Photosynthetic characteristics and reproductive strategies of Polygonum viviparum at different altitudes in the Qilian Mountains北大核心CSCD

Polygonum viviparum, which reproduces sexually and asexually, is widely distributed in the Qinghai-Tibet Plateau, and its reproduction strategies are very sensitive to changes in the environment. This study aimed to elucidate the effect of altitude on the photosynthetic characteristics and reproductive strategies of P. viviparum. This study was conducted to investigate the responses of photosynthetic, vegetative, and reproductive traits of P. viviparum populations along six altitudinal gradients in the eastern part of the Qilian Mountains in China. Our results indicated that, with increasing altitude, the net photosynthetic rate of P. viviparum showed an increasing trend, reaching its maximum value (14.39 μmol m–2 s–1) at 3 700 m above sea level. The transpiration rate showed an increasing trend, followed by a decreasing trend, and the intercellular CO2 concentration did not differ significantly between altitudes. With increasing altitude, the plant height and leaf area of P. viviparum showed a downward trend, the aboveground and underground biomass decreased, and the specific leaf area initially decreased and then increased. However, the leaf greenness index showed an upward trend, and the number of stomata in the upper and lower epidermis of leaves initially increased and then decreased. With increasing altitude, the proportion of inflorescence length per plant (the ratio of inflorescence length to plant height), the proportion of bulbil length per inflorescence (the ratio of bulbil length to inflorescence height), and the proportion of the number of bulbils per inflorescence (the ratio of the number of bulbils to the total number of flowers and bulbils) showed an increasing trend. Air temperature and light intensity are the major environmental factors affecting the photosynthetic characteristics and functional traits of P. viviparum. Thus, P. viviparum is exposed to more environmental stresses and obtains less energy when altitude increases, but it adapts to the harsh alpine environment by increasing the photosynthetic capability per unit area. With increasing altitude, P. viviparum populations may be sustained by investing less energy in vegetation and more in reproduction, especially asexual reproduction. © 2022 Science Press. All rights reserved.     

基于熵值法的驾驶人“路怒症”宏观影响因素研究*

为探究宏观因素对我国各区域驾驶人“路怒症”的影响,从经济发展、交通环境、气候状况和地域文化4个方面选取13项指标,采用熵值法赋权,构建我国区域路怒水平影响因素评价体系,对2019—2020年我国5座城市的驾驶人路怒水平进行分析和评价。研究结果表明:宏观因素对5座城市的路怒水平均有影响,而且城市之间路怒水平差异相对较大,总体呈现“北高南低”的空间分布特征,据此为各城市预防和控制路怒水平提出针对性建议,以促进城市交通安全发展。     

贵州喀斯特地区珍稀濒危植物及其保护

贵州73％的土地为碳酸盐岩覆盖，生态环境脆弱，喀斯特地貌极为发育是我国一个相对独特的地域环境单元，也是一个植物多样性较丰富的地区，仅需保护的珍稀濒危植物就有342种，分属84科193属。分析了贵州喀斯特地区珍稀濒危植物的现状特征，并从植物本身的生理生态习性，喀斯特生境本底的严酷性（如土壤瘠薄、方便利用的地表水匮乏等），人类干扰活动（如盗伐，毁林垦荒，水土流失，酸雨危害等）等方面探讨了该地区珍稀濒危物种的濒危原因。在此基础上，结合目前西部大开发中生态建设的要求，提出了该地区珍稀濒危植物保护应采取的七条对策建议。     

加拿大城市可持续性发展战略及对我国的启示

二战以来，全世界万其是发在国家与地区经历了城市化的快速发展以后，城市化的发展步入了以“质”为核 心的新阶段，城市的可持续性发展显得万为重要，并在全世界范围内展开了深入研究，而作为一个发展中国家，我们对城市可持续性发展研究相对较少。为此，我们以加拿大城市可持续性发展为例，详细介绍了加拿大面对城市的可持续性发展所采取的一系列措施，并针对我国的具体情况，提出了我国城市的可持续性发展应该注意的一些问题。     

