bluuebunny/crossref_metadata_2025_split huggingface dataset:
Does river regulation increase the dominance of invasive woody species in riparian landscapes?
Authors: Mortenson Susan G. , Weisberg Peter J. 
Published: April 2010

ABSTRACTAim  A regional analysis was used to explore the influence of river regulation on the dominance of non‐native, invasive shrubs and trees. We addressed the following questions: (1) How do large dams affect hydrological parameters that influence riparian vegetation? (2) How do flow regimes affect the dominance of non‐native woody species? (3) How do changes in flow regimes affect the dominance of non‐native woody species?Location  South‐western USA.Methods  We sampled the canopy cover of woody species on 179 point bars along seven non‐dammed and thirteen dammed river segments. Wilcoxon rank sum tests were used to determine differences between flow parameters in dammed and non‐dammed rivers. We used correlation analyses and generalized linear model comparisons to examine associations of flow parameters and canopy cover of native (Populus and Salix) and non‐native (Tamarix and Elaeagnus) taxa. An index of flow alteration that was created using principal components analysis was regressed with vegetation cover.Results  Tamarix cover was positively related to drainage area, flow constancy, August and May median flow and flow recession rate, but Elaeagnus cover was unrelated to flow variables. River segments with peak flows in late summer or high constancy had the highest Tamarix cover. Populus cover was positively influenced by low maximum temperatures and frequent high pulses. Flow alteration was negatively related to Populus cover and positively related to Tamarix cover. Total non‐native, Elaeagnus and Salix covers were not correlated with flow alteration.Main conclusions  Rivers with a large drainage area and low flow variability are inherently more vulnerable to invasions. River regulation does not necessarily increase the cover of non‐native, invasive species. Instead, changes in flow allow proliferation of species that have life‐history traits suited to modified flow regimes. River restoration projects that aim to reinstate natural flow regimes should be designed with knowledge of native and non‐native species' life history strategies.
Ecogeographical variation of body size in the newt Triturus carnifex: comparing the hypotheses using an information‐theoretic approach
Authors: Ficetola Gentile Francesco , Scali Stefano , Denoël Mathieu , Montinaro Gianpaolo , Vukov Tanja D. , Zuffi Marco A. L. , Padoa‐Schioppa Emilio 
Published: April 2010

ABSTRACTAim  Ecogeographical variation of body size in vertebrates (e.g. Bergmann's rule) has long been recognized. However, the patterns and causes of intra‐specific ecogeographical variation of body size in ectotherms, and in amphibians in particular, are strongly debated. We identified the relationship between bioclimatic variables and body size predicted a priori by alternative hypotheses (heat balance, endurance, seasonality, starvation resistance, water availability, primary productivity, parental investment) proposed to explain ecogeographical patterns of body size in ectotherms, and we evaluated the relative support of these hypotheses in explaining variation in body size of the Italian crested newt, Triturus carnifex.Location  Twenty‐three populations covering the whole range of T. carnifex (Austria, Croatia, Italy and Slovenia).Methods  We obtained data on body size (snout–vent length, SVL) of 2639 adult newts from direct measurements and the literature; we obtained high‐resolution environmental data for the sampled localities. We used an information‐theoretic approach to evaluate the support of the data for the different hypotheses. We also integrated information on population genetics in our models.Results  We observed strong geographical variation of body size. The best Akaike information criterion (AIC) models showed that populations with larger body size are associated with cold climates and secondarily with high primary productivity. Furthermore, sexual dimorphism increases in cold climates, as the increase in body size was stronger for females. When taking into account population genetics, we did not find support for relationships with the other variables.Main conclusion  Our results are consistent with three hypotheses proposed to explain ecogeographical variation in amphibians: heat balance, increased parental investment of females and productivity. Information theory provides the framework for comparing hypotheses rather than looking for patterns. We suggest that evaluating the support for mechanisms can provide better insights than simply assessing whether ecogeographical variation is in agreement with some ‘rule’.
Phylogeny and co‐occurrence of mammal species on Southeast Asian islands
Authors: Cardillo Marcel , Meijaard Erik 
Published: April 2010

