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61.
The strongest observed solar magnetic fields are found in sunspot umbrae and associated light bridges. We investigate systematic measurements of approximately 32 000 sunspot groups observed from 1917 through 2004 using data from Mt. Wilson, Potsdam, Rome and Crimea observatories. Isolated observations from other observatories are also included. Corrections to Mt. Wilson measurements are required and applied. We found 55 groups (0.2%) with at least one sunspot with one magnetic field measurement of at least 4000 G including five measurements of at least 5000 G and one spot with a record field of 6100 G. Although typical strong-field spots are large and show complex structure in white light, others are simple in form. Sometimes the strongest fields are in light bridges that separate opposite polarity umbras. The distribution of strongest measured fields above 3 kG appears to be continuous, following a steep power law with exponent about −9.5. The observed upper limit of 5 – 6 kG is consistent with the idea that an umbral field has a more or less coherent structure down to some depth and then fragments. We find that odd-numbered sunspot cycles usually contain about 30% more total sunspot groups but 60% fewer >3 kG spots than preceding even-numbered cycles.  相似文献   
62.
63.
The relative contributions of adsorption to particulate surfaces, complexation with surface-active organic ligands and uptake by micro-organisms were evaluated with respect to their importance in the surface microlayer enrichment (‘partitioning’) of Cd, Pb and Cu. The contributions of each process were inferred from field data in which partitioning of the dissolved and particulate forms of Cd, Pb and Cu, total and dissolved organic carbon, particles and total bacteria were observed. In the South San Francisco Bay estuary, particle enrichment appears to control trace metal partitioning. Trace metal association with the particulate phase and the levels of partitioning observed were in the order Pb > Cu > Cd and reflect the calculated equilibrium chemical speciation of these metals in computer-simulated seawater matrices.  相似文献   
64.
From the demand-side, the clients and the student practitioner, TARP was a success. Although some students were not overly enthusiastic, they were exposed to a large set of new ideas and presented new skills to equip them in the transition to multimodal transportation. Local Caltrans directors were pleased with TARP. From the supply side, JCTS, the faculty, and the CSUC Consortium, TARP was a partial success. The positive elements accruing to the faculty have been mentioned. Some of the negative elements of TARP such as high initial cost occurred because of the innovative nature and the grand scale of the program. The pool of potential faculty was probably too small to permit the degree of course specialization planned for in all five locations and given the decentralized approach. Three locations would have been better from the supply-side point of view. While certain difficulties remain with such educational programs in areas of identification of clients and their needs in planning, marketing, and teaching, a rich harvest of knowledge and rapport can accrue. Returned research dollars from agencies, interdisciplinary cooperation among professors, sharing of data and equipment by agencies for student theses and, in general, a larger role for geography programs in the state and local regions are recognized as benefits. Certain geography programs that have the required expertise to initiate such applied geographic educational efforts on a more modest scale must be prepared to take the plunge. They offer a unique perspective.  相似文献   
65.
Observations of interplanetary magnetic field polarity, solar wind speed, and geomagnetic disturbance index (C9) during the years 1962–1975 are compared in a 27-day pictorial format that emphasizes their associated variations during the sunspot cycle. This display accentuates graphically several recently reported features of solar wind streams including the fact that the streams were faster, wider, and longer-lived during 1962–1964 and 1973–1975 in the declining phase of the sunspot cycle than during intervening years (Bame et al., 1976; Gosling et al., 1976). The display reveals strikingly that these high-speed streams were associated with the major, recurrent patterns of geomagnetic activity that are characteristic of the declining phase of the sunspot cycle. Finally, the display shows that during 1962–1975 the association between long-lived solar wind streams and recurrent geomagnetic disturbances was modulated by the annual variation (Burch, 1973) of the response of the geomagnetic field to solar wind conditions. The phase of this annual variation depends on the polarity of the interplanetary magnetic field in the sense that negative sectors of the interplanetary field have their greatest geomagnetic effect in northern hemisphere spring, and positive sectors have their greatest effect in the fall. During 1965–1972 when the solar wind streams were relatively slow (500 km s-1), the annual variation strongly influenced the visibility of the corresponding geomagnetic disturbance patterns.Visiting Scientist, Kitt Peak National Observatory, Tucson, Arizona.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.  相似文献   
66.
