Molecular identification and culture observation on <Emphasis Type="Italic">Acrochaete leptochaete</Emphasis> (Chaetophoraceae,Chlorophyta) from China

Acrochaete leptochaete (Huber) Nielsen (Chaetophoraceae, Chlorophyta) was isolated from the macroalgae Chaetomorpha collected from intertidal pools in Rongcheng, Shandong, China. 18S rDNA combined with ITS regions were used to ascertain the morphological identification of the isolated material. Based on the unialgal culture, asexual reproduction and growth characteristics of A. leptochaete were investigated over wide ranges of temperature and irradiance. Results revealed that asexual reproduction of A. leptochaete could be realized by biflagellate zoospores. The zoospores germinated directly to give self- replicating generations. Zoospore germination was bipolar. A temperature range from 13-21°C and a lower irradiance of 36 μmol/(m2·s) were most favorable for the growth of A. leptochaete. Thallus organization, an important taxonomic criterion for the genus Acrochaete, was affected markedly by temperature and irradiance. Our results extend the knowledge about the species’ general biology and its morphological plasticity. For classification and identification of a simple microphytic algae like A. leptochaete, which are traditionally placed in the class Chaetophoraceae, we propose that molecular tools associated with culture observations are applied.     

陆态网VLBI站坐标解算

介绍“中国大陆构造环境监测网络”VLBI站坐标解算的方法和过程.采用1994-2009年共50次观测数据解算台站及基线的年变化率,得到了台站的坐标及基线的年变化,并给出了VLBI站坐标解算的统计分析结果.     

Diversity and bioactivity of actinomycetes from marine sediments of the Yellow Sea

Among the 116 actinomycetes collected from marine sediments of the Yellow Sea,56 grew slowly and appeared after 2?3 weeks of incubation.Among the 56 strains,only 3 required seawater(SW) for growth,and 21 grew well in the medium prepared with SW rather than distilled water(DW),while the remaining 32 grew well either with SW or with DW.Six representatives with different morphological characteristics,including 1 SW-requiring strain and 5 well-growing with SW strains,were selected for phy-logenetic analysis based on 16S rRNA gene.Two strains belong to Micrococcaceae and Nocardiopsaceae respectively.The other 4 strains belong to the family of Streptomycetaceae.In the analyzed 6 strains,one was related to Nocardiopsis spp.and the other three were related to Streptomyces spp.,representing new taxa.Bioactivity testing of fermentation products from 3 SW-requiring strains and 21 well-growing with SW strains revealed that 17 strains possessed remarkable activities against gram-positive pathogen or/and tumor cells,suggesting that they were prolific resources for natural drug discovery.     

A comprehensive evaluation of tourism climate suitability in Qinghai Province, China

Qinghai Province is an important component of the Qinghai-Tibet Plateau in China. Scientific evaluation of the suitability of Qinghai’s climate for tourism can contribute to overcoming obstacles posed by climate on sustainable tourism development in Qinghai Province, including disparities between the low and high seasons, high altitude health concerns, and weather events. A tourism climate suitability evaluation model of the Qinghai-Tibet Plateau is constructed (Tourism Climate Suitability Index, or TCSI), and tourism climate suitability is comprehensively evaluated for Qinghai Province from climate data from 1960 to 2009. Results show that: (I) There is clear distributional characteristics of spatial-temporal variability of TCSI values in Qinghai Province. (II) Tourism climate suitability in Qinghai Province has significant seasonal and regional differences. The year is divided into a very suitable period (July and August), suitable tourism periods (from April and October), less suitable periods (From Nov to Mar). June to August is the most suitable tourism period in Qinghai. Qinghai Province is divided into five levels of tourism climate suitability: most suitable regions, very suitable regions, suitable regions, less suitable regions, and unsuitable region. (III) The key factor which influences regional differences in tourism climatic suitability is atmospheric oxygen. And the key factors which chiefly influence seasonal differences of tourism climate suitability are temperature and humidity, the wind chill factor, and barrier weather.     

Subsurface flow processes in sloping cropland of purple soil

Subsurface flow is a prominent runoff process in sloping lands of purple soil in the upper Yangtze River basin.However,it remains difficult to identify and quantify.In this study,in situ runoff experimental plots were used to measure soil moisture dynamics using an array of time domain reflectometry(TDR) together with overland flow and subsurface flow using isolated collecting troughs.Frequency of preferential flow during rainfall events and the controls of subsurface flow processes were investigated through combined analysis of soil properties,topography,rainfall intensity,initial wetness,and tillage.Results showed that subsurface flow was ubiquitous in purple soil profiles due to welldeveloped macropores,especially in surface soils while frequency of preferential flow occurrence was very low(only 2 cases in plot C) during all 22 rainfall events.Dry antecedent moisture conditions promoted the occurrence of preferential flow.However,consecutive real-time monitoring of soil moisture at different depths and various slope positions implied the possible occurrence of multiple subsurface lateral flows during intensive storms.Rainfall intensity,tillage operation,and soil properties were recognized as main controls of subsurface flow in the study area,which allows the optimization of management practices for alleviating adverse environmental effects of subsurface flow in the region.     

