Research on Purification Effect of Jian Lake Zizania latifolia Wetland Lakefront Zone in Northwest of Yunnan Plateau on Nitrogen and Phosphorus of Agricultural Non-point Source

As the main external pollution source of lake,nitrogen and phosphorus from agricultural non-point source make a great contribution to the lake eutrophication pollution.Wetland lakefront zone which plays a key role in externally agricultural non-point source pollution is considered as the biggest barrier for controlling external pollution.In this research,the Jian lake plateau Zizania latifolia wetland lakefront zone was selected for agricultural non-point source pollutions control with the systematic field research,and the lakefront zone was approved to have an effective purification effect on nitrogen and phosphorus from Jinlong River; the theoretical mechanism of lakefront zone removing nutrient was also investigated.Z.latifolia wetland lakefront zone could remove nitrogen and phosphorus from Jinlong River and the removal ratio can reach 55.8-62.52% and 59.47-69.81% respectively.So,we can indicate that the Jian Lake plateau Z.latifolia wetland lakefront zone had a good effect on controlling agricultural non-point source pollution and protecting the environment.

Measuring Tourist’s Water Footprint in a Mountain Destination of Northwest Yunnan, China

Monitoring and minimizing tourist’s water consumption is essential for the sustainable development of mountain destinations in the world. However, available data and a generally accepted protocol on such measurement are still limited. This study uses water footprint accounting to quantify tourist’s water demand in the Liming valley, a World Heritage site and a rapidly growing tourism destination in Northwest Yunnan, China. Both the water for direct and indirect use is taken into account based on the consumptive behavior of the tourists in the valley. Data were collected through guesthouse monitoring and a tourist survey in the 2005 tourist season. The results indicate that an average tourist leaves behind a footprint of 5.2 m3 on local water resources per day. Food production and waste dilution are the two most important water consumption factors. The results also show tourists consume more water than the local residents on per capita basis. This suggests more commitment is necessary to cope with this stress by individual tourists. Management implications to make water use more sustainable in mountain destinations are derived from this study.

Extraction of Mineral Alteration Zone from ETM+ Data in Northwestern Yunnan,China

Alteration is regarded as significant information for mineral exploration. In this study, ETM＋ remote sensing data are used for recognizing and extracting alteration zones in northwestern Yunnan （云南）, China. The principal component analysis （PCA） of ETM＋ bands 1, 4, 5, and 7 was employed for OH alteration extractions. The PCA of ETM＋ bands 1, 3, 4, and 5 was used for extracting Fe^2＋ （Fe^3＋） alterations. Interfering factors, such as vegetation, snow, and shadows, were masked. Alteration components were defined in the principal components （PCs） by the contributions of their diagnostic spectral bands. The zones of alteration identified from remote sensing were analyzed in detail along with geological surveys and field verification. The results show that the OH^- alteration is a main indicator of K-feldspar, phyllic, and prophilized alterations. These alterations are closely related to porphyry copper deposits. The Fe^2＋ （Fe^3＋） alteration indicates pyritization, which is mainly related to hydrothermal or skarn type polymetallic deposits.

The Principle and Method for Delineation of Potential Seismic Sources in Northwest Yunnan

Based on the collection and analysis of achievements of other scholars, and by consulting the results of seismic safety evaluation of engineering sites and field surveys of recent years, the seismotectonic indicators are determined for northwest Yunnan and its vicinity, and then potential seismic sources are further delineated. In practice, the following principles are applied: for areas with strong historical earthquakes, the recurrence principle is used to determine the upper bound magnitude; for areas with distinct seismogenic structure but no historical strong earthquake records, the tectonic analogy principle is used in the light of the size and activity behavior of the structure; for areas where the segmentation of the active fault is well studied, the potential sources will be demarcated more precisely; and for areas with buried fault, the seismicity pattern and geophysical abnormity are used to determine the direction of the major axis of the potential seismic source.

