Ultra-Luminous X-ray Sources: Evidence for Very Efficient Formation of Population III Stars Contributing to the Cosmic Near-Infrared Background Excess?

Accumulating evidence indicates that some of ultra-luminous X-ray sources (ULXs) are intermediate mass black holes (IMBHs), but the formation process of IMBHs is unknown. One possibility is that they were formed as remnants of population III (Pop III) stars, but it has been thought that the probability of being an ULX is too low for IMBHs distributed in galactic haloes to account for the observed number of ULXs. Here we show that the number of ULXs can be explained by such halo IMBHs passing through a dense molecular cloud, if Pop III star formation is very efficient as recently suggested by the excess of the cosmic near-infrared background radiation that cannot be accounted for by normal galaxy populations. We calculate the luminosity function of X-ray sources in our scenario and find that it is consistent with observed data. Our scenario can explain that ULXs are preferentially found at outskirts of large gas concentrations in star forming regions. A few important physical effects are pointed out and discussed, including gas dynamical friction, radiative efficiency of accretion flow, and radiative feedback to ambient medium. ULXs could last for ~10^{5-6} yr to emit a total energy of ~10^{53} erg, which is sufficient to power the ionized expanding nebulae found by optical observations.Comment: 6 pages, 1 figures, accepted to ApJ main journal, with extended discussions. Main conclusions unchange

Vibrational assignments and line shapes in inelastic tunnelling spectroscopy: H on Cu(100)

We have carried out a computational study of the inelastic electron tunneling spectrum (IETS) of the two vibrational modes of a single hydrogen atom on a Cu(100) surface in a scanning tunneling microscopy (STM) junction. This study addresses key issues about vibrational assignment and line shape of observed peaks in IETS within the framework of density functional theory calculations and the Lorente-Persson theory for STM-IETS. We argue that the observation of only a single, broad peak in the STM-IETS [L.J. Lauhon and W. Ho, Phys. Rev. Lett. 85, 4566 (2000)] is not caused by any symmetry restrictions or any cancellation between inelastic and elastic vibrational contributions for one of the two modes but is due to strongly overlapping superposition of the contributions from the two modes caused by the rather large instrumental broadening and the narrow vibrational energy separation between the modes. In particular, we find that this broadening and the large asymmetry of the vibrational line shapes gives rise to substantial apparent vibrational energy shifts of the two modes and decrease their apparent energy separation

Detection of exchange interaction in STM measurements through Fanolike interference effects

We address Fano-like interference effects in scanning tunneling microscopy (STM) measurements of nanoscale systems, e.g. two-level systems. Common for these systems is that second order tunneling contributions give rise to interference effects that cause suppressed transmission through the system for certain energies. The suppressed transmission is measurable either in the differential conductance or in the bias voltage derivative thereof.Comment: 9 pages, 3 figures, submitted: in addition to the results published in Phys. Rev. B, 75, 153309 (2007), this paper contains a more thorough discussion on the used transport formalism, studies of asymmetric couplings to the substrate, and discussion of non-resonant levels. The non-resonant case is related to spin-dependent tunnelin

Occurrence of Enzyme Systems for Production and Decomposition of Oxalate in a White-Rot Fungus Coriolus versicolor and Some Characteristics of Glyoxylate Oxidase

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました

ガソリンエンジンの排気ガスを改質剤とする燃料改質用Ni系触媒の開発

Tohoku University冨重圭一課

Veranderungen der Zellen im subkutanen Bindegewebe der Maus bel der Injektion von Arzneimitteln. : V. Versuche mit Moroscher Tuberkulinsalbe.

1. Bei den durch Tuberkulininjektion sensibilisierten weiBen Mausen hat das Einreiben der Moroschen Tuberkulinsalbe in die Haut eine fruhere und starkere Leukozytenvermehrung im Subkutangewebe zur Folge als bei den normalen Mausen. Die Mehrzahl der Leukozyten ist lochkernig und stammt hauptsachlich von den ortsansassigen Fibrozyten ab. 2. Bei den nichtvorbehandelten Mausen werden nach der Salbeneinreibung die Leukozyten nur in geringer Zahl vermehrt gefunden. Dafur sind die Monozyten haufiger zu sehen. Auch diese entstehen zumeist auf Kosten der Fibrozyten.</p

Veranderungen der Zellen im subkutanen Bindegewebe der Maus bei der Injektion von Arzneimitteln. : IV. Injektion von Sulfonamidpaparaten.

