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31.
The shell of the adult Ceratostoma foliatum (Gmelin) is characterized by three varices with foliations, and a tooth on the anterior portion of the outer lip. These features are derived gradually from the markedly different sculpture of shells of small juveniles (a network of fine axial and spiral cords). The sculpture changes as the thin, cord-like basic varix is elaborated, reinforced, and modified by the development of a secondary structure (the tooth) and as the number of varices per whorl decreases. Most muricid shell patterns can be derived from juvenile patterns similar to that of C. foliatum by quantitative variations in these four processes. Likely functions of the complex and varied muricid shell structures include stabilization in shifting substrates, defense against predators, and strengthening of the shell. Different functions and shell-growth patterns are likely for the different types of varices. Shell structures are most elaborate on shells of adults. A structure's functions are likely to change as the structure becomes more complex on each successive whorl. The functional period in an individual's lifespan is consequently restricted by the pattern of growth, the rate of structural development, and the rate of shell erosion.  相似文献   
32.
Determination of polycyclic aromatic hydrocarbons (PAHs) from chemical analysis of the diesel particulate matter (DPM) requires considerable sampling expertise and is often time-consuming because sample preparation demands strict extraction procedures due to the complex nature of the DPM matrix. In this study, a method to measure the emissions of the 16-U.S. Environmental Protection Agency (EPA) priority PAHs adsorbed in diesel particles has been developed. This method involves the capture of the DPM in glass microfibre filters, thermal extraction of the compounds from the particulate matrix in a thermogravimetric analyzer (TGA), determination of the concentration by means of a solid phase micro-extraction (SPME) fibre and subsequent analysis using a gas chromatograph coupled to a mass spectrometer (GC/MS). Analyses of a fully characterised DPM prepared by the National Institute of Standards and Technology, NIST (SRM 1650b), were performed and calculated errors showed that the method is capable of giving reliable quantitative data. Additionally, DPM collected from a diesel engine was analyzed and the results showed the high method sensitivity to the engine operating conditions.  相似文献   
33.
The rocky subtidal community off the Atlantic coast of Nova Scotia has historically undergone a cyclical transition between Laminaria-dominated kelp beds and sea urchin-dominated barrens. Since the introduction of the invasive alga Codium fragile ssp. tomentosoides, a third community state has emerged: Codium-dominated algal beds. We conducted a 42-week feeding experiment in the laboratory, which mimicked the quantity and quality of food available to urchins (Strongylocentrotus droebachiensis) in each of these community states. Feeding rate, growth, reproduction, and survival of urchins fed either Laminaria longicruris or C. fragile ad libidum, or L. longicruris 2 days per month, were measured. Although the ad libidum feeding rate on C. fragile was higher than that on kelp, energy intake was lower. Urchins in the ad libidum kelp treatment were larger and had larger gonads than those in the C. fragile treatment. Urchins fed kelp infrequently exhibited little somatic and gonadic growth over the course of the experiment. Regression analysis revealed that urchin performance on these diets was strongly related to energy intake. Diet treatment had no effect on survival or gonad maturation. Although urchins can consume substantial amounts of C. fragile, it appears that they cannot, or do not, feed quickly enough to compensate for its lower nutritional value. Our results suggest that, although urchins feeding on C. fragile are capable of surviving, growing, and reproducing, the replacement of kelp by C. fragile in some areas might negatively affect urchin populations as they continue to repopulate the shallow subtidal zone.  相似文献   
34.
WinMISKAM is evaluated from an emergency response perspective. Comparisons are made between ground level concentrations observed during selected Mock Urban Setting Test (MUST) field trials and predictions generated by the model. The model was driven by 5 min averaged on-site meteorological data, and used minimum grid spacing of 0.5 m in both the horizontal and vertical. The code was found to perform well, with 46% of all predictions (paired in time and space) and 83% of arc maxima predictions within a factor of two of observed concentrations. The model was found to perform better for neutral cases than stable cases with 27% of stable case predictions and 57% of neutral case predictions within a factor of two when compared in time and space.  相似文献   
35.
