1,079 research outputs found
Qualitative features of periodic solutions of KdV
In this paper we prove new qualitative features of solutions of KdV on the
circle. The first result says that the Fourier coefficients of a solution of
KdV in Sobolev space , admit a WKB type expansion up to first
order with strongly oscillating phase factors defined in terms of the KdV
frequencies. The second result provides estimates for the approximation of such
a solution by trigonometric polynomials of sufficiently large degree
Oral Immunization of Wildlife Against Rabies: Concept and First Field Experiments
The possibility of immunizing carnivores against rabies with live attenuated vaccine administered by the oral route was raised by North American scientists in the 1960s. Subsequently, several American and European teams tested different vaccine strains in the laboratory for efficacy and safety and studied vaccine stabilization, vaccine delivery systems, baIt acceptance by wl1d ammals, and bait distribution schemes. The first field trial of a cloned SAD (Street Alabama Dufferin) strain in baits designed to immunize foxes orally ~as conducted in an Alpine valley in Switzerland in 1978. A population containing ∼60% immune foxes at the valley entrance stopped the spread of the disease into untreated upper parts of the valley. T~e strategic use of oral vaccination of foxes in additional regions of SWItzerland resulted m freedom from the zoonosis in four-fifths of the countr
Retinoid receptors in ovarian cancer: expression and prognosis
Background: Ovarian cancer is frequently lethal despite aggressive multimodal therapy, and new therapies are therefore needed. Retinoids are potential candidate drugs: they prevent the development of ovarian carcinoma and enhance the efficacy of cytotoxic drugs in ovarian cancer cells. At present, little is known about the retinoid receptor expression in ovarian cancer. Patients and methods: The retinoid receptors comprise two classes, retinoic acid receptors (RARs) and retinoid X receptors (RXRs), each with three subclasses, α, β and γ. We investigated the expression of the subtypes RARα, RARγ, RXRα and RXRβ by immunohistochemistry in ovarian cancers of 80 patients, and assessed their prognostic significance. In addition, we quantified the expression of retinoid receptor mRNA using real-time PCR and correlated the results with clinical characteristics. Results: RARα and RXRβ were highly expressed in a majority of ovarian cancers, particularly in advanced stages. High expression of RARα was an independent negative prognostic factor of survival in addition to FIGO stage, age and p53 accumulation. The mRNA expression of retinoid receptors did not correlate with clinical properties of the tumors. Conclusions: Retinoic acid receptors are frequently and strongly expressed in epithelial ovarian cancer and may be indicators of an adverse prognosis. This study provides the molecular basis for the therapeutic use of retinoids in ovarian cance
Oral Immunization of Wildlife Against Rabies: Concept and First Field Experiments
The possibility of immunizing carnivores against rabies with live attenuated vaccine administered by the oral route was raised by North American scientists in the 1960s. Subsequently, several American and European teams tested different vaccine strains in the laboratory for efficacy and safety and studied vaccine stabilization, vaccine delivery systems, baIt acceptance by wl1d ammals, and bait distribution schemes. The first field trial of a cloned SAD (Street Alabama Dufferin) strain in baits designed to immunize foxes orally ~as conducted in an Alpine valley in Switzerland in 1978. A population containing ∼60% immune foxes at the valley entrance stopped the spread of the disease into untreated upper parts of the valley. T~e strategic use of oral vaccination of foxes in additional regions of SWItzerland resulted m freedom from the zoonosis in four-fifths of the country
Global Birkhoff coordinates for the periodic Toda lattice
In this paper we prove that the periodic Toda lattice admits globally defined
Birkhoff coordinates.Comment: 32 page
Nekhoroshev theorem for the periodic Toda lattice
The periodic Toda lattice with sites is globally symplectomorphic to a
two parameter family of coupled harmonic oscillators. The action
variables fill out the whole positive quadrant of . We prove that in
the interior of the positive quadrant as well as in a neighborhood of the
origin, the Toda Hamiltonian is strictly convex and therefore Nekhoroshev's
theorem applies on (almost) all parts of phase space.Comment: 28 page
Retinoid receptors in ovarian cancer: expression and prognosis.
