This paper summarizes a strategy for supplying ecosystem services in urban areas through a participatory planning process targeting multifunctional green infrastructure. We draw from the literature ...on landscape multifunctionality, which has primarily been applied to agricultural settings, and propose opportunities to develop urban green infrastructure that could contribute to the sustainable social and ecological health of the city. Thinking in terms of system resilience, strategies might focus on the potential for green infrastructure to allow for adaptation and even transformation in the face of future challenges such as climate change, food insecurity, and limited resources. Because planning for multiple functions can be difficult when many diverse stakeholders are involved, we explored decision support tools that could be applied to green infrastructure planning in the early stages, to engage the public and encourage action toward implementing a preferred solution. Several specific ecosystem services that could be relevant for evaluating current and future urban green spaces include: plant biodiversity, food production, microclimate control, soil infiltration, carbon sequestration, visual quality, recreation, and social capital. Integrating such ecosystem services into small-scale greening projects could allow for creativity and local empowerment that would inspire broader transformation of green infrastructure at the city level. Those cities committing to such an approach by supporting greening projects are likely to benefit in the long run through the value of ecosystem services for urban residents and the broader public.
In the United States, interest in urban agriculture has grown dramatically. While community gardens have sprouted across the landscape, home food gardens—arguably an ever-present, more durable form ...of urban agriculture—have been overlooked, understudied, and unsupported by government agencies, non-governmental organizations, and academics. In part a response to the invisibility of home gardens, this paper is a manifesto for their study in the Global North. It seeks to develop a multi-scalar and multidisciplinary research framework that acknowledges the garden’s social and ecological or material dimensions. Given the lack of existing research, we draw on the more extensive literature on home gardens in the South and community gardens in the North to develop a set of hypotheses about the social-ecological effects of urban home food gardens in the North. These gardens, we hypothesize, contribute to food security, community development, cultural reproduction, and resilience at multiple scales; conserve agrobiodiversity; and support urban biodiversity. They may also have negative ecological effects, such as stormwater nutrient loading. Because of the entanglement of the social and the ecological or material in the garden, we review three theoretical perspectives—social ecological systems theory, actor-network theory, and assemblage theory—that have been or could be applied to the multi-scalar and multidisciplinary study of the garden. We also review sampling and analytic methods for conducting home garden research. The paper concludes with a discussion of opportunities to extend the research agenda beyond descriptive analysis, the primary focus of garden research to date.
► Extraction of urban agriculture sites from Google Earth images is highly accurate. ► Urban agriculture is an extensive land use type in Chicago. ► Much of the production area has been previously ...undocumented. ► A small percentage of Chicago sites reported to be community gardens produce food. ► Home gardens constitute the majority of existing food production area in Chicago.
Although always a part of city life, urban agriculture has recently attracted increased attention from diverse groups in the United States, which promote it as a strategy for stimulating economic development, increasing food security and access, and combatting obesity and diabetes, among other goals. Developing effective policies and programs at the city or neighborhood level demands as a first step the accurate mapping of existing urban agriculture sites. Mapping efforts in major U.S. cities have been limited in their focus and methodology. Focusing on public sites of food production, such as community gardens, they have overlooked the actual and potential contribution of private spaces, including home food gardens, to local food systems. This paper describes a case study of urban agriculture in Chicago which used the manual analysis of high-resolution aerial images in Google Earth in conjunction with ArcGIS to identify and map public and private spaces of food production. The resulting spatial dataset demonstrates that urban agriculture is an extensive land use type with wide variations in the distribution of sites across the city. Only 13% of sites reported to be community gardening projects by nongovernment organizations and government agencies were determined, through image analysis, to be sites of food production. The production area of home gardens identified by the study is almost threefold that of community gardens. Study results suggest opportunities may exist for scaling up existing production networks—including home food gardens—and enhancing community food sovereignty by leveraging local knowledges of urban agriculture.
The onset of phytoplankton blooms in late winter, early spring has been traditionally associated with the shoaling of the mixed layer above a critical depth. Here we show that the onset of a bloom ...can also be triggered by a reduction in air–sea fluxes at the end of winter. When net cooling subsides at the end of winter, turbulent mixing becomes weak, thereby increasing the residence time of phytoplankton cells in the euphotic layer and allowing a bloom to develop. The necessary change in the air–sea flux generally precedes mixed-layer shoaling, and may provide a better indicator for the onset of the spring bloom than the mixed-layer depth alone. Our hypothesis is supported by numerical simulations and remote sensing data.
