Problem, research strategy, and findings: Big box stores have proliferated across the United States in the last three decades. Proponents have praised them for providing affordability and convenience to consumers, but opponents have criticized them for driving out local businesses, among other negative impacts for communities. We examine the impact of a big box store on a traditional downtown for the case of Davis (CA), which amended its zoning code to allow a Target store that opened at the periphery of the city in 2009. We use a before-and-after survey to determine where residents shopped for selected items before the store opened and after, evaluating which businesses were most affected. The results show that the new big box store had a limited impact on downtown businesses but substantial impact on stores located elsewhere within Davis and especially beyond city limits.
Takeaway for practice: The Davis case suggests that the impacts of big box stores are not always what opponents anticipate. Other cities may lack some of the natural advantages that helped downtown Davis survive the opening of a big box store, but our results suggest that deliberate efforts to protect and enliven the downtown area mattered, too. Planners who want to fortify their own downtowns from the potential harms of big box stores could focus on enhancing downtown vitality by supporting a wide variety of activities and promoting the experiential aspects of shopping downtown. Such strategies would also put downtowns in a better position for surviving the rapidly evolving terrain of retail industry in the 21st century. 相似文献
Problem, research strategy, and findings: To understand how communities use zoning ordinances to achieve sustainability goals, we identify nine sustainability principles and 53 associated regulatory items that might be included in a zoning ordinance to achieve sustainable development and then examine the zoning ordinances of 32 randomly selected communities to determine if they included these principles and their associated items. We find both wide variation and some consistency in how zoning ordinances address sustainability goals, independent of city size or location in the country. Some of the identified principles and regulatory items are found in many ordinances; others appear in only a few. However, there is an inverse relationship between the age of the ordinance and the extent to which it includes sustainability principles. As ordinances are updated, it is likely that they will address more topical sustainability concerns. We study only ordinance content, not implementation; moreover, sustainability can be achieved in ways other than zoning. However, zoning ordinances that directly address sustainability in many dimensions are more likely to achieve these goals. We conclude that planners can more effectively use zoning ordinances to achieve sustainable development.Takeaway for practice: This review of zoning ordinances can alert local planners to the many ways in which zoning ordinances could be used to achieve sustainability goals and suggest how planners can assess the contribution of their zoning ordinance to the sustainable development of their communities. 相似文献
Samples were collected from 407 fin whales, Balaenoptera physalus, at four North Atlantic and one Mediterranean Sea summer feeding area as well as the Sea of Cortez in the Pacific Ocean. For each sample, the sex, the sequence of the first 288 nucleotides of the mitochondrial (mt) control region and the genotype at six microsatellite loci were determined. A significant degree of divergence was detected at all nuclear and mt loci between North Atlantic/Mediterranean Sea and the Sea of Cortez. However, the divergence time estimated from the mt sequences was substantially lower than the time elapsed since the rise of the Panama Isthmus, suggesting occasional gene flow between the North Pacific and North Atlantic ocean after the separation of the two oceans. Within the North Atlantic and Mediterranean Sea, significant levels of heterogeneity were observed in the mtDNA between the Mediterranean Sea, the eastern (Spain) and the western (the Gulf of Maine and the Gulf of St Lawrence) North Atlantic. Samples collected off West Greenland and Iceland could not be unequivocally assigned to either of the two areas. The homogeneity tests performed using the nuclear data revealed significant levels of divergence only between the Mediterranean Sea and the Gulf of St Lawrence or West Greenland. In conclusion, our results suggest the existence of several recently diverged populations in the North Atlantic and Mediterranean Sea, possibly with some limited gene flow between adjacent populations, a population structure which is consistent with earlier population models proposed by Kellogg, Ingebrigtsen, and Sergeant. 相似文献
European Journal of Wood and Wood Products - Laccase-treated wood fibres were tested for small-scale wet-process manufacture of hardboards. Two laccases of distinct redox potentials, one from... 相似文献
