bluuebunny/crossref_metadata_2025_split huggingface dataset:
Introduction & Overview to Symposium 240: Binary Stars as Critical Tools and Tests in Contemporary Astrophysics
Authors: Guinan Edward F. , Harmanec Petr , Hartkopf William 
Published: July 2007

AbstractAn overview is presented of the many new and exciting developments in binary and multiple star studies that were discussed at IAU Symposium 240. Impacts on binary and multiple star studies from new technologies, techniques, instruments, missions and theory are highlighted. It is crucial to study binary and multiple stars because the vast majority of stars (>60%) in our Galaxy and in other galaxies consist, not of single stars, but of double and multiple star systems. To understand galaxies we need to understand stars, but since most are members of binary and multiple star systems, we need to study and understand binary stars. The major advances in technology, instrumentation, computers, and theory have revolutionized what we know (and also don't know) about binary and multiple star systems. Data now available from interferometry (with milliarcsecond [mas] and sub-mas precisions), high-precision radial velocities (∼1-2 m/s) and high precision photometry (<1–2 milli-mag) as well as the wealth of new data that are pouring in from panoramic optical and infrared surveys (e.g., > 10,000 new binaries found since 1995), have led to a renaissance in binary star and multiple star studies. For example, advances have lead to the discovery of new classes of binary systems with planet and brown dwarf components (over 200 systems). Also, extremely valuable data about binary stars are available across the entire electromagnetic spectrum — from gamma-ray to IR space missions and from the ground using increasingly more powerful and plentiful optical and radio telescopes as well as robotic telescopes. In the immediate future, spectral coverage could even be extended beyond the radio to the first detection of gravity waves from interacting close binaries. Also, both the quality and quantity of data now available on binary and multiple stars are making it possible to gain unprecedented new insights into the structure, and formation and evolution of binary stars, as well as providing valuable astrophysical information (like precise stellar masses, radii, ages, luminosities and distances) to test and constrain current astrophysical theory. These major advances permit tests of current theories and ideas in stellar astrophysics and provide the foundations for the next steps in modeling and improvements in theory to be taken.
Eclipsing Binaries: Tools for Calibrating the Extragalactic Distance Scale
Authors: Bonanos Alceste Z. 
Published: July 2007

AbstractIn the last decade, over 7000 eclipsing binaries have been discovered in the Local Group through various variability surveys. Measuring fundamental parameters of these eclipsing binaries has become feasible with 8 meter class telescopes, making it possible to use eclipsing binaries as distance indicators. Distances with eclipsing binaries provide an independent method for calibrating the extragalactic distance scale and thus determining the Hubble constant. This method has been used for determining distances to eclipsing binaries in the Magellanic Clouds and the Andromeda Galaxy and most recently to a detached eclipsing binary in the Triangulum Galaxy by the DIRECT Project. The increasing number of eclipsing binaries found by microlensing and variability surveys also provide a rich database for advancing our understanding of star formation and evolution.
Toward a Common Language: the Washington Multiplicity Catalog
Authors: Hartkopf William I. 
Published: July 2007

AbstractDue to improvements in technology (interferometers, precision radial-velocity techniques, etc.), the traditional separation/period regimes of “wide” and “close” binaries are witnessing increasing overlap. This is expected to lead to increasing confusion in component identification, since different observing techniques adopted their own rules for designation of these components. A quick overview will be given of the Washington Multiplicity Catalog, an effort to create a common nomenclature scheme for all types of stellar and sub-stellar companions.
Polaris: Mass and Multiplicity
Authors: Evans Nancy Remage , Schaefer Gail , Bond Howard E. , Nelan Edmund , Bono Giuseppe , Karovska Margarita , Wolk Scott , Sasselov Dimitar , Guinan Edward , Engle Scott , Schlegel Eric , Mason Brian 
Published: July 2007

