HS 2333 + 3927: a new sdB binary with a large reflection effect

We report the discovery of a binary, HS 2233 + 3927, consisting of an sdB star with a faint companion. From its lightcurve the orbital period of 14,844 s, the mass ratio, the inclination, and other system parameters are derived. The companion does not contribute to the optical light of the system except through a strong reflection effect. The semi-amplitude of the radial velocity curve K ₁= 89.6 km/s^?1 and a mass function of f(m) = 0.013 M _⊙ are determined. A preliminary spectroscopic analysis of the blue spectra using NLTE model atmospheres results in T_eff= 36 500 K, log g= 5.70, and log(n _He/n _H) =?2.15. These parameters are typical for sdB stars, the companion is probably an M dwarf.     

Back to the future: science and technology directions for radio telescopes of the twenty-first century

The early days of radio astronomy showed incredibly diverse experimentation in ways to sample the electromagnetic spectrum at radio wavelengths. In addition to obtaining adequate sensitivity by building large collection areas, a primary goal also was to achieve sufficient angular resolution to localize radio sources for multi-wavelength identification. This led to many creative designs and the invention of aperture synthesis and VLBI. Some of the basic telescope types remain to the present day, now implemented across the entire radio spectrum from wavelengths of tens of meters to submillimeter wavelengths. In recent years, as always, there is still the drive for greater sensitivity but a primary goal is now to achieve very large fields of view to complement high resolution and frequency coverage, leading to a new phase of experimentation. This is the “back to the future” aspect of current research and development for next-generation radio telescopes. In this paper I summarize the scientific motivations for development of new technology and telescopes since about 1990 and going forward for the next decade and longer. Relevant elements include highly optimized telescope optics and feed antenna designs, innovative fabrication methods for large reflectors and dipole arrays, digital implementations, and hardware vs. software processing. The emphasis will be on meter and centimeter wavelength telescopes but I include a brief discussion of millimeter wavelengths to put the longer wavelength enterprises into perspective. I do not discuss submillimeter wavelengths because they are covered in other papers.     

Die Grippe und ihre Beziehung zu atmosphärischen Einflüssen

Zusammenfassung Eine Beteiligung atmosphärischer Einflüsse bei der Entstehung von Grippeepidemien kann als gesichert angenommen werden. In der Literatur wird jedoch einerseits antizyklonales Wetter, andererseits zyklonales Störungswetter als Grippewetter angegeben; eine eindeutige Beziehung ist also nicht zu erkennen. Auf Grund einer Grippestatistik der Winter 1949 bis 1953 wird dieser Frage erneut nachgegangen.Beim Meteorotropismus der Grippeepidemien sind drei Phasen zu unterscheiden: a) die Entstehung der Epidemie, b) deren weiterer Verlauf und c) die großräumige Wanderung der Epidemie (Seuchenzug).Als Ergebnis der vorliegenden Untersuchung werden folgende Zusammenhänge festgestellt. Voraussetzung für das Entstehen einer Grippeepidemie ist ein atmosphärisches Milieu, wie es sich in stationären winterlichen Antizyklonen ausbildet. Einer solchen grippefördernden Hochdrucklage folgendes zyklonales Störungswetter führt infolge der meteorotropen Belastungen des Organismus zu weiteren Erkrankungen und somit zu einer plötzlichen Steigerung der Epidemie. Ohne vorherige Ausbildung des antizyklonalen Milieus wirkt das zyklonale Störungswetter jedoch nicht als Grippewetter. Die weltweiten Seuchenzüge der Grippe sind nicht als eine Wanderung der Grippe selbst aufzufassen, sondern eine Grippeepidemie entsteht immer wieder dort von neuem, wo das langsam wandernde stationäre Hochdruckgebiet das einer winterlichen Antizyklone eigentümliche atmosphärische Milieu ausbildet. Die entwickelten Vorstellungen werden durch Ergebnisse der Virusforschung gestützt.

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Summary It is a matter of fact that atmospheric influences play an important role for the development of influenza epidemics. In the literature there is found anticyclonic weather on the one hand, and cyclonic perturbations on the other, as being influenza weather, so that a clear theory cannot be developed. On the basis of influenza statistics of the winters 1949 to 1953 this question is investigated once more.Three phases can be distinguished in the meteorotropism of an influenza epidemic: (a) the formation of the epidemic, (b) its sequel, and, (c) its large-scale propagation. The following connexions resulted from this investigation. A certain atmospheric state, as it occurs in stationary anticyclones in winter, is a condition for the genesis of an influenza epidemic. A cyclonic weather perturbation succeeding such a high pressure situation favourable for influenza, because of the meteorotropic stress of the organism, leads to further infections and therefore to a sudden increase of the epidemic. Without the previous development of an anticyclonic milieu the cyclonic perturbation would not work as influenza weather. The world-wide propagation of influenza epidemics cannot be taken in the sense of a migration of the influenza itself, but it always is created anew where the slow drift of a stationary high pressure area forms the characteristic atmospheric milieu of a winter anticyclone. The ideas developped in this article are supported by the investigations of virus research.