ABSTRACTAim  Islands have often been used as model systems in community ecology. The incorporation of information on phylogenetic relatedness of species in studies of island assemblage structure is still uncommon, but could provide valuable insights into the processes of island community assembly. We propose six models of island community assembly that make different predictions about the associations between co‐occurrences of species pairs on islands, phylogenetic relatedness and ecological similarity. We then test these models using data on mammals of Southeast Asian islands.Location  Two hundred and forty islands of the Sundaland region of Southeast Asia.Methods  We quantified the co‐occurrence of species pairs on islands, and identified pairs that co‐occur more frequently (positive co‐occurrence) or less frequently (negative co‐occurrence) than expected under null models. We then examined the distributions of these significantly deviating pairs with respect to phylogenetic relatedness and ecological differentiation, and compared these patterns with those predicted by the six community assembly models. We used permutation regression to test whether co‐occurrence patterns are predicted by relatedness, body size difference or difference in diet quality. Separate co‐occurrence matrices were analysed in this way for seven mammal families and four smaller subsets of the islands of Sundaland.Results  In many matrices, average numbers of negative co‐occurrences were higher than expected under null models. This is consistent with assemblage structuring by competition, but may also result from low geographic overlap of species pairs, which contributes to negative co‐occurrences at the archipelago‐wide level. Distributions of species pairs within plots of phylogenetic distance × ecological differentiation were consistent with competition, habitat filtering or within‐island speciation models, depending on the taxon. Regressions indicated that co‐occurrence was more likely among closely related species pairs within the Viverridae and Sciuridae, but in most matrices phylogenetic distance was unrelated to co‐occurrence.Main conclusions  Simple deterministic models linking co‐occurrence with phylogeny and ecology are a useful framework for interpreting distributions and assemblage structure of island species. However, island assemblages in Sundaland have probably been shaped by a complex idiosyncratic set of interacting ecological and evolutionary processes, limiting the predictive power of such models.
Assessing the impacts of fragmentation on plant communities in New Zealand: scaling from survey plots to landscapes
Authors: Lafortezza Raffaele , Coomes David A. , Kapos Valerie , Ewers Robert M. 
Published: April 2010

ABSTRACTAim  Few studies have attempted to assess the overall impact of fragmentation at the landscape scale. We quantify the impacts of fragmentation on plant diversity by assessing patterns of community composition in relation to a range of fragmentation measures.Location  The investigation was undertaken in two regions of New Zealand – a relatively unfragmented area of lowland rain forest in south Westland and a highly fragmented montane forest on the eastern slopes of the Southern Alps.Methods  We calculated an index of community similarity (Bray–Curtis) between forest plots we regarded as potentially affected by fragmentation and control forest plots located deep inside continuous forest areas. Using a multiple nonlinear regression technique that incorporates spatial autocorrelation effects, we analysed plant community composition in relation to measures of fragmentation at the patch and landscape levels. From the resulting regression equation, we predicted community composition for every forest pixel on land‐cover maps of the study areas and used these maps to calculate a landscape‐level estimate of compositional change, which we term ‘BioFrag’. BioFrag has a value of one if fragmentation has no detectable effect on communities within a landscape, and tends towards zero if fragmentation has a strong effect.Results  We detected a weak, but significant, impact of fragmentation metrics operating at both the patch and landscape levels. Observed values of BioFrag ranged from 0.68 to 0.90, suggesting that patterns of fragmentation have medium to weak impacts on forest plant communities in New Zealand. BioFrag values varied in meaningful ways among landscapes and between the ground‐cover and tree and shrub communities.Main conclusions  BioFrag advances methods that describe spatial patterns of forest cover by incorporating the exact spatial patterns of observed species responses to fragmentation operating at multiple spatial scales. BioFrag can be applied to any landscape and ecological community across the globe and represents a significant step towards developing a biologically relevant, landscape‐scale index of habitat fragmentation.
Inferring Haplotype/Disease Association by Joint Use of Case‐Parents Trios and Case‐Parent Pairs
Authors: Hu Yue‐Qing , Zhou Ji‐Yuan 
Published: April 2010

