bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations and interpretation of solar‐like oscillations in red‐giant stars
Authors: Hekker S. 
Published: November 2010

AbstractOver the past decade the study of solar‐like oscillations in red‐giant stars has developed significantly. Not only the number of red‐giant stars for which solar‐like oscillations have been observed has increased, but the quality of these observations has improved as well. These steps forward were possible thanks to the development of instrumentation to measure radial velocity variations with a precision of the order of m/s, as well as the launch of dedicated space missions, which provide timeseries of data with unprecedented photometric precision. Many more exciting discoveries are to be expected in the (near) future. This article provides an overview of the development of the field over the last decade, discusses difficulties encountered and overcome in interpreting the observational data, and addresses some challenges and opportunities for further research (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inference from adiabatic analysis of solar‐like oscilations in red giants
Authors: Montalbán J. , Miglio A. , Noels A. , Scuflaire R. , Ventura P. 
Published: November 2010

AbstractThe clear detection with CoRoT and Kepler of radial and non‐radial solar‐like oscillations in many red giants paves the way to seismic inferences on the structure of such stars. We present an overview of the properties of the adiabatic frequencies and frequency separations of radial and non‐radial oscillation modes, highlighting how their detection allows a deeper insight into the properties of the internal structure of red giants. In our study we consider models of red giants in different evolutionary stages, as well as of different masses and chemical composition. We describe how the large and small separations computed with radial modes and with non‐radial modes mostly trapped in the envelope depend on the stellar global parameters and evolutionary state, and we compare our theoretical predictions and first Kepler data.Finally, we find that the properties of dipole modes constitute a promising seismic diagnostic of the evolutionary state of red‐giant stars (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Frequency spacings of p‐modes in red giants observed by CoRoT
Authors: Barban C. , Baudin F. , Mosser B. , Goupil M.J. , De Ridder J. , Samadi R. , Weiss W.W. , Auvergne M. , Baglin A. , the CoRoT Red Giant team  
Published: November 2010

AbstractP‐modes observed in red giants are acoustic resonances similar to those observed in the Sun, stochastically excited by turbulent convection. The high‐quality and quasi‐uninterrupted space data obtained by CoRoT allow us to make a big step forward in the study of such oscillations in red giants by increasing significantly the number of stars for which such oscillations can be detected. We present here the data analysis of a sample of red giants observed during the first long run of CoRoT (142 days). Detailed p‐modes properties are estimated with a particular emphasis on the frequency spacings (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure and evolution of pulsating hot subdwarfs
Authors: Kawaler S.D. 
Published: November 2010

AbstractHot subdwarfs are evolved low‐mass stars that have survived core helium ignition and are now in (or recently finished with) the core helium burning stage. At the hot end of the Horizontal Branch (HB), many of these stars are multiperiodic pulsators. These pulsations have revealed details of their global and internal structure, and provide important constraints on the origin of hot HB stars. While many features of their structure deduced from seismic fits have confirmed what we expected from evolutionary considerations, there have been some surprises as well (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
V391 Peg: Identification of the two main pulsation modes from ULTRACAM u′g′r′ amplitudes
Authors: Silvotti R. , Randall S.K. , Dhillon V.S. , Marsh T.R. , Savoury C.D. , Schuh S. , Fontaine G. , Brassard P. 
Published: November 2010

AbstractV391 Peg (HS 2201+2610) is an extreme horizontal branch subdwarf B (sdB) star, it is an hybrid pulsator showing p‐ and g‐mode oscillations, and hosts a 3.2/sin i MJup planet at an orbital distance of about 1.7 AU. In order to improve the characterization of the star, we measured the pulsation amplitudes in the u′g′r′ Sloan photometric bands using ULTRACAM at the William Herschel 4.2 m telescope and we compared them with theoretical values. The preliminary results presented in this article conclusively show that the two main pulsation periods at 349.5 and 354.1 s are a radial and a dipole mode respectively. This is the first time that the degree index of multiple modes has been uniquely identified for an sdB star as faint as V391 Peg (B = 14.4), proving that multicolor photometry is definitely an efficient technique to constrain mode identification, provided that the data have a high enough quality (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical study of γ Doradus pulsations in pre‐main sequence stars
Authors: Bouabid M.‐P. , Montalbán J. , Miglio A. , Dupret M.‐A. , Grigahcène A. , Noels A. 
Published: November 2010

