16,977 research outputs found
Three-point Green function of massless QED in position space to lowest order
The transverse part of the three-point Green function of massless QED is
determined to the lowest order in position space. Taken together with the
evaluation of the longitudinal part in arXiv:0803.2630, this gives a relation
for QED which is analogous to the star-triangle relation. We relate our result
to conformal-invariant three-point functions.Comment: 8 page
Brane-worlds and theta-vacua
Reductions from odd to even dimensionalities ( or ), for
which the effective low-energy theory contains chiral fermions, present us with
a mismatch between ultraviolet and infrared anomalies. This applies to both
local (gauge) and global currents; here we consider the latter case. We show
that the mismatch can be explained by taking into account a change in the
spectral asymmetry of the massive modes--an odd-dimensional analog of the
phenomenon described by the Atiyah-Patodi-Singer theorem in even
dimensionalities. The result has phenomenological implications: we present a
scenario in which a QCD-like -angle relaxes to zero on a certain
(possibly, cosmological) timescale, despite the absence of any light axion-like
particle.Comment: 44 pages, 4 figure
External leg amputation in conformal invariant three-point function
Amputation of external legs is carried out explicitly for the conformal
invariant three-point function involving two spinors and one vector field. Our
results are consistent with the general result that amputing an external leg in
a conformal invariant Green function replaces a field by its conformal partner
in the Green function. A new star-triangle relation, involving two spinors and
one vector field, is derived and used for the calculation.Comment: 16 pages; last paragraph added in Sec. 10, presentation improved, to
appear in Eur. Phys. J.
A refined Razumov-Stroganov conjecture
We extend the Razumov-Stroganov conjecture relating the groundstate of the
O(1) spin chain to alternating sign matrices, by relating the groundstate of
the monodromy matrix of the O(1) model to the so-called refined alternating
sign matrices, i.e. with prescribed configuration of their first row, as well
as to refined fully-packed loop configurations on a square grid, keeping track
both of the loop connectivity and of the configuration of their top row. We
also conjecture a direct relation between this groundstate and refined totally
symmetric self-complementary plane partitions, namely, in their formulation as
sets of non-intersecting lattice paths, with prescribed last steps of all
paths.Comment: 20 pages, 4 figures, uses epsf and harvmac macros a few typos
correcte
Analysis of Information and Communication Technology Literacy Capabilities to the High School Physics Teacher in Merauke
A physics teacher needs information and Communication Technology (ICT) literacy skills in teaching and learning in the classroom. This study aims to analyze the ICT literacy skills of high school physics teachers in Merauke city. This type of research is descriptive quantitative research. Respondents involved in this study were 19 high school physics teachers in Merauke City (Merauke District). The instrument used to collect data was an ICT literacy ability questionnaire developed by researchers totaling 40 statements. The research data were processed using descriptive statistical analysis techniques by determining the percentage of respondents' responses. The analysis showed that the average rate of ICT literacy skills in high school physics teachers was 87%. This means that in general, the ICT literacy skills of high school physics teachers in Merauke City are in the "excellent" category
Evidence for a Finite Temperature Insulator
In superconductors the zero-resistance current-flow is protected from
dissipation at finite temperatures (T) by virtue of the short-circuit condition
maintained by the electrons that remain in the condensed state. The recently
suggested finite-T insulator and the "superinsulating" phase are different
because any residual mechanism of conduction will eventually become dominant as
the finite-T insulator sets-in. If the residual conduction is small it may be
possible to observe the transition to these intriguing states. We show that the
conductivity of the high magnetic-field insulator terminating superconductivity
in amorphous indium-oxide exhibits an abrupt drop, and seem to approach a zero
conductance at T<0.04 K. We discuss our results in the light of theories that
lead to a finite-T insulator
Fertility and early pregnancy outcomes after treatment for cervical intraepithelial neoplasia: systematic review and meta-analysis
OBJECTIVE:
To determine the impact of cervical excision for cervical intraepithelial neoplasia on fertility and early pregnancy outcomes.
DESIGN:
Systematic review and meta-analysis of cohort studies.
DATA SOURCES:
Medline and Embase.
ELIGIBILITY CRITERIA:
Studies assessing fertility and early pregnancy outcomes in women with a history of treatment for cervical intraepithelial neoplasia versus untreated women. We classified the included studies according to treatment type and fertility or early pregnancy endpoint.
ANALYSIS:
Pooled relative risks and 95% confidence intervals using a random effect model, and interstudy heterogeneity with I(2) statistics.
RESULTS:
15 studies fulfilled the inclusion criteria and were included. The meta-analysis did not provide any evidence that treatment for cervical intraepithelial neoplasia adversely affected the chances of conception. The overall pregnancy rate was higher for treated women than for untreated women (four studies; 43% v 38%, pooled relative risk 1.29, 95% confidence interval 1.02 to 1.64), although the heterogeneity between studies was high (P<0.0001). Pregnancy rates did not differ between women with an intention to conceive (two studies; 88% v 95%, 0.93, 0.80 to 1.08) and the number requiring more than 12 months to conceive (three studies, 15% v 9%, 1.45, 0.89 to 2.37). Although the rates for total miscarriages (10 studies; 4.6% v 2.8%, 1.04, 0.90 to 1.21) and miscarriage in the first trimester (four studies; 9.8% v 8.4%, 1.16, 0.80 to 1.69) was similar for treated and untreated women, cervical treatment was associated with a significantly increased risk of miscarriage in the second trimester. The rate was higher for treated women than for untreated women (eight studies; 1.6% v 0.4%, 16,558 women; 2.60, 1.45 to 4.67). The number of ectopic pregnancies (1.6% v 0.8%; 1.89, 1.50 to 2.39) and terminations (12.2% v 7.4%; 1.71, 1.31 to 2.22) was also higher for treated women.
CONCLUSION:
There is no evidence suggesting that treatment for cervical intraepithelial neoplasia adversely affects fertility, although treatment was associated with a significantly increased risk of miscarriages in the second trimester. Research should explore mechanisms that may explain this increase in risk and stratify the impact that treatment may have on fertility and early pregnancy outcomes by the size of excision and treatment method used
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