bluuebunny/crossref_metadata_2025_split huggingface dataset:
Frequent occurrence of the human‐specific Bacteroides fecal marker at an open coast marine beach: relationship to waves, tides and traditional indicators
Authors: Santoro Alyson E. , Boehm Alexandria B. 
Published: May 2007

SummaryMolecular genetic markers, such as those from fecal Bacteroides microorganisms, can link microbial pollution with its source, and have been used successfully in studies of sheltered aquatic environments. Their applicability to wave‐driven, open coast environments has not been tested. We assessed the contribution of a tidal outlet to surf zone water quality in coastal Orange County, California, USA by measuring three traditional culture‐based fecal indicator bacteria (FIB) as well as the human‐specific Bacteroides molecular marker (HF marker) at four shoreline locations. We found that total and fecal coliform levels were higher during low tides than high tides at two of the four stations, and that this effect was strongest at the mouth of the tidal lagoon and decayed with distance from the outlet. The HF marker was detected in 23% and 47% of samples from the tidal outlet and 26% and 41% of samples from an adjacent recreational beach in 2005 and 2006 respectively. Surprisingly, the station farthest from the tidal outlet had the highest occurrence of the HF marker. We found no relationship between FIB abundance and occurrence of the HF marker for individual samples, but that when the data were considered together by year, higher FIB abundance was correlated with a higher incidence of the HF marker. DNA sequences of the HF marker recovered from this site were > 99% similar to those recovered from other states and countries, suggesting low global diversity of this marker. These data provide strong support for the idea that multiple time points and physical conditions should be considered when assessing coastal water quality.
Interactive effects of solar radiation and dissolved organic matter on bacterial activity and community structure
Authors: Pérez María Teresa , Sommaruga Ruben 
Published: May 2007

SummaryWe studied the interactive effects of dissolved organic matter (DOM) and solar radiation on the activity and community structure of bacteria from an alpine lake. Activity was assessed both at the community level as leucine incorporation rates and at the single‐cell level by microautoradiography. Fluorescent in situ hybridization and signal amplification by catalysed reporter deposition (CARD‐FISH) was used to track changes in the bacterial community composition. Bacteria‐free filtrates of different DOM sources (lake, algae or soil) were incubated either in the dark or exposed to solar radiation. Afterwards, the natural bacterial assemblage was inoculated and the cultures incubated in the dark for 24–48 h. Bacterial activity was enhanced in the first 24 h in the soil and algal DOM amendments kept in the dark. After 48 h, the enhancement effect was greatly reduced. The initial bacterial community was dominated by Betaproteobacteria followed by Actinobacteria. The relative abundance (expressed as a percentage of DAPI‐stained cells) of Betaproteobacteria increased first in dark incubated DOM amendments, but after 48 h no significant differences were detected among treatments. In contrast, the relative abundance of Actinobacteria increased in pre‐irradiated DOM treatments. Although Betaproteobacteria dominated at the end of the experiment, the relative abundance of their R‐BT subgroup differed among treatments. Changes in bacterial community activity were significantly correlated with those of the relative abundance and activity of Betaproteobacteria, whereas the contribution of Actinobacteria to the bulk activity was very modest. Our results indicate a negative effect of DOM photoalteration on the bulk bacterial activity. The magnitude of this effect was time‐dependent and related to rapid changes in the bacterial assemblage composition.
Rosiglitazone RECORD study: glucose control outcomes at 18 months
Authors: Home P. D. , Jones N. P. , Pocock S. J. , Beck‐Nielsen H. , Gomis R. , Hanefeld M. , Komajda M. , Curtis P. ,   for the RECORD Study Group
Published: May 2007

