南京近郊农田大气颗粒物及金属干沉降输入特征

大气颗粒物中重金属干沉降输入是农业区域重金属的重要来源之一,但当前对农业区大气重金属沉降的观测研究较少.通过对南京近郊典型稻麦轮作区定点连续1 a采样,分析了不同粒径大气颗粒物和其中10种金属元素的浓度,并利用大叶模型估算其干沉降通量.结果表明,颗粒物浓度和干沉降通量均呈现冬春高、夏秋低的变化趋势;冬春季颗粒物污染为粗粒子(2.1～9.0μm)和细粒子(<2.1μm)的双重作用,而夏秋季则主要为细粒子的作用;金属元素浓度在巨粒子(>9.0μm)中占比最低,在粗粒子和细粒子中相当,而Pb、 Mn、 As和Cd在细粒子中占比较高;10种金属元素的年均干沉降通量[mg·(m²·a)^-1]大小为：Ca(2 096.4)>Al(1 710.4)>Zn(855.0)>Fe(256.1)>Pb(40.35)>Cu(31.93)>V(26.21)>Mn(9.10)>As(2.48)>Cd(0.28).研究结果为更加全面地认识人类活动对农产品质量安全和土壤生态环境的影响提供参考依据.     

The Upper and Lower Ecological Limits of Specific Metabolic Power of Different Organisms

It has been demonstrated that bioenergetic properties of plants (independence of productivity from size, proportionality between radial growth of woody plants and plant mass, etc.) and animals are not related to the presumed universal linear relationship between metabolic power and body mass to the power of 3/4. This relationship is not true for plants and endothermic animals. The observed bioenergetic characteristics of these organisms are explained by simple biological and physical laws, including the existence of the lower and upper limits of the specific metabolic power of living matter.     

The role of humic substances in chromium sorption onto natural organic matter (peat)

To elucidate mechanisms of Cr³⁺ sorption onto the unaltered solid natural organic matter, the comparative studies of this ion binding from a solution at pH 4.0 onto three selected particle size fractions: 2000–1000 μm, 630–200 μm and 63–20 μm of markedly different HS content and structure, separated by a wet sieving from an overall sample of peat (Brushwood Peat Humus) were carried out. Comparable patterns of COOH groups and CEC_t confirmed that for cation exchange capacity were responsible mainly cations connected with COO⁻ functional groups. It was though found that aliphatic acids in the solid state did not take part in Cr³⁺ binding, thus the finest studied fraction 63–20 μm of the highest contents of functional groups showed the lowest sorption capacity for Cr³⁺, while similar patterns of sorbed Cr³⁺, soluble HS content and base CEC₀ indicated that these parameters were directly interrelated. The base ion exchange processes determined by CEC₀ (with Ca²⁺ as a predominant exchangeable cation) appeared to be not the major mechanisms responsible for Cr³⁺ sorption. For this metal, strong binding to insoluble large molecular weight organic pool two- to threefold prevailed over the ion exchange processes. Very low acid desorption indicated generally low mobility of Cr³⁺-organic compounds.     

深圳大气有机硝酸酯粒径分布特征和来源研究

于2021年3月30日至2021年4月17日利用超高分辨率气溶胶飞行时间质谱(Long-ToF-AMS),对深圳城市大气中的颗粒态有机硝酸酯(pON)开展高精度分析.基于两种估算pON的方法,计算得出pON对有机气溶胶(OA)的贡献占比为5.08％～11.00％.pON的日变化特征显示,其高值主要出现在夜间时段(19:...     

