bluuebunny/crossref_metadata_2025 huggingface dataset:
The most massive pulsating white dwarf stars
Authors: Castanheira Barbara G. , Kepler S. O.
Published: February 2014

Massive pulsating white dwarf stars are extremely rare, because of their small size and because they are the final product of high-mass stars, which are less common. Because of their intrinsic smaller size, they are fainter than the normal size white dwarf stars. The motivation to look for this type of stars is to be able to study in detail their internal structure and also derive generic properties for the sub-class of variables, the massive ZZ Ceti stars. Our goal is to investigate whether the internal structures of these stars differ from the lower-mass ones, which in turn could have been resultant from the previous evolutionary stages.

In this paper, we present the ensemble seismological analysis of the known massive pulsating white dwarf stars. Some of these pulsating stars might have substantial crystallized cores, which would allow us to probe solid physics in extreme conditions.
Origin and pulsation of hot subdwarfs
Authors: Randall S. K. , Fontaine G. , Charpinet S. , Van Grootel V. , Brassard P.
Published: February 2014

We briefly introduce hot subdwarfs and their evolutionary status before discussing the different types of known pulsators in more detail. Currently, at least six apparently distinct types of variable are known among hot subdwarfs, encompassing p- as well as g-mode pulsators and objects in the Galactic field as well as in globular clusters. Most of the oscillations detected can be explained in terms of an iron opacity mechanism, and quantitative asteroseismology has been very successful for some of the pulsators. In addition to helping constrain possible evolutionary scenarios, studies focussing on stellar pulsations have also been used to infer planets and characterize the rotation of the host star.
Reaching the 1% accuracy level on stellar mass and radius determinations from asteroseismology
Authors: Van Grootel V. , Charpinet S. , Fontaine G. , Brassard P. , Green E. M.
Published: February 2014

Asteroseismic modeling of subdwarf B (sdB) stars provides measurements of their fundamental parameters with a very good precision; in particular, the masses and radii determined from asteroseismology are found to typically reach a precision of 1% containing various uncertainties associated with their inner structure and the underlying microphysics (composition and transition zones profiles, nuclear reaction rates, etc.). Therefore, the question of the accuracy of the stellar parameters derived by asteroseismology is legitimate. We present here the seismic modeling of the pulsating sdB star in the eclipsing binary PG 1336–018, for which the mass and the radius are independently and precisely known from the modeling of the reflection/irradiation effect and the eclipses observed in the light curve. This allows us to quantitatively evaluate the reliability of the seismic method and test the impact of uncertainties in our stellar models on the derived parameters. We conclude that the sdB star parameters inferred from asteroseismology are precise, accurate, and robust against model uncertainties.
Being rich helps – the case of the sdBV KIC 10670103
Authors: Krzesinski Jurek , Bachulski Szymon
Published: February 2014

We present a study of KIC 10670103, a pulsating hot subdwarf in the Kepler field. By means of Fourier analysis, we investigate periodic signals associated with pulsations. Using asymptotic relationships and rotational multiplets we identify degrees of modes. The Fourier spectrum appears to be rich in l=1 and l=2 multiplets allowing derivation of a ~90-day rotation period of the star from rotational splittings. Comparing the identified gravity-mode period spacing pattern with theoretical models we show that KIC 10670103 has to be a thick-envelope sdBV.
Pulsations in hot supergiants
Authors: Godart Melanie , Grotsch-Noels Arlette , Dupret Marc-Antoine
Published: February 2014

Massive stars are the cosmic engines that shape and drive our Universe. Many issues such as their formation, their stability and the mass loss effects, are far from being completely understood. Recent ground-based and space observations have shown pulsations in massive MS and post-MS stars, such as acoustic and gravity modes excited by the κ-mechanism and even solar-like oscillations. Theoretical studies emphasized the presence of strange modes in massive models, and recent theoretical analyses have shown that hot supergiants can pulsate in oscillatory convective modes. We review the instability domains of massive stars as well as their excitation mechanisms and present the latest results.
Stochastically excited oscillations in the upper main sequence
Authors: Antoci Victoria
Published: February 2014

Convective envelopes in stars on the main sequence are usually connected only with stars of spectral types F5 or later. However, observations as well as theory indicate that the convective outer layers in hotter stars, despite being shallow, are still effective and turbulent enough to stochastically excite oscillations. Because of the low amplitudes, exploring stochastically excited pulsations became possible only with space missions such as Kepler and CoRoT. Here I review the recent results and discuss among others, pulsators such as δ Scuti, γ Doradus, roAp, β Cephei, Slowly Pulsating B and Be stars, all in the context of solar-like oscillations.
Energy of solar-like oscillations in red giants
Authors: Grosjean Mathieu , Dupret Marc-Antoine , Belkacem Kevin , Montalbán Josefina , Samadi Reza
Published: February 2014

CoRoT and Kepler observations of red giants reveal a large variety of spectra of nonradial solar-like oscillations. So far, we understood pretty well the link between the global properties of the star (radius, mass, evolutionary state) and the properties of the oscillation spectrum (Δν, νmax, period spacing). We are interested here in the theoretical predictions of two other components of a power spectrum, the mode linewidths and heights. The study of the energy of the oscillations is of great importance to predict the peak parameters in the power spectrum. We will discuss circumstances under which mixed modes are detectable for red-giant stellar models from 1 to 2 M⊙, with emphasis on the effect of the evolutionary status of the star along the red-giant branch on theoretical power spectra.
3D simulations of internal gravity waves in solar-like stars
Authors: Alvan Lucie , Brun Allan Sacha , Mathis Stéphane
Published: February 2014

