Belonging in charlotte: multiscalar differences in local immigration politics and policies          下载免费PDF全文

Owen Furuseth  Heather Smith  Paul Mcdaniel 《Geographical review》2015,105(1):1-19

In the context of Charlotte, North Carolina's, emergence as a “globalizing” pre‐emergent immigrant gateway, this paper focuses on a complex and multiscalar set of governmental policies and community‐development dynamics that are shaping localized response to Hispanic/Latino immigration. Specifically, we explore how these policies and dynamics play out spatially in the context of two Charlotte neighborhoods, both of which have similar historical roots and have become magnets for Latino settlement, yet display divergent contemporary place‐making paths. Our exploration reveals the ways in which contexts of receptivity and spaces of both exclusion and inclusion are created by the socio‐spatial components of public policy and the localized response to that policy at the intraurban level. Reinforcing the importance of space and place in the construction of receptivity contexts, the compared stories of Eastside and South Charlotte reveal that neighborhoods are never the product of one transformational force but of many—no matter how they may be perceived in the public imaginary.  相似文献   

The Impact Of Extreme Summer Melt on Net Accumulation of an Avalanche Fed Glacier,as Determined by Ground‐Penetrating Radar          下载免费PDF全文

Heather Purdie  Wolfgang Rack  Brian Anderson  Tim Kerr  Trevor Chinn  Ian Owens  Matthew Linton 《Geografiska Annaler: Series A, Physical Geography》2015,97(4):779-791

Glacier mass balance is more sensitive to warming than cooling, but feedbacks related to the exposure of previously buried firn and ice in very warm years is not generally considered in sensitivity studies. A ground‐penetrating radar survey in the accumulation area of Rolleston Glacier, New Zealand shows that five years of previous net accumulation was removed by melt from parts of the glacier above the long‐term equilibrium line altitude during a single negative mass balance year. Rolleston Glacier receives a large amount of accumulation from snow avalanches, which may temporarily buffer it from climate warming by providing additional mass that has accumulated at higher elevations, effectively increasing the elevation range of the glacier. However, glaciers reliant on avalanche input may have high sensitivity to climatic variations because the extra mass is concentrated on a small part of the glacier, and small variations in avalanche input could have a large impact on overall glacier accumulation. Further research is needed to better estimate the amount and spatial distribution of accumulation by avalanche in order to quantify the climate sensitivity of small avalanche‐fed glaciers.  相似文献   

Regionalization of heavy rainfall to improve climatic design values for infrastructure: case study in Southern Ontario,Canada     

Edson Paixao  Heather Auld  M. Monirul Qader Mirza  Joan Klaassen  Mark W. Shephard 《水文科学杂志》2013,58(7):1067-1089

Abstract

Southern Ontario, Canada, has been impacted in recent years by many heavy rainfall and flooding events that have exceeded existing historical estimates of infrastructure design rainfall intensity–duration–frequency (IDF) values. These recent events and the limited number of short-duration recording raingauges have prompted the need to research the climatology of heavy rainfall events within the study area, review the existing design IDF methodologies, and evaluate alternative approaches to traditional point-based heavy rainfall IDF curves, such as regional IDF design values. The use of additional data and the regional frequency analysis methodology were explored for the study area, with the objective of validating identified clusters or homogeneous regions of extreme rainfall amounts through Ward's method. As the results illustrate, nine homogeneous regions were identified in Southern Ontario using the annual maximum series (AMS) for daily and 24-h rainfall data from climate and rate-of-rainfall or tipping bucket raingauge (TBRG) stations, respectively. In most cases, the generalized extreme value and logistic distributions were identified as the statistical distributions that provide the best fit for the 24-h and sub-daily rainfall data in the study area. A connection was observed between extreme rainfall variability, temporal scale of heavy rainfall events and location of each homogeneous region. Moreover, the analysis indicated that scaling factors cannot be used reliably to estimate sub-daily and sub-hourly values from 24- and 1-h data in Southern Ontario.