AbstractAims  To compare glucose control over 18 months between rosiglitazone oral combination therapy and combination metformin and sulphonylurea in people with Type 2 diabetes.Methods  RECORD, a multicentre, parallel‐group study of cardiovascular outcomes, enrolled people with an HbA1c of 7.1–9.0% on maximum doses of metformin or sulphonylurea. If on metformin they were randomized to add‐on rosiglitazone or sulphonylurea (open label) and if on sulphonylurea to rosiglitazone or metformin. HbA1c was managed to ≤ 7.0% by dose titration. A prospectively defined analysis of glycaemic control on the first 1122 participants is reported here, with a primary outcome assessed against a non‐inferiority margin for HbA1c of 0.4%.Results  At 18 months, HbA1c reduction on background metformin was similar with rosiglitazone and sulphonylurea [difference 0.07 (95% CI −0.09, 0.23)%], as was the change when rosiglitazone or metformin was added to sulphonylurea [0.06 (−0.09, 0.20)%]. At 6 months, the effect on HbA1c was greater with add‐on sulphonylurea, but was similar whether sulphonylurea was added to rosiglitazone or metformin. Differences in fasting plasma glucose were not statistically significant at 18 months [rosiglitazone vs. sulphonylurea −0.36 (−0.74, 0.02) mmol/l, rosiglitazone vs. metformin −0.34 (−0.73, 0.05) mmol/l]. Increased homeostasis model assessment insulin sensitivity and reduced C‐reactive protein were greater with rosiglitazone than metformin or sulphonylurea (all P ≤ 0.001). Body weight was significantly increased with rosiglitazone compared with sulphonylurea [difference 1.2 (0.4, 2.0) kg, P = 0.003] and metformin [difference 4.3 (3.6, 5.1) kg, P < 0.001].Conclusions  In people with diabetes, rosiglitazone in combination with metformin or sulphonylurea was demonstrated to be non‐inferior to the standard combination of metformin + sulphonylurea in lowering HbA1c over 18 months, and produces greater improvements in C‐reactive protein and basal insulin sensitivity but is also associated with greater weight gain.
Building the Future of Learning
Authors: WATSON LES 
Published: May 2007

Could it be that in our excitement about e‐learning we forgot about buildings? With the advent of the personal computer and ubiquitous networks were we enticed into thinking that they would suffice and learning would follow removing the need for places and communities for learners? We now seem to have woken up, however, as there is an enormous resurgence of interest in new building in Universities, Schools and Colleges — a real opportunity to ‘build’ our learning futures. But if the interest is just in building then it's an opportunity lost. However, if it is about transformation, place and community we could create the connected learning society, both physically and virtually, that we aspire to.New 21st century buildings and refurbished spaces should reflect our educational approaches and philosophies and, even more importantly, they should not disable tomorrow's possibilities. The buildings that we build today can prevent us from doing what tomorrow might become the dominant ways of working and learning. Our buildings should combine educational ideas, with imaginative technology and architecture to create the learning futures we wish to see.The Saltire Centre at Glasgow Caledonian University, which opened in January 2006, started from the premise of a building that is flexible and does not disable the future. The building, through its variety of spaces, embraces learner differences and supports a concept of learning as a social process putting human social interaction and conversation at its heart. This article uses the Saltire Centre as a case study to illustrate how some current key ideas in educational thinking can influence the learning facilities that we provide.
Water vapour permeability of skin care products in relation to molecular and environmental influences
Authors: STRÜBMANN A. , WEIßEN H.‐J. , WIRTZ A. 
Published: May 2007

SynopsisAn in vitro method for characterization of water retention behaviour of emollients was developed. The human skin is imitated with the aid of a polytetrafluoro ethylene membrane and the degree of water vapour evaporation after impregnation with different emollients is determined. Results obtained from different studies under changing conditions indicate that this is a precise and efficient method which is easy to perform with very simple equipment. It allows the generation of data for the characterization of emollients as an aid for skin care product formulation. Additionally, basic studies on emollient water retention due to exogenous influences are possible.RésuméUne méthode in vitro pour caractéroen l'aptitude a'la rétention d'eau d'un émolliant a été mise au point. La peau humaine est simulée avec l'aide d'une membrane en polytetrafluoro éthylène (PTFE), et l'evaporation de la voyeur d'eau après impregnation avec divers émolliants est mesurée. Après différentes études dans diverses conditions expérimentales, les résultats obtenus montrent qu'une méthode précise et efficaee a été développée, facile à methe en ocuore avec un équipement simple. Elle permet d'obtenin les donnécs caractéristiques d'émolliants, facilitant le formulation de produits de soin pour la peau. Des études supplémentaires concernant l'évolution de la capacitéà la rétention d'eau d'un émolliant en fonction de facteurs exterieurs sont envisageables.
Effects of resistance training on metabolic fitness in children and adolescents: a systematic review
Authors: Benson A. C. , Torode M. E. , Fiatarone Singh M. A. 
Published: May 2007