We perform numerical simulations of the whole Sun using the 3D anelastic spherical harmonic (ASH) code. In such models, the radiative and convective zones are non-linearly coupled and in the radiative interior a wave-like pattern is observed. For the first time, we are thus able to model in 3D the excitation and propagation of internal gravity waves (IGWs) in a solar-like star's radiative zone. We compare the properties of our waves to theoretical predictions and results of oscillation calculations. The obtained good agreement allows us to validate the consistency of our approach and to study the characteristics of IGWs. We find that a wave's spectrum is excited up to radial order n=58. This spectrum evolves with depth and time; we show that the lifetime of the highest-frequency modes must be greater than 550 days. We also test the sensitivity of waves to rotation and are able to retrieve the rotation rate to within 5% error by measuring the frequency splitting.
Corotation resonances for gravity waves and their impact on angular momentum transport in stellar interiors
Authors: Alvan Lucie , Mathis Stéphane , Decressin Thibaut
Published: February 2014

Gravity waves, which propagate in radiation zones, can extract or deposit angular momentum by radiative and viscous damping. Another process, poorly explored in stellar physics, concerns their direct interaction with the differential rotation and the related turbulence. In this work, we thus study their corotation resonances, also called critical layers, that occur where the Doppler-shifted frequency of the wave approaches zero. First, we study the adiabatic and non-adiabatic propagation of gravity waves near critical layers. Next, we derive the induced transport of angular momentum. Finally, we use the dynamical stellar evolution code STAREVOL to apply the results to the case of a solar-like star. The results depend on the value of the Richardson number at the critical layer. In the first stable case, the wave is damped. In the other unstable and turbulent case, the wave can be reflected and transmitted by the critical layer with a coefficient larger than one: the critical layer acts as a secondary source of excitation for gravity waves. These new results can have a strong impact on our understanding of angular momentum transport processes in stellar interiors along stellar evolution where strong gradients of angular velocity can develop.
Precise and accurate interpolated stellar oscillation frequencies on the main sequence
Authors: Ball Warrick H. , Schou Jesper , Gizon Laurent , Marques João P. C.
Published: February 2014

High-quality data from space-based observatories present an opportunity to fit stellar models to observations of individually-identified oscillation frequencies, not just the large and small frequency separations. But such fits require the evaluation of a large number of accurate stellar models, which remains expensive. Here, we show that global-mode oscillation frequencies interpolated in a grid of stellar models are precise and accurate, at least in the neighbourhood of a solar model.
Variability of M giant stars based on Kepler photometry: general characteristics
Authors: Bányai E. , Kiss L. L.
Published: February 2014

Our study based on the continuous, high-precision observations covering more than three years provided by the Kepler mission reveals a new systematic effect in the data, a possible transition region between solar-like and Mira-like oscillations, and gives an overview of M giant variability on a wide range of time-scales (hours to years).
Helio- and asteroseismology shedding light on “new physics”
Authors: Biesiada Marek
Published: February 2014

Linkages between astronomy and physics have always been intimately close and mutually stimulating. Most often it was physics that served astronomy with its explanatory power. Today, however, we are increasingly witnessing the reverse: astrophysical considerations are being used to constrain new physics and moreover they are more efficient than laboratory experiments. This contribution reviews the ways helio- and white dwarf asteroseismology – branches in which Wojtek Dziembowski played a prominent role – are used for this purpose.
The IPoP method to measure Cepheid distances
Authors: Breitfelder J. , Mérand A. , Kervella P. , Gallenne A.
Published: February 2014

Cepheids are one of the most famous standard candles used to calibrate the Galactic distance scale. However, it is fundamental to develop and test independent tools to measure their distances, in order to reach a better calibration of their period-luminosity (P-L) relationship. We present here the first results obtained with the Integrated Parallax of Pulsation (IPoP) method, an extension of the classical Baade-Wesselink method that derives the distance by making a global modelisation of all the available data. With this method we aim to reach a 2% accuracy on distance measurements.

Cepheid masses are also an essential key for our comprehension of those objects. We briefly present an original approach to derive observational constraint on Cepheid masses. Unfortunately, it does not lead to promising results.
Multicolour photometry of pulsating stars in the Galactic Bulge fields
Authors: Bruś Przemysław , Kołaczkowski Zbigniew
Published: February 2014

We present a study of photometric properties of very crowded stellar fields toward the Galactic Bulge. We performed a search for pulsating stars among thousands of variable stars from the OGLE-II survey supplementing the variability study with photometric measurements in four Johnson-Cousins UBVIC passbands. Using these data, we analysed the properties of objects located at different distances and, whenever possible, classified them.
What asteroseismology can teach us about low-mass core helium burning models
Authors: Constantino Thomas N. , Campbell Simon W. , Lattanzio John C.
Published: February 2014