Citation Paixao, E., Auld, H., Mirza, M.M.Q., Klaassen, J. & Shephard, M.W. (2011) Regionalization of heavy rainfall to improve climatic design values for infrastructure: case study in Southern Ontario, Canada. Hydrol. Sci. J. 56(7), 1067–1089.  相似文献   

Perception of the rip current hazard on Galveston Island and North Padre Island,Texas, USA   总被引：1，自引：1，他引：0  

Christian Brannstrom  Sarah Trimble  Anna Santos  Heather Lee Brown  Chris Houser 《Natural Hazards》2014,72(2):1123-1138

The hazard posed by a rip current depends in part on the ability of beach users to identify a rip current and to associate surf conditions with the potential for rip currents. Understanding which visual features beach users associated with rip currents is an important step in the development of appropriate programs and educational materials aimed at improving the ability of beach users to identify a rip current. A face-to-face survey (n = 392) was conducted to assess the ability of beach users to identify a rip current using five near eye-level photographs that simulate the view of the beach and surf zone as the respondent approached the beach. The survey was conducted on three heavily used public beaches in Texas (Galveston, Port Aransas, and Corpus Christi) at the height of the summer beach season in 2012. Only 13 % of respondents correctly selected the photograph showing the most hazardous conditions and correctly identified the precise location of the rip current on the photograph. The majority of beach users (87 %) incorrectly indicated that the photograph with the heaviest surf represented the most hazardous surf conditions and greatest potential for the development of rip currents, or failed to identify rip currents in photographs. Respondents who were able to correctly identify the rip current tended to recognize the breaking wave pattern, areas of darker water, or the proximity to structures as key visual characteristics of rip currents and also had higher self-reported abilities to swim in rough water and escape a rip current.  相似文献   

The role of non-nation-state actors and side events in the international climate negotiations     

Heike Schroeder  Heather Lovell 《Climate Policy》2013,13(1):23-37

United Nations climate change conferences have attracted an increasing number and range of observer participants, often outnumbering national delegates. The interactions between the formal and informal spaces of climate governance at the Conference of the Parties (COP) are explored by investigating why non-nation state actors (NNSAs) attend them and by measuring to what extent official UN Side Events provide relevant information for the formal negotiations. Based on primary empirical research at recent COPs, it is found that 60–75% of Side Events have related directly to items under negotiation in the post-2012 climate negotiations. In this regard, Side Events that facilitate informal exchange between stakeholders not only provide input into the negotiations but also allow issues beyond the realm of the negotiations to be discussed, reflecting the scope of climate change. Although Side Events are an effective forum to exchange ideas and network, their current format and purpose as being events ‘on the side’ does not offer a sufficient framework for coordination between the work of NNSAs and the United Nations Framework Convention on Climate Change (UNFCCC) process.  相似文献   

The new enclosure: the appropriation of public land in neoliberal Britain     

Heather Whiteside 《Urban geography》2013,34(7):1062-1064

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Complex internal architecture of a debris‐flow deposit revealed using ground‐penetrating radar,Cass, New Zealand     

Colette C.A. Starheim  Christopher Gomez  Justin Harrison  Claire Kain  Nicholas J. Brewer  Kirsty Owen  Danang Sri Hadmoko  Heather Purdie  Peyman Zawar‐Reza  Ian Owens  Patrick Wassmer  Franck Lavigne 《New Zealand geographer》2013,69(1):26-38

Previous research on debris‐flow deposit structure typically reports little to no visually discernible stratigraphy. The preliminary findings presented here provide evidence for more complex internal deposit architecture with inverse grading and subunits thought to reflect individual flow surges. Ground‐penetrating radar surveys, geospatial data and field observations are used to describe 10 subunits traceable over the 14 lateral radargrams imaging the lower 38 m of the deposit. Additional subunits are depicted further upslope in a longitudinal transect. As well as demonstrating the need for continued investigation of deposit architecture using non‐traditional techniques, these results may help improve future interpretations of post‐event deposits.  相似文献   

Processes affecting geochemistry and contaminant movement in the middle Claiborne aquifer of the Mississippi embayment aquifer system     

Brian G. Katz  James A. Kingsbury  Heather L. Welch  Roland W. Tollett 《Environmental Earth Sciences》2012,65(6):1759-1780

