锡林河流域一个放牧草原群落土壤呼吸及其影响因子的研究

本文综述了草原群落土壤呼吸研究的理论、方法、最新进展和主要成果。从2001年6月5日到10月15日，在内蒙古锡林河流域的一个典型草原群落放牧地段用气相色谱法对土壤呼吸进行了测定，并同期观测相应的环境因子，分析了它们之间的相互关系，并根据根系生物量和土壤呼吸的相关性外推出根系呼吸占土壤总呼吸的比例。同时，采用碱液吸收法对该草原群落和一个沼泽化草甸群落的土壤呼吸进行了比对测定，比较在不同生境下土壤呼吸速率的差异。另外，重点比较了两种常用的土壤呼吸测量方法——碱液吸收法和气相色谱法对典型草原群落土壤呼吸的测量效果。主要研究成果如下： 1．在草原群落，生物量（包括地上和地下生物量）、温度（包括气温和土壤温度）和水分及土壤呼吸的季节变化均呈不规则的波动曲线;土壤呼吸与土壤湿度高度相关，与温度尤其是土壤温度以及地下生物量之间存在着一定的相关性，但和地上生物量及绿色生物量之间几乎没有关系。 2．草原群落和草甸群落土壤呼吸的季节动态基本一致，均出现了两个峰值，分别出现在6月底和7月底，它们的变化范围分别为312.8~1738.9 mg C﹒m-2﹒d-1 和 354.6 ~2235.6 mg C﹒m-2﹒d-1，日平均土壤呼吸速率分别为785.9 mg C﹒m-2﹒d-1 和1349.6 mg C﹒m-2﹒d-1，草甸群落的土壤呼吸速率明显高于草原群落; 3．土壤水分是草原群落土壤呼吸的主要限制因子，但对草甸群落的土壤呼吸变化却基本没有影响;草甸群落中，地上总生物量与土壤呼吸速率间没有显著的相关关系，但地上部分绿色生物量与土壤呼吸间存在着显著的幂函数关系，而在草原群落中，土壤呼吸速率与地上活生物量或地上总生物量的相关关系均很弱。 4．在草原群落，根系呼吸占土壤总呼吸的比例为60.7% - 93.3%，平均为82%; 5．碱液吸收法和气相色谱法的测定结果具有很高的相关性（R2=0.7563），它们的季节动态基本一致，变化范围分别为从249.3~1795.1 mg C﹒m-2﹒d-1和从312.8~1738.9 mg C﹒m-2﹒d-1，平均值分别为634.2 mg C﹒m-2﹒d-1和802.7 mg C﹒m-2﹒d-1，碱液吸收法的测量值是气相色谱法的约1.4倍。

Real time feature-based facial tracking using Lie algebras

We have developed a novel human facial tracking system that operates in real time at a video frame rate without needing any special hardware. The approach is based on the use of Lie algebra, and uses three-dimensional feature points on the targeted human face. It is assumed that the roughly estimated facial model (relative coordinates of the three-dimensional feature points) is known. First, the initial feature positions of the face are determined using a model fitting technique. Then, the tracking is operated by the following sequence: (1) capture the new video frame and render feature points to the image plane; (2) search for new positions of the feature points on the image plane; (3) get the Euclidean matrix from the moving vector and the three-dimensional information for the points; and (4) rotate and translate the feature points by using the Euclidean matrix, and render the new points on the image plane. The key algorithm of this tracker is to estimate the Euclidean matrix by using a least square technique based on Lie algebra. The resulting tracker performed very well on the task of tracking a human face.

大蹼铃蟾皮肤肽及其制备方法和在制药中的应用

本发明属于生物医学领域。大蹼铃蟾皮肤肽，是从中国两栖类动物大蹼铃蟾皮肤分泌物中分离得到的一种单链多肽，分子量2674.2，等电点9.8，多肽全序列一级结构为：NH2—GIGTKILGGVKTALKGALKELASTYAN－NH2。其制备方法是将活体大蹼铃蟾用水清洗干净，置于带盖的玻璃容器中，滴加无水乙醚，密闭容器3—5分钟，可见大量的泡沫状物质从大蹼铃蟾皮肤分泌出来，收集分泌物，离心去除沉淀、冷冻干燥后，经离子交换、凝胶过滤柱层析分离纯化后得到。大蹼铃蟾皮肤肽作为制备治微生物感染疾病药物、肿瘤治疗药物的应用。具有显著的抑制细菌和真菌生长、肿瘤细胞抑制活性高等优点。

Ultrafast switching liquid crystals for electro-optic transmissive and reflective displays and microscopic lasers

We have used novel liquid crystals with extremely large flexoelectric coefficients in a range of ultra-fast photonic/display modes, namely 1) the uniform lying helix, that leads to in-plain switching, birefringence based displays with 100 μs switching times at low fields, i.e.2-5 V/μm, wide viewing angle and analogue or grey scale capability, 2) the uniform standing helix, using planar surface alignment and in-plane fields, with sub ms response times and optical contrasts in excess of 5000:1 with a perfect black "off state", 3) the wide temperature range blue phase that leads to field controlled reflective color and 4) high slope efficiency, wide wavelength range tunable narrow linewidth microscopic liquid crystal lasers.