Identity management refers to the decisions individuals make about how they present their social identities to others. We examined cross‐cultural differences in distancing and affirming identity management strategies of Christian‐identified employees utilizing samples from the USA and South Korea. Religious centrality, risks of disclosure, pressure to assimilate to organizational norms, and nation were key antecedents of chosen identity management strategies. Risks of disclosure and pressure to assimilate related to more distancing and less affirming strategies when religious centrality was low, but nation served as a boundary condition for the moderating effects of religious centrality. Distancing strategies related to negative outcomes regardless of religious centrality, but affirming strategies only related to positive outcomes when religious centrality was low. We discuss how this work contributes to theoretical and practical understanding of identity management in the workplace and across cultures. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
36.
湖泊富营养化的程度日益严重,已经对人类的生产生活、水生动植物的生存造成了危害。西方一些发达国家尤其是美国已经制定了水体水质基准,形成了一系列的基准制定的方法体系,建立了水质的管理体制。文章描述了我国的湖泊富营养化的现状、美国营养物基准的研究进展;列举了几个能够辅助基准制定的数学模型,探讨了我国的湖泊富营养化基准的制定方法步骤;通过几种模型的比较,并结合我国各方面的特点,确定我国基准制定中参照状态向基准的转化方法以及基准模型的应用和成果。  相似文献   
37.
38.
In this study, three different soils with contrasting features, spiked with 300 mg benzo[a]pyrene (BaP)/kg dry soil, were incubated at 20 °C and 60% water holding capacity for 540 days. At different time points, BaP and DNA were extracted and quantified, and DNA adducts were quantified by 32P-postlabelling. After 540 days incubation, 69.3, 81.6 and 83.2% of initial BaP added remained in Cruden Bay, Boyndie and Insch soils, respectively. Meanwhile, a significantly different amount of DNA-BaP adducts were found in the three soils exposed to BaP over time. The work demonstrates the concept that DNA adducts can be detected on DNA extracted from soil. Results suggest the technique is not able to directly reflect bioavailability of BaP transformation products. However, this new method provides a potential way to detect mutagenic compounds in contaminated soil and to assess the outcomes of soil remediation.  相似文献   
39.
Faith-based organizations (FBOs) have played a significant role in environment-related forms of development and governance in Melanesia, including the Solomon Islands. Yet despite their centrality, there remain significant gaps in understandings of processes and outcomes associated with FBO engagement in environment-related development interventions. This paper addresses this gap by analysing the place of the Christian Fellowship Church (CFC), an indigenous FBO active in plantation forestry (and other activities) in the Western Province in the Solomon Islands. We find that the CFC possesses impressive income-generating potential and political networks; however this does not always translate into positive social, economic or environmental outcomes at the village level. While FBOs such as CFC are often championed as playing an important role in environmental governance in an under-resourced nation state, the reality is that they can fall well short in delivering appropriate outcomes for poor communities or the environment despite, and because of, their close ties to target communities.  相似文献   
40.
This article brings to light one aspect of alternative agri-food practices by exploring the values and meanings domestic food producers associate with their actions, thereby making a small contribution to increasing understanding of the act of urban backyard food production. While Australian backyards have long been productive spaces, there has been little examination of this phenomenon in the Australian context. Limited quantitative data give some insight into the extent of domestic production, and while there is an increasing interest in certain aspects of the local food system, including community gardens and farmers markets, there is a dearth of literature that explores the contemporary act of domestic production. This work seeks to situate the act of domestic production within the broader movement calling for change within the global food system, particularly that being articulated by the food sovereignty movement. Drawing on Gibson–Graham's diverse economies framework, and through interviews with eight domestic food producers in one Australian city, this work finds that the act of growing food at home offers space for hope – where small acts can be seen as part of the broader food sovereignty movement seeking to remake our food system.  相似文献   
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