Groundwater chemistry and tracer-based age data were used to assess contaminant movement and geochemical processes in the middle Claiborne aquifer (MCA) of the Mississippi embayment aquifer system. Water samples were collected from 30 drinking-water wells (mostly domestic and public supply) and analyzed for nutrients, major ions, pesticides, volatile organic compounds (VOCs), and transient age tracers (chlorofluorocarbons, tritium and helium-3, and sulfur hexafluoride). Redox conditions are highly variable throughout the MCA. However, mostly oxic groundwater with low dissolved solids is more vulnerable to nitrate contamination in the outcrop areas east of the Mississippi River in Mississippi and west Tennessee than in mostly anoxic groundwater in downgradient areas in western parts of the study area. Groundwater in the outcrop area was relatively young (apparent age of less than 40 years) with significantly (p < 0.05) higher dissolved oxygen and nitrate–N concentrations and higher detections of pesticides and VOCs compared to water samples from wells in downgradient areas. Oxygen reduction and denitrification rates were low compared to other aquifers in the United States (zero order rate constants for oxygen reduction and denitrification were 4.7 and 5–10 μmol/L/year, respectively). Elevated concentrations of nitrate–N, and detections of pesticides and VOCs in some deep public supply wells (>50 m depth) indicated contaminant movement from shallow parts of the aquifer into deeper oxic zones. Given the persistence of nitrate in young oxic groundwater that was recharged several decades ago, and the lack of a confining unit, the downward movement of young contaminated water may result in higher nitrate concentrations over time in deeper parts of the aquifer containing older oxic water.  相似文献   

Long-term shoreline retreat rates on Whidbey Island,Washington, USA     

Heather E. Rogers  Terry W. Swanson  John O. Stone 《Quaternary Research》2012,78(2):315-322

Long-term retreat rates of Puget Sound's unconsolidated sediment shorelines have been difficult to quantify, and little systematic research has been completed to constrain retreat in this area. We put forward a new application of cosmogenic ¹⁰Be exposure dating to assess long-term shoreline retreat on Whidbey Island, WA by dating lag boulders exposed on the shore platform as the shoreline erodes. Production of ¹⁰Be in shoreline boulders is modulated by both tidal submergence and topographic shielding from the retreating bluff. By modeling the combined effect of these variables on ¹⁰Be production, the timing of exposure can be determined and used to calculate long-term (10³–10⁴ yr) bluff retreat rates. In rare cases, retreat rates are underestimated due to inherited ¹⁰Be. Within the study area, average retreat rates ranged between 0 and 8 cm yr^? 1. Our results demonstrate the utility of cosmogenic nuclides for determining long-term shoreline retreat rates in areas with thick sediment cover, where large numbers of samples can be collected, and where the pre-depositional history of the boulders is uncomplicated.  相似文献   

Degassing of Cl, F, Li, and Be during extrusion and crystallization of the rhyolite dome at Volcán Chaitén, Chile during 2008 and 2009     

Jacob B. Lowenstern  Heather Bleick  Jorge A. Vazquez  Jonathan M. Castro  Peter B. Larson 《Bulletin of Volcanology》2012,74(10):2303-2319

We investigated the distribution of Cl, F, Li, and Be in pumices, obsidians, and crystallized dome rocks at Chaitén volcano in 2008?C2009 in order to explore the behavior of these elements during explosive and effusive volcanic activity. Electron and ion microprobe analyses of matrix and inclusion glasses from pumice, obsidian, and microlite-rich dome rock indicate that Cl and other elements were lost primarily during crystallization of the rhyolitic dome after it had approached the surface. Glass in pumice and microlite-free obsidian has 888?±?121?ppm Cl, whereas residual glass in evolved microlite-rich dome rock generally retains less Cl (as low as <100?ppm). Estimated Cl losses were likely >0.7?Mt Cl, with a potential maximum of 1.8?Mt for the entire 0.8-km³ dome. Elemental variations reflect an integrated bulk distribution ratio for Cl?>?1.7 (1.7 times more Cl was degassed or incorporated into crystals than remained in the melt). Because Cl is lost dominantly as the very last H₂O is degassed, and Cl is minimally (if at all) partitioned into microlites, the integrated vapor/melt distribution ratio for Cl exceeds 200 (200 times more Cl in the evolved vapor than in the melt). Cl is likely lost as HCl, which is readily partitioned into magmatic vapor at low pressure. Cl loss is accelerated by the change in the composition of the residual melt due to microlite growth. Cl loss also may be affected by open-system gas fluxing. Integrated vapor-melt distribution ratios for Li, F, and Be all exceed 1,000. On degassing, an unknown fraction of these volatiles could be immediately dissolved in rainwater.  相似文献