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New Scholarship from UNCW Faculty
This page is designed to showcase the newest research being published by UNCW faculty. You can subscribe to the "New Scholarship from UNCW Faculty" RSS feed.
Which eResources are included?eResources currently included in these search results are: Web of Science, PubMed, ScienceDirect, PsycInfo, EconLit, BIOSIS Previews, Film & Television Literature Index, Communication and Mass Media Complete, Historical Abstract, SPORTDiscus, Zoological Record, and the Library Catalog. How is this list created?It is created from an aggregation of search result RSS feeds from research databases to which Randall Library subscribes.
These search results were crafted by librarians to search for author affiliation information.
The end product is a "master" feed that represents a large percentage of the scholarly output of UNCW faculty. Is this list comprehensive?No, it is not everything published by UNCW faculty.
It relies on the research being indexed by one of the included eResources, as well as some type of author affiliation to UNCW being provided in the citation indexing.
You may also notice duplicate titles, as some journals are indexed in more than one eResource.
Skeletal growth in early and late Neolithic foragers from the Cis-Baikal region of Eastern Siberia.
Am J Phys Anthropol. 2013 Nov 22;
Authors: Temple DH, Bazaliiskii VI, Goriunova OI, Weber AW
Skeletal growth is explored between Early Neolithic (EN) (8000 to 6800 BP) and Late Neolithic (LN) (6000 to 5200 BP) foragers from the Cis-Baikal region of Eastern Siberia. Previous studies suggest that increased systemic stress and smaller adult body size characterize the EN compared to LN. On this basis, greater evidence for stunting and wasting is expected in the EN compared to LN. Skeletal growth parameters assessed here include femoral and tibial lengths, estimated stature and body mass, femoral midshaft cortical thickness, total bone thickness, and medullary width. Forward selection was used to fit polynomial lines to each skeletal growth parameter relative to dental age in the pooled samples, and standardized residuals were compared between groups using t tests. Standardized residuals of body mass and femoral length were significantly lower in the EN compared to LN sample, particularly from late infancy through early adolescence. However, no significant differences in the standardized residuals for cortical thickness, medullary width, total bone thickness, tibial length, or stature were found between the groups. Age ranges for stunting in femoral length and wasting in body mass are consistent with environmental perturbations experienced at the cessation of breast feeding and general resource insecurity in the EN compared to LN sample. Differences in relative femoral but not tibial length may be associated with age-specific variation in growth-acceleration for the distal and proximal limb segments. Similarity in cortical bone growth between the two samples may reflect the combined influences of systemic and mechanical factors on this parameter. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.
PMID: 24264164 [PubMed - as supplied by publisher]
Publication date: Available online 27 November 2013
Author(s): R.J. Kieber , S. Tatum , J.D. Willey , G.B. Avery , R.N. Mead
Ethanol and acetaldehyde concentrations were measured in 52 rain events collected between January 25, 2011 and March 4, 2012 in Wilmington, North Carolina, USA.Ethanol concentrations ranged from 23 nM to 908 nM with a volume weighted average concentration of 192 ±20 nM while acetaldehyde ranged from 23 nM to 909 nM with a volume weighted average concentration of 193 ± 25 nM. There was a great deal of variability in the abundance of ethanol and acetaldehyde between rain events driven primarily by temporal and air mass back trajectory influences. The ratio of ethanol to acetaldehyde was at a minimum during periods of peak solar intensity underscoring the importance of alcohol oxidation by a photochemically generated oxidant such as hydroxyl radical in the gas and/or aqueous phase. Ethanol and acetaldehyde concentrations were not strongly correlated with rain amount suggesting that gas-phase concentrations were not significantly depleted during the storm or that they were resupplied during the course of the rain event.The concentration of ethanol and acetaldehyde were correlated with nitrate and non-sea salt sulfate suggesting the importance of terrestrial and anthropogenic inputs at this location. Comparison of future ethanol and acetaldehyde concentrations in rainwater to the data presented in this study will help delineate potential consequences of these labile oxygenated volatile organic compounds (OVOCs) on the chemistry of the troposphere as the United States transitions to more ethanol blended fuels. Aqueous phase impacts of increasing ethanol concentrations will be particularly significant to the oxidizing capacity of atmospheric waters because of its reactivity with ∙OH and ∙HO2 radicals in solution.Increased rainwater concentrations could also have significant ramifications on receiving watersheds because of the biogeochemical lability of the alcohol.