BACKGROUND
Ovarian cancer is frequently lethal despite aggressive multimodal therapy, and new therapies are therefore needed. Retinoids are potential candidate drugs: they prevent the development of ovarian carcinoma and enhance the efficacy of cytotoxic drugs in ovarian cancer cells. At present, little is known about the retinoid receptor expression in ovarian cancer.
PATIENTS AND METHODS
The retinoid receptors comprise two classes, retinoic acid receptors (RARs) and retinoid X receptors (RXRs), each with three subclasses, alpha, beta and gamma. We investigated the expression of the subtypes RARalpha, RARgamma, RXRalpha and RXRbeta by immunohistochemistry in ovarian cancers of 80 patients, and assessed their prognostic significance. In addition, we quantified the expression of retinoid receptor mRNA using real-time PCR and correlated the results with clinical characteristics.
RESULTS
RARalpha and RXRbeta were highly expressed in a majority of ovarian cancers, particularly in advanced stages. High expression of RARalpha was an independent negative prognostic factor of survival in addition to FIGO stage, age and p53 accumulation. The mRNA expression of retinoid receptors did not correlate with clinical properties of the tumors.
CONCLUSIONS
Retinoic acid receptors are frequently and strongly expressed in epithelial ovarian cancer and may be indicators of an adverse prognosis. This study provides the molecular basis for the therapeutic use of retinoids in ovarian cancer
Dog Ecology and Dog Rabies Control
Dog populations, like other populations, depend on the availability of resources (food, water, and shelter). Humans either make available or deliberately withhold resources for varying proportions of dog populations. Dog-keeping practices and the duties of responsible ownership vary with the cultural setting. Dog populations often attain densities that allow the species to be a main host of rabies. The epidemiology of dog rabies is not well understood, despite the easy access to dog populations. Today dog rabies is predomina~t in developing countries. In addition to the high rate of exposure of humans to dogs, tradItional medical beliefs and practices are the most important cultural factors that lead to high numbers of cases of human rabies. Dog rabies control programs have been succe~sful in the past, but most are failing today. Program development should follow managenal principles and take into consideration the biology of dog populations as w~ll as. cultural constraints. Elimination of stray dogs IS not an effIcIent means of controllIng eIther the dog population or rabies, but it may create public awarenes
Asymptotic Giant Branch models at very low metallicity
In this paper we present the evolution of a low mass model (initial mass
M=1.5 Msun) with a very low metal content (Z=5x10^{-5}, equivalent to
[Fe/H]=-2.44). We find that, at the beginning of the AGB phase, protons are
ingested from the envelope in the underlying convective shell generated by the
first fully developed thermal pulse. This peculiar phase is followed by a deep
third dredge up episode, which carries to the surface the freshly synthesized
13C, 14N and 7Li. A standard TP-AGB evolution, then, follows. During the proton
ingestion phase, a very high neutron density is attained and the s-process is
efficiently activated. We therefore adopt a nuclear network of about 700
isotopes, linked by more than 1200 reactions, and we couple it with the
physical evolution of the model. We discuss in detail the evolution of the
surface chemical composition, starting from the proton ingestion up to the end
of the TP-AGB phase.Comment: Accepted for Publication on PAS
128Xe and 130Xe: Testing He-shell burning in AGB stars
The s-process branching at 128I has been investigated on the basis of new,
precise experimental (n,g) cross sections for the s-only isotopes 128Xe and
130Xe. This branching is unique, since it is essentially determined by the
temperature- and density-sensitive stellar decay rates of 128I and only
marginally affected by the specific stellar neutron flux. For this reason it
represents an important test for He-shell burning in AGB stars. The description
of the branching by means of the complex stellar scenario reveals a significant
sensitivity to the time scales for convection during He shell flashes, thus
providing constraints for this phenomenon. The s-process ratio 128Xe/130Xe
deduced from stellar models allows for a (9+-3)% p-process contribution to
solar 128Xe, in agreement with the Xe-S component found in meteoritic presolar
SiC grains.Comment: 24 pages, 9 figures, accepted for publication in Astophysical Journa
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