Abstract
The influence of submesoscale currents on the distribution and subduction of passive, buoyant tracers in the mixed layer is examined using large-eddy simulations. Submesoscale eddies are ...generated through an ageostrophic baroclinic instability associated with a background horizontal buoyancy gradient. The simulations also include various levels of surface cooling, which provides an additional source of three-dimensional turbulence. Submesoscales compete against turbulent convection and restratify the mixed layer while generating strong turbulence along a submesoscale front. Buoyant tracers accumulate at the surface along the submesoscale front where they are subducted down into the water column. The presence of submesoscales strongly modifies the vertical tracer flux, even in the presence of strong convective forcing. The correlation between high tracer concentration and strong downwelling enhances the vertical diffusivity for buoyant tracers.
Bacteria play an indispensable role in marine biogeochemistry by recycling dissolved organic matter. Motile species can exploit small, ephemeral solute patches through chemotaxis and thereby gain a ...fitness advantage over nonmotile competitors. This competition occurs in a turbulent environment yet turbulence is generally considered inconsequential for bacterial uptake. In contrast, we show that turbulence affects uptake by stirring nutrient patches into networks of thin filaments that motile bacteria can readily exploit. We find that chemotactic motility is subject to a trade-off between the uptake benefit due to chemotaxis and the cost of locomotion, resulting in an optimal swimming speed. A second trade-off results from the competing effects of stirring and mixing and leads to the prediction that chemotaxis is optimally favored at intermediate turbulence intensities.
Medicinally relevant spirocyclic indolenines, carbazoles and quinolines can each be directly synthesised selectively from common indolyl ynone starting materials by catalyst variation. The high ...yielding, divergent reactions all proceed by an initial dearomatising spirocyclisation reaction to generate an intermediate vinyl–metal species, which then rearranges selectively by careful choice of catalyst and reaction conditions.
Medicinally relevant spirocyclic indolenines, carbazoles and quinolines can each be directly synthesised selectively from common indolyl ynone starting materials by catalyst variation (see scheme). The high yielding, divergent reactions all proceed by an initial dearomatising spirocyclisation reaction to generate an intermediate vinyl–metal species, which then rearranges selectively by careful choice of catalyst and reaction conditions.
Significant research effort has been devoted to the study and realization of autonomous wireless systems for wireless sensor and personal-area networking, the internet of things, and ...machine-to-machine communications. Low-power RF integrated circuits, an energy harvester and a power management circuit are fundamental elements of these systems. An FM-UWB Transceiver for Autonomous Wireless Systems presents state-of-the-art developments in low-power FM-UWB transceiver realizations. The design, performance and implementation of prototype transceivers in CMOS technology are presented. A working hardware realization of an autonomous node that includes a prototype power management circuit is also proposed and detailed in this book.Technical topics include: Low-complexity FM-UWB modulation schemesLow-power FM-UWB transceiver prototypes in CMOS technologyCMOS on-chip digital calibration techniquesSolar power harvester and power management in CMOS for low-power RF circuitsAn FM-UWB Transceiver for Autonomous Wireless Systems is an ideal text and reference for engineers working in wireless communication industries, as well as academic staff and graduate students engaged in electrical engineering and communication systems research.
Statement of problem Computer-aided technology is an emerging method for fabricating complete dentures. Consolidated information about historical background, current status, and scope for the future ...is lacking. Purpose The purpose of this systematic review was to analyze the existing literature on computer-aided technology for fabricating complete dentures and provide the reader with a historical background, current status, and future perspectives on this emerging technology. Material and methods An electronic search of the English language literature between the periods of January 1957 and June 2012 was performed by using PubMed/MEDLINE with the following specific search terms: CAD-CAM complete dentures, digital complete dentures, computer dentures, designed dentures, machined dentures, manufactured dentures, milled dentures, and rapid prototyping dentures. Additionally, the search terms were used on the Google search engine to identify current commercial manufacturers and their protocols. Results A total of 1584 English language titles were obtained from the electronic database, and the systematic application of exclusion criteria resulted in the identification of 8 articles pertaining to computer-aided technology for complete dentures. Since the first published report in 1994, multiple authors have described different theoretical models and protocols for fabricating complete dentures with computer-aided technology. Although no clinical trials or clinical reports were identified in the scientific literature, the Google search engine identified 2 commercial manufacturers in the United States currently fabricating complete dentures with computer-aided design and computer-aided manufacturing (CAD/CAM) technology for clinicians world-wide. These manufacturers have definitive protocols in place and offer exclusive dental materials, techniques, and laboratory support. Their protocols contrast with conventional paradigms for fabricating complete dentures and allow the fabrication of complete dentures in 2 clinical appointments. Conclusions A body of scientific literature related to computer-aided technology for complete dentures is emerging. Significant advancements in this technology have now resulted in their commercial availability with shorter clinical protocols. However, prospective clinical trials with true clinical endpoints are necessary to validate this technology. This could affect dental education, patient care, research, and public health worldwide.
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