Geological Characteristics and Ore-controlling Factors of the Beiya Gold–Polymetallic Ore Deposit, Northwestern Yunnan Province

Based on comprehensive petrological, geochronological, and geochemical studies, this study analyzed the relationships between the Beiya gold-polymetallic skarn deposit and quartz syenite porphyries, and discussed the source（s） and evolution of magmas. Our results suggest that syenite porphyries（i.e. the Wandongshan, the Dashadi, and the Hongnitang porphyries）, which formed between the Eocene and the early Oligocene epochs, are the sources for the gold-polymetallic ores at the Beiya deposit. Carbonate rocks（T2 b） of the Triassic Beiya Formation in the ore district provide favorable host space for deposit formation. Fold and fault structures collectively play an important role in ore formation. The contact zone between the porphyries and carbonates, the structurally fractured zone of carbonate and clastic rocks, and the zone with well-developed fractures are the ideal locations for ore bodies. Four types of mineralization have been recognized： 1） porphyry-style stockwork gold–iron（copper） ore, 2） skarn-style gold-iron（copper and lead） ore in the near contact zone, 3） strata-bound, lense-type lead–silver–gold ore in the outer contact zone, and 4） distal vein-type gold–lead–silver ore. Supergene processes led to the formation of oxide ore, such as the weathered and accumulated gold–iron ore, the strata-bound fracture oxide ore, and the structure-controlled vein-type ore. Most of these ore deposits are distributed along the axis of the depressed basin, with the hypogene ore controlling the shape and characteristics of the oxide ore. This study provides critical geology understanding for mineral prospecting scenarios.

INTENSIFICATION OF TECTONIC MOVEMENT SINCE THE CENOZOIC AND ITS EFFECT ON GEOLOGICAL ENVIRONMENT IN NORTHWESTERN YUNNAN,CHINA

Since the Cenozoic,especially the Quaternary,tectonic movement has been strengthening in northwestern Yunnan,China.The tectonic elevation rate of mountains changed from 0.3～ 1.7 mm/a(before the Holocene)to 2～ 7.1 mm/a(after the Holocene).The subsiding velocity of the Holocene basins increases by 1～ 2 orders of magnitude relative to the Pleistocene.The displacement rate of the Quaternary fractures increases continuously.Modern crustal stress values become high.Tectonic deformation speeds up.Seismic activities strengthen.Geothermal flux anomaly is pronounced.The strengthening tectonic activities will result in changes of the topographic frame of northwestern Yunnan,worsen mountain geologic disaster,speed up the contraction of lakes and decrease the regional stability.Therefore,human beings will face the challenge of a more rigorous environment.

Research on Tectonic Features and Dynamics in the Northwestern Yunnan Extensional Region

The paper discusses the features of active tectonics,seismicity and neotectonic environment in the Northwestern Yunnan extensional region.The intensity of both tectonic activity and seismicity is strong near the south and north boundaries in the areas,but weak in the middle.The distribution of the strongest subsided areas,lacustrine terrace and Quaternary fold is characterized by the diagonal symmetry.Formation of extensional tectonics in the Northwestern Yunnan can be explained by passive model,experiencing the action of compressional force in the N-S direction and shear force in the SW-NE direction,and classified as a special pull-apart tectonics.The direction of the composite force is NNE,which is coincided with the results acquired by the methods of water-compressed rupture and physical modelling.

Study on the Influence of Environment Vulnerability in the Northwest Yunnan

With the deterioration of the global ecology,the eco-environment fragility has been an important topic of the ecological environment research.The Northwest Yunnan is a typical area of abundant biological resources and vulnerable ecological environment.The ecological environment vulnerability is more initiated by the human disturbances except its special natural basic factors such as the geological structure,the terrain,the geomorphology,the climate and hydrology conditions and so on.The paper analyses the human disturbances factors which impress the ecological environment vulnerability of the region from the negative interferences and positive interferences in order to enhance the research of the ecological environment to protect the ecological environment better in this area.

Stratigraphic Sequence and Tectonic Evolution of Passive Continental Margin of Jinshajiang Belt in Northwestern Yunnan, China

The Jinshajiang belt, located between the Zhongzan and Qamdo massifs, preserves varied sediments representing different tectonic background. Those sediments outcrop in stratigraphic slices,not in continuous stratigrapky. The stratigraphic slices of the passive continental margin are investigated by geologic mapping in Tuediug-Xiaruo, Northwestern Yunnan Province, and each of these slices is researched in age and sedimeutary environment. The stratigraphic successions of the passive continental margin are reconstructed. On the basis or new sequence, the evolutional history of the passive continental margin is divided into four stages: rift basin (D,-C,), complex continental margin basin (P1 ), residual hasin (P2-T2) and synorogenic basin (T3).

