喀斯特山地城市内山体绿地对城市热岛的减温效应——以安顺市西秀区为例

山体绿地是喀斯特山地城市内典型的城市绿地景观类型,其对于改善城市生态环境、提升喀斯特山地城市生态服务功能具有重要作用.以黔中典型喀斯特山地城市安顺市为研究对象,运用2011年和2016年两期热红外遥感影像和城市景观结构空间数据,在反演分析城市热岛效应及其强度时空分布特征的基础上,运用冷热点分析剖析了山体绿地与城市热岛效...     

罗布泊地区第四纪环境演化

新疆罗后干涸湖盆中的Ｋ１钻孔揭示,１００、２ｍ的沉积剖面共有９２个宙积层,划归１６同积旋回,包括了早更新世以来的各时期沉积。据划分的１５个孢粉组这及古地磁、１４＾Ｃ、岩石地层资料综合分析,早更新世该区曾发育森林－草原植被,早更民末,强烈的构造运动保留我下更充变形,上覆的中更统与下更新统间呈不整合接触。中更新世,荒漠和荒漠草原交替出现,地层中有大量膏质泥岩和石膏。晚更新世以来,在干旱气候的控制之下,     

用RDA技术寻找肝再生相关基因的初步研究

利用表达性差异显示分析 (RDA)技术 ,研究大鼠 2 /3肝部分切除后 1h肝组织中基因的选择性表达 ,建立了大鼠 2 /3肝部分切除术后 1h再生肝组织选择性表达基因EST库。该库约含 3× 10 4 个独立克隆 ,其中 95 %以上的克隆含有插入片段 ,长度约 2 0 0～ 70 0bp不等 ,对随机挑出的 5 2个克隆的序列分析表明其中大多数基因与肝再生调控相关 (38/5 2 )。 10株未报道序列经RNA杂交证实 ,其中 6株与肝再生相关。     

Soil seed bank in a patchy vegetation of coastal sandy plains in southeastern Brazil

Large seed banks have been found in tropical dry forests and also in habitats with high seasonality in rainfall. However, patchily structured vegetation could induce great spatial variation in the seed bank. We characterized the seed bank in a patchy vegetation of restinga, a common type of coastal vegetation found in the Atlantic forest biome. We also evaluated whether there is any spatial variation between the litter and soil layer, bare sand, and the edge and center of vegetation patches with distinct species dominance. We found 104 seeds/m² in the seed bank using a 5‐cm‐depth sampling. Seven out of 16 species found in the restinga seed bank germinated; two of these were found in the early stages of vegetation patches. We found a higher number of seeds at the edge than in the center of vegetation patches. However, there were no significant differences in the number of seeds in the seed bank between the litter and soil layer, and between vegetation patches with distinct species dominance. Bare sandy soils had lower seed bank densities than vegetation patches. A small seed bank size might be explained by the low proportion of seeds from herbaceous and woody species, which are pioneers in the Atlantic forest. However, seed bank might play an important role in the early stages of the successional process, due to the occurrence of the few species that are able to colonize new young vegetation patches.     

Phylogenetic multilocus sequence analysis of native rhizobia nodulating faba bean (Vicia faba L.) in Egypt

The taxonomic diversity of forty-two Rhizobium strains, isolated from nodules of faba bean grown in Egypt, was studied using 16S rRNA sequencing, multilocus sequence analyses (MLSA) of three chromosomal housekeeping loci and one nodulation gene (nodA). Based on the 16S rRNA gene sequences, most of the strains were related to Rhizobium leguminosarum, Rhizobium etli, and Rhizobium radiobacter (syn. Agrobacterium tumefaciens). A maximum likelihood (ML) tree built from the concatenated sequences of housekeeping proteins encoded by glnA, gyrB and recA, revealed the existence of three distinct genospecies (I, II and III) affiliated to the defined species within the genus Rhizobium/Agrobacterium. Seventeen strains in genospecies I could be classified as R. leguminosarum sv. viciae. Whereas, a single strain of genospecies II was linked to R. etli. Interestingly, twenty-four strains of genospecies III were identified as A. tumefaciens. Strains of R. etli and A. tumefaciens have been shown to harbor the nodA gene and formed effective symbioses with faba bean plants in Leonard jar assemblies. In the nodA tree, strains belonging to the putative genospecies were closely related to each other and were clustered tightly to R. leguminosarum sv. viciae, supporting the hypothesis that symbiotic and core genome of the species have different evolutionary histories and indicative of horizontal gene transfer among these rhizobia.     

