343 research outputs found
Endoscopy in Renal Cancer Organ Preservation Treatments
This chapter traces the shift in treatment of localised renal cancer from major open surgery to endoscopic (ie laparoscopy) techniques. It also details the shift in treatment intent for localised Renal cancer toward Organ preservation. With advancement in technology and experience, the principles of endoscopic surgery have been adapted to treat renal malignancy with minimum complications and with maximal preservation of Renal function so much so that endoscopic techniques are seen as the “gold standard” by many. The chapter details these minimally invasive techniques of laparoscopic and Robotic partial nephrectomy and compares and contrasts both Oncological and Functional outcomes from both
Hyperbolic Space Cosmologies
We present a systematic study of accelerating cosmologies obtained from
M/string theory compactifications of hyperbolic spaces with time-varying
volume. A set of vacuum solutions where the internal space is a product of
hyperbolic manifolds is found to give qualitatively the same accelerating
four-dimensional FLRW universe behavior as a single hyperbolic space. We also
examine the possibility that our universe is a hyperbolic space and provide
exact Milne type solutions, as well as intersecting S-brane solutions. When
both the usual 4D spacetime and the m-dimensional internal space are
hyperbolic, we find eternally accelerating cosmologies for , with and
without form field backgrounds. In particular, the effective potential for a
magnetic field background in the large 3 dimensions is positive definite with a
local minimum and thus enhances the eternally accelerating expansion.Comment: 33 pages, 2 figures; v2 refs added; v3 minor change in text, JHEP
versio
Precision Electroweak Observables in the Minimal Moose Little Higgs Model
Little Higgs theories, in which the Higgs particle is realized as the
pseudo-Goldstone boson of an approximate global chiral symmetry have generated
much interest as possible alternatives to weak scale supersymmetry. In this
paper we analyze precision electroweak observables in the Minimal Moose model
and find that in order to be consistent with current experimental bounds, the
gauge structure of this theory needs to be modified. We then look for viable
regions of parameter space in the modified theory by calculating the various
contributions to the S and T parameters.Comment: v2: 17 pages, 9 figures. Typeset in JHEP style. Added a references
and two figures showing parameter space for each of two reference points.
Corrected typo
Constant magnetic field in closed string theory: an exactly solvable model
We consider a simple model describing a closed bosonic string in a constant
magnetic field. Exact conformal invariance demands also the presence of a
non-trivial metric and antisymmetric tensor (induced by the magnetic field).
The model is invariant under target space duality in a compact Kaluza-Klein
direction introduced to couple the magnetic field. Like open string theory in a
constant gauge field, or closed string theory on a torus, this model can be
straightforwardly quantized and solved with its spectrum of states and
partition function explicitly computed. Above some critical value of the
magnetic field an infinite number of states become tachyonic, suggesting a
presence of phase transition. We also construct heterotic string
generalisations of this bosonic model in which the constant magnetic field is
embedded either in the Kaluza-Klein or internal gauge group sector.Comment: 39 pages, harvmac (some corrections and addenda; version to appear in
Nuclear Physics
Sub-wavelength lithography over extended areas
We demonstrate a systematic approach to sub-wavelength resolution
lithographic image formation on films covering areas larger than a wavelength
squared. For example, it is possible to make a lithographic pattern with a
feature size resolution of by using a particular -photon, multi-mode entangled state, where , and banks of birefringent
plates. By preparing a statistically mixed such a state one can form any pixel
pattern on a pixel grid occupying a square
with a side of wavelengths. Hence, there is a trade-off between
the exposed area, the minimum lithographic feature size resolution, and the
number of photons used for the exposure. We also show that the proposed method
will work even under non-ideal conditions, albeit with somewhat poorer
performance.Comment: 8 pages, 8 figures, 1 table. Written in RevTe
Localized Intersections of Non-Extremal p-branes and S-branes
A class of solutions to Supergravity in 10 or 11 dimensions is presented
which extends the non-standard or semi-local intersections of Dp-branes to the
case of non-extremal p-branes. The type of non-extremal solutions involved in
the intersection is free and we provide two examples involving black-branes
and/or D-\bar{D} systems. After a rotation among the time coordinate and a
relatively transverse radial direction the solutions admit the interpretation
of an intersection among D-branes and S-branes. We speculate on the relevance
of these configurations both to study time dependent phenomena in the AdS/CFT
correspondence as well as to construct cosmological brane-world scenarios
within String Theory admitting accelerating expansion of the Universe.Comment: 31 pages, latex file; v2: typos corrected and references adde
Development of a Keetch and Byram based drought index sensitive to forest management in Mediterranean conditions
[EN] The present work aims to take a closer look at the behavior of two releases of the Keetch Byram droughtindex (KBDI) under different forest management strategies in Mediterranean conditions. Since theseversions of the index were demonstrated to be insensitive to the changes in water balance caused bydifferent thinning treatments, a new KBDI-based index sensitive to silviculture operations was developed.This new approach enabled us to simulate the benefits achieved from a thinning operation in terms offorest fire risk reduction. Abatements of 22.5% and 26.4% in KBDI were obtained for the 2009 and 2010high-risk forest fire periods, respectively, due to thinning. The reductions observed in the short-term didnot disappear in a long term. A plot thinned 10 years ago showed KBDI reductions of 12.5% and 6.7% withrespect to a non-managed plot (control treatment) in the same period. Finally, in order to make possibleapplication of the new index to other stands, coefficients of the index were based on well-known andeasy to get tree-related and physiological variables.This study is part of the research project: "CGL2011-28776-C02-02, Hydrological characterization of forest structures at plot scale for an adaptive management, Hydrosil", funded by the Spanish Ministry of Science and Innovation and FEDER funds.García Prats, A.; Campo García, ADD.; Tarcisio Fernandes, JG.; Molina Herrera, A. (2015). Development of a Keetch and Byram based drought index sensitive to forest management in Mediterranean conditions. Agricultural and Forest Meteorology. (205):40-50. https://doi.org/10.1016/j.agrformet.2015.02.009S405020
Electromagnetic Strings: Complementarity between Time and Temperature
We investigate some of the intricate features in a gravity decoupling limit
of a open bosonic string theory, in a constant electromagnetic (EM-) field. We
explain the subtle nature of space-time at short distances, due to its
entanglement with the gauge field windings in the theory. Incorporating the
mass-shell condition in the theory, we show that the time coordinate is small,
of the order of EM-string scale, and the space coordinates are large. We
perform a careful analysis in the critical regime to describe the decoupling of
a series of gauge-string windings in successions, just below the Hagedorn
temperature. We argue for the condensation of gauge-string at the Hagedorn
temperature, which is followed by the decoupling of tachyonic particles. We
demonstrate the phenomena by revoking the effective noncommutative dynamics for
the D(3)-brane and obtain nonlinear corrections to U(1) gauge theory. We
discuss the spontaneous breaking of noncommutative U(1) symmetry and show that
the Hagedorn phase is described by the noninteracting gauge particles. The
notion of time reappears in the phase at the expense of temperature. It
suggests a complementarity between two distinct notions, time and temperature,
at short distances.Comment: 32 pages, 2 figures, renamed title, added clarification on winding
modes, corrected typos, added reference
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