Magnetic Method Surveying and Its Application for the Concealed Ore-Bodies Prospecting of Laba Porphyry Molybdenum Ore Field in Shangri-La, Northwestern Yunnan Province, China

Recently, a number of large molybdenum (-copper) deposits have been discovered successively in the Laba area, Shangri-La county, northwestern Yunnan province. The investigation confirmed that there is a superlarge porphyry-skarn hydrothermal vein type molybdenum-polymetallic- metallogenic system with the total prediction reservoir of more than 150 mt molybdenum. The porphyry intrusions contributed to the mineralization closely, the superficial little vein molybdenum (-copper, lead, silver) ore-bodies are usually located in faults and fractures, and the deep porphyry type ore-bodies occurred in the granodiorite porphyries, the skarn type ore-bodies occurred in the contact zone intrused into Triassic limestone or Permian basalts. Laba ore block is a new exploration area with great prospecting potential. In order to reduce the target area and guide the further exploration work, the magnetic method measurement about 3.3 square kilometres was carried out in the ore field. This paper presents an application of analyzing the horizontal and vertical derivative, using Fast Fourier Transform (FFT) filter (FFT high-pass, low-pass, cosine roll-off, suscepbility), calculated spectra frequency energy to predict the depth and intensity of the apparent remanence magnetization of source (Hilbert). The calculated results and magnetic anomalous show that the remanence anomaly is caused by the intrusions into the Triassic limestone and Permian basalts with small anomalies, and the depth of located source is not great. We have identified a number of positions to the three drilled well, the drilled result specify interpretation with very high accuracy. The magnetic method is helpful to identify porphyry mineralization, and judge the shape and depth of the concealed ore-bearing intrusive bodies under the similar geological condition.

Palha Gedzong in Northwest Yunnan

The book Lost Horizon,written by British writer James Hilton,widely broadcasted the name of Shangri-la to the world.In his work,Shangri-la is not only a place enriched with snow-capped mountains,valleys,and splendid monasteries,but also one sprinkled with tranquilizing lakes surrounded by deep forests,sweet prairies.

THE LATE QUATERNARY RIGHT LATERAL STRIKE-SLIPPING OF ZHONGDIAN—DAJU FAULT IN NORTHWEST YUNNAN, CHINA

The Zhongdian—Daju fault is the transitional fault connecting the Kalakorum\|Jiali right lateral strike slip faulting zone and the Red River Fault, and a part of the south boundary of the eastward extrusive Tibet plateau. Field observations, associated with the analyses of the satellite images and air photographs, show that the Zhongdian—Daju fault, a 250km long fault in northwest Yunnan, is a nascent right lateral strike slip fault zone with the slip rate of 2～8mm/a. The Zhongdian—Daju fault is not a simple right lateral strike slip fault. There are several subparallel, slightly en échelon fault strands from Deqing to Yongsheng with the total length of 200km and perhaps 250km. Like the typical strike\|slip faults in this area, the morphological features of the fault, which can be seen clearly in the satellite images, are characterized as straight volleys and displaced gullies and ridges. In addition, Several Quaternary basins distribute along Zhongdian—Daju fault. The are controlled by the right lateral strike slipping of the fault in late Quaternary.

Alpine Ecosystems of Northwest Yunnan,China:an Initial Assessment for Conservation

Implementing conservation actions on-the-ground is not a straightforward process,especially when faced with high scientific uncertainty due to limited available information. This is especially acute in regions of the world that harbor many unique species that have not been well studied,such as the alpine zone of the Hengduan Mountains of Northwest Yunnan (NWY),a global biodiversity hotspot and site of The Nature Conservancy’s Yunnan Great Rivers Project. We conducted a quantitative,but rapid regional-level assessment of the alpine flora across NWY to provide a broad-based understanding of local and regional patterns of the alpine flora,the first large-scale analysis of alpine biodiversity patterns in this region. Multivariate analyses were used to classify the major plant community types and link community patterns to habitat variables. Our analysis indicated that most species had small distributions and/or small population sizes. Strong patterns emerged with higher diversity in the more northern mountains,but beta diversity was high,averaging only 10% among sites. The ordinations indicated that elevation and geographic location were the dominant environ-mental gradients underlying the differences in the species composition among communities. The high beta diversity across the alpine of these mountains implies that conservation strategies ultimately will require the protection of large numbers of species over a large geographical area. However,prioritiza-tion should be given to areas where potential payoffs are greatest. Sites with high species richness also have a greater number of endemic species,and,by focusing efforts on these sites,conservation investments would be maximized by protecting the greatest number of unique species.

