移动通信基站景观影响评价方法与实践

为保护景区景观资源,降低对景观的影响,有必要开展风景区移动通信基站建设项目的景观影响评价。针对其建设特点,梳理了移动通信基站景观影响评价思路,探讨了评价方法。以南京玄武湖公园梁州基站为例,在景观敏感度和景观阚值评价的基础上,对3处基站拟建址的景观影响进行评价,给出评价结论和建议,对开展景观影响定量评价具有很好的参考价值。     

Is the Water Footprint an Appropriate Tool for Forestry and Forest Products: The Fennoscandian Case

The water footprint by the Water Footprint Network (WF) is an ambitious tool for measuring human appropriation and promoting sustainable use of fresh water. Using recent case studies and examples from water-abundant Fennoscandia, we consider whether it is an appropriate tool for evaluating the water use of forestry and forest-based products. We show that aggregating catchment level water consumption over a product life cycle does not consider fresh water as a renewable resource and is inconsistent with the principles of the hydrologic cycle. Currently, the WF assumes that all evapotranspiration (ET) from forests is a human appropriation of water although ET from managed forests in Fennoscandia is indistinguishable from that of unmanaged forests. We suggest that ET should not be included in the water footprint of rain-fed forestry and forest-based products. Tools for sustainable water management should always contextualize water use and water impacts with local water availability and environmental sensitivity.     

Measuring and modeling nitrous oxide and methane emissions from beef cattle feedlot manure management: First assessments under Brazilian condition

Intensive beef production has increased during recent decades in Brazil and may substantially increase both methane (CH₄) and nitrous oxide (N₂O) emissions from manure management. However, the quantification of these gases and methods for extrapolating them are scarce in Brazil. A case study examines CH₄ and N₂O emissions from one typical beef cattle feedlot manure management continuum in Brazil and the applicability of Manure-DNDC model in predicting these emissions for better understand fluxes and mitigation options. Measurements track CH₄ and N₂O emissions from manure excreted in one housing floor holding 21 animals for 78 days, stockpiled for 73 days and field spread (360 kg N ha^?1). We found total emissions (CH₄ + N₂O) of 0.19 ± 0.10 kg CO₂eq per kg of animal live weight gain; mostly coming from field application (73%), followed housing (25%) and storage (2%). The Manure-DNDC simulations were generally within the statistical deviation ranges of the field data, differing in ?28% in total emission. Large uncertainties in measurements showed the model was more accurate estimating the magnitude of gases emissions than replicate results at daily basis. Modeled results suggested increasing the frequency of manure removal from housing, splitting the field application and adopting no-tillage system is the most efficient management for reducing emissions from manure (up to about 75%). Since this work consists in the first assessment under Brazilian conditions, more and continuous field measurements are required for decreasing uncertainties and improving model validations. However, this paper reports promising results and scientific perceptions for the design of further integrated work on farm-scale measurements and Manure-DNDC model development for Brazilian conditions.     

一种用于电力通信的自适应Adhoc协议

针对电网通信的智能化监测应用需要,提出了一种用于电力通信的Adhoc自适应预约按需传输多址接入协议,该协议在接入阶段可以根据业务量动态调整接入策略;在传输阶段可以无冲突的发送分组.针对该协议的吞吐量和平均时延性能进行了仿真分析.分析结果表明：协议能提高信道利用率、降低接入时延,可用于现代电力通信网络,以上研究结果对Adhoe在电力通信的工程中应用有较好参考意义.     

基于元胞自动机的弱视条件下群体疏散的仿真研究

根据人在弱视情况下的行为特征,建立基于元胞自动机的逃生模型,对弱视情况下的人群疏散进行了模拟。模拟过程中考虑了人的学习能力及人与人之间的相互作用等因素,模型加入吸引子使模拟人的疏散行为更为灵活。基于人能通过熟悉周围环境作出合理判断的学习能力,引入了"积累步长"的概念,使人的沟通判断能力(走过的路径、边界和出口位置通过交流能够获取)在模型中得到体现。获取足够信息的人可以避免多余的寻找,降低了逃生时间,体现了"人多力量大"的互助行为。通过大量的模拟实验,并讨论不同的环境条件对人群疏散的影响。     

The modulation of worker behavior by the vibration signal during house hunting in swarms of the honeybee, Apis mellifera

During house hunting, honeybee, Apis melli- fera, workers perform the vibration signal, which may function in a modulatory manner to influence several aspects of nestsite selection and colony movement. We examined the role of the vibration signal in the house-hunting process of seven honeybee swarms. The signal was performed by a small proportion of the older bees, and 20% of the vibrating bees also performed waggle dances for nestsites. Compared to non-vibrating controls, vibrating bees exhibited increased rates of locomotion, were more likely to move into the interiors of the swarms, and were more likely to fly from the clusters and perform waggle dances. Recipients responded to the signal with increased locomotion and were more likely than non- vibrated controls to fly from the swarms. Because vibration signals were intermixed with waggle dances by some vibrators, and because they stimulated flight in recipients, the signals may have enhanced nestsite scouting and recruitment early in the house-hunting process. All swarms exhibited increased vibration activity within 0.5–1 h of departure. During these final periods, numerous vibrating bees wove repeatedly in and out of the clusters while signaling and motion on the swarms increased until it culminated in mass flight. The peaks of vibration activity observed at the end of the house-hunting process may therefore have activated the entire swarm for liftoff once a new nestsite had been selected. Thus, the vibration signal may help to integrate the behavior of numerous groups of workers during nestsite selection and colony relocation. Received: 17 January 2000 / Received in revised form: 5 April 2000 / Accepted: 3 May 2000     

