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451.
452.
The structure of the spermatozoa of 11 species from five families of archaeogastropod (Haliotidae, Fissurellidae, Trochidae, Turbinidae, Phasianellidae) has been examined using transmission electron microscopy. All sperm are of the primitive, or ect-aquasperm type and each species has a sperm head (nucleus and acrosome) with unique morphology. Furthermore, the results from the present study together with those published in the literature reveal that, although there are a few exceptions, the size (length to breadth ratio) and spape of the nucleus and acrosome of sperm of species within each family are similar. It is therefore possible to identify members of a family and differentiate between families using sperm morphology. The intrafamilial similarities and interfamilial differences in sperm structure indicate that a spermiocladistic study of the suborder Vetigastropoda could provide interesting insights into the phylogenetic relationships of this group.  相似文献   
453.
454.
Public opposition to the siting of waste facilities has been partly explained by a failure to directly involve communities in fundamental policy decisions about waste management. Public participation at the local level is primarily reactive, based upon the premise of consultation on preferred strategies rather than direct involvement in their derivation. This paper presents the findings of a study into the effectiveness of a more proactive community involvement programme adopted by one English county council. The paper suggests some opportunities and barriers to public involvement in waste management strategy development and the potential effectiveness of consensus-building approaches.  相似文献   
455.
Seven pumice samples from excavations in North Sinai have been investigated with respect to their geochemical composition. This type of volcanic rock has been used as an abrasive and thus has been an object of trade since antiquity. With the help of Instrumental Neutron Activation Analysis, six of these Bronze Age samples could be correlated to their volcanic sources on the islands of Santorini, Nisyros and Giali (Greece) using the typical element concentrations (“chemical fingerprint”). The source of one pumice sample remains unidentified excluding, however, the Santorini eruption as a possible source. The concluding section of this article discusses the possible contribution, however indirect, of the pumice from Sinai and elsewhere in the Eastern Mediterranean to the controversial issue of the accurate date of the “Minoan” eruption of Santorini.  相似文献   
456.
To support decision making on complex environmental issues, models are often used to explore the potential impacts of different management alternatives on the environmental system. We explored how different model outcomes affect decision making. Two topics have our particular interest, namely (1) the influence of quantification of qualitative information on decision making, and (2) the influence of reflecting uncertainty in the model outcomes on decision making. We set up a survey, in which we use a case study describing a decision making situation in strategic river management. The survey was disseminated through the Internet. From the results we conclude that the quantification of information in itself does not necessarily change preferences, although the outcomes suggest that preferences converge when based on quantified information. When confronted with uncertainty information, respondents show a preference for the alternative with the smallest chance of negative impacts. The study shows that, whereas the modelling community often strives to provide the policy process with as good, and as detailed information as is possible, their assumption that this will automatically lead to ‘better’ decision making is not self-evident.  相似文献   
457.
Thermochemical biomass gasification, followed by conversion of the produced syngas to fuels and electrical power, is a promising energy alternative. Real-world characterization of particulate matter (PM) and other contaminants in the syngas is important to minimize damage and ensure efficient operation of the engines it powers and the fuels created from it. A dilution sampling system is demonstrated to quantify PM in syngas generated from two gasification plants utilizing different biomass feedstocks: a BioMax?15 Biopower System that uses raw and torrefied woodchips as feedstocks, and an integrated biorefinery (IBR) that uses rice hulls and woodchips as feedstocks. PM2.5 mass concentrations in syngas from the IBR downstream of the purification system were 12.8–13.7 μg·m−3, which were significantly lower than the maximum level for catalyst protection (500 μg·m−3) and were 2–3 orders of magnitude lower than those in BioMax?15 syngas (2247–4835 μg·m−3). Ultrafine particle number concentration and PM2.5 chemical constituents were also much lower in the IBR syngas than in the BioMax?15. The dilution sampling system enabled reliable measurements over a wide range of concentrations: the use of high sensitivity instruments allowed measurement at very low concentrations (∼1 μg·m−3), while the flexibility of dilution minimized sampling problems that are commonly encountered due to high levels of tars in raw syngas (∼1 g·m−3).  相似文献   
458.
This study investigates the influence of genetic factors on survey response behavior. A pool of 558 male and 500 female twin pairs from the Minnesota Twin Registry (MTR) was asked to complete a paper‐and‐pencil survey of leadership activities. We used quantitative genetics techniques to estimate the genetic, shared environmental, and nonshared environmental effects on people's compliance with the request for survey participation. Results indicated that genetic influences explained 45% of the variance in survey response behavior for both women and men, with little shared environmental effects. Similar estimates were obtained after we partialled out potential confounds including twin closeness, age, and education. The results have important implications for response rates and nonresponse bias in survey‐based research. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
459.
Abstract

This paper examines controversy during the 2001 foot-and-mouth outbreak after mass carcass burial sites were selected at two sites in northeast England, and focuses on shortcomings in public consultation surrounding the carcass disposal policy. The slaughter of six million animals necessitated a national disposal strategy on a hitherto unknown scale. The belated decision to concentrate carcass disposal in a small number of mass burial sites provoked more opposition in the two ex-mining localities selected in the northeast than anywhere else. In both cases local liaison committees were established to manage dialogue between residents and public authorities. We argue that, although seen by the authorities primarily as a vehicle for risk communication and public reassurance, for residents these functioned chiefly as a vehicle for holding public authorities to account. These divergent purposes were overshadowed by the chaotic circumstances in which the early stages of the mass burial policy were implemented, and the way in which the carcass disposal policy was dictated by the operation of the slaughter policy, whose draconian form precluded any but the most cursory public consultation.  相似文献   
460.
Arsenobetaine(AB) and thio-arsenoribosides were measured in common macroalgae species(8 phaeophyta, 4 rhodophyta and 2 chlorphyta), along the Australian south east coast line. As well, arsenic species profiles were measured for two common marine herbivores, the sea urchin Centrostephanus rodgersii and the fish Odax cyanomelas that graze on these macroalgae to understand if trophic transfer of these species would account for their presence in marine herbivores. AB was found in seven of the fourteen macroalgae species investigated but does not contributed significantly to any of the macroalgae arsenic content(0.01-1.2 μg/g). AB was found in only two of the brown macroalgae and all the red and green macroalgae(with the exception of Corallina officinalis). Thio-arsenic species were found sporadically, but not in high concentrations in any of the macroalgae investigated.AB present in macroalgae is likely to be associated with epiphytic organisms while thio-arsenoribosides are likely to be produced by decaying parts of damaged macroalgae.A laboratory feeding experiment in which the herbivorous gastropod, Austrocochlea constricta, was fed macroalgae containing thio-arsenoribosides for a 24 hr period every three days showed that these are readily accumulated over a short period. Thio-arsenoribosides in herbivores are therefore probably obtained through trophic transfer. Some AB is also obtained through trophic transfer; however, the presence of trimethylated arsonioribosides,a hypothesized precursor of AB formation in herbivores, suggests that some AB is produced within herbivores from the transformation of arsenoribosides accumulated from their diet.  相似文献   
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