347 research outputs found
Canonical Constraints on Leptonic Cp Violation using UHCR neutrino fluxes
It is shown that one can in principle constrain the CP-violating parameter
delta from measurements of four independant |V_{ij}|^2, or three of them and a
ratio, in the leptonic sector. To quantify our approach, using unitarity, we
derive simple expressions in terms of four independant |V_{ij}|^2 for
cos(delta) and an expression for sin^2(delta) from J^2. Thus, depending on the
values of |V_{ij}| and their accuracy, we can set meaningful limits on |delta|.
To illustrate numerically, if |V_{u1}|^2 is close to 0.1 with a 10% precision,
and if |V_{e3}^2 is larger than 0.005 and for values of |V_{e2}|^2 and
|V_{u3}|^2 that stay within +-0.1 of the current experimental data leads to a
bound pi/2 < |delta| < pi. Alternatively, a certain combination of parameters
with values of |V_{e3}|^2 larger than 0.01 leads to a closed bound of 73 <
|delta| < 103. In general, we find that it is better to use |V_{u1}|^2 or
|V_{t1}|^2 as the fourth independant |V_{ij}|^2 and that over most of the
parameter space, delta is least sensitive to |V_{e3}|^2. With just three
independant measurements (solar, atmospheric and reactor) it is impossible to
set limits on the CP phase. In this respect, we study the use of ultra high
energy cosmic (UHCR) neutrino fluxes as the additional fourth information. We
find that within the SM, neutrino fluxes of all three flavours will be very
similar but that pushing current neutrino data to their extreme values still
allowed, ratios of cosmic neutrino fluxes can differ by up to 20%; such large
discrepancies could imply negligibly small CP-violation. We also study a non
radiative neutrino decay model and find that the neutrino fluxes can differ by
a factor of up to 3 within this model and that an accuracy of 10% on the
neutrino fluxes is sufficient to set interestin limits on delta.Comment: 8 pages, 2 figures, 5 table
Constrained MSSM and the electric dipole moment of the neutron
We study the constraints on the CP-violating soft-breaking phases in the
minimal supersymmetric standard model using the limits on the chromoelectric
dipole moment of the strange quark extracted from the neutron EDM experiment.
Our investigation shows that the phase mediated by the gluino exchange diagram
has to be very small, , for the common supersymmetric mass
of the order of 100 GeV. Then, solving the renormalization group equations
analytically by iterations, we calculate the electric dipole moment of the
neutron in the MSSM with CP-conserving soft-breaking parameters for the case of
three and four generations. For the three-generation case we resolve the
apparent discrepancies between order-of-magnitude estimates and numerical
calculations existing in the literature. In this case the EDM of the neutron
does not exceed . For the four-generation case we show that
there is a significant enhancement which renders the EDM of the neutron at a
measurable level of .Comment: 18 pages, LaTex, 2 fig
Live video streaming over packet networks and wireless channels
The transmission of live video over noisy channels requires very low end-to-end delay. Although automatic repeat request ensures lossless transmission, its usefulness to live video streaming is restricted to short connections because of the unbounded retransmission latency. An alternative is to use forward error correction (FEC). Since finding an optimal error protection strategy can be time expensive, FEC systems are commonly designed for the worst case condition of the channel, which limits the end-to-end performance. We study the suitability of two scalable FEC-based systems to the transmission of live video over packet networks. The first one uses Reed-Solomon codes and is appropriate for the Internet. The second one uses a product channel code and is appropriate for wireless channels. We show how fast and robust transmission can be achieved by exploiting a parametric model for the distortion-rate curve of the source coder and by using fast joint source-channel allocation algorithms. Experimental results for the 3D set partitioning in hierarchical tree video coder show that the systems have good reconstruction quality even in severe channel conditions. Finally, we compare the performance of the systems to the state-of-the-art for video transmission over the Internet. 1
Patterns in the Fermion Mixing Matrix, a bottom-up approach
We first obtain the most general and compact parametrization of the unitary
transformation diagonalizing any 3 by 3 hermitian matrix H, as a function of
its elements and eigenvalues. We then study a special class of fermion mass
matrices, defined by the requirement that all of the diagonalizing unitary
matrices (in the up, down, charged lepton and neutrino sectors) contain at
least one mixing angle much smaller than the other two. Our new parametrization
allows us to quickly extract information on the patterns and predictions
emerging from this scheme. In particular we find that the phase difference
between two elements of the two mass matrices (of the sector in question)
controls the generic size of one of the observable fermion mixing angles: i.e.