AbstractPolaris, the nearest and brightest classical Cepheid, is a member of at least a triple system. It has a wide (18″) physical companion, the F-type dwarf Polaris B. Polaris itself is a single-lined spectroscopic binary with an orbital period of ∼30 years (Kamper 1996). By combining Hipparcos measurements of the instantaneous proper motion with long-term measurements and the Kamper radial-velocity orbit, Wielen et al (2000) have predicted the astrometric orbit of the close companion. Using the Hubble Space Telescope and the Advanced Camera for Surveys' High-Resolution Channel with an ultraviolet (F220W) filter, we have now directly detected the close companion. Based on the Wielen et al orbit, the Hipparcos parallax, and our measurement of the separation (0″.176 ± 0″.002), we find a preliminary mass of 5.0 ± 1.5 M⊙ for the Cepheid and 1.38 ± 0.61 M⊙ for the close companion. These values will be refined by additional HST observations scheduled for the next 3 years.We have also obtained a Chandra ACIS-I image of the Polaris field. Two distant companions C and D are not X-rays sources and hence are not young enough to be physical companions of the Cepheid. There is one additional stellar X-ray source in the field, located 253″ from Polaris A, which is a possible companion. Further investigation of such a distant companion is valuable to confirm the full extent of the system.
Binary Stars in the Orion Nebula Cluster
Authors: Köhler Rainer , Petr-Gotzens Monika G. , McCaughrean Mark J. , Bouvier Jerome , Duchêne Gaspard , Quirrenbach Andreas , Zinnecker Hans 
Published: July 2007

AbstractWe report on a high-spatial-resolution survey for binary stars in the periphery of the Orion Nebula Cluster, at 5–15 arcmin (0.65 – 2 pc) from the cluster center. We observed 228 stars with adaptive optics systems, in order to find companions at separations of 0.13 – 1.12 arcsec (60 – 500 AU), and detected 13 new binaries. Combined with the results of Petr (1998), we have a sample of 275 objects, about half of which have masses from the literature and high probabilities to be cluster members. We used an improved method to derive the completeness limits of the observations, which takes into account the elongated point spread function of stars at relatively large distances from the adaptive optics guide star. The multiplicity of stars with masses >2 M⊙ is found to be significantly larger than that of low-mass stars. The companion star frequency of low-mass stars is comparable to that of main-sequence M-dwarfs, less than half that of solar-type main-sequence stars, and 3.5 to 5 times lower than in the Taurus-Auriga and Scorpius-Centaurus star-forming regions. We find the binary frequency of low-mass stars in the periphery of the cluster to be the same or only slightly higher than for stars in the cluster core (< 3′ from θ1C Ori). This is in contrast to the prediction of the theory that the low binary frequency in the cluster is caused by the disruption of binaries due to dynamical interactions. There are two ways out of this dilemma: Either the initial binary frequency in the Orion Nebula Cluster was lower than in Taurus-Auriga, or the Orion Nebula Cluster was originally much denser and dynamically more active. A detailed report of this work has been published in Astronomy & Astrophysics (Köhler et al. 2006).
Detectability of Planets in Wide Binaries by Ground-Based Relative Astrometry with AO
Authors: Neuhäuser R. , Seifahrt A. , Röll T. , Bedalov A. , Mugrauer M. 
Published: July 2007

AbstractMany planet candidates have been detected by radial-velocity variations of the primary star; they are planet candidates, because of the unknown orbit inclination. Detection of the wobble in the two other dimensions, to be measured by astrometry, would yield the inclination and, hence, true mass of the companions. We aim to show that planets can be confirmed or discovered in a close visual stellar binary system by measuring the astrometric wobble of the exoplanet host star as a periodic variation of the separation, even from the ground. We test the feasibility with HD 19994, a visual binary with one radial velocity planet candidate. We use the adaptive optics camera NACO at the VLT with its smallest pixel scale (∼ 13 mas) for high-precision astrometric measurements. The separations measured in 120 single images taken within one night are shown to follow white noise, so that the standard deviation can be divided by the square root of the number of images to obtain the precision. In this paper we present the first results and investigate the achievable precision in relative astrometry with adaptive optics. With careful data reduction it is possible to achieve a relative astrometric precision as low as 50 μ as for a 0″.6 binary with VLT/NACO observations in one hour, the best relative astrometric precision ever achieved with a single telescope from the ground. The relative astrometric precision demonstrated here with AO at an 8-m mirror is sufficient to detect the astrometric signal of the planet HD 19994 Ab as periodic variation of the separation between HD 19994 A and B.
Measurement of the Tidal Dissipation in Multiple Stars
Authors: Tokovinin Andrei 
Published: July 2007

