特性及其净化效果比较

通过漂浮栽植菰(Zizania latifolia)和菖蒲(Acoruscalamus),研究了它们在低、中、高3种浓度污水中的生长特性及其对这3种浓度污水的净化效果.结果表明,菰和菖蒲均在中浓度污水中生长最好.菰在中浓度污水中的生物量显著高于低浓度和高浓度中;菖蒲在中浓度污水中的生物量略高于低浓度和高浓度中,但差异不显著.菰对中浓度污水中TN、NH3-N、TP和CODCr的去除率分别为97.4%、95.3%、98.5%和71.4%,对高浓度污水中TN、NH3-N、TP和CODCr的去除率分别为96.4%、97.7%、88.2%和76.1%,净化效果均显著高于低浓度中.菰可作为中、高浓度污水的净化植物.菖蒲净化中浓度污水的效果最好,对TN、NH3-N、TP和CODCr的去除率分别为97.5%、94.1%、98.5%和72.7%;对高浓度污水中的NH3-N和CODCr去除效果也较好,去除率分别为97.8%和86.7%,但对TN和TP的去除率分别为89.5%和70.9%,显著低于对低浓度和中浓度污水中TN和TP的去除率.图1表4参13