132 research outputs found
The Photodissociation of and the Solar Neutrino Problem
The extraction of the photodissociation cross sections of from Coulomb
dissociation experiments is investigated. A careful study is done on the
contributions of the E1, E2 and M1 multipolarities to the breakup. A comparison
with the data of a recent experiment is performed. It is shown that the
extraction of the radiative capture cross sections which
are relevant for the solar neutrino problem is not affected appreciably by
Coulomb reacceleration. A non-perturbative model is used for the purpose.
Emphasis is put on the perspectives for future experiments which are planned at
the University of Notre Dame, RIKEN (Japan), and GSI (Germany). An analysis of
the total yields of ``photon-point" processes in inelastic electron scattering
is also done.Comment: 23 pages, plain Latex. 12 figures available upon request
Metropolis simulations of Met-Enkephalin with solvent-accessible area parameterizations
We investigate the solvent-accessible area method by means of Metropolis
simulations of the brain peptide Met-Enkephalin at 300. For the energy
function ECEPP/2 nine atomic solvation parameter (ASP) sets are studied. The
simulations are compared with one another, with simulations with a distance
dependent electrostatic permittivity , and with vacuum
simulations (). Parallel tempering and the biased Metropolis
techniques RM are employed and their performance is evaluated. The measured
observables include energy and dihedral probability densities (pds), integrated
autocorrelation times, and acceptance rates. Two of the ASP sets turn out to be
unsuitable for these simulations. For all other systems selected configurations
are minimized in search of the global energy minima, which are found for the
vacuum and the system, but for none of the ASP models. Other
observables show a remarkable dependence on the ASPs. In particular, we find
three ASP sets for which the autocorrelations at 300K are considerably
smaller than for vacuum simulations.Comment: 10 pages and 8 figure
The structure of oppositionality: Response disposition and situational aspects
Background: The Amsterdam Scale of Oppositionality (ASO) is a recently developed self-report instrument to measure the full range of oppositionality. It was used to test the assumption that oppositionality can best be conceptualized as a combination of emotions and behaviors varying across contexts, i.e., with parents, peers and authority figures. Method: The sample consisted of 560 boys and 598 girls, aged 8 to 12 years. The thirty items of the ASO, grouped in item parcels, were analyzed using confirmatory factor analyses. Results: Results confirmed the main hypothesis. The best fitting models contained strongly related emotional and behavioral factors and three mutually related situational factors. Oppositionality appeared to be to a large extent situation-specific. Girls are more affected by the situation than boys and show less oppositionality only outside the family context. Conclusions: Results are discussed with respect to the concept of oppositionality, varying expectations for interpersonal consequences, and implications for clinical assessment and studies of inter-informant reliability
New User-Friendly Approach to Obtain an Eisenberg Plot and Its Use as a Practical Tool in Protein Sequence Analysis
The Eisenberg plot or hydrophobic moment plot methodology is one of the most frequently used methods of bioinformatics. Bioinformatics is more and more recognized as a helpful tool in Life Sciences in general, and recent developments in approaches recognizing lipid binding regions in proteins are promising in this respect. In this study a bioinformatics approach specialized in identifying lipid binding helical regions in proteins was used to obtain an Eisenberg plot. The validity of the Heliquest generated hydrophobic moment plot was checked and exemplified. This study indicates that the Eisenberg plot methodology can be transferred to another hydrophobicity scale and renders a user-friendly approach which can be utilized in routine checks in protein–lipid interaction and in protein and peptide lipid binding characterization studies. A combined approach seems to be advantageous and results in a powerful tool in the search of helical lipid-binding regions in proteins and peptides. The strength and limitations of the Eisenberg plot approach itself are discussed as well. The presented approach not only leads to a better understanding of the nature of the protein–lipid interactions but also provides a user-friendly tool for the search of lipid-binding regions in proteins and peptides
Granulocytic sarcoma (chloroma) of the oral cavity: Report of a case and literature review
SummaryA case of granulocytic sarcoma (chloroma) of the palatal mucosa is reported. Granulocytic sarcomas are composed of a localized collection of immature myeloid cells and are considered to be specific lesions of AML or the onset of a blast crisis in chronic myelogenous leukemia (CML). Localization in the oral cavity is rare. A review of the literature showed only thirty-six cases of granulocytic sarcoma in the oral cavity. In this paper we present patient’s data and an overview of the literature
Loss of viability during freeze-thaw of intact and adherent human embryonic stem cells with conventional slow-cooling protocols is predominantly due to apoptosis rather than cellular necrosis
10.1007/s11373-005-9051-9Journal of Biomedical Science133433-44
Exotic state photoproduction
It is shown that the list of unusual mesons planned for a careful study in
photoproduction can be extended by the exotic states with which should be looked for in the decay
channels in the reactions and . The full classification of the states by their
quantum numbers is presented. A simple model for the spin structure of the , , and reaction amplitudes is formulated and the tentative estimates of the
corresponding cross sections at the incident photon energy
GeV are obtained: b, b, b, and b. The problem of the
signal extraction from the natural background due to the other production channels is discussed. In particular the estimates are
presented for the , , and reaction cross sections.
Our main conclusion is that the search for the exotic
states is quite feasible at JEFLAB facility. The expected yield of the events in a 30-day run at the 100% detection
efficiency approximates events.Comment: 19 pages, revtex, 1 figure in postscipt, some comments and references
added, a few minor typos corrected, to be published in Phys. Rev.
A review of bush dog Speothos venaticus (Lund, 1842) (Carnivora, Canidae) occurrences in Paraná state, subtropical Brazil
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