Heavy metals (Cu and Zn) in recent sediments of Llangorse Lake,Wales: non-ferrous smelting,Napoleon and the price of wheat — a palaeoecological study

Elevated concentrations of Cu and Zn have been found in the upper part of three sediment cores collected from Llangorse Lake, in south Wales. Palaeomagnetic evidence from one of the cores and ²¹⁰Pb analysis of another, suggests that the increase in sediment Cu and Zn concentrations began during the eighteenth century. A sharp increase in the concentrations of these metals in the sediment profile appears to have occurred during the latter part of the eighteenth century and these concentrations remained high until the mid to late nineteenth century.The absence of known ore deposits and industry around the lake suggests that the lake and catchment soils were increasingly contaminated by long-range aerial transport of emissions from the expanding activity of Cu and Zn smelters located some 80 km upwind in the Swansea area during the Industrial Revolution. Evidence from agricultural crop returns indicates a significant increase in the amount of land devoted to tillage in the catchment, particularly to cereal production, during the late eighteenth and the first half of the nineteenth century which included the Napoleonic Wars. This agricultural shift appears to coincide with increased concentrations of Cu and Zn in the lake sediments. It is suggested that newly ploughed soils, contaminated with metals for many years by long-range aerial transport from the Swansea area, eroded, and were carried into the lake by catchment run-off and added to the sediment burden of Cu and Zn. A subsequent decline of Cu and Zn emissions due to the collapse of the non-ferrous smelting industry and reduced soil erosion because of a 50% reduction of tillage due to an agricultural depression in the second half of the 19th century may explain the fall in Cu and Zn concentrations in the upper part of the sediment profile. The most recent sediments (20th century) show the increase in heavy metals characteristic of many lakes around the world.     

蒲公英抗肿瘤活性部位的GC-MS分析研究

目的：考察蒲公英提取物对MCF-7增殖作用的影响,研究蒲公英抗肿瘤活性部位的化学成分。方法：采用MTT法比较蒲公英水提物、醇提物和不同极性提取物对MCF-7增殖的影响;以气相色谱．质谱（GC-MS）联用技术对具有抑制MCF-7人乳腺癌细胞增殖的部位进行分离和鉴定。结果：蒲公英水提物和醇提物对MCF-7细胞均有抑制作用,体外最大抑制率分别达到92．95％、93．59％,蒲公英不同极性溶剂提取物中,氯仿部位抑制MCF-7的增殖,且抑制作用高于醇提和水提物,乙酸乙酯和石油醚部位促进MCF-7的增殖。从蒲公英氯仿提取物中鉴定出80种化合物,占其总量的98．07％。结论：蒲公英氯仿部位具有抗肿瘤活性,为蒲公英抗肿瘤活性成分的研究提供了依据,拓展了筛选中药活性成分的方法。     

长春蒲公英雄性不育株形态学观察与败育细胞学研究

在长春蒲公英(Taraxacum junpeianum Kitam.)株群中发现雄性不育现象,为研究其败育机理及特点,探寻其不育基因,采用形态观察法、石蜡切片技术和染色体压片法,对长春蒲公英野生型及其雄性不育株的花药发育过程和花粉母细胞减数分裂过程进行了观察。结果表明:(1)长春蒲公英雄性不育株花药中部发红、干瘪、无花粉散出。与野生型比较,雄性不育株雄蕊更短,子房更窄,种子形态更加狭长;(2)长春蒲公英雄性不育株败育时期为四分体到单核小孢子前期,败育方式为小孢子自身异常发育,绒毡层异常分解,互相粘连败育;(3)长春蒲公英雄性不育株花粉母细胞减数分裂二分体时期出现落后微核,随后产生极少四分体,并且四分体产生大量染色体桥,小孢子营养物质流失,彻底败育。因此,长春蒲公英雄性不育株败育彻底、稳定,并且有种的特点。小孢子自身异常发育和绒毡层异常分解是导致败育的主要原因。     

The variations of human sex ratio at birth during and after wars, and their potential explanations

Data on wartime sex ratios (proportions male at birth) are reviewed. Two sorts of variation are empirically well supported viz. (a) rises during and just after both World Wars and (b) a fall in Iran during the Iran-Iraq War. Potential explanations are offered here for these rises and fall. The fall seems plausibly explained by psychological stress causing pregnant women disproportionately to abort male fetuses. The rises may be explained by either or both of two different forms of hypothesis viz. (i) Kanazawa's “returning soldier” hypothesis and (ii) variation in coital rates. The coital rate hypothesis potentially accounts, in slightly different ways, for the rises both during, and just after, some wars. The argument that coital rate affects sex ratio just after wars seems to be supported by evidence that in some combatant countries, dizygotic (DZ) twinning rates (which also reportedly vary with coital rate) peaked after the World Wars. The suggestion that war is associated with rises in sex ratio at birth was first made more than two centuries ago. However, I have been unable to locate direct supporting sex ratio data relating to any conflict before World War One. So it would be useful if historical demographers were to search for such data relating to these earlier wars.     