SummaryRecently interest has been increasing in genetic association studies using several closely linked loci. The HAP‐TDT method, which uses case‐parents trios is powerful for such a task. However, it is not uncommon in practice that one parent is missing for some reason, such as late onset. The case‐parents trios are thus reduced to case‐parent pairs. Discarding such data could lead to a severe loss of power. In this paper, we propose the HAP‐1‐TDT method based on case‐parent pairs to detect haplotype/disease association. A permutation‐based randomisation technique is devised to assess the significance of the test statistic. Furthermore, the combined statistic HAP‐C‐TDT is developed to use jointly case‐parents trios and case‐parent pairs. These test statistics can be applied to either phase‐known or phase‐unknown data. A number of simulation studies are conducted to investigate the validity of the proposed tests; these studies show that the statistics are robust to population structure. Using several disease genes from the literature, we illustrate that incorporating case‐parent pairs into an association study leads to noticeable power gain. Moreover, our simulation results suggest that our method has better size and power than UNPHASED. Finally, in simulated scenarios where there are only a few SNPs and risk is determined by two haplotypes that are complementary or near‐complementary, our method has better power than TRIMM.
Consumer attitudes and loyalty towards private brands
Authors: Goldsmith Ronald E. , Flynn Leisa R. , Goldsmith Elizabeth , Stacey E. Craig 
Published: April 2010

AbstractPrivate or store brands improve the efficiency of consumer decision making by offering equivalent quality products at lower prices. The present study evaluated consumer attitudes towards private brands with the goal of understanding their appeal in order to enhance efforts to convince more consumers to buy them. We used three samples (ns = 279, 245 and 305) of US consumers to compare attitudes of buyers of private and national brands in three product categories: orange juice, cereal and bottled water. The results show that private label buyers (23% of orange juice, 6.5% of cereal and 14% of bottled water buyers) consider brands themselves to be less important and private brands to offer better performance than do national brand buyers. When asked about specific brands, national brand buyers tended to be price insensitive towards national brands, and private label buyers price insensitive towards store brands. In addition, the national brand buyers saw some of the national brands to be more relevant to their lifestyles and needs, but the private label buyers saw the private labels the same way. Being relevant to consumers' lives appears to influence brand selection. Besides touting lower prices, private brand promotions might stress the equivalent performance of private labels and create promotions showing how these brands can be relevant to consumers' lifestyles and needs.
Mitochondrial protection after traumatic brain injury by scavenging lipid peroxyl radicals
Authors: Mustafa Ayman G. , Singh Indrapal N. , Wang Juan , Carrico Kimberly M. , Hall Edward D. 
Published: April 2010

