Surface pollen in the east of Qaidam Basin

Pollen analysis of 23 surface samples in the east of Qaidam Basin reveals the characteristics of pollen assemblages and their relationships with vegetation and climate. In pollen assemblages, Chenopodiaceae and Artemisia are preponderant types in all the samples, and Ephedra, Gramineae and Compositae are common types. The results of DCA （Detrended Correspondance Analysis） and Correlation Analysis show different pollen assemblages indicate different vegetations, coincided with respective vegetation types. A/C （Artemisia/Chenopodiaceae） in the desert can indicate the aridity. Depending on the aridity, the vegetation communities are divided into four groups： severe drought group, moderate drought group, slight drought group and tropophilous group. A/C value is less 0.2 in the severe drought group, 0.2-0.5 in the moderate drought group, 1.63 in the slight drought group and 5.72 slight-wetness group.

Correlation between HbA1c and Extent of Mucormycosis Disease—A Prospective Observative Study

Background: Prognosis in Mucormycosis is poor, secondary to the nature of such opportunistic angioinvasive fungal infection that affects immuno-compromised patients with uncontrolled diabetes which is a common risk factors in most of the cases. Objectives: Patients with post-Covid Mucormycosis presenting to the ENT OPD were included and evaluated for HbA1c, extent of disease, and subsequently underwent the required modality of management. Methods: A prospective observational study was done in 154 patients of mucormycosis and according to the extent of disease such as sinonasal involvement, orbital extension or intracranial extension, the HbA1c values were compared among themselves. Results: In our study, out of 154 patients, 86 (55.8%) patients have only sinonasal involvement, 30 (19.4%) patients have extension into orbit and 38 (24.6%) patients have intracranial spread. In patients with sinonasal involvement, mean HbA1c was 9.8 ± 2.41;in orbital extension, mean HbA1c was 12.7 ± 2.31 and in intracranial extension, mean HbA1c was 13.4 ± 1.98. Conclusion: In our study, elevated HbA1c is indicative of poor glycaemic control and positively correlated with increased invasiveness and aggressive fungal disease.

基于质子串分解的中文术语自动抽取

针对中文术语构成特点,提出了一种基于质子串分解的术语自动抽取方法,将词分为2类:结构简单的质词和有复杂结构的合词;使用参数F-MI抽取结构简单的质词;并在其基础上,进一步使用质子串分解方法抽取具有复杂结构的合词。实验结果显示,该算法有效地提高了中文自动术语抽取的精确度。目前该算法已在国家网络媒体监测项目中得到了应用,并显示了良好的效果。

C-value值和unithood指标结合的中文科技术语抽取

研究从科技论文文本中抽取作者关键词以外的科技术语的方法。因为标引效应问题,单纯选择论文中的关键词作为候选术语会影响术语库的数量和质量,需要考虑从论文文本中抽取术语。现有的大多数术语抽取方法重视采用termhood指标,而忽视unithood指标,针对此问题,在C-value算法的基础上,提出用于生成候选术语的中文术语构词规则和测量术语内部结合强度的unithood指标,实现从论文文本中抽取中文科技术语。以信息资源管理领域的术语抽取为例对提出的方法进行验证,实验结果证明,提出的方法能够有效地抽取领域科技术语,抽取精度较高。

一种基于改进似然比的术语自动抽取方法

术语自动抽取是信息处理领域的基础性课题,日益受到研究者的关注。似然比方法能有效抽取低频词汇,但抽取准确率偏低。为了解决这个问题,将似然比的抽取结果用C-value进行改进。实验证明,两者相结合,在保证似然比方法高召回率的前提下,比单纯依靠似然比方法抽取准确率提高了约8%。

Estimating Change in Sedimentary Organic Carbon Content During Mangrove Restoration in Southern China Using Carbon Isotopic Measurements

Based on total carbon(C) and C isotopes in sediment cores,sedimentary organic carbon(SOC) was quantified in three types of mangrove sites(barren flat sites without mangroves,mangrove plantations,and natural mangrove forests),which were considered to represent a continuum from least restored to most restored sites in southern China.SOC densities in the barren sites,plantations,and natural forests were 90,170 and 288 Mg ha 1,respectively.We inferred that mangrove restoration increased SOC accumulation in coastal areas.At 0-70 cm depth,SOC δ 13 C values in both mangrove sites ranged from 27.37‰ to 23.07‰ and exhibited gradual enrichment with depth.In contrast,the values in the barren flat sites remained around 22.19‰ and fluctuated slightly with depth.At 0-60 cm,the 14 C ages of the SOC in the barren flat site,the natural mangrove site,and the artificial mangrove site ranged from 1 397 to 2 608,255 to 2 453,and 391 to 2 512 years BP,respectively.In both types of mangrove sites but not in the barren flat sites,the enrichment of δ 13 C with depth was related to increases in SOC decay and SOC age with depth.According to analysis of 14 C age,much of the mangrove-derived C was transported and stored at 0-60 cm depth under anaerobic conditions in both mangrove sites.The sediments of mangrove forests in southern China sequester large quantities of SOC during mangrove restoration.

