能量效率与可更新能源

一可更新能源可减少甚至消除我们对化石能和核能的依赖,其中很多虽然已为人类使用数百年,但因为石能的普遍使用,一直都为起人类的注意。人类已发明了新技术利用这些可更新能源。其利用不赖于一定的技术是既定的事实,目前有成功建立这样的能源工业还是十分昂贵的。如果人类生产经济和市场允许的话,这些新的技术经进一步改进和简化后,就可以降低成本,并且应用起来也很可靠。相对于开发应用核能,水能和化石能数以百万计的投资耗费来讲,用于可更新资源的资金可谓微乎其微。虽然传统能源和替代能源各具优点,但保护能源往往还是解决能源短缺最便宜,最容易的途径。     

能量效率与可更新能源

一些可更新能源可减少甚至消除我们对化石能和核能的依赖,其中很多虽然已为人类使用数百年,但因为化石能的普遍使用,一直都为起人类的注意。人类已发明了新技术来利用这些可更新能源。其利用有赖于一定的技术是既定的事实,目前有成功建立这样的能源工业还是十分昂贵的。如果人类生产经济和市场允许的话,这些新技术经进一步改进和简化后,就可以降低成本,并且应用起来也很可靠。相对于开发应用核能,水能和化石能数以百万计的投资耗费来讲,用于可更新资源的资金可谓微乎其微。虽然传统能源和替代能源各具优点,但保护能源往往还是解决能源短缺最便宜,最容易的途径。     

Earth,Air, Fire,and Water: Elements of Art

Abstract

Shoshana Zuboff. In the Age of the Smart Machine: The Future of Work and Power. New York: Basic Books, 1988, 468 pp. $11.95 paperback.

George Gilder. Microcosm: The Quantum Revolution in Economics and Technology. New York: Simon &; Schuster, 1989. 426 pp. $19.95 hardcover.

Loren Baritz. The Good Life. New York: Alfred A. Knopf, Inc., 1988. 361 pp. $19.95 hardcover.

Miles Orville. The Real Thing: Imitation and Authority in American Culture, 1880–1940. Chapel Hill: University of North Carolina Press, 1989. 382 pp. $14.95 paperback.

Peter Shaw. The War Against the Intellect. Iowa City: The University of Iowa Press, 1989. 181 pp. $10.95 paperback.

Robert Alter. The Pleasures of Reading in an Ideological Age. New York: Simon &; Schuster, 1989. 250 pp. $18.95 hardcover.

Ian Crofton. A Dictionary of Art Quotations. New York: Macmillan Publishing Company, 1989. $19.95 hardcover.     

Water quality response to the Angora Fire, Lake Tahoe, California

The Angora Fire (summer of 2007) was the largest and most severe wildfire in recent history within the Lake Tahoe basin of the Sierra Nevada. To determine the watershed response and to assess the potential for downstream impacts of nutrient and sediment delivery to Lake Tahoe, we monitored the post-fire hydrology and stream water chemistry for 2 years at four locations along the length of Angora Creek, a perennial stream draining the burned watershed. When compared with unburned streams, the hydrology of Angora Creek indicated an earlier and faster melting of the spring snowpack. Peak stream water concentrations of total N (TN) and ammonium occurred within the burned area, whereas peak concentrations of nitrate (NO₃ ^?), total P, soluble reactive P, total suspended solids, turbidity, electrical conductivity (EC), and dissolved organic C occurred below the burned area. In comparison to pre-fire data, TN, NO₃ ^?, TP, total dissolved P, EC, and turbidity increased following the fire, particularly in the wetter second year. Yields for subwatershed areas suggest that the burned urban subwatershed was the largest source of nutrients and sediments, whereas the wet meadow subwatershed downstream of the burned area retained materials. Erosion control efforts, below-average annual precipitation and the timing of its arrival (absence of summer and fall rainstorms), and the existence of a wet meadow below the burned watershed likely reduced the negative impacts that would have been expected from such a severe wildfire.     