Standard models of low-mass core helium burning stars typically give an asymptotic l=1 g-mode period spacing well below that inferred from observed mixed modes. We find that most physical uncertainties, such as mixing beyond the fully convective core, are not significant enough to be responsible for such a discrepancy. The solution to the problem may lie in a deviation of structure away from its canonical form, such as a more massive H-exhausted core, which we briefly explore here.
Asteroseismology with the new opacity bump at log T ≈ 5.06
Authors: Cugier H.
Published: February 2014

Although the κ mechanism of pulsations is known for early-type stars, opacities and the equation of state are still uncertain. Stellar models calculated for the OP data implemented with the new Kurucz opacities at log T < 5.2 were investigated for different chemical compositions of elements. The additional metallic opacity bump at log T ≈ 5.06 that occurs in the Kurucz data changes markedly the oscillation spectra of unstable modes. Basic properties of the new opacity bump and examples of seismic models are shown. B-type stars observed in the Galaxy, LMC and SMC were considered. The problem was studied using Dziembowski's computing codes for linear, non-adiabatic and non-radial oscillations.
Spectroscopic and photometric study of two B-type pulsators in eclipsing systems
Authors: Drobek Dominik , Pigulski Andrzej
Published: February 2014

Pulsating stars in eclipsing binary systems play an important role in asteroseismology. The combination of their spectroscopic and photometric orbital solutions can be used to determine, or at least to constrain, the masses and radii of components. To successfully perform any seismic modelling of a star, one has to identify at least some of the detected modes, which requires precise time-series photometric and spectroscopic observations. This work presents a progress report on the analysis of two β Cephei-type stars in eclipsing binaries: HD 101794 (V916 Cen) and HD 167003 (V4386 Sgr).
An interferometric view on binarity and circumstellar envelopes of Cepheids
Authors: Gallenne A. , Kervella P. , Mérand A. , Monnier J. D. , Breitfleder J. , Pietrzyński G. , Gieren W.
Published: February 2014

Optical interferometry is the only technique giving access to milli-arcsecond (mas) resolution at infrared wavelengths. For Cepheids, this is a powerful and unique tool to detect the orbiting companions and the circumstellar envelopes (CSE). CSEs are interesting because they might be used to trace the Cepheid evolution history, and more particularly they could impact the distance scale. Cepheids belonging to binary systems offer an unique opportunity to make progress in resolving the Cepheid mass discrepancy. The combination of spectroscopic and interferometric measurements will allow us to derive the orbital elements, distances, and dynamical masses. Here we focus on recent results using 2- to 6-telescopes beam combiners for the Cepheids X Sgr, T Mon and V1334 Cyg.
Searching for pulsations in Kepler eclipsing binary stars
Authors: Gaulme Patrick , Guzik Joyce A.
Published: February 2014

Eclipsing binaries can in principle provide additional constraints to facilitate asteroseismology of one or more pulsating components. We have identified 94 possible eclipsing binary systems in a sample of over 1800 stars observed in long cadence as part of the Kepler Guest Observer Program to search for γ Doradus and δ Scuti star candidates. We show the results of a procedure to fold the light curve to identify the potential binary period, subtract a fit to the binary light curve, and perform a Fourier analysis on the residuals to search for pulsation frequencies that may arise in one or both of the stellar components. From this sample, we have found a large variety of light curve types; about a dozen stars show frequencies consistent with δ Sct or γ Dor pulsations, or light curve features possibly produced by stellar activity (rotating spots). For several stars, the folded candidate ‘binary’ light curve resembles more closely that of an RR Lyr, Cepheid, or high-amplitude δ Sct star. We show highlights of our results and discuss the potential for asteroseismology of the most interesting objects.
LIMBO: A time-series Lucky Imaging survey of variability in Galactic globular clusters
Authors: Kains N. , Bramich D. M. , Jaimes R. Figuera , Skottfelt J.
Published: February 2014

We present a large observing project monitoring globular clusters (GC) over long time baselines, which will lead to a complete census of variable stars in those clusters down to several magnitudes below the horizontal branch (HB). The use of Lucky Imaging (LI) will allow us to obtain high-precision photometry for even faint objects, and long-term monitoring will also mean that observations are sensitive to detecting other slow transient phenomena, such as gravitational microlensing, the primary aim of this project.
Global Astrophysical Telescope System — telescope No. 2
Authors: Kamiński Krzysztof , Baranowski Roman , Fagas Monika , Borczyk Wojciech , Dimitrov Wojciech , Polińska Magdalena
Published: February 2014

We present the new, second spectroscopic telescope of Poznań Astronomical Observatory. The telescope allows automatic simultaneous spectroscopic and photometric observations and is scheduled to begin operation from Arizona in autumn 2013. Together with the telescope located in Borowiec, Poland, it will constitute a perfect instrument for nearly continuous spectroscopic observations of variable stars. With both instruments operational, the Global Astrophysical Telescope System will be established.
The Large Magellanic Cloud Cepheids: effects of helium content variations
Authors: Marconi Marcella , Carini Roberta , Brocato Enzo , Raimondo Gabriella
Published: February 2014

An extended set of evolutionary and pulsational models has been computed for two chemical compositions representative of classical Cepheids in the Large Magellanic Cloud. The comparison between the standard and He enhanced theoretical predictions is analysed and the implications for interpreting current observations and for defining the Cepheid based distance scale are discussed.
Variable stars in the young open cluster NGC 2244
Authors: Michalska Gabriela
Published: February 2014

