bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiation exposure to personnel performing endoscopic retrograde cholangiopancreatography
Authors: Naidu L S , Singhal S , Preece D E , Vohrah A , Loft D E 
Published: October 2005

Abstract

Background
Endoscopic retrograde cholangiopancreatography (ERCP) relies on the use of ionising radiation but risks to operator and patient associated with radiation exposure are unclear. The aim of this prospective study was to estimate the radiation dose received by personnel performing fluoroscopic endoscopic procedures, mainly ERCP.

Methods
Consecutive procedures over a two month period were included. The use of thermoluminescent dosimeters to measure radiation exposure to the abdomen, thyroid gland, and hands of the operator permitted an estimation of the annual whole body effective dose equivalent.

Results
During the study period 66 procedures (61 ERCP) were performed and the estimated annual whole body effective dose equivalent received by consultant operators ranged between 3.35 and 5.87 mSv. These values are similar to those received by patients undergoing barium studies and equate to an estimated additional lifetime fatal cancer risk between 1 in 7000 and 1 in 3500. While within legal safety limits for radiation exposure to personnel, these doses are higher than values deemed acceptable for the general public.

Conclusions
It is suggested that personnel as well as patients may be exposed to significant values of radiation during ERCP. The study emphasises the need to carefully assess the indication for, and to use measures that minimise radiation exposure during any fluoroscopic procedure.
Vulnerability of Southwest Iberian amphibians to an introduced crayfish, Procambarus clarkii
Authors: Rebelo Rui , Cruz Maria João 
Published: October 2005

AbstractThe introduction of predators in amphibian breeding habitats may contribute to the decline or extinction of amphibian populations. Procambarus clarkii, a North American crayfish, was recently introduced in the Iberian Peninsula, being now quite abundant in the southwest, a region with no native crayfish species and where 13 amphibian species may be found. We performed mesocosm experiments to evaluate the vulnerability of amphibian embryos and larvae from those species to P. clarkii. Despite the presence of alternative food (vegetation and leaf litter), embryo survival in the presence of P. clarkii was low for all species except Bufo bufo. However, newly hatched B. bufo tadpoles were readily consumed. P. clarkii reduced larval survival in all species, with those species that in nature have few contacts with predators at the larval stage suffering the highest mortalities. Most larvae reduced their activity and/or altered microhabitat use in the presence of P. clarkii, but these behavioural modifications did not lead necessarily to a low vulnerability to predation.
Phylogeny and evolution of the green lizards, Lacerta spp. (Squamata: Lacertidae) based on mitochondrial and nuclear DNA sequences
Authors: Godinho Raquel , Crespo Eduardo , Ferrand Nuno , Harris D. James 
Published: October 2005

AbstractPartial DNA sequences from three mitochondrial (cytochrome b, 12S rRNA and 16S rRNA) and two nuclear (β-fibrinogen intron 7 and C-mos) genes were used to estimate the phylogenetic relationships among all eight extant species of green lizards, Lacerta sensu stricto, and many currently recognized subspecies. All eight species form a monophyletic group. L. agilis, L. schreiberi and L. strigata are genetically well differentiated species. L. trilineata and L. pamphylica are not monophyletic units based on analyses of the β-fibrinogen intron 7. Lacerta media is closely related to some Lacerta trilineata. L. bilineata and L. viridis are closely related, and recognition of L. bilineata as a distinct species makes L. viridis paraphyletic also. For both L. bilineata and L. viridis, some subspecies appear to remain in their southern glacial refugia, while a single genetic entity shows successfully postglacial expansion. The topology derived from C-mos variation is concordant with that derived from mtDNA, with substitutions occurring at a similar rate to that of transversions in the rRNA genes. Although C-mos is typically used at deeper taxonomic levels it is also phylogenetically informative within green lizards. β-fibrinogen intron 7, typically used for assessing phylogenetic relationships among bird species, is a useful phylogenetic marker for reptiles also, showing considerable variation between species. There is not complete concordance between estimates of relationships derived from the mtDNA and nuclear markers, probably because rapid diversification led to incomplete lineage sorting in the green lizards. Introgression could also be occuring between some species.
Soil Control on Runoff Response to Climate Change in Regional Climate Model Simulations
Authors: van den Hurk Bart , Hirschi Martin , Schär Christoph , Lenderink Geert , van Meijgaard Erik , van Ulden Aad , Rockel Burkhardt , Hagemann Stefan , Graham Phil , Kjellström Erik , Jones Richard 
Published: October 2005

