基于欧氏距离的农业可持续发展评价理论构建与实例验证

基于欧氏距离构建了农业可持续发展评价理论体系,包括农业可持续发展模型、评价函数、评价等级、目标系统、零系统与评价指标框架。选取宁夏吴忠市2000—2012年数据开展了实例验证,可持续发展指数(ASDI)范围是[0.65,0.70],呈现平缓上升趋势,呈现中持续发展状态。评价结果基本反映了农业系统情况,表明基于欧氏距离构建农业可持续发展评价方法是可行的。该方法的创新性与优势表现在:一是具有可靠的方法论;二是构建了农业可持续发展模型,引入目标系统与零系统概念,建立了农业可持续发展评价参照系,提升了评价的可控性;三是数学函数中隐含了指标权重,回避专家打分法引起的误差或错误,也回避了由于指标增减中指标权重不得不重新赋值的专家打分法缺陷;四是可持续发展评价指数采用函数模型转换,把欧氏距离转换成百分数值一方面易理解,另一方面不同系统的指数值能够进行相互比较。宁夏吴忠农业可持续发展水平偏低的主要原因是氮肥施用量高、秸秆还田率低、复合肥或专用肥比例低、保护性农作技术推广不够、土壤有机质低以及农村人均收入偏低等。     

Modelling bird habitat suitability based on landscape parameters at different scales

Habitat suitability as characterized by the presence of a species and by reproductive success was modelled in relation to different parameters of landscape diversity at different scales. Parameters characterizing landscape pattern were determined for the UTM 10 km × 10 km cells covering the whole of Estonia and were correlated to the distribution of over 30 forest bird species. The landscape parameters include areas of lakes, mires and built-up areas, length of borders between different land cover units and length of selected line elements, share of different kinds of forest and peatland. The bird species are grouped by correlation into three major groups: (a) independent, (b) wetland preferring (with subgroups of those avoiding built-up areas and roads and those not) and (c) built-up area dependent (with subgroups depending on the importance of line elements). For selected predator species, nesting success was related to landscape parameters on a finer scale, using cells of 10 km². Land pattern was characterized by total length of line elements (streams, roads, borders, ecotones) and certain areal coverage (forest, mires, fields, built-up areas) within the cell. The impact of variations of food availability was linked to the relation. Possibilities for downscaling and upscaling of relations determined at different scales and areal coverage are discussed.     

Vasomotion: the case for chaos

Fluctuations in vascular calibre, a phenomenon known as vasomotion, are ubiquitous in the microcirculation and represent emergent behaviour that involves synchronisation of Ca²⁺ oscillations in individual vascular cells. Ideally, coordinated interactions between locally generated vasomotion and neuro-humoral control mechanisms will allow optimal sensing of flow and pressure within vascular networks and thereby facilitate synergistic readjustments in local vascular conductance and flow under conditions of dynamically changing metabolic demand. Indeed, many studies have reported that vasomotion becomes more prominent under pathophysiological conditions, suggesting that it may serve as an adaptive homeodynamic response that maintains or re-establishes flow when perfusion is compromised. We here summarise evidence that the apparent irregular nature of vasomotion reflects deterministic interactions between a small number of dominant control variables, rather than random events, and may therefore be formally classified as chaotic. We also discuss the potential physiological benefits of chaos in the microcirculation and the key roles of signalling via gap junctions and nitric oxide.     

Combining stratification and up-scaling method-block cokriging with remote sensing imagery for sampling and mapping an erosion cover factor

When a ground and vegetation cover factor related to soil erosion is mapped with the aid of remotely sensed data, a cost-efficient sample design to collect ground data and to obtain an accurate map is required. However, the supports used to collect ground data are often smaller than the desirable pixels used for mapping, which leads to complexity in developing procedures for sample design and mapping. For these purposes, a sampling and mapping method was developed by integrating stratification and an up-scaling method in geostatistics — block cokriging with Landsat Thematic Mapper imagery. This method is based on spatial correlation and stratified sampling. It scales up not only the ground sample data but also the uncertainties associated with the data aggregation from smaller supports to larger pixels or blocks. This method uses the advantages of both stratification and block cokriging variance-based sample design, which leads to sample designs with variable grid spacing, and thus significantly increases the unit cost-efficiency of sample data in sampling and mapping. This outcome was verified by the results of this study.     

