Potential recreation service efficiency of urban remnant mountain wilderness: A case study of Yunyan District of Guiyang city, China

As the precious resource of Karst mountainous city, urban remnant mountain wilderness (URMWs) can provide various of ecosystem services to the city. Taking the built-up area of the central urban area of Guiyang city center as the study area and the URMWs as the research object, an evaluation system of potential recreation service efficiency (PRSE) of URMWs was constructed through fuzzy Delphi method (F-Delphi), analytic hierarchy process (AHP) and entropy weight method (EWM), and PRSE of 69 URMWs in study area was evaluated and mapped. The recreation service characteristics of URMWs were analyzed from the perspective of supply and demand. Finally, the correlation of PRSE and the landscape features of URMWs was analyzed. Results showed that: (1) URMWs were mostly distributed in low and medium kernel density zones, and they had significant spatial agglomeration characteristics. (2) PRSE of URMWs was jointly affected by recreation potential, recreation opportunity and recreation demand. Among the 18 evaluation factors of PRSE evaluation system, the perfection of recreation service facilities, viewshed and green vision perception were the most important factors. In addition, PRSE of URMWs was significantly improved after park utilization. (3) PRSE of URMWs in the study area had significant spatial differences in suburban areas, which was higher in suburban areas than in urban centers and boundaries. The spatial mismatch between the supply and demand of recreation services was important reason for the low PRSE of URMWs. (4) PRSE of URMWs was significantly correlated with its three-dimensional features. The evaluation system constructed in this study could quantify PRSE of each URMW, reflect its spatial pattern, and provide a reference for the protection, development and utilization of URMWs in mountainous cities of Karst area

Multi-temporal evaluation and optimization of ecological network in multi-mountainous city

In karst multi-mountainous areas, there are a large number of urban remnant mountains (URMs) in urban built-up areas, which are an important part of urban green space system and have important and unique ecosystem service functions. However, the densifying development inside the city has been leading to the reduction of the number and area of the URMs and the decrease of the connectivity of the urban green space system, resulting in the fragile urban ecological environment. The construction and optimization of ecological network (EN) is an effective way to protect important urban ecological patches and improve the stability of urban green space ecosystem. Taking the central area of Anshun, a typical multi-mountainous city, as the study area, based on the land use data of 2007, 2012 and 2017, the ecological sources were identified by morphological spatial pattern analysis (MSPA) and the potential ecological corridors were extracted by the minimum cumulative resistance model (MCR), and the ENs of the three periods were identified. 18 ecological sources were selected for each of the three periods, with a total area of 833.67 hm2, 713.25 hm2 and 806.85 hm2, respectively and the intersection area of ecological sources reached 650.58 hm2. The ecological corridors and ecological sources dwindled with time. The Gravity model was used to extract the important EN corridor, the InVEST model was used to quantify the comprehensive habitat quality. The EN was optimized by adding extra ecological sources, mending ecological breakpoints and extracting habitat quality map patches. It is suggested to add 6 ecological sources and 34 ecological corridors, protect ecological nodes and build stepping stone patches. The results of this study could not only provide a scientific and reasonable basis for the ecological protection and the development of ecological protection strategies in the urban central area of Anshun, but also enrich the theoretical research of urban biodiversity conservation planning and ecological restoration practice in multi-mountainous cities

Vulnerability assessment of urban remnant mountain ecosystems based on ecological sensitivity and ecosystem services

Urban remnant mountains (URMs) are precious natural green habitat patches that can provide a series of ecosystem services for multi-mountainous cities. The increase in ecological sensitivity and degradation of ecosystem services affected by urban expansion and climate change have led to an increasing vulnerability of urban remnant mountain ecosystems (URMEs). To explore the vulnerability of URMEs, taking the central urban built-up area of the Guiyang city as the study area and URMs as the research object, the vulnerability of URMEs under natural factors and human disturbance was analyzed based on the Pressure-State-Response (PSR) model. The results showed that: (1) Karst rocky desertification, human disturbance, and road density within the buffer zones around URMs were the most important factors affecting the vulnerability of URMEs. Karst rocky desertification was the most likely eco-environmental problem of URMs, and carbon storage was the most important ecosystem service of URMEs. (2) Characteristics of fragile karst habitats in URMs and unreasonable human activities led to high ecological vulnerability, mainly with moderate and severe vulnerability predominating, and the low vulnerability of URMEs when they had moderate park utilization. (3) The ecological vulnerability of small URMs and those distributed in the urban center is higher, and the invulnerable URMEs and the slightly vulnerable URMEs are mainly distributed in the urban edge. The results of this study could provide references for ecological restoration and protection of URMs, and offer a basis for improving the resilience of multi-mountainous cities