We present results of a search for variable stars in the young open cluster NGC 2244. As a result we have found many eclipsing systems and pulsating stars, some of which are multiperiodic. Here we show only a few examples.
Spectroscopic survey of Kepler stars: high-resolution observations of A- and F-type stars
Authors: Niemczura E. , Smalley B. , Murphy S. , Catanzaro G. , Uytterhoeven K. , Drobek D. , Briquet M. , De Cat P. , Marcos-Arenal P. , Pápics P. I. , Gameiro J. F. S.
Published: February 2014

Basic stellar parameters such as effective temperature, surface gravity, chemical composition, and projected rotational velocity, are important to classify stars and are crucial for successful asteroseismic modelling. However, the Kepler space data do not provide such information. Therefore, ground-based spectral and multi-colour observations of Kepler asteroseismic targets are necessary to complement the space data. For this purpose, in coordination with the KASC ground-based observational Working Groups, high-resolution spectroscopic data for more than 500 B, A, F and G-type stars were collected.
On the interchange of alternating-amplitude pulsation cycles
Authors: Plachy E. , Molnár L. , Kolláth Z. , Benkő J. M. , Kolenberg K.
Published: February 2014

We characterized the time intervals between the interchanges of the alternating high- and low-amplitude extrema of three RV Tauri and three RR Lyrae stars.
Order and chaos in hydrodynamic BL Her models
Authors: Smolec Radosław , Moskalik Paweł
Published: February 2014

Many dynamical systems of different complexity, e.g. 1D logistic map, the Lorentz equations, or real phenomena, like turbulent convection, show chaotic behaviour. Despite huge differences, the dynamical scenarios for these systems are strikingly similar: chaotic bands are born through the series of period doubling bifurcations and merge through interior crises. Within chaotic bands periodic windows are born through the tangent bifurcations, preceded by the intermittent behaviour. We demonstrate such behaviour in models of pulsating stars.
Analysis of strange-mode instability with time-dependent convection in hot massive stars
Authors: Sonoi Takafumi , Shibahashi Hiromoto
Published: February 2014

We carry out nonadiabatic analysis of strange-modes in hot massive stars with time-dependent convection (TDC) for the first time. Although convective luminosity in envelopes of hot massive stars is not as dominative as in stars near the red edge of the classical Cepheid instability strip in the Hertzsprung-Russell (H-R) diagram, we have found that the strange-mode instability can be affected by the treatment of convection. However, existence of the instability around and over the Humphreys-Davidson (H-D) limit is independent of the treatment. This implies that the strange-mode instability could be responsible for the lack of observed stars over the H-D limit regardless of uncertainties on convection theories.
The fast rotating δ Scuti pulsator V376 Per: Frequency analysis and mode identification
Authors: Themessl Nathalie , Fritz Veronique , Breger Michel , Karrer Sabine , Castanheira Barbara G.
Published: February 2014

Our simultaneous analysis of ground-based photometric and high-resolution spectroscopic data of the δ Scuti star V376 Per revealed eight individual frequencies from 82 nights of two-color photometry and six frequencies from the line-profile variations using 769 stellar spectra. Additionally, we identified the corresponding pulsation modes and derived reliable estimates of the line profile and pulsation mode parameters.
Pulsations in the late-type B supergiant star HD 202850
Authors: Tomić Sanja , Kraus Michaela , Oksala Mary
Published: February 2014

HD 202850 is a late B-type supergiant. It is known that photospheric lines of such stars vary. Due to macroturbulence the lines are much wider than expected. Macroturbulence has been linked to stellar pulsations. It has been reported that there are several B supergiants that undergo pulsations. In our previous work, we detected a pulsational period of 1.59 hours in this object from data taken with the Ondřejov 2-m telescope. We continued to investigate this object and we took several time series with the DAO 1.2-m telescope. Our new data suggest that there may be some additional pulsational periods in this star. We present our new results in this poster.
Antarctica photometric survey using PDM13
Authors: Zalian Cyrus , Chadid Merieme
Published: February 2014

PDM13 is a new graphic interface program dedicated to frequency domain analysis based on the Phase Dispersion Minimization technique (PDM, Stellingwerf 2012). In this paper, we will present the different algorithms running in PDM13, including the Auto-Segmentation, the Gauss-Newton and the PDM algorithms. More details on this triptych are available in our recent paper (Zalian et al., submitted). Their aim is to offer a simple and powerful way to extract frequency. Amongst the numerous improvements offered by the program, we will particularly focus on the reduction of aliases and the ability to look directly for multiple-period phenomena and the Blazhko effect. After that, we will show the first results from PDM13 using the Antarctica photometric survey.
Molecular phylogeny of Myriapoda provides insights into evolutionary patterns of the mode in post-embryonic development
Authors: Miyazawa Hideyuki , Ueda Chiaki , Yahata Kensuke , Su Zhi-Hui
Published: February 2014