Variance-based sensitivity analysis of biological uncertainties in carbon ion therapy

PurposeBiological models to estimate the relative biological effectiveness (RBE) or the equivalent dose in 2 Gy fractions (EQD2) are needed for treatment planning and plan evaluation in carbon ion therapy. We present a model-independent, Monte Carlo based sensitivity analysis (SA) approach to quantify the impact of different uncertainties on the biological models.Methods and materialsThe Monte Carlo based SA is used for the evaluation of variations in biological parameters. The key property of this SA is the high number of simulation runs, each with randomized input parameters, allowing for a statistical variance-based ranking of the input variations. The potential of this SA is shown in a simplified one-dimensional treatment plan optimization. Physical properties of carbon ion beams (e.g. fragmentation) are simulated using the Monte Carlo code FLUKA. To estimate biological effects of ion beams compared to X-rays, we use the Local Effect Model (LEM) in the framework of the linear-quadratic (LQ) model. Currently, only uncertainties in the output of the biological models are taken into account.Results/conclusionsThe presented SA is suitable for evaluation of the impact of variations in biological parameters. Major advantages are the possibility to access and display the sensitivity of the evaluated quantity on several parameter variations at the same time. Main challenges for later use in three-dimensional treatment plan evaluation are computational time and memory usage. The presented SA can be performed with any analytical or numerical function and hence be applied to any biological model used in carbon ion therapy.     

松嫩平原破碎化羊草草甸退化演替系列植物多样性的空间格局

物种多样性格局是国际生物多样性科学前沿领域热点问题.本文以松嫩平原破碎化羊草草甸退化演替系列(6种植物群落、144个斑块)为研究对象,系统地探讨了其α、β和γ多样性空间格局及其机理.结果表明:在羊草草甸退化演替系列中共发现87种植物,但没有一种能分布于所有斑块;羊草+鸡儿肠群落或羊草群落的α、β和γ多样性较高,多稀有种和特有种;碱地肤群落最低,少稀有种,无特有种;γ多样性与α多样性显著正相关,但与β多样性无相关性.各植物群落的α多样性与单个斑块面积呈显著幂函数关系,β多样性(相似性指数Sjk)仅羊草+鸡儿肠群落呈显著幂函数关系;斑块平均面积和总面积与α、γ多样性呈显著正相关,与β多样性无相关性.群落的物种丰富度越高,稀有种和特有种就越多,物种在局域斑块上灭绝的可能性越大;β多样性在物种多样性格局中的重要性与生境破碎化程度有关.     

Numerical analyses of RAPD data highlight the origin of cultivated tagasaste (Chamaecytisus proliferus ssp. palmensis) in the Canary Islands

Random Amplified Polymorphic DNA (RAPD) was used to generate molecular markers to trace the origin of the fodder legume tagasaste (Chamaecytisus proliferus (L. fil.) Link ssp. palmensis (H. Christ) Kunkel) in the Canary Islands. Results from multivariate analyses of data through Two Way Indicator Species Analysis (TWINSPAN) and Detrended Correspondence Analysis (DECORANA) showed that genotypes collected on the island of La Palma exhibited a wider range of variation than those from the other islands. This supports the existing hypothesis that tagasaste originated on La Palma and emphasizes the importance of conserving and evaluating germ plasm from this island.     

Auto-align - multi-modality fluorescence microscopy image co-registration

Multi-modality microscopes incorporate multiple microscopy techniques into one module, imaging through a common objective lens. Simultaneous or consecutive image acquisition of a single specimen, using multiple techniques, increases the amount of measurable information available. In order to benefit from each modality, it is necessary to accurately co-register data sets. Intrinsic differences in the image formation process employed by each modality result in images which possess different characteristics. In addition, as a result of using different measurement devices, images often differ in size and can suffer relative geometrical deformations including rotation, scale and translation, making registration a complex problem. Current methods generally rely on manual input and are therefore subject to human error. Here, we present an automated image registration tool for fluorescence microscopy. We show that it successfully registers images obtained via total internal reflection fluorescence (TIRF), or epi-fluorescence, and confocal microscopy. Furthermore, we provide several other applications including channel merging following image acquisition through an emission beam splitter, and lateral stage drift correction. We also discuss areas of membrane trafficking which could benefit from application of Auto-Align. Auto-Align is an essential item in the advanced microscopist's toolbox which can create a synergy of single or multi-modality image data.