Abstract
Simulations with seven regional climate models driven by a common control climate simulation of a GCM carried out for Europe in the context of the (European Union) EU-funded Prediction of Regional scenarios and Uncertainties for Defining European Climate change risks and Effects (PRUDENCE) project were analyzed with respect to land surface hydrology in the Rhine basin. In particular, the annual cycle of the terrestrial water storage was compared to analyses based on the 40-yr ECMWF Re-Analysis (ERA-40) atmospheric convergence and observed Rhine discharge data. In addition, an analysis was made of the partitioning of convergence anomalies over anomalies in runoff and storage. This analysis revealed that most models underestimate the size of the water storage and consequently overestimated the response of runoff to anomalies in net convergence. The partitioning of these anomalies over runoff and storage was indicative for the response of the simulated runoff to a projected climate change consistent with the greenhouse gas A2 Synthesis Report on Emission Scenarios (SRES). In particular, the annual cycle of runoff is affected largely by the terrestrial storage reservoir. Larger storage capacity leads to smaller changes in both wintertime and summertime monthly mean runoff. The sustained summertime evaporation resulting from larger storage reservoirs may have a noticeable impact on the summertime surface temperature projections.
Mechanisms of Decadal Arctic Climate Variability in the Community Climate System Model, Version 2 (CCSM2)
Authors: Goosse Hugues , Holland Marika M. 
Published: October 2005

Abstract
Several mechanisms have been proposed to explain natural climate variability in the Arctic. These include processes related to the influence of the North Atlantic Oscillation/Arctic Oscillation (NAO/AO), anticyclonic/cyclonic regimes, changes in the oceanic and atmospheric North Atlantic–Arctic exchange, and changes in the Atlantic meridional overturning circulation. After a brief critical review, the influence and interrelation of the above processes in a long climate integration of the Community Climate System Model, version 2 (CCSM2) are examined. The analysis is based on the time series of surface air temperature integrated northward of 70°N, which serves as a useful proxy for general Arctic climate conditions. This gives a large-scale view of the evolution of Arctic climate. It is found that changes in oceanic exchange and heat transport in the Barents Sea dominate in forcing the Arctic surface air temperature variability in CCSM2. Changes in atmospheric circulation are consistent with a wind forcing of this variability, while changes in the deep overturning circulation in the Atlantic are more weakly related in CCSM2. Over some time periods, the NAO/AO is significantly related to these changes in Arctic climate conditions. However, this is not robust over longer time scales.
Integrating Ocean Subsurface Temperatures in Statistical ENSO Forecasts
Authors: Ruiz Jose Eric , Cordery Ian , Sharma Ashish 
Published: October 2005