AbstractThe question of the existence of the pre‐main sequence (PMS) γ Doradus (γ Dor) pulsators has been raised by observations of young clusters such as NGC 884 hosting γ Dor members. We have explored the properties ofγ Dor‐type pulsations with a grid of PMS models covering the mass range 1.2 < M*/M⊙ < 2.5 and we derive the theoretical instability strip (IS) for the PMS γ Dor pulsators. We explore the possibility of distinguishing between PMS and MS γ Dor by the behaviour of the period spacing of their high order gravity modes (g‐modes) (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
P‐modes in rapidly rotating stars: Looking for regular patterns in synthetic asymptotic spectra
Authors: Lignières F. , Georgeot B. , Ballot J. 
Published: November 2010

AbstractAccording to a recent ray‐based asymptotic theory, the high‐frequency p‐mode spectrum of rapidly rotating stars is a superposition of frequency subsets associated with dynamically independent regions of the ray‐dynamics phase space. At high rotation rates corresponding to typical δ Scuti stars, two frequency subsets are expected to be visible: a regular frequency subset described by a Tassoul‐like formula and an irregular frequency subset with specific statistical properties. In this paper, we investigate whether the regular patterns can be detected in the resulting spectrum. We compute the autocorrelation function of synthetic spectra where the frequencies follow the asymptotic theory, the relative amplitudes are simply given by the modes' disk‐averaging factors, and the frequency resolution is that of a CoRoT long run. Our first results are that (i) the detection of regular patterns strongly depends on the ratio of regular over irregular modes, (ii) low inclination angle configurations are more favorable than near equator‐on configurations, (iii) in the absence of differential rotation, the 2Ω rotational splitting between m = 1 and m = –1 modes is an easy feature to detect (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Complex asteroseismology of the hybrid B‐type pulsatorγPegasi: A test of stellar opacities
Authors: Walczak P. , Daszyńska‐Daszkiewicz J. 
Published: November 2010

AbstractUsing the updated oscillation spectrum ofγPegasi, we construct a set of seismic models which reproduce two pulsational frequencies corresponding to the ℓ = 0, p1and ℓ = 1, g1modes. Then, we single out models which reproduce other well identified modes. Finally, we extend our seismic modelling by a requirement of fitting also values of the complex, nonadiabatic parameterfassociated to each mode frequency. Such complex asteroseismology of the B‐type pulsators provides a unique test of stellar metallicity and opacities. In contrast to our previous studies, results forγPeg indicate that both opacity tables, OPAL and OP, are equally preferred (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Asteroseismology of OB stars with CoRoT
Authors: Degroote P. , Aerts C. , Samadi R. , Miglio A. , Briquet M. , Auvergne M. , Baglin A. , Baudin F. , Catala C. , Michel E. 
Published: November 2010

AbstractThe CoRoT satellite is revolutionizing the photometric study of massive O‐type and B‐type stars. During its long runs, CoRoT observed the entire main sequence B star domain, from typical hotβCep stars, via cooler hybrid p‐ and g‐mode pulsators to the SPB stars near the edge of the instability strip. CoRoT lowers the sensitivity barrier from the typical mmagprecision reached from the ground, to theµmag‐level reached from space. Within the wealth of detected and identified pulsation modes, relations have been found in the form of multiplets, combination of frequencies, and frequency‐ and period spacings. This wealth of observational evidence is finally providing strong constraints to test current models of the internal structure and pulsations of hot stars. Aside from the expected opacity driven modes with infinite lifetime, other unexpected types of variability are detected in massive stars, such as modes of stochastic nature. The simultaneous observation of all these light curve characteristics implies a challenge for both observational asteroseismology and stellar modelling (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the use of rotational splitting asymmetries to probe the internal rotation profile of stars: Application to β Cephei stars
Authors: Suárez J.C. , Andrade L. , Goupil M.J. , Janot‐Pacheco E. 
Published: November 2010

