10,218 research outputs found
Diagnosis of venous incompetence inerectile dysfunction
In 26 of 214 patients with erectile dysfunction and proved venous incompetence by cavernosography, an additional bidirectional Doppler ultrasound was performed also to demonstrate venous outflow disturbances. All except one leakage in the superficial and deep dorsal veins could be demonstrated as well as 4 of 6 cavernosum-glandular shunts. Bidirectional Doppler ultrasound visualized a continuous retrograde blood flow from the sulcus coronarius to the root of the penis in superficial and deep dorsal penile veins as well as in ectopic penile veins, an orthograde blood flow in the sulcus coronarius in cavernosum-glandular shunt
Interacting electrons in polygonal quantum dots
The low-lying eigenstates of a system of two electrons confined within a
two-dimensional quantum dot with a hard polygonal boundary are obtained by
means of exact diagonalization. The transition from a weakly correlated charge
distribution for small dots to a strongly correlated "Wigner molecule" for
large dots is studied, and the behaviour at the crossover is determined. In
sufficiently large dots, a recently proposed mapping to an effective
charge-spin model is investigated, and is found to produce the correct ordering
of the energy levels and to give a good first approximation to the size of the
level spacings. We conclude that this approach is a valuable method to obtain
the low energy spectrum of few-electron quantum dots
Transverse Momentum Dependent Fragmentation and Quark Distribution Functions from the NJL-jet Model
Using the model of Nambu and Jona-Lasinio to provide a microscopic
description of both the structure of the nucleon and of the quark to hadron
elementary fragmentation functions, we investigate the transverse momentum
dependence of the unpolarized quark distributions in the nucleon and of the
quark to pion and kaon fragmentation functions. The transverse momentum
dependence of the fragmentation functions is determined within a Monte Carlo
framework, with the notable result that the average of the produced
kaons is significantly larger than that of the pions. We also find that
has a sizable $z$ dependence, in contrast with the naive Gaussian
ansatz for the fragmentation functions. Diquark correlations in the nucleon
give rise to a non-trivial flavor dependence in the unpolarized transverse
momentum dependent quark distribution functions. The of the quarks in
the nucleon are also found to have a sizable dependence. Finally, these
results are used as input to a Monte Carlo event generator for semi-inclusive
deep inelastic scattering (SIDIS), which is used to determine the average
transverse momentum squared of the produced hadrons measured in SIDIS, namely
. Again we find that the average of the produced kaons in
SIDIS is significantly larger than that of the pions and in each case \la
P_T^2 \ra has a sizable dependence.Comment: 13 pages, 17 figures, v2: minor revisions to conform with the
published version in Phys.Rev.
Bone sarcoma cumulative tumor rates in patients injected with 224Ra
Auf Grund eines Druckfehlers sind die Seiten 28-29 in der Druckvorlage nicht vorhanden
Passive decoy state quantum key distribution: Closing the gap to perfect sources
We propose a quantum key distribution scheme which closely matches the
performance of a perfect single photon source. It nearly attains the physical
upper bound in terms of key generation rate and maximally achievable distance.
Our scheme relies on a practical setup based on a parametric downconversion
source and present-day, non-ideal photon-number detection. Arbitrary
experimental imperfections which lead to bit errors are included. We select
decoy states by classical post-processing. This allows to improve the effective
signal statistics and achievable distance.Comment: 4 pages, 3 figures. State preparation correcte
Public Channel Cryptography: Chaos Synchronization and Hilbert's Tenth Problem
The synchronization process of two mutually delayed coupled deterministic
chaotic maps is demonstrated both analytically and numerically. The
synchronization is preserved when the mutually transmitted signal is concealed
by two commutative private filters that are placed on each end of the
communication channel. We demonstrate that when the transmitted signal is a
convolution of the truncated time delayed output signals or some powers of the
delayed output signals synchronization is still maintained. The task of a
passive attacker is mapped onto Hilbert's tenth problem, solving a set of
nonlinear Diophantine equations, which was proven to be in the class of
NP-Complete problems. This bridge between two different disciplines,
synchronization in nonlinear dynamical processes and the realm of the NPC
problems, opens a horizon for a new type of secure public-channel protocols
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