Observations of the longitudinal magnetic field of several prominences were made with the D3, H, and H lines. There is no significant difference in the magnetic field measured with the helium and hydrogen lines. The possibility of a true difference in the fields on a scale much finer than that of our observations is not excluded.  相似文献   
67.
Spectroscopic determinations of solar rotation   总被引:2,自引:0,他引:2  
Spectral line shift data obtained from full-disk magnetograms recorded at Mt. Wilson are analyzed for differential rotation. The method of analysis is discussed and the results from the data for 1966 through 1968 are presented. The average equatorial velocity over this period is found to be 1.93 km/sec or 13.76 deg/day (sidereal). This corresponds to a sidereal period of 26.16 days. The average results are = 2.78 × 10-6 - 3.51 × 10-7 sin2 B - 4.43 × 10-7 sin4 B rad/sec, whereB is the solar latitude. This indicates a smaller decrease of angular velocity with latitude than found by earlier investigators. Variations from day to day are caused by large-scale short-lived velocity fields on the solar surface. There also appear to be secular variations.Currently at the Kitt Peak National Observatory, Tucson, Arizona.  相似文献   
68.
Harvey Neo 《Geoforum》2009,40(2):260-268
Rising demand for meat has led to changing modes of production in the livestock industry and prompted varied institutional and regulatory changes. For the most part, the latter are enabling measures not fundamentally aimed at restraining the overall growth of the industry. In other words, specific institutional changes are meant to reduce uncertainty by providing a structure to everyday life although at a broader spatial scale, an institutional approach suggests that (a region’s) social infrastructure can help or hinder economic growth. In tracing recent developments in the Malaysian pig industry, this paper highlights an institutional regime that is stable on the surface but is in actuality prone to destabilization. Specifically, the role of cultural politics in shaping, sustaining and destabilizing institutional behavior and regimes will be examined, using the case study of the Malaccan pig industry. In explicating how institutional regimes and development are stabilized and destabilized, the paper argues that cultural politics might be an intractable stumbling block to the future growth and development of the industry.  相似文献   
69.
Indonesia has become the world's largest exporter of thermal coal and is a major supplier to the Asian coal market, particularly as the People's Republic of China is now (2007) and perhaps may remain a net importer of coal. Indonesia has had a long history of coal production, mainly in Sumatra and Kalimantan, but only in the last two decades have government and commercial forces resulted in a remarkable coal boom. A recent assessment of Indonesian coal-bed methane (CBM) potential has motivated active CBM exploration. Most of the coal is Paleogene and Neogene, low to moderate rank and has low ash yield and sulfur (generally < 10 and < 1 wt.%, respectively). Active tectonic and igneous activity has resulted in significant rank increase in some coal basins. Eight coal samples are described that represent the major export and/or resource potential of Sumatra, Kalimantan, Sulawesi, and Papua. Detailed geochemistry, including proximate and ultimate analysis, sulfur forms, and major, minor, and trace element determinations are presented. Organic petrology and vitrinite reflectance data reflect various precursor flora assemblages and rank variations, including sample composites from active igneous and tectonic areas. A comparison of Hazardous Air Pollutants (HAPs) elements abundance with world and US averages show that the Indonesian coals have low combustion pollution potential.  相似文献   
70.
Although local knowledge is a crucial source of information for fishery development, its generally unsystematic presentation and nebulous content makes use by policy makers or managers difficult. Based on field data obtained using Participatory Rural Appraisal at Bang Saphan Bay, Prachuap Khiri Khan Province, Thailand, we attempt to show here how local knowledge can be effectively systematized, analyzed and displayed visually using a Geographical Information System (GIS) for use in fisheries management. PRA data on location fished, time of fishing, techniques and technology used and species targeted were obtained from local fishers then mapped using Arcview (3.1). In this way local fisheries knowledge can be converted into geo-spatial data form via GIS, and the succinct results used easily to guide fishery management and planning, especially by offering directions for rights-based fisheries and co-management.  相似文献   
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