农村税费改革形势下灌区清淤工作探讨

对灌区渠道清淤群众投工历史进行了回顾，论述了税费改革试点工作以来渠道清淤的现状，对下一步清淤工作的思路进行了探讨。     

A deficiency of the homeotic complex of the beetle Tribolium

In Drosophila, the establishment of regional commitments along most of the anterior/posterior axis of the developing embryo depends on two clusters of homeotic genes: the Antennapedia complex (ANT-C) and the bithorax complex (BX-C). The red flour beetle has a single complex (HOM-C) representing the homologues of the ANT-C and BX-C in juxtaposition. Beetles trans-heterozygous for two particular HOM-C mutations spontaneously generate a large deficiency, presumably by an exchange within the common region of two overlapping inversions. Genetic and molecular results indicate that this deficiency spans at least the interval between the Deformed and abdominal-A homologues. In deficiency homozygous embryos, all gnathal, thoracic and abdominal segments develop antennal appendages, suggesting that a gene(s) has been deleted that acts to distinguish trunk from head. There is no evidence that beetles have a homologue of the segmentation gene fushi tarazu of similar genomic location and function. On the basis of the genetic tractability, convenient genome size and organization of Tribolium, and its relatively long phylogenetic divergence from Drosophila (>300 million years), we have integrated developmental genetic and molecular analyses of the HOM-C. We isolated about 70 mutations in the complex representing at least six complementation groups. The homeotic phenotypes of adults and lethal embryos lead us to believe that these beetle genes are homologous with the Drosophila genes indicated in Fig. 1 (see text).     

A new interstellar molecule: tricarbon monoxide

The cold dark interstellar Taurus Molecular Cloud One (TMC-1) is a rich source of acetylenic and polyacetylenic molecular species. As well as linear closed-shell molecules (H(C triple bond C)nCN) and symmetric rotors (CH3C triple bond CH, CH3C triple bond CCN), several radicals (C triple bond CH, C triple bond CCN, (C triple bond C2H) have also been identified, many of which had not been studied previously in the laboratory. Whether the observed abundances can be understood in terms of purely gas-phase ion-molecule chemical schemes, which produce reasonable agreement for the simplest polyatomic species, is unclear; alternative models involving the particulate interstellar grains as catalysts or sources have also been suggested. We now report the detection in TMC-1 of a new molecule, tricarbon monoxide (C3O), whose pure rotational spectrum has only very recently been studied in the laboratory. As C3O is the first known interstellar carbon chain molecule to contain oxygen, its existence places an important new constraint on chemical schemes for cold interstellar clouds. In fact, the observed abundance of tricarbon monoxide fits quite well into our model of galactochemistry.     

Serum enzyme activities in the African elephant (Loxodonta africana)

Summary The serum activities of aspartate aminotransferase, alanine aminotransferase, -hydroxybutyrate dehydrogenase and creatine phosphokinase have been measured in the African elephant. In general, the values were broadly comparable with those of man except that alanine aminotransferase was much lower and creatine phosphokinase higher. No variation due to age, sex, season or location was observed.     

微机械加工中恒温腐蚀系统的设计研究

本文设计了一个恒温腐蚀系统，用于微机械加工制作中的腐蚀工艺．系统装备了冷凝回流与加热搅拌装置，保证了腐蚀过程中，腐蚀液浓度的稳定与均匀；特殊设计的加热设备，提高了热量的利用效率．同时，采用内藏式温度传感器和基于模糊专家系统的温度控制算法，使腐蚀系统的温度控制更加精确、灵活．与传统水浴恒温相比，不仅使用方便，而且提高了腐蚀的效率与质量．     

二相编码信号调制分析与识别

针对采用脉冲压缩体制的低截获概率雷达的应用场合,提出了一种识别二相编码脉冲压缩雷达信号的新算法。该算法基于信号的时频分析(小波分析和短时傅里叶变换),利用小波变换的相位尺度和载波尺度的模极大值特征辨识信号的相位调制规律,因而在无需计算全部小波系数的情况下,可快速地获得信号的数学模型,为算法在实际中的应用提供了良好的条件。给出了应用该方法的具体步骤,通过计算机仿真实验证明该算法的有效性。     

《百合花》中叙述者"我"的重要作用

《百合花》主要刻画的是小通讯员与新媳妇之间的圣洁感情,但两者之间穿针引线的是小说叙事人“我”。从结构上说,两个主人公是被言说者,他们的心理世界是通过叙事者“我”的眼睛看出来或感受到的,小说使用的是外聚焦叙事法,叙述者“我”在结构上有举足轻重的地位和作用,“我”的叙事视角也新颖独特,匠心独运,令人耳目一新,回味不尽。