Paleoenvironmental and Human Behavioral Implications of the Boegoeberg 1 Late Pleistocene Hyena Den, Northern Cape Province, South Africa

Boegoeberg 1 (BOG1) is located on the Atlantic coast of South Africa, 850 km north of Cape Town. The site is a shallow rock shelter in the side of a sand-choked gully that was emptied by diamond miners. Abundant coprolites, chewed bones, and partially digested bones implicate hyenas as the bone accumulators. The location of the site, quantity of bones, and composition of the fauna imply it was a brown hyena nursery den. The abundance of Cape fur seal bones shows that the hyenas had ready access to the coast. Radiocarbon dates place the site before 37,000 ¹⁴C yr ago, while the large average size of the black-backed jackals and the presence of extralimital ungulates imply cool, moist conditions, probably during the early part of the last glaciation (isotope stage 4 or stage 3 before 37,000 ¹⁴C yr ago) or perhaps during one of the cooler phases (isotope substages 5d or 5b) within the last interglaciation. Comparisons of the BOG1 seal bones to those from regional Middle Stone Age (MSA) and Later Stone Age (LSA) archeological sites suggest (1) that hyena and human seal accumulations can be distinguished by a tendency for vertebrae to be much more common in a hyena accumulation and (2) that hyena and LSA accumulations can be distinguished by a tendency for hyena-accumulated seals to represent a much wider range of individual seal ages. Differences in the way hyenas and people dismember, transport, and consume seal carcasses probably explain the contrast in skeletal part representation, while differences in season of occupation explain the contrast in seal age representation. Like modern brown hyenas, the BOG1 hyenas probably occupied the coast year-round, while the LSA people focused their coastal visits on the August–October interval when nine-to-eleven-month-old seals were abundant. The MSA sample from Klasies River Mouth Cave 1 resembles BOG1 in seal age composition, suggesting that unlike LSA people, MSA people obtained seals more or less throughout the year.     

喜马拉雅珠峰地区冬季大气气溶胶化学组分及光学特征

为了研究喜马拉雅山北坡冬季大气气溶胶化学组分、光学特征及来源,2017年11—12月在珠穆朗玛峰站(QOMS)共采集22个PM2.5样品.结果显示:PM2.5中包括水溶性离子(WSIs)、有机质(OM)、元素碳(EC)在内的所有检测成分,总质量浓度为(3.36±1.06)μg·m-3;有机碳(OC)、元素碳(EC)和水...     

电感耦合等离子体质谱-原子荧光光谱法研究上海口岸进口印度尼西亚煤炭微量元素的赋存形态特征

印度尼西亚是我国最大的煤炭进口国,本文应用电感耦合等离子体质谱、原子荧光光谱、直接测汞仪等技术分析了上海口岸31批进口印度尼西亚煤炭中的12种微量元素,结合数理统计方法研究该类煤炭中微量元素的赋存形态。结果表明,进口印尼煤炭中含有高汞煤、三级含砷煤,As、Hg的平均富集系数大于1,其迁移风险值得关注;Be、Cu、Mo、Cd、Sn、Pb含量均低于中国煤和世界煤炭的平均水平,体现出印尼煤炭低灰分的品质特征。12种微量元素和相关项目(灰分和全硫)可划分为3类:第一类归纳为黏土矿物吸附类,包括As、Be、Cr、Co、Ni、Cu、Mo、Cd、Sn、Pb、灰分;第二类归纳为硫铁矿类,包括Hg、全硫;第三类归纳为碳酸盐矿物类,包括Ba。本文研究结果对于指导进口煤炭开发、利用过程中的环境评价和洁净化处理具有一定的参考价值。     

秦皇岛入海河流的污染水平、排放特征及对褐潮暴发区生源要素的影响

为查明秦皇岛近海大面积褐潮连年暴发的成因,在2013年3—11月对该地区主要入海河流和沿岸褐潮暴发区的生源要素污染进行了连续调查研究。调查结果表明,所调查入海河流普遍为劣V类地表水,总氮(TN)超标严重,按照氮污染程度由高到低排列依次为大蒲河洋河戴河石河汤河东沙河。各河流中的碳、氮、磷、硅等污染物浓度在时间变化上没有统一规律。基于综合污染指数法的评价结果显示,大蒲河和洋河为重度污染,戴河和汤河从先前的轻度污染加重为中度污染。从污染物入海量上看,TN和化学需氧量(COD)是排放量最高的两种河源污染物,其中溶解态氮占TN的74.6%。在所调查河流中,洋河和大蒲河分别贡献了TN的38.2%和33.2%,同时大蒲河还贡献了75.8%的活性磷酸盐和37.7%的活性硅酸盐,而75.9%的COD来自汤河、洋河和大蒲河。秦皇岛河源污染物排放在时间上较为集中在6—9月的丰水期,但各河流单独的排放具有随机性,没有统一的季节性规律,表现出受人为调控影响明显的特点。秦皇岛沿岸褐潮暴发区的生源要素变化与河源污染物排放有显著性相关(P=0.05)。     