AbstractRotationally‐split modes can provide valuable information about the internal rotation profile of stars. This has been used for years to infer the internal rotation behavior of the Sun. The present work discusses the potential additional information that rotationally splitting asymmetries may provide when studying the internal rotation profile of stars. We present here some preliminary results of a method, currently under development, which intends: 1) to understand the variation of the rotational splitting asymmetries in terms of physical processes acting on the angular momentum distribution in the stellar interior, and 2) how this information can be used to better constrain the internal rotation profile of the stars. The accomplishment of these two objectives should allow us to better use asteroseismology as a test‐bench of the different theories describing the angular momentum distribution and evolution in the stellar interiors (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photometric study of two β Cephei pulsators in ecipsing systems
Authors: Drobek D. , Pigulski A. , Shobbrook R.R. , Narwid A. 
Published: November 2010

AbstractWe present results of a photometric study of the young southern open cluster Stock 14. This cluster is known to contain two eclipsing systems with presumed β Cephei components, HD 101794 and HD 101838. We confirm variability due to pulsations and eclipses in both targets and announce the discovery of other variable stars in the observed field (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Towards ensemble asteroseismology of the young open clusters χ Persei and NGC 6910
Authors: Saesen S. , Pigulski A. , Carrier F. , Michalska G. , Aerts C. , De Ridder J. , Briquet M. , Handler G. , Kołaczkowski Z. , Acke B. , Bauwens E. , Beck P.G. , Blom Y. , Blommaert J. , Broeders E. , Cherix M. , Davignon G. , Debosscher J. , Degroote P. , Decin L. , Dehaes S. , De Meester W. , Deroo P. , Desmet M. , Drummond R. , Eggen J.R. , Fu J. , Gazeas K. , Gelven G.A. , Gielen C. , Huygen R. , Jiang X. , Kalomeni B. , Kim S.‐L. , Kim D.H. , Kopacki G. , Kwon J.‐H. , Ladjal D. , Lee C.‐U. , Lee Y.‐J. , Lefever K. , Leitner A. , Lenz P. , Liakos A. , Lorenz D. , Narwid A. , Niarchos P. , Østensen R. , Poretti E. , Prins S. , Provencal J. , Puga Antolin E. , Puschnig J. , Raskin G. , Reed M.D. , Reyniers M. , Schmidt E. , Schmitzberger L. , Spano M. , Steininger B. , Stęślicki M. , Uytterhoeven K. , Vanautgaerden J. , Vandenbussche B. , Van Helshoecht V. , Vanhollebeke E. , Van Winckel H. , Verhoelst T. , Vučković M. , Waelkens C. , Wolf G.W. , Yakut K. , Zhang C. , Zima W. 
Published: November 2010

AbstractAs a result of the variability survey in χ Persei and NGC 6910, the number of β Cep stars that are members of these two open clusters is increased to twenty stars, nine in NGC 6910 and eleven in χ Persei. We compare pulsational properties, in particular the frequency spectra, of β Cep stars in both clusters and explain the differences in terms of the global parameters of the clusters. We also indicate that the more complicated pattern of the variability among B‐type stars in χ Persei is very likely caused by higher rotational velocities of stars in this cluster. We conclude that the sample of pulsating stars in the two open clusters constitutes a very good starting point for the ensemble asteroseismology of β Cep‐type stars and maybe also for other B‐type pulsators (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Disaggregate safety evaluation for signalized intersections and evaluation tool
Authors: Kweon Young‐Jun 
Published: November 2010

