2,887 research outputs found
A Review of Characteristics and Treatments of the Avoidant Personality Disorder. Could the DBT be an Option?
Magnetic fields generated by r-modes in accreting millisecond pulsars
In millisecond pulsars the existence of the Coriolis force allows the
development of the so-called Rossby oscillations (r-modes) which are know to be
unstable to emission of gravitational waves. These instabilities are mainly
damped by the viscosity of the star or by the existence of a strong magnetic
field. A fraction of the observed millisecond pulsars are known to be inside
Low Mass X-ray Binaries (LMXBs), systems in which a neutron star (or a black
hole) is accreting from a donor whose mass is smaller than 1 . Here we
show that the r-mode instabilities can generate strong toroidal magnetic fields
by inducing differential rotation. In this way we also provide an alternative
scenario for the origin of the magnetars.Comment: 6 pages, 3 figures, Proceedings conference "Theoretical Nuclear
Physics", Cortona October 200
Generation of strong magnetic fields by r-modes in millisecond accreting neutron stars: induced deformations and gravitational wave emission
Differential rotation induced by the r-mode instability can generate very
strong toroidal fields in the core of accreting, millisecond spinning neutron
stars. We introduce explicitly the magnetic damping term in the evolution
equations of the r-modes and solve them numerically in the Newtonian limit, to
follow the development and growth of the internal magnetic field. We show that
the strength of the latter can reach large values, G, in the
core of the fastest accreting neutron stars. This is strong enough to induce a
significant quadrupole moment of the neutron star mass distribution,
corresponding to an ellipticity |\epsilon_B}| \sim 10^{-8}. If the symmetry
axis of the induced magnetic field is not aligned with the spin axis, the
neutron star radiates gravitational waves. We suggest that this mechanism may
explain the upper limit of the spin frequencies observed in accreting neutron
stars in Low Mass X-Ray Binaries. We discuss the relevance of our results for
the search of gravitational waves.Comment: 11 pages, 8 figure
Magnetars as Highly Magnetized Quark Stars: an analytical treatment
We present an analytical model of a magnetar as a high density magnetized
quark bag. The effect of strong magnetic fields (B > 5 x 10^{16} G) in the
equation of state is considered. An analytic expression for the Mass-Radius
relationship is found from the energy variational principle in general
relativity. Our results are compared with observational evidences of possible
quark and/or hybrid stars.Comment: 15 pages, 1 figure/Comments added and two references removed.
Accepted for publication in Astrophysical Journa
Magnetic Evolution and Temperature Variation in a Coronal Hole
We have explored the magnetic flux evolution and temperature variation in a
coronal-hole region, using Big Bear Solar Observatory (BBSO) deep magnetograms
and {\it SOHO}/EIT images observed from 2005 October 10 to 14. For comparison,
we also investigated a neighboring quiet region of the Sun. The coronal hole
evolved from its mature stage to its disappearance during the observing period.
We have obtained the following results: (1) When the coronal hole was well
developed on October 10, about 60 % of the magnetic flux was positive. The EUV
brightness was 420 counts pixel, and the coronal temperature, estimated
from the line ratio of the EIT 195 {\AA} and 171 {\AA} images, was 1.07 MK. (2)
On October 14, when the coronal hole had almost disappeared, 51 % of the
magnetic flux was positive, the EUV radiance was 530 counts pixel, and
the temperature was 1.10 MK. (3) In the neighboring quiet region, the fraction
of positive flux varied between 0.49 and 0.47. The EUV brightness displayed an
irregular variation, with a mean value of 870 counts pixel. The
temperature was almost constant at 1.11 MK during the five-day observation. Our
results demonstrate that in a coronal hole less imbalance of the magnetic flux
in opposite polarities leads to stronger EUV brightness and higher coronal
temperatures
No association of a set of candidate genes on haloperidol side effects.
We previously investigated a sample of patients during an active phase of psychosis in the search for genetic predictors of haloperidol induced side effects. In the present work we extend the genetic association analysis to a wider panel of genetic variations, including 508 variations located in 96 genes. The original sample included 96 patients. An independent group of 357 patients from the CATIE study served as a replication sample. Outcomes in the investigation sample were the variation through time of: 1) the ESRS and UKU total scores 2) ESRS and UKU subscales (neurologic and psychic were included) related to tremors and 3) ESRS and UKU subscales that do not relate to tremors. Outcome in the replication sample was the presence vs absence of motoric side effects from baseline to visit 1 (~ one month of treatment) as assessed by the AIMS scale test. Rs2242480 located in the CYP3A4 was associated with a different distribution of the UKU neurologic scores through time (permutated p = 0.047) along with a trend for a different haloperidol plasma levels (lower in CC subjects). This finding was not replicated in the CATIE sample. In conclusion, we did not find conclusive evidence for a major association between the investigated variations and haloperidol induced motoric side effects
Equation of state at high densities and modern compact star observations
Recently, observations of compact stars have provided new data of high
accuracy which put strong constraints on the high-density behaviour of the
equation of state of strongly interacting matter otherwise not accessible in
terrestrial laboratories. The evidence for neutron stars with high mass (M =2.1
+/- 0.2 M_sun for PSR J0751+1807) and large radii (R > 12 km for RX J1856-3754)
rules out soft equations of state and has provoked a debate whether the
occurence of quark matter in compact stars can be excluded as well. In this
contribution it is shown that modern quantum field theoretical approaches to
quark matter including color superconductivity and a vector meanfield allow a
microscopic description of hybrid stars which fulfill the new, strong
constraints. The deconfinement transition in the resulting stiff hybrid
equation of state is weakly first order so that signals of it have to be
expected due to specific changes in transport properties governing the
rotational and cooling evolution caused by the color superconductivity of quark
matter. A similar conclusion holds for the investigation of quark deconfinement
in future generations of nucleus-nucleus collision experiments at low
temperatures and high baryon densities such as CBM @ FAIR.Comment: 6 pages, 2 figures, accepted for publication in J. Phys. G. (Special
Issue
Effectiveness evaluation of STOL transport operations
A short-takeoff and landing (STOL) systems simulation model has been developed and implemented in a computer code (known as STOL OPS) which permits evaluation of the operation of a STOL aircraft and its avionics in a commercial airline operating environment. STOL OPS concentrated on the avionics functions of navigation, guidance, control, communication, hazard aviodance, and systems management. External world factors influencing the operation of the STOL aircraft include each airport and its geometry, air traffic at each airport, air traffic control equipment and procedures, weather (including winds and visibility), and the flight path between each airport served by the route. The development of the STOL OPS program provides NASA a set of computer programs which can be used for detailed analysis of a STOL aircraft and its avionics and permit establishment of system requirements as a function of airline mission performance goals
A dynamical, confining model and hot quark stars
We explore the consequences of an equation of state (EOS) obtained in a
confining Dyson-Schwinger equation model of QCD for the structure and stability
of nonstrange quark stars at finite-T, and compare the results with those
obtained using a bag-model EOS. Both models support a temperature profile that
varies over the star's volume and the consequences of this are model
independent. However, in our model the analogue of the bag pressure is
(T,mu)-dependent, which is not the case in the bag model. This is a significant
qualitative difference and comparing the results effects a primary goal of
elucidating the sensitivity of quark star properties to the form of the EOS.Comment: 13 pages, 5 figures, epsfig.sty, elsart.sty. Shortened version to
appear in Phys. Lett. B, qualitatively unmodifie
- …