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1. chinaXiv:202112.00013 [pdf]

A new method of searching for concealed Au deposits by using the spectrum of arid desert plant species

CUI Shichao; ZHOU Kefa; ZHANG Guanbin; DING Rufu; WANG Jinlin; CHENG Yinyi; JIANG Guo
Subjects: Geosciences >> Geography

With the increase of exploration depth, it is more and more difficult to find Au deposits. Due to the limitation of time and cost, traditional geological exploration methods are becoming increasingly difficult to be effectively applied. Thus, new methods and ideas are urgently needed. This study assessed the feasibility and effectiveness of using hyperspectral technology to prospect for hidden Au deposits. For this purpose, 48 plant (Seriphidium terrae-albae) and soil (aeolian gravel desert soil) samples were first collected along a sampling line that traverses an Au mineralization alteration zone (Aketasi mining region in an arid region of China) and were used to obtain soil Au contents by a chemical analysis method and the reflectance spectra of plants obtained with an Analytical Spectral Device (ASD) FieldSpec3 spectrometer. Then, the corresponding relationship between the soil Au content anomaly and concealed Au deposits was investigated. Additionally, the characteristic bands were selected from plant spectra using four different methods, namely, genetic algorithm (GA), stepwise regression analysis (STE), competitive adaptive reweighted sampling (CARS), and correlation coefficient method (CC), and were then input into the partial least squares (PLS) method to construct a model for estimating the soil Au content. Finally, the quantitative relationship between the soil Au content and the 15 different plant transformation spectra was established using the PLS method. The results were compared with those of a model based on the full spectrum. The results obtained in this study indicate that the location of concealed Au deposits can be predicted based on soil geochemical anomaly information, and it is feasible and effective to use the full plant spectrum and PLS method to estimate the Au content in the soil. The cross-validated coefficient of determination (R2) and the ratio of the performance to deviation (RPD) between the predicted value and the measured value reached the maximum of 0.8218 and 2.37, respectively, with a minimum value of 6.56 μg/kg for the root-mean-squared error (RMSE) in the full spectrum model. However, in the process of modeling, it is crucial to select the appropriate transformation spectrum as the input parameter for the PLS method. Compared with the GA, STE, and CC methods, CARS was the superior characteristic band screening method based on the accuracy and complexity of the model. When modeling with characteristic bands, the highest accuracy, R2 of 0.8016, RMSE of 7.07 μg/kg, and RPD of 2.20 were obtained when 56 characteristic bands were selected from the transformed spectra (1/lnR)' (where it represents the first derivative of the reciprocal of the logarithmic spectrum) of sampled plants using the CARS method and were input into the PLS method to construct an inversion model of the Au content in the soil. Thus, characteristic bands can replace the full spectrum when constructing a model for estimating the soil Au content. Finally, this study proposes a method of using plant spectra to find concealed Au deposits, which may have promising application prospects because of its simplicity and rapidity.

submitted time 2021-12-03 From cooperative journals:《Journal of Arid Land》 Hits15Downloads8 Comment 0

2. chinaXiv:202112.00014 [pdf]

Elevated CO2 increases shoot growth but not root growth and C:N:P stoichiometry of Suaeda aralocaspica plants

WANG Lei; FAN Lianlian; JIANG Li; TIAN Changyan
Subjects: Geosciences >> Geography

The purpose of the current study was to investigate the eco-physiological responses, in terms of growth and C:N:P stoichiometry of plants cultured from dimorphic seeds of a single-cell C4 annual Suaeda aralocaspica (Bunge) Freitag and Schütze under elevated CO2. A climatic chamber experiment was conducted to examine the effects of ambient (720 μg/L) and CO2-enriched (1440 μg/L) treatments on these responses in S. aralocaspica at vegetative and reproductive stages in 2012. Result showed that elevated CO2 significantly increased shoot dry weight, but decreased N:P ratio at both growth stages. Plants grown from dimorphic seeds did not exhibit significant differences in growth and C:N:P stoichiometric characteristics. The transition from vegetation to reproductive stage significantly increased shoot:root ratio, N and P contents, but decreased C:N, C:P and N:P ratios, and did not affect shoot dry weight. Moreover, our results indicate that the changes in N:P and C:N ratios between ambient and elevated CO2 are mainly caused by the decrease of N content under elevated CO2. These results provide an insight into nutritional metabolism of single-cell C4 plants under climate change.