A comparison of network, neighborhood, and node levels of analyses in two models of nitrogen cycling in the Cape Fear River Estuary
Publication date: Available online 1 December 2013
Author(s): David E. Hines , Stuart R. Borrett
Ecological network analysis is a set of algorithms that provide a holistic approach to the study of ecosystems. These analyses operate on at least three different hierarchical levels: network, neighborhood, and node. Network level analyses capture whole-system interactions and provide a broad view of the system; neighborhood level analyses provide relational information for specific parts or sub-networks; node level analyses offer descriptive characteristics of individual nodes. This work investigated the insights gained from each of these levels of analysis in an ecological network analysis case study. We compared two nitrogen cycling network models constructed at sites with different salinities, one oligohaline and one polyhaline, in the Cape Fear River Estuary, NC, USA as a case study to demonstrate the differences between levels of analysis. We evaluated the nitrogen cycling models at both the network and node levels, and compared these results to existing results of a neighborhood level analysis. We further compared the ecological implications of the nitrogen network comparison produced by each hierarchical level to test the null hypotheses that there would be no difference between the conclusions resulting from these levels of analysis. We found that while network level analyses showed little difference between the two nitrogen models, differences with potential ecological importance for the availability of nutrients to phytoplankton could be seen using node level analyses. The results of the existing neighborhood level analyses exhibited characteristics with similarities to the results of both the network and node level analyses. We show that higher hierarchical levels, which integrate the information contained at the lower levels, can mask potentially important signals when describing network attributes. Therefore, we conclude that ecosystem networks should be analyzed at multiple hierarchical levels to provide a complete description of system function.
Publication date: 1 February 2014
Source:Earth and Planetary Science Letters, Volume 387
Author(s): A. Rovere , M.E. Raymo , J.X. Mitrovica , P.J. Hearty , M.J. OʼLeary , J.D. Inglis
Determining eustatic sea level during the Mid-Pliocene warm period (∼3.3 to 2.9 Ma) has been a central but elusive goal in the study of past warm climates. Estimates of eustatic sea level based on geologic data span a broad range; variation that we now recognize is due in part to geographically varying post-depositional displacement caused by glacial isostatic adjustment and dynamic topography. In this study, we combine field observations and glacial isostatic adjustment modeling to estimate the dynamic topography signal in three areas that are important to paleo-sea level studies of the Mid-Pliocene warm period (South Africa, West Australia and southeastern United States). We show that dynamic topography played a significant role in the post-depositional displacement of Pliocene, and even younger Pleistocene, shorelines. In this regard, we provide a robust paleo-sea level elevation data set, corrected for glacial isostatic adjustment, that can be used to evaluate predictions from mantle flow models of dynamic topography.
Publication date: December 2013
Source:Animal Behaviour, Volume 86, Issue 6
Author(s): Stephanie J. Kamel , Richard K. Grosberg
Environmental implication of nitrogen isotopic composition in ornithogenic sediments from the Ross Sea region, East Antarctica: Δ15N as a new proxy for avian influence
Publication date: 10 January 2014
Source:Chemical Geology, Volume 363
Author(s): Yaguang Nie , Xiaodong Liu , Tao Wen , Liguang Sun , Steven D. Emslie
We analyzed δ15N in both acid-treated and untreated sediment profiles from McMurdo Sound of the Ross Sea region, East Antarctica that were influenced by penguin guano. The difference between treated and untreated δ15N (Δ15N) was significant in three profiles which were heavily impacted by guano, and minor in two profiles with less guano influence. We determined that the total nitrogen in the sediments is primarily derived from penguin guano and algae, and used an N-species test to explain the variation of Δ15N in two profiles. It was found that post-depositional decomposition and ammonia volatilization, which have important roles in the cold and arid environment of East Antarctica, would render an elevated δ15N through kinetic isotopic fractionation in the inorganic nitrogen from guano. N-species analysis revealed that the percentage of inorganic nitrogen in total nitrogen, indicative of the degree of guano influence, is the key factor controlling Δ15N in the sediments. This hypothesis successfully explained the nitrogen isotopic composition in the remaining three sediment profiles. We conclude that the parameter Δ15N, rather than traditionally used untreated δ15N, can be taken as an effective proxy for the strength of avian influence on ornithogenic sediments in East Antarctica.