Strategic Thinking for Sustainable Development of Mining-Based Cities in China

Cities based on mining are distinctive from other cities in China. Their heavy dependence on minerals, a relatively undiversified industrial structure, seriously damaged ecological environment and the rather low degree of openness have all reduced their competitiveness, and severely constrained and hindered their sustainable development. In this paper the authors will study mining-based cities from the perspective of sustainable development, first by having a critical review of their features, and then by researching into strategic options to support their sustainable development.     

资源,生存空间与扶贫战略

本文在对资源和人类生存空间的讨论中,提出了自然资源、经济资源和社会资源的概念以及人类生存空间的地理性、经济性和社会性,并从资源和人类生存空间的角度对贫困问题进行了分析,认为社会资源贫乏及社会空间狭小是贫困的主要原因,因此,如何从资源的整体性出发,开发贫困地区的社会资源、扩展生存的社会空间是制定扶贫战略的重点。     

可再生资源非线性收获的策略研究

本文运用非线性理论建立了可再生资源二次非线性收获的动力摸式。研究结果表明：为了保证可再生资源的可持缓利用、收获，必须把收获强度控制在一定的水平上，我们因此可以得到持续的最大产量。我们发现虽然对可再生资源的收获策略有线性和非线性之分，但是得到的可再生资源的最大持续收获量是相同的。因此，我们必须采用合理的可再生资源收获策略。避免可再生资源的过度利用和枯竭。我国可再生资源十分短缺，需正确处理好经济发展与可再生资源保护之问的关系，保护好我国珍贵的可再生资源对于我国的可持续发展具有重大的现实意义。     

绿色战略与企业绩效关系研究评述

本文从绿色战略的概念和动因出发,对绿色战略与企业绩效关系的理论和实证研究情况进行了评述。     

Application of risk based inspection in refinery and processing piping

In refineries and processing plants, the enormous amount of piping is more complex in distribution than other types of equipment. In general, compared with other types of equipment in these industries, more difficulty in inspection planning is encountered.

However, under-inspection or over-inspection can occur due to the lack of jurisdictional requirements on the inspection interval and method for piping, or the inspection interval being based only on piping service classifications in the existing regulations, such as API 570. This can result in unacceptable risks, along with costly loss of resources.

To lessen the piping risk level, more and more companies have adopted and applied risk based inspection (RBI) methodology, leading to risk reduction and cost benefits since the last decade. This study applied RBI methodology to optimize the inspection strategy of the piping in a refinery and petrochemical plants in Taiwan. Two actual case studies were corroborated better with quantitative RBI methodology than without the methodology in terms of risk and cost reductions.     

Ecological pressures on grassland ecosystems and their conservation strategies in Northern China

In this study,we identified ecological pressures on grassland ecosystems and adaptive countermeasures in Northern China.Our research revealed that the main sources of these pressures included population growth,economic development,resources exploitation,and global climate change,with human-related activities being overriding factors.Overgrazing was an important reason for grassland imbalance,causing soil erosion and desertification,especially during the sensitive spring greening phase.In steppe zones,commercial coal mining was destructive to the ecological environment.Regarding long-term strategies,we recommend that policy-makers devote more consideration to a new conceptual approach for transforming grasslands through shifting the focus from die grassland’s traditional production functions to meir ecological functions.Applying this concept,adaptive countermeasures should be developed to reduce human impacts based on the environmental capacities of grasslands.Moreover,we recommend the development of environment-friendly industries and reduction of pressures from human activities as effective measures for maintaining the balance between sustainable economic development and grassland conservation.Lastly,we suggest that restoration of degraded grasslands should conform to the principle of natural vegetation to further improve the ecological adaptability of plants and ecosystem stability.This study is expected to provide scientific support for policy-makers engaged in grassland protection.