Using Socioeconomic and Fisheries Involvement Indices to Understand Alaska Fishing Community Well-Being

Over recent years, fisheries managers have been going through a paradigm shift to prioritize ecosystem-based management. With this comes an increasing need to better understand the impacts of fisheries management decisions on the social well-being and sustainability of fishing communities. This article summarizes research aimed at using secondary data to develop socioeconomic and fisheries involvement indices to measure objective fishing community well-being in Alaska. Data from more than 300 communities in Alaska were used to create a database of socioeconomic and fisheries involvement indices of objective well-being and adaptability for Alaska communities dependent on marine resources. Each index was developed using a principal components factor analysis to assess the relative position of each community compared to all other communities in Alaska. We find that creating performance measures, such as the indices presented here, provides a useful way to track the status of socioeconomic conditions and fisheries involvement by communities over time.     

Top-down effects and carbon flux in the ocean: A hypothesis

The close relationships between mesozooplankton, chlorophyll, and primary production normally observed across latitudes may be regarded as a bottom-up effect of increased productivity or, conversely, as a top-down effect of mesozooplankton on microzooplankton, releasing phytoplankton growth. The time-course of primary producers and mesozooplankton observed during the Late Winter Bloom in subtropical waters suggests a top-down effect, similar to the results found in lakes and mesocosm experiments. Two scenarios were observed during the development of the bloom in the Canary Island waters. The first was the increase in mesozooplankton as the effect of higher primary production due to mixing. The second scenario was the decrease in mesozooplankton due to the top-down effect of predation by diel vertical migrants upon epipelagic mesozooplankton. The structure of the food web in the euphotic zone was different depending on the presence or not of mesozooplankton, suggesting important consequences for the transport of carbon in those large areas of the ocean.     

Hydrographic structure and zooplankton abundance and diversity off Paita, northern Peru (1994 to 2004) — ENSO effects, trends and changes

The objective of the present study was to verify possible spatial, seasonal, and inter-annual changes in the zooplankton off Paita (northern Peru), an upwelling area located closely to the limits of cold Humboldt Current and warm Equatorial Surface Waters. Zooplankton was sampled at subsurface on 53 occasions from August 1994 to December 2004 at four stations located 2 to 30 km offshore with a WP-2 net (300 µm). Extremely high surface water temperatures combined with low salinities were observed during the 1997/98 El Niño up to 29.0 °C) and in April 2002 (up to 25.0 °C). Temperatures more than 2 °C above monthly average were also observed in October 1994, in April 2000, and in November 2004. Significant trends were observed for oxygen concentration (increase) and several horizontal and vertical gradients. Among the copepods (72% of all individuals), the most abundant species were Paracalanus parvus (28%), Acartia tonsa (26%), and Calanus sp. (10%). The strong 1997–98 El Niño (EN) event led to drastic changes in species composition that were reversed during the 1998–99 La Niña (LN) event. Community parameters such as total abundance, diversity, equitability and species richness displayed marked variations associated with the 1997–98 EN and long-term trends. Long-term trends were significant for several vertical and horizontal temperature and oxygen gradients, indicating an increase in upwelling intensity at the shelf during the study period. 10-year-trends were also significant for total zooplankton abundance (increase) and community evenness (J, decline). Our data confirmed the importance of the weak EN in 2002/03 for the study region. Within the trend of increasing zooplankton abundance, a sharp step or shift was observed from 1999 to 2000. When using sequential t-tests to detect shifts in (x + 1) transformed abundance data, a significant rupture was found between the last sampling in 1999 and the first sampling in 2000. Also, a substantial decrease in diel variability occurred after 1999, probably due to changes in vertical migration patterns. The considerable increase in zooplankton abundance over the study period, the ENSO effect, and the 1999–2000 transition are discussed with regard to synchronicity with other zooplankton time series. The present study contributes with the first evidence from an important area located in the Humboldt Current for synchronous trends and changes that were previously observed elsewhere in the Pacific. Our results demonstrated the importance of long-term zooplankton monitoring studies in upwelling areas, and confirms the idea of dramatic changes in pelagic ecosystem structure occurring in the East Pacific.     

浅论虚拟社区营销

本文针对目前蓬勃发展的网络虚拟社区,介绍了虚拟社区的特点以及我国虚拟社区发展的现状,分析了虚拟商品在虚拟社区中的价值,着重阐述了现实企业在虚拟社区中应该采用的营销策略     

Identifying the spatial distribution of public transportation trips by node and community characteristics

ABSTRACT

Identifying the spatial distribution of travel activities can help public transportation managers optimize the allocation of resources. In this paper, transit networks are constructed based on traffic flow data rather than network topologies. The PageRank algorithm and community detection method are combined to identify the spatial distribution of public transportation trips. The structural centrality and PageRank values are compared to identify hub stations; the community detection method is applied to reveal the community structures. A case study in Guangzhou, China is presented. It is found that the bus network has a community structure, significant weekday commuting and small-world characteristics. The metro network is tightly connected, highly loaded, and has no obvious community structure. Hub stations show distinct differences in terms of volume and weekend/weekday usage. The results imply that the proposed method can be used to identify the spatial distribution of urban public transportation and provide a new study perspective.     

