1,492 research outputs found
SYSTEMS-2: a randomised phase II study of radiotherapy dose escalation for pain control in malignant pleural mesothelioma
SYSTEMS-2 is a randomised study of radiotherapy dose escalation for pain control in 112 patients with malignant pleural mesothelioma (MPM). Standard palliative (20Gy/5#) or dose escalated treatment (36Gy/6#) will be delivered using advanced radiotherapy techniques and pain responses will be compared at week 5. Data will guide optimal palliative radiotherapy in MPM
Quasi-degenerate self-trapping in one-dimensional charge transfer exciton
The self-trapping by the nondiagonal particle-phonon interaction between two
quasi-degenerate energy levels of excitonic system, is studied. We propose this
is realized in charge transfer exciton, where the directions of the
polarization give the quasi-degeneracy. It is shown that this mechanism, unlike
the conventional diagonal one, allows a coexistence and resonance of the free
and self-trapped states even in one-dimensional systems and a quantitative
theory for the optical properties (light absorption and time-resolved
luminescence) of the resonating states is presented. This theory gives a
consistent resolution for the long-standing puzzles in quasi-one-dimensional
compound A-PMDA.Comment: accepted to Phys. Rev. Letter
An attempt to observe economy globalization: the cross correlation distance evolution of the top 19 GDP's
Economy correlations between the 19 richest countries are investigated
through their Gross Domestic Product increments. A distance is defined between
increment correlation matrix elements and their evolution studied as a function
of time and time window size. Unidirectional and Bidirectional Minimal Length
Paths are generated and analyzed for different time windows. A sort of critical
correlation time window is found indicating a transition for best observations.
The mean length path decreases with time, indicating stronger correlations. A
new method for estimating a realistic minimal time window to observe
correlations and deduce macroeconomy conclusions from such features is thus
suggested.Comment: to be published in the Dyses05 proceedings, in Int. J. Mod Phys C 15
pages, 5 figures, 1 tabl
Gyrofluid simulations of collisionless reconnection in the presence of diamagnetic effects
The effects of the ion Larmor radius on magnetic reconnection are
investigated by means of numerical simulations, with a Hamiltonian gyrofluid
model. In the linear regime, it is found that ion diamagnetic effects decrease
the growth rate of the dominant mode. Increasing ion temperature tends to make
the magnetic islands propagate in the ion diamagnetic drift direction. In the
nonlinear regime, diamagnetic effects reduce the final width of the island.
Unlike the electron density, the guiding center density does not tend to
distribute along separatrices and at high ion temperature, the electrostatic
potential exhibits the superposition of a small scale structure, related to the
electron density, and a large scale structure, related to the ion
guiding-center density
Gyrofluid simulations of collisionless reconnection in the presence of diamagnetic effects
The effects of the ion Larmor radius on magnetic reconnection are
investigated by means of numerical simulations, with a Hamiltonian gyrofluid
model. In the linear regime, it is found that ion diamagnetic effects decrease
the growth rate of the dominant mode. Increasing ion temperature tends to make
the magnetic islands propagate in the ion diamagnetic drift direction. In the
nonlinear regime, diamagnetic effects reduce the final width of the island.
Unlike the electron density, the guiding center density does not tend to
distribute along separatrices and at high ion temperature, the electrostatic
potential exhibits the superposition of a small scale structure, related to the
electron density, and a large scale structure, related to the ion
guiding-center density
Gyrofluid simulations of collisionless reconnection in the presence of diamagnetic effects
The effects of the ion Larmor radius on magnetic reconnection are
investigated by means of numerical simulations, with a Hamiltonian gyrofluid
model. In the linear regime, it is found that ion diamagnetic effects decrease
the growth rate of the dominant mode. Increasing ion temperature tends to make
the magnetic islands propagate in the ion diamagnetic drift direction. In the
nonlinear regime, diamagnetic effects reduce the final width of the island.