Mineralogical variations and physical properties of deep sea sediments, northwest Arabian Sea

Charles Darwin the research ship undertook an Oceanographic Cruise in 1986, CD 86/17 of the North Arabian Sea. Sediment cores were collected between 15° and 25°N. In this study sediment cores collected from deep Indus and Oman basins (CD 1715, CD 1730, CD 1738) have been analyzed for mineralogy, water content and porosity. In general, the cores are mainly composed of clay to silt sized terrigenous and biogenic constituents. Quartz, Chlorite and Illite are the common minerals of Arabian Sea sediments. Porosity determined by water content of sediments has been correlated with quartz/chlorite and quartz/illite peak ratios to show a relationship between mineral composition and physical properties.

Dinoflagellate "brown tides" in Alexandria, Egypt waters during 1997-1998

Charles Darwin the research ship undertook an Oceanographic Cruise in 1986, CD 86/17 of the North Arabian Sea. Sediment cores were collected between 15° and 25°N. In this study sediment cores collected from deep Indus and Oman basins (CD 1715, CD 1730, CD 1738) have been analyzed for mineralogy, water content and porosity. In general, the cores are mainly composed of clay to silt sized terrigenous and biogenic constituents. Quartz, chlorite and illite are the common minerals of Arabian Sea sediments. Porosity determined by water content of sediments has been correlated with quartz/chlorite and quartz/illite peak ratios to show a relationship between mineral composition and physical properties.

云南绵羊染色体比较研究

本文研究了云南昭通、德钦、腾冲绵羊染色体的核型、Ｇ带、Ｃ带、Ａｇ－ＮＯＲ，结果表明：云南绵羊染色体众数２ｎ＝５４；染色体Ｇ带基本相似；Ｃ带显示三个绵羊品种染色体亚中着丝粒区均为淡染，近端着丝粒区均为深染，Ｘ和Ｙ性染色体整个都为淡染，产在三个地区的绵羊其染色体异染色质的大小、强弱存在差异；Ａｇ－ＮＯＲｓ的数目分布在２～１０之间，众数为７，腾冲绵羊Ａｇ－ＮＯＲｓ较粗大，而昭通、德钦绵羊的较为细小，反映出云南绵羊在进化过程中有不同的分化。

Spatio-temporal clustering of probabilistic region trajectories

We propose a novel model for the spatio-temporal clustering of trajectories based on motion, which applies to challenging street-view video sequences of pedestrians captured by a mobile camera. A key contribution of our work is the introduction of novel probabilistic region trajectories, motivated by the non-repeatability of segmentation of frames in a video sequence. Hierarchical image segments are obtained by using a state-of-the-art hierarchical segmentation algorithm, and connected from adjacent frames in a directed acyclic graph. The region trajectories and measures of confidence are extracted from this graph using a dynamic programming-based optimisation. Our second main contribution is a Bayesian framework with a twofold goal: to learn the optimal, in a maximum likelihood sense, Random Forests classifier of motion patterns based on video features, and construct a unique graph from region trajectories of different frames, lengths and hierarchical levels. Finally, we demonstrate the use of Isomap for effective spatio-temporal clustering of the region trajectories of pedestrians. We support our claims with experimental results on new and existing challenging video sequences. © 2011 IEEE.

大型水电站对河流底栖藻类群落的影响

2004年9月—2007年6月,对古夫河受大型水电站影响的GF04样点及高岚河的参照样点GL03进行逐月采样,研究了大型水电站对古夫河底栖藻类的影响.结果表明:研究期间,两样点主要理化指标差异均不显著(P>0.05);两样点水动力学差异显著(P<0.05),研究期间GL03样点基本处于缓流状态,其季节变化显著(P<0.05),而GF04样点由于受水库放水影响,采样期间60%以上时间处于急流状态,没有明显的季节节律,说明水动力学及生境的变化是影响研究区底栖藻类群落的重要因素;群落相似性以及非着生型硅藻、直立

雌核发育银鲫原肠期胚胎和尾芽期胚胎差异表达基因的呈现

构建了雌核发育银鲫原肠期胚胎和尾芽期胚胎间的抑制性差减杂交cDNA质粒文库。对原肠期739个 和尾芽期816个PCR阳性克隆进行斑点杂交,得到72个原肠期和98个尾芽期斑点杂交阳性克隆。测序和基因 数据库比对结果表明:72个原肠期斑点杂交阳性克隆中,包括19个已知基因的cDNA片段和31个没有同源性的 cDNA片段;98个尾芽期斑点杂交阳性克隆中,包括52个已知基因的cDNA片段和37个没有同源性的cDNA片 段。采用虚拟Northern杂交和RT PCR证实了部分基因在银鲫胚胎发育过程中的差异表达。这些

ZnO nanostructures grown on AlN/sapphire substrates by MOCVD

ZnO nanorods and nanotubes are successful synthesized on AlN/sapphire substrates by metal-organic chemical vapour deposition (MOCVD). The different morphology and structure properties of ZnO nanorods and nanotubes are found to be allected by the AlN under-layer. The photoluminescence spectra show the optical properties of the ZnO nanorods and nanotubes, in which a blueshift of UV emission is observed and is attributed to the surface effect.

Stretchable Graphene: A Close Look at Fundamental Parameters through Biaxial Straining

Tunable biaxial stresses, both tensile and compressive, are applied to a single layer graphene by utilizing piezoelectric actuators. The Gruneisen parameters for the phonons responsible for the D, G, 2D and 2D' peaks are studied. The results show that the D peak is composed of two peaks, unambiguously revealing that the 2D peak frequency (omega(2D)) is not exactly twice that of the D peak (omega(D)). This finding is confirmed by varying the biaxial strain of the graphene, from which we observe that the shift of omega(2D)/2 and omega(D) are different. The employed technique allows a detailed study of the interplay between the graphene geometrical structures and its electronic properties.