Myriapoda, a subphylum of Arthropoda, comprises four classes, Chilopoda, Diplopoda, Pauropoda and Symphyla. While recent molecular evidence has shown that Myriapoda is monophyletic, the internal phylogeny, which is pivotal for understanding the evolutionary history of myriapods, remains unresolved. Here we report the results of phylogenetic analyses and estimations of divergence time and ancestral state of myriapods. Phylogenetic analyses were performed based on three nuclear protein-coding genes determined from 19 myriapods representing the four classes (17 orders) and 11 outgroup species. The results revealed that Symphyla whose phylogenetic position has long been debated is the sister lineage to all other myriapods and that the interordinal relationships within classes were consistent with traditional classifications. Ancestral state estimation based on the tree topology suggests that myriapods evolved from an ancestral state that was characterized by a hemianamorphic mode of post-embryonic development and had a relatively low number of body segments and legs.
Development of the crosslinking reactions to RNA triggered by oxidation
Authors: Kusano Shuhei , Haruyama Takuya , Ishiyama Shogo , Hagihara Shinya , Nagatsugi Fumi
Published: February 2014

In this paper, we have reported a novel oxidation triggered crosslinking nucleobase ATVP (1) and demonstrated that the oxidized form ASVP (2) showed a very fast and selective crosslinking reaction to cytosine in RNA.
Photocatalytic conversion of carbon dioxide into methanol in reverse fuel cells with tungsten oxide and layered double hydroxide photocatalysts for solar fuel generation
Authors: Morikawa Motoharu , Ogura Yuta , Ahmed Naveed , Kawamura Shogo , Mikami Gaku , Okamoto Seiji , Izumi Yasuo
Published: February 2014

Photofuel cells comprising WO3 and layered double hydroxide converted gaseous CO2 into methanol whereas hydrogen was formed in the aqueous phase.
VersatileC3-symmetric scaffolds and their use for covalent stabilization of the foldon trimer
Authors: Berthelmann Arne , Lach Johannes , Gräwert Melissa A. , Groll Michael , Eichler Jutta
Published: February 2014

Attachment of foldon monomers to a trimesic acid scaffold enhances thermal stability of the trimer, while maintaining the correct fold.
Plasma and brain pharmacokinetics of previously unexplored lithium salts
Authors: Smith Adam J. , Kim Seol-Hee , Tan Jun , Sneed Kevin B. , Sanberg Paul R. , Borlongan Cesar V. , Shytle R. Douglas
Published: February 2014

Despite its narrow therapeutic window, lithium is still regarded as the gold standard comparator and benchmark treatment for mania.
Diastereoselection during 1,2-addition of 3-bromomethyl-5H-furan-2-one to α-chiral aldehydes mediated by indium in aqueous and organic solvent systems: direct route to obtain optically active α-methylene-γ-butyrolactones
Authors: Zhang Fuhai , Liu Yang , Xie Longguan , Xu Xiaohua
Published: February 2014

High chelation control or Felkin–Ahn selective allylic addition of2to α-hydroxyaldehydes or α-rigid aldehydes mediated by indium.
Preconcentration of Ag and Pd ions using graphite oxide and 2,6-diaminopyridyne from water, anode slime and catalytic converter samples
Authors: Yıldırım Gülşen , Tokalıoğlu Şerife , Şahan Halil , Patat Şaban
Published: February 2014

In this work, graphite oxide was used for the first time as an effective adsorbent for the separation/preconcentration of Ag and Pd ions in various samples prior to flame atomic absorption detection.
Th(VO3)2(SeO3) and Ln(VO3)2(IO3) (Ln = Ce, Pr, Nd, Sm, and Eu): unusual cases of aliovalent substitution
Authors: Eaton Teresa , Lin Jian , Cross Justin N. , Stritzinger Jared T. , Albrecht-Schmitt Thomas E.
Published: February 2014

Six isotypic compounds with rather extreme examples of aliovalent substitution (ThIVvs. LnIII; SeO32−vs. IO3−) have been synthesized.
Silver-catalyzed dynamic systemic resolution of α-iminonitriles in a 1,3-dipolar cycloaddition process
Authors: Hu Lei , Ramström Olof
Published: February 2014

A silver-catalyzed dynamic azomethine ylide system was kinetically resolved in a tandem cycloaddition process, yielding an exclusive pyrrolidine product.
Non-symmetric 9,10-diphenylanthracene-based deep-blue emitters with enhanced charge transport properties
Authors: Serevičius Tomas , Komskis Regimantas , Adomėnas Povilas , Adomėnienė Ona , Jankauskas Vygintas , Gruodis Alytis , Kazlauskas Karolis , Juršėnas Saulius
Published: February 2014

Realization of 9,10-diphenylanthracene based deep-blue emitters exhibiting high fluorescence efficiency, demonstrating good film forming properties and high carrier drift mobilities is presented.
Australian carbon tetrachloride emissions in a global context
Authors: Fraser Paul J. , Dunse Bronwyn L. , Manning Alistair J. , Walsh Sean , Wang R. Hsiang J. , Krummel Paul B. , Steele L. Paul , Porter Laurie W. , Allison Colin , O'Doherty Simon , Simmonds Peter G. , Mühle Jens , Weiss Ray F. , Prinn Ronald G.
Published: February 2014

