What is the relationship between food shopping and daily mobility? A relational approach to analysis of food access     

Jerry Shannon  W. Jay Christian 《GeoJournal》2017,82(4):769-785

Recent research on food access has increasingly focused on how individuals’ daily mobility, much of it based on activity spaces created from GPS data. In this paper, we expand this research through an analysis of a large transit survey (n = 21,298 households) from Minneapolis/St. Paul, Minnesota. We do this using relational approach focused on the topological connections found in household travel patterns rather than measures of exposure based on geographic distance. Our exploratory data analysis analyzes both grocery shopping and eating out across the metropolitan area, focusing on the position of utilized food sources relative to home and work locations, utilized modes of transit, and other daily activities often combined with food shopping. Households often used food sources located outside their residential neighborhoods, usually moving toward the central city to do so. Eating out occurred farther from home than grocery shopping, though in many cases close to work. Automobile use was most common for grocery shopping trips, but less so in the lowest income households and in the central city. Our findings show that a relational approach can identify distinctive patterns in everyday food provisioning by emphasizing the connections between food shopping and other everyday household activities.  相似文献   

Silicon Deficiency Induces Alkaline Phosphatase Enzyme Activity in Cultures of Four Marine Diatoms     

Soledad Fuentes  Gary H. Wikfors  Shannon Meseck 《Estuaries and Coasts》2014,37(2):312-324

Alkaline phosphatase (AP) was detected using ELF-97® in silicon-starved Pseudo-nitzschia multiseries cells; thus, we tested two, alternative hypotheses: Pseudo-nitzschia multiseries has a high phosphate demand, showing signs of phosphate deficiency even when concentrations of orthophosphate are high, or silicate deficiency can stimulate the AP enzyme in this species. We also studied the effect of silicon deficiency on AP in three other common marine diatoms: Thalassiosira pseudonana, Nitzschia pusilla, and Nitschia closterium. Each of the species tested showed a different pattern of AP regulation. AP levels, however, increased in the four diatoms as a result of silicon deficiency, suggesting that AP may be involved in a variety of intracellular processes related to silicon deficiency. Additionally, the results of this study indicate that AP could be stimulated by stressors other than phosphate deficiency, such as silicon deficiency; therefore, it should be used cautiously as an indicator of phosphate limitation.  相似文献   

Z     

Shannon J.P. McPherron  Harold L. Dibble  Paul Goldberg 《Geoarchaeology》2005,20(3):243-262

Paleolithic archaeologists have been recording the three‐dimensional coordinates of excavated artifacts for several decades. These data, however, have been put to limited use. Z, or absolute elevation, in particular, is seldom used in analysis despite the fact that it speaks most directly to one of the more important areas of research we have—namely, behavioral change through time. This article addresses this deficiency in two ways. First, it examines the way in which we record elevations. The point is made that the elevations returned by high‐resolution recording systems like total stations provide behavioral and site formation data that traditional recording systems are probably incapable of capturing. Second, elevation data from two Middle Paleolithic sites are used to examine changes in behavioral factors that structure the archaeological record and that apparently take place independent of changes in factors which structure the geological record. © 2005 Wiley Periodicals, Inc.  相似文献   

New Tools for Assessing Reactive Mineral-Mediated Abiotic Contaminant Transformation     

John Horst  Craig Divine  Jennifer Tilton  Shandra Justicia-León  Shannon Ulrich  Robert J. Stuetzle 《Ground Water Monitoring & Remediation》2019,39(2):12-21

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The Case for Flux‐Based Remedial Performance Monitoring Programs          下载免费PDF全文

Allan Horneman  Craig Divine  Theresa Sandtangelo‐Dreiling  Shannon Lloyd  Hunter Anderson  Michael B. Smith  John McCray 《Ground Water Monitoring & Remediation》2017,37(3):16-18

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The source of raw materials for Roman pottery from Leptiminus,Tunisia     

Barbara L. Sherriff  Patricia Court  Shannon Johnston  Lea Stirling 《Geoarchaeology》2002,17(8):835-861

Leptiminus, a Roman port city on the west coast of Tunisia, North Africa, exported olive oil and a garum fish paste to Rome. Excavations have uncovered many facilities including kilns and a potter's workshop, indicating an extensive ceramic industry. The vessels, manufactured at Leptiminus, included African red‐slip fineware, coarseware, and amphorae. A petrographic study of pottery sherds showed them to contain very similar temper, rounded aeolian sand grains and limestone, but varying in proportions to produce different textures. An investigation of the source of raw materials for the pottery found three distinct types of clay within a 50 km radius of Leptiminus: grey Miocene, brown Pliocene, and green Late Pliocene clay. Statistical analysis of trace element compositions, using induced neutron activation, of clays and sherds showed that the Pliocene brown clay was used to create all types of pottery. The specific clay horizon, used in Roman times, has apparently been removed by quarrying. However, a lateral continuation of this bed was found 7 m beneath the Leptiminus site 290. © 2002 Wiley Periodicals, Inc.  相似文献   

Evaluating post-hurricane impacts in co-management areas: a framework for expert consensus     

Diaz  John  Carnevale  Shannon  Millett  Cheryl  Abd-Elrahman  Amr  Britt  Katie 《Natural Hazards》2020,103(2):1905-1916

Natural Hazards - Natural ecosystems are characterized as dynamic systems that evolve through natural patterns of disturbance. Land managers can work within this system of natural disturbance by...  相似文献   

High-resolution X-ray fluorescence profiling of hybrid event beds: Implications for sediment gravity flow behaviour and deposit structure     

Arif Hussain  Peter D. W. Haughton  Patrick M. Shannon  Jonathan N. Turner  Colm S. Pierce  Arnau Obradors-Latre  Simon P. Barker  Ole J. Martinsen 《Sedimentology》2020,67(6):2850-2882

Hybrid event beds form when turbidity currents that transport or locally acquire significant quantities of mud decelerate. The mud dampens turbulence driving flow transformations, allowing both mud and sand to settle into dense, near-bed fluid layers and debris flows. Quantifying details of the mud distribution vertically in what are often complex tiered deposits is critical to reconstructing flow processes and explaining the diverse bed types left by mud-bearing gravity flows. High-resolution X-ray fluorescence core scanning provides continuous vertical compositional profiles that can help to constrain mud distribution at sub-millimetre scale, offering a significant improvement over discrete sampling. The approach is applied here to cores acquired from the Pennsylvanian Ross Sandstone Formation, western Ireland, where a range of hybrid event beds have been identified. Raw X-ray fluorescence counts are calibrated against element concentrations and mineral abundances determined on coincident core plugs, with element and element log-ratios used as proxies to track vertical changes in abundances of quartz, illite (including mica), chlorite and calcite cement. New insights include ‘stepped’ (to higher values) as opposed to ‘saw-tooth’ vertical changes in mud content and the presence of compositional banding that would otherwise be overlooked. Hybrid event beds in basin floor sheets that arrived ahead of the prograding fan system have significantly cleaner sandy components than those in mid-fan lobes. The latter may imply that the heads of the currents emerging from mid-fan channels entrained significant mud immediately before they collapsed. Many of the H3 debrites are bipartite with a sandier H3a division attributed to re-entrainment and mixing of a trailing debris or fluid mud flow (H3b) with sand left by the forward part of the flow. Hybrid event bed structure may thus partly reflect substrate interaction and mixing during deposition, and the texture of the bed divisions may not simply mirror those in the suspensions from which they formed.  相似文献   

Desolate landscapes: Ice‐Age settlement in Eastern Europe     

Shannon P. McPherron 《Geoarchaeology》2003,18(8):904-905

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