submitted time 2021-12-03 From cooperative journals:《Journal of Arid Land》 Hits25Downloads17 Comment 0

3. chinaXiv:202112.00016 [pdf]

Temporal and spatial variations of net primary productivity and its response to groundwater of a typical oasis in the Tarim Basin, China

SUN Lingxiao; YU Yang; GAO Yuting; ZHANG Haiyan; YU Xiang; HE Jing; WANG Dagang; Ireneusz MALIK; Malgorzata WISTUBA; YU Ruide
Subjects: Geosciences >> Geography

Net primary productivity (NPP) of the vegetation in an oasis can reflect the productivity capacity of a plant community under natural environmental conditions. Owing to the extreme arid climate conditions and scarce precipitation in the arid oasis regions, groundwater plays a key role in restricting the development of the vegetation. The Qira Oasis is located on the southern margin of the Taklimakan Desert (Tarim Basin, China) that is one of the most vulnerable regions regarding vegetation growth and water scarcity in the world. Based on remote sensing images of the Qira Oasis and daily meteorological data measured by the ground stations during the period 2006–2019, this study analyzed the temporal and spatial patterns of NPP in the oasis as well as its relation with the variation of groundwater depth using a modified Carnegie Ames Stanford Approach (CASA) model. At the spatial scale, NPP of the vegetation decreased from the interior of the Qira Oasis to the margin; at the temporal scale, NPP of the vegetation in the oasis fluctuated significantly (ranging from 29.80 to 50.07 g C/(m2?month)) but generally showed an increasing trend, with the average increase rate of 0.07 g C/(m2?month). The regions with decreasing NPP occupied 64% of the total area of the oasis. During the study period, NPP of both farmland and grassland showed an increasing trend, while that of forest showed a decreasing trend. The depth of groundwater was deep in the south of the oasis and shallow in the north, showing a gradual increasing trend from south to north. Groundwater, as one of the key factors in the surface change and evolution of the arid oasis, determines the succession direction of the vegetation in the Qira Oasis. With the increase of groundwater depth, grassland coverage and vegetation NPP decreased. During the period 2008–2015, with the recovery of groundwater level, NPP values of all types of vegetation with different coverages increased. This study will provide a scientific basis for the rational utilization and sustainable management of groundwater resources in the oasis.

submitted time 2021-12-03 From cooperative journals:《Journal of Arid Land》 Hits21Downloads13 Comment 0

4. chinaXiv:202112.00015 [pdf]

Using statistical models and GIS to delimit the groundwater recharge potential areas and to estimate the infiltration rate: A case study of Nadhour-Sisseb-El Alem Basin, Tunisia

Subjects: Geosciences >> Geography

The water resources of the Nadhour-Sisseb-El Alem Basin in Tunisia exhibit semi-arid and arid climatic conditions. This induces an excessive pumping of groundwater, which creates drops in water level ranging about 1–2 m/a. Indeed, these unfavorable conditions require interventions to rationalize integrated management in decision making. The aim of this study is to determine a water recharge index (WRI), delineate the potential groundwater recharge area and estimate the potential groundwater recharge rate based on the integration of statistical models resulted from remote sensing imagery, GIS digital data (e.g., lithology, soil, runoff), measured artificial recharge data, fuzzy set theory and multi-criteria decision making (MCDM) using the analytical hierarchy process (AHP). Eight factors affecting potential groundwater recharge were determined, namely lithology, soil, slope, topography, land cover/use, runoff, drainage and lineaments. The WRI is between 1.2 and 3.1, which is classified into five classes as poor, weak, moderate, good and very good sites of potential groundwater recharge area. The very good and good classes occupied respectively 27% and 44% of the study area. The potential groundwater recharge rate was 43% of total precipitation. According to the results of the study, river beds are favorable sites for groundwater recharge.

submitted time 2021-12-03 From cooperative journals:《Journal of Arid Land》 Hits19Downloads12 Comment 0

5. chinaXiv:202112.00017 [pdf]

Predicting of dust storm source by combining remote sensing, statistic-based predictive models and game theory in the Sistan watershed, southwestern Asia