Regional Scale Prioritisation for Key Ecosystem Services,Renewable Energy Production and Urban Development

Although the importance of addressing ecosystem service benefits in regional land use planning and decision-making is evident, substantial practical challenges remain. In particular, methods to identify priority areas for the provision of key ecosystem services and other environmental services (benefits from the environment not directly linked to the function of ecosystems) need to be developed. Priority areas are locations which provide disproportionally high benefits from one or more service. Here we map a set of ecosystem and environmental services and delineate priority areas according to different scenarios. Each scenario is produced by a set of weightings allocated to different services and corresponds to different landscape management strategies which decision makers could undertake. Using the county of Cornwall, U.K., as a case study, we processed gridded maps of key ecosystem services and environmental services, including renewable energy production and urban development. We explored their spatial distribution patterns and their spatial covariance and spatial stationarity within the region. Finally we applied a complementarity-based priority ranking algorithm (zonation) using different weighting schemes. Our conclusions are that (i) there are two main patterns of service distribution in this region, clustered services (including agriculture, carbon stocks, urban development and plant production) and dispersed services (including cultural services, energy production and floods mitigation); (ii) more than half of the services are spatially correlated and there is high non-stationarity in the spatial covariance between services; and (iii) it is important to consider both ecosystem services and other environmental services in identifying priority areas. Different weighting schemes provoke drastic changes in the delineation of priority areas and therefore decision making processes need to carefully consider the relative values attributed to different services.     

The Flight Behavior of Migrating Birds in Changing Wind Fields: Radar and Visual Analyses

This paper examines the influence of atmospheric structure andmotion (principally winds aloft) on the flight behavior andaltitudinal distribution of migrating songbirds. Bird migrationdata that I gathered using surveillance radars operated by theUnited States National Weather Service and the Federal AviationAdministration and a vertically directed fixed-beam marine radarmounted on a mobile laboratory are analyzed in relation to windsaloft. Migrating birds appear to fly at altitudes where windswill minimize the cost of transport and assist movements inseasonally appropriate directions. When migratory flights occurat altitudes that are higher than usual, a significant correlationexists between the altitude of densest migration and the altitudeof most favorable wind. Lower altitudes may be favored overslightly more favorable winds at much higher altitudes. Radardata on the flight behavior of migrating birds in the vicinityof frontal systems is also examined. The flight strategies ofmigrants (fly over the front, change the direction of flight,or land and terminate the flight) differ depending on seasonand the "thickness" of the front. Recent migration studies thatare related to atmospheric structure and motion are summarizedand related to atmospheric processes operating simultaneouslyat vastly different spatial and temporal scales.     

Of Mice,Birds, and Men: The Mouse Ultrasonic Song System Has Some Features Similar to Humans and Song-Learning Birds

Humans and song-learning birds communicate acoustically using learned vocalizations. The characteristic features of this social communication behavior include vocal control by forebrain motor areas, a direct cortical projection to brainstem vocal motor neurons, and dependence on auditory feedback to develop and maintain learned vocalizations. These features have so far not been found in closely related primate and avian species that do not learn vocalizations. Male mice produce courtship ultrasonic vocalizations with acoustic features similar to songs of song-learning birds. However, it is assumed that mice lack a forebrain system for vocal modification and that their ultrasonic vocalizations are innate. Here we investigated the mouse song system and discovered that it includes a motor cortex region active during singing, that projects directly to brainstem vocal motor neurons and is necessary for keeping song more stereotyped and on pitch. We also discovered that male mice depend on auditory feedback to maintain some ultrasonic song features, and that sub-strains with differences in their songs can match each other''s pitch when cross-housed under competitive social conditions. We conclude that male mice have some limited vocal modification abilities with at least some neuroanatomical features thought to be unique to humans and song-learning birds. To explain our findings, we propose a continuum hypothesis of vocal learning.     

Birds, bugs and blood: avian parasitism and conservation

Parasitism has far-reaching implications not only for the ecology and evolution of species but also for conservation. The effects of blood-feeding ectoparasites on colonially nesting bird species have been wodely studied, but recent surprising reports show that solitarily nesting species are also commonly attacked, mainly by the larvae of flies. Most bird species are solitary nesters; as their habitats are increasingly fragmented, how will the potential for such parasitism be affected? One example is that of the endangered Puerto Rican parrot (Amazona vittata), in which habitat changes have introduced a deadly parasitic fly species in a complex and unpredicted manner. As theories on habitat fragmentation outpace the data, we need to carry out more field studies of the interactions between fragmentation and parasitism, and to include parasitism in species survival and recovery plans.