Unlike the electron density, the guiding center density does not tend to
distribute along separatrices and at high ion temperature, the electrostatic
potential exhibits the superposition of a small scale structure, related to the
electron density, and a large scale structure, related to the ion
guiding-center density
Exact solution and interfacial tension of the six-vertex model with anti-periodic boundary conditions
We consider the six-vertex model with anti-periodic boundary conditions
across a finite strip. The row-to-row transfer matrix is diagonalised by the
`commuting transfer matrices' method. {}From the exact solution we obtain an
independent derivation of the interfacial tension of the six-vertex model in
the anti-ferroelectric phase. The nature of the corresponding integrable
boundary condition on the spin chain is also discussed.Comment: 18 pages, LaTeX with 1 PostScript figur
Physical Properties of Asteroid (308635) 2005 YU55 derived from multi-instrument infrared observations during a very close Earth-Approach
The near-Earth asteroid (308635) 2005 YU55 is a potentially hazardous
asteroid which was discovered in 2005 and passed Earth on November 8th 2011 at
0.85 lunar distances. This was the closest known approach by an asteroid of
several hundred metre diameter since 1976 when a similar size object passed at
0.5 lunar distances. We observed 2005 YU55 from ground with a recently
developed mid-IR camera (miniTAO/MAX38) in N- and Q-band and with the
Submillimeter Array (SMA) at 1.3 mm. In addition, we obtained space
observations with Herschel/PACS at 70, 100, and 160 micron. Our thermal
measurements cover a wide range of wavelengths from 8.9 micron to 1.3 mm and
were taken after opposition at phase angles between -97 deg and -18 deg. We
performed a radiometric analysis via a thermophysical model and combined our
derived properties with results from radar, adaptive optics, lightcurve
observations, speckle and auxiliary thermal data. We find that (308635) 2005
YU55 has an almost spherical shape with an effective diameter of 300 to 312 m
and a geometric albedo pV of 0.055 to 0.075. Its spin-axis is oriented towards
celestial directions (lam_ecl, beta_ecl) = (60 deg +/- 30deg, -60 deg +/- 15
deg), which means it has a retrograde sense of rotation. The analysis of all
available data combined revealed a discrepancy with the radar-derived size. Our
radiometric analysis of the thermal data together with the problem to find a
unique rotation period might be connected to a non-principal axis rotation. A
low to intermediate level of surface roughness (r.m.s. of surface slopes in the
range 0.1 - 0.3) is required to explain the available thermal measurements. We
found a thermal inertia in the range 350-800 Jm^-2s^-0.5K^-1, very similar to
the rubble-pile asteroid (25143) Itokawa and indicating a mixture of low
conductivity fine regolith with larger rocks and boulders of high thermal
inertia on the surface.Comment: Accepted for publication in Astronomy & Astrophysics, 12 pages, 10
figure
Exponential Distribution of Locomotion Activity in Cell Cultures
In vitro velocities of several cell types have been measured using computer
controlled video microscopy, which allowed to record the cells' trajectories
over several days. On the basis of our large data sets we show that the
locomotion activity displays a universal exponential distribution. Thus, motion
resulting from complex cellular processes can be well described by an
unexpected, but very simple distribution function. A simple phenomenological
model based on the interaction of various cellular processes and finite ATP
production rate is proposed to explain these experimental results.Comment: 4 pages, 3 figure
Shape modeling technique KOALA validated by ESA Rosetta at (21) Lutetia
We present a comparison of our results from ground-based observations of
asteroid (21) Lutetia with imaging data acquired during the flyby of the
asteroid by the ESA Rosetta mission. This flyby provided a unique opportunity
to evaluate and calibrate our method of determination of size, 3-D shape, and
spin of an asteroid from ground-based observations. We present our 3-D
shape-modeling technique KOALA which is based on multi-dataset inversion. We
compare the results we obtained with KOALA, prior to the flyby, on asteroid
(21) Lutetia with the high-spatial resolution images of the asteroid taken with
the OSIRIS camera on-board the ESA Rosetta spacecraft, during its encounter
with Lutetia. The spin axis determined with KOALA was found to be accurate to
within two degrees, while the KOALA diameter determinations were within 2% of
the Rosetta-derived values. The 3-D shape of the KOALA model is also confirmed
by the spectacular visual agreement between both 3-D shape models (KOALA pre-
and OSIRIS post-flyby). We found a typical deviation of only 2 km at local
scales between the profiles from KOALA predictions and OSIRIS images, resulting
in a volume uncertainty provided by KOALA better than 10%. Radiometric
techniques for the interpretation of thermal infrared data also benefit greatly
from the KOALA shape model: the absolute size and geometric albedo can be
derived with high accuracy, and thermal properties, for example the thermal
inertia, can be determined unambiguously. We consider this to be a validation
of the KOALA method. Because space exploration will remain limited to only a
few objects, KOALA stands as a powerful technique to study a much larger set of
small bodies using Earth-based observations.Comment: 15 pages, 8 figures, 2 tables, accepted for publication in P&S
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