Gould Belt Members in X-ray RAVE: Cross-Matching RAVE Stars with 3XMM Point Sources

In this paper the results of matching the RAdial Velocity Experiment (RAVE), a spectroscopic Southern hemisphere survey (9 $< I_{DENIS} <$ 12), and XMM-Newton Serendipitous Source Catalogue (3XMM) are presented. The latest data releases of RAVE and XMM were matched and a X-ray RAVE catalogue of 1071 stars was obtained. Then the catalogue was checked for possible Gould Belt (GB) members. We obtained a subsample of 10 stars that meet the GB membership criteria. This subsample and GB member candidates were tested photometrically and kinematically. Among the members there are two BY Dra type variables, an NGC2451 open cluster member, a high proper motion star. The rest are regular main sequence stars. The members have very low velocity dispersions which lead us to think that the members belong in a single structure. We also found out that a kinematical GB membership test might be possible to derive given a large enough GB member sample as they fit in a narrow interval in space velocity diagrams.Comment: Accepted by Astrophysics and Space Scienc

Measurements of Gd 152 (p,γ) Tb 153 and Gd 152 (p,n) Tb 152 reaction cross sections for the astrophysical γ process

The total cross sections for the Gd152(p,γ)Tb153 and Gd152(p,n)152Tb reactions have been measured by the activation method at effective center-of-mass energies 3.47≤Ec.m.eff≤7.94 MeV and 4.96≤Ec.m.eff≤7.94 MeV, respectively. The targets were prepared by evaporation of 30.6% isotopically enriched Gd152 oxide on aluminum backing foils, and bombarded with proton beams provided by a cyclotron accelerator. The cross sections were deduced from the observed γ-ray activity, which was detected off-line by an HPGe detector in a low background environment. The results are presented and compared with predictions of statistical model calculations. This comparison supports a modified optical proton+Gd152 potential suggested earlier.Peer reviewedFinal Accepted Versio

Alpha-induced cross sections of 106Cd for the astrophysical p-process

The 106Cd(alpha,gamma)110Sn reaction cross section has been measured in the energy range of the Gamow window for the astrophysical p-process scenario. The cross sections for 106Cd(alpha,n)109Sn and for 106Cd(alpha,p)109In below the (alpha,n) threshold have also been determined. The results are compared with predictions of the statistical model code NON-SMOKER using different input parameters. The comparison shows that a discrepancy for 106Cd(alpha,gamma)110Sn when using the standard optical potentials can be removed with a different alpha+106Cd potential. Some astrophysical implications are discussed.Comment: 10 pages, 9 figures, accepted for publication in Phys. Rev

Seed-derived microbial colonization of Wild Emmer and domesticated bread wheat (Triticum dicoccoides and T. aestivum) seedlings shows pronounced differences in overall diversity and composition

The composition of the plant microbiota may be altered by ecological and evolutionary changes in the host population. Seed-associated microbiota, expected to be largely vertically transferred, have the potential to coadapt with their host over generations. Strong directional selection and changes in the genetic composition of plants during domestication and cultivation may have impacted the assembly and transmission of seed-associated microbiota. Nonetheless, the effect of plant speciation and domestication on the composition of these microbes is poorly understood. Here, we have investigated the composition of bacteria and fungi associated with the wild emmer wheat (Triticum dicoccoides) and domesticated bread wheat (Triticum aestivum). We show that vertically transmitted bacteria, but not fungi, of domesticated bread wheat species T. aestivum are less diverse and more inconsistent among individual plants compared to those of the wild emmer wheat species T. dicoccoides. We propagated wheat seeds under sterile conditions to characterize the colonization of seedlings by seed-associated microbes. Hereby, we show markedly different community compositions and diversities of leaf and root colonizers of the domesticated bread wheat compared to the wild emmer wheat. By propagating the wild emmer wheat and domesticated bread wheat in two different soils, we furthermore reveal a small effect of plant genotype on microbiota assembly. Our results suggest that domestication and prolonged breeding have impacted the vertically transferred bacteria, but only to a lesser extent have affected the soil-derived microbiota of bread wheat.IMPORTANCE Genetic and physiological changes associated with plant domestication have been studied for many crop species. Still little is known about the impact of domestication on the plant-associated microbiota. In this study, we analyze the seed-associated and soil-derived bacterial and fungal microbiota of domesticated bread wheat and wild emmer wheat. We show a significant difference in the seed-associated, but not soil-derived, bacterial communities of the wheat species. Interestingly, we find less pronounced effects on the fungal communities. Overall, this study provides novel insight into the diversity of vertically transmitted microbiota of wheat and thereby contributes to our understanding of wheat as a “}metaorganism.{” Insight into the wheat microbiota is of fundamental importance for the development of improved crops

Proton induced reaction cross section measurements on Se isotopes for the astrophysical p process

As a continuation of a systematic study of reactions relevant to the astrophysical p process, the cross sections of the 74,76Se(p,gamma)75,77Br and 82Se(p,n)82Br reactions have been measured at energies from 1.3 to 3.6 MeV using an activation technique. The results are compared to the predictions of Hauser-Feshbach statistical model calculations using the NON-SMOKER and MOST codes. The sensitivity of the calculations to variations in the optical proton potential and the nuclear level density was studied. Good agreement between theoretical and experimental reaction rates was found for the reactions 74Se(p,gamma)75Br and 82Se(p,n)82Br.Comment: 9 pages, 6 figures (in 12 eps files), accepted for publication in Phys. Rev C, RevTeX styl

Measurements of proton induced reaction cross sections on 120Te for the astrophysical p-process