考虑交通环境影响的封闭小区开放决策研究

封闭小区的开放可以增加城市道路网密度，缓解交通拥堵，但目前封闭小区开放方案的决策方式单一，且未考虑开放后给小区带来的汽车尾气和交通噪声污染问题。将交通环境影响纳入考量范围，以行程时间、尾气排放和交通噪声构成的总目标费用函数值最小作为优化目标。引入封闭小区是否开放、单双行和限速这3种决策方式，建立上层系统费用最优和下层用户均衡的封闭小区开放双层决策模型，并利用遗传算法和Frank-Wolfe算法分别对上、下层模型进行求解。 对模型优化效果进行验证分析，结果表明，所建模型最优解的费用值相对偏差为0.67%，应用此模型后同比节省费用平均值为11.80%。对比分析得到：合理设置封闭小区开放的3种决策方式，可 以减少车辆行程时间和绕行距离，降低出行者的出行费用和考虑交通环境影响的附加费用，且采取相对较高的限速值有利于降低出行总费用值。     

Public service obligations for air transport in the United States and Europe: Connectivity effects and value for money

Public service obligations (PSOs) are used by governments in many countries, including the United States and 11 countries in Europe, to mandate a minimum level of commercial air transportation service, especially for small or rural communities. This paper analyzes PSOs in these 12 countries for the year 2010 using the recently proposed Global Connectivity Index to measure direct and indirect market access and a novel subsidy database covering 90% of PSO movements in these countries to assess value-for-money.We show that PSO services represent about 2.5% of all commercial movements in the 12 countries analyzed, generating about 1% of these countries’ total air transport connectivity. Over all routes for which data was available, approximately USD$ 900 million was earmarked for PSO and air service discount provision in 2010, with average subsidies per movement ranging from about $700 to $3500. PSO market access and efficiency outcomes vary across the countries analyzed. Some countries, such as Germany and the United States, focus on providing network access for smaller communities, thereby creating not only point-to-point, but also onward connectivity, while others such as Norway, Sweden, and Ireland, predominantly aim at providing “lifeline services” that connect remote regions to a nearby economic center without providing onward connections.     

西安市社区拼车常态化发展策略

伴随西安市私人小汽车保有量迅速增长,城市交通拥堵状况不断加剧,社区拼车模式成为缓解交通拥堵的有效措施之一。通过分析总结国内外拼车发展经验,采用问卷调查、访谈等方法对西安市拼车现状和发展问题进行解析。针对现状问题,提出社区拼车的实施策略:第一,成立社区拼车机构,通过拼车服务平台、社区拼车站点和社区拼车标志等措施管理拼车出行;第二,提供安全保障措施,通过设立实名认证体系、签订社区拼车协议、增加险种等措施保障拼车安全;第三,寻求政策支持,建议通过赋予多人乘坐的拼车车辆道路优先使用权、完善相关法律法规使拼车合法化、提供停车优惠政策等措施鼓励市民拼车。     

A “horizontal Sverdrup mechanism” may control the spring bloom around small oceanic islands and over banks

One of the most basic paradigms in marine ecology is the “Sverdrup mechanism,” where the spring bloom is retarded if the surface mixed layer is too deep, due to the algae being mixed vertically out of the euphotic layer. A similar mechanism may operate in vertically homogeneous water over a small shallow area, surrounded by deep waters, if the horizontal exchange is sufficiently intense. In systems with inter-annual variations in the horizontal exchange rate, this may induce inter-annual variations in the timing and intensity of the spring bloom. A numerical primary production model with circular symmetry and prescribed horizontal exchange rate is developed. Using the Faroe Shelf as an example, the model and observations show that the timing and intensity of the spring bloom in the shallow parts of the system may be critically dependent upon the rate of the horizontal exchange. Numerical experiments confirm that the effect of horizontal exchange on the spring bloom is less pronounced for banks than for shelf systems around islands of similar scales, and that the effect increases in importance as the horizontal scale is reduced.     

Community structure of mesopelagic copepods (>500 μm) in the Ligurian Sea (Western Mediterranean)

The distribution of mesopelagic copepods between 250 and 1000 m depth was studied along a transect off the coast of Villefranche-sur-Mer in June 1991 by means of a BIONESS multiple-net sampler. Among the most abundant species at all stations were Pleuromamma gracilis, Paraeuchaeta acuta and overwintering Calanus helgolandicus CV copepodites, each species inhabiting different depth layers with maximum abundances in the 250–350 m, 450–550 m and the 700–850 m layer, respectively. Cluster analysis of the vertical distribution of all species caught revealed three distinct strata (‘TOP', ‘INTERMEDIATE', ‘BOTTOM') consisting of characteristic species that occurred in the same stratum at all stations. Differences in total abundances of the species assemblage occupying each layer are discussed with regard to predation pressure by mesopelagic macroplanktonic crustaceans and fish. We show that each stratum is characterized by distinct trophic interactions and life strategies, which play an important role in the structuring of mesopelagic zooplankton communities.