Abstract
Subsurface characteristics of oceans have recently become of interest to climate modelers. Here subsurface information has been linked to the evolution of the El Niño–Southern Oscillation (ENSO) in a simple statistical formulation. The hypothesis proposed is that the inclusion of subsurface ocean heat content in a persistence-based representation of ENSO results in an increase in prediction skill. The subsurface temperature field is represented by anomalies in the 20°C isotherm (Z20) in the Indian and Pacific Oceans. Using a cross-validation approach, the first two empirical orthogonal functions (EOFs) of the Z20 anomalies are derived, but only the second EOF is used as a predictor. The first EOF is found to be representative of the mature ENSO signal while the second EOF shows characteristics that are precursory to an ENSO event. When included in a persistence-based prediction scheme, the second EOF enhances the skill of ENSO hindcasts up to a lead time of 15 months. Results are compared with another model that uses the second EOF of the SST anomalies in the tropical Pacific Ocean and persistence as predictors. Cross-validated hindcasts from the isotherm-based scheme are generally more skillful than those obtained from the persistence and SST-based prediction schemes. Hindcasts of cold events are particularly close to the observed values even at long lags. Major improvements occur for predictions made during boreal winter and spring months when the addition of subsurface information resulted in predictions that are not greatly affected by the damping effect of the “spring barrier.”
Two Independent Triggers for the Indian Ocean Dipole/Zonal Mode in a Coupled GCM
Authors: Fischer Albert S. , Terray Pascal , Guilyardi Eric , Gualdi Silvio , Delecluse Pascale 
Published: October 2005

Abstract
The question of whether and how tropical Indian Ocean dipole or zonal mode (IOZM) interannual variability is independent of El Niño–Southern Oscillation (ENSO) variability in the Pacific is addressed in a comparison of twin 200-yr runs of a coupled climate model. The first is a reference simulation, and the second has ENSO-scale variability suppressed with a constraint on the tropical Pacific wind stress. The IOZM can exist in the model without ENSO, and the composite evolution of the main anomalies in the Indian Ocean in the two simulations is virtually identical. Its growth depends on a positive feedback between anomalous equatorial easterly winds, upwelling equatorial and coastal Kelvin waves reducing the thermocline depth and sea surface temperature off the coast of Sumatra, and the atmospheric dynamical response to the subsequently reduced convection.
Two IOZM triggers in the boreal spring are found. The first is an anomalous Hadley circulation over the eastern tropical Indian Ocean and Maritime Continent, with an early northward penetration of the Southern Hemisphere southeasterly trades. This situation grows out of cooler sea surface temperatures in the southeastern tropical Indian Ocean left behind by a reinforcement of the late austral summer winds. The second trigger is a consequence of a zonal shift in the center of convection associated with a developing El Niño, a Walker cell anomaly. The first trigger is the only one present in the constrained simulation and is similar to the evolution of anomalies in 1994, when the IOZM occurred in the absence of a Pacific El Niño state. The presence of these two triggers—the first independent of ENSO and the second phase locking the IOZM to El Niño—allows an understanding of both the existence of IOZM events when Pacific conditions are neutral and the significant correlation between the IOZM and El Niño.
Effects of Secular Changes in Frequency of Observations and Observational Errors on Monthly Mean MSLP Summary Statistics Derived from ICOADS
Authors: Chang Edmund K. M. 
Published: October 2005

Abstract
A Monte Carlo technique has been employed to assess how sextile mean sea level pressure (MSLP) statistics derived from ship observations can be affected by changes in the frequency of observations. The results show that when the number of observations is small (less than 20 per month), the estimates of the first sextile as well as the intersextile range, which is considered to be a resistant estimate of the standard deviation, can contain large biases. The results also suggest that, while changes in the frequency of observations do not have strong impacts on the standard way of estimating the standard deviation, such statistics are strongly affected by secular trends in observational error statistics.
The results are applied to examine the increasing trend in cool season (December–March) Pacific cyclone activity during the second half of the twentieth century. The results show that the trends in sextile statistics derived from the NCEP–NCAR reanalysis data are only consistent with those derived from the International Comprehensive Ocean–Atmosphere Data Set (ICOADS) summary statistics if biases due to changes in the frequency of observation are not taken into account. When such biases are accounted for, the trends derived from the observations are significantly smaller than those derived from the reanalysis data. As for the increasing trend in MSLP variance, the trends derived from the ICOADS statistics are smaller than those derived from the reanalysis regardless of whether corrections are made to account for the secular trend in MSLP error statistics. In either case, the corrections that have to be applied have the same order of magnitude as the observed trends.
The two main conclusions are that 1) climate statistics can be strongly affected by changes in frequency of observations as well as changes in observational error statistics and 2) the trends in North Pacific winter cyclone activity, as derived from NCEP–NCAR reanalysis data, appear to be significantly larger than similar trends computed from ICOADS sextile and variance statistics, when biases due to changes in frequency of observations and observational error statistics have been taken into account.
Effect of Preconditioning on the Extreme Climate Events in the Tropical Indian Ocean*
Authors: Annamalai H. , Potemra J. , Murtugudde R. , McCreary J. P. 
Published: October 2005

