5,780 research outputs found
Relative phase fluctuations of two coupled one-dimensional condensates
We study the relative phase fluctuations of two one-dimensional condensates coupled along their whole extension with a local single-atom interaction. The thermal equilibrium is defined by the competition between independent longitudinal thermally excited phase fluctuations and the coupling between the condensates which locally favors identical phase. We compute the relative phase fluctuations and their correlation length as a function of the temperature and the strength of the coupling
Population Synthesis of Radio and Gamma-ray Pulsars in the Fermi Era
We present results of our pulsar population synthesis of normal pulsars from
the Galactic disk using our previously developed computer code. On the same
footing, we use slot gap and outer gap models for gamma-ray emission from
normal pulsars to obtain statistics of radio-loud and radio-quiet gamma-ray
pulsars. From recently improved understanding of HII and star forming regions
in the Galaxy, we develop a new surface density model of the birth location of
neutron stars. We explore models of neutron star evolution with magnetic
field-decay, and with different initial period and magnetic field
distributions. We present preliminary results including simulated population
statistics that are compared with recent detections by Fermi of normal,
isolated pulsars.Comment: 4 pages, 3 figures, to appear in the proceedings of the Pulsar 2010
Conference, Italy, 10 - 15 October 201
QZ Serpentis: A Dwarf Nova with a 2-Hour Orbital Period and an Anomalously Hot, Bright Secondary Star
We present spectroscopy and time-series photometry of the dwarf nova QZ Ser.
The spectrum shows a rich absorption line spectrum of type K4 +- 2. K-type
secondary stars are generally seen in dwarf novae with orbital periods P-orb
around 6 h, but in QZ Ser the absorption radial velocities show an obvious
modulation (semi-amplitude 207(5) km/s) at P-orb = 119.752(2) min, much shorter
than typical for such a relatively warm and prominent secondary spectrum. The
H-alpha emission-line velocity is modulated at the same period and roughly
opposite phase. Time-series photometry shows flickering superposed on a
modulation with two humps per orbit, consistent with ellipsoidal variation of
the secondary's light. QZ Ser is a second example of a relatively short-period
dwarf nova with a surprisingly warm secondary. Model calculations suggest that
the secondary is strongly enhanced in helium, and had already undergone
significant nuclear evolution when mass transfer began. Several sodium
absorption features in the secondary spectrum are unusually strong, which may
indicate that the present-day surface was the site of CNO-cycle hydrogen
burning in the past.Comment: 11 pages, 3 postscript figures, 1 jpeg greyscale figure. Accepted for
publication in PAS
TERTIARY SYPHILIS (GENERAL PARALYSIS OF THE INSANE) AND BIPOLAR DISORDER; THE ROLE OF THESE TWO DISORDERS IN THE LIFE OF FAMOUS COMPOSERS
Syphilis is a complex disease, which can lead to General Paralysis of the Insane if left untreated. Before antibiotics this was the
natural progression of the disease, with many people being admitted to mental asylums with the diagnosis of GPI, and going on to die there. Diagnoses however, were difficult, as it was difficult to distinguish between GPI and other mental conditions such as bipolar disorder. We can use the works of the classical composers Beethoven, Schubert, Schumann and Smetana, who all suffered from mental illness, to gain an insight into what it is like to live with these conditions. All these are potential cases of GPI, highlighting how a sexually transmitted disease can end the life of such talented and influential people. With antibiotic resistance becoming a growing concern, it is key that we continue to recognise and treat syphilis in an appropriate manner, so as to limit the future of this disease
TERTIARY SYPHILIS (GENERAL PARALYSIS OF THE INSANE) AND BIPOLAR DISORDER; THE ROLE OF THESE TWO DISORDERS IN THE LIFE OF FAMOUS COMPOSERS
Syphilis is a complex disease, which can lead to General Paralysis of the Insane if left untreated. Before antibiotics this was the
natural progression of the disease, with many people being admitted to mental asylums with the diagnosis of GPI, and going on to die there. Diagnoses however, were difficult, as it was difficult to distinguish between GPI and other mental conditions such as bipolar disorder. We can use the works of the classical composers Beethoven, Schubert, Schumann and Smetana, who all suffered from mental illness, to gain an insight into what it is like to live with these conditions. All these are potential cases of GPI, highlighting how a sexually transmitted disease can end the life of such talented and influential people. With antibiotic resistance becoming a growing concern, it is key that we continue to recognise and treat syphilis in an appropriate manner, so as to limit the future of this disease
Validation of an automated enzyme immunoassay for interleukin-6 for routine clinical use
Serum levels of Interleukin-6 (IL-6), a proinflammatory cytokine, are increased in early stages of inflammatory diseases such as infection and sepsis. Assay systems which permit its measurement within a few hours and as a single measurement have not been reported so far. We therefore evaluated a now commercially available automated method for IL-6 measurement on the Cobas Core(R) immunological analyzer (Roche Diagnostic Systems) which enables single IL-6 measurement within about 1 hour. The automated assay correlates well with an established, manual microtiter plate assay (Biosource GmbH) which uses the same antibodies and reagents (r=0.98). Accuracy of the automated method was established by adding known amounts of IL-6 international reference preparation. Recovery of the international standard was in the range of 92-104%. The automated assay had a precision of singletons below 6% and was linear up to 2800 pg/ml. This automated assay provides a suitable, convenient and time saving method for measurement of IL-6 serum levels in the routine clinical laboratory
Pulsar twinkling and relativity
The number of pulsars with detected emission at X-ray and gamma-ray energies
has been steadily growing, showing that beams of high-energy particles are
commonly accelerated in pulsar magnetospheres, even though the location and
number of acceleration sites remain unsettled. Acceleration near the magnetic
poles, close to the polar cap surface or to higher altitudes in the slot gap
along the last open field lines, involves an electric field component due to
inertial-frame dragging. Acceleration can also take place in the outer
magnetosphere where charge depletion due to global currents causes a large
electric field along the magnetic field lines. All models require a detailed
knowledge of the open magnetosphere geometry and its relativistic distortions.
Observational trends with age, spin-down power and magnetic field as well as
population synthesis studies in the Galactic disc and the nearby Gould Belt
provide useful, however not yet conclusive, constraints on the competing
models.Comment: 9 pages, 5 figures, to be published in proceedings of the Albert
Einstein Century International Conference, Paris 200
1RXS J232953.9+062814: A Dwarf Nova with a 64-minute Orbital Period and a Conspicuous Secondary Star
We present spectroscopy and time-series photometry of the newly discovered
dwarf nova 1RXS J232953.9+062814. Photometry in superoutburst reveals a
superhump with a period of 66.06(6) minutes. The low state spectrum shows
Balmer and HeI emission on a blue continuum, and in addition shows a rich
absorption spectrum of type K4 +- 2. The absorption velocity is modulated
sinusoidally at P_orb = 64.176(5) min, with semi-amplitude K = 348(4) km/s. The
low-state light curve is double-humped at this period, and phased as expected
for ellipsoidal variations. The absorption strength does not vary appreciably
around the orbit. The orbital period is shorter than any other cataclysmic
variable save for a handful of helium-star systems and V485 Centauri (59
minutes). The secondary is much hotter than main sequence stars of similar
mass, but is well-matched by helium-enriched models, indicating that the
secondary evolved from a more massive progenitor. A preliminary calculation in
which a 1.2 solar-mass star begins mass transfer near the end of H burning
matches this system's characteristics remarkably well.Comment: accepted to Astrophysical Journal Letters; 14 pages, 3 eps figures +
1 jpg greyscale figur
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