Scale dependence of landscape metrics and their indicatory value for nutrient and organic matter losses from catchments

We investigated scale dependence of landscape metrics and the relationship between land use parameters and FRAGSTATS-based landscape metrics (edge density (ED), patch density (PD), mean shape index (SHAPE_MN), mean euclidean nearest neighbor index (ENN_MN), contagion (CONTAG), patch richness density (PRD), and Shannon's diversity index (SHDI)) and nutrient/organic-matter-based water quality indicators (BOD₇ and COD_KMnO4 values, total-N and total-P concentrations in water) in 24 catchments with various land use patterns in Estonia. We used the Basic Map of Estonia (1:10,000), the Base Map of Estonia (1:50,000) and the CORINE Land Cover Map (1:100,000). In scale analysis, we calculated landscape metrics on artificial and real landscapes. Scale analysis showed that responses of landscape metrics to changing grain size vary among landscapes and metrics. Analysis of artificial landscapes showed that mean euclidean nearest neighbor distance and contagion are directly dependent on grain size and should therefore be used carefully. When finding relationships between landscape metrics and water quality indicators, significant differences between the relationships derived from the Base Map and the CORINE Land Cover Map were found. In the case of the Base Map, landscape metrics correlated strongly with land use and showed no expected relationships with water quality data. This underlines the importance of land use classification in such kind of analysis. Correlation between the landscape metrics calculated on the basis of the CORINE Land Cover Map and water quality data was stronger than in the case of the Base Map. The COD_KMnO4 value significantly correlated with all land use types. For instance, the COD_KMnO4 values are higher when fens and natural areas form a higher proportion of the catchments’ land use. Except for the BOD₇ value, all the water quality indicators showed significant correlation with urban land use proportions. Strong relationship between the patch density and the COD_KMnO4 value is most likely caused by the fact that both parameters were significantly correlated with the proportion of natural areas. As the landscape metrics depend on pixel size, topographic scale, and land use classification, and as the effect of land use on water quality in catchments is the most significant of the factors, it was impossible to separate the influence of land use pattern from the influence of FRAGSTATS-based landscape metrics.     

Effects of body mass and temperature on routine metabolic rate of juvenile largemouth bronze gudgeon Coreius guichenoti

The effects of body mass (M) and temperature (T) on routine metabolic rate (m(R) ) were assessed in the largemouth bronze gudgeon Coreius guichenoti, from Three Gorges Reservoir, Yangtze River, China. The m(R) increased with increasing M by factors (b-value in the equation m(R) = aM(b) ) of 0·843, 0·800, 0·767, 0·788 and 0·822 at 10, 15, 20, 25 and 30° C, respectively. A significant interaction between M and T on m(R) was observed. The variation in the b-value at different T suggests that the b-values were not consistent with the universal allometric exponent 0·75. After controlling for M, the relationship between the normalized standard metabolic rate (m(S), mg O(2) kg(-1) h(-1)) and T was described by an exponential equation: m(S) = 9·89e((0·093T)) . The results indicate that the effects of M on m(R) depend on T. The increased water temperature induced by dam construction on the Yangtze River may cause a marked increase in energy demand by this species, with potential ecological consequences.     

