bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stellar populations of disc galaxies: from the center of the bulge to the edge of the disc
Authors: Morelli L. , Pompei E. , Pizzella A. , Coccato L. , Corsini E. M. , Mendez Abreu J. , Saglia R. , Sarzi M. , Bertola F. 
Published: April 2010

AbstractWe present extensive photometric and spectroscopic study to give a new insight in the bulge stellar population. Super-solar α/Fe and its constant value along the radial profile, in most of the galaxies, suggest that the star formation in these objects has been fast and occurred at the same time in the whole bulge.
Young Stellar Populations in the Collisional Ring Galaxy NGC 922
Authors: Pellerin A. , Meurer G. R. , Bekki K. , Elmegreen D. M. , Wong O. I. , Knezek P. 
Published: April 2010

AbstractWe studied the star cluster population properties in the nearby collisional ring galaxy NGC 922 using HST/WFPC2 photometry and population synthesis modeling. We found that 69% of the detected clusters are younger than 7 Myr, and that most of them are located in the ring or along the bar, consistent with the strong Hα emission. The images also show a tidal plume pointing toward the companion. Its stellar age is consistent with pre-existing stars that were probably stripped off during the passage of the companion. We compared the star-forming complexes observed in NGC 922 with those of a distant ring galaxy from the GOODS eld. It indicates very similar masses and sizes, suggesting similar origins. Finally, we found clusters that are excellent progenitor candidates for faint fuzzy clusters.
Control sample for galaxy pairs: Simulations and Observations
Authors: Perez Josefa , Tissera Patricia 
Published: April 2010

AbstractSeveral attempts have been made in order to isolate the effect of galaxy interactions by comparing galaxy in pairs with isolated galaxies. However, different authors have proposed different ways to build these control samples (CS). By using mock galaxy catalagues built up from the Millennium Simulation, we show that the set of constrains used to define a CS might introduce biases which could affect the interpretation of results. In this analysis, we make use of the fact that the physics of interactions is not included in the semi-analytic model, so that any difference between the mock control and pair samples can be attributed to selection biases. Thus, we suggest how to build an unique and unbiased CS in order to individualize the effect of interactions. Based on this theoretical findings and using the SDSS-DR4 data, we revise some previous observational results of galaxy in pairs in order to evaluate any possible disagreement. The comparison between simulations and observations suggests an overestimated effect of the DM halo bias in semianalytical models.
Abundance Patterns Among Very Metal-Poor Stars in the Halo of the Galaxy: A Statistical Approach
Authors: Placco Vinicius M. , Rossi Silvia , Beers Timothy C. , Lucatello Sara 
Published: April 2010

AbstractThe main goal of this work is to explore the abundance patterns of the very metal-poor stars ([Fe/H]<−2.0) observed by the HERES (Hamburg ESO R-process Enhanced Star - Christlieb et al. 2004) survey. This type of study allows the analysis of the correlations among chemical elements, and place some constraints on the operation of the neutron-capture (r and s) processes in the early Galaxy. This approach makes use of statistical tools, such as agglomerative nesting, which can identify the formation of natural groups based on relations among elemental abundances (e.g. [C/Fe], [Sr/Fe], [Ba/Fe], and [Eu/Fe]), and can also be used in a series of “large-sample like” studies.This study provides a comprehensive analysis of a sample of 326 metal-poor stars, and introduces two new subclasses (r-0 and s-I) for metal-poor stars with determined abundances of neutron-capture elements, aiming to standardize the nomenclature for those objects and, by reproducing previous results, confirms the validity of the statistical method used.
Stellar populations in Luminous Red Galaxies: cosmic chronometers?
Authors: Ratsimbazafy A. L. , Cress C. M. , Blyth S. L. , Crawford S. M. , Olivier E. A. , van der Heyden K. J. 
Published: April 2010

AbstractThe expansion rate of the Universe can potentially be measured using age-dating of Luminous Red Galaxies (LRGs). Here, we explore the validity of the assumptions implicit in this method using LRGs identified in the Millenium Simulation (MS). We use stellar population modelling and spectral synthesis to estimate the errors on ages that can be expected and discuss optimization of such an experiment. We find that H(z) using simulated galaxies from MS can be recovered with high accuracy. Using single stellar populations (SSPs) to age-date LRGs is not sufficient but if the MS star formation histories of galaxies are used, accurate ages are obtainable. We discuss an observing program to carry out this experiment using SALT (Southern African Large Telescope).
Stellar Populations in Barred Galaxies
Authors: Robert C. , Cantin S. , Mollá M. , Pellerin A. , Brière É. 
Published: April 2010