SummaryThe majority of resistance training (RT) research with children to date has focused on pre‐adolescents and the safety and efficacy of this type of training rather than the potential metabolic health benefits. Our objectives, using computerized databases, were (i) to systematically review studies utilizing RT interventions with children and adolescents <18 years; (ii) to investigate the metabolic health outcomes (adiposity, lipids, insulin, glucose) associated with RT; (iii) to provide recommendations for future investigations. A total of 12 studies met the review criteria. There is only a small amount of evidence that children and adolescents may derive metabolic health‐related adaptations from supervised RT. However, methodological limitations within the body of this literature make it difficult to determine the optimal RT prescription for metabolic fitness in children and adolescents, and the extent and duration of such benefits. More robustly designed single modality randomized controlled trials utilizing standardized reporting and precise outcome assessments are required to determine the extent of health outcomes attributable solely to RT and to enable the development of evidence‐based obesity prevention and treatment strategies in this cohort.
e‐Learning: The student experience
Authors: Gilbert Jennifer , Morton Susan , Rowley Jennifer 
Published: May 2007

AbstractThe paper draws on in‐depth qualitative. comments from student evaluation of an e‐learning module on an MSc in Information Technologies and Management, to develop a picture of their perspective on the experience. Questionnaires that yielded some basic quantitative data and a rich seam of qualitative data were administered. General questions on satisfaction and dissatisfaction identified the criteria that student used in evaluation, while specific questions of aspects of the module generated some insights into the student learning process. The criteria used by students when expressing satisfaction are: synergy between theory and practice; specific subject themes; discussion forums and other student interaction; and, other learning support. The themes that are associated with dissatisfaction include: robustness and usability of platform; access to resources (such as articles and books); currency of study materials; and, student work scheduling. Aspects of the student learning experience that should inform the development of e‐learning include: each student engages differently; printing means that students use the integrated learning environment as a menu; discussion threads and interaction are appreciated, but students are unsure in making contributions; and, expectations about the tutor's role in e‐learning are unformed.
External Shocks, Bank Lending Spreads, and Output Fluctuations*
Authors: Agénor Pierre‐Richard , Aizenman Joshua , Hoffmaister Alexander W. 
Published: May 2007

AbstractThis paper studies the effects of external shocks on bank lending spreads and output fluctuations in Argentina during the early 1990s. The first part presents the analytical framework. The second presents a VAR model that relates bank lending spreads, the cyclical component of output, the real lending rate, and the external interest rate spread. Impulse response functions show that a positive shock in external spreads leads to higher domestic spreads and lower output. Historical decompositions show that shocks to external spreads in the immediate aftermath of the Mexican peso crisis had a sizable effect on movements in output and domestic spreads.
A Model of Endogenous Nontradability and its Implications for the Current Account*
Authors: Bergin Paul , Glick Reuven 
Published: May 2007

AbstractThis paper studies how nontraded goods limit the ability of a country to finance current account deficits. It uses an intertemporal model of the current account for a small open economy where goods are endogenously nontraded due to explicit trade costs. The economy has an endowment of two goods with differing trade costs, either of which can be traded or nontraded in equilibrium. The model implies that current account deficits impose a cost, in the form of raising the effective interest rate in the country. The findings differ from some recent studies: first, in that the interest rate rises even for countries with modest current account deficits; secondly, the interest rate cost eventually reaches an upper bound as current account deficits grow, and progressively more nontraded goods become traded to service the debt. Panel regression analysis of interest rate and current account data is consistent with our conclusions.
Sustaining Collusion under Economic Integration*
Authors: Colombo Luca , Labrecciosa Paola 
Published: May 2007

