The Orbital Period of the Be/Neutron Star Binary RX J0812.4-3114

We present the results of Rossi X-ray Timing Explorer observations of the Be star X-ray binary system RX J0812.4-3114. A light curve obtained with the RXTE All-Sky Monitor shows that the source is currently in an active state with outbursts occurring at approximately 80 day intervals. The source underwent a transition from an inactive state to this regular outburst state early in 1998. An observation of RX J0812.4-3114 was obtained with the RXTE Proportional Counter Array close to the time of a predicted maximum in March 1999 and strong pulsations were detected at a period of 31.88 seconds. This confirms the result of an earlier PCA observation by Reig & Roche which was serendipitously also obtained near the predicted maximum flux of the 80 day period and also near the start of the current active state. We interpret the periodicity in the ASM light curve as indicating the orbital period of RX J0812.4-3114 with outbursts occurring around periastron passage

Historical changes in the phenology of British Odonata are related to climate

Responses of biota to climate change take a number of forms including distributional shifts, behavioural changes and life history changes. This study examined an extensive set of biological records to investigate changes in the timing of life history transitions (specifically emergence) in British Odonata between 1960 and 2004. The results show that there has been a significant, consistent advance in phenology in the taxon as a whole over the period of warming that is mediated by life history traits. British odonates significantly advanced the leading edge (first quartile date) of the flight period by a mean of 1.51 ±0.060 (SEM, n=17) days per decade or 3.08±1.16 (SEM, n=17) days per degree rise in temperature when phylogeny is controlled for. This study represents the first review of changes in odonate phenology in relation to climate change. The results suggest that the damped temperature oscillations experienced by aquatic organisms compared with terrestrial organisms are sufficient to evoke phenological responses similar to those of purely terrestrial taxa

4U2206+54 - an Unusual High Mass X-ray Binary with a 9.6 Day Orbital Period but No Strong Pulsations

Rossi X-ray Timing Explorer All-Sky Monitor observations of the X-ray source 4U2206+54, previously proposed to be a Be star system, show the X-ray flux to be modulated with a period of approximately 9.6 days. If the modulation is due to orbital variability then this would be one of the shortest orbital periods known for a Be star X-ray source. However, the X-ray luminosity is relatively modest whereas a high luminosity would be predicted if the system contains a neutron star accreting from the denser inner regions of a Be star envelope. Although a 392s pulse period was previously reported from EXOSAT observations, a reexamination of the EXOSAT light curves does not show this or any other periodicity. An analysis of archival RXTE Proportional Counter Array observations also fails to show any X-ray pulsations. We consider possible models that may explain the properties of this source including a neutron star with accretion halted at the magnetosphere and an accreting white dwarf.Comment: Accepted for publication in the Astrophysical Journa

Spin period change and the magnetic fields of neutron stars in Be X-ray binaries in the Small Magellanic Cloud

We report on the long-term average spin period, rate of change of spin period and X-ray luminosity during outbursts for 42 Be X-ray binary systems in the Small Magellanic Cloud. We also collect and calculate parameters of each system and use these data to determine that all systems contain a neutron star which is accreting via a disc, rather than a wind, and that if these neutron stars are near spin equilibrium, then over half of them, including all with spin periods over about 100 s, have magnetic fields over the quantum critical level of 4.4x10^13 G. If these neutron stars are not close to spin equilibrium, then their magnetic fields are inferred to be much lower, of the order of 10^6-10^10 G, comparable to the fields of neutron stars in low-mass X-ray binaries. Both results are unexpected and have implications for the rate of magnetic field decay and the isolated neutron star population.Comment: 22 pages, 50 figures; to appear in MNRA

Full-mouth disinfection versus one-stage full-mouth mechanical debridement in the management of adult periodontitis - clinical results

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Full-mouth disinfection versus one-stage mechanical debridement in the management of adult periodontitis - microbiological morphotype monitoring

published_or_final_versio

RXTE Observations of the Be star X-ray Transient X0726-260 (4U0728-25) - Orbital and Pulse Periods

Rossi X-ray Timing Explorer (RXTE) All Sky Monitor observations of the transient Be star X-ray source X0726-260 suggest a 34.5 day period. This is apparently confirmed by a serendipitous RXTE Proportional Counter Array (PCA) slew detection of the source on 1997 May 5, near the time of a predicted flux maximum. A subsequent 5000 second pointed observation of X0726-260 with the RXTE PCA detector was carried out on 1997 June 7, when X0726-260 was predicted to be bright again, and this revealed pulsations at a period of 103.2 seconds. If the 34.5 day period is orbital, then the pulse period is surprisingly long compared to that predicted by the correlation between orbital period and spin period observed for other Be/neutron star systems. A possible similarity with GROJ2058+42 is briefly discussed.Comment: 7 pages LateX, 7 figures. To be published in Astrophysical Journal Letter

Discovery of a 7 Second Anomalous X-ray Pulsar in the Distant Milky Way

We report the serendipitous discovery of a 7-s X-ray pulsar using data acquired with the Advanced Satellite for Cosmology and Astrophysics. The pulsar is detected as an unresolved source located towards a region of the Galactic plane (l,b ~ 29.5, 0.08) that coincides with an overdensity of star-formation tracers. The signal suffers tremendous foreground absorption, equivalent to N_H ~ 10E23 cm^-2; the absorption correlates well with a line-of-sight that is tangential to the inner spiral arms and the 4-kpc molecular ring. The pulsar is not associated with any known supernova remnants or other cataloged objects in that direction. The near sinusoidal pulse (period P ~ 6.9712) is modulated at 35% pulsed amplitude, and the steep spectrum is characteristic of hot black-body emission with temperature kT ~ 0.65 keV. We characterize the source as an anomalous X-ray pulsar (AXP).Comment: 8 pages, latex, 4 figures, Accepted for publication in New Astronom

The Distance of the Gamma-ray Binary 1FGL J1018.6-5856

The recently discovered gamma-ray binary 1FGL J1018.6-5856 has a proposed optical/near-infrared (OIR) counterpart 2MASS 10185560-5856459. We present Stromgren photometry of this star to investigate its photometric variability and measure the reddening and distance to the system. We find that the gamma-ray binary has E(B-V) = 1.34 +/- 0.04 and d = 5.4^+4.6_-2.1 kpc. While E(B-V) is consistent with X-ray observations of the neutral hydrogen column density, the distance is somewhat closer than some previous authors have suggested.Comment: Accepted to PAS