AbstractWe developed an iterative technique to better characterize stellar populations and the central activity of barred galaxies using evolutionary synthesis codes and OASIS data. The case of NGC 5430 is presented here. Our results are reinforcing the role played by the bar and nuclear structures for the evolution of galaxies.
The Apache Point Observatory Galactic Evolution Experiment (APOGEE)
Authors: Schiavon Ricardo P. , Majewski Steven R. 
Published: April 2010

AbstractThe Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a large scale, high-resolution, near-infrared spectroscopic survey of Milky Way stellar populations and one of the four experiments in the Sloan Digital Sky Survey III (SDSS-III). APOGEE will be based on a new multi-fiber cryogenic spectrograph, currently under construction, expected to begin survey observations on the 2.5 m Sloan telescope in the Spring of 2011. APOGEE will measure high-precision radial velocities and elemental abundances for ~15 elements for ~ 105 stars, and is expected to shed new light on the processes that led to the formation of the Galaxy.
Star-forming regions in the intragroup medium of compact groups of galaxies
Authors: Torres-Flores S. , Mendes de Oliveira C. , de Mello D. F. , Amram P. , Plana H. , Epinat B. , Iglesias-Páramo J. 
Published: April 2010

AbstractWe present the results of a multiwavelength campaign searching for young objects in the intragroup medium of seven compact groups of galaxies: HCG 2, 7, 22, 23, 92, 100 and NGC 92. We used Fabry-Perot velocity fields and rotation curves together with GALEX NUV and FUV images, optical R-band and HI maps to evaluate the stage of interaction of each group. We conclude that groups (i) HCG 7 and HCG 23 are in an early stage of interaction, (ii) HCG 2 and HCG 22 are mildly interacting, and (iii) HCG 92, HCG 100 and NGC 92 are in a late stage of evolution. Evolved groups have a population of young objects in their intragroup medium while no such population is found within the less evolved groups. We also report the discovery of a tidal dwarf galaxy candidate in the tail of NGC 92. These three groups, besides containing galaxies which have peculiar velocity fields, also show extended HI tails. Our results indicate that the advanced stage of evolution of a group together with the presence of intragroup HI clouds may lead to star formation in the intragroup medium.
Stellar formation in Brightest Cluster Galaxies
Authors: Zapata Pichinao Tatiana , Lima Neto Gastão B. 
Published: April 2010

AbstractWe study the interplay between stellar population of the Brightest Cluster Galaxies (BCG) and cluster global properties. We use X-ray properties from Chandra, ROSAT and ASCA observations and BCGs spectra from SDSS-DR6. Using STARLIGHT we determined the star formation history of the BCGs and look for relations with the intra-cluster gas properties. Our first results show no correlation between the recent star formation with x-ray temperature and dynamic state. An important star formation is happening in cool-core Cluster. This new stellar population has low metallicity, pointing to an external source of cold gas to form stars.
SFHs Across the Merging Disks of Arp 244 – from FUV to MIR
Authors: Zhang Hong-Xin , Gao Yu , Kong Xu 
Published: April 2010

AbstractIncluding MIPS 24 μm dust emission in the multi-band stellar population analysis, we roughly constrain the star formation histories (SFHs) of MIPS 24 μm selected star-forming regions across the merging disks of the Antennae galaxies. While the overlap regions hold the highest ratios of young over intermediate populations, the western-loop regions have the highest ratios of intermediate to old populations. We find two sequential star formation (SF) paths in the overlap regions, which we interpret as the imprint of the interpenetrating process of the two merging disks following their second close encounter.
Permutation importance: a corrected feature importance measure
Authors: Altmann André , Toloşi Laura , Sander Oliver , Lengauer Thomas 
Published: April 2010