Environmental context Carbon tetrachloride in the background atmosphere is a significant environmental concern, responsible for ~10% of observed stratospheric ozone depletion. Atmospheric concentrations of CCl4 are higher than expected from currently identified emission sources: largely residual emissions from production, transport and use. Additional sources are required to balance the expected atmospheric destruction of CCl4 and may contribute to a slower-than-expected recovery of the Antarctic ozone ‘hole’. Abstract Global (1978–2012) and Australian (1996–2011) carbon tetrachloride emissions are estimated from atmospheric observations of CCl4 using data from the Advanced Global Atmospheric Gases Experiment (AGAGE) global network, in particular from Cape Grim, Tasmania. Global and Australian emissions are in decline in response to Montreal Protocol restrictions on CCl4 production and consumption for dispersive uses in the developed and developing world. However, atmospheric data-derived emissions are significantly larger than ‘bottom-up’ estimates from direct and indirect CCl4 production, CCl4 transportation and use. Australian CCl4 emissions are not a result of these sources, and the identification of the origin of Australian emissions may provide a clue to the origin of some of these ‘missing’ global sources.
Diversity and species identity effects on fine root productivity and turnover in a species-rich temperate broad-leaved forest
Authors: Jacob Andreas , Hertel Dietrich , Leuschner Christoph
Published: February 2014

We investigated the evidence of belowground overyielding in a species-rich temperate broad-leaved forest with an ingrowth core study in 100 plots containing five common tree species (beech, lime, maple, hornbeam, ash) in mono-specific and 2-species or 3-species combinations. This design allowed separating diversity and species identity effects on root dynamics in a mature forest with long continuity. Fine root productivity was not significantly different between mono-specific and 2- or 3-species plots, whereas fine root turnover was significantly higher in the mixed than the mono-specific plots. Species identity effects on root turnover and root productivity were important. Ash achieved in the mixtures the highest fine root productivity and root turnover of all species; it is an apparent key species in this forest. Evidence in support of a diversity effect on fine root productivity and turnover was weak, however.
Continuous monitoring of feeding by koalas highlights diurnal differences in tree preferences
Authors: Marsh Karen J. , Moore Ben D. , Wallis Ian R. , Foley William J.
Published: February 2014

Context
It is difficult to measure feeding rates for most wild nocturnal mammalian herbivores. Thus, although koalas are a popular species to study, we have a poor understanding of their activity patterns and feeding ecology. Researchers often assume that the trees that koalas occupy during the day indicate feeding preferences, but they may better reflect preferred resting sites.

Aims
We recorded the activities of koalas, with an emphasis on their feeding, particularly when they fed, the trees that they fed from, the number of meals they consumed and the variability in these measurements.

Methods
We continuously monitored eight koalas by audio- and radio-telemetry for 14 consecutive 24-h periods each. We followed two koalas at a time and recorded the trees they visited, when, where and how long they fed, and the size and nutritional composition of the trees in the landscape.

Key results
Individual koalas varied in how many trees they visited, how many meals they ate and how long they spent feeding during each 24-h period. They preferred Eucalyptus globulus trees during the day, but fed mainly at night, with a preference for E. viminalis. The trees that koalas visited during the day were larger than those that they visited at night.

Conclusions
The trees that koalas occupied during the day were poor indicators of their diet preferences, whereas the daily feeding activities of individual koalas varied widely.

Implications
Predicting a koala’s diet from the trees it occupies during the day is fraught with error. Although the trees that koalas rest in are important in the species ecology for reasons other than feeding, we should refrain from using them to predict an animal’s diet. Because feeding activity is difficult to measure, it is probably best done indirectly by analysing leaf-cuticle fragments or waxes in faeces. The substantial day-to-day variation in koala activities also indicates that behavioural and physiological studies of koalas require long monitoring periods – a week or longer.
Heart rate response and fitness effects of various types of physical education for 8‐ to 9‐year‐old schoolchildren
Authors: Bendiksen Mads , Williams Craig A. , Hornstrup Therese , Clausen Helle , Kloppenborg Jesper , Shumikhin Dmitriy , Brito João , Horton Joshua , Barene Svein , Jackman Sarah R. , Krustrup Peter
Published: February 2014

The present study investigated the heart rate (HR) response to various types of physical education (PE) activities for 8‐ to 9‐year‐olds (five school classes, n = 93) and the fitness effects of a short‐term PE training programme (three of the five classes, n = 59) with high compared to low‐to‐moderate aerobic intensity. HR was recorded during small‐sided indoor soccer (SO), basketball (BB), unihockey (UH), circuit training (CT), walking (W) and Nintendo Wii Boxing (NWB) and Nintendo Wii Tennis (NWT). Maximal HR (HRmax) and physical fitness was determined by the Yo‐Yo Intermittent Recovery Level 1 Children's test (YYIR1C) test. Following cluster randomisation, three classes were tested before and after 6 wks with 2 × 30 min/wk SO and UH lessons [high‐intensity (HI), 2 classes, n = 39] or low‐to‐moderate intensity PE lessons (CON, 1 class, n = 20). Average HR in SO (76 ± 1% HRmax), BA (77 ± 1% HRmax) and UH (74 ± 1% HRmax) was higher (P < 0.05) than in CT (62 ± 1% HRmax), W (57 ± 1% HRmax), NWB (65 ± 2% HRmax) and NWT (57 ± 1% HRmax). Time with HR > 80% and 90% HRmax, respectively, was higher (P < 0.05) in SO (42 ± 4 and 12 ± 2%), BB (41 ± 5 and 13 ± 3%) and UH (34 ± 3 and 9 ± 2%) than in CT, W and NW (0–5%), with time >80% HRmax being higher (P < 0.05) in SO than UH. After 6 wk, YYIR1C performance was increased (P < 0.05) by 22% in HI (673 ± 57 to 821 ± 71 m), but unaltered in CON (674 ± 88 to 568 ± 81 m). HR 2 min into YYIR1C was lowered (P < 0.05) in HI after 6 wks (92.4 ± 0.8 to 89.1 ± 0.9% HRmax), but not in CON. In conclusion, ball games elicited high aerobic loading for young schoolchildren and a short‐term, low‐volume ball game PE‐intervention improved physical fitness. Traditional PE sessions had no effects on intermittent exercise performance.
An APN model for Arrhythmic beat classification
Authors: Chiang Hsiu-Sen , Shih Dong-Her , Lin Binshan , Shih Ming-Hung
Published: February 2014