The distribution characteristic and its significance of compound specific isotopic composition of aromatic hydrocarbon from marine source rock and oil in the Tarim Basin, western China

Aromatic hydrocarbons are generally main distillation of crude oil and organic extract of source rocks. Bicyclic and tricyclic aromatic hydrocarbons can be purified by two-step method of chromatography on alumina. Carbon isotopic composition of in- dividual aromatic hydrocarbons is affected not only by thermal maturity, but also by organic matter input, depositional envi- ronment, and hydrocarbon generation process based on the GC-IRMS analysis of Upper Ordovician, Lower Ordovician, and Cambrian source rocks in different areas in the Tarim Basin, western China. The subgroups of aromatic hydrocarbons as well as individual aromatic compound, such as 1-MP, 9-MP, and 2,6-DMP from Cambrian-Lower Ordovician section show more depleted 13C distribution. The δ13C value difference between Cambrian-Lower Ordovician section and Upper Ordovician source rocks is up to 16.1%o for subgroups and 14%o for individual compounds. It can provide strong evidence for oil source correlation by combing the δ13C value and biomarker distribution of different oil and source rocks from different strata in the Tarim Basin. Most oils from Tazhong area have geochemical characteristics such as more negative δI3Cg_Mp value, poor gam macerane, and abundant homohopanes, which indicate that Upper Ordovician source rock is the main source rock. In contrast, oils from Tadong area and some oils from Tazhong area have geochemical characteristics such as high 613C9-MP, value, abun dant gammacerane, and poor homohopanes, which suggest that the major contributor is Cambrian-Lower Ordovician source rock.

Catchment environmental change over the 20th Century recorded by sedimentary leaf wax n-alkane δ^(13)C off the Pearl River estuary

The compound-specific stable carbon isotope compositions(δ^(13)C) of leaf wax n-alkanes from two short sediment cores recovered off the Pearl River estuary(PRE) were analyzed to check for their capability of indicating decadal scale catchment environmental change. Sedimentary long-chain n-alkanes exhibited an odd-over-even predominance, with a maximum at n-C_(29) or n-C_(31), indicating their leaf wax origin was from vascular plants. The δ^(13)C values of C_(29) and C_(31) n-alkane in all the sediment samples were in the range of -28.8‰ to -31.2‰, consistent with the C_3 plant-dominated vegetation in the Pearl River catchments. The time series of δ^(13)C records from the two cores were comparable and displayed a decreasing trend from the early 20 th century to the end of the 1970s, followed by a reversal in that change leading to continued increase for ca. 15 years. After being corrected for the effect of atmospheric CO_2 rise and δ^(13)C_(atm) decline, the δ^(13)C_(29) records largely retained their raw changing pattern; the post-1980 increase being more conspicuous. The slightly decreasing trend in corrected δ^(13)C records before around 1980 may have been caused by an increase in precipitation, whereas the subsequent increase of δ^(13)C is likely associated with the observed dry climate and/or intensive anthropogenic deforestation. Our results thus demonstrate that leaf wax n-alkanes buried in the sediments off the PRE may well reflect change in the regional climate and/or human activity in the river catchments over the past century.

8,4′-Oxyneolignane glucosides from an aqueous extract of“ban lan gen”(Isatis indigotica root)and their absolute configurations

Three pairs of glycosidic 8,4′-oxyneolignane diastereoisomers, named isatioxyneolignosides A-F(1–6), were isolated from an aqueous extract of Isatis indigotica roots. Their structures and absolute configurations were elucidated by comprehensive spectroscopic data analysis and enzyme hydrolysis. The validity of Δδ_(C8-C7) values to distinguish threo and erythro aryl glycerol units and Cotton effects at 235±5 nm to determine absolute configurations at C-8 in 1–6 and their aglycones(1a–6a) are discussed.

政务领域本体术语的自动抽取

提出一种新的政务本体术语自动抽取的方法。首先通过中文分词技术和单字合并法提取政务文本中的词作为候选术语;通过C-value求解法和TF-IDF算法对候选术语进行过滤抽取,从而实现政务领域术语的自动抽取。通过实验比较,发现该方法在不影响领域术语抽取召回率的同时可以提高抽取术语的正确率。