黑鲷DMRT1基因cDNA片段的克隆和序列分析

根据其他鱼类DMRT1基因中的保守序列设计了一对简并引物 ,利用反转录 多聚酶链式反应 (RT PCR)的方法克隆了黑鲷 (Acanthopagrusschlegeli)DMRT1基因cDNA的一个片段 .该片段长 13 8bp ,推导的氨基酸序列由 45个氨基酸残基组成 .同源性分析表明 ,该cDNA片段与其他鱼类DMRT1基因序列具有较高的同源性     

基于包裹体信息分析准噶尔盆地柴窝堡凹陷芦草沟组储层油源及成藏期次

柴窝堡凹陷芦草沟组原油的研究工作取得了重要进展,但由于构造沉积演化十分复杂,目前油源方面的认识仍不清楚,成藏时间尚不明确。利用改进的石油包裹体烃组分分析方法和包裹体定年技术讨论了研究区芦草沟组原油的来源和成藏期次。结果表明,研究区芦草沟组储层第一期充注原油正构烷烃主峰碳数低,C₂₁三环萜烷和C₂₇甾烷相对丰度较高,显示蓝色荧光,为北部半深湖—深湖相芦草沟组烃源岩生成的高成熟原油,于早白垩世在达1井区聚集成藏;第二期充注原油正构烷烃主峰碳数高,C₂₀三环萜烷或C₂₃三环萜烷、C₂₉甾烷相对丰度较高,显示黄绿色、黄色荧光,为研究区滨浅湖相芦草沟组烃源岩生成的较低成熟度原油,于晚白垩世末期—古新世早期在达1井区聚集成藏。     

Carbon recombination lines from the Galactic plane at 34.5 & 328 MHz

We present the results of a search for carbon recombination lines in the Galaxy at 34.5 MHz (C575α) made using the dipole array at Gauribidanur near Bangalore. Observations made towards 32 directions resulted in detections of lines, in absorption at nine positions. Followup observations at 328 MHz (C272α) using the Ooty Radio Telescope detected these lines in emission. A VLA D-array observation of one of the positions at 330 MHz yielded no detection implying a lower limit of 10′ for the angular size of the line forming region. The longitude-velocity distribution of the observed carbon lines indicate that the line forming regions are located mainly between 4 kpc and 7 kpc from the Galactic centre. Combining our results with published carbon recombination line data near 76 MHz (Erickson, McConnell & Anantharamaiah 1995), we obtain constraintson the physical parameters of the line forming regions. We find thatif the angular size of the line forming regions is ≥ 4°, then the range of parameters that fit the data are:T _e =20–40 K,n _e ∼ 0.1–0.3 cm⁻³ and pathlengths ∼ 0.07–0.9 pc which may correspond to thin photodissociated regions around molecular clouds. On the other hand, if the line forming regions are ∼ 2° in extent, then warmer gas (T _e ∼ 60–300 K) with lower electron densities (n _e ∼ 0.03–0.05 cm⁻³) extending over several tens of parsecs along the line of sight and possibly associated with atomic HI gas can fit the data. Based on the range of derived parameters, we suggest that the carbon line regions are most likely associated with photo-dissociation regions.     

几种鱼类培养细胞对不同干扰素敏感性的研究

本文研究了四种鱼类培养细胞ＣＩＫ、ＣＡＢ、ＧＣＢ、ＢＲＥ对Ｈｕｉｆｎ－ａ,ＣＩＫ、ＣＡＢ、ＧＣＢ、ＧＲＥ、ＦＨＭ等五种鱼类培养细胞干扰素作用的敏感性。这四种鱼类培养细胞对ＨｕＩＦＮ－ａ不敏感,对五种鱼类培养细胞干扰素表现出相对一致的敏感性差异,其中ＧＲＥ细胞对鱼类干扰素最敏感,其次为ＣＡＢ、ＧＣＢ。ＣＩＫ细胞能产生高滴度的干扰素但对鱼类干扰素不敏感。不同病毒对干扰素作用的敏感性也不同。     

一种基于带通滤波的机场跑道提取方法

作为重要战略目标的机场跑道是一种重要的遥感图像提取目标。高分辨率遥感图像中机场跑道等地物人工标志线清晰可辨,可作为一种重要的地物提取标志。在建立机场跑道模型的基础上,提出了一种基于带通滤波的提取机场跑道人工标志线的算法,并建立了机场主跑道提取的技术流程。该流程包括非植被区提取、数学形态学处理、带通滤波、Douglas-Peucker平滑算法以及平行线对模型的建立等。利用该算法对6处机场进行了试验,结果表明该算法提取准确可靠。     

The nature and structure of the emission line nebula K 3-35: a very young planetary nebula with precessing bipolar jet-like outflows?