THE CENOZOIC GEORECORDS IN THE NORTHWEST OF YUNNAN AND THE EVOLUTION OF QING—ZANG PLATEAU

The Cenozoic strata are well developed in the northwest of Yunnan Province, where the eastern boundary of Qing—Zang (Qinghai—Xizang) plateau is located. The rich geo\|records in the Cenozoic strata can help us to recapitulate the evolution history of Qing—Zang plateau.1\ The Cenozoic Strata Ninglang Formation (Paleocene—Middle Eocene) is composed of massively bedded conglomerate , mudstone in the lower part, purple thinly bedded—medium bedded fine quartz sandstone and sandy shale in the upper part, 600m thick. Lijiang Formation (Upper Eocene) and Jinsichang Formation (Oligocene): conglomerate, with a little sandstone in lower part, claystone, with a little conglomerate in the upper part. Lijiang Formation unconformably overlies on Ninglang Formation or even older strata, 1500～2000m thick. Shuanghe Formation (Miocene): thinly—massively bedded muddy siltstone, fine sandstone, marl, with several layers of coal. It unconformably overlies on Jinsichang Formation or even older strata, 108m thick. Sanying Formation (Pliocene): Claystone, siltstone, with a little lignite in the middle and upper part, conglomerate at the base, 110m thick, widely spread in the northwest of Yunnan.Sheshan Formation (early Pleistocene): pebbles, sands and clay layers. It unconformably overlies on the older strata, 100～187m thick.Heyunsi Formation (middle Pleistocene): poorly sorted and poorly rounded gravel and sands, 100～347m thick.Upper Pleistocene Series: glaciers—gravel, sands and clays; alluvial—sandy gravel layer(terraces); lacustrine—fine sand, silt and clay layer, 100 m thick.Holocene Series: lacustrine—sand, silt and clay layers; alluvial—sandy gravel layer (terraces), 50m thick.

Gravitational effect of water circulation in the northwest Yunnan

Water circulation is the main disturbance source against precise gravimetry measurement which is one of the principal means of geodynamic study. Some scientists studied the disturbance of water level changes in lakes andrivers and groundwater activities on gravity field.Taking water circulation as a whole and combining it with thehydrogeological conditions in northwest Yunnan mountainous area and the measured gravity data,this paperstudies the features, connections of water circulation in atmosphere,on surface and under ground and its effecton gravimetric data. The main conclusions are as follows: 1) The water circulation in atmosphere has little directdisturbance on gravity field 1 2 ) The change of lake water level may cause gravitational effect of (10- 20) × 10-8m. s-2 ; 3) In the NW Yunnan, types of the groundwater are various,and its changes are complicated, it isnecessary to study point by point. In general, its disturbance on gravity field in this region is about 10 × 10- 8m. s- 2, less than that in plain area.

Short-term Association of Meteorological Elements on COVID-19 Pandemic in a Semi-arid City of Northwest China,2021-2022

The coronavirus disease 2019(COVID-19)outbreak in late 2019 significantly impacted global health.The virus’s rapid spread,with its long incubation period and high infection level,caused substantial disruption to regular social frameworks,production,and lifestyles^([1]).COVID-19 is primarily transmitted through close contact,long-range contaminants,and airborne routes.

Climate and topography regulate the spatial pattern of soil salinization and its effects on shrub community structure in Northwest China

Soil salinization may affect biodiversity and species composition,leading to changes in the plant community structure.However,few studies have explored the spatial pattern of soil salinization and its effects on shrub community structure at the ecosystem scale.Therefore,we conducted a transect sampling of desert shrublands in Northwest China during the growing season(June–September)in 2021.Soil salinization(both the degree and type),shrub community structure(e.g.,shrub density and height),and biodiversity parameters(e.g.,Simpson diversity,Margalf abundance,Shannon-Wiener diversity,and Pielou evenness indices)were used to assess the effects of soil salinization on shrub community structure.The results showed that the primary degree of soil salinization in the study area was light salinization,with the area proportion of 69.8%.Whereas the main type of soil salinization was characterized as sulfate saline soil,also accounting for 69.8%of the total area.Notably,there was a significant reduction in the degree of soil salinization and a shift in the type of soil salinization from chloride saline soil to sulfate saline soil,with an increase in longitude.Regional mean annual precipitation(MAP),mean annual evapotranspiration(MAE),elevation,and slope significantly contributed to soil salinization and its geochemical differentiation.As soil salinization intensified,shrub community structure displayed increased diversity and evenness,as indicated by the increases in the Simpson diversity,Shannon-Wiener diversity,and Pielou evenness indices.Moreover,the succulent stems and leaves of Chenopodiaceae and Tamaricaceae exhibited clear advantages under these conditions.Furthermore,regional climate and topography,such as MAP,MAE,and elevation,had greater effects on the distribution of shrub plants than soil salinization.These results provide a reference for the origin and pattern of soil salinization in drylands and their effects on the community structure of halophyte shrub species.

