民族院校中专业野外实习教学模式的设计与实践

野外实习是生物科学、生态学专业实践教学中的重要环节,在巩固学生学校所学理论知识及培养和提高学生实际动手能力等方面具有重要意义.本文以在民族地区自然保护区野外实习的有益实践及获得的良好实习效果,提出生物科学、生态学专业开展研究与教学结合的野外实习教学模式.     

一种改进的差分酉空时编码技术

差分酉空时码不需要任何信道状态信息，在通信终端处于高速移动环境下的快变衰落信道中仍能保持较好的性能。传统的差分酉空时码仅考虑了单电平发射功率，限制了高信噪比时性能的提高。通过在码字内引入多电平相位因子，提出了一种两发射天线以上的多电平差分酉空时码星座构造方案，扩大了码字之间的最小距离，提高了星座的分集乘积。仿真结果表明在译码复杂度略高的情况下改进方案的性能比传统差分酉空码有明显的改善。     

巢湖十五里河河口湿地植物群落多样性分析

依据巢湖十五里河河口植物群落野外调查资料,运用PCORD软件中Euclidean距离和Ward’s meth-od聚类方法研究了河口湿地植物群落的特征及多样性变化;用收获法研究了植物群落的生物量变化。研究显示:十五里河河口湿地植物群落由21个种组成,它们隶属于18属,11科,其中假稻(Leersia japonica)、北水苦荬(Veronica anagallis aquatica)、长芒野稗(Echinochloa caudata)、芮草(Beckmannia syzigachne)、黄花蒿(Artemisia annua)和水花生(Alternanthera philoxeroides)为优势种;河口湿地植物群落可分为8个组合,其中分布在湖堤附近的黄花蒿 北水苦荬(Artemisia annua Veronica anagallis aquatica)组合多样性指数和均匀度指数最高,分别为2.06和0.94;组合中物种多样性指数与物种丰富度和均匀度指数线性相关性不明显,其相关系数分别为0.609和0.549;组合的分布、生物量和多样性均与水位变化有密切关系。     

陕西秦岭地区兽类多样性分析

陕西秦岭山地是东洋界和古北界的交汇地带,物种多样性较为丰富.有兽类7目28科82属125种,占陕西省兽类总种数的85.0%.兽类区系组成十分复杂:北方分布型有57种,南方分布型有68种,特有种23种.列入国家重点保护名录、中国物种红色名录和CITES附录的物种有54种,占该区总种数的43.2%.这些珍稀、特有动物主要分布在秦岭地区15个自然保护区内.导致众多物种濒危的原因,主要是栖息地变化和人猎杀等.     

Determination of the optical thickness and effective particle radius of clouds from transmitted solar radiation measurements

A method is presented for determining the optical thickness (τc) and effective particle radius (re) of stratiform cloud layers from transmitted solar radiation measurements. A detailed study shows that the cloud optical thickness and effective particle radius of water clouds can be determined from transmission function measurements at 0.75 and 2.13 μm, provided that the scaled optical thickness τ′0.75>1 and re>5 μm. The wavelengths adopted by our study are similar to the channels of the moderate resolution imaging spectrometer (MODIS). The proposed method is invalid for optically thin clouds since transmission at 2.13 μm is less sensitive to re. The retrieval errors of τ′0.75 and re monotonically decrease with increasing τc. For clouds having τ′0.75≥2, the retrieval errors of τ′0.75 and re are below 10% and 20%, respectively. Transmissions at 0.75 and 1.65 μm can also be used to retrieve τc and re.     

High variability of the gvpA-gvpC region in Microcystis

Gas vesicles provide buoyancy to Microcystis and other common cyanobacterial bloom-forming species. gvpA and gvpC are structural genes encoding gas vesicle proteins. Phylogenetic analyses of 10 Microcystis strains/uncultured samples showed that gvpC and each intergenic segment of the gvpA-gvpC region can be divided into two types. The combination of different types of gvpC and intergenic segments is an important factor that diversifies this genomic region. Some Microcystis strains isolated in China possess a 172 to 176 bp sequence tag in the intergenic segment between gvpA and gvpC. The gvpA-gvpC region in Microcystis can be divided into at least 4 classes and more numbers of subclasses. Compared to rbcLX and other regions, the high variability of the gvpA-gvpC region should be more useful in identifying geographical isolates or ecotypes of Microcystis.     

河南省粮食生产地域差异的分析研究

本文从粮食产量和粮食增长速度两个方面分析了河南省粮食生产的地域差异,指出抓紧抓好粮食生产,实现区域产需平衡是全省国民经济发展中的重要任务,继续增加投入是粮食稳定增长的关键性环节;高产低速和低产低速区粮食增产潜力较大,应作为近期投资的重点区域。     

影响侏罗纪双壳动物群分异度的主要因素

古大西洋地区侏罗纪双壳动物群分异度的变化主要受沉积相的多样性和相类型、温度梯度、盐度以及海平面变化的影响．在这些环境因素的控制下，双壳类分异度的分布特点主要表现在：①位于中纬度地区的法国北部和英国南部地区分异度值最高，由此向南向北逐渐降低；②低纬度地区的分异度高于高纬度地区；③尽管经历了２次下降期，在Ｋｉｍｍｅｒｉｄｇｉａｎ期前双壳类分异度总的变化趋势是逐渐增高的，并在Ｋｉｍｍｅｒｉｄｇｉａｎ期达到最大．此后，开始第３次下降期     

Behavioural and morphological dimorphism of the sexes: an account of two primitively eusocial wasps

In social Hymenoptera, foraging, nest building, brood care and all other colony maintenance functions are carried out by the females while males function solely as reproductives. This asymmetry in social roles of the two sexes has led social insect researchers to focus almost exclusively on the females whereas males have remained relatively neglected. We studied two sympatric, primitively eusocial wasps, Ropalidia marginata and Ropalidia cyathiformis, and compared the morphological and behavioural profiles of males and females. Males of both species are smaller in size and weigh less compared to females. Males of the two species live in the nest for different durations. Borrowing from the ecological literature we use novel methods to compute and compare behavioural diversity and behavioural richness and show that females of both species are behaviourally richer and more diverse than the males.     

V-BLAST-based demodulate-and-forward two-way relaying： protocol design and the detection

We propose a novel vertical Bell Laboratories layered space-time (V-BLAST) based two-way relaying protocol that comprises two user terminals and one multi-antenna demodulate-and-forward (DMF) relay station. We consider the situation when these two user terminals employ different modulation types and investigate its detection techniques. The key feature of the detection techniques is that we quantify decision reliability at the relay station by introducing a so-called normalized correlation coefficient (CORR), rather than having full confidence in demodulation at the relay station. With the assistance of the normalized correlation coefficient, we develop detection methods at both the relay station and user terminals. In particular, we propose a CORR-based ordering algorithm at the relay station which can be applied to detection for general V-BLAST architectures. Simulation results demonstrate the superiority of the CORR-based ordering algorithm over the conventional signal-to-noise based ordering algorithm. Finally, we demonstrate overall error-performance of the V-BLAST-based DMF two-way relaying protocol via simulations.