AbstractIn this paper, we aim at investigating from a game‐theory perspective whether trade liberalization can promote a collusive two‐way trade. We show that, under Cournot competition, economic integration is anti‐competitive if collusive trade is a possible outcome of the repeated game; under price competition, the likelihood of collusive trade is a necessary but not sufficient condition for trade liberalization to be pro‐competitive. Furthermore, we show that economic integration may increase the scope for collusion irrespective of the firms’ strategic variable.
On Functionally Distributed Quotas
Authors: Gilbert John 
Published: May 2007

AbstractWe consider “functionally distributed” quotas, where trade is restricted to a function of another economic activity, paying special attention to the ratio constraint and its relation to “proportionally distributed” quotas. We propose a simple principle defining the optimal policy under a functionally defined restriction, extend the analysis of ratio import/production constraints to general equilibrium, introduce export constraints, and constraints defined in proportion to factor use. We develop the general‐equilibrium geometry of functional trade constraints and the concomitant optimal policies, deriving a “quota locus” that depicts the consumption possibilities under various regimes.
International R&D Spillovers: Trade, FDI, and Information Technology as Spillover Channels*
Authors: Zhu Lei , Jeon Bang Nam 
Published: May 2007

AbstractWith the rapid pace of economic integration, the productivity of a country depends not only on domestic R&D, but also on foreign R&D through technology diffusion across countries. The advancement of information technology (IT) has made the international transmission of knowledge faster and more efficient, providing an important channel for international R&D spillovers. This paper investigates three channels of international R&D spillovers: trade, FDI, and information technology. Applying panel cointegration and dynamic OLS analysis to the data for 21 OECD countries plus Israel during the period from 1981 to 1998, we find that bilateral trade remains an important conduit for international R&D spillovers. Although bilateral FDI is found to be positively related to international R&D spillovers, their impact on productivity growth is relatively small. We also find that the development of information technology has played a more important role in international R&D spillovers and productivity growth in recent years.
Mixture Cure Survival Models With Dependent Censoring
Authors: Li Yi , Tiwari Ram C. , Guha Subharup 
Published: May 2007

SummaryThe paper is motivated by cure detection among the prostate cancer patients in the National Institutes of Health surveillance epidemiology and end results programme, wherein the main end point (e.g. deaths from prostate cancer) and the censoring causes (e.g. deaths from heart diseases) may be dependent. Although many researchers have studied the mixture survival model to analyse survival data with non-negligible cure fractions, none has studied the mixture cure model in the presence of dependent censoring. To account for such dependence, we propose a more general cure model that allows for dependent censoring. We derive the cure models from the perspective of competing risks and model the dependence between the censoring time and the survival time by using a class of Archimedean copula models. Within this framework, we consider the parameter estimation, the cure detection and the two-sample comparison of latency distributions in the presence of dependent censoring when a proportion of patients is deemed cured. Large sample results by using martingale theory are obtained. We examine the finite sample performance of the proposed methods via simulation and apply them to analyse the surveillance epidemiology and end results prostate cancer data.
Analysis of Failure Time Data Under Competing Censoring Mechanisms
Authors: Rotnitzky Andrea , Farall Andres , Bergesio Andrea , Scharfstein Daniel 
Published: May 2007

SummaryWe derive estimators of the survival curve of a failure time in the presence of competing right censoring mechanisms. Our approach allows for the possibility that some or all of the competing censoring mechanisms are associated with the end point, even after adjustment for recorded prognostic factors. It also allows the degree of residual association to be possibly different for distinct censoring processes. Our methods generalize from one to several competing censoring mechanisms the methods of Scharfstein and Robins.
Bootstrapping Clustered Data
Authors: Field C. A. , Welsh A. H. 
Published: May 2007