AbstractThis study was to evaluate traffic safety of four‐legged signalized intersections and to develop a spreadsheet tool for identifying high‐risk intersections taking into consideration vehicle movements, left‐turn signal phase types, and times of day. The study used data from Virginia and employed count data models and the empirical Bayes (EB) method for safety evaluation of such intersections. It was found that crash pattern defined by vehicle movements involved in a crash and time of day are important factors for intersection crash analysis. Especially for a safety performance function (SPF), a model specification (Poisson or NB), inclusion of left‐turn signal types, type of traffic flow variables, variable functional forms, and/or magnitudes of coefficients turned out to be different across times of day and crash patterns. The spreadsheet application tool was developed incorporating the developed SPFs and the EB method. As long as Synchro files for signal plans and crash database are maintained, no additional field data collection efforts are required. Adjusting the developed SPFs and the spreadsheet for recent traffic and safety conditions can be done by applying the calibration methods employed in the SafetyAnalyst software and the Highway Safety Manual. Implementing the developed tool equipped with streamlining data entry would greatly improve accuracy and efficiency of safety evaluation of four‐legged signalized intersections in localities and highway agencies that cannot operate the SafetyAnalyst. Copyright © 2010 John Wiley & Sons, Ltd.
A decision support system for total airport operations management and planning
Authors: Zografos Konstantinos G. , Madas Michael A. , Salouras Yiannis 
Published: November 2010

SUMMARYThe airport planning and decision making process exhibits various trade‐offs and complications due to the large number of stakeholders having different, and sometimes conflicting, objectives regarding the assessment of airport performance. As a result, the airport performance assessment necessitates the use of advanced modelling capabilities and decision support systems or tools in order to capture the multifaceted aspects, interests and measures of airport performance like capacity, delays, safety, security, noise and cost‐effectiveness. Presently, airport decision makers lack decision support tools able to provide an integrated view of total airport (both airside and landside) operations and analyse at a reasonable effort and decision‐oriented manner the various trade‐offs involved among different airport performance measures. The objective of this paper is twofold: (i) to describe the decision‐oriented modelling framework and development process of a decision support system for total airport operations management and planning, and (ii) to demonstrate the decision support capabilities and basic modelling functionalities of the proposed system. Copyright © 2010 John Wiley & Sons, Ltd.
Life cycle assessment of selected future energy crops for Europe
Authors: Rettenmaier Nils , Köppen Susanne , Gärtner Sven O. , Reinhardt Guido A. 
Published: November 2010

AbstractLife cycle assessment (LCA) methodology is increasingly used to determine the potential environmental impacts of biofuels and bioenergy. This paper presents the outcomes of screening LCAs of 13 future energy crops for Europe summarizing the results of the EC‐funded project4F CROPS – Future Crops for Food, Feed, Fiber and Fuel. For analysis, these dedicated energy crops – representing seven environmental zones in Europe – are combined with a multitude of processing and utilization options, resulting in 120 different biofuel and bioenergy chains. Compared to fossil fuels and energy carriers, all biofuel and bioenergy chains show environmental advantages in terms of life‐cycle energy use and greenhouse gas (GHG) emissions but mostly disadvantages regarding other environmental impact categories. Quantitative results vary widely across environmental zones, depending on crop species, agricultural inputs, and yield. Moreover, coproduct accounting and coproduct utilization, as well as the agricultural and fossil reference system play an important role. In view of environmental advantages and disadvantages, subjective trade‐offs are required between the environmental impact categories. If saving GHG emissions is given the highest environmental priority, combined heat and power generation from herbaceous lignocellulosic crops is the most efficient option in terms of land use, provided that the biomass is cultivated on surplus agricultural land, thus avoiding indirect land‐use change. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd
Economic viability of energy crops in the EU: the farmer's point of view
Authors: Soldatos Peter , Lychnaras Vassilis , Panoutsou Calliope , Cosentino Salvatore L. 
Published: November 2010

