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51.
Jim Whitman 《GeoJournal》1994,34(2):167-175
In the Post-Cold War environment, the role of the military has been extended to include intra-state peace enforcement on humanitarian grounds. This raises issues of legality. In this paper, four arguments are advanced that a right of states to intervene in humanitarian emergencies now exists. Problems contingent upon such intervention are then examined. 相似文献
52.
53.
The ground-water flow and ground-water quality of extensive gravel deposits in the Lower Colne Valley, near London, England are described. The great demand for aggregates in southeast England over the past 30 years has resulted in extensive exploitation of these gravels, the worked-out pits being either left water-filled for recreational purposes, or filled with a variety of waste materials. Both after-uses are shown to alter the ground-water situation either by locally lowering or raising ground-water levels, such effects having been described in both French and German literature, or by causing ground-water and surface-water pollution problems. If the scale of pit development or landfilling is large as in the Lower Colne Valley, then remedial measures have to be undertaken to minimize the pollution risk and to obviate problems caused by raised or lowered ground-water levels. 相似文献
54.
Concentrations of the members of the 238U decay chain and 232Th were determined in volcanic rocks from convergent plate margins, intraplate volcanoes and oceanic spreading centers. Contemporary and historical volcanic rocks from Mt. St. Helens, Arenal, El Chichon, Hawaii and Iceland and submarine basaltic glass from the Galapagos spreading center all show no fractionation of U and Th in the mantle source or during magma formation at least for the past 300,000 years. Mauna Kea (Hawaii) rocks of alkaline composition greater than 4000 years old and an old submarine basalt show disequilibrium for several of the nuclides in the 238U decay chain. We interpret these as resulting from post-emplacement processes. 相似文献
55.
L. Alados-Arboledas J. I. Jiménez Y. Castro-Díez 《Theoretical and Applied Climatology》1986,37(1-2):84-89
Summary Data on thermal radiation from clear skies obtained at Granada from May to November 1983 were utilized to carry out a detailed comparison between measured and calculated values of longwave radiation with several analytical and empirical equations. The goal of this work is to check the aplicability of these equations to Granada conditions. The results obtained for all the equations are quite satisfactory. Nevertheless, Idso's formula significantly overestimates our experimental results, probably as a consequence of the differences in atmospheric dust conditions between our test area and the location for which that equation was originally derived. A reduction in the independent coefficient, in accordance with previous results of other authors, provides a better fit to our data set and clearly shows the climatological dependence of the constants in the estimation equations.
With 3 Figures 相似文献
Zusammenfassung Die von Mai bis November 1983 in Granada gesammelten Daten über Wärmestrahlung bei klarem Himmel wurden dazu verwendet, um einen detaillierten Vergleich zwischen gemessenen und errechneten Werten der langwelligen Strahlung aus verschiedenen analytischen und empirischen Gleichungen durchzuführen. Das Ziel dieser Arbeit ist es, die Anwendbarkeit dieser Gleichungen auf die Verhältnisse in Granada zu überprüfen. Die gewonnenen Ergebnisse sind für alle diese Gleichungen ganz zufriedenstellend. Idsos Formel überschätzt jedoch deutlich unsere experimentellen Ergebnisse, möglicherweise als Folge der unterschiedlichen atmosphärischen Staubbedingungen in unserem Testgebiet und dem Standort, für den die Gleichung ursprünglich abgeleitet wurde. Eine Reduktion des unabhängigen Koeffizienten, in Übereinstimmung mit früheren Ergebnissen anderer Autoren, bietet eine bessere Anpassung an unseren Datensatz und zeigt deutlich die klimatologische Abhängigkeit der Konstanten in Schätzungsgleichungen.
With 3 Figures 相似文献
56.
In the tidal Potomac River, high river discharges during the spring are associated with high chlorophylla concentrations in the following in the following summer, assuming that summertime light and temperature conditions are favorable. Spring floods deliver large loads of particulate N and P to the tidal river. This particulate N and P could be mineralized by bacteria to inorganic N and P and released to the water column where it is available for phytoplankton use during summertime. However, during the study period relatively low concentrations of chlorophylla (less than 50 μg l?1 occurred in the tidal river if average monthly discharge during July or August exceeded 200 m3s?1. Discharge and other conditions combined to produce conditions favorable for nuisance levels of chlorophylla (greater than 100 μg l?1 approximately one year out of four. Chlorophylla maxima occurred in the Potomac River transition zone and estuary during late winter (dinoflagellates) and spring (diatoms). Typical seasonal peak concentrations were achieved at discharges as high as 970 m3 s?1, but sustained discharges greater than 1,100 m3 s?1 retarded development. Optimum growth conditions occurred following runoff events of 10 to 15 d duration which produced transit times to the transition zone of 7 to 10 d. Wet years with numerous moderate-sized runoff events, such as 1980, tend to produce greater biomass in the transition zone and estuary than do dry years such as 1981. 相似文献
57.
