8,743 research outputs found
Yangian Symmetry, S-Matrices and Bethe Ansatz for the AdS5 x S5 Superstring
We discuss the relation between the recently derived bound state S-matrices
for the AdS5 x S5 superstring and Yangian symmetry. We will study the relation
between this Yangian symmetry and the Bethe ansatz. In particular we can use it
to derive the Bethe equations for bound states.Comment: Proceedings of the work presented at the 4-th EU RTN Workshop in
Varna, Bulgari
Bound States, Yangian Symmetry and Classical r-matrix for the AdS5 x S5 Superstring
We show that the recently found S-matrices describing the scattering of
two-particle bound states of the light-cone string sigma model on AdS5 x S5 are
compatible with Yangian symmetry. In case the invariance with respect to the
centrally extended su(2|2) algebra is not sufficient to fully specify the
scattering matrix, the requirement of Yangian symmetry provides an alternative
to the Yang-Baxter equation and leads to a complete, up to an overall phase,
determination of the S-matrix. We then compare the semi-classical limit of the
bound state S-matrices with the universal classical r-matrix by Beisert and
Spill evaluated in the corresponding bound state representations and find
perfect agreement.Comment: V3: Published version, reference adde
Bound States of the q-Deformed AdS5 x S5 Superstring S-matrix
The investigation of the q deformation of the S-matrix for excitations on the
string world sheet in AdS5 x S5 is continued. We argue that due to the lack of
Lorentz invariance the situation is more subtle than in a relativistic theory
in that the nature of bound states depends on their momentum. At low enough
momentum |p|<E the bound states transform in the anti-symmetric representation
of the super-algebra symmetry and become the solitons of the Pohlmeyer reduced
theory in the relativistic limit. At a critical momentum |p|=E they become
marginally unstable, and at higher momenta the stable bound states are in the
symmetric representation and become the familiar magnons in the string limit as
q->1. This subtlety fixes a problem involving the consistency of crossing
symmetry with the relativistic limit found in earlier work. With mirror
kinematics, obtained after a double Wick rotation, the bound state structure is
simpler and there are no marginally unstable bound states.Comment: 25 page
Nationwide population-based cohort study of uterine rupture in Belgium : results from the Belgian Obstetric Surveillance System
Objectives: We aimed to assess the prevalence of uterine rupture in Belgium and to evaluate risk factors, management and outcomes for mother and child.
Design: Nationwide population-based prospective cohort study.
Setting: Emergency obstetric care. Participation of 97% of maternity units covering 98.6% of the deliveries in Belgium.
Participants: All women with uterine rupture in Belgium between January 2012 and December 2013. 8 women were excluded because data collection forms were not returned.
Results: Data on 90 cases of confirmed uterine rupture were obtained, of which 73 had a previous Caesarean section (CS), representing an estimated prevalence of 3.6 (95% CI 2.9 to 4.4) per 10000 deliveries overall and of 27 (95% CI 21 to 33) and 0.7 (95% CI 0.4 to 1.2) per 10000 deliveries in women with and without previous CS, respectively. Rupture occurred during trial of labour after caesarean section (TOLAC) in 57 women (81.4%, 95% CI 68% to 88%), with a high rate of augmented (38.5%) and induced (29.8%) labour. All patients who underwent induction of labour had an unfavourable cervix at start of induction (Bishop Score 7 in 100%). Other uterine surgery was reported in the history of 22 cases (24%, 95% CI 17% to 34%), including 1 case of myomectomy, 3 cases of salpingectomy and 2 cases of hysteroscopic resection of a uterine septum. 14 cases ruptured in the absence of labour (15.6%, 95% CI 9.5% to 24.7%). No mothers died; 8 required hysterectomy (8.9%, 95% CI 4.6% to 16.6%). There were 10 perinatal deaths (perinatal mortality rate 117/1000 births, 95% CI 60 to 203) and perinatal asphyxia was observed in 29 infants (34.5%, 95% CI 25.2% to 45.1%).
Conclusions: The prevalence of uterine rupture in Belgium is similar to that in other Western countries. There is scope for improvement through the implementation of nationally adopted guidelines on TOLAC, to prevent use of unsafe procedures, and thereby reduce avoidable morbidity and mortality
The Bethe Ansatz for AdS5 x S5 Bound States
We reformulate the nested coordinate Bethe ansatz in terms of coproducts of
Yangian symmetry generators. This allows us to derive the nested Bethe
equations for the bound state string S-matrices. We find that they coincide
with the Bethe equations obtained from a fusion procedure. The bound state
number dependence in the Bethe equations appears through the parameters x^{\pm}
and the dressing phase only.Comment: typos correcte
Biolegality: How Biology and Law Redefine Sociality
As an empirical concept, biolegality emerged at the height of biotechnological advances in Euro-American societies when rapid changes in the life sciences (including molecular biology, immunology, and the neurosciences) and their attendant techniques (including reproductive technologies and gene editing) started to challenge ethical norms, legal decisions, and legal forms. As a theoretical concept, biolegality deepens the Foucauldian notion of biopolitics with an operation of legality that emphasizes how biology and its attendant technologies alter legal form, knowledge, practice, and experience. These empirical and theoretical developments affect how we understand sociality. While public discourse remains preoccupied with the call for more regulation mdash thereby underscoring law's lag in its dealings with technology mdash the social science scholarship describes instead how bioscience and biotechnology are fragmenting and rearranging legal knowledge about property, personhood, parenthood, and collective identity. As it opens broader anthropological debates around exchange, self, kinship, and community, the study of biolegality brings a novel currency to the discipline, addressing how biology and law inform new ways of relating and knowing
The Bound State S-Matrix for AdS5 x S5 Superstring
We determine the S-matrix that describes scattering of arbitrary bound states
in the light-cone string theory in AdS5 x S5. The corresponding construction
relies on the Yangian symmetry and the superspace formalism for the bound state
representations. The basic analytic structure supporting the S-matrix entries
turns out to be the hypergeometric function 4F3. We show that for particular
bound state numbers it reproduces all the scattering matrices previously
obtained in the literature. Our findings should be relevant for the TBA and
Luescher approaches to the finite-size spectral problem. They also shed some
light on the construction of the universal R-matrix for the centrally-extended
psu(2|2) superalgebra.Comment: 37 pages, 2 figures, v2: typos correcte
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