Motivation: Changes in the normal rhythm of a human heart may result in different cardiac arrhythmias, which may be immediately fatal or cause irreparable damage to the heart sustained over long periods of time. Therefore, the ability to automatically identify arrhythmias from ECG recordings is important for clinical diagnosis and treatment. In this article, classification by using associative Petri net (APN) for personalized ECG-arrhythmia-pattern identification is proposed for the first time in literature.

Results: A rule-based classification model and reasoning algorithm of APN are created for ECG arrhythmias classification. The performance evaluation using MIT-BIH arrhythmia database shows that our approach compares well with other reported studies.

Contact:  shihdh@yuntech.edu.tw
Magnetic dipole moment of soft gamma-ray repeaters and anomalous X-ray pulsars described as massive and magnetic white dwarfs
Authors: Coelho Jaziel G. , Malheiro Manuel
Published: February 2014

Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) are some of the most interesting groups of pulsars that have been intensively studied in recent years. They are understood as neutron stars (NSs) with super-strong magnetic fields, namely B ≳ 1014 G. However, in the last two years two SGRs with low magnetic fields B ∼ (1012–1013) G have been detected. Moreover, three fast and very magnetic white dwarfs (WDs) have also been observed in recent years. Based on these new pulsar discoveries, we compare and contrast the magnetic fields, magnetic dipole moment, characteristic ages, and X-ray steady luminosities of these two SGRs (in the WD model) with the three fast white dwarfs, to conclude that they show strong similarities corroborating an alternative description of several SGRs/AXPs as very massive and magnetic white dwarfs. We show that the values for m obtained for several SGRs and AXPs are in agreement with the observed range 1034 emu ≤ m ≤ 1036 emu of isolated and polar magnetic white dwarfs. This result, together with the fact that for magnetic white dwarfs B ∼ (106–108) G their magnetic dipole moments are almost independent of the star rotation period (104 s ≲ P ≲ 106 s)—a phenomenology not shared by neutron star pulsars—suggests a possible magnetic white dwarf nature for some SGRs/AXPs that have much smaller periods (P ∼ 10 s). Moreover, since for pulsars the dipole radiation power is proportional only to m and to the rotational star frequency, we can explain in the WD model—considering only the different scales of the magnetic dipole moment for WDs and NSs—why the steady luminosity LX for several SGRs/AXPs (and in particular the low-B SGRs) compared to those of X-ray dim isolated neutron stars (XDINs) and high-B pulsars obeys the ratio LXSGRs/AXPs/LXXDINs ∼ mWD/mNS ∼ 103: all these X-ray sources have essentially the same rotational periods (P ∼ 10 s) and the X-ray luminosity is correlated to the spin-down luminosity, which is equal to the dipole radiation power in the dipole model.
Evaluation of the AtoxigenicAspergillus flavusStrain AF36 in Pistachio Orchards
Authors: Doster Mark A. , Cotty Peter J. , Michailides Themis J.
Published: February 2014

The atoxigenic strain Aspergillus flavus AF36, which has been extensively used as a biocontrol agent in commercial corn and cotton fields to reduce aflatoxin contamination, was applied in research pistachio orchards from 2002 to 2005 and in commercial pistachio orchards from 2008 to 2011. AF36 was applied as hyphae-colonized steam-sterilized wheat seed (the same product and same application rate as used in cotton fields). In all orchards, applying the wheat-AF36 product substantially increased the proportion of vegetative compatibility group (VCG) YV36, the VCG to which AF36 belongs, within A. flavus soil communities. Application of the AF36 product in additional years further increased YV36 in the soil until it composed 93% of the A. flavus isolates in treated commercial orchards. Nonetheless, application of the AF36 product did not result in increased incidence of kernel decay of the nuts. For nuts harvested from commercial orchards, reductions in percentages of samples contaminated with aflatoxin from treated orchards (relative to that for untreated orchards) ranged from 20 to 45%, depending on the year. Because of the high value of pistachio nuts and the costs associated with rejection of shipments due to aflatoxin contamination, these reductions are significant and valuable to the pistachio industry.
Existing and emerging high impact invasive species are characterized by higher functional responses than natives
Authors: Alexander Mhairi E. , Dick Jaimie T. A. , Weyl Olaf L. F. , Robinson Tamara B. , Richardson David M.
Published: February 2014