Die ortliche Reizung durch die subkutan injizierten sulfonamid-praparate ist uberhaupt viel schwacher als diejenigen der Vaccine. Ihre Wirkung ist vor allem durch eine Vermehrung der Histiozyten im Subkutangewebe nicht nur am Injektionsort, sondern auch an der anderen Korperseite charakterisiert. Die Histiozyten entstehen hauptsachlich aus den ortsansassigen Fibrozyten. Es steht aber noch dahin, inwieweit die so vermehrten Histiozyten zur Heilung der Streptokokkensepsis u. a. beitragen konnen.</p

Veranderungen der Zellen im subkutanen Bindegewebe der Maus bei der Injektion von Arzneimitteln. : III. Kombinierte Anwendung von Stimin mit Ducreyn und von Moxol mit Tuberkulin.

1. Bei simultaner oder sukzedaner Injektion eines Reizkorpers, Stimins, und eines Erregervakzins, Ducreyns, in das Subkutangewebe ist die dadurch hervorgerufene Entzundung weniger heftig und klingt viel rascher ab als bei einer einfachen Ducreyninjektion. Die Vermehrung der Histiozyten ist jedoch starker. 2. Durch eine simultane und sukzedane Injektion eines Reizkorpers. Moxols, und eines Erregervakzins, Tuberkulins, wird auch die Entzundung in leichterem Grad herbeigefuhrt als durch eine einfache Tuberkulininjektion. Die Histiozyten vermehren sich auch im ersteren Fall etwas starker. 3. Die entzundungshemmende Wirkung des Stimins und Moxols beruht wohl darauf, daB die dadurch in einer mehr oder weniger groBen Zahl mobilisierten Histiozyten sich der toxischen Wirkung der Vakzine widersetzen. Die meislen Histiozyfen entstehen dabei auf Kosten der Fibrozyten.</p

Perioperative use of eicosapentaenoic acid and patency of infrainguinal vein bypass: A retrospective chart review

AbstractBackground:A significant proportion of autogenous vein grafts fail in the long term. Currently, there is no treatment to improve graft patency.Objective:This study was designed to assess the effectiveness of eicosapentaenoic acid (EPA) to prevent late failure of an autogenous vein graft and other perioperative risk factors affecting long-term patency.Methods:A retrospective chart review was performed on grafts of patients who underwent infrainguinal bypass surgery using autogenous vein grafts for peripheral arterial disease in a lower limb. Patients were stratified by the perioperative use of EPA. The EPA group was those patients who administered EPA ≥1 time within 3 months of surgery. The non-EPA group was made up of those patients who did not administer EPA within 3 months of surgery. Primary, assisted primary, and secondary patency rates of the grafts in each group were calculated by the Kaplan-Meier method and compared by the log-rank test. To evaluate the effect of other perioperative risk factors, a Cox proportional hazards analysis was performed.Results:One hundred sixty-one grafts were analyzed from 159 patients who underwent surgery between July 1991 and July 2005. The primary patency rates of the EPA and non-EPA groups were 93% and 86%, 89% and 74%, and 83% and 68% at 1, 3, and 5 years, respectively. In terms of primary patency, the EPA group was significantly better than the non-EPA group (P=0.042). There was no significant difference between the groups in either assisted primary or secondary patency. A Cox proportional hazard analysis found that the minimum graft diameter and perioperative use of EPA were significant factors for primary patency (P=0.002 and P=0.004, respectively). Graft diameter was the only significant factor for assisted primary and secondary patency (P=0.021 and P=0.003, respectively).Conclusion:Although graft diameter was the most important factor for long-term patency of infrainguinal vein bypass grafts, the perioperative use of EPA significantly improved primary patency among these subjects