26,082 research outputs found
A comparison of the expected and actual pain experienced by women during insertion of an intrauterine contraceptive device.
Objective: To compare the expected and actual pain experienced with the insertion of intrauterine contraception in women, and to determine whether either of these are related to their personal circumstances, or affected their satisfaction with the procedure. Design: A convenience sample of 89 women aged 15-50 attending a sexual health clinic for same day intrauterine contraception insertion were given a questionnaire which they completed following the procedure. The women were asked to rate their expectation of pain prior to insertion and to rate the actual pain they experienced immediately after insertion, on a scale of 1 to 10 with 10 being severe pain. Information on the women’s circumstances and their level of satisfaction with the procedure was also obtained. Results: Overall, the median actual pain experienced by women during insertion (4) was significantly lower than the expected pain median (6) (p<0.001). For those women who had not had a previous vaginal delivery, actual pain was significantly higher compared with women who had a previous vaginal delivery (median [IQR] = 6 [3.5-7.5] and 3 [1-5], p<0.001), respectively), but there was no significant difference between expected and actual pain experiences. In women who had a previous vaginal delivery, actual pain was much lower than expected (p<0.001). Neither actual nor expected pain experiences were linked to any other socio-demographic reproductive health or service use factors. Conclusion: All women had a high expectation of pain prior to IUD insertion but, for those who had a previous vaginal delivery, this was significantly greater than that actually experienced. Satisfaction levels overall were high. Counselling of women should take into account their expected pain prior to IUD insertion and consideration should be given to alternative and additional methods of pain relief in women who had not had a previous vaginal delivery
Low thrust interplanetary trajectory open loop error analysis, volume 1 Final report
Computer program for open-loop error analysis of low thrust interplanetary trajectorie
3-Body Dynamics in a (1+1) Dimensional Relativistic Self-Gravitating System
The results of our study of the motion of a three particle, self-gravitating
system in general relativistic lineal gravity is presented for an arbitrary
ratio of the particle masses. We derive a canonical expression for the
Hamiltonian of the system and discuss the numerical solution of the resulting
equations of motion. This solution is compared to the corresponding
non-relativistic and post-Newtonian approximation solutions so that the
dynamics of the fully relativistic system can be interpretted as a correction
to the one-dimensional Newtonian self-gravitating system. We find that the
structure of the phase space of each of these systems yields a large variety of
interesting dynamics that can be divided into three distinct regions: annulus,
pretzel, and chaotic; the first two being regions of quasi-periodicity while
the latter is a region of chaos. By changing the relative masses of the three
particles we find that the relative sizes of these three phase space regions
changes and that this deformation can be interpreted physically in terms of the
gravitational interactions of the particles. Furthermore, we find that many of
the interesting characteristics found in the case where all of the particles
share the same mass also appears in our more general study. We find that there
are additional regions of chaos in the unequal mass system which are not
present in the equal mass case. We compare these results to those found in
similar systems.Comment: latex, 26 pages, 17 figures, high quality figures available upon
request; typos and grammar correcte
N-body Gravity and the Schroedinger Equation
We consider the problem of the motion of bodies in a self-gravitating
system in two spacetime dimensions. We point out that this system can be mapped
onto the quantum-mechanical problem of an N-body generalization of the problem
of the H molecular ion in one dimension. The canonical gravitational
N-body formalism can be extended to include electromagnetic charges. We derive
a general algorithm for solving this problem, and show how it reduces to known
results for the 2-body and 3-body systems.Comment: 15 pages, Latex, references added, typos corrected, final version
that appears in CQ
On the treatment of threshold effects in SUSY spectrum computations
We take a critical view of the treatment of threshold effects in SUSY
spectrum computations from high-scale input. We discuss the two principal
methods of (a) renormalization at a common SUSY scale versus (b) integrating
out sparticles at their own mass scales. We point out problems in the
implementations in public spectrum codes, together with suggestions for
improvements. In concrete examples, we compare results of Isajet7.72 and
Spheno2.2.3, and present the improvements done in Isajet7.73. We also comment
on theoretical uncertainties. Last but not least, we outline how a consistent
multiscale approach may be achieved.Comment: 15 pages, 1 figur
Numerical indications of a q-generalised central limit theorem
We provide numerical indications of the -generalised central limit theorem
that has been conjectured (Tsallis 2004) in nonextensive statistical mechanics.
