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991.
Two basic and competing approaches for measuring the benefits of pollution abatement have found support in the recent literature-the property value approach and the health damage function approach. The purpose of this paper is to show that conditions will often exist when the property value approach will not accurately measure all benefits and conditions will always be present that cause the health damage function approach to underestimate benefits. In general, neither approach can stand alone. It is possible, however, that the two approaches can be combined in such a way as to improve the measurement of abatement benefits. We present an approach for combining these two methods and do so by introducing an “information coefficient” that measures the degree of knowledge about pollution effects held by the public. Approaches to estimating the information coefficient are suggested.  相似文献   
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We investigated mycosporine amino acid (MAA) involvement as protective sunscreens in spawn of the sea hare Aplysia dactylomela to determine if adult diet and ultraviolet (UV) exposure affected the UV sensitivity of developing embryos. Adults were fed a red alga rich in MAAs (Acanthophora spicifera) or a green alga poor in MAAs (Ulva lactuca). Adults on each diet were exposed for 2 wk to ambient solar irradiance with two types of acrylic filters; one allowed exposure to wavelengths >275 nm (designated UV) and one to wavelengths only >410 nm (designated NOUV). Spawn from each adult group was likewise treated with UV or NOUV and monitored during development for differences in mortality and metabolic rate (measured as oxygen consumption: O2). Also recorded were number of eggs or embryos per capsule, times to hatching, hatching success, size at hatching, and O2 of adults. Spawn from adults eating red algae was almost twice as rich in MAAs as spawn from adults eating green algae, suggesting that MAA content is diet-related. Although overall quantities of MAAs in the spawn reflected MAA contents of the adult diet, specific MAAs were differentially sequestered in the spawn. Thus, porphyra-334, found in high concentration in Aplysia dactylomela's preferred red algal food, was present in only low concentration in the spawn. Conversely, mycosporine-glycine, in low concentration in red algal food, was the most abundant MAA in the spawn. UV treatment of adults had no effect on quantities of MAAs in the spawn. Adults exposed to UV had significantly higher O2s and spawned twice as often. The UV-treated adults produced spawn with significantly higher O2s and their embryos developed to hatching sooner. The only significant effect of UV exposure of the spawn was to reduce the percentage of veligers hatching from 71 to 50%. There was no significant effect on hatching time or size of the veligers at hatching, nor on number of eggs per capsule. Received: 13 May 1997 / Accepted: 27 June 1997  相似文献   
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