7,563 research outputs found
Probing the topological structure of the QCD vacuum with overlap fermions
Overlap fermions implement exact chiral symmetry on the lattice and are thus
an appropriate tool for investigating the chiral and topological structure of
the QCD vacuum. We study various chiral and topological aspects on
Luescher-Weisz-type quenched gauge field configurations using overlap fermions
as a probe. Particular emphasis is placed upon the analysis of the spectral
density and the localisation properties of the eigenmodes as well as on the
local structure of topological charge fluctuations.Comment: 8 pages, 6 figures, talk given at the Workshop on Computational
Hadron Physics, Nicosia, Cyprus, September 14-17, 2005; v2: Fig.6 corrected,
statistics in Fig. 4-6 increased, minor text change
Equation of state for the MCFL phase and its implications for compact star models
Using the solutions of the gap equations of the magnetic-color-flavor-locked
(MCFL) phase of paired quark matter in a magnetic field, and taking into
consideration the separation between the longitudinal and transverse pressures
due to the field-induced breaking of the spatial rotational symmetry, the
equation of state (EoS) of the MCFL phase is self-consistently determined. This
result is then used to investigate the possibility of absolute stability, which
turns out to require a field-dependent bag constant to hold. That is, only if
the bag constant varies with the magnetic field, there exists a window in the
magnetic field vs. bag constant plane for absolute stability of strange matter.
Implications for stellar models of magnetized (self-bound) strange stars and
hybrid (MCFL core) stars are calculated and discussed.Comment: 11 pp. 11 figure
Neutrino oscillations with disentanglement of a neutrino from its partners
We bring attention to the fact that in order to understand existing data on
neutrino oscillations, and to design future experiments, it is imperative to
appreciate the role of quantum entanglement. Once this is accounted for, the
resulting energy-momentum conserving phenomenology requires a single new
parameter related to disentanglement of a neutrino from its partners. This
parameter may not be CP symmetric. We illustrate the new ideas, with
potentially measurable effects, in the context of a novel experiment recently
proposed by Gavrin, Gorbachev, Veretenkin, and Cleveland. The strongest impact
of our ideas is on the resolution of various anomalies in neutrino oscillations
and on neutrino propagation in astrophysical environments.Comment: 6 page
Scaling Relations and Exponents in the Growth of Rough Interfaces Through Random Media
The growth of a rough interface through a random media is modelled by a
continuous stochastic equation with a quenched noise. By use of the Novikov
theorem we can transform the dependence of the noise on the interface height
into an effective temporal correlation for different regimes of the evolution
of the interface. The exponents characterizing the roughness of the interface
can thus be computed by simple scaling arguments showing a good agreement with
recent experiments and numerical simulations.Comment: 4 pages, RevTex, twocolumns, two figures (upon request). To appear in
Europhysics Letter
Nucleation of quark matter bubbles in neutron stars
The thermal nucleation of quark matter bubbles inside neutron stars is
examined for various temperatures which the star may realistically encounter
during its lifetime. It is found that for a bag constant less than a critical
value, a very large part of the star will be converted into the quark phase
within a fraction of a second. Depending on the equation of state for neutron
star matter and strange quark matter, all or some of the outer parts of the
star may subsequently be converted by a slower burning or a detonation.Comment: 13 pages, REVTeX, Phys.Rev.D (in press), IFA 93-32. 5 figures (not
included) available upon request from [email protected]
Treatment of benign prostatic hyperplasia by natural drugs
Benign prostatic hyperplasia (BPH) is one of the most common urinary diseases affecting men, generally after the age of 50. The prevalence of this multifactorial disease increases with age. With aging, the plasma level of testosterone decreases, as well as the testosterone/estrogen ratio, resulting in increased estrogen activity, which may facilitate the hyperplasia of the prostate cells. Another theory focuses on dihydrotestosterone (DHT) and the activity of the enzyme 5α-reductase, which converts testosterone to DHT. In older men, the activity of this enzyme increases, leading to a decreased testosterone/DHT ratio. DHT may promote prostate cell growth, resulting in hyperplasia. Some medicinal plants and their compounds act by modulating this enzyme, and have the above-mentioned targets. This review focuses on herbal drugs that are most widely used in the treatment of BPH, including pumpkin seed, willow herb, tomato, maritime pine bark, Pygeum africanum bark, rye pollen, saw palmetto fruit, and nettle root, highlighting the latest results of preclinical and clinical studies, as well as safety issues. In addition, the pharmaceutical care and other therapeutic options of BPH, including pharmacotherapy and surgical options, are discussed, summarizing and comparing the advantages and disadvantages of each therapy
The 1st INTEGRAL SPI-ACS Gamma-Ray Burst Catalogue
We present the sample of gamma-ray bursts detected with the anti-coincidence
shield ACS of the spectrometer SPI on-board INTEGRAL for the first 26.5 months
of mission operation (up to Jan 2005). SPI-ACS works as a nearly
omnidirectional gamma-ray burst detector above ~80 keV but lacks spatial and
spectral information. In this catalogue, the properties derived from the 50 ms
light curves (e.g., T90, Cmax, Cint, variability, V/Vmax) are given for each
candidate burst in the sample. A strong excess of very short events with
durations <0.25 s is found. This population is shown to be significantly
different from the short- and long-duration burst sample by means of the
intensity distribution and V/Vmax test and is certainly connected with cosmic
ray hits in the detector. A rate of 0.3 true gamma-ray bursts per day is
observed.Comment: 10 pages, 9 figures, A&A accepte
Photoproduction of Long-Lived Holes and Electronic Processes in Intrinsic Electric Fields Seen through Photoinduced Absorption and Dichroism in Ca_3Ga_{2-x}Mn_xGe_3O_{12} Garnets
Long-lived photoinduced absorption and dichroism in the
Ca_3Ga_{2-x}Mn_xGe_3O_{12} garnets with x < 0.06 were examined versus
temperature and pumping intensity. Unusual features of the kinetics of
photoinduced phenomena are indicative of the underlying electronic processes.
The comparison with the case of Ca_3Mn_2Ge_3O_{12}, explored earlier by the
authors, permits one to finally establish the main common mechanisms of
photoinduced absorption and dichroism caused by random electric fields of
photoproduced charges (hole polarons). The rate of their diffusion and
relaxation through recombination is strongly influenced by the same fields,
whose large statistical straggling is responsible for a broad continuous set of
relaxation components (observed in the relaxation time range from 1 to about
1000 min). For Ca_3Ga_{2-x}Mn_xGe_3O_{12}, the time and temperature dependences
of photoinduced absorption and dichroism bear a strong imprint of structure
imperfection increasing with x.Comment: 20 pages, 10 figure
Continuous selections of multivalued mappings
This survey covers in our opinion the most important results in the theory of
continuous selections of multivalued mappings (approximately) from 2002 through
2012. It extends and continues our previous such survey which appeared in
Recent Progress in General Topology, II, which was published in 2002. In
comparison, our present survey considers more restricted and specific areas of
mathematics. Note that we do not consider the theory of selectors (i.e.
continuous choices of elements from subsets of topological spaces) since this
topics is covered by another survey in this volume
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