766 research outputs found
On convergence towards a self-similar solution for a nonlinear wave equation - a case study
We consider the problem of asymptotic stability of a self-similar attractor
for a simple semilinear radial wave equation which arises in the study of the
Yang-Mills equations in 5+1 dimensions. Our analysis consists of two steps. In
the first step we determine the spectrum of linearized perturbations about the
attractor using a method of continued fractions. In the second step we
demonstrate numerically that the resulting eigensystem provides an accurate
description of the dynamics of convergence towards the attractor.Comment: 9 pages, 5 figure
On the density-potential mapping in time-dependent density functional theory
The key questions of uniqueness and existence in time-dependent density
functional theory are usually formulated only for potentials and densities that
are analytic in time. Simple examples, standard in quantum mechanics, lead
however to non-analyticities. We reformulate these questions in terms of a
non-linear Schr\"odinger equation with a potential that depends non-locally on
the wavefunction.Comment: 8 pages, 2 figure
Phototesting and photoprotection in LE
Photosensitivity and induction of skin lesions following UV radiation is a common problem of patients with cutaneous and systemic forms of lupus erythematosus. The detrimental effect of UV radiation to patients with lupus erythematosus was already recognized in the last century. Skin lesions can now be provoked under standardized conditions allowing the diagnosis and classification of patients with photosensitive disorders. The aim of this review is to give an overview on the history, test procedure and test results in patients with lupus erythematosus
Higher order Schrodinger and Hartree-Fock equations
The domain of validity of the higher-order Schrodinger equations is analyzed
for harmonic-oscillator and Coulomb potentials as typical examples. Then the
Cauchy theory for higher-order Hartree-Fock equations with bounded and Coulomb
potentials is developed. Finally, the existence of associated ground states for
the odd-order equations is proved. This renders these quantum equations
relevant for physics.Comment: 19 pages, to appear in J. Math. Phy
Gene induction during differentiation of human monocytes into dendritic cells: an integrated study at the RNA and protein levels
Changes in gene expression occurring during differentiation of human
monocytes into dendritic cells were studied at the RNA and protein levels.
These studies showed the induction of several gene classes corresponding to
various biological functions. These functions encompass antigen processing and
presentation, cytoskeleton, cell signalling and signal transduction, but also
an increase in mitochondrial function and in the protein synthesis machinery,
including some, but not all, chaperones. These changes put in perspective the
events occurring during this differentiation process. On a more technical
point, it appears that the studies carried out at the RNA and protein levels
are highly complementary.Comment: website publisher:
http://www.springerlink.com/content/ha0d2c351qhjhjdm
Interannual variations in degree-2 Earth's gravity coefficients C-2,C-0, C-2,C-2, and S-2,S-2 reveal large-scale mass transfers of climatic origin
ISI Document Delivery No.: 208EO Times Cited: 0 Cited Reference Count: 24 Cited References: Boening C, 2012, GEOPHYS RES LETT, V39, DOI 10.1029/2012GL053055 CAZENAVE A, 2012, MAR GEOD S1, V35, P82 Chao BF, 2003, GEOCHEM GEOPHY GEOSY, V4, DOI 10.1029/2003GC000589 Chen JL, 2005, J GEODESY, V78, P535, DOI 10.1007/s00190-004-0417-y Cheng M., 2013, J GEOPHYS RES SOLID, V118, P1, DOI 10. 1002/jgrb. 50058 Cheng MK, 2004, J GEOPHYS RES-SOL EA, V109, DOI 10.1029/2004JB003028 Cox CM, 2002, SCIENCE, V297, P831, DOI 10.1126/science.1072188 Desai SD, 2002, J GEOPHYS RES-OCEANS, V107, DOI 10.1029/2001JC001224 Dickey JO, 2002, SCIENCE, V298, P1975, DOI 10.1126/science.1077777 Doll P, 2003, J HYDROL, V270, P105, DOI 10.1016/S0022-1694(02)00283-4 Forste C, 2008, J GEODESY, V82, P331, DOI 10.1007/s00190-007-0183-8 Gu GJ, 2011, J CLIMATE, V24, P2258, DOI 10.1175/2010JCLI3727.1 Ishii M, 2009, J OCEANOGR, V65, P287, DOI 10.1007/s10872-009-0027-7 Levitus S, 2012, GEOPHYS RES LETT, V39, DOI 10.1029/2012GL051106 Llovel W, 2011, GLOBAL PLANET CHANGE, V75, P76, DOI 10.1016/j.gloplacha.2010.10.008 Lyard F, 2006, OCEAN DYNAM, V56, P394, DOI 10.1007/s10236-006-0086-x Marcus SL, 2009, GEOPHYS RES LETT, V36, DOI 10.1029/2009GL041130 Milly PCD, 2002, J HYDROMETEOROL, V3, P283, DOI 10.1175/1525-7541(2002)0032.0.CO;2 Nerem RS, 2011, GEOPHYS RES LETT, V38, DOI 10.1029/2011GL047879 Pavlis NK, 2012, J GEOPHYS RES-SOL EA, V117, DOI 10.1029/2011JB008916 Pearlman MR, 2002, ADV SPACE RES, V30, P135, DOI 10.1016/S0273-1177(02)00277-6 Roy K, 2011, GEOPHYS RES LETT, V38, DOI 10.1029/2011GL047282 Syed TH, 2009, J HYDROMETEOROL, V10, P22, DOI 10.1175/2008JHM993.1 Zhang Y, 1997, J CLIMATE, V10, P1004, DOI 10.1175/1520-0442(1997)0102.0.CO;2 Meyssignac, B. Lemoine, J. M. Cheng, M. Cazenave, A. Gegout, P. Maisongrande, P. Centre