Subjects: Geosciences >> Geography

Dust storms in arid and desert areas affect radiation budget, air quality, visibility, enzymatic activities, agricultural products and human health. Due to increased drought and land use changes in recent years, the frequency of dust storms occurrence in Iran has been increased. This study aims to identify dust source areas in the Sistan watershed (Iran-Afghanistan borders)–an important regional source for dust storms in southwestern Asia, using remote sensing (RS) and bivariate statistical models. Furthermore, this study determines the relative importance of factors controlling dust emissions using frequency ratio (FR) and weights of evidence (WOE) models and interpretability of predictive models using game theory. For this purpose, we identified 211 dust sources in the study area and generated a dust source distribution map–inventory map–by dust source potential index based on RS data. In addition, spatial maps of topographic factors affecting dust source areas including soil, lithology, slope, Normalized difference vegetation index (NDVI), geomorphology and land use were prepared. The performance of two models (WOE and FR) was evaluated using the area under curve (AUC) of the receiver operating characteristic curve. The results showed that soil, geomorphology and slope exhibited the greatest influence in the dust source areas. The 55.3% (according to FR) and 62.6% (according to WOE) of the total area were classified as high and very high potential dust sources, while both models displayed acceptable accuracy with subsurface levels of 0.704 for FR and 0.751 for WOE, although they predict different fractions of dust potential classes. Based on Shapley additive explanations (SHAP), three factors, i.e., soil, slope and NDVI have the highest impact on the model's output. Overall, combination of statistic-based predictive models (or data mining models), RS and game theory techniques can provide accurate maps of dust source areas in arid and semi-arid regions, which can be helpful for mitigation of negative effects of dust storms.

submitted time 2021-12-03 From cooperative journals:《Journal of Arid Land》 Hits18Downloads11 Comment 0

6. chinaXiv:202112.00018 [pdf]

A bibliometric analysis of carbon exchange in global drylands

LIU Zhaogang; CHEN Zhi; YU Guirui; ZHANG Tianyou; YANG Meng
Subjects: Geosciences >> Geography

Drylands refer to regions with an aridity index lower than 0.65, and billions of people depend on services provided by the critically important ecosystems in these areas. How ecosystem carbon exchange in global drylands (CED) occurs and how climate change affects CED are critical to the global carbon cycle. Here, we performed a comprehensive bibliometric study on the fields of annual publications, marked journals, marked institutions, marked countries, popular keywords, and their temporal evolution to understand the temporal trends of CED research over the past 30 a (1991–2020). We found that the annual scientific publications on CED research increased significantly at an average growth rate of 7.93%. Agricultural Water Management ranked first among all journals and had the most citations. The ten most productive institutions were centered on drylands in America, China, and Australia that had the largest number and most citations of publications on CED research. "Climate change" and climate-related (such as "drought", "precipitation", "temperature", and "rainfall") research were found to be the most popular study areas. Keywords were classified into five clusters, indicating the five main research focuses on CED studies: hydrological cycle, effects of climate change, carbon and water balance, productivity, and carbon-nitrogen-phosphorous coupling cycles. The temporal evolution of keywords further showed that the areas of focus on CED studies were transformed from classical pedology and agricultural research to applied ecology and then to global change ecological research over the past 30 a. In future CED studies, basic themes (such as "water", "yield", and "salinity") and motor themes (such as "climate change", "sustainability", and "remote sensing") will be the focus of research on CED. In particular, multiple integrated methods to understand climate change and ecosystem sustainability are potential new research trends and hotspots.

submitted time 2021-12-03 From cooperative journals:《Journal of Arid Land》 Hits21Downloads14 Comment 0

7. chinaXiv:202112.00012 [pdf]


方慧; 付辉建; 张慧君
Subjects: Psychology >> Management Psychology


submitted time 2021-12-03 Hits77Downloads42 Comment 0

8. chinaXiv:202104.00088 [pdf]