The total cross sections for the 120Te(p,gamma)121I and 120Te(p,n)120I reactions have been measured by the activation method in the effective center-of-mass energies between 2.47 MeV and 7.93 MeV. The targets were prepared by evaporation of 99.4 % isotopically enriched 120Te on Aluminum and Carbon backing foils, and bombarded with proton beams provided by the FN tandem accelerator at the University of Notre Dame. The cross sections and $S$ factors were deduced from the observed gamma ray activity, which was detected off-line by two Clover HPGe detectors mounted in close geometry. The results are presented and compared with the predictions of statistical model calculations using the codes NON-SMOKER and TALYS.Comment: 17 pages, 5 figures, 5 tables, regular articl

Technical Note: Time lag correction of aquatic eddy covariance data measured in the presence of waves

Extracting benthic oxygen fluxes from eddy covariance time series measured in the presence of surface gravity waves requires careful consideration of the temporal alignment of the vertical velocity and the oxygen concentration. Using a model based on linear wave theory and measured eddy covariance data, we show that a substantial error in flux can arise if these two variables are not aligned correctly in time. We refer to this error in flux as the time lag bias. In one example, produced with the wave model, we found that an offset of 0.25 s between the oxygen and the velocity data produced a 2-fold overestimation of the flux. In another example, relying on nighttime data measured over a seagrass meadow, a similar offset reversed the flux from an uptake of −50 mmol m−2 d−1 to a release of 40 mmol m−2 d−1. The bias is most acute for data measured at shallow-water sites with short-period waves and low current velocities. At moderate or higher current velocities (> 5–10 cm s-1), the bias is usually insignificant. The widely used traditional time shift correction for data measured in unidirectional flows, where the maximum numerical flux is sought, should not be applied in the presence of waves because it tends to maximize the time lag bias or give unrealistic flux estimates. Based on wave model predictions and measured data, we propose a new time lag correction that minimizes the time lag bias. The correction requires that the time series of both vertical velocity and oxygen concentration contain a clear periodic wave signal. Because wave motions are often evident in eddy covariance data measured at shallow-water sites, we encourage more work on identifying new time lag corrections

Triticum dicoccoides: an important genetic resource for increasing zinc and iron concentration in modern cultivated wheat

One major strategy to increase the level of zinc (Zn) and iron (Fe) in cereal crops, is to exploit the natural genetic variation in seed concentration of these micronutrients. Genotypic variation for Zn and Fe concentration in seeds among cultivated wheat cultivars is relatively narrow and limits the options to breed wheat genotypes with high concentration and bioavailability of Zn and Fe in seed. Alternatively, wild wheat might be an important genetic resource for enhancing micronutrient concentrations in seeds of cultivated wheat. Wild wheat is widespread in diverse environments in Turkey and other parts of the Fertile Crescent (e.g., Iran, Iraq, Lebanon, Syria, Israel, and Jordan). A large number of accessions of wild wheat and of its wild relatives were collected from the Fertile Crescent and screened for Fe and Zn concentrations as well as other mineral nutrients. Among wild wheat, the collections of wild emmer wheat, Triticum turgidum ssp. dicoccoides (825 accessions) showed impressive variation and the highest concentrations of micronutrients, significantly exceeding those of cultivated wheat. The concentrations of Zn and Fe among the dicoccoides accessions varied from 14 to 190 mg kg(-1) DW for Zn and from 15 to 109 mg kg(-1) DW for Fe. Also for total amount of Zn and Fe per seed, dicoccoides accessions contained very high amount of Zn (up to 7 mug per seed) and Fe (up to 3.7 mug per seed). Such high genotypic variation could not be found for phosphorus, magnesium, and sulfur. In the case of modern cultivated wheat, seed concentrations of Zn and Fe were lower and less variable when compared to wild wheat accessions. There was a highly significant positive correlation between seed concentrations of Fe and Zn. Screening different series of dicoccoides substitution lines revealed that the chromosome 6A, 6B, and 5B of dicoccoides resulted in greater increase in Zn and Fe concentration when compared to their recipient parent and to other chromosome substitution lines. The results indicate that Triticum turgidum L. var. dicoccoides (wild emmer) is an important genetic resource for increasing concentration and content of Zn and Fe in modern cultivated wheat

Odd p isotope 113In: Measurement of alpha-induced reactions

One of the few p nuclei with an odd number of protons is 113In. Reaction cross sections of 113In(alpha,gamma)117Sb and 113In(alpha,n)116Sb have been measured with the activation method at center-of-mass energies between 8.66 and 13.64 MeV, close to the astrophysically relevant energy range. The experiments were carried out at the cyclotron accelerator of ATOMKI. The activities were determined by off-line detection of the decay gamma rays with a HPGe detector. Measured cross sections and astrophysical S factor results are presented and compared with statistical model calculations using three different alpha+nucleus potentials. The comparison indicates that the standard rates used in the majority of network calculations for these reactions were too fast due to the energy dependence of the optical alpha potential at low energy.Comment: 9 pages, 9 figures, Accepted for publication in Phys. Rev. C. Minor changes mad

Keyframe reduction techniques for motion capture data

Two methods for keyframe reduction of motion capture data are presented. Keyframe reduction of motion capture data enables animators to easily edit motion data with smaller number of keyframes. One of the approaches achieves keyframe reduction and noise removal simultaneously by fitting a curve to the motion information using dynamic programming. The other approach uses curve simplification algorithms on the motion capture data until a predefined threshold of number of keyframes is reached. Although the error rate varies with different motions, the results show that curve fitting with dynamic programming performs as good as curve simplification methods. ©2008 IEEE