Predicting ecological impacts of invasive species and identifying potentially damaging future invaders are research priorities. Since damage by invaders is characterized by their depletion of resources, comparisons of the ‘functional response’ (FR; resource uptake rate as a function of resource density) of invaders and natives might predict invader impact. We tested this by comparing FRs of the ecologically damaging ‘world's worst’ invasive fish, the largemouth bass (Micropterus salmoides), with a native equivalent, the Cape kurper (Sandelia capensis), and an emerging invader, the sharptooth catfish (Clarias gariepinus), with the native river goby (Glossogobius callidus), in South Africa, a global invasion hotspot.Using tadpoles (Hyperolius marmoratus) as prey, we found that the invaders consumed significantly more than natives. Attack rates at low prey densities within invader/native comparisons reflected similarities in predatory strategies; however, both invasive species displayed significantly higher Type II FRs than the native comparators. This was driven by significantly lower prey handling times by invaders, resulting in significantly higher maximum feeding rates. The higher FRs of these invaders are thus congruent with, and can predict, their impacts on native communities. Comparative FRs may be a rapid and reliable method for predicting ecological impacts of emerging and future invasive species.
Prior hormetic priming is costly under environmental mismatch
Authors: Costantini David , Monaghan Pat , Metcalfe Neil B.
Published: February 2014

It is increasingly recognized that hormetic environmental priming of stress responses can improve resilience to later life stress exposure. However, such phenotypic adjustments may be costly, particularly if the subsequent environment does not match that to which the adjustment was made. Here, we show that hormetic priming to mild heat stress in early life increases survival only when heat stress is again experienced in adulthood; it reduces survival if the stressor is not encountered again. That such costs can occur explains both why the stress response system is not maintained in an upregulated state and why the hormetic adjustment of responses has evolved.
New parsimonious simulation methods and tools to assess future food and environmental security of farm populations
Authors: Antle John M. , Stoorvogel Jetse J. , Valdivia Roberto O.
Published: February 2014

This article presents conceptual and empirical foundations for new parsimonious simulation models that are being used to assess future food and environmental security of farm populations. The conceptual framework integrates key features of the biophysical and economic processes on which the farming systems are based. The approach represents a methodological advance by coupling important behavioural processes, for example, self-selection in adaptive responses to technological and environmental change, with aggregate processes, such as changes in market supply and demand conditions or environmental conditions as climate. Suitable biophysical and economic data are a critical limiting factor in modelling these complex systems, particularly for the characterization of out-of-sample counterfactuals in
ex ante
analyses. Parsimonious, population-based simulation methods are described that exploit available observational, experimental, modelled and expert data. The analysis makes use of a new scenario design concept called representative agricultural pathways. A case study illustrates how these methods can be used to assess food and environmental security. The concluding section addresses generalizations of parametric forms and linkages of regional models to global models.
Elevating crop disease resistance with cloned genes
Authors: Jones Jonathan D. G. , Witek Kamil , Verweij Walter , Jupe Florian , Cooke David , Dorling Stephen , Tomlinson Laurence , Smoker Matthew , Perkins Sara , Foster Simon
Published: February 2014

Essentially all plant species exhibit heritable genetic variation for resistance to a variety of plant diseases caused by fungi, bacteria, oomycetes or viruses. Disease losses in crop monocultures are already significant, and would be greater but for applications of disease-controlling agrichemicals. For sustainable intensification of crop production, we argue that disease control should as far as possible be achieved using genetics rather than using costly recurrent chemical sprays. The latter imply CO
2
emissions from diesel fuel and potential soil compaction from tractor journeys. Great progress has been made in the past 25 years in our understanding of the molecular basis of plant disease resistance mechanisms, and of how pathogens circumvent them. These insights can inform more sophisticated approaches to elevating disease resistance in crops that help us tip the evolutionary balance in favour of the crop and away from the pathogen. We illustrate this theme with an account of a genetically modified (GM) blight-resistant potato trial in Norwich, using the
Rpi-vnt1.1
gene isolated from a wild relative of potato,
Solanum venturii
, and introduced by GM methods into the potato variety Desiree.
Extreme vulnerability of smallholder farmers to agricultural risks and climate change in Madagascar
Authors: Harvey Celia A. , Rakotobe Zo Lalaina , Rao Nalini S. , Dave Radhika , Razafimahatratra Hery , Rabarijohn Rivo Hasinandrianina , Rajaofara Haingo , MacKinnon James L.
Published: February 2014

Across the tropics, smallholder farmers already face numerous risks to agricultural production. Climate change is expected to disproportionately affect smallholder farmers and make their livelihoods even more precarious; however, there is limited information on their overall vulnerability and adaptation needs. We conducted surveys of 600 households in Madagascar to characterize the vulnerability of smallholder farmers, identify how farmers cope with risks and explore what strategies are needed to help them adapt to climate change. Malagasy farmers are particularly vulnerable to any shocks to their agricultural system owing to their high dependence on agriculture for their livelihoods, chronic food insecurity, physical isolation and lack of access to formal safety nets. Farmers are frequently exposed to pest and disease outbreaks and extreme weather events (particularly cyclones), which cause significant crop and income losses and exacerbate food insecurity. Although farmers use a variety of risk-coping strategies, these are insufficient to prevent them from remaining food insecure. Few farmers have adjusted their farming strategies in response to climate change, owing to limited resources and capacity. Urgent technical, financial and institutional support is needed to improve the agricultural production and food security of Malagasy farmers and make their livelihoods resilient to climate change.