AbstractConsiderable effort has been spent to determine the period of tidal circularization in close binaries as a function of age, in order to constrain the tidal dissipation theory. A new, direct method of measuring the tidal dissipation by precise timings of periastron passages in eccentric binaries undergoing circularization is proposed. Such binaries with components just leaving the Main Sequence can be found as inner systems in multiple stars. Three examples are given.
Testing and Improving the Dynamical Theory of Mass Exchange
Authors: Bisikalo Dmitry , Matsuda Takuya 
Published: July 2007

AbstractThe study of the flow structure is of great importance, and the results can be used both for consideration of the evolutionary status of binary stars and for the interpretation of observational data. In this report we present the review of 3D gas dynamic models used for the description of the mass exchange in close binaries.Main features of the flow structure in steady-state close binaries are summarized. It is shown that in self-consistent considerations the interaction between the stream from the inner Lagrangian point and the forming accretion disk is shock-free, and, hence, a “hot spot” does not form at the outer edge of the disk. To explain the presence of the observed zones of high luminosity in close binaries a self-consistent “hot line” model was proposed according to which the excess energy is released in a shock wave formed due to interaction between the circumdisk halo and the stream. The “hot line” model was confronted with observations and confirmed by virtue of comparison of synthetic and observational light curves for cataclysmic variables and by the analysis of Doppler tomograms.The special attention is paid to the physics of accretion disks in binary systems and particularly to waves in disks. The possible observational manifestations of the “hot line” wave and two arms of the tidal shocks are discussed. We also suggest that an additional spiral density wave can exist in inner parts of the cold accretion disk. This spiral wave is due to the retrograde precession of flow lines in the binary system. The results of 3D gas dynamic simulation have shown that a considerable increase in the accretion rate (by an order of magnitude) is associated with the formation of the “precessional” spiral wave. Based on this fact we suggest a new mechanism for the superoutbursts and superhumps in close binaries.
Close Pairs as Probes of the Galaxy's Chemical Evolution
Authors: Vanbeveren Dany , De Donder Erwin 
Published: July 2007

AbstractUnderstanding the galaxy in which we live is one of the great intellectual challenges facing modern science. With the advent of high quality observational data, the chemical evolution modeling of our galaxy has been the subject of numerous studies in the last years. However, all these studies have one missing element which is ‘the evolution of close binaries’. Reason: their evolution is very complex and single stars only perhaps can do the job. (Un)Fortunately at present we know that a significant fraction of the observed intermediate mass and massive stars are members of a binary or multiple system and that certain objects can only be formed through binary evolution. Therefore galactic studies that do not account for close binaries may be far from realistic. We implemented a detailed binary population in a galactic chemical evolutionary model. Notice that this is not something simple like replacing chemical yields. Here we discuss three topics: the effect of binaries on the evolution of 14N, the evolution of the type Ia supernova rate and the effects on the G-dwarf distribution, the link between the evolution of the r-process elements and double neutron star mergers (candidates of short gamma-ray burst objects).
Halo Wide Binaries and Moving Clusters as Probes of the Dynamical and Merger History of our Galaxy
Authors: Allen Christine , Poveda Arcadio , Hernández-Alcántara A. 
Published: July 2007

