Significance of long chain iso and anteiso monomethyl alkanes in the Lamiaceae (mint family)

The potential significance of the contributions of long chain iso and anteiso monomethyl alkanes (LC MMAs) from plants of the Lamiaceae, a family that includes many culinary and aromatic herbs of cultural value, to sediments and soil has been evaluated by analyzing 21 specimens from 16 species of Lamiaceae from different environmental settings in Hubei Province, central China, and comparing the results with those from tobacco plants, which are established to be rich in these compounds. Odd numbered iso-alkanes (i-C₂₅ to i-C₃₆) and even numbered anteiso-alkanes (a-C₂₅ to a-C₃₆) are abundant in the Lamiaceae (1.9-23.2% and 0.9-23.8% of total alkanes, respectively). The proportions of LC MMAs are relatively high and comparable to those in the tobacco plant. However, chain lengths in the Lamiaceae are longer than those in tobacco plants and compound-specific δ¹³C values are more negative than in the tobacco plants, potentially allowing distinction of their different origins. The results imply that Lamiaceae, in addition to some other land plants, can be important sources of LC iso- and anteiso-alkanes in sediments and soils.     

Linkage between winter air temperature over the subtropical Western Pacific and the ice extent anomaly in the Sea of Okhotsk

This study deals with the correlation between ice extent in the Sea of Okhotsk and the interannual variability of winter (December–February) air temperature over the subtropical Western Pacific from 1979 to 2008. The analysis indicates that the increase in sea ice extent coincides not only with cooling over the Sea of Okhotsk and the adjacent area, but also with significant warming over the subtropical Western Pacific that extends from the surface to the middle troposphere. This meridional dipole pattern of tropospheric temperature anomalies (cooling in the high latitudes and warming in the low latitudes) primarily results from dynamical processes driven by the large-scale atmospheric circulation change. A heat budget diagnosis reveals that when ice extent in the Sea of Okhotsk increases by one standard deviation, the tropospheric air temperature over the subtropical Western Pacific rises by about 0.25°C. It also suggests that the adiabatic heating and stationary eddy heat flux convergence may be the most important factors, which account for 30 and 15% of the warming, respectively. In addition, these two factors also coordinate to result in significant cooling over the Sea of Okhotsk and the adjacent regions.     

Constraints the properties of neutron star matter from the mass of neutron star PSR J1614-2230

The constraints on the properties of neutron star matter from the mass of neutron star PSR J1614-2230 are examined in the framework of the relativistic mean field theory. We find that there are little differences between the σ potentials of large mass neutron star and those of canonnical mass neutron star. For potentials of ω, ρ, neutrons and electrons, the values corresponding to the large mass neutron star are larger than those to the canonnical mass neutron star as the baryon number density is more than a certain value. We also find that for the relative particle number density of electrons, muons, neutrons and protons and the pressure of the neutron star, the values corresponding to the large mass neutron star are far larger than those to the canonnical mass neutron star. For the relative particle number density of hyperons Λ, Σ^?, Σ⁰, Σ⁺ and Ξ^?, the values corresponding to the large mass neutron star are far smaller than those to the canonnical mass neutron star. These mean that the larger mass of neutron star is more advantageous to the production of protons but is not advantageous to the production of hyperons.     

基于大数据的生活圈范围与服务设施空间匹配研究——以北京为例

生活圈建设是新时代国土空间规划的关键内容之一,生活圈内服务设施配置是做好生活圈规划的首要基础,居民生活圈与服务设施的空间匹配关系也是地理学“人地关系”在城市社区尺度的重要体现.学术界对生活圈与服务设施的匹配关系已有研究,但主要采用问卷调查数据,该类数据存在样本量少、地域覆盖范围小等不足.论文将采用手机信令数据和POI(...     

