正确看待社会生活中的“地位”问题

“地位”是一个复杂的社会学、经济学、政治学和心理学问题。它与社会的客观物质基础有关，与一定时代的社会经济政治等结构有关，也与一定社会的价值观有关。什么叫“地位”?按《现代汉语辞典》的解释，就是“人或团体在社会关系中所处的位置”。社会是一个人类共同体，

The Main Ecological Issues of Water-Level -Fluctuating Zone and The strategies in Three Gorges Reservoir Area

After the completion of the Three Gorges dam, a 30 m high water-level-fluctuating zone （WLFZ） will appear along the banks, and will form a seasonal wetland ecosystem. According to the program of storing water in the Three Gorges reservoir, the main ecological and environmental problems probably incurred in WLFZ are discussed, such as formation of contaminated belt along banks, appearance of epidemic diseases in the reservoir region （including urban districts）, aggravation of geologic disasters, degradation of biodiversity and exacerbation of the ecosystem vulnerability. Six items of strategies are put forward according to the causes, distributed features and trends of these problems in this paper.

The World Production and Trade of Rare Earth Elements： The Position of the Pacific Area

In this paper we analyze the characteristics of the so-called rare earth elements （REEs） and its industrial applications. We present the policy, or lack thereof, in the countries in the Pacific Rim for its mining and commerce, and the current and future weight that rare earth minerals will have in international trade. The technological revolution experienced over the last 25 years, has brought the REEs to the public＇s attention for being instrumental in obtaining catalysts, lasers and optical fiber, luminescent substances and LEDs, superconductors, permanent magnets, batteries and ultra-capacitors. China＇s leading position as the supplier of these minerals worldwide, and its recent export restriction policy for domestic industrial activities have driven up international prices. Price increase for REEs is leading to the need for both recycling and its replacement. It has also led other countries in the Asia Pacific Rim to prospect new potential sites on their own territories, or even to restart operations in deposits that had been previously abandoned. Those strategies will likely gain greater importance as environmental pollution problems associated with the exploitation, processing, and recovery of REEs increase.

An Range-free Localization Scheme for Large Scale Underwater Wireless Sensor Networks

In this paper, we study an area localization problem in large scale underwater wireless sensor networks （UWSNs）. The limited bandwidth, the severely impaired channel and the cost of underwater equipment all make the underwater localization problem very challenging. Exact localization is very difficult for UWSNs in deep underwater environment. We propose a range free method based on mobile detachable elevator transceiver （DET） and 3D multi-power area localization scheme （3D-MALS） to address the challenging problem. In the proposed scheme, the ideas of 2D multi-power area localization scheme （2D-ALS） and utilizing DET are used to achieve the simplicity, location accuracy, scalability and low cost performances. The DET can rise and get down to broadcast its position. And it is assumed that all the underwater nodes underwater have pressure sensors and know their z coordinates. We evaluate the performances of 2D-ALS and our proposed 3D-MALS schemes under both ideal and non-ideal channel propagation conditions, in terms of localization error and localization ratio. The simulation results show that our proposed scheme is much more efficient than the 2D-ALS.

Hybridization and the species problem in conservation

Most biologists recognize the ＂species phenomenon＂ as a real pattern in nature： Biodiversity is characterized by dis- continuities between recognizable groups classified as species. Many conservation laws focus on preventing species extinction. However, species are not fixed. Discontinuities evolve gradually and sometimes disappear. Exactly how to define particular spe- cies is not always obvious. Hybridization between taxonomic species reminds us that species classification is not a perfect repre- sentation of nature. Classification is a model that is very useful, but not adequate in all cases. Conservationists often confront questions about how to apply species-based laws when hybridization confounds classification. Development of sophisticated techniques and nuanced interpretation of data in the basic study of species and speciation has exposed the need for deeper educa- tion in genetics and evolution for applied conservationists and decision makers. Here we offer a brief perspective on hybridiza- tion and the species problem in conservation. Our intended audience is conservation practitioners and decision-makers more than geneticists and evolutionary biologists. We wish to emphasize that the goals and premises of legislative classification are not identical to those of scientific classification. Sometimes legal classification is required when the best available science indicates that discrete classification is not an adequate model for the case. Establishing legal status and level of protection for hybrids and hybrid populations means choosing from a range of scientifically valid alternatives. Although we should not abandon species-based approaches to conservation, we must recognize their limitations and work to clarify the roles of science and values in ethical and legal decisions [Current Zoology 61 （1）： 206-216, 2015].