1,796 research outputs found
Unitary Positive-Energy Representations of Scalar Bilocal Quantum Fields
The superselection sectors of two classes of scalar bilocal quantum fields in
D>=4 dimensions are explicitly determined by working out the constraints
imposed by unitarity. The resulting classification in terms of the dual of the
respective gauge groups U(N) and O(N) confirms the expectations based on
general results obtained in the framework of local nets in algebraic quantum
field theory, but the approach using standard Lie algebra methods rather than
abstract duality theory is complementary. The result indicates that one does
not lose interesting models if one postulates the absence of scalar fields of
dimension D-2 in models with global conformal invariance. Another remarkable
outcome is the observation that, with an appropriate choice of the Hamiltonian,
a Lie algebra embedded into the associative algebra of observables completely
fixes the representation theory.Comment: 27 pages, v3: result improved by eliminating redundant assumptio
Correlation Functions of Conserved Currents in Four Dimensional Conformal Field Theory
We derive a generating function for all the 3-point functions of higher spin
conserved currents in four dimensional conformal field theory. The resulting
expressions have a rather surprising factorized form which suggest that they
can all be realized by currents built from free massless fields of arbitrary
(half-)integer spin s. This property is however not necessarily true also for
the higher-point functions. As an illustration we analyze the general 4-point
function of conserved abelian U(1) currents of scale dimension equal to three
and find that apart from the two free field realizations there is a unique
possible function which may correspond to an interacting theory. Although this
function passes several non-trivial consistency tests, it remains an open
challenging problem whether it can be actually realized in an interacting CFT.Comment: 20 pages, LaTeX, references adde
AGE MORPHOMETRIC CHARACTERISTIQUE OF MICROPINOCYTOTIC VESICULATION IN VASCULAR ENDOTHELIAL CELLS (VEC)
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Private Decayed Sum Estimation under Continual Observation
In monitoring applications, recent data is more important than distant data.
How does this affect privacy of data analysis? We study a general class of data
analyses - computing predicate sums - with privacy. Formally, we study the
problem of estimating predicate sums {\em privately}, for sliding windows (and
other well-known decay models of data, i.e. exponential and polynomial decay).
We extend the recently proposed continual privacy model of Dwork et al.
We present algorithms for decayed sum which are \eps-differentially
private, and are accurate. For window and exponential decay sums, our
algorithms are accurate up to additive 1/\eps and polylog terms in the range
of the computed function; for polynomial decay sums which are technically more
challenging because partial solutions do not compose easily, our algorithms
incur additional relative error. Further, we show lower bounds, tight within
polylog factors and tight with respect to the dependence on the probability of
error
CELL TYPES IN THE RAT ENDOMETRIUM: AN ONTOGENETIC ULTRASTRUCTURAL STUDY
Fifty female Wistar rats were used to study the endometrial cell types by ТЕМ. Ultrastructural features of the main resident (fibroblasts, epithelial cells) and transient cells (granulocytes, macrophages, plasma cells and lymphocytes) were established during the following periods: (i) prepuberty, (ii) sexual maturity, and (Hi) in aged rats. The morphological changes in the cell types are discussed with a view to clarify the endometrial tissue reorganization during ontogenesis and especially in the estrus cycle. Our results suggest that main factors affecting the cells during the phases of the estrus cycle are the ovarian steroids, actively influencing upon them in comparison with other periods
STUDY OF ACUPUNCTURE EFFECT ON NEUROSIS PATIENTS BY USING THE METHOD OF CARDIOINTERVALOGRAPHY
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