We present Hα, [N  II ]6583 and 6-cm continuum images of the emission line nebula K 3-35. The optical images reveal an extended nebula (size ≃ 11 × 9 arcsec² in [N  II ]) in which most of the emission originates in a very narrow (width 0.7–1.3 arcsec) S-shaped region which extends almost all along the nebula (≃ 7 arcsec). The 6-cm continuum emission also arises in this narrow region, which is characterized by an exceedingly high point-symmetry and systematic and continuous changes of the orientation with respect to the nebular centre. The properties of the narrow region suggest that it represents a system of precessing bipolar jet-like components. Two low-excitation, compact bipolar knots near the tips of the jet-like components are observed in the deduced [N  II ]/Hα image ratio. These knots may be generated by the interaction of the collimated outflows with surrounding material. A comparison of the optical and radio images shows the existence of differential extinction within the nebula. Maximum extinction is observed in a disc-like region which traces the equator of the elliptical shell previously observed at 20-cm continuum. All available data strongly suggest that K 3-35 is a very young planetary nebula in which we could be observing the first stages of the formation of collimated outflows and point-symmetric structures typically observed in planetary nebulae. The properties of the jet-like components in K 3-35 are in good agreement with models of binary central stars in which highly collimated outflows originate either from a precessing accretion disc or via magnetic collimation in a precessing star.     

Heterogeneity of the interstellar diamond in the CV3 meteorite Efremovka

Based on the heterogeneity in the contents and isotopic compositions of carbon, nitrogen, and rare gases found in different (in grain size) interstellar diamond fractions of the meteorite Efremovka, we discuss issues associated with the nature of the diamond, the distribution of the isotopic components of impurity chemical elements in it, and the kinetics of their release.     

Spectra of Comet Hale-Bopp (C/1995 O1) Obtained with 6-M BTA Reflector at Mount Pastukhov

Between July 1996 and April 1997, 92 spectra of comet Hale-Bopp were obtained with the 6-meter BTA telescope of the SAO of the RAS at Mount Pastukhov. The spectra are two-dimensional, which allows one to determine the energy distribution for each emission along the slit and the energy distribution in wavelength for each individual position in the slit. From the 92 two-dimensional spectra covering the inner coma, detailed spectral maps of the total near-nuclear region of the comet are available for July 10, 11 and 12, 1996 and April 15, 1997. We propose an hypothesis about an unknown cometary species near λ = 620 nm in the spectrum obtained July 10, 1996. We also find an effect which may be caused by fluorescence of cometary dust. This revised version was published online in July 2006 with corrections to the Cover Date.     

相对论喷束模型中表现速度计算的修正

在相对论喷束模型中，假设源的核在观测者静止坐标系中不动的前提下，推出了现在已得到广泛承认和采用的计算相对论等离子团横向视速度的公式．随着观测精度的提高，对核固定不动的假设提出了怀疑，认为有必要重新估价表现横向速度公式的正确性，并在更普遍的框架下，找出该公式的修正形式．本文试图对几种根据目前对射电源一般结构认识提出的模型，初步探讨这种修正的可行性．     

Searching for large-scale structure in deep radio surveys

We calculate the expected amplitude of the dipole and higher spherical harmonics in the angular distribution of radio galaxies. The median redshift of radio sources in existing catalogues is z  ∼ 1, which allows us to study large-scale structure on scales between those accessible to present optical and infrared surveys, and that of the cosmic microwave background (CMB). The dipole is a result of two effects which turn out to be of comparable magnitude: (i) our motion with respect to the CMB, and (ii) large-scale structure, parametrized here by a family of cold dark matter power-spectra. We make specific predictions for the Green Bank 1987 (87GB) and Parkes–MIT–NRAO (PMN) catalogues, which in our combined catalogue include ∼ 40 000 sources brighter than 50 mJy at 4.85 GHz, over about 70 per cent of the sky. For these relatively sparse catalogues both the motion and large-scale structure dipole effects are expected to be smaller than the Poisson shot noise. However, we detect dipole and higher harmonics in the combined 87GB–PMN_raw catalogue which are far larger than expected. We attribute this to a 2 per cent flux mismatch between the two catalogues. Ad hoc corrections made in an effort to match the catalogues may suggest a marginal detection of a dipole. To detect a dipole and higher harmonics unambiguously, a catalogue with full sky coverage and ∼ 10⁶ sources is required. We also investigate the existence and extent of the supergalactic plane in the above catalogues. In a strip of ± 10° of the standard supergalactic equator, we find a 3 σ detection in PMN_raw, but only 1 σ in 87 GB_raw. We briefly discuss the implications of ongoing surveys such as FIRST and NVSS and follow-up redshift surveys.