Abstract
Motivation: In life sciences, interpretability of machine learning models is as important as their prediction accuracy. Linear models are probably the most frequently used methods for assessing feature relevance, despite their relative inflexibility. However, in the past years effective estimators of feature relevance have been derived for highly complex or non-parametric models such as support vector machines and RandomForest (RF) models. Recently, it has been observed that RF models are biased in such a way that categorical variables with a large number of categories are preferred.
Results: In this work, we introduce a heuristic for normalizing feature importance measures that can correct the feature importance bias. The method is based on repeated permutations of the outcome vector for estimating the distribution of measured importance for each variable in a non-informative setting. The P-value of the observed importance provides a corrected measure of feature importance. We apply our method to simulated data and demonstrate that (i) non-informative predictors do not receive significant P-values, (ii) informative variables can successfully be recovered among non-informative variables and (iii) P-values computed with permutation importance (PIMP) are very helpful for deciding the significance of variables, and therefore improve model interpretability. Furthermore, PIMP was used to correct RF-based importance measures for two real-world case studies. We propose an improved RF model that uses the significant variables with respect to the PIMP measure and show that its prediction accuracy is superior to that of other existing models.
Availability: R code for the method presented in this article is available at http://www.mpi-inf.mpg.de/∼altmann/download/PIMP.R
Contact: altmann@mpi-inf.mpg.de, laura.tolosi@mpi-inf.mpg.de
Supplementary information: Supplementary data are available at Bioinformatics online.
Multi-objective tag SNPs selection using evolutionary algorithms
Authors: Ting Chuan-Kang , Lin Wei-Ting , Huang Yao-Ting 
Published: April 2010

Abstract
Motivation: Integrated analysis of single nucleotide polymorphisms (SNPs) and structure variations showed that the extent of linkage disequilibrium is common across different types of genetic variants. A subset of SNPs (called tag SNPs) is sufficient for capturing alleles of bi-allelic and even multi-allelic variants. However, accuracy and power of tag SNPs are affected by several factors, including genotyping failure, errors and tagging bias of certain alleles. In addition, different sets of tag SNPs should be selected for fulfilling requirements of various genotyping platforms and projects.
Results: This study formulates the problem of selecting tag SNPs into a four-objective optimization problem that minimizes the total amount of tag SNPs, maximizes tolerance for missing data, enlarges and balances detection power of each allele class. To resolve this problem, we propose evolutionary algorithms incorporated with greedy initialization to find non-dominated solutions considering all objectives simultaneously. This method provides users with great flexibility to extract different sets of tag SNPs for different platforms and scenarios (e.g. up to 100 tags and 10% missing rate). Compared to conventional methods, our method explores larger search space and requires shorter convergence time. Experimental results revealed strong and weak conflicts among these objectives. In particular, a small number of additional tag SNPs can provide sufficient tolerance and balanced power given the low missing and error rates of today's genotyping platforms.
Availability: The software is freely available at Bioinformatics online and http://cilab.cs.ccu.edu.tw/service_dl.html
Contact: ckting@cs.ccu.edu.tw; ythuang@cs.ccu.edu.tw
The association between long‐term longitudinal trends in guideline adherence and mortality in relation to age and sex
Authors: Frankenstein Lutz , Remppis Andrew , Fluegel Andrea , Doesch Andreas , Katus Hugo A. , Senges Jochen , Zugck Christian 
Published: April 2010

AimsUsing a large clinical multi‐site prospective chronic heart failure registry, we sought to determine (i) implementation of guidelines over time and (ii) adjusted survival benefit there from.Methods and resultsClinical characteristics, mortality, and medication according to guidelines [guideline adherence index (GAI) for ACE‐inhibitors or angiotensin receptor blockers, beta‐blockers, aldosterone antagonists] were compared for 1481 patients included from 1994 to 2000 and 1811 patients from 2001 to 2007. The co‐morbidity corrected GAI significantly increased from 1994–2000 to 2001–07 (P < 0.001). Concomitantly, 1‐ and 3‐year mortality decreased (14.1–4.8 and 29.5–10.9%, respectively, P < 0.001 each). No interaction with age or sex was noted (P = 0.06, P = 0.25, respectively), though age determined complete medication according to guidelines (P < 0.05). The GAI was a significant predictor of lower overall mortality (adjusted HR per 10% increase: 0.92; 95% CI: 0.88–0.97; P = 0.001), again independent from age or sex. Results were essentially unchanged after controlling for co‐morbidities and other potential confounders.ConclusionThis study shows that increased use of medication according to guidelines might occur without interventions targeting medication use. It seems to be associated with a substantial improvement in survival. Even though causality cannot be proven, the findings underscore the importance of meticulous implementation of guidelines irrespective of age, sex, or co‐morbidities.
Horizontal movements of simulated escaped farmed Atlantic salmon (Salmo salar) in a western Norwegian fjord
Authors: Skilbrei Ove T. , Holst Jens Christian , Asplin Lars , Mortensen Stein 
Published: April 2010