惰性粉体对蔗糖粉尘最小点火能的影响研究

为了预防蔗糖粉尘爆炸,利用1.2 L哈特曼管研究了NH₄H₂PO₄与Al(OH₄对蔗糖粉尘爆炸的抑制作用。在蔗糖粉尘质量分数一定的条件下,通过改变 NH₄H₂PO₄与Al(OH)₄的粒径和质量分数,测定其对蔗糖粉尘爆炸的抑制效果。结果表明:随着NH₄H₂PO₄和Al(OH)₄质量分数的增加,粒径的减小,蔗糖粉尘的最小点火能均逐渐增大,当惰性粉体增加到一定质量时,蔗糖粉尘被完全惰化,在蔗糖粉尘中分别加入粒径为48~74,38~47,25~37 μm的NH₄H₂PO₄和Al(OH)₄,3种粒径的NH₄H₂PO₄使蔗糖粉尘完全惰化的质量分数分别为40%,35%,30%,3种粒径的Al(OH)₃使蔗糖粉尘惰化的质量分数均为60%。因此(NH₄)H₂PO₄抑制蔗糖粉尘爆炸的效果比Al(OH)₃更显著。     

南岳森林土壤的研究-Ⅲ.土壤颗粒组成

本文介绍了南岳森林土壤颗粒组成状况及其与环境间的关系,以及土壤的颗粒组成状况对其理化性质的影响。研究表明,南岳土壤质地主要为粉壤土、面砂土和壤粘土等。土壤质地的差异主要受植被类型、植物生长状况、放牧严重与否的影响,其次是受坡度和气候条件的影响。土壤颗粒组成状况显著地影响土壤的速效磷、速效钾、浸水容重、吸湿率、烧失率、pH值等,对土壤紧实度、有机质、碱解氮也有一定的影响。     

Neighbours, strangers and male-male aggression as a determinant of lek size

Interactions between males on leks may play an influential role in lek formation and the regulation of lek size. In this paper I present the results of a playback experiment that simulated de novo settlement at sites adjacent to currently existing display territories of the ochre-bellied flycatcher, Mionectes oleagineus. In the study population, males displayed both solitarily and at small leks. A large proportion of males held no display territory at all. A stranger's song was played to both solitary and lekking males from 10 m outside their territorial boundaries. In separate playbacks, lekking males were also played neighbour's song. Both lekking and solitary territorial males reacted to the playback by decreasing their song rate, approaching the playback speaker and, on occasion, attacking the model. Solitarily displaying males responded more aggressively to playback of stranger's song than did lek males. Lek males were able to distinguish between their neighbour's and a stranger's song and did so irrespective of whether it was played from the neighbour's territory or from outside the lek. In addition to distinguishing between neighbours and strangers, lek males modified their responses to these different playbacks depending on where the playback originated. These results suggest that male-male interactions can be influential in structuring leks. In M. oleagineus, interactions between males are aggressive and act to limit rather than augment lek size. Received: 6 March 1996 / Accepted after revision: 9 December 1996     

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     

Estimating the complexity of bird song by using capture-recapture approaches from community ecology

Repertoire size, the number of unique song or syllable types in the repertoire, is a widely used measure of song complexity in birds, but it is difficult to calculate this exactly in species with large repertoires. A new method of repertoire size estimation applies species richness estimation procedures from community ecology, but such capture-recapture approaches have not been much tested. Here, we establish standardized sampling schemes and estimation procedures using capture-recapture models for syllable repertoires from 18 bird species, and suggest how these may be used to tackle problems of repertoire estimation. Different models, with different assumptions regarding the heterogeneity of the use of syllable types, performed best for different species with different song organizations. For most species, models assuming heterogeneous probability of occurrence of syllables (so-called detection probability) were selected due to the presence of both rare and frequent syllables. Capture-recapture estimates of syllable repertoire size from our small sample did not differ significantly from previous estimates using larger samples of count data. However, the enumeration of syllables in 15 songs yielded significantly lower estimates than previous reports. Hence, heterogeneity in detection probability of syllables should be addressed when estimating repertoire size. This is neglected using simple enumeration procedures, but is taken into account when repertoire size is estimated by appropriate capture-recapture models adjusted for species-specific song organization characteristics. We suggest that such approaches, in combination with standardized sampling, should be applied in species with potentially large repertoire size. On the other hand, in species with small repertoire size and homogenous syllable usage, enumerations may be satisfactory. Although researchers often use repertoire size as a measure of song complexity, listeners to songs are unlikely to count entire repertoires and they may rely on other cues, such as syllable detection probability.Communicated by A. Cockburn