just fixing that particular phase difference will "predict" the generic value
of one of the mixing angles, irrespective of the value of anything else.Comment: 29 pages, 3 figures, references added, to appear in PR
Experiments on joint source-channel fractal image coding with unequal error protection
We propose a joint source-channel coding system for fractal image compression. We allocate the available total bit rate between the source code and a range of error-correcting codes using a Lagrange multiplier optimization technique. The principle of the proposed unequal error protection strategy is to partition the information bits into sensitivity classes and to assign one code from a range of error-correcting codes to each sensitivity class in a nearly optimal way. Experimental results show that joint source-channel coding with fractal image compression is feasible, leads to ef"cient protection strategies, and outperforms previous works in this "eld that only covered channel coding with a "xed source rate
Pulmonary Embolism Revealing Idiopathic Membranous Glomerulonephritis
We describe a case of a 55-year-old man who presented with pulmonary embolism and who was found to have nephrotic syndrome due to idiopathic membranous nephropathy. There are no other signs of nephrotic syndrome such as edema
Thymic hyperplasia in a patient with Grave's disease
Hyperplastic changes of the thymus may be found in patients with Graves' disease. However, this rarely presents as an anterior mediastinal mass, particularly among adults. In this report, we describe a 46-year old woman with Graves' disease and thymic hyperplasia
Electrodynamics of Magnetic Pulse Welding Machines: Global and Local Electrical Analogues
In this paper, a theoretical, experimental and numerical study of MPW machines is carried
out. While it is known that such machines are very complex by nature because of the coupling
between different parts, we used simple electrical analogues to describe its dynamics. A RLC
circuit modeling the whole machine is depicted and experimental results are shown. A
further study including numerical simulations allows to compute the current distribution and
estimate the magnetic field within the coil but also the magnetic pressure generated in the
process, all using a 2D model and reasonable assumptions. A late theoretical study opens
the way for innovative experimental measurements regarding the kinetics of the
deformations of metallic tubes, but also their mechanical behavior before the welding
process, making use of their capacitive properties
Association myĂ©lome multiple â maladie de Kaposi: Ă propos dâun cas
L'association KaposiâmyĂ©lome multiple est extrĂȘmement rare. Nous rapportons, le cas d'un patient ĂągĂ© de 76 ans suivi dans notre formation pour un myĂ©lome Ă immunoglobuline A kappa stade III-B selon Durie et Salmon. Ceci a Ă©tĂ© associĂ© Ă des lĂ©sions cutanĂ©es dont la biopsie cutanĂ©e Ă©tait en faveur dâune maladie de Kaposi. La sĂ©rologie de lâherpĂšs virus humain de type 8 (HHV8) est revenue positive. Une radiothĂ©rapie sur les lĂ©sions Ă©tait refusĂ©e par le patient. L'Ă©volution Ă©tait marquĂ©e par une altĂ©ration de l'Ă©tat gĂ©nĂ©ral. Le patient ayant refusĂ© la radiothĂ©rapie et toute prise en charge thĂ©rapeutique est dĂ©cĂ©dĂ©e deux mois plus tard. Nous rapportons, Ă notre connaissance, le 18Ăšme cas mondial de maladie de Kaposi associĂ©e Ă un Kahler chez un patient HHV8 positif. C'est une association exceptionnelle rendant probable le rĂŽle pathogĂ©nique de HHV8 dans le dĂ©veloppement du myĂ©lome
SUSY, the Third Generation and the LHC
We develop a bottom-up approach to studying SUSY with light stops and
sbottoms, but with other squarks and sleptons heavy and beyond reach of the
LHC. We discuss the range of squark, gaugino and Higgsino masses for which the
electroweak scale is radiatively stable over the "little hierarchy" below ~ 10
TeV. We review and expand on indirect constraints on this scenario, in
particular from flavor and CP tests. We emphasize that in this context,
R-parity violation is very well motivated. The phenomenological differences
between Majorana and Dirac gauginos are also discussed. Finally, we focus on
the light subsystem of stops, sbottom and neutralino with R-parity, in order to
probe the current collider bounds. We find that 1/fb LHC bounds are mild and
large parts of the motivated parameter space remain open, while the 10/fb data
can be much more decisive.Comment: 42 pages, 8 figures, 1 table. V2: minor corrections, references adde
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