Chemically decoupled nuclei in five lenticular galaxies from SAURON data

We analyze data from the SAURON integral-field spectrograph of the William Herschel 4-m telescope for five lenticular galaxies in which we previously found chemically decoupled nuclei from observations with the Multipupil Fiber Spectrograph of the 6-m Special Astrophysical Observatory telescope. In a larger field of view, we confirmed the presence of peaks of the equivalent width of the Mg Ib λ5175 absorption line in the nuclei of all five galaxies. However, the structure of the chemically decoupled regions turned out to be highly varied even in such a small sample: from compact unresolved knots to disks with an extent of several hundred parsecs and, in one case, a triaxial compact minibar-type structure. We confirmed the presence of an inner gaseous polar ring in NGC 7280 and found it in NGC 7332. In their outer parts, the planes of these polar rings are warped toward the plane of stellar rotation in such a way that the gas counterrotates with respect to the stars. This behavior of the gas in a triaxial potential was predicted by several theoretical models.     

Infrared luminosities of local-volume galaxies

Based on data from the Two-Micrometer All-Sky Survey (2MASS), we analyzed the infrared properties of 451 Local-Volume galaxies at distances D ≤ 10 Mpc. We determined the K-band luminosity function of the galaxies in the range of absolute magnitudes from ?25^m to ?11^m. The local luminosity density within 8 Mpc is 6.8 × 10⁸L_⊙ Mpc^?3, a factor of 1.5 ± 0.1 higher than the global mean K-band luminosity density. We determined the ratios of the virial mass to the K-band luminosity for nearby groups and clusters of galaxies. In the luminosity range from 5 × 10¹⁰ to 2 × 10¹³L_⊙, the dependence log(M/L_K) ∝ (0.27 ± 0.03) log L_K with a dispersion of ～0.1 comparable to the measurement errors of the masses and luminosities of the systems of galaxies holds for the groups and clusters of galaxies. The ensemble-averaged ratio, 〈M/L_K〉 ? (20–25) M_⊙/L_⊙, was found to be much smaller than the expected global ratio, (80–90)M_⊙/L_⊙, in the standard model with Ω_m = 0.27. This discrepancy can be eliminated if the bulk of the dark matter in the Universe is not associated with galaxies and their systems.     

The Ursa Major supercluster of galaxies: I. The luminosity function

Catalogs of bright galaxies in the central regions of 11 clusters in the Ursa Major supercluster are presented. Absolute and relative coordinates and total B and R magnitudes are given for each galaxy. Plates taken with the 2-m Tautenburg Observatory telescope and CCD images obtained with the 6-m and 1-m SAO telescopes are used. The luminosity functions (LFs) for galaxies in the cluster nuclei (3 Mpc×3 Mpc) and the composite LF for the supercluster are constructed. The composite LF is well fitted by a Schechter function with $M_B^ * = - 20\mathop .\limits^m 91$ , α=?1.02 and with $M_R^ * = - 22\mathop .\limits^m 39$ , α=?1.06. A comparison with the LFs of field galaxies and of various samples of clusters and superclusters shows that the Ursa Major supercluster have LF parameters characteristic of the field and, thus, differ from those of the Corona Borealis supercluster, which is apparently at a later stage of dynamical evolution.     

天宝山多金属矿床地球化学模式

天宝山铅锌矿山正处于资源枯竭状态,在该矿山附近寻找新的矿床对天宝山矿山来说是当务之急。我们对现有的区域地球化学和地质资料进行分析研究,总结出天宝山多金属矿床的水持地球化学异常特征、地球化学异常分带模式及地球化学找矿模式,在此基础上,提出了光新屯找远景区。     

大气层臭氧损耗与紫外辐射对海洋浮游植物的影响

人类活动产生的氟氯烃等化合物对大气的污染造成臭氧损耗 ,引起地面紫外辐射 ( UV-B)增加 ,进而造成对生物的有害影响。根据作者近年来的研究和国际上的相关研究进展 ,本文就“臭氧洞”形成和紫外辐射增加对海洋浮游植物影响的关键所在 ,即紫外辐射对海洋浮游植物的生化效应 ,包括海洋生物对 UV- B的忍耐性和抵御能力、UV- B对海洋浮游植物细胞内、外生化环境的影响等 ,作一综述。     

