Acoustic observations of the swimming behavior of the euphausiid Euphausia pacifica Hansen     

De Robertis  Alex; Schell  Chad; Jaffe  Jules S 《ICES Journal of Marine Science》2003,60(4):885-898

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Trawl hangs, baby fish, and closed areas: a win-win scenario     

Link  Jason S; Demarest  Chad 《ICES Journal of Marine Science》2003,60(5):930-938

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Placing the “Analyst” in Discourse Analysis: Iteration,Emergence and Dialogicality as Situated Process     

Chad N. Steacy  Brian S. Williams  Christian L. Pettersen  Hilda E. Kurtz 《The Professional geographer》2016,68(1):166-173

Discourse analysis is a powerful and versatile methodological tool, informing a diverse body of critical geographic scholarship. Too often, however, discourse analysis remains unexplored, operating as a “black box,” underelaborated and hence undertheorized as to just what it offers. In this article, we articulate discourse analysis as inherently processual, by which we mean both that it should be understood as a process and that it can play an integral role throughout the research process. This article is derived from a meta-analysis of an exercise that invited early-career geographers to conduct discourse analysis on commentary centered on the 2013 U.S. federal government shutdown. The reflexive research process highlights the iterative, emergent, and dialogic properties of a processual engagement with a text. We suggest that recognizing these qualities enriches the role of both the analysis and the analyst(s) and expands the valence of discourse analysis as a productive and versatile component of critical human geography.  相似文献   

Diatom assemblage response to Iroquoian and Euro-Canadian eutrophication of Crawford Lake,Ontario, Canada   总被引：2，自引：0，他引：2  

Erik J. Ekdahl  Jane L. Teranes  Chad A. Wittkop  Eugene F. Stoermer  Euan D. Reavie  John P. Smol 《Journal of Paleolimnology》2007,37(2):233-246

Diatom and geochemical data from Crawford Lake, Ontario, have been used to document limnological responses to periods of cultural disturbance resulting from native Iroquoian occupation of the watershed (1268–1486 AD) and Euro-Canadian agriculture and deforestation (1867 AD–present). Here, we further develop the high-resolution nature of the Crawford Lake sediment record to examine the physical, chemical and biological aspects of limnological response to human disturbances in the lake catchment area with exceptional detail. We report detailed diatom abundance and flux data for individual taxa from Crawford Lake, and further describe the relationship between assemblage composition and environmental conditions using canonical correspondence analysis (CCA). Diatom assemblage data are used to calculate diatom inferred-total phosphorus (DI-TP) concentrations for the past ∼1,000 years. We also examine the diatom community response during and after periods of disturbance by Iroquoian and Euro-Canadian populations, and compare this response to existing geochemical proxies of lake production and new elemental geochemical indicators of catchment area erosion. In particular, we explore the differing limnological response to the two distinct periods of cultural eutrophication and examine the limnological processes that occurred during the period of␣low (or no) human activity (1487–1866 AD), when geochemical indicators of lake production recovered to pre-disturbance conditions, but diatom assemblages notably did not. Our results illustrate the highly susceptible nature of diatom communities to periods of anthropogenic disturbance, and emphasize that ecological indicators (such as diatom assemblages) should be included with other proxies (such as nutrient concentrations and physical characteristics) when assessing disturbance and recovery in lake systems.  相似文献   

Corrigendum     

Chad W. Higgins  Marc B. Parlange  C. Meneveau 《Boundary-Layer Meteorology》2004,110(3):479-479

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The substorm current wedge and midnight sector partial ring current near substorm onset: A synthesis based on a magnetotail magnetic field geometry model     

George J Sofko  Kathryn A McWilliams  Chad R Bryant 《极地研究(英文版)》2013,24(1)

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Assessing a decade of phosphorus management in the Lake Mendota, Wisconsin watershed and scenarios for enhanced phosphorus management     

Emily L. Kara  Chad Heimerl  Tess Killpack  Matthew C. Van de Bogert  Hiroko Yoshida  Stephen R. Carpenter 《Aquatic Sciences - Research Across Boundaries》2012,74(2):241-253

A phosphorus (P) budget was estimated for the watershed of Lake Mendota, Wisconsin, to assess the effects of nutrient management on P accumulation in the watershed soils. We estimated how nutrient management programs and legislation have affected the budget by comparing the budget for 2007 to a budget calculated for 1995, prior to implementation of the programs. Since 1995, inputs decreased from 1,310,000 to 853,000 kg P/yr (35% reduction) and accumulation decreased from 575,000 to 279,000 kg P/yr (51% reduction). Changes in P input and accumulation were attributed primarily to enhanced agricultural nutrient management, reduction in dairy cattle feed supplements and an urban P fertilizer ban. Four scenarios were investigated to determine potential impacts of additional nutrient management tactics on the watershed P budget and P loading to Lake Mendota. Elimination of chemical P fertilizer input has the greatest potential to reduce watershed P accumulation and establishment of riparian buffers has the greatest potential to prevent P loading to Lake Mendota.  相似文献   