Socioeconomic Dimensions of Changes in the Agricultural Landscape of the Mediterranean Basin: A Case Study of the Abandonment of Cultivation Terraces on Nisyros Island,Greece

Agricultural landscapes illustrate the impact of human actions on physical settings, and differential human pressures cause these landscapes to change with time. Our study explored changes in the terraced landscapes of Nisyros Island, Greece, focusing on the socioeconomic aspects during two time periods using field data, cadastral research, local documents, and published literature, as well as surveys of the islanders. Population increases during the late 19^th to early 20^th centuries marked a significant escalation of terrace and dry stone wall construction, which facilitated cultivation on 58.4% of the island. By the mid-20^th century, the economic collapse of agricultural activities and consequent emigration caused the abandonment of cultivated land and traditional management practices, dramatically reducing farm and field numbers. Terrace abandonment continued in recent decades, with increased livestock grazing becoming the main land management tool; as a result, both farm and pasture sizes increased. Neglect and changing land use has led to deterioration and destruction of many terraces on the island. We discuss the socioeconomic and political backgrounds responsible for the land-use change before World War II (annexation of Nisyros Island by the Ottoman Empire, Italy, and Greece; overseas migration opportunities; and world transportation changes) and after the war (social changes in peasant societies; worldwide changes in agricultural production practices). The adverse landscape changes documented for Nisyros Island appear to be inevitable for modern Mediterranean rural societies, including those on other islands in this region. The island’s unique terraced landscapes may qualify Nisyros to become an archive or repository of old agricultural management techniques to be used by future generations and a living resource for sustainable management.     

Vegetarian Meat: Could Technology Save Animals and Satisfy Meat Eaters?

Between people who unabashedly support eating meat and those who adopt moral vegetarianism, lie a number of people who are uncomfortably carnivorous and vaguely wish they could be vegetarians. Opposing animal suffering in principle, they can ignore it in practice, relying on the visual disconnect between supermarket meat and slaughterhouse practices not to trigger their moral emotions. But what if we could have the best of both worlds in reality—eat meat and not harm animals? The nascent biotechnology of tissue culture, originally researched for medical applications, holds out just such a promise. Meat could be grown in vitro without killing animals. In fact, this technology may not just be an intriguing option, but might be our moral obligation to develop.     

Image Themes and Frames in US Print News Stories about Climate Change

Research on frames in climate change (CC) news coverage has advanced substantially over the past decade, but the emerging understanding of the framing role of visual imagery that often accompanies news texts remains fragmented. We report on a set of image frames identified through content analysis of 350 images associated with 200 news articles from 11 US newspaper and magazine sources from 1969 through late 2009. We reliably identified and quantified the occurrence of 118 image themes. We then hierarchically clustered the themes based on their co-occurrence in images to identify an integrated framework of 42 image frames. We highlight frames associated with particular types of images (e.g., photographs and maps) or geographic regions. From among the full set of frames, we identify 15 that commonly appear in US CC news imagery and discuss the ways in which image frames make salient (or render invisible) particular categories of people, geographic regions, aspects of science, and spheres of activity.     

Uptake and translocation of sulfamethazine by alfalfa grown under hydroponic conditions

Antibiotics are routinely used in intensive animal agriculture operations collectively known as Concentrated Animal Feed Operations(CAFO) which include dairy, poultry and swine farms. Wastewater generated by CAFOs often contains low levels of antibiotics and is typically managed in an anaerobic lagoon. The objective of this research is to investigate the uptake and fate of aqueous sulfamethazine(SMN) antibiotic by alfalfa(Medicago sativa)grass grown under hydroponic conditions. Uptake studies were conducted using hydroponically grown alfalfa in a commercially available nutrient solution supplemented with 10 mg/L of SMN antibiotic. Analysis of alfalfa sap, root zone, middle one-third, and top portion of the foliage showed varying uptake rate and translocation of SMN. The highest average amount of SMN(8.58 μg/kg) was detected in the root zone, followed by the top portion(1.89 μg/kg), middle one-third(1.30 μg/kg), and sap(0.38 μg/kg) samples, indicating a clear distribution of SMN within the sampled regions. The ultraviolet(UV) spectra of parent SMN and translocated SMN identified in different parts of the plant present the possibility of metabolization during the uptake process. Uptake of SMN using alfalfa grown under hydroponic conditions has potential as a promising remediation technology for removal of similar antibiotics from wastewater lagoons.