Response of habitat quality to urban spatial morphological structure in multi-mountainous city

Revealing the relationship between urban spatial morphological structure (USMS) and habitat quality (HQ) is of great significance for high-quality urban development. In this study, the central urban area of a typical multi-mountainous city (Guiyang, China) was taken as research area. Two-dimensional (2D) and three-dimensional (3D) characteristic indicators system of USMS was constructed. The InVEST model was used to evaluate the HQ in the study area, and the spatial pattern characteristics of USMS and HQ in the multi-mountainous city were analyzed. Finally, the response relationship of HQ to USMS was revealed through Pearson correlation analysis and curve fitting. The results showed that: (1) The average level of HQ in the study area is low and the spatial aggregation effect is obvious; the spatial distribution difference between the high value area and the low value area is significant; the high value area is mainly distributed in the area where the large area of urban green space (UGS) and the urban remnant mountains (URMs) are located, while the low value area is mainly distributed in the high-intensity urban construction area. (2)The URMs have a significant impact on the USMS within the city, the intelligibility(I), spatial permeability, spatial aggregation degree, and spatial traffic attraction potential were poor; the buffer zone within 4 km of the urban center is the core area of urban development, and the buffer zone within 15 km is the rapid urban development area. (3)Among the USMS indicators, Choice(C) was significantly positively correlated with the HQ, while the Connectivity(Con), I, Average height(AVH), and Otherness(O) were significantly negatively correlated with the HQ. (4)Stepwise regression results showed that USMS could explain the difference of HQ in the study area well, and the values of fitting coefficient R2 were 0.975, 0.837 and 0.945 in 2008, 2013 and 2018, respectively. (5)There was a quadratic function relationship between HQ and USMS principal component factor f, and there was a threshold effect, and the thresholds were 0.798 in 2008, 0.905 in 2013 and 0.474 in 2018, respectively. This study confirmed the response relationship of HQ to USMS and demonstrates the existence of a threshold, which has important reference significance for urban biodiversity conservation and high-quality urban development

Crustal thickening in Gansu-Qinghai, lithospheric mantle subduction, and oblique, strike-slip controlled growth of the Tibet plateau

International audienceFieldwork complemented by SPOT image analysis throws light on current crustal shortening processes in the ranges of northeastern Tibet (Gansu and Qinghai provinces, China). The ongoing deformation of Late-Pleistocene bajada aprons in the forelands of the ranges involves folding, at various scales, and chiefly north-vergent, seismogenic thrusts. The most active thrusts usually break the ground many kilometres north of the range-fronts, along the northeast limbs of growing, asymmetric ramp-anticlines. Normal faulting at the apex of other growing anticlines, between the range fronts and the thrust breaks, implies slip on blind ramps connecting distinct active décollement levels that deepen southwards. The various patterns of uplift of the bajada surfaces can be used to constrain plausible links between contemporary thrusts downsection. Typically, the foreland thrusts and décollements appear to splay from master thrusts that plunge at least 15–20 km down beneath the high ranges. Plio-Quaternary anticlinal ridges rising to more than 3000 m a.s.l. expose Palaeozoic metamorphic basement in their core. In general, the geology and topography of the ranges and forelands imply that structural reliefs of the order of 5–10 km have accrued at rates of 1–2 mm yr−1 in approximately the last 5 Ma. From hill to range size, the elongated reliefs that result from such Late-Cenozoic, NE–SW shortening appear to follow a simple scaling law, with roughly constant length/width ratio, suggesting that they have grown self-similarly. The greatest mountain ranges, which are over 5.5 km high, tens of kilometres wide and hundreds of kilometres long may thus be interpreted to have formed as NW-trending ramp anticlines, at the scale of the middle–upper crust. The fairly regular, large-scale arrangement of those ranges, with parallel crests separated by piggy-back basins, the coevality of many parallel, south-dipping thrusts, and a change in the scaling ratio (from #5 to 8) for range widths greater than #30 km further suggests that they developed as a result of the northeastward migration of large thrust ramps above a broad décollement dipping SW at a shallow angle in the middle–lower crust. This, in turn, suggests that the 400–500 km-wide crustal wedge that forms the northeastern edge of the Tibet–Qinghai plateau shortens and thickens as a thickskinned accretionary prism decoupled from the stronger upper mantle underneath. Such a thickening process must have been coupled with propagation of the Altyn Tagh fault towards the ENE because most thrust traces merge northwestwards with active branches of this fault, after veering clockwise. This process appears to typify the manner in which the Tibet–Qinghai highlands have expanded their surface area in the Neogene. The present topography and structure imply that, during much of that period,