Abstract
Sea surface temperature observations in the eastern equatorial Indian Ocean (EEIO) during the period 1950–2003 indicate that Indian Ocean dipole/zonal mode (IODZM) events are strong in two decades, namely, the 1960s and 1990s. Atmospheric reanalysis products in conjunction with output from an ocean model are examined to investigate the possible reason for the occurrence of strong IODZM events in these two decades. Specifically, the hypothesis that the mean thermocline in the EEIO is raised or lowered depending on the phase of Pacific decadal variability (PDV), preconditioning the EEIO to favor stronger or weaker IODZM activity, is examined. Diagnostics reveal that the EEIO is preconditioned by the traditional PDV signal (SVD1 of SST), deepening or shoaling the thermocline off south Java through its influence on the Indonesian Throughflow (ITF; oceanic teleconnection), and by residual decadal variability in the western and central Pacific (SVD2 of SST) that changes the equatorial winds over the Indian Ocean (atmospheric teleconnection). Both effects produce a background state that is either favorable or unfavorable for the thermocline–mixed layer interactions, and hence for the excitation of strong IODZM events. Collectively, SVD1 and SVD2 are referred to as PDV here.
This hypothesis is tested with a suite of ocean model experiments. First, two runs are carried out, forced by climatological winds to which idealized easterly or westerly winds are added only over the equatorial Indian Ocean. As might be expected, in the easterly (westerly) run a shallower (deeper) thermocline is obtained over the EEIO. Then, observed winds from individual years are used to force the model. In these runs, anomalously cool SST in the EEIO develops only during decades when the thermocline is anomalously shallow, allowing entrainment of colder waters into the mixed layer.
Since 1999 the PDV phase has changed, and consistent with this hypothesis the depth of the mean thermocline in the EEIO has been increasing. As a consequence, no IODZM developed during the El Niño of 2002, and only a weak cooling event occurred during the summer of 2003. This hypothesis likely also explains why some strong IODZM events occur in the absence of ENSO forcing, provided that PDV has preconditioned the EEIO thermocline to be anomalously shallow.
A Cautionary Note on the Use of Error Bars
Authors: Lanzante John R. 
Published: October 2005

Abstract
Climate studies often involve comparisons between estimates of some parameter derived from different observed and/or model-generated datasets. It is common practice to present estimates of two or more statistical quantities with error bars about each representing a confidence interval. If the error bars do not overlap, it is presumed that there is a statistically significant difference between them. In general, such a procedure is not valid and usually results in declaring statistical significance too infrequently. Simple examples that demonstrate the nature of this pitfall, along with some formulations, are presented. It is recommended that practitioners use standard hypothesis testing techniques that have been derived from statistical theory rather than the ad hoc approach involving error bars.
Top-of-Atmosphere Direct Radiative Effect of Aerosols over Global Oceans from Merged CERES and MODIS Observations
Authors: Loeb Norman G. , Manalo-Smith Natividad 
Published: October 2005

