1,193 research outputs found
Thurston equivalence of topological polynomials
We answer Hubbard's question on determining the Thurston equivalence class of
``twisted rabbits'', i.e. images of the ``rabbit'' polynomial under n-th powers
of the Dehn twists about its ears.
The answer is expressed in terms of the 4-adic expansion of n. We also answer
the equivalent question for the other two families of degree-2 topological
polynomials with three post-critical points.
In the process, we rephrase the questions in group-theoretical language, in
terms of wreath recursions.Comment: 40 pages, lots of figure
Technical Note: Determination of formaldehyde mixing ratios in polluted air with PTR-MS: laboratory experiments and field measurements
International audienceFormaldehyde (HCHO), the most abundant carbonyl compound in the atmosphere, is generated as an intermediate product in the oxidation of nonmethane hydrocarbons. Proton transfer reaction mass spectrometry (PTR-MS) has the capability to detect HCHO from ion signals at m/z 31 with high time-resolution. However, the detection sensitivity is low compared to other detectable species, and is considerably affected by humidity, due to back reactions between protonated HCHO and water vapor prior to analysis. We performed a laboratory calibration of HCHO by PTR-MS and examined the detection sensitivity and humidity dependence at various field strengths. Subsequently, we deployed the PTR-MS instrument in a field campaign at Mount Tai in China in June 2006 to measure HCHO in various meteorological and photochemical conditions; we also conducted intercomparison measurements by Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS). Correction of interference in the m/z 31 signals by fragments from proton transfer reactions with methyl hydroperoxide, methanol, and ethanol greatly improves agreement between the two methods, giving the correlation [HCHO]MAX-DOAS = (0.99±0.16) [HCHO]PTR-MS + (0.02±0.38), where error limits represent 95% confidence levels
A method of implementing Hartree-Fock calculations with zero- and finite-range interactions
We develop a new method of implementing the Hartree-Fock calculations. A
class of Gaussian bases is assumed, which includes the Kamimura-Gauss basis-set
as well as the set equivalent to the harmonic-oscillator basis-set. By using
the Fourier transformation to calculate the interaction matrix elements, we can
treat various interactions in a unified manner, including finite-range ones.
The present method is numerically applied to the spherically-symmetric
Hartree-Fock calculations for the oxygen isotopes with the Skyrme and the Gogny
interactions, by adopting the harmonic-oscillator, the Kamimura-Gauss and a
hybrid basis-sets. The characters of the basis-sets are discussed. Adaptable to
slowly decreasing density distribution, the Kamimura-Gauss set is suitable to
describe unstable nuclei. A hybrid basis-set of the harmonic-oscillator and the
Kamimura-Gauss ones is useful to accelerate the convergence, both for stable
and unstable nuclei.Comment: LaTex 32 pages with 6 Postscript figure
Expression of SART3 antigen and induction of CTLs by SART3-derived peptides in breast cancer patients
We recently reported the SART3 tumour-rejection antigen as possessing tumour epitopes capable of inducing HLA-class I-restricted cytotoxic T lymphocytes (CTLs). This study investigated expression of the SART3 antigen in breast cancer to explore an appropriate molecule for use in specific immunotherapy of breast cancer patients. The SART3 antigen was detected in all of the breast cancer cell lines tested, 30 of 40 (75%) breast cancer tissue samples, and 0 of 3 non-tumourous breast tissue samples. SART3 derived peptides at positions 109â118 and 315â323 induced HLA-A24 restricted CTLs that reacted to breast cancer cells from the peripheral blood mononuclear cells (PBMCs) of breast cancer patients. Therefore, the SART3 antigen and its peptides could be an appropriate molecule for use in specific immunotherapy of the majority of HLA-A24-positive breast cancer patients. © 2001 Cancer Research Campaignhttp://www.bjcancer.co
Low-grade osteosarcoma is predominant in gnathic osteosarcomas: A report of seven cases of osteosarcoma of the jaw
OBJECTIVE: Primary osteosarcoma of the jaw bones is very rare, and histological features of gnathic osteosarcoma remain obscure. The purpose of this study was to describe the clinicopathological features of gnathic osteosarcoma. MATERIALS AND METHODS: Seven cases of gnathic osteosarcoma from Japan diagnosed during the period between 2000 and 2016 were examined retrospectively. The histology of the surgical pathology materials was reviewed by two pathologists. Clinical information was obtained from the hospital's information system. RESULTS: Of the seven cases, two patients had secondary osteosarcomas. As for the five cases of primary osteosarcoma, their ages ranged from 26 to 58âyears (mean: 36.2, median: 28). Histologically, three cases were fibrotic tumors composed of spindleâshaped cells with mild to moderate nuclear atypia and the collagenous stroma accompanied by woven bones or mature lamellarâlike bones. Two cases had cartilage formation. MDM2 and CDK4 expression was observed in two out of three cases on immunostaining. The histopathology of these three cases was regarded as the counterpart of lowâgrade osteosarcomas, namely, parosteal osteosarcoma and lowâgrade central osteosarcoma, arising in long bones. CONCLUSIONS: The surprisingly high incidence (60%, 3/5 cases) of lowâgrade osteosarcoma explains the reason why gnathic osteosarcomas present a more favorable prognosis than osteosarcomas arising in long bones. Furthermore, it provides insight into the tumorigenesis mechanism of lowâgrade osteosarcomas arising in the jaw and other sites
Generator Coordinate Method Calculations for Ground and First Excited Collective States in He, O and Ca Nuclei
The main characteristics of the ground and, in particular, the first excited
monopole state in the He, O and Ca nuclei are studied
within the generator coordinate method using Skyrme-type effective forces and
three construction potentials, namely the harmonic-oscillator, the square-well
and Woods-Saxon potentials. Calculations of density distributions, radii,
nucleon momentum distributions, natural orbitals, occupation numbers and
depletions of the Fermi sea, as well as of pair density and momentum
distributions are carried out. A comparison of these quantities for both ground
and first excited monopole states with the available empirical data and with
the results of other theoretical methods are given and discussed in detail.Comment: 15 pages, LaTeX, 6 Postscript figures, submitted to EPJ
Application of 2-Deoxy-2-[18F]Fluoro-D-Galactose for Experimental Tumor Study
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The neutron halo of He in a microscopic model
The two--neutron separation energy of He has been reproduced for the
first time in a realistic parameter--free microscopic multicluster model
comprising the and clusterizations, with cluster
breathing excitations included. The contribution of the channel is
substantial. A very thick (0.85 fm) neutron halo has been found in full
agreement with the results of the latest phenomenological analysis.Comment: Submitted to Phys. Rev. C, 8 pages, Latex with Revtex, 2 figures (not
included) available on request, 08-03-9
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