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Résumé C'est un fait assuré que des influences atmosphériques participent au déclenchement d'épidémies de grippe. Dans la littérature cependant, on désigne tantôt des situations anticycloniques tantôt des pertubations cycloniques comme temps de grippe. On ne peut donc reconnaître de rapport défini. Cet article reprend ce problème, en se basant sur une statistique de grippe établie pendant les hivers de 1949 à 1953.On peut distinguer trois phases dans le météorotropisme des épidémies de grippe: a) Déclenchement de l'épidémie, b) son développement ultérieur et c) sa propagation à grande échelle. Au cours de cette étude on a pu établir les relations suivantes: Pour déclencher l'épidémie, il faut avant tout que règne un milieu atmosphérique tel qu'il se développe dans les anticyclones stationnaires hivernaux. Si à une telle situation de haute pression favorable à la grippe, suit un régime de perturbations cycloniques, le météorotropisme met l'organisme à telle contribution que de nouveaux cas de maladies surgissent et provoquent un accroissement brusque de l'épidémie. Si, auparavant, il ne s'est pas formé ledit milieu anticyclonique, le régime de pertubations cycloniques n'agit pas comme temps de grippe. La propagation parfois mondiale de ces épidémies ne doit pas être considérée comme une progression de la maladie elle-même, bien plus, de nouvelles épidémies surgissent toujours à nouveau aux endroits-même ou, tout en se déplaçant lentement, l'aire de haute pression établit le milieu atmosphérique particulier aux anticyclones hivernaux. Les recherches faites sur les virus soutiennent les idées développées dans cet article.

     

The influence of geological, geochemical, and biogenic habitat heterogeneity on seep biodiversity

Cold seeps are among the most heterogeneous of all continental margin habitats. Abiotic sources of heterogeneity in these systems include local variability in fluid flow, geochemistry, and substrate type, which give rise to different sets of microbial communities, microbial symbiont-bearing foundation species, and associated heterotrophic species. Biogenic habitats created by microbial mats and the symbiotic species including vesicomyid clams, bathymodiolin mussels, and siboglinid tubeworms add an additional layer of complexity to seep habitats. These forms of habitat heterogeneity result in a variety of macrofaunal and meiofaunal communities that respond to changes in structural complexity, habitat geochemistry, nutrient sources, and interspecific interactions in different ways and at different scales. These responses are predicted by a set of theoretical metacommunity models, the most appropriate of which for seep systems appears to be the 'species sorting' concept, an extension of niche theory. This concept is demonstrated through predictable patterns of community assembly, succession, and beta-level diversity. These processes are described using a newly developed analytical technique examining the change in the slope of the species accumulation curve with the number of habitats examined. The diversity response to heterogeneity has a consistent form, but quantitatively changes at different seep sites around the world as the types of habitats present and the size-classes of fauna analyzed change. The increase in beta diversity across seep habitat types demonstrates that cold seeps and associated biogenic habitats are significant sources of heterogeneity on continental margins globally.     

Arecibo timing and single-pulse observations of 17 pulsars

We have analysed the soft X-ray emission in a wide area of the Sculptor supercluster by using overlapping ROSAT Position Sensitive Proportional Counter pointings. After subtraction of the point sources, we have found evidence for extended, diffuse soft X-ray emission. We have investigated the nature of such extended emission through the cross-correlation with the density of galaxies as inferred from the Münster Redshift Survey. In particular, we have analysed the correlation as a function of the temperature of the X-ray emitting gas. We have found a significant correlation of the galaxy distribution only with the softest X-ray emission (0.1 – 0.3 keV) and only for gas temperatures   kT < 0.5 keV  . We have excluded the fact that this soft X-ray diffuse emission, and its correlation with the galaxy distribution, is significantly contributed by unresolved active galactic nuclei, groups of galaxies or individual galaxies. The most likely explanation is that the soft, diffuse X-ray emission is tracing warm–hot intergalactic medium, with temperatures below 0.5 keV, associated with the large-scale structures in the Sculptor supercluster.     

Patterns of growth in cold-seep vestimenferans including Seepiophila jonesi: a second species of long-lived tubeworm

Seepiophila jonesi is a vestimentiferan tubeworm (Siboglinidae: Polychaeta) inhabiting the cold seeps of the upper slope of the Gulf of Mexico. It commonly co‐occurs with Lamellibrachia luymesi, which is among the most long‐lived non‐clonal animals known. The growth pattern of S. jonesi is best described by a model including a size‐specific probability of growth and an average growth rate that does not vary with individual size. This model, based on growth data from in situ staining and collection approximately 1 year later, predicts that S. jonesi is very slow growing and may attain ages comparable with L. luymesi. The efficacy of this model in describing L. luymesi growth rate was assessed, but the previously employed model of declining growth rate with individual size provided the better fit to the empirical data. Comparisons of both S. jonesi and L. luymesi growth rates among sites and among aggregations within a site indicate that there is some degree of habitat variability contributing to differences in growth rates. However, position of the anterior end of the worm within an aggregation did not have a significant effect on growth rate in comparisons among groups of L. luymesi from different distances from the center of an aggregation. The evolution of longevity in these species of vestimentiferans was favored by the relative stability of the seep habitat and sulfide sources, in contrast to the hydrothermal vent environment inhabited by relatively short‐lived and fast‐growing vestimentiferan species.     

白云鄂博地区碳酸岩墙及岩墙旁侧石英岩中的包裹体研究

白云鄂博的碳酸岩墙中包裹体类型有多子晶包裹体、两相水溶液包裹体、含CO_2三相包裹体和含子晶三相包裹体,岩相学和显微测温结果表明,这些包裹体与国外典型的碳酸岩中的包裹体具有很大程度的一致性,反映了其岩浆成因特点;碳酸岩墙中旁侧的白云鄂博H2石英岩中含有大量的流体包裹体,主要类型为NaCl-H_2O包裹体、CO_2包裹体和H_2O±CO_2±固体的包裹体。包裹体的岩相学、显微测温、阴极发光特征、包裹体成分ICP-MS测定,激光拉曼研究等,揭示出石英岩中的包裹体捕获了来自碳酸岩墙的碳酸岩浆流体,提供了一种不可多得的直接研究碳酸岩流体的手段。