Abstract
The direct radiative effect of aerosols (DREA) is defined as the difference between radiative fluxes in the absence and presence of aerosols. In this study, the direct radiative effect of aerosols is estimated for 46 months (March 2000–December 2003) of merged Clouds and the Earth’s Radiant Energy System (CERES) and Moderate Resolution Imaging Spectroradiometer (MODIS) Terra global measurements over ocean. This analysis includes the contribution from clear regions in both clear and partly cloudy CERES footprints. MODIS–CERES narrow-to-broadband regressions are developed to convert clear-sky MODIS narrowband radiances to broadband shortwave (SW) radiances, and CERES clear-sky angular distribution models (ADMs) are used to estimate the corresponding top-of-atmosphere (TOA) radiative fluxes that are needed to determine the DREA. Clear-sky MODIS pixels are identified using two independent cloud masks: (i) the NOAA/National Environmental Satellite, Data, and Information Service (NESDIS) algorithm that is used for inferring aerosol properties from MODIS on the CERES Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product (NOAA SSF); and (ii) the standard algorithm that is used by the MODIS aerosol group to produce the MODIS aerosol product (MOD04). Over global oceans, direct radiative cooling by aerosols for clear scenes that are identified from MOD04 is estimated to be 40% larger than for clear scenes from NOAA SSF (5.5 compared to 3.8 W m−2). Regionally, differences are largest in areas that are affected by dust aerosol, such as oceanic regions that are adjacent to the Sahara and Saudi Arabian deserts, and in northern Pacific Ocean regions that are influenced by dust transported from Asia. The net total-sky (clear and cloudy) DREA is negative (cooling) and is estimated to be −2.0 W m−2 from MOD04, and −1.6 W m−2 from NOAA SSF. The DREA is shown to have pronounced seasonal cycles in the Northern Hemisphere and large year-to-year fluctuations near deserts. However, no systematic trend in deseasonalized anomalies of the DREA is observed over the 46-month time series that is considered.
Gender Composition and Group Cohesion in U.S. Army Units: A Comparision across Five Studies
Authors: Rosen Leora N. , Bliese Paul D. , Wright Kathleen A. , Gifford Robert K. 
Published: October 2005

The purpose of this study was to examine the relationship between gender composition and group cohesion in U.S. Army combat support and combat service support units. Five studies were compared in this analysis, including survey data obtained in the Persian Gulf during Operation Desert Storm; in Somalia during Operation Restore Hope; in Haiti during Operation Uphold Democracy; and in two garrison samples. A higher percentage of women in the unit was strongly associated with lower horizontal cohesion in the Somalia sample, and there was a much smaller association between these variables in the Persian Gulf sample. This relationship was present only among junior enlisted soldiers in one of the garrison surveys but was absent in the other garrison survey and in the Haiti sample. In most cases, a higher percentage of women was associated with lower cohesion. Possible reasons for differences across studies in the strength of the association may include gender differences in support for the mission and differences in deployment circumstances.
Adapting the randomized consent (Zelen) design for trials of behavioural interventions for chronic disease: feasibility study
Authors: Campbell Rona , Peters Tim , Grant Clare , Quilty Brian , Dieppe Paul 
Published: October 2005

Objectives: Standard randomized controlled trials of interventions for chronic conditions that involve behavioural change, or that are highly desired by participants, are difficult to undertake because of problems with recruitment and contamination. Alternatives include cluster-randomized trials or pre-randomization designs such as the Zelen design. The aim here was to develop a pre-randomization design that would overcome ethical and methodological problems associated with the conventional Zelen design, and permit the rigorous evaluation of a complex package of care, involving physical therapy and behavioural changes, for patients with painful patello-femoral osteoarthritis of the knee joint. Methods: Eligible patients were first consented to a one-year observational study of their arthritis. They were subsequently randomized into intervention and control arms. Those in the intervention arm were then asked if they were willing to participate in a further study involving regular sessions with a physiotherapist. Those in the control arm were not told about this, but were followed up as agreed. Results: Eighty-seven patients consented to the observational study, 43 of whom were subsequently randomized to the intervention arm. All 43 consented to the intervention, although five of these did not receive the full package of care. Assessments were carried out at five months and one year on 82 patients, and concealment was satisfactorily maintained in the majority. Conclusions: We conclude that this study design could potentially offer an acceptable compromise between the need for scientific rigour and the ethical imperative of fully informed consent in trials that involve behavioural change or interventions that patients might want to obtain.