SummaryVarious bootstraps have been proposed for bootstrapping clustered data from one-way arrays. The simulation results in the literature suggest that some of these methods work quite well in practice; the theoretical results are limited and more mixed in their conclusions. For example, McCullagh reached negative conclusions about the use of non-parametric bootstraps for one-way arrays. The purpose of this paper is to extend our understanding of the issues by discussing the effect of different ways of modelling clustered data, the criteria for successful bootstraps used in the literature and extending the theory from functions of the sample mean to include functions of the between and within sums of squares and non-parametric bootstraps to include model-based bootstraps. We determine that the consistency of variance estimates for a bootstrap method depends on the choice of model with the residual bootstrap giving consistency under the transformation model whereas the cluster bootstrap gives consistent estimates under both the transformation and the random-effect model. In addition we note that the criteria based on the distribution of the bootstrap observations are not really useful in assessing consistency.
Inference of Trends in Time Series
Authors: Wu Wei Biao , Zhao Zhibiao 
Published: May 2007

SummaryWe consider statistical inference of trends in mean non-stationary models. A test statistic is proposed for the existence of structural breaks in trends. On the basis of a strong invariance principle of stationary processes, we construct simultaneous confidence bands with asymptotically correct nominal coverage probabilities. The results are applied to global warming temperature data and Nile river flow data. Our confidence band of the trend of the global warming temperature series supports the claim that the trend is increasing over the last 150 years.
Orthogonal Locally Ancillary Estimating Functions for Matched Pair Studies and Errors in Covariates
Authors: Wang Molin , Hanfelt John J. 
Published: May 2007

SummaryWe propose an estimating function method for two related applications, matched pair studies and studies with errors in covariates under a functional model, where a mismeasured unknown scalar covariate is treated as a fixed nuisance parameter. Our method addresses the severe inferential problem that is posed by an abundance of nuisance parameters in these two applications. We propose orthogonal locally ancillary estimating functions for these two applications that depend on merely the mean model and partial modelling of the variances of the observations (and observed mismeasured covariate, if applicable), and we achieve first-order bias correction of inferences under a ‘small dispersion and large sample size’ asymptotic. Simulation results confirm that the estimator proposed is largely improved over that using a regular profile estimating function. We apply the approach proposed to a length of hospital stay study with a mismeasured covariate.
Coefficient Sign Prediction Methods for Model Selection
Authors: Nott David J. , Kuk Anthony Y. C. 
Published: May 2007

SummaryWe consider a Bayesian model selection strategy based on predicting the signs of the coefficients in a regression model, i.e. we consider identification of coefficients in a full or encompassing model for which we can confidently predict whether they are positive or negative. This is useful when our main purpose in doing model selection is interpretation, since the sign of a coefficient is often of primary importance for this task. In the case of a linear model with standard non-informative prior, we connect our sign coefficient prediction approach to the classical Zheng–Loh procedure for model selection. One advantage of our approach is that only specification of a prior on the full model is required, unlike standard Bayesian variable selection approaches which require specification of prior distributions on parameters in all submodels, and specification of a prior on the model itself. We consider applying our method with proper hierarchical shrinkage priors, which makes the procedure more useful in ‘large p, small n’ regression problems with more predictors than observations and in problems involving multicollinearity. In these problems we may wish to do prediction by using shrinkage methods in the full model, but interpreting which variables are important is also of interest. We compare selection by using our coefficient sign prediction approach with the recently proposed elastic net procedure of Zou and Hastie and observe that our method shares some of the features of the elastic net such as a group selection property. The method can be extended to more complex model selection problems such as selection on variance components in random-effects models. For selection on variance components where the parameter of interest is non-negative and hence prediction of the sign of the parameter not the appropriate way to proceed, we consider instead prediction of the sign of the score component for the parameter at zero, obtaining a method that is related to classical score tests on variance components.