金茜茜; 陈虹枢; 黄晓兰
Subjects: Library Science,Information Science >> Philology

目的/意义 面对世界范围内各种思想文化交流、交融、交锋的新形势,深入挖掘国际传媒研究热点,对促进我国传媒领域的学术发展与学科体系完善具有重要意义。 方法/过程 本文以Web of Science数据库中2015年至2019年传媒类期刊文献数据为基础,结合概率主题模型、文献计量方法以及自然语言处理技术对文档内容和元数据进行联合建模,构建国家-主题分布矩阵,较为全面地挖掘了近五年来国际传媒研究的地理分布与知识结构,最终落脚于国内传媒领域研究的热点主题分析。 结果/结论 研究结果表明,数字技术推动新媒体蓬勃发展,不断刺激传媒领域的产业升级与文化重塑。我国部分主题在理论研究、产学交流、学科融合等方面仍存在探索与提升的空间,需要在重视理论研究与应用研究、基础学科与新兴学科协同发展的基础上,开展符合国内需求、具有国际视野的传媒研究,为传媒领域的持续深入发展添砖加瓦。

submitted time 2021-12-02 Hits15623Downloads688 Comment 0

9. chinaXiv:202112.00019 [pdf]

Syn-subduction intra-continental shearing during Oligocene in Indochina, SE Asia

Zhang, Ji'en; Xiao, Wenjiao; Zhang, Bo; Wakabayashi, John; Cai, Fulong; Sein, Kyaing
Subjects: Geosciences >> Geology

Indochina developed continental-scale shear zones that record Cenozoic tectonic processes in SE Asia. Previous extrusion models that linked these shear zones with the northward indentation of the Indian continent, conflict with distributed conjugate strike-slip pairs and post-Oligocene rotation in Indochina. This paper presents evidence of coeval shearing along the Mogok-Shan Scarp fault in Myanmar, the western boundary of the Indochina block, previously proposed as a product of northward indentation of Indian Plate. The Kyanigan quarry along the northern Mogok-Shan Scarp fault exposes paragneiss, marble and quartzite schist. ‘σ’ structures, cored with garnet, in paragneiss record right-lateral shear sense, consistent with ‘σ’ and ’δ’ structures in L-tectonites in the Moulmein granitic mylonite to the south. U-Pb ages of metamorphic zircons of paragneiss and a biotite 39Ar-40Ar age of quartzite schist constrain deformation in the Kyanigan quarry to 33-21 Ma; a biotite 39Ar-40Ar age of mylonite at Moulmein is 26 Ma. These ages demonstrate Oligocene right-lateral shearing along the Mogok-Shan Scarp fault, coeval with other shear zones in Indochina. These Oligocene shear zones and strike-slip faults are conjugate structures recording left-lateral shear sense on NW-striking and right-lateral shear sense on N-S to NE-striking features. After restoration of ~80° clockwise rotation, the Oligocene conjugate strike-slip pairs in Indochina reflect approximate N-S-directed shortening, corresponding to northward subduction of the Indian ocean. This suggests that continental-scale intra-continental shearing may have been triggered by syn-subduction compression in SE Asia.

submitted time 2021-12-01 Hits22Downloads13 Comment 0

10. chinaXiv:202112.00007 [pdf]

AOM DSS诱导炎症引起的小鼠结直肠癌模型尿液蛋白质组的研究

衡姊琦; 高友鹤
Subjects: Biology >> Biochemistry

摘要: [目的]尿液蛋白质组能够灵敏的反映机体的生理变化,可以为炎症引起的结直肠癌的发展提供一定线索。 [方法]本研究使用液相色谱联用质谱(LC-MS/MS),对利用AOM/DSS诱导炎症引起的结直肠癌小鼠模型的尿液差异蛋白进行筛选并进行生物学通路的分析,从生物学通路层面去寻找规律,探究小鼠炎癌模型在结直肠癌的发展中的变化过程。 [结果](1)尿液蛋白质组的变化能够反映实验小鼠的病理生理变化。所有实验小鼠差异蛋白富集到被报道过的且与炎症和肿瘤相关的共有生物学通路有:急性期反应、细胞黏附、天然免疫反应、蛋白激酶B信号的正调控、B细胞活化正调控、糖代谢的相关通路,特别是免疫相关的反应伴随始终。(2)实验小鼠的疾病进展不同,进展不同阶段的小鼠尿液蛋白质组表现不同。本研究运用的单只小鼠独立分析的研究方法能为炎癌模型的小鼠疾病进程提供线索,同时也为未来个性化、精准化疾病分析的方法提供借鉴。

submitted time 2021-12-01 Hits123Downloads50 Comment 0

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