Jim C. Loftis Jane Harris Robert H. Montgomery 《Ground Water Monitoring & Remediation》1987,7(1):72-76
The Resource Conservation and Recovery Act (PL 94–580) and related federal and state legislation have mandated routine monitoring of ground water quality at regulated facilities. The objective of the required monitoring activities is detection of adverse changes in ground water quality caused by the facilities.
Both failure to detect pollution and an incorrect determination of pollution can be very expensive. It is crucial, therefore, that monitoring programs be designed and operated to provide statistically sound information. It is equally important that users of ground water quality data understand the nature and limitations of information from monitoring.
To address the preceding issues, the authors present a general approach to analyzing ground water quality data in light of the stated monitoring objective. The suggested approach accounts for "natural" variation in background water quality through pairing of observations. The limitations of quarterly sampling for detecting small changes in quality over a short time frame are discussed. 相似文献
Both failure to detect pollution and an incorrect determination of pollution can be very expensive. It is crucial, therefore, that monitoring programs be designed and operated to provide statistically sound information. It is equally important that users of ground water quality data understand the nature and limitations of information from monitoring.
To address the preceding issues, the authors present a general approach to analyzing ground water quality data in light of the stated monitoring objective. The suggested approach accounts for "natural" variation in background water quality through pairing of observations. The limitations of quarterly sampling for detecting small changes in quality over a short time frame are discussed. 相似文献
58.
Truman Bennett 《Ground water》1982,20(4):390-392
59.
60.
Allen P. Nutman Vickie C. Bennett Clark R. L. Friend Kenji Horie Hiroshi Hidaka 《Contributions to Mineralogy and Petrology》2007,154(4):385-408
The Eoarchaean (>3,600 Ma) Itsaq Gneiss Complex of southern West Greenland is dominated by polyphase orthogneisses with a
complex Archaean tectonothermal history. Some of the orthogneisses have c. 3,850 Ma zircons, and they vary from rare single
phase metatonalites to more common complexly banded migmatites. This is due to heterogeneous strain, in situ anatexis and
granitic veining superimposed during younger tectonothermal events. In the single-phase tonalites with c. 3,850 Ma zircon,
oscillatory-zoned prismatic zircon is all 3,850 Ma old, but shows patchy ancient loss of radiogenic Pb. SHRIMP spot analyses
and laser ablation ICP-MS depth profiling show that thin (usually < 10 μm) younger (3,660–3,590 Ma and Neoarchaean) shells
of lower Th/U metamorphic zircon are present on these 3,850 Ma zircons. Several samples with this simple zircon population
occur on islands near Akilia. In contrast, migmatites usually contain more complex zircon populations, with often more than
one generation of igneous zircon present. Additional zircon dating of banded gneisses across the Complex shows that samples
with c. 3,850 Ma igneous zircon are not just a phenomenon restricted to Akilia and adjacent islands. For example, migmatites
from Itilleq (c. 65 km from Akilia) contain variable amounts of oscillatory-zoned 3,850 Ma and 3,650 Ma zircon, interpreted,
respectively, as the rock age and the time of crustal melting under Eoarchaean metamorphism. With only 110–140 ppm Zr in the
tonalites and likely magmatic temperatures of >850°C, zircon solubility–melt composition relationships show that they were
only one-third saturated in zircon. Any zircon entrained in the precursor magmas would thus have been highly soluble. Combined
with the cathodoluminesence imaging, this demonstrates that the c. 3,850 Ma oscillatory zoned zircon crystallised out of the
melt and hence gives a magmatic age. Thus the rare well-preserved tonalites and palaeosome in migmatites testify that c. 3,850 Ma
quartzo–feldspathic rocks are a widespread (but probably minor) component in the Itsaq Gneiss Complex. C. 3,850 Ma zircon
with negative Eu anomalies (showing growth in felsic systems) also occurs as detrital grains in rare c. 3,800 Ma metaquartzites
and as inherited grains in some 3,660 Ma granites (sensu stricto). These demonstrate that still more c. 3,850 Ma rocks were present, but were recycled into Eoarchaean sediments and crustally
derived granites. The major and trace element characteristics (e.g. LREE enrichment, HREE depletion, low MgO) of the best-preserved
c. 3,850 Ma rocks are typical of Archaean TTG suites, and thus argue for crust formation processes involving important contributions
from melting of hydrated mafic crust to the earliest Archaean. Five c. 3,850 Ma tonalites were selected as the best preserved
on the basis of field criteria and zircon petrology. Four of these samples have overlapping initial ɛNd (3,850 Ma) values from +2.9 to +3.6± 0.5, with the fourth having a slightly lower value of +0.6. These data provide additional
evidence for a markedly LREE-depleted early terrestrial mantle reservoir. The role of c. 3,850 Ma crust should be considered
in interpreting isotope signatures of the younger (3,800–3,600 Ma) rocks of the Itsaq Gneiss Complex.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献