J. Neurochem.(2010)114, 271–280.AbstractMitochondrial dysfunction after traumatic brain injury (TBI) is manifested by increased levels of oxidative damage, loss of respiratory functions and diminished ability to buffer cytosolic calcium. This study investigated the detrimental effects of lipid peroxyl radicals (LOO•) and lipid peroxidation (LP) in brain mitochondria after TBI by examining the protective effects of U‐83836E, a potent and selective scavenger of LOO•radicals. Male CF1 mice were subjected to severe controlled cortical impact TBI (CCI‐TBI) and treated with either vehicle or U‐83836E initiated i.v. at 15 min post‐injury. Calcium (Ca++) buffering capacity and respiratory function were measured in isolated cortical mitochondrial samples taken from the ipsilateral hemisphere at 3 and 12 h post‐TBI, respectively. In vehicle‐treated injured mice, the cortical mitochondrial Ca++buffering capacity was reduced by 60% at 3 h post‐injury (p < 0.001) and the respiratory control ratio was decreased by 27% at 12 h post‐TBI, relative to sham, non‐injured mice. U‐83836E treatment significantly (p < 0.05) preserved Ca++buffering capacity and attenuated the reduction in respiratory control ratio values. Consistent with the functional effects of U‐83836E being as a result of an attenuation of mitochondrial oxidative damage, the compound significantly (p < 0.001) reduced LP‐generated 4‐hydroxynonenal levels in both cortical homogenates and mitochondria at both 3 and 12 h post‐TBI. Unexpectedly, U‐83836E also reduced peroxynitrite‐generated 3‐nitrotyrosine in parallel with the reduction in 4‐hydroxynonenal. The results demonstrate that LOO•radicals contribute to secondary brain mitochondrial dysfunction after TBI by propagating LP and protein nitrative damage in cellular and mitochondrial membranes.
Brain Apparent Water Diffusion Coefficient Magnetic Resonance Image During a Prolonged Visual Aura
Authors: Belvís Robert , Ramos Rafael , Villa Carolina , Segura Cristóbal , Pagonabarraga Javier , Ormazabal Inmaculada , Kulisevsky Jaime 
Published: April 2010

(Headache2010;50:1045‐1049)Background.—Reversible changes in brain magnetic resonance imaging (MRI) weighted in diffusion‐weighted images (DWI) and apparent water diffusion coefficient (ADC) maps have been reported in acute stroke, epilepsy, eclampsia, and hypoglycemia, but they are contradictory regarding to migraine aura.Objective.—A 41‐year‐old woman with known basilar migraine for 5 years consulted about a persistent visual aura (visual snow phenomenon) plus bilateral paresthesias in the extremities for 4 days. The headache was treated with success with 10 mg of wafer rizatriptan and 600 mg of ibuprophen.Methods.—The neurologic and ophthalmologic examination were normal. An urgent brain MRI detected no lesions in T1, T2, fluid‐attenuated inversion recovery, and DWI, but an abnormal signal appeared in the left occipital lobe in ADC and (r)ADC maps. The brain MRI angiography, carotid ultrasound study, transesophageal echocardiography, 24‐hour cardiac Holter monitoring, and thrombophilia study were normal.Results.—A new brain MRI 8 days after did not show any previous lesion in the same sequences.Conclusions.—We present a patient with migraine and transitory abnormal signals in the ADC map of an occipital region during persistent visual aura. The clinical‐radiological relationship is congruent. Some similar cases have showed these MRI signals during the aura, suggesting cytotoxic edema, without ischemic lesions in the MRI controls. Theses ADC images probably appear in complex auras.
An Approach to Integrating Environmental Considerations Within Managerial Decision‐Making
Authors: Subramanian Ravi , Talbot Brian , Gupta Sudheer 
Published: April 2010

SummaryRecent environmental trends, including (1) an expansion of existing command and control directives, (2) the introduction of market‐based policy instruments, and (3) the adoption of extended producer responsibility, have created a need for new tools to help managerial decision‐making. To address this need, we develop a nonlinear mathematical programming model from a profit‐maximizing firm's perspective, which can be tailored as a decision‐support tool for firms facing environmental goals and constraints. We typify our approach using the specific context of diesel engine manufacturing and remanufacturing. Our model constructs are based on detailed interviews with top managers from two leading competitors in the medium and heavy‐duty diesel engine industry. The approach allows the incorporation of traditional operations‐planning considerations—in particular, capacity, production, and inventory—together with environmental considerations that range from product design through production to product end of life. A current hurdle to implementing such a model is the availability of input data. We therefore highlight the need not only to involve all departments within businesses but also for industrial ecologists and business managers to work together to implement meaningful decision models that are based on accurate and timely data and can have positive economic and environmental impact.
Practical limitations of convalescent plasma collection: a case scenario in pandemic preparation for influenza A (H1N1) infection
Authors: Wong Hoi K. , Lee Cheuk K. , Hung Ivan F.N. , Leung Jennifer N.S. , Hong Juliana , Yuen Kwok Y. , Lin Che K. 
Published: April 2010

