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A number of different pretreatment and extraction procedures were compared with regard to recovery of PCDD/PCDF from fly ash. Highest results were obtained using an acid digestion with excess dilute HCl, followed by freeze drying of the residue and hot extraction by toluene. 相似文献
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Summary The Dominican Republic and other Caribbean countries face serious challenges to their natural resource base. In recent years
the government of the Dominican Republic has taken major steps toward the development and implementation of a comprehensive
plan for national natural resources management. This plan is called Plan Sierra. An important component of this plan is the
outline of actions for carrying out an environmental education programme within the country. This demonstrates a commitment
to fulfill Recommendation No. 96 of the Stockholm Conference in a way that could become a model for other Latin American nations.
Clinton L. Shepard is Assistant Professor in the Division of Environmental Education, School of Natural Resources, The Ohio
State University. Dr Shepard holds a Bachelor of Science degree in Zoology from the University of Kentucky and graduate degrees
from The Ohio State University in Natural Resources/Environmental Education and Education-Foundations and Research. He has
worked as an interpreter and Environmental Education Coordinator for the State of Ohio Department of Natural Resources, a
research associate for ERIC—Science, Math, and Environmental Education Clearinghouse, and College instructor in interpretive
methods, environmental education methodology, resident outdoor programming, and natural resources development. He is also
involved in international research and development, especially in the Caribbean Basin.
Robert E. Roth is Chairman/Professor in the Division of Environmental Education, School of Natural Resources, The Ohio State
University. Dr Roth received a Bachelor's degree in Wildlife Management, a Bachelor's degree in Secondary Science Education,
a Master's degree in Conservation Education from The Ohio State University, and his Ph.D. in Environmental Education from
The University of Wisconsin. he came to OSU in 1969 and since that time has designed and institutionalized the only academic
unit in the US that offers both well developed undergraduate and graduate programmes in Environmental Communications, Education
and Interpretation and has published over 40 works in the field. He has been instrumental in implementing a growing international
environmental education research and development emphasis in the wider Caribbean, he continues as an Executive Editor of theJournal of Environmental Education. 相似文献
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P.M. Roth S.D. Reynolds T.W. Tesche P.D. Gutfreund C. Seigneur 《Environment international》1983,9(6):549-571
The purpose of this study is to evaluate the effect of reductions of reactive organic gases (ROG) and NOx emissions on short-term O3 and NO2 concentrations and annual average NO2 concentrations in the California South Coast Air Basin. Short-term air quality predictions were obtained by applying the Systems Applications Airshed Model to summer O3 and autumn NO2 episodes. Effects of emission controls on annual NO2 concentrations were estimated using CDM and a new parcel tracking model NOXTRAK. Results for the summer O3 episode indicate that ROG emission reduction in an effective means for reducing peak O3 concentrations. NOx emission reduction imposed in addition to ROG emission reductions are counterproductive in reducing peak O3 concentrations. The modeling results also suggest that attainment of the 1-h federal O3 standard requires ROG emission reductions on the order of 80% from 1987 levels. Results for the autumn NO2 episode indicate that NOx emission reductions approximating those recommended in a proposed Air Quality Management Plan (about 22%) will result in only small (about 5%) reductions in the peak NO2 concentrations. ROG emission reduction may be more effective than NOx emission reduction in reducing the peak NO2 concentration. For the episode studied, a reduction of 36% in ROG emissions is estimated to result in a reduction in peak NO2 concentrations commensurate with that required to attain the 1-h state NO2 standard. Model calculations also indicate that the federal NO2 standard may not be meet by 1987 at one or two stations, but may blosely approached. 相似文献
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The relationship between various experimental concentrations of CO2 and calcification in Bossiella orbigniana (Decaisne) was studied by measuring Ca-45 incorporation into the crystalline matrix. Air containing CO2 at partial pressures (PCO
2) of 0.04 to 5.5% was bubbled through synthetic seawater in incubation vessels. The resultant pH values in the presence of plants ranged from 6.5 to 8.7. The maximum calcification rate appears to lie between 0.11 and 1.05% PCO
2. The data suggest that calcification is controlled by a biological process that may be sensitive to pH and/or to the relative bicarbonate concentration. The data also suggest that a severalfold increase in CO2 over the present atmospheric level might lead to increased calcification in this marine alga. 相似文献
20.
Mixed-species associations have been described in many vertebrate species, but few behavioral studies have investigated associations
between species from different mammalian orders. Cape ground squirrels (Xerus inauris) are highly social rodents that inhabit burrows with two species of mongoose, but the benefits of these interspecific associations
to ground squirrels remain unresolved. We compared the behavior of squirrels while solitary, with conspecifics, and in the
presence of suricates (Suricata suricatta) and yellow mongooses (Cynictis pencillatus). Squirrels spent less time alert and more time feeding when suricates were present, but increased vigilance in the presence
of yellow mongooses. In a series of mobbing trials with a puff adder (Bitis arietans), a common predator of all three species, Cape ground squirrels were the most active in mobbing the snake. Our results suggest
that Cape ground squirrels benefit from associating with suricates, but not necessarily with yellow mongooses. Both mongoose
species benefit from the burrowing activities of the squirrels for thermoregulation and escape from predators, and a suite
of other organisms may similarly benefit from the habitat modifications by Cape ground squirrels, suggesting they could be
considered ecosystem engineers of the arid and semi-arid regions of southern Africa. Thus, the association between Cape ground
squirrels and suricates appears mutually beneficial, whereas yellow mongooses may merely be commensals of the squirrels. 相似文献