Standing stock of phytoplankton and primary productivity in Penaeus orientalis larval multiplication releasing area of the Xiangshan Bay

INTRODUCTIONTheXiangshanBayisoneoftheimportantmarineaquaculturebasesinZhejiang.Since1982,themultiplicationreleasingexperimentsofPenaeusorzentalisKishinouyelarvalhavebeencarriedoutinthebay.Thestudyonthephytoplankton,chlaconcentrationandproductivityandthelifepatternofreleasedlarvaeprawnintheXiangshanBayisoneoftheimportanttasksoftheNationalKeyProject--AquaticExploitationTechniqueResearchinLakesandHarbors.TherearemanylargebaysandharborsalongChina'scoast,butonlyafewobservationshavebeend…     

A comparison of iron limitation of phytoplankton in natural oceanic waters and laboratory media conditioned with EDTA

The solubility of iron in oxic waters is so low that iron can be a limiting nutrient for phytoplankton growth in the open ocean. In order to mimic low iron concentrations in algal cultures, Ethylenediaminetetraacetate (EDTA) is commonly used. The presence of EDTA enables culture experiments to be performed at a low free metal concentration, while the total metal concentrations are high. Using EDTA provides for a more reproducible medium. In this study Fe speciation, as defined by EDTA in culture media, is compared with complexation by natural organic complexes in ocean water where Fe is thought to be limited. To grow oceanic species into iron limitation, a concentration of at least 10⁻⁴ M EDTA is necessary. Only then does the calculated [Fe³⁺] concentrations resemble those found in natural sea water, where the speciation is governed by natural dissolved organic ligands at nanomolar concentrations. Moreover, EDTA influences the redox speciation of iron, and thus frustrates research on the preferred source of Fe-uptake, Fe(III) or Fe(II), by algae. Nowadays, one can measure the extent of natural organic complexation in sea water, as well as the dissolved Fe(II) state, and can use ultra clean techniques in order to prevent contamination. Therefore, it is advisable to work with more natural conditions and not use EDTA to create iron limitation. This is especially important when the biological availability of the different chemical fractions of iron are the subject of research. Typically, many oceanic algae in the smallest size classes can still grow at very low ambient Fe and are not easily cultivated into limitation under ambient sea water conditions. However, the important class of large oceanic algae responsible for the major blooms and the large scale cycling of carbon, silicon and other elements, commonly has a high Fe requirement and can be grown into Fe limitation in ambient seawater.     

莫莫格湖泊群近50年来的环境变化

莫莫格源泊群水痊和生态环境的变化,主要取决于大气降水和河流水位的变化,近５０年来,湖区气温逐渐上升,在自然因素和人为活动的影响下,源泊水位有逐渐下降的趋势,源泊生态环境不断恶化。     

土体工程地质层组的划分

工程地质岩组的划分是岩体质量评价的基础。当大型工程揭露土层很多时,进行土体工程地质层组的划分亦是十分必要的。它可以更为清晰的反映场地地质结构的变化规律,便于地质模型的概化和参数研究,有助于抓住主要工程地质问题进行评价,便于设计师的理解和应用。以南京地铁南北线一期工程为例,探讨了土体工程地质岩组的划分问题。通过以层组为基础的参数离散性统计、工程地质模型与工程地质问题的分析可以看出该层组划分方案的合理性与工程意义。     

一种基于微博签到数据的城市功能区复合程度探究方法

城市功能区复合程度是城市发展规划、评价城市区域发展均衡性的重要参考。本文以深圳市为研究对象,首先,划分渔网单元与微博签到数据求交计算样方单元各类签到数据比例。其次,采用香农熵对复合程度进行定量化描述并连接渔网赋予属性值。最后,基于Arc GIS由粗至细进行可视化呈现和分析。结果表明,提出的方法能够有效地表示城市功能区的复合情况,具有较强的可操作性。