BACKGROUND: To ensure a good preparedness for pandemic influenza A (H1N1), a study was conducted to investigate clinical effectiveness of hyperimmune intravenous globulin (H‐IVIG) prepared from convalescent plasma donated by recovered patients. This article reports on the outcome of the collection phase of the study.STUDY DESIGN AND METHODS: Starting on August 26, 2009, all confirmed patients aged between 18 and 55 years were invited for participation into the study and screen for plasma donation eligibility. Effective September 17, 2009, those who were unwilling to consider screening for plasma were asked to donate whole blood. Plasma collected or separated from whole blood had to demonstrate sufficient neutralization antibodies titers of 40 or more before being channeled for H‐IVIG production.RESULTS: By October 31, 2009, a total of 9101 persons were successfully contacted. A total of 1309 screening and 619 whole blood donation appointments were made. In the former 786 (60.0%) attended screening but only 301 could donate plasma by apheresis because of failure to meet blood donation eligibility criteria, failed laboratory tests, insufficient neutralization antibody titers, and inability to make the apheresis appointment. For those who opted for whole blood donation, 379 (61.2%) had attended and donated. A total of 276 L of convalescent plasma with sufficient neutralization antibodies titers was collected for H‐IVIG production.DISCUSSION: The study highlighted a number of practical limitations in convalescent plasma collection programs and plasmapheresis is always the preferred mode of collection. It provided valuable learning experience for the blood transfusion service in future planning when large‐scale collection is required.
Is Gold a Hedge or a Safe Haven? An Analysis of Stocks, Bonds and Gold
Authors: Baur Dirk G. , Lucey Brian M. 
Published: April 2010

AbstractIs gold a hedge, defined as a security that is uncorrelated with stocks or bonds on average, or is it a safe haven, defined as a security that is uncorrelated with stocks and bonds in a market crash? We study constant and time‐varying relations between U.S., U.K. and German stock and bond returns and gold returns to investigate gold as a hedge and a safe haven. We find that gold is a hedge against stocks on average and a safe haven in extreme stock market conditions. A portfolio analysis further shows that the safe haven property is short‐lived.
Does the Quality of Financial Advice Affect Prices?
Authors: Allen Arthur , Dudney Donna 
Published: April 2010

AbstractUsing a large data sample of 58,562 new municipal issues covering the period from 1984 to 2002, we examine whether the quality of advice provided by a financial advisor affects new issue interest costs. We find that higher‐quality financial advisors are associated with statistically significant decreases in new issue yields. The effect of advisor quality on yields is more pronounced for revenue, negotiated, and opaque bond issues than for general obligation and competitively sold issues. However, issuers of revenue or negotiated bonds are more likely to choose a low‐quality advisor.
Arbitrage and the Evaluation of Linear Factor Models in UK Stock Returns
Authors: Fletcher Jonathan 
Published: April 2010

AbstractI examine the impact of the no arbitrage restriction on the estimation and evaluation of linear factor models in UK stock returns. The no arbitrage restriction reduces volatility and eliminates most of the negative values of the fitted stochastic discount factor models. All of the factor models are rejected and there are significant differences in the pricing performance between models under the no arbitrage restriction. The no arbitrage restriction can have a significant impact on both the parameter estimates and pricing errors for some models.
Short‐Horizon Return Predictability in International Equity Markets
Authors: Shamsuddin Abul , Kim Jae H. 
Published: April 2010

AbstractThis study measures the degree of short‐horizon return predictability of 50 international equity markets and examines how its variation is related to the indicators of equity market development. Two multiple‐horizon variance ratio tests are employed to measure the degree of return predictability. We find evidence that return predictability is negatively correlated with publicly available indicators of equity market development. Our cross‐sectional regression analysis shows that the per capita gross domestic product, market turnover, investor protection, and absence of short‐selling restrictions are correlated with cross‐market variations in return predictability.