We focus on binary random variables correlated in a {\it scale-invariant}
way. The correlations are introduced by imposing the Leibnitz rule on a
probability set based on the so-called -product with . We show
that, in the large limit (and after appropriate centering, rescaling, and
symmetrisation), the emerging distributions are -Gaussians, i.e., , with , and
with coefficients approaching finite values . The
particular case recovers the celebrated de Moivre-Laplace theorem.Comment: Minor improvements and corrections have been introduced in the new
version. 7 pages including 4 figure
Constraints on leptogenesis from a symmetry viewpoint
It is shown that type I seesaw models based on the standard model Lagrangian
extended with three heavy Majorana right-handed fields do not have leptogenesis
in leading order, if the symmetries of mass matrices are also the residual
symmetry of the Lagrangian. In particular, flavor models that lead to a
mass-independent leptonic mixing have a vanishing leptogenesis CP asymmetry.
Based on symmetry arguments, we prove that in these models the Dirac-neutrino
Yukawa coupling combinations relevant for leptogenesis are diagonal in the
physical basis where the charged leptons and heavy Majorana neutrinos are
diagonal.Comment: 5 pages; a few comments added; final version to appear in Phys. Rev.
Chaos in an Exact Relativistic 3-body Self-Gravitating System
We consider the problem of three body motion for a relativistic
one-dimensional self-gravitating system. After describing the canonical
decomposition of the action, we find an exact expression for the 3-body
Hamiltonian, implicitly determined in terms of the four coordinate and momentum
degrees of freedom in the system. Non-relativistically these degrees of freedom
can be rewritten in terms of a single particle moving in a two-dimensional
hexagonal well. We find the exact relativistic generalization of this
potential, along with its post-Newtonian approximation. We then specialize to
the equal mass case and numerically solve the equations of motion that follow
from the Hamiltonian. Working in hexagonal-well coordinates, we obtaining
orbits in both the hexagonal and 3-body representations of the system, and plot
the Poincare sections as a function of the relativistic energy parameter . We find two broad categories of periodic and quasi-periodic motions that we
refer to as the annulus and pretzel patterns, as well as a set of chaotic
motions that appear in the region of phase-space between these two types.
Despite the high degree of non-linearity in the relativistic system, we find
that the the global structure of its phase space remains qualitatively the same
as its non-relativisitic counterpart for all values of that we could
study. However the relativistic system has a weaker symmetry and so its
Poincare section develops an asymmetric distortion that increases with
increasing . For the post-Newtonian system we find that it experiences a
KAM breakdown for : above which the near integrable regions
degenerate into chaos.Comment: latex, 65 pages, 36 figures, high-resolution figures available upon
reques
Quantum scalar field on three-dimensional (BTZ) black hole instanton: heat kernel, effective action and thermodynamics
We consider the behaviour of a quantum scalar field on three-dimensional
Euclidean backgrounds: Anti-de Sitter space, the regular BTZ black hole
instanton and the BTZ instanton with a conical singularity at the horizon. The
corresponding heat kernel and effective action are calculated explicitly for
both rotating and non-rotating holes. The quantum entropy of the BTZ black hole
is calculated by differentiating the effective action with respect to the
angular deficit at the conical singularity. The renormalization of the
UV-divergent terms in the action and entropy is considered. The structure of
the UV-finite term in the quantum entropy is of particular interest. Being
negligible for large outer horizon area it behaves logarithmically for
small . Such behaviour might be important at late stages of black hole
evaporation.Comment: 28 pages, latex, 2 figures now include
Higher Dimensional Taub-NUTs and Taub-Bolts in Einstein-Maxwell Gravity
We present a class of higher dimensional solutions to Einstein-Maxwell
equations in d-dimensions. These solutions are asymptotically locally flat,
de-Sitter, or anti-de Sitter space-times. The solutions we obtained depend on
two extra parameters other than the mass and the nut charge. These two
parameters are the electric charge, q and the electric potential at infinity,
V, which has a non-trivial contribution. We Analyze the conditions one can
impose to obtain Taub-Nut or Taub-Bolt space-times, including the
four-dimensional case. We found that in the nut case these conditions coincide
with that coming from the regularity of the one-form potential at the horizon.
Furthermore, the mass parameter for the higher dimensional solutions depends on
the nut charge and the electric charge or the potential at infinity.Comment: 11 pages, LaTe
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