Microcystins and two new micropeptin cyanopeptides produced by unprecedented Microcystis aeruginosa blooms in North Carolina's Cape Fear River
Publication date: January 2014
Source:Harmful Algae, Volume 31
Author(s): Justin D. Isaacs , Wendy K. Strangman , Amy E. Barbera , Michael A. Mallin , Matthew R. McIver , Jeffrey L.C. Wright
The Cape Fear River is the largest river system in North Carolina. It is heavily used as a source of drinking water for humans and livestock as well as a source of irrigation water for crops, and production water for industry. It also serves as a major fishery for both commercial and recreational use. In recent years, possibly related to increased eutrophication of the river, massive blooms of cyanobacteria, identified as Microcystis aeruginosa have been observed. Bloom samples collected in 2009 and 2012 were chemically analyzed to determine if they contained cyanobacterial toxins known as microcystins. Both blooms were found to produce microcystins in high yields. Microcystins are potent hepatotoxins that can be bio-accumulated in the food chain. Recent biological studies have also shown a host of other potentially harmful effects of low level microcystin exposure. Detailed chemical analysis of these blooms led us to discover that these blooms produce an additional family of cyanobacterial peptides know as the micropeptins, including two new members named micropeptins 1106 and 1120. The biological activities of these new molecules have not yet been determined, although protease activity has been well documented for this peptide group. These data indicate a need for thorough monitoring of toxin levels especially during bloom events in addition to additional biological testing of other cyanopeptides present in blooms.
Geomorphic characterization of four shelf-sourced submarine canyons along the U.S. Mid-Atlantic continental margin
Publication date: Available online 25 September 2013
Source:Deep Sea Research Part II: Topical Studies in Oceanography
Author(s): Jeffrey Obelcz , Daniel Brothers , Jason Chaytor , Uri ten Brink , Steve W. Ross , Sandra Brooke
Shelf-sourced submarine canyons are common features of continental margins and are fundamental to deep-sea sedimentary systems. Despite their geomorphic and geologic significance, relatively few passive margin shelf-breaching canyons worldwide have been mapped using modern geophysical methods. Between 2007 and 2012 a series of geophysical surveys was conducted across four major canyons of the US Mid-Atlantic margin: Wilmington, Baltimore, Washington, and Norfolk canyons. More than 5700km2 of high-resolution multibeam bathymetry and 890 line-km of sub-bottom CHIRP profiles were collected along the outer shelf and uppermost slope (depths of 80-1200m). The data allowed us to compare and contrast the fine-scale morphology of each canyon system. The canyons have marked differences in the morphology and orientation of canyon heads, steepness and density of sidewall gullies, and the character of the continental shelf surrounding canyon rims. Down-canyon axial profiles for Washington, Baltimore and Wilmington canyons have linear shapes, and each canyon thalweg exhibits morphological evidence for recent, relatively small-scale sediment transport. For example, Washington Canyon displays extremely steep wall gradients and contains ~100m wide, 5–10m deep, v-shaped incisions down the canyon axis, suggesting modern or recent sediment transport. In contrast, the convex axial thalweg profile, the absence of thalweg incision, and evidence for sediment infilling at the canyon head, suggest that depositional processes strongly influence Norfolk Canyon during the current sea-level high-stand. The north walls of Wilmington, Washington and Norfolk canyons are steeper than the south walls due to differential erosion, though the underlying cause for this asymmetry is not clear. Furthermore, we speculate that most of the geomorphic features observed within the canyons (e.g., terraces, tributary canyons, gullies, and hanging valleys) were formed during the Pleistocene, and show only subtle modification by Holocene processes active during the present sea-level high-stand.