The solution structure of oxidized cytochrome c(553) (71 amino acid residues) from the Gram-positive bacterium Bacillus pasteurii is here reported and compared with the available crystal structure. The solution structure is obtained from 1609 meaningful NOE data (22.7 per residue), 76 dihedral angles, and 59 pseudocontact shifts. The root mean square deviations from the average structure are 0.25+/-0.07 and 0.59+/-0.13 A for the backbone and all heavy atoms, respectively, and the quality assessment of the structure is satisfactory. The solution structure closely reproduces the fold observed in the crystal structure. The backbone mobility was then investigated through amide (15)N relaxation rate and (15)N-(1)H NOE measurements. The protein is rigid in both the sub-nanosecond and millisecond time scales, probably due to the relatively large heme:number of amino acids ratio. Modeling of eight c-type cytochromes from other Gram-positive bacteria with a high sequence identity (>30 %) to the present cytochrome c(553) was performed. Analysis of consensus features accounts for the relatively low reduction potential as being due to extensive heme hydration and indicates residues 34-35, 44-46, 69-72, and 75 as a conserved hydrophobic patch for the interaction with a protein partner. At variance with mitochondrial c-type cytochrome, this protein does not experience pH-dependent coordination equilibria. The reasons for this difference are analyzed. 相似文献
Growth traits represent a main goal in aquaculture breeding programs and may be related to adaptive variation in wild fisheries. Integrating quantitative trait loci (QTL) mapping and next generation sequencing can greatly help to identify variation in candidate genes, which can result in marker-assisted selection and better genetic structure information. Turbot is a commercially important flatfish in Europe and China, with available genomic information on QTLs and genome mapping. Muscle and liver RNA-seq from 18 individuals was carried out to obtain gene sequences and markers functionally related to growth, resulting in a total of 20,447 genes and 85,344 single nucleotide polymorphisms (SNPs). Many growth-related genes and SNPs were identified and placed in the turbot genome and genetic map to explore their co-localization with growth-QTL markers. Forty-five SNPs on growth-related genes were selected based on QTL co-localization and relevant function for growth traits. Forty-three SNPs were technically feasible and validated in a wild Atlantic population, where 91% were polymorphic. The integration of functional and structural genomic resources in turbot provides a practical approach for QTL mining in this species. Validated SNPs represent a useful set of growth-related gene markers for future association, functional and population studies in this flatfish species. 相似文献
Problem, research strategy, and findings: There are more than 400 U.S. metropolitan planning organizations (MPOs) overseeing multiple transportation projects totaling billions of dollars, yet these crucial organizations and their history and current role are generally unknown or confusing to many planning practitioners and scholars. MPOs face major challenges in developing meaningful long-range regional transportation plans, challenges rooted in their history that planners should understand as they grapple with metropolitan planning efforts. MPOs may approve projects and their funding, but disparate agencies and often competitive local governments control budgets and actually build projects. MPOs, moreover, do not fully represent all regional interests and have no control over the local land use decisions that would support less autocentric communities and human-powered modes. I provide a metareview of the history of regional transportation planning and the MPOs responsible for it, describing U.S. metropolitan transportation planning from the early 20th century. Federal legislation in the 1960s first suggested a regional forum for conversations about metropolitan transportation. Federal legislation in subsequent decades made incremental if incomplete progress toward creating a meaningful regional forum, adapting institutions and practices to increase stakeholder involvement as well as the scope of transport planning, yet MPOs have multiple limitations that planners can address.
Takeaway for practice: History suggests that MPOs can be a force for regional change. Planners and policymakers could anchor future reforms to MPOs’ existing legal and administrative frameworks. Planners should revisit the membership and voting structures of MPO boards to ensure better stakeholder representation and permit some MPOs to generate and direct transportation funds at the local level. 相似文献
Psychologists are taking the lead to ensure that consumers have full access to behavioral science knowledge in America's hospitals. This article recaps the development of psychology's position in hospitals and explores the variety of current and prospective roles of psychologists in inpatient health care. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献