自燃煤有机地球化学特征研究

通过有机地球化学研究，发现神府、焦坪、灵武三种自燃煤的ＣＨ２Ｃｌ２抽提率、族组分组成、有机地球化学参数有较大的差别。色谱曲线表现为两种类型，即单峰型和双峰型。生物标志物组合也有较大的差别。由于这种有机地球化学特征的不同，导致了自燃煤的自燃属性的不同。因而，有机地球化学方法可以用于自燃煤的研究。     

Herbig-Haro objects—tracers of the formation of low-mass stars and sub-stellar objects

Herbig-Haro objects (HHOs) are caused by outflows from young objects. Since the outflow relies on mass accretion from a circumstellar disk, it indicates ongoing growth. Recent results of infrared observations yielded evidence for disks around brown dwarfs. This suggests that at least a certain fraction of brown dwarfs forms like stars. Thus, young sub-stellar objects might cause HHOs as well. We present selected results of a general survey for HHOs based on DSS-II plates and CCD images taken with the Tautenburg Schmidt telescope. Numerous young objects could be identified due to their association with newly detected HHOs. In some cases the luminosity is consistent with very low-mass stars or close to sub-stellar values. This holds for L1415-IRS and a few infrared sources embedded in other dark clouds (e.g., GF9, BHR111). The question on the minimum mass for outflow activity is addressed.     

Hotspots and a clumpy disc: variability of brown dwarfs and stars in the young σ Ori cluster

The properties of accretion discs around stars and brown dwarfs in the σ Ori cluster (age 3 Myr) are studied based on near-infrared (IR) time series photometry supported by mid-IR spectral energy distributions (SEDs). We monitor ∼30 young low-mass sources over eight nights in the J and K band using the duPont telescope at Las Campanas. We find three objects showing variability with J -band amplitudes  ≥0.5 mag  ; five additional objects exhibit low-level variations. All three highly variable sources have been previously identified as highly variable; thus, we establish the long-term nature of their flux changes. The light curves contain periodic components with time-scales of  ∼0.5–8 d  , but have additional irregular variations superimposed – the characteristic behaviour for classical T Tauri stars. Based on the colour variability, we conclude that hotspots are the dominant cause of variations in two objects (#19 and #33), including one likely brown dwarf, with spot temperatures in the range of 6000–7000 K. For the third one (#2), a brown dwarf or very low-mass star, inhomogeneities at the inner edge of the disc are the likely origin of variability. Based on mid-IR data from Spitzer , we confirm that the three highly variable sources are surrounded by circum-(sub)-stellar discs. They show typical SEDs for T Tauri-like objects. Using SED models, we infer an enhanced scaleheight in the disc for the object #2, which favours the detection of disc inhomogeneities in light curves and is thus consistent with the information from variability. In the σ Ori cluster, about every fifth accreting low-mass object shows persistent high-level photometric variability. We demonstrate that estimates for fundamental parameters in such objects can be significantly improved by determining the extent and origin of the variations.     

改性黏土对褐潮生物种Aureococcus anophagefferens的去除研究

褐潮是一种由微微型藻引发的藻华,已连续4年在渤海海域暴发,给当地带来巨大的经济损失。目前,在褐潮尚不能有效预防、预控情况下,如何控制和减少其对生态环境和沿海经济带来的危害,成为一个急需解决的问题。利用改性黏土消除藻华是一种快速有效、并得以多次现场成功应用的方法。考察比较了多种不同产地、不同类型的黏土及其改性后对褐潮生物种Aureococcus anophagef ferens(抑食金球藻)的去除效果,选取5种典型的黏土作为主要的实验材料,开展了不同条件下黏土及其改性后对A. anophagef ferens去除效率的影响研究。实验发现,因A. anophagef ferens个体微小、藻华时密度大,相同用量的黏土或改性黏土对其去除效率低于常见的硅藻、甲藻生物;不同类型黏土对其去除效率有影响,高岭土的去除效率高于蒙脱土;而黏土改性后对A. anophagef ferens的去除效率提高3倍以上。在此基础上,还考察分析了黏土粒径、分散介质等因素对A. anophagef ferens去除效率的影响,为进一步研发安全、高效的褐潮应急消除材料做了有益探索。     

高煤级煤粗粒体反射率的演化轨迹

通过系统测试，查明了镜质体油浸最大反射率在２．０％～１０．０％之间的样品中粒粒体反射率的演化轨迹，发现其最大反射率的演化具有“转折”特征。粗粒体化学结构的“非石墨化碳”性质、物理结构的“富微孔性”及构造应力的作用是控制反射率演化的主要因素。     

Two nearby M dwarf binaries from the Two Micron All Sky Survey

We report the discovery of two binary M dwarf systems in the immediate solar neighbourhood using the Two Micron All Sky Survey (2MASS). The first is an M6.5 companion to the nearby G star HD 86728 (Gl 376). The known properties of HD 86728 indicate that the M dwarf (Gl 376B) is old, metal-rich and only 14.9 parsec away. The M dwarf is highly active, with both H α and X-ray emission. Thus, Gl 376B offers the opportunity to study an old, bright, active M dwarf with known metallicity, age and luminosity. We show that it is probable that Gl 376B is itself an unresolved pair. The other system consists of an M6.5 and an M8 dwarf with 14.5 arcsec separation. We estimate a distance of ∼16 parsec for this very low-mass pair. Stronger activity is observed in the M6.5 dwarf, supporting evidence that chromospheric activity is weakening near the hydrogen-burning limit.