National d'Etudes Spatiales (CNES); NASA [NNX12AK13G] This work was supported by the Centre National d'Etudes Spatiales (CNES). The CSR time series was produced by NASA's MEaSUREs program under JPL contract. M. K. Cheng is supported by NASA grant NNX12AK13G. The altimeter products used here were produced by Ssalto/Duacs and distributed by AVISO with support from CNES. 0 AMER GEOPHYSICAL UNION WASHINGTON GEOPHYS RES LETTSeveral recent studies have shown evidences for large water transfers in the climate system at interannual to decadal time scales, in particular during El Nino-Southern Oscillation events. In this study, we investigate further these water transfers and their signature in the gravity field. We analyze variations of the low-degree spherical harmonics C-2,C-0 (Earth's oblateness), C-2,C-2, and S-2,S-2 (eccentricity at the Earth's equator) from satellite laser ranging data during the 19 year period 1993-2012. We also estimate the water mass transfers in the climate system using satellite altimetry corrected for the steric effect, atmospheric reanalysis, and land hydrology models. We find a large signal in the water mass redistribution during the 1997/1998 El Nino which is consistent with an increase of the ocean mass in the tropical Pacific, a decrease of water storage in the Amazon Basin, and an increase of water storage in the Congo Basin
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Global sea level budget 1993-present
Global mean sea level is an integral of changes occurring in the climate system in response to
unforced climate variability as well as natural and anthropogenic forcing factors. Its temporal
evolution allows detecting changes (e.g., acceleration) in one or more components. Study of
the sea level budget provides constraints on missing or poorly known contributions, such as
the unsurveyed deep ocean or the still uncertain land water component. In the context of the
World Climate Research Programme Grand Challenge entitled “Regional Sea Level and
Coastal Impacts”, an international effort involving the sea level community worldwide has
been recently initiated with the objective of assessing the various data sets used to estimate
components of the sea level budget during the altimetry era (1993 to present). These data sets
are based on the combination of a broad range of space-based and in situ observations, model
estimates and algorithms. Evaluating their quality, quantifying uncertainties and identifying
sources of discrepancies between component estimates is extremely useful for various
applications in climate research. This effort involves several tens of scientists from about fifty
research teams/institutions worldwide (www.wcrp-climate.org/grand-challenges/gc-sea-
level). The results presented in this paper are a synthesis of the first assessment performed
during 2017-2018. We present estimates of the altimetry-based global mean sea level (average
rate of 3.1 +/- 0.3 mm/yr and acceleration of 0.1 mm/yr2 over 1993-present), as well as of the
different components of the sea level budget (http://doi.org/10.17882/54854). We further
examine closure of the sea level budget, comparing the observed global mean sea level with
the sum of components. Ocean thermal expansion, glaciers, Greenland and Antarctica
contribute by 42%, 21%, 15% and 8% to the global mean sea level over the 1993-present. We
also study the sea level budget over 2005-present, using GRACE-based ocean mass estimates
instead of sum of individual mass components. Results show closure of the sea level budget
within 0.3 mm/yr. Substantial uncertainty remains for the land water storage component, as
shown in examining individual mass contributions to sea level
Orbital stability of periodic waves for the nonlinear Schroedinger equation
The nonlinear Schroedinger equation has several families of quasi-periodic
travelling waves, each of which can be parametrized up to symmetries by two
real numbers: the period of the modulus of the wave profile, and the variation
of its phase over a period (Floquet exponent). In the defocusing case, we show
that these travelling waves are orbitally stable within the class of solutions
having the same period and the same Floquet exponent. This generalizes a
previous work where only small amplitude solutions were considered. A similar
result is obtained in the focusing case, under a non-degeneracy condition which
can be checked numerically. The proof relies on the general approach to orbital
stability as developed by Grillakis, Shatah, and Strauss, and requires a
detailed analysis of the Hamiltonian system satisfied by the wave profile.Comment: 34 pages, 7 figure
Well-posedness for a model of individual clustering
25 pagesInternational audienceWe study the well-posedness of a model of individual clustering. Given p > N ≥ 1 and an initial condition in W 1,p (Ω), the local existence and uniqueness of a strong solution is proved. We next consider two specific reproduction rates and show global existence if N = 1, as well as, the convergence to steady states for one of these rates
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