基于L1范数凸二次规划方法的航空重力测量数据稀疏重构（英文）

由于受到国界、测量成本和数据规模等因素的限制,航空重力测量本质上是一种欠奈奎斯特采样方法,本文通过离散傅里叶变换分析了航空重力测量的稀疏性,提出了利用压缩感知理论实现大规模重力异常数据高精度重构的思路。基于压缩感知理论,重力异常数据重构问题可以转化为基于L1范数的凸二次规划问题,本文结合预处理共轭梯度算法,提出了一种改进的内点法来解决此问题。进一步地,我们利用自主研发的SGA-WZ型捷联式航空重力仪在中国某地区进行了航空重力测量试验。通过对试验中测得的重力异常数据进行重构,与常用的线性插值重构方法对比,结果表明:本文提出的基于压缩感知理论的新方法能够以更高的重构精度,更有效地解决大规模重力异常数据的重构问题。     

从工程实践浅析基桩高应变法检测承载力误差问题

高应变法检测是基桩检测技术的一种重要手段,但是该方法检测承载力存在误差,因此受到许多争议。本文以广东惠州地区两项工程的检测实践为例,分别采用前后两组不同拟合参数,对检测数据进行了承载力拟合计算,分别得出了前后两种不同的计算结果。并通过动、静两种方法的对比检测,分析了高应变法检测承载力误差产生的主要原因,粗略探讨了对高应变法检测的一些认识。     

新疆巴楚和塔什库尔干地震台下方地壳结构研究

Using the teleseismic waveform data recorded by the seismic station Bachu( hereafter referred to as station BCH) i n the Tarim Basin and the seismic station Taxkorgan(h ereafter referred to as station TAG) i n the west Kunlun Mountains for years,we applied the receiver function H-κ stacking method to study the crustal structure beneath stations BCH and TAG. The results showed that there are obvious differences in the crustal thickness beneath stations BCH and TAG,and the regional crustal thickness and terrain have a very good corresponding relationship. There are high crustal average V P/ V S values beneath the two stations. The crustal thickness is 44 km,and the crustal average wave velocity ratio is 1. 849 beneath station BCH. There is a sharp discontinuity in the middle of the crust beneath station BCH at a depth of 21 km. There is a low average P wave velocity and low V P/ V S from the surface to the discontinuity beneath station BCH.The depth of the discontinuity is consistent with the lower interface of the focal depth from accurate location in the Jiashi earthquake source area adjacent to station BCH; and may be the crustal brittle-ductile conversion boundary. The crustal thickness is 69 km,and the crustal average wave velocity ratio is 1. 847 beneath station TAG,a thicker crust and high V P/ V S may indicate that materials in the lower crustal are prone to plastic flow,which is responsible for the thickening of the crust.     

Detrital apatite fission track analyses of the Subei basin: implications for basin-range structure of the northern Tibetan Plateau

The northern Tibetan Plateau has evolved a unique basin-range structure characterized by alternating elongated mountain ranges and basins over a history of multiple tectonic and fault activities. The Subei basin recorded evolution of this basin-range structure. In this study, detailed detrital apatite fission track (AFT) thermochronological studies in conjunction with previously documented data reveal provenance of the Subei basin, important information about the Indo-Eurasia collision, and two Miocene uplift and exhumation events of the northern Tibetan Plateau. Detrital AFT analyses combined with sedimentary evidences demonstrate that the Danghenanshan Mountains is the major provenance of the Subei basin. In addition, very old age peaks indicate that part sediments in the Subei basin are recycling sediments. Age peak populations of 70–44 Ma and 61–45 Ma from the lower and upper Baiyanghe formations record the tectono-thermal response to the Indo-Eurasia collision. Combined detrital AFT thermochronology, magnetostratigraphy and petrography results demonstrate the middle Miocene uplift and exhumation event initiated 14–12 Ma in the Subei basin, which may resulted from the Miocene east-west extension of the Tibetan Plateau. Another stronger uplift and exhumation event occurred in the late Miocene resulted from strengthened tectonic movement and climate. A much younger AFT grain age, breccia of diluvial facies and boulders of root fan subfacies record the late Miocene unroofing in the Danghenanshan Mountains.     

U–Pb dating of zircon and cassiterite from the Early Cretaceous Jiaojiguan iron-tin polymetallic deposit,implications for magmatism and metallogeny of the Tengchong area,western Yunnan,China

The newly discovered Jiaojiguan deposit, a medium-scale skarn iron-tin polymetallic deposit on the Sino-Burma boundary of Yunnan Province (SW China), is spatially associated with the biotite monzonitic granite. Here, we report new in situ zircon LA-MC-ICP-MS U–Pb ages, trace element and Hf isotope data from the granite, and U–Pb dating ages of cassiterite from the ore bodies. In this study, we obtain a weighted mean ²⁰⁶Pb/²³⁸U age of 124.1 ± 1.4 Ma for the zircon and a ²⁰⁷Pb/²⁰⁶Pb-²³⁸U/²⁰⁶Pb intercept age of 123.8 ± 2.2 Ma for the cassiterite. The granite crystallized during the Early Cretaceous, with zircons exhibiting εHf(t) values from ?5.8 to ?0.6 and two-stage Hf model ages (T_DM2) of 1.21–1.54 Ga. The close temporal and spatial links between pluton emplacement and ore-forming events suggest that magmatic-hydrothermal events were the key factors that triggered the genesis of the iron-tin polymetallic deposits in the area. Regional geochronological data show that tin mineralization took place three times during the Cretaceous–Palaeogene in the Tengchong block due to re-melting of the underlying supposed Proterozoic (1.5 ± 0.5 Ga) Sn-rich strata/materials. Compared with those in the Bangong–Nujiang metallogenic belt (BNMB), we propose that the Cretaceous iron-tin polymetallic mineralization events in Tengchong–Baoshan closely resemble those of the Bangong–Nujiang belt in northern Tibet, both of which have experienced similar tectono-magmatic-metallogenic histories since the Mesozoic.