A short-term predictive system for surface currents from a rapidly deployed coastal HF radar network     

Donald Barrick  Vicente Fernandez  Maria I. Ferrer  Chad Whelan  Øyvind Breivik 《Ocean Dynamics》2012,62(5):725-740

In order to address the need for surface trajectory forecasts following deployment of coastal HF radar systems during emergency-response situations (e.g., search and rescue, oil spill), a short-term predictive system (STPS) based on only a few hours data background is presented. First, open-modal analysis (OMA) coefficients are fitted to 1-D surface currents from all available radar stations at each time interval. OMA has the effect of applying a spatial low-pass filter to the data, fills gaps, and can extend coverage to areas where radial vectors are available from a single radar only. Then, a set of temporal modes is fitted to the time series of OMA coefficients, typically over a short 12-h trailing period. These modes include tidal and inertial harmonics, as well as constant and linear trends. This temporal model is the STPS basis for producing up to a 12-h current vector forecast from which a trajectory forecast can be derived. We show results of this method applied to data gathered during the September 2010 rapid-response demonstration in northern Norway. Forecasted coefficients, currents, and trajectories are compared with the same measured quantities, and statistics of skill are assessed employing 16 24-h data sets. Forecasted and measured kinetic variances of the OMA coefficients typically agreed to within 10–15%. In one case where errors were larger, strong wind changes are suspected and examined as the cause. Sudden wind variability is not included properly within the STPS attack we presently employ and will be a subject for future improvement.  相似文献   

Geographic Polarization,Partisan Voting,And The Battle Over Same‐Sex Marriage Within The Culture War     

Chad J Kinsella  Colleen McTague  Kevin Raleigh 《Geographical review》2019,109(2):224-248

Geographic polarization arises when partisan, or like‐minded, voters live in enclaves separate from voters of differing partisan behavior. Research studies at multiple scales of analysis suggest that geographic polarization most typically occurs regarding partisan voting behavior; however, few studies have analyzed polarization with a focus on policy preferences. This research examines same‐sex marriage policy through two statewide issues that shared the presidential election ballot in 2004. The results of that presidential election and these two ballot initiatives are examined in Cincinnati, Ohio, and counties in its surrounding Metropolitan Statistical Area (MSA) in both Ohio and Kentucky. A geographically polarized relationship was found between partisan results and same‐sex marriage results. In addition, the findings suggest that despite a close link between partisan voting and issue voting on same‐sex marriage, spatial clustering (geographic polarization) was identified of those who voted differently from their fellow partisans.  相似文献   

Comparison of bulk and compound-specific δC analyses and determination of carbon sources to salt marsh sediments using n-alkane distributions (Maine,USA)     

Benjamin R. Tanner  Maria E. Uhle  Claudia I. Mora  Joseph T. Kelley  Patrick J. Schuneman  Chad S. Lane  Evan S. Allen 《Estuarine, Coastal and Shelf Science》2010

Sources of sedimentary organic matter to a Morse River, Maine (USA) salt marsh over the last 3390 ± 60 RCYBP (Radiocarbon Years Before Present) are determined using distribution patterns of n-alkanes, bulk carbon isotopic analysis, and compound-specific carbon isotopic analysis. Marsh foraminiferal counts suggest a ubiquitous presence of high marsh and higher-high marsh deposits (dominated by Trochammina macrescens forma macrescens, Trochammina comprimata, and Trochammina inflata), implying deposition from ∼0.2 m to 0.5 m above mean high water. Distributions of n-alkanes show a primary contribution from higher plants, confirmed by an average chain length value of 27.5 for the core sediments, and carbon preference index values all >3. Many sample depths are dominated by the C₂₅ alkane. Salicornia depressa and Ruppia maritima have similar n-alkane distributions to many of the salt marsh sediments, and we suggest that one or both of these plants is either an important source to the biomass of the marsh through time, or that another unidentified higher plant source is contributing heavily to the sediment pool. Bacterial degradation or algal inputs to the marsh sediments appear to be minor. Compound-specific carbon isotopic analyses of the C₂₇ alkane are on average 7.2‰ depleted relative to bulk values, but the two records are strongly correlated (R² = 0.89), suggesting that marsh plants dominate the bulk carbon isotopic signal. Our study underscores the importance of using caution when applying mixing models of plant species to salt marsh sediments, especially when relatively few plants are included in the model.  相似文献