Modelling the drought impact on monoterpene fluxes from an evergreen Mediterranean forest canopy

In many ecosystems drought cycles are common during the growing season but their impact on volatile monoterpene emissions is unclear. Therefore, we aimed to develop and evaluate a process-based modelling approach to explore the explanatory power of likely mechanisms. The biochemically based isoprene and monoterpene emission model SIM-BIM2 has been modified and linked to a canopy model and a soil water balance model. Simulations are carried out for Quercus ilex forest sites and results are compared to measured soil water, photosynthesis, terpene-synthase activity, and monoterpene emission rates. Finally, the coupled model system is used to estimate the annual drought impact on photosynthesis and emission. The combined and adjusted vegetation model was able to simulate photosynthesis and monoterpene emission under dry and irrigated conditions with an R ² of 0.74 and 0.52, respectively. We estimated an annual reduction of monoterpene emission of 67% for the extended and severe drought period in 2006 in the investigated Mediterranean ecosystem. It is concluded that process-based ecosystem models can provide a useful tool to investigate the involved mechanisms and to quantify the importance of specific environmental constraints.     

Fine-structured multi-scaling long-range correlations in completely sequenced genomes—features,origin, and classification

The sequential organization of genomes, i.e. the relations between distant base pairs and regions within sequences, and its connection to the three-dimensional organization of genomes is still a largely unresolved problem. Long-range power-law correlations were found using correlation analysis on almost the entire observable scale of 132 completely sequenced chromosomes of 0.5 × 10⁶ to 3.0 × 10⁷ bp from Archaea, Bacteria, Arabidopsis thaliana, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Drosophila melanogaster, and Homo sapiens. The local correlation coefficients show a species-specific multi-scaling behaviour: close to random correlations on the scale of a few base pairs, a first maximum from 40 to 3,400 bp (for Arabidopsis thaliana and Drosophila melanogaster divided in two submaxima), and often a region of one or more second maxima from 10⁵ to 3 × 10⁵ bp. Within this multi-scaling behaviour, an additional fine-structure is present and attributable to codon usage in all except the human sequences, where it is related to nucleosomal binding. Computer-generated random sequences assuming a block organization of genomes, the codon usage, and nucleosomal binding explain these results. Mutation by sequence reshuffling destroyed all correlations. Thus, the stability of correlations seems to be evolutionarily tightly controlled and connected to the spatial genome organization, especially on large scales. In summary, genomes show a complex sequential organization related closely to their three-dimensional organization. This article has been submitted as a contribution to the festschrift entitled “Uncovering cellular sub-structures by light microscopy” in honor of Professor Cremer’s 65th birthday.     

三峡库区宜昌至泄滩段水质污染现状及对策

通过对长江三峡库区宜昌至泄滩段水域污染情况的实地调查和水质分析,采用单因子水质类别法和综合污染指数法对其水质污染现状进行分析、横纵向比较和评价,结论为三峡库区水域污染在1999年出现峰值,现在总体上呈好转趋势,水质总体评价级别为Ⅱ类,水体污染以有机物和重金属污染及细菌为主,主要污染源为沿江工业和城市生活污水。水质好转的客观原因主要在于管理和治理力度加大。     

The link between metabolic rate and body temperature in galliform birds in thermoneutral and heat exposure conditions: The classical and phylogenetically corrected approach

Three galliform species (grey partridges, ring-necked pheasants, and king quail) were involved in body temperature and resting metabolic rate measurements over a broad range of ambient temperatures (20–45 °C). At thermoneutrality, inter-species differences in colonic temperature, as well as in metabolic rate, were observed. During heat exposure, all species reacted by elevating their body temperatures above 44 °C, thereby inducing temporary hyperthermia. Heat-stressing birds resulted in a slightly increased metabolic rate in king quail, but not in partridges and pheasants. Based on data of body temperature and weight specific (per body mass unit) basal metabolic rate among ten species of Galliformes order, classical and phylogenetically corrected analyses of covariation between these two physiological traits were performed. The scaling of body temperature to body mass, revealed a significant exponent of: −0.0062 and −0.0080 for conventional and phylogenetical methods, respectively. In the analyzed species, a strong positive relationship between residuals of body mass values between body temperature and metabolic rate were found. The results obtained may show a plausible evolutionary link between these traits in galliform birds.