Abstract
Skilbrei, O. T., Holst, J. C., Asplin, L., and Mortensen, S. 2010. Horizontal movements of simulated escaped farmed Atlantic salmon (Salmo salar) in a western Norwegian fjord. – ICES Journal of Marine Science, 67: 1206–1215. The dispersal of simulated escaped farmed Atlantic salmon (Salmo salar) in Hardangerfjord in western Norway was studied by telemetry. Tagged fish were released from fish farms on five different dates in the course of 1 year. Irrespective of the time of year, the fish dispersed rapidly, with a mean displacement from the release site of 5–7 km after 1 d, and 9–12 km after 2 d. Individual rates of movement varied, but were much higher than the rate of displacement from the release site, as fish moved around in the fjord basin in all directions. As a result, the fish were spread over an area of more than 500 km2 after 1 week. The number of released fish recorded in the fjord gradually declined after each release from ∼40% remaining in the fjord after 3 weeks to few or none after 7 weeks. In all, 38% moved out of the fjord, and 36 and 2% were reported as captured inside and outside the fjord, respectively. Their rapid dispersal suggests that concentrating efforts to recapture escaped salmon in the proximity of an escape site will probably not be successful, at least from locations of this type. In fact, the recaptures demonstrate that it is both necessary and possible to expand the fishing effort to cover a large area and to sustain it for several weeks to attain high rates of recapture. The wide dispersal of escaped fish potentially acting as vectors within the fjord basin also has implications for the spread of disease and parasites.
Dietary phosphorus availability influences female cricket lifetime reproductive effort
Authors: VISANUVIMOL LAKSANAVADEE , BERTRAM SUSAN M. 
Published: April 2010

1. Recent ecological stoichiometric findings indicate that the relationships among key macronutrient elements [e.g. carbon (C), nitrogen (N), and phosphorus (P) of organisms and their resources] may underlie variation in life‐history traits. The amount of phosphorus in an individual's body is often correlated with its rate of growth, and low‐phosphorus diets are known to reduce growth in a number of insect and crustacean herbivores.2. These findings suggest that the stoichiometric imbalance between organismal biomass requirements and the relative scarcity of nutrients in nature may also underlie variation in lifetime reproductive success.3. This study investigated how dietary phosphorus availability during adulthood influenced lifetime reproductive effort, compensatory feeding, lifespan, condition, and stoichiometry of adult European House Cricket, Acheta domesticus.4. Female crickets fed high amounts of phosphorus during adulthood laid significantly more eggs compared to those fed low amounts of phosphorus. Phosphorus availability did not directly influence lifespan, condition, or body stoichiometry, and crickets did not compensate for low phosphorus diets by eating more food.5. A stoichiometric perspective may help understand the causes of variation in invertebrate fitness.
Functional indicators of stream health: a river‐basin approach
Authors: FEIO M. J. , ALVES T. , BOAVIDA M. , MEDEIROS A. , GRAÇA M. A. S. 
Published: April 2010