东太平洋地区DSDP573孔始新世末期的微玻璃陨石

通过研究 DSDP5 73孔的岩心样品 ,首次在该孔始新世与渐新世的界线地层含金属粘土层中发现了微玻璃陨石 ,且主要富集在其底部。一个样品 (5 g)中最多可达 12粒。这些微玻璃陨石主要呈球形、椭球形。用电子探针测试了其化学成分 ,Si O2 含量为 2 9.6 4%～ 5 8.93%,Al2 O3 为 3.42 %～ 2 0 .96 %,Fe O为 9.98%～ 2 9.5 5 %,Mg O为 4.32 %～ 16 .0 5 %,Ir为 0 .0 6 %～ 0 .81%。总体来说 ,微玻璃陨石的化学成分变化较大 ,可能与靶岩的成分变化较大有关。始新世末期北美微玻璃陨石场的展布方向约为 2 5 0°,这与太平洋板块运动方向改变所需要的矢量变化(2 45°)仅相差 5°,推测很可能是始新世末期陨星的撞击引起了太平洋板块在该时期的运动方向由 NNW突然变为NWW。     

中西部地区承接产业转移的影响因素研究

将中西部地区划分为东北、中部、西北、西南4个区域,采用1995—2013年的相关数据,分析各区域在承接东部发达地区产业转移过程中的主要影响因素。选取的影响因素包括资本存量、经济规模、劳动力成本、人力资源和路径效应。结果发现:4个区域的路径效应、资本存量与产业转移承接地均存在显著正相关关系;人力资源与产业转移承接地存在正相关关系,但东北、西北地区不显著;劳动力成本与产业转移承接地存在负相关关系,但对东北地区不显著;除中部地区外,经济规模与产业转移承接地并不存在显著相关关系。中西部区域地方政府和企业家在促进产业转移进程中应充分发挥比较优势,根据不同影响要素制定宏观政策与微观引资策略。     

三江平原旱田耕作对湿地土壤理化性质的累积影响初探

在中国科学院三江平原湿地生态试验站综合实验场,对不同耕作年限的湿地土壤(0~20 cm)进行环境累积效应分析。结果表明,随着开垦时间的增加,土壤的理化性质发生渐变,物理性质方面,土壤容重和比重逐渐增大,而孔隙度和田间持水量逐年减少;化学性质方面,土壤pH值随开垦时间的增加而增加,有机质和其他养分则随开垦时间的增加而逐年降低。弃耕后土壤性质有所恢复。土壤性质在开垦初期变化较明显,而后逐渐变缓。     

Massively parallel spatial point pattern analysis: Ripley’s K function accelerated using graphics processing units

This study presents a massively parallel spatial computing approach that uses general-purpose graphics processing units (GPUs) to accelerate Ripley’s K function for univariate spatial point pattern analysis. Ripley’s K function is a representative spatial point pattern analysis approach that allows for quantitatively evaluating the spatial dispersion characteristics of point patterns. However, considerable computation is often required when analyzing large spatial data using Ripley’s K function. In this study, we developed a massively parallel approach of Ripley’s K function for accelerating spatial point pattern analysis. GPUs serve as a massively parallel platform that is built on many-core architecture for speeding up Ripley’s K function. Variable-grained domain decomposition and thread-level synchronization based on shared memory are parallel strategies designed to exploit concurrency in the spatial algorithm of Ripley’s K function for efficient parallelization. Experimental results demonstrate that substantial acceleration is obtained for Ripley’s K function parallelized within GPU environments.     

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Responses of primary productivity to current and climate changes in the mud area to the southwest of Cheju Island during the past 800 years

The biogenic silica (BSi), total organic carbon (TOC), total nitrogen (TN) and grain size were analyzed with a gravity core (3250-6) collected from the mud area in the north East China Sea. The average deposition rate of the upper core was about 0.078 cm yr^?1 based on the results of ²¹⁰Pb_ex. The mean grain size increased with depth in general. The frequency distribution of grain size showed that two marked changes of deposition environment occurred at 30 cm and 50 cm depths (about 1550 AD and 1300 AD, respectively). The variations of BSi and TOC indicated two distinct major periods of primary productivity over the past 800 years: a stage of low primary productivity corresponding to weak upwelling and low nutrient input below 30 cm depth (about 1200–1550 AD), and a stage of high primary productivity with strong currents and upwelling above 30 cm depth (about 1550–1950 AD). The stage with high primary productive appeared to be due to the northward-expanded muddy area caused by strong Asian Winter Monsoon and enhanced Yellow Sea Warm Current in winter. In conclusion, the BSi and TOC in the muddy sediments, the symbols of marine primary productivity, can be then used to investigate the evolution history of currents and relative climate change in the offshore areas.