AbstractWide or fragile pairs are sensitive probes of the galactic potential, and they have been used to provide information about the galactic tidal field, the density of GMC and the masses of dark matter perturbers present in both the disk and the halo. Halo wide binaries and moving clusters, since they are likely to be the remains of past mergers or of dissolved clusters, can provide information on the dynamical and merger history of our Galaxy. Such remnants should continue to show similar motions over times of the order of their ages. We have looked for phase space groupings among the low-metallicity stars of Schuster et al (2006) and have identified a number of candidate moving clusters. In several of the moving clusters we found a wide CPM binary already identified in our catalogue of wide binaries among high-velocity and metal-poor stars (Allen et al 2000a). Spectroscopic follow-up studies of these stars would confirm the physical reality of the groups, as well as allow us to distinguish whether their progenitors are dissolved clusters or accreted extragalactic systems.
First Report of Botrytis Blight Caused by Botrytis cinerea on Sweet Basil in Hungary
Authors: Nagy G. 
Published: July 2007

In Hungary, sweet basil (Ocimum basilicum L.) is an important medicinal and aromatic plant cultivated over a large area. During field surveys conducted in August and September of 2001 and 2002, significant blossom and leaf blight were observed in plant stands located near Budapest and in the northern region of Hungary at Herencsény. Incidence of disease occurrence ranged between 49 and 92%. Abundant grayish-brown mold consisting of mycelia and conidiophores was observed on necrotic flowers and upper leaves. The fungus was identified as Botrytis cinerea Pers.:Fr.. Conidia were one-celled, ovoid to elliptical, and measured 11.2 × 7.4 μm (7.5 to 15.0 × 5.0 to 10.0 μm). The fungus was isolated on Leonian malt media. In culture, small and large irregular sclerotia, as well as conidiophores, were produced abundantly. Size of large sclerotia ranged between 45 and 95 mm. Sclerotia were produced only in culture. Pathogenicity of two isolates originating from Herencsény was confirmed by spraying eight sweet basil potted plants with a conidial suspension (6.3 × 105 conidia/ml) made from a pure culture. Two noninoculated plants served as controls. Half of the plants were wounded with needles to make incisions on the leaves and flower axes prior to the inoculation, while the remaining plants were directly sprayed. After inoculation, plants were kept in plastic bags in a greenhouse to maintain 90 to 100% relative humidity at 15 to 40°C. After 5 days, water-soaked chlorotic lesions appeared on the wounded leaves of the inoculated plants. After day 12, brown necrosis developed on the flowers of all inoculated plants. Flower axes often broke. Sporulation of the fungus was abundant. Wounding contributed to earlier appearance of the symptoms and more intensive disease development. To our knowledge, this is the first report of botrytis blight on sweet basil in Hungary. In Europe, the disease has been observed in Italy (1) and Greece (2). References: (1) A. Garibaldi et al. Plant Dis. 81:124, 1997. (2) C. D. Holevas et al. Benaki Phytopathol. Inst. Kiphissia, Athens 19:1, 2000.
The response of Chironomidae to sediment pollution and other environmental characteristics in urban wetlands
Authors: CAREW MELISSA E. , PETTIGROVE VINCENT , COX RENEE L. , HOFFMANN ARY A. 
Published: July 2007

Summary1. We investigated the distribution of chironomid taxa in urban wetlands in the greater Melbourne area, Australia, to test if their distribution was influenced by sediment pollution and other environmental variables.2. For identification of the Chironomidae, DNA markers generated via polymerase chain reaction–restriction fragment length polymorphism of cytochrome c oxidase sub unit I (COI) were validated against morphology and reference specimens for more than 5000 chironomids representing over 80 species. DNA‐based identification generally concurred with morphological separation, but also indicated the existence of cryptic diversity in some genera.3. Non‐metric multidimensional scaling (NMS) and canonical correspondence analysis (CCA) showed chironomid assemblages were structured among wetlands and could be linked to several habitat characteristics. However, Chironomidae assemblages were only weakly linked to sediment pollution.4. Logistic regressions identified potential bioindicators of sediment pollution. Riethia stictoptera, Tanytarsus inextentus, Coelopynia and Chironomus ‘februarius’ were negatively associated and Chironomus duplex was positively associated with sediment pollution. Thresholds for the pollution sensitivities of specific species were mostly similar to those established with previous microcosm tests.5. Several other environmental factors influenced the distribution of specific chironomid taxa. Salinity, substratum type and submerged and riparian vegetation were particularly important.6. We conclude that specific chironomid taxa rather than assemblages have potential as bioindicators of sediment pollution provided their ecological preferences are considered and their pollution sensitivities are characterized using multiple methods. The integration of DNA‐based techniques should facilitate accurate and rapid identification of bioindicators species.
Phenotype – genotype correlation in eight Polish patients with inherited Factor XIII deficiency: identification of three novel mutations
Authors: IVASKEVICIUS V. , WINDYGA J. , BARAN B. , SCHROEDER V. , JUNEN J. , BYKOWSKA K. , SEIFRIED E. , KOHLER H. P. , OLDENBURG J. 
Published: July 2007