Enhancement Mode Ga2O3 Field Effect Transistor with Local Thinning Channel Layer

β−Ga2O3 field−effect transistors (FETs) were fabricated with and without local thinning to change the threshold voltage. A 220 nm Ga2O3 layer was mechanically exfoliated from a Cr−doped gallium oxide single crystal. Approximately 45 nm Ga2O3 was etched by inductively coupled plasma to form the local thinning. The threshold voltage of the device with etched local thinning increased from −3 V to +7 V compared to the unetched device. The effect of the local thinning was analyzed by device simulation, confirming that the local thinning structure is an effective method to enable enhancement−mode Ga2O3 FETs

High-efficiency broadband (> 210 nm) in-band pumped Tm:LuGGG solid-state laser

Funding Information: This work was supported by the National Natural Science Foundation of China (62175133), the Natural Science Foundation of Shandong Province (ZR2020MF115), and the SDUST Research Fund (skr21-3-049, 2019TDJH103). Publisher Copyright: © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Here, we demonstrate a broadband tunable (Lu0.0541Tm0.0548Gd0.8911)3Ga3O12 (Tm:LuGGG) laser in-band pumped by a homemade 1645-nm Er:YAG laser. A maximum average output power of 0.7 W at 1997 nm is obtained with a slope efficiency of 46.3%. We also demonstrate a continuously tuning output ranging from1854 to 2066 nm with a tuning coverage of 212 nm. The results indicate that the Tm:LuGGG crystal is an excellent laser medium for high-efficient broadband light generation, which may help to explore potential applications in ultrafast lasers.Peer reviewe

Chinese mothers’ intention to vaccinate daughters against human papillomavirus (HPV), and their vaccine preferences: a study in Fujian Province

Little is known regarding Chinese mothers’ intention to vaccinate their daughters against human papillomavirus (HPV) since the HPV vaccine was approved for use in China in 2016. The aim was to explore maternal HPV vaccination acceptance, preference for 2-, 4- or 9-valent HPV vaccine and acceptance of domestically manufactured HPV vaccines. Study participants were mothers of primary school children in Southeastern region of Fujian. An online cross-sectional survey was undertaken between June and August 2019. Among the total of 3,586 completed responses (response rate 28.5%), the intention to vaccinate daughter against HPV was high (83.3%). Higher maternal education and perceived benefit and barriers were associated with greater intention to vaccinate. Among mothers who did not intend to vaccinate their daughters, the three most common reasons were daughter being too young to receive HPV vaccination (40.6%), fear of side effects (31.9%) and vaccine price is too high (16.0%). The largest proportion (41.4%) preferred their daughter to be vaccinated with the 9-valent HPV vaccine (9vHPV). Greater preference for 9vHPVwas strongly associated with higher maternal education level and annual household income. The majority of mothers expressed a preference for imported HPV vaccine (56.3%). Our result indicates that lower intentions to vaccinate daughters against HPV among less educated and lower-income mothers may lead to significant social inequalities in HPV vaccine uptake in the country