Evaluating the Impact of the Universal Test and Treat Strategy on the Survival of Patients in the Northwest Region of Cameroon

Introduction: The main outcome of efficiently implemented universal test and treat (UTT) program is improved survival. UTT implementation has been ongoing in Cameroon since 2016 but evaluation data are scarce. This study aims to assess the survival of antiretroviral therapy (ART) patients initiated under UTT in Northwest region of Cameroon. Methods: This retrospective cohort study included HIV-positive patients initiated in 2016 at 27 purposefully selected sites and followed until 2021. Data was anonymously abstracted from ART registers and patients’ charts. Kaplan-Meier survival estimates and Cox model were used to compare the survival of patients initiated under UTT with those initiated otherwise, using stata version 14.0. Results: In total, 2490 HIV-positive patients (median age 42.7 years, 94.7% adults, and 69.0% female) participated in the study. Of 1389 patients with viral load (VL) test results, 55% were initiated on ART late. The VL suppression rate of patients initiated late and those initiated early were similar. During follow-up, 1020 (40.9%) participants censored. The survival curves of patients initiated early on ART and those initiated late were similar during the first 2.5 years of follow-up but significantly (p Conclusions: This study confirms the expected impact of UTT. Programs only need to close existing implementation gaps along the critical pathways (diagnosis and treatment) of UTT, focusing more on males.

Spatiotemporal variability of rain-on-snow events in the arid region of Northwest China

Rain-on-snow(ROS)events involve rainfall on snow surfaces,and the occurrence of ROS events can exacerbate water scarcity and ecosystem vulnerability in the arid region of Northwest China(ARNC).In this study,using daily snow depth data and daily meteorological data from 68 meteorological stations provided by the China Meteorological Administration National Meteorological Information Centre,we investigated the spatiotemporal variability of ROS events in the ARNC from 1978 to 2015 and examined the factors affecting these events and possible changes of future ROS events in the ARNC.The results showed that ROS events in the ARNC mainly occurred from October to May of the following year and were largely distributed in the Qilian Mountains,Tianshan Mountains,Ili River Valley,Tacheng Prefecture,and Altay Prefecture,with the Ili River Valley,Tacheng City,and Altay Mountains exhibiting the most occurrences.Based on the intensity of ROS events,the areas with the highest risk of flooding resulting from ROS events in the ARNC were the Tianshan Mountains,Ili River Valley,Tacheng City,and Altay Mountains.The number and intensity of ROS events in the ARNC largely increased from 1978 to 2015,mainly influenced by air temperature and the number of rainfall days.However,due to the snowpack abundance in areas experiencing frequent ROS events in the ARNC,snowpack changes exerted slight impact on ROS events,which is a temporary phenomenon.Furthermore,elevation imposed lesser impact on ROS events in the ARNC than other factors.In the ARNC,the start time of rainfall and the end time of snowpack gradually advanced from the spring of the current year to the winter of the previous year,while the end time of rainfall and the start time of snowpack gradually delayed from autumn to winter.This may lead to more ROS events in winter in the future.These results could provide a sound basis for managing water resources and mitigating related disasters caused by ROS events in the ARNC.

Ecological Network Resilience of Shiyang River Basin: An Arid Inland Watershed of Northwest China

Due to the uncertainties posed by climate change,resilience has become an increasingly important variable for evaluating regional ecosystem stability.The assessment of Ecological Network Resilience(ENR)is crucial for establishing mitigation strategies and sustainable socioeconomic development in arid regions.Shiyang River Basin is an arid watershed in Northwest China with complex characteristics,its ENR and spatial differentiation characteristics in 2020 were investigated in this work based on the Complex Adaptive System(CAS)theory.The results indicated that the mean Ecological Network Resilience Index(ENRI)value for the Shiyang River Basin was 0.390 in 2020,and the mean values in the southern mountainous,middle oasis,and northern desert regions of the basin were 0.598,0.461,and 0.237,respectively,demonstrating evident spatial differences.Additionally,the ENR of the basin exhibited distinct distribution characteristics across different dimension,whereas the trend of the integrated ENR of the basin was consistent with that of elemental,structural,and functional resilience,indicating the constructed three-region ENR model based on the logical relationship of element-structure-function was suitable for evaluation of the ENR in arid inland river watersheds.Furthermore,strategies for enhancing regional ENR were proposed from the perspective of adapting to climate change.