AbstractNowadays, the cultivation of energy crops is, in most cases, directly or indirectly subsidized at EU and global levels. However, their financial viability, i.e. sustainable profitability in the absence of subsidies, is not too remote any more given the increasing cost of fossil fuels, pressing environmental concerns, and the rapid technological progress in the renewable energies field.This analysis presents a number of case studies examining the viability of the most promising oil and sugar crops for the production of first‐generation biofuels. The presented outputs of this work indicate that today, the viability of energy crops, such as rapeseed (Brassica napus), Brassica carinata, sunflower and sweet sorghum, can be attained under favorable conditions. Detailed cost analysis of these crops in various European regions leads to the estimation of profitability and illustrates their financial profile. Comparative analyses are made with the most widespread conventional food crops, such as wheat and maize.The results of the study have shown that first‐generation oil producing crops in Europe are worth cultivating under current support regimes and under favorable market conditions. In view of the prevailing instability in the price of crops, the farmer has to make decisions on a rather short‐term basis. Sweet sorghum in southern Europe appears to be a very promising proposition for the production of bioethanol, as it appears much more efficient than cereals and sugarbeets, which are used today in the bioethanol industry. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd
Direct and indirect land‐use competition issues for energy crops and their sustainable production – an overview
Authors: Fritsche Uwe R. , Sims Ralph E. H. , Monti Andrea 
Published: November 2010

AbstractBiofuel production from energy crops is land‐use intensive. Land‐use change (LUC) associated with bioenergy cropping impacts on the greenhouse gas (GHG) balance, both directly and indirectly. Land‐use conversion can also impact on biodiversity.The current state of quantifying GHG emissions relating to direct and indirect land‐use change (iLUC) from biomass produced for liquid biofuels or bioenergy is reviewed. Several options for reducing iLUC are discussed, and recommendations made for considering LUC in bioenergy and biofuel policies.Land used for energy cropping is subject to competing demands for conventional agriculture and forest production, as well as for nature protection and conservation. Biomass to be used for bioenergy and biofuels should therefore be produced primarily from excess farm and forest residues or from land not required for food and fiber production. The overall efficiency of biomass production, conversion, and use should be increased where possible in order to further reduce land competition and the related direct and iLUC risks.This review of several varying approaches to iLUC substantiates that, in principle, GHG emissions can be quantified and reductions implemented by appropriate policies. Such approaches can (and should) be refined and substantiated using better data on direct LUC trends from global monitoring, and be further improved by adding more accurate estimates of future trade patterns where appropriate.This brief discussion of current policies and options to reduce iLUC has identified a variety of approaches and options so that a quantified iLUC factor could be translated into practical regulations – both mandatory and voluntary – with few restrictions.Depending on the future development of energy cropping systems and yield improvements, sustainable bioenergy production could make a significant contribution to the future global energy demand. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd
Potential land availability for energy crops production in Europe
Authors: Krasuska Ewa , Cadórniga Carlos , Tenorio José L , Testa Giorgio , Scordia Danilo 
Published: November 2010

AbstractThe European Union (EU) has set quite an ambitious goal for biofuels contribution to the makeup of the renewable energy mix in the next decades. While substantial efforts have been made to develop the technologies for the transformation of biomass into biofuels, it is still uncertain to what extent the EU will be able to generate the biomass needed to meet its targets without compromising domestic food security. Using a bottom‐up approach, this review addresses one of the key elements: the potential availability of land for non‐food crops in the EU. The assessment is based on a land allocation model, which calculates surplus land that would be available for non‐food crops after satisfying food and feed demands. Projections of future agriculture productivity and changes in population are the most important parameters of the modeling applied for two future scenarios established for the years 2020 and 2030. The total area potentially available for non‐food crops in the EU‐27 (excluding Cyprus and Malta) is estimated to be 13.2 million ha in the current situation, with fallow land the largest contributor. In scenarios 2020 and 2030, additional land would be released from food and fodder crops, resulting in total land potential of 20.5 million ha in 2020 and 26.2 million ha in 2030. Results presented on a regional basis indicate potential locations for biomass transformation plants in terms of feedstock production. A set of non‐food crops can be recommended for the diverse climate and agronomic conditions of the entire EU area. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd