7,020 research outputs found
Space VLBI Observations Show in the Quasar NRAO 530
We present here space-based VLBI observations with VSOP and a southern
hemisphere ground array of the gamma-ray blazar NRAO 530 at 1.6 GHz and 5 GHz.
The brightness temperature of the core at 1.6 GHz is K. The
size is near the minimum observable value in the direction of NRAO~530 due to
interstellar scattering. The 5 GHz data show a single component with a
brightness temperature of K, significantly in excess of
the inverse Compton limit and of the equipartition brightness temperature limit
(Readhead 1994). This is strong evidence for relativistic motion in a jet
requiring model-dependent Doppler boosting factors in the range 6 to 60. We
show that a simple homogeneous sphere probably does not model the emission
region accurately. We favor instead an inhomogeneous jet model with a Doppler
boosting factor of 15.Comment: 12 pages, 2 figures. Accepted for publication in ApJ Letter
New Pulsars from an Arecibo Drift Scan Search
We report the discovery of pulsars J0030+0451, J0711+0931, and J1313+0931
that were found in a search of 470 square degrees at 430 MHz using the 305m
Arecibo telescope. The search has an estimated sensitivity for long period, low
dispersion measure, low zenith angle, and high Galactic latitude pulsars of ~1
mJy, comparable to previous Arecibo searches. Spin and astrometric parameters
for the three pulsars are presented along with polarimetry at 430 MHz. PSR
J0030+0451, a nearby pulsar with a period of 4.8 ms, belongs to the less common
category of isolated millisecond pulsars. We have measured significant
polarization in PSR J0030+0451 over more than 50% of the period, and use these
data for a detailed discussion of its magnetospheric geometry. Scintillation
observations of PSR J0030+0451 provide an estimate of the plasma turbulence
level along the line of sight through the local interstellar medium.Comment: 21 pages, 4 figures, Accepted for Publication in Ap
PSR J0609+2130: A disrupted binary pulsar?
We report the discovery and initial timing observations of a 55.7-ms pulsar,
J0609+2130, found during a 430-MHz drift-scan survey with the Arecibo radio
telescope. With a spin-down rate of s s and an
inferred surface dipole magnetic field of only G,
J0609+2130 has very similar spin parameters to the isolated pulsar J2235+1506
found by Camilo, Nice & Taylor (1993). While the origin of these weakly
magnetized isolated neutron stars is not fully understood, one intriguing
possibility is that they are the remains of high-mass X-ray binary systems
which were disrupted by the supernova explosion of the secondary star.Comment: 5 pages, 2 figures, accepted for publication in MNRAS (letters
Gender differences in the implementation of cardiovascular prevention measures after an acute coronary event
Objective To compare gender-related lifestyle changes and risk factor management after hospitalisation for a coronary event or revascularisation intervention in Europe.
Method The EUROASPIRE III survey was carried out in 22 European countries in 2006-2007. Consecutive patients having had a coronary event or revascularisation before the age of 80 were identified. A total of 8966 patients (25.3% women) were interviewed and underwent clinical and biochemical tests at least 6 months after hospital admission. Trends in cardiovascular risk management were assessed on the basis of the 1994-1995, 1999-2000 and 2006-2007 EUROASPIRE surveys.
Results Female survey participants were generally older and had a lower educational level than male participants (p<0.0001). The prevalences of obesity (p<0.0001), high blood pressure (BP) (p=0.001), elevated low-density lipoprotein (LDL)-cholesterol (p<0.0001) and diabetes (p<0.0001) were significantly higher in women than in men, whereas current smoking (p<0.0001) was significantly more common in men. The use of antihypertensive and antidiabetic drugs (but not that of other drugs) was more common in women than in men. However, BP (p<0.0001), LDL-cholesterol (p<0.0001) and HbA1c (p<0.0001) targets were less often achieved in women than in men. Between 1994 and 2007, cholesterol control improved less in women than in men (interaction: p=0.009), whereas trends in BP control (p=0.32) and glycaemia (p=0.36) were similar for both genders.
Conclusion The EUROASPIRE III results show that despite similarities in medication exposure, women are less likely than men to achieve BP, LDL-cholesterol and HbA1c targets after a coronary event. This gap did not appear to narrow between 1994 and 2007
- …