The climate-population nexus in the East African Horn: Emerging degradation trends in rangeland and pastoral livelihood zones
Publication date: December 2013
Source:Global Environmental Change, Volume 23, Issue 6
Author(s): Narcisa G. Pricope , Gregory Husak , David Lopez-Carr , Christopher Funk , Joel Michaelsen
Increasing climate variability and extreme weather conditions along with declining trends in both rainfall and temperature represent major risk factors affecting agricultural production and food security in many regions of the world. The rangelands of Ethiopia, Kenya, and Somalia in the East African Horn remain one of the world's most food insecure regions, yet have substantially increasing human populations predominantly dependent on pastoralist and agro-pastoralist livelihoods. We identify regions where substantial rainfall decrease between two periods interrupted by the 1998 El Nino event (1981–2012) in the East African Horn is coupled with human population density increases. Vegetation in this region is characterized by a variable mosaic of land covers, generally dominated by grasslands necessary for agro-pastoralism, interspersed by woody vegetation. Recent assessments indicate that vegetation degradation is occurring, adversely impacting fragile ecosystems and human livelihoods. Using AVHRR and MODIS vegetation products from 1981 to 2012, we observe changes in vegetation patterns and productivity over the last decade across the East African Horn. We observe vegetation browning trends in areas experiencing reduced main-growing season precipitation; these areas are also concurrently experiencing increasing population pressures. We also found that the drying precipitation patterns only partially statistically explain the vegetation browning trends, indicating that other factors such as population pressures and land use changes might be responsible for the observed declining vegetation condition. Furthermore, we show that the general vegetation browning trends persist even during years with normal rainfall conditions such as 2012, pointing to potential long-term degradation of rangelands on which approximately 10 million people depend. These findings may have implications for current and future regional food security monitoring and forecasting as well as for mitigation and adaptation strategies in a region where population is expected to continue increasing against a backdrop of drying climate trends and increased climatic variability.
Publication date: November 2013
Source:Clinical Simulation in Nursing, Volume 9, Issue 11
Author(s): Yeoun Soo Kim-Godwin , Kae Rivers Livsey , Debbie Ezzell , Carol Highsmith , Heidi Winslow , Ashley N. Aikman
Background Peer evaluation is an effective technique for successful simulation in nursing because it enhances active student engagement in the learning process. The purpose of this descriptive study was to examine students' perceptions of learning effectiveness, fidelity, and satisfaction with peer evaluation during a home visit simulation with a standardized patient. Method Study participants included 50 undergraduate nursing students at a Southeastern university who were enrolled in a community health nursing course. After the completion of the home visit simulation and peer evaluation, students were asked to complete an online survey. Results Students reported peer evaluation to be highly effective and satisfactory for their learning needs. On a 5-point Likert-type scale (from 1 = strongly disagree to 5 = strongly agree), students generally perceived that their peer evaluation experience helped them to improve in the areas of (a) assessment (M = 4.52, SD = 0.76), (b) communication (M = 4.46, SD = 0.76), (c) critical thinking (M = 4.53, SD = 0.68), (d) technical skills (M = 4.46, SD = 0.73), and (e) overall performance (M = 4.49, SD = 0.73). Conclusion Students perceived that the home visit simulation provided them with a good learning opportunity, that they learned vicariously by watching peers, and that they used peers' critiques to strengthen their own simulation experience. Findings of the current study also suggest that the use of a standardized patient and integration of the peer evaluation were perceived by students as an innovative and effective teaching method.
