3,797 research outputs found
The AdS_5xS^5 superstring worldsheet S-matrix and crossing symmetry
An S-matrix satisying the Yang-Baxter equation with symmetries relevant to
the AdS_5xS^5 superstring has recently been determined up to an unknown scalar
factor. Such scalar factors are typically fixed using crossing relations,
however due to the lack of conventional relativistic invariance, in this case
its determination remained an open problem.
In this paper we propose an algebraic way to implement crossing relations for
the AdS_5xS^5 superstring worldsheet S-matrix. We base our construction on a
Hopf-algebraic formulation of crossing in terms of the antipode and introduce
generalized rapidities living on the universal cover of the parameter space
which is constructed through an auxillary, coupling constant dependent,
elliptic curve. We determine the crossing transformation and write functional
equations for the scalar factor of the S-matrix in the generalized rapidity
plane.Comment: 27 pages, no figures; v2: sign typo fixed in (24), everything else
unchange
Canonical transformations in three-dimensional phase space
Canonical transformation in a three-dimensional phase space endowed with
Nambu bracket is discussed in a general framework. Definition of the canonical
transformations is constructed as based on canonoid transformations. It is
shown that generating functions, transformed Hamilton functions and the
transformation itself for given generating functions can be determined by
solving Pfaffian differential equations corresponding to that quantities. Types
of the generating functions are introduced and all of them is listed.
Infinitesimal canonical transformations are also discussed. Finally, we show
that decomposition of canonical transformations is also possible in
three-dimensional phase space as in the usual two-dimensional one.Comment: 19 pages, 1 table, no figures. Accepted for publication in Int. J.
Mod. Phys.
A peptide with N-terminal histidine and C-terminal isoleucine amide (PHI) and vasoactive intestinal peptide (VIP) are copackaged in myenteric neurones of the guinea pig ileum.
When cytoplasmic extracts of the myenteric plexus of guinea pig ileum are submitted to centrifugal density gradient separation in a zonal rotor, conditions which separate storage particles containing substance P, somatostatin and VIP from each other, PHI copurifies with VIP. The two immunoreactivities cannot be separated by particle exclusion chromatography, which depends on size rather than density. It is concluded that the posttranslational cleavage of the propeptide or precursor to PHI and VIP occurs after packaging into these storage particles
Some addition formulae for Abelian functions for elliptic and hyperelliptic curves of cyclotomic type
We discuss a family of multi-term addition formulae for Weierstrass functions
on specialized curves of genus one and two with many automorphisms. In the
genus one case we find new addition formulae for the equianharmonic and
lemniscate cases, and in genus two we find some new addition formulae for a
number of curves, including the Burnside curve.Comment: 19 pages. We have extended the Introduction, corrected some typos and
tidied up some proofs, and inserted extra material on genus 3 curve
The eVALuate study: two parallel randomised trials, one comparing laparoscopic with abdominal hysterectomy, the other comparing laparoscopic with vaginal hysterectomy
OBJECTIVE: To compare the effects of laparoscopic hysterectomy
and abdominal hysterectomy in the abdominal trial, and
laparoscopic hysterectomy and vaginal hysterectomy in the
vaginal trial.
DESIGN: Two parallel, multicentre, randomised trials.
Setting 28 UK centres and two South African centres.
Participants 1380 women were recruited; 1346 had surgery;
937 were followed up at one year.
PRIMARY OUTCOME: outcome Rate of major complications.
RESULTS: In the abdominal trial laparoscopic hysterectomy was
associated with a higher rate of major complications than
abdominal hysterectomy (11.1% v 6.2%, P = 0.02; difference
4.9%, 95% confidence interval 0.9% to 9.1%) and the number
needed to treat to harm was 20. Laparoscopic hysterectomy
also took longer to perform (84 minutes v 50 minutes) but was
less painful (visual analogue scale 3.51 v 3.88, P = 0.01) and
resulted in a shorter stay in hospital after the operation (3 days
v 4 days). Six weeks after the operation, laparoscopic
hysterectomy was associated with less pain and better quality of
life than abdominal hysterectomy (SF-12, body image scale, and
sexual activity questionnaires).
In the vaginal trial we found no evidence of a difference in
major complication rates between laparoscopic hysterectomy
and vaginal hysterectomy (9.8% v 9.5%, P = 0.92; difference
0.3%, − 5.2% to 5.8%), and the number needed to treat to harm
was 333.We found no evidence of other differences between
laparoscopic hysterectomy and vaginal hysterectomy except
that laparoscopic hysterectomy took longer to perform (72
minutes v 39 minutes) and was associated with a higher rate of
detecting unexpected pathology (16.4% v 4.8%, P = < 0.01).
However, this trial was underpowered.
CONCLUSIONS: Laparoscopic hysterectomy was associated with a
significantly higher rate of major complications than abdominal
hysterectomy. It also took longer to perform but was associated
with less pain, quicker recovery, and better short term quality of
life. The trial comparing vaginal hysterectomy with laparoscopic
hysterectomy was underpowered and is inconclusive on the rate
of major complications; however, vaginal hysterectomy took less
time
Free Energy of the Eight Vertex Model with an Odd Number of Lattice Sites
We calculate the bulk contribution for the doubly degenerated largest
eigenvalue of the transfer matrix of the eight vertex model with an odd number
of lattice sites N in the disordered regime using the generic equation for
roots proposed by Fabricius and McCoy. We show as expected that in the
thermodynamic limit the result coincides with the one in the N even case.Comment: 11 pages LaTeX New introduction, Method change
Differential constraints and exact solutions of nonlinear diffusion equations
The differential constraints are applied to obtain explicit solutions of
nonlinear diffusion equations. Certain linear determining equations with
parameters are used to find such differential constraints. They generalize the
determining equations used in the search for classical Lie symmetries
Past and future blurring at fundamental length scale
We obtain the -deformed versions of the retarded and advanced Green
functions and show that their causality properties are blurred in a time
interval of the order of a length parameter . The functions also
indicate a smearing of the light cone. These results favor the interpretation
of as a fundamental length scale below which the concept of a point in
spacetime should be substituted by the concept of a fuzzy region of radius ,
as proposed long ago by Heisenberg.Comment: Essentially, this is the version published in the Phys. Rev. Lett.
105, 211601 (2010). It has 4 pages and contains 2 figure
Inverse problem and Bertrand's theorem
The Bertrand's theorem can be formulated as the solution of an inverse
problem for a classical unidimensional motion. We show that the solutions of
these problems, if restricted to a given class, can be obtained by solving a
numerical equation. This permit a particulary compact and elegant proof of
Bertrand's theorem.Comment: 11 pages, 3 figure
Exact and simple results for the XYZ and strongly interacting fermion chains
We conjecture exact and simple formulas for physical quantities in two
quantum chains. A classic result of this type is Onsager, Kaufman and Yang's
formula for the spontaneous magnetization in the Ising model, subsequently
generalized to the chiral Potts models. We conjecture that analogous results
occur in the XYZ chain when the couplings obey J_xJ_y + J_yJ_z + J_x J_z=0, and
in a related fermion chain with strong interactions and supersymmetry. We find
exact formulas for the magnetization and gap in the former, and the staggered
density in the latter, by exploiting the fact that certain quantities are
independent of finite-size effects
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