Summary. Inherited factor XIII (FXIII) deficiency is known as one of the most rare blood coagulation disorder in humans. In the present study, phenotype and genotype of eight FXIII deficient Polish patients from five unrelated families were compared. The patients presented with a severe phenotype demonstrated by a high incidence of intracerebral haemorrhages (seven of eight patients), haemarthrosis (six patients) and bleeding due to trauma (five patients). Introduction of regular substitution with FXIII concentrate prevented spontaneous bleeding in seven patients. In all patients, mutations within the F13A gene have been identified revealing four missense mutations (Arg77Cys, Arg260Cys, Ala378Pro, Gly420Ser), one nonsense mutation (Arg661X), one splice site mutation (IVS5‐1 G>A) and one small deletion (c.499–512del). One homozygous large deletion involving exon 15 was detected by failure of PCR product. The corresponding mutations resulted in severely reduced FXIII activity and FXIII A‐subunit antigen concentration, while FXIII B‐subunit antigen remained normal or mildly decreased. Structural analysis demonstrated that the novel Ala378Pro mutation may cause a disruption of the FXIII catalytic triad leading to a non‐functional protein which presumably undergoes premature degradation. In conclusion, the severe phenotype with high incidence of intracranial bleeding and haemarthrosis was in accordance with laboratory findings on FXIII and with severe molecular defects of the F13A gene.
Clostridium difficile colitis in cystic fibrosis patients with and without lung transplantation
Authors: Theunissen C. , Knoop C. , Nonhoff C. , Byl B. , Claus M. , Liesnard C. , Estenne M.J. , Struelens M.J. , Jacobs F. 
Published: July 2007

Background. Despite a large carriage rate of Clostridium difficile among cystic fibrosis (CF) patients, C. difficile‐associated disease (CDAD) is rather rare. In case of lung transplantation, the incidence and clinical aspects of CDAD in this patient population are not well known.Methods. We reviewed the medical files of all CF patients who presented with symptomatic C. difficile infection from January 1998 to December 2004 and compared the incidence, clinical aspects, severity of disease, and clinical outcome between non‐transplanted and transplanted CF patients.Results. Between 1998 and 2004, 106 adult CF patients were followed at our clinic. Forty‐nine patients underwent lung transplantation; 15 before 1998 and 34 after 1998. The incidence density of CDAD was higher in transplanted CF patients as compared with non‐transplanted CF patients (24.2 vs. 9.5 episodes/100,000 patient‐days; risk ratio: 2.93 [1.41–6.08]; P=0.0044). Diarrhea was a very frequent feature, but was notably absent in 20% of the cases. Rates of moderate and severe colitis were similar in both groups. However, only transplanted patients developed complicated colitis. CT scan and endoscopy were performed more frequently in the transplant group. Two transplant recipients died because of CDAD.Conclusion. CF patients who undergo lung transplantation are at a higher risk of developing CDAD and seem to present more often atypical and/or complicated disease. CDAD should be part of the differential diagnosis in case of digestive symptoms, even in the absence of diarrhea, and requires early treatment.