Summary1. The efficacy of leaf‐litter decomposition, sediment respiration, biofilm biomass, growth, chlorophyll a concentration and the autotrophic index (biofilm ash‐free dry mass/chlorophyll a) and fungal biomass for detecting human‐induced change was evaluated using 24 references and 15 disturbed stream sites located in central Portugal.2. Decomposition rates of alder (Alnus glutinosa) and oak (Quercus robur) leaves and sediment respiration rates were effective in discriminating impairment. Decomposition was negatively correlated with abiotic factors, such as ammonium and nitrite concentrations, connectivity and alterations in the hydrological regime, and positively correlated with nitrate concentration and oxygen concentration. Sediment respiration rates were correlated with organic contamination, land use and morphological changes.3. Growth rates of biofilm, concentration of chlorophyll a and the autotrophic index, although 41–73% higher at disturbed compared to reference sites, were not significantly different. These three variables were significantly correlated with total organic carbon, oxygen concentration, pH, nitrite and the presence of dams. Fungal biomass on leaves and biofilm biomass on natural substrata did not differ between reference and disturbed sites.4. Our findings lend support to the use of functional variables like decomposition and sediment respiration in monitoring and when used together with structural variables should give a more holistic measure of stream health.
Fracture resistance of root filled molar teeth restored with glass fibre bundles
Authors: Rodrigues F. B. , Paranhos M. P. G. , Spohr A. M. , Oshima H. M. S. , Carlini B. , Burnett Jr L. H. 
Published: April 2010

Rodrigues FB, Paranhos MPG, Spohr AM, Oshima HMS, Carlini B, Burnett LH Jr. Fracture resistance of root filled molar teeth restored with glass fibre bundles. International Endodontic Journal, 43, 356–362, 2010.AbstractAim  To evaluate the effect of unidirectional or woven glass fibre tapes inserted into MOD cavity preparations on the fracture resistance of root filled molar teeth.Methodology  Extracted human molar teeth were randomly divided into six groups (n = 15) : G1 – sound teeth, control; G2 – MOD cavity preparation; G3 – MOD + root canal treatment (Endo); G4 – MOD + Endo + composite resin restoration (Resin); G5 – MOD + Endo + unidirectional fibre (UF) + Resin; G6 – MOD + ;Endo + woven fibre (WF) + Resin. The teeth were subjected to a compressive fracture test in a universal testing machine. After testing, two failure modes were classified: pulp chamber floor or cusp.Results  The highest and the lowest mean fracture strengths were found in sound teeth (G1) (4960N) and MOD + root canal treatment (G3) (612.84N), respectively, with significant differences from the other groups (P < 0.05). The remaining groups had statistically similar means. In G5 and G6, there was a tendency for fracture to occur in the pulp chamber floor compromising tooth integrity.Conclusions  The insertion of glass fibres into MOD cavity preparations and restoring them with composite resin was not different than molar teeth filled with composite resin only in terms of fracture resistance. Fibres placed into MOD cavities do not reinforce teeth.
Transdentinal stimulation of tertiary dentine formation and intratubular mineralization by growth factors
Authors: Kalyva M. , Papadimitriou S. , Tziafas D. 
Published: April 2010

Kalyva M, Papadimitriou S, Tziafas D. Transdentinal stimulation of tertiary dentine formation and intratubular mineralization by growth factors. International Endodontic Journal, 43, 382–392, 2010.AbstractAim  To evaluate the effects of recombinant growth factors on tertiary dentine formation and intratubular mineralization after their application on deep dentinal cavities in dog’s teeth.Methodology  Treatment included dentinal etching (37% phosphoric acid) and applications of bioactive molecules (1 μg mL−1 TGF‐β1, 10 μg mL−1 IGF‐1, 10 μg mL−1 bFGF, 10 μg mL−1 OP‐1 or 1 μg mL−1 monoclonal anti‐human TGF‐β1 in phosphate buffered saline, PBS) at the dentinal base of buccal Class V cavities. Control groups were treated with 0.1% dog serum albumin (DSA) in PBS omitting the growth factors. This was performed both with and without dentinal etching. The dentinal responses regarding tertiary dentine formation and intratubular mineralization were assessed after 3 and 8 weeks, respectively, using light and scanning electron microscopy. Some specimens were also subjected to dentine permeability testing.Results  The group treated with transforming growth factor‐beta1 (TGF‐β1) and, to a lesser extent, the one treated with osteogenic protein‐1 (OP‐1) showed significantly greater (P < 0.05) tertiary dentine formation and intratubular mineralization over an 8‐week period when compared with the control and the other experimental groups. There were no significant differences between groups in reduction in dentine permeability after treatment.Conclusion  Treatment of exposed dentinal tubules with biologically active molecules might induce intratubular mineralization and tertiary dentine formation. Further research is needed to substantiate any clinical benefits as opposed to traditional treatments of exposed dentine so as to provide a scientific base for the clinical regulation of dentine reactions.