Again,What the Philosophy of Biology is not

There are many things that philosophy of biology might be. But, given the existence of a professional philosophy of biology that is arguably a progressive research program and, as such, unrivaled, it makes sense to define philosophy of biology more narrowly than the totality of intersecting concerns biologists and philosophers (let alone other scholars) might have. The reasons for the success of the “new” philosophy of biology remain poorly understood. I reflect on what Dutch and Flemish, and, more generally, European philosophers of biology could do to improve the situation of their discipline locally, regionally, and internationally, paying particular attention to the lessons to be learned from the “Science Wars.” This paper grew out of my contribution to the symposium Philosophy of Biology in the Netherlands and Flanders organized by Thomas Reydon and Sabina Leonelli in Amsterdam in February 2004. It is a rather personal reaction to many of the opinions voiced in the quite heated atmosphere of the Symposium. My main concern is to convey an idea of what, according to me, is required to turn “our” philosophy of biology into a more successful enterprise than it currently is. This is motivated by a disconcerting discovery I made at the Symposium: Contrary to my expectations, a sensitivity for the sorts of things that make possible philosophy of biology of the best kind available today seems to be largely lacking in our part of the world. I wish to stress from the outset that although I will be quite polemical at times, this is always intended in the spirit of constructive dialogue.     

Oxalic Acid Production and Mycelial Biomass Yield of Sclerotinia minor for the Formulation Enhancement of a Granular Turf Bioherbicide

The fungus Sclerotinia minor is presently under development in this laboratory as a granular bioherbicide for broadleaf weed species. With a view to enhancing the virulence of the fungus, the effect of increasing endogenous oxalic acid concentration through modification of the growth conditions was investigated. S. minor was grown in 125 ml of eight different liquid culture media in shake flasks incubated at 20°C for 7 days. The final pH, mycelial dry weight, and oxalic acid content of the spent growth media were determined and the virulence of S. minor grown on each solid culture medium was screened on detached dandelion leaves. A 330% increase in oxalic acid was obtained plus 56 mM of sodium succinate to Modified Richard's solution (MRS) as compared to MRS alone. A concomitant increase in virulence of 218% was expressed as increased lesion diameter.     

"蒲公英-蝌蚪-鳝鱼"食物链的物流与能流分析

本文对食物链“蒲公英—蝌蚪—鳝鱼”的物质流和能量流作了定量分析。结果表明：该食物链经济产品的物质、能量转化效率较低,生物量转化效率为1.1％,能量转化效率为0．8％,N、P转化效率分别为3．1％、1．5％。但该食物链刺激鳝鱼食欲,有利于鳝鱼繁殖。     

Land-use selection by dandelions in the Tokyo metropolitan area,Japan

Land use by native and introduced dandelion groups in man-made habitats was studied at 7090 survey points in the Tokyo metropolitan area, Japan, in order to clarify the replacement phenomenon occurring among dandelions. In the center of Tokyo, where the native group was rare, the percentage occurrence of the introduced group was lower than in other regions, whereas in the outskirts of Tokyo, both groups showed much higher occurrence. Roadsides, vacant areas and urban land-use categories were significantly favorable for growth of the introduced group, whereas preserved or rural land use was more favorable for the native group. Seed fertility in the introduced group was more than 80%, and was independent of population size, whereas in the native group it was not as high, and for a small population was dependent on population size, being stable at about 70% in populations larger than 70 plants. Thus, both large populations and solitary plants in the introduced group appeared to act as seed sources, making it likely that the introduced group will spread increasingly through roadsides and urban land, which are becoming more widespread as a result of urbanization. It is feared that, unless deliberately retained, the amount of preserved or rural land which has fostered large populations of the native group will further decrease with urbanization and other forms of development, thus depleting the seed sources and reducing the population.     

Insect herbivory and plant adaptation in an early successional community*

To address the role of insect herbivores in adaptation of plant populations and the persistence of selection through succession, we manipulated herbivory in a long‐term field experiment. We suppressed insects in half of 16 plots over nine years and examined the genotypic structure and chemical defense of common dandelion (Taraxacum officinale), a naturally colonizing perennial apomictic plant. Insect suppression doubled dandelion abundance in the first few years, but had negligible effects thereafter. Using microsatellite DNA markers, we genotyped >2500 plants and demonstrate that insect suppression altered the genotypic composition of plots in both sampling years. Phenotypic and genotypic estimates of defensive terpenes and phenolics from the field plots allowed us to infer phenotypic plasticity and the response of dandelion populations to insect‐mediated natural selection. The effects of insect suppression on plant chemistry were, indeed, driven both by plasticity and plant genotypic identity. In particular, di‐phenolic inositol esters were more abundant in plots exposed to herbivory (due to the genotypic composition of the plots) and were also induced in response to herbivory. This field experiment thus demonstrates evolutionary sorting of plant genotypes in response to insect herbivores that was in same direction as the plastic defensive response within genotypes.     

Influence of substrate concentration and bicarbonate addition on the anaerobic digestion of an inulin-rich substrate as the ending stage in a dandelion biorefinery scheme

This study was focused on the suitability of dandelion plant as part of a biorefinery scheme in which anaerobic degradation (biomethanization) for biogas production is the ending process. Inulin as the main compound in the tuberous root was selected as substrate and tested at different concentrations (5, 10 and 15 g TS L⁻¹). The presence of bicarbonate as a buffer on anaerobic digestion was assessed as well. Methane production curves were fitted with the modified Gompertz equation. Methane production yield (Y_CH4), specific maximum methane production rate (SR_MAX) and the first-order hydrolysis constant (k_H) were affected by the substrate concentration. Bicarbonate was found not to be determinant for the overall biomethanization process because no significant effect over the Y_CH4was achieved in the presence or absence of bicarbonate; between 0.19 to 0.23 m³ kg^-1 VS added. However, k_Hand SR_MAX were affected by the presence of this inorganic compound. Without the addition of bicarbonate, k_Hand SR_MAX decreased as the TS increased. These results will be key for a dandelion biorefinery proof-of-concept under the proposed conditions.