The magic number 70 (plus or minus 20): Variables determining performance in the Rodent Odor Span Task
Publication date: August 2013
Source:Learning and Motivation, Volume 44, Issue 3
Author(s): L. Brooke April , Katherine Bruce , Mark Galizio
The olfactory span task (OST) uses an incrementing non-matching to sample procedure such that the number of stimuli to remember increases during the session. The number of consecutive correct responses (span length) and percent correct as a function of the memory load have been viewed as defining rodent working memory capacity limitations in several studies using the OST. However, the procedural parameters of the OST vary across experiments and their effects are not well understood. For example, in several studies, the number of stimuli to remember is confounded with the number of comparison stimuli displayed in the test arena. Experiment 1 addressed whether performance is influenced by the number of comparison choices available on any given trial (2, 5, 10) as well as the number of odor stimuli to remember during a session (12, 24, 36). Performance was most accurate when the number of stimuli to remember was low, as would be expected from a working memory interpretation of OST. However, accuracy was also affected by the number of comparison stimulus choices. High levels of accuracy were seen even with 36 odors, suggesting that the capacity for odor memory in rats was greater than suggested by previous research. Experiment 2 attempted to define this capacity by programming sessions with 36, 48 or 72 stimuli to remember in a group of rats that had previously received extensive OST training. Highly accurate performance (80% correct or better) was sustained throughout the session at even the greatest memory loads, arguing strongly against the notion that the OST models the limited capacity of human working memory. Experiment 3 explored the possibility that stimulus control in the OST is based on relative stimulus familiarity, rather than recognition of stimuli not yet presented during the current session. Number of odor cups visited increased with the number of comparisons in the arena, but rats rarely sampled all of the comparison odors before responding. However, on probe trials which included only stimuli that had been presented during the session, latency to respond and number of comparisons sampled was sharply increased. These data suggest that responding in the OST is determined not just by relative familiarity, but rather by a more specific “what-when” or perhaps “how long ago” form of stimulus control.
Perceptions of accountability in family business: Using accountability theory to understand differences between family and nonfamily executives
Publication date: December 2013
Source:Journal of Family Business Strategy, Volume 4, Issue 4
Author(s): Rebecca M. Guidice , Neal P. Mero , Juanne V. Greene
Family business success rests on implementing a governance system that recognizes a complex nexus of social relationships. While scholars have used existing frameworks such as agency theory to explore the effect of financial incentives on agent behavior and performance, they have not integrated perspectives from psychology and sociology in a way that fully addresses the challenges of effective family business governance. Our research advances current knowledge of governance in family business by examining the implications of accountability theory to explore differences in the perceptions of accountability between family and nonfamily executives as a result of family firm monitoring. We examine the elements and linkages that form the basis of accountability in the context of firm characteristics uniquely common to family business and that are influential in the development of perceptions between executives of contrasting family status. Potential contingencies to the family status–accountability relationship is also considered, as are the implications of effective monitoring for family firm performance.
Publication date: Available online 23 September 2013
Source:Research in International Business and Finance
Author(s): Clara Maria Verduch Arosa , Nivine Richie , Peter W. Schuhmann
This study uses Hofstede's (2001) cultural dimensions to investigate the impact of market reception on capital structure. We examine the interaction of these dimensions with stock returns, our proxy for market timing. Based on our market leverage results, we find evidence that firms do engage in market timing by reducing their leverage ratios when their share prices increase. Furthermore, we find that firms in countries with high uncertainty avoidance and high power distance have lower market leverage ratios and that these cultural dimensions serve to reduce the impact of market timing. These results are consistent for developed markets but mixed for emerging markets. On a book leverage basis, the results are generally consistent but less conclusive. To the extent that culture impacts manager perception of risk and investor reception of newly issued shares, we conclude that cultural dimensions impact the degree to which a firm can modify its capital structure to take advantage of perceived market mispricings.
Publication date: November–December 2013
Source:Journal of Criminal Justice, Volume 41, Issue 6
Author(s): Anne-Marie R. Iselin , Marcello Gallucci , Jamie DeCoster
Purpose Despite accumulating evidence against the practice of artificial dichotomization, its continued use among criminal justice researchers indicates that there are still unresolved questions about its appropriateness. Farrington and Loeber (2000) provided a discussion of how these issues impact research on delinquency, and many researchers have cited their article as a justification for dichotomization within the field of criminal justice. In the current study, we examine the reasons why researchers have cited Farrington and Loeber as a mechanism for answering some unresolved questions about whether and when dichotomization may be justified. Methods We used a forward citation search in PsycInfo to locate all articles citing Farrington and Loeber (2000) in support of dichotomization. Results This search identified 126 articles which provided a total of 191 reasons supporting dichotomization. We explore these reasons, discussing whether they are consistent with evidence from simulation-based analyses and whether they are supported by existing statistical and methodological theory. Conclusions Despite the large number of reasons for dichotomization provided by authors, we found very few that had empirical or theoretical support.
Trophic calculations reveal the mechanism of population-level variation in mercury concentrations between marine ecosystems: Case studies of two polar seabirds
Publication date: 15 October 2013
Source:Marine Pollution Bulletin, Volume 75, Issues 1–2
Author(s): Rebecka L. Brasso , Michael J. Polito
The incorporation of quantitative trophic level analysis in ecotoxicological studies provides explanatory power to identify the factors, trophic or environmental, driving population-level variation in mercury exposure at large geographic scales. In the Antarctic marine ecosystem, mercury concentrations and stable isotope values in Adélie penguins (Pygoscelis adeliae) were compared between the Antarctic Peninsula and the Ross Sea. Correcting tissue δ15N values for baseline δ15N values revealed population-level differences in trophic position which contributes to differences in mercury. Data from Thick-billed murres (Uria lomvia) were synthesized from published values from Baffin Bay and Svalbard to demonstrate the utility of baseline δ15N values in identifying differences in environmental mercury exposure independent of diet. Here, we demonstrate the importance of calculating population-specific trophic level data to uncover the source of variation in mercury concentrations between geographically distinct populations of marine predators.
Improving macroscopic maturity determination in a pre-spawning flatfish through predictive modeling and whole mount methods
Publication date: October 2013
Source:Fisheries Research, Volume 147
Author(s): Stephen R. Midway , J. Wilson White , William Roumillat , Christopher Batsavage , Frederick S. Scharf
Accurate maturity schedules are essential for informed management of many fishery resources. Although histological methods are generally acknowledged as the best approach to correctly assign maturity status of individual fish, the methods can be expensive and time consuming. We developed and tested a set of multivariable models to predict maturity of southern flounder, a valuable flatfish occupying estuarine and coastal systems in the southeastern US. We also evaluated the potential for whole mount methods to validate maturity assignments and help discriminate transitional oocyte stages. Lastly, we used one of the better performing models to conduct retrospective analysis of variability in southern flounder maturity schedules. Several models performed well in predicting southern flounder maturity; nearly half of the models we tested achieved ≥85% prediction success. We noted that the gonadosomatic index (GSI) was included in most of the higher performing models and, by itself, was a strong predictor of maturity for southern flounder. The addition of novel quantitative predictors, such as gonad color and dimensions, pushed model success above 90% in many cases. Whole mount methods showed a high level of agreement with histological methods, and should be investigated as an inexpensive alternative for validating maturity assignments. Retrospective analysis revealed the potential for interannual fluctuations in L 50 of 2–5cm for southern flounder, which can impact yearly estimates of SSB and target harvest rates. Multivariable predictive models using routinely collected fishery biological data can provide reliable estimates of fish maturity and, when coupled with whole mount methods, should represent an improvement of traditional macroscopic maturity assignment.
Vertebrate records in polar sediments: Biological responses to past climate change and human activities
Publication date: November 2013
Source:Earth-Science Reviews, Volume 126
Author(s): L.G. Sun , S.D. Emslie , T. Huang , J.M. Blais , Z.Q. Xie , X.D. Liu , X.B. Yin , Y.H. Wang , W. Huang , D.A. Hodgson , J.P. Smol
Biological responses to climate and environmental changes in remote polar regions are of increasing interest in global change research. Terrestrial and marine polar ecosystems have suffered from impacts of both rapid climate change and intense human activities, and large fluctuations in the population sizes of seabirds, seals, and Antarctic krill have been observed in the past decades. To understand the mechanisms driving these regime shifts in polar ecosystems, it is important to first distinguish the influences of natural forcing from anthropogenic activities. Therefore, investigations of past changes of polar ecosystems prior to human contact are relevant for placing recent human-induced changes within a long-term historical context. Here we focus our review on the fossil, sub-fossil, archaeological, and biogeochemical remains of marine vertebrates in polar sediments. These remains include well-preserved tissues such as bones, hairs and feathers, and biogeochemical markers and other proxy indicators, including deposits of guano and excrement, which can accumulate in lake and terrestrial sediments over thousands of years. Analyses of these remains have provided insight into both natural and anthropogenic impacts on marine vertebrates over millennia and have helped identify the causal agents for these impacts. Furthermore, land-based seabirds and marine mammals have been shown to play an important role as bio-vectors in polar environments as they transport significant amounts of nutrients and anthropogenic contaminants between ocean and terrestrial ecosystems.
Signal enhancement in solution-cathode glow discharge — optical emission spectrometry via low molecular weight organic compounds
Publication date: 1 October 2013
Source:Spectrochimica Acta Part B: Atomic Spectroscopy, Volume 88
Author(s): Todd A. Doroski , Michael R. Webb
HCOOH, CH3COOH, and CH3CH2OH were used as chemical modifiers in a solution-cathode glow discharge. Emission was measured directly from the discharge, without a gas–liquid separator or a secondary excitation source. Emission from Ag, Se, Pb, and Hg was strongly enhanced, and the detection limits (DL) for these elements were improved by up to an order of magnitude using a combination of HCOOH and HNO3 compared to using HNO3 alone. The DL was measured for Mg (1μg/L), Fe (10μg/L), Ni (6μg/L), Cu (6μg/L), Pb (1μg/L), Ag (0.1μg/L), Se (300μg/L), and Hg (2μg/L). Coefficients of determination (R2) were between 0.9986 and 0.9999. A voltage of 1kV was used, which produced a current of approximately 70mA.
Publication date: 1 October 2013
Source:Applied Mathematics and Computation, Volume 222
Author(s): Wankou Yang , Zhenyu Wang , Jun Yin , Changyin Sun , Karl Ricanek
Sparse representation based classification (SRC) has received much attention in computer vision and pattern recognition. SRC codes a testing sample by sparse linear combination of all the training samples and classifies the testing sample into the class with the minimum representation error. Recently, Zhang analyzes the working mechanism of SRC and points out that it is the collaborative representation but not the L1-norm sparsity that makes SRC powerful. Based on the analysis, they propose a very simple and much more efficient classification scheme, called collaborative representation based classification with regularized least square (CRC_RLS). CRC_RLS is a linear method in nature. Here we propose a kernel collaborative representation based classification with regularized least square (Kernel CRC_RLS, KCRC_RLS) by implicitly mapping the sample into high-dimensional space via kernel tricks. Our approach is highly motivated by the kernel methods which can capture the nonlinear similarity among samples and have been successfully applied in pattern recognition and machine learning. The experimental results on the CENPAMI handwritten digital database, ETH80 database, FERET face database, ORL database, AR face database, demonstrate that Kernel CRC_RLS is effective in classification, leading to promising performance.
Changes in fossil assemblage in sediment cores from Mingulay Reef Complex (NE Atlantic): Implications for coral reef build-up
Publication date: Available online 3 August 2013
Source:Deep Sea Research Part II: Topical Studies in Oceanography
Author(s): Mélanie Douarin , Daniel J. Sinclair , Mary Elliot , Lea-Anne Henry , David Long , Freya Mitchison , J. Murray Roberts
CT scanning and descriptions of sedimentary sequences have been conducted to describe the internal structure and define the evolutionary sequence of events leading to the build-up of cold-water coral reef constructed by the azooxanthellate scleractinian Lophelia pertusa. Two vibrocores containing coral clasts and associated fauna embedded in a matrix of marine sediment were taken at the Mingulay Reef Complex, an inshore (~120–190m water depth) L. pertusa reef off western Scotland. The cores were scanned using computed x-ray tomography (CT scan) with the aim of (1) reconstructing and quantifying the relative abundance and preservation of coral fragments in the cores, (2) identifying distinct reef facies, and hence (3) providing data that could lead to a conceptual model of reef growth. U-series dates were obtained on L. pertusa clasts from the two sediment cores to provide a temporal framework of the reef build-up. After exploring a range of methods for processing CT scans, three simple parameters were used to classify different strata within the cores: the overall density of the cores, the number of fossil clasts, and the sum of the area of clasts detected by the CT scan. These parameters were validated by comparing with density measurements from a multi-sensor core logger (MSCL) and physical dissection and analysis of fossils in the cores. From the CT scan analyses, three distinct reef facies were evident: Coral-Rich, Sediment-Rich and Shelly-Coral Hash Layers. The succession and rapid cycle of reef framework-forming L. pertusa development, disturbance and recovery allow us to provide a model